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[PATCH v3 6/7] Row pattern recognition patch (tests).
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* [PATCH v3 6/7] Row pattern recognition patch (tests).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)

---
 src/test/regress/expected/rpr.out  | 425 +++++++++++++++++++++++++++++
 src/test/regress/parallel_schedule |   2 +-
 src/test/regress/sql/rpr.sql       | 214 +++++++++++++++
 3 files changed, 640 insertions(+), 1 deletion(-)
 create mode 100644 src/test/regress/expected/rpr.out
 create mode 100644 src/test/regress/sql/rpr.sql

diff --git a/src/test/regress/expected/rpr.out b/src/test/regress/expected/rpr.out
new file mode 100644
index 0000000000..19c054a0b8
--- /dev/null
+++ b/src/test/regress/expected/rpr.out
@@ -0,0 +1,425 @@
+--
+-- Test for row pattern definition clause
+--
+CREATE TEMP TABLE stock (
+       company TEXT,
+       tdate DATE,
+       price INTEGER
+       	       );
+INSERT INTO stock VALUES ('company1', '2023-07-01', 100);
+INSERT INTO stock VALUES ('company1', '2023-07-02', 200);
+INSERT INTO stock VALUES ('company1', '2023-07-03', 150);
+INSERT INTO stock VALUES ('company1', '2023-07-04', 140);
+INSERT INTO stock VALUES ('company1', '2023-07-05', 150);
+INSERT INTO stock VALUES ('company1', '2023-07-06', 90);
+INSERT INTO stock VALUES ('company1', '2023-07-07', 110);
+INSERT INTO stock VALUES ('company1', '2023-07-08', 130);
+INSERT INTO stock VALUES ('company1', '2023-07-09', 120);
+INSERT INTO stock VALUES ('company1', '2023-07-10', 130);
+INSERT INTO stock VALUES ('company2', '2023-07-01', 50);
+INSERT INTO stock VALUES ('company2', '2023-07-02', 2000);
+INSERT INTO stock VALUES ('company2', '2023-07-03', 1500);
+INSERT INTO stock VALUES ('company2', '2023-07-04', 1400);
+INSERT INTO stock VALUES ('company2', '2023-07-05', 1500);
+INSERT INTO stock VALUES ('company2', '2023-07-06', 60);
+INSERT INTO stock VALUES ('company2', '2023-07-07', 1100);
+INSERT INTO stock VALUES ('company2', '2023-07-08', 1300);
+INSERT INTO stock VALUES ('company2', '2023-07-09', 1200);
+INSERT INTO stock VALUES ('company2', '2023-07-10', 1300);
+SELECT * FROM stock;
+ company  |   tdate    | price 
+----------+------------+-------
+ company1 | 07-01-2023 |   100
+ company1 | 07-02-2023 |   200
+ company1 | 07-03-2023 |   150
+ company1 | 07-04-2023 |   140
+ company1 | 07-05-2023 |   150
+ company1 | 07-06-2023 |    90
+ company1 | 07-07-2023 |   110
+ company1 | 07-08-2023 |   130
+ company1 | 07-09-2023 |   120
+ company1 | 07-10-2023 |   130
+ company2 | 07-01-2023 |    50
+ company2 | 07-02-2023 |  2000
+ company2 | 07-03-2023 |  1500
+ company2 | 07-04-2023 |  1400
+ company2 | 07-05-2023 |  1500
+ company2 | 07-06-2023 |    60
+ company2 | 07-07-2023 |  1100
+ company2 | 07-08-2023 |  1300
+ company2 | 07-09-2023 |  1200
+ company2 | 07-10-2023 |  1300
+(20 rows)
+
+-- basic test using PREV
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w,
+ nth_value(tdate, 2) OVER w AS nth_second
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+ company  |   tdate    | price | first_value | last_value | nth_second 
+----------+------------+-------+-------------+------------+------------
+ company1 | 07-01-2023 |   100 |         100 |        140 | 07-02-2023
+ company1 | 07-02-2023 |   200 |             |            | 
+ company1 | 07-03-2023 |   150 |             |            | 
+ company1 | 07-04-2023 |   140 |             |            | 
+ company1 | 07-05-2023 |   150 |             |            | 
+ company1 | 07-06-2023 |    90 |          90 |        120 | 07-07-2023
+ company1 | 07-07-2023 |   110 |             |            | 
+ company1 | 07-08-2023 |   130 |             |            | 
+ company1 | 07-09-2023 |   120 |             |            | 
+ company1 | 07-10-2023 |   130 |             |            | 
+ company2 | 07-01-2023 |    50 |          50 |       1400 | 07-02-2023
+ company2 | 07-02-2023 |  2000 |             |            | 
+ company2 | 07-03-2023 |  1500 |             |            | 
+ company2 | 07-04-2023 |  1400 |             |            | 
+ company2 | 07-05-2023 |  1500 |             |            | 
+ company2 | 07-06-2023 |    60 |          60 |       1200 | 07-07-2023
+ company2 | 07-07-2023 |  1100 |             |            | 
+ company2 | 07-08-2023 |  1300 |             |            | 
+ company2 | 07-09-2023 |  1200 |             |            | 
+ company2 | 07-10-2023 |  1300 |             |            | 
+(20 rows)
+
+-- the first row start with less than or equal to 100
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+  LOWPRICE AS price <= 100,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+ company  |   tdate    | price | first_value | last_value 
+----------+------------+-------+-------------+------------
+ company1 | 07-01-2023 |   100 |         100 |        140
+ company1 | 07-02-2023 |   200 |             |           
+ company1 | 07-03-2023 |   150 |             |           
+ company1 | 07-04-2023 |   140 |             |           
+ company1 | 07-05-2023 |   150 |             |           
+ company1 | 07-06-2023 |    90 |          90 |        120
+ company1 | 07-07-2023 |   110 |             |           
+ company1 | 07-08-2023 |   130 |             |           
+ company1 | 07-09-2023 |   120 |             |           
+ company1 | 07-10-2023 |   130 |             |           
+ company2 | 07-01-2023 |    50 |          50 |       1400
+ company2 | 07-02-2023 |  2000 |             |           
+ company2 | 07-03-2023 |  1500 |             |           
+ company2 | 07-04-2023 |  1400 |             |           
+ company2 | 07-05-2023 |  1500 |             |           
+ company2 | 07-06-2023 |    60 |          60 |       1200
+ company2 | 07-07-2023 |  1100 |             |           
+ company2 | 07-08-2023 |  1300 |             |           
+ company2 | 07-09-2023 |  1200 |             |           
+ company2 | 07-10-2023 |  1300 |             |           
+(20 rows)
+
+-- second row raises 120%
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+  LOWPRICE AS price <= 100,
+  UP AS price > PREV(price) * 1.2,
+  DOWN AS price < PREV(price)
+);
+ company  |   tdate    | price | first_value | last_value 
+----------+------------+-------+-------------+------------
+ company1 | 07-01-2023 |   100 |         100 |        140
+ company1 | 07-02-2023 |   200 |             |           
+ company1 | 07-03-2023 |   150 |             |           
+ company1 | 07-04-2023 |   140 |             |           
+ company1 | 07-05-2023 |   150 |             |           
+ company1 | 07-06-2023 |    90 |             |           
+ company1 | 07-07-2023 |   110 |             |           
+ company1 | 07-08-2023 |   130 |             |           
+ company1 | 07-09-2023 |   120 |             |           
+ company1 | 07-10-2023 |   130 |             |           
+ company2 | 07-01-2023 |    50 |          50 |       1400
+ company2 | 07-02-2023 |  2000 |             |           
+ company2 | 07-03-2023 |  1500 |             |           
+ company2 | 07-04-2023 |  1400 |             |           
+ company2 | 07-05-2023 |  1500 |             |           
+ company2 | 07-06-2023 |    60 |             |           
+ company2 | 07-07-2023 |  1100 |             |           
+ company2 | 07-08-2023 |  1300 |             |           
+ company2 | 07-09-2023 |  1200 |             |           
+ company2 | 07-10-2023 |  1300 |             |           
+(20 rows)
+
+-- using NEXT
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UPDOWN)
+ DEFINE
+  START AS TRUE,
+  UPDOWN AS price > PREV(price) AND price > NEXT(price)
+);
+ company  |   tdate    | price | first_value | last_value 
+----------+------------+-------+-------------+------------
+ company1 | 07-01-2023 |   100 |         100 |        200
+ company1 | 07-02-2023 |   200 |             |           
+ company1 | 07-03-2023 |   150 |             |           
+ company1 | 07-04-2023 |   140 |         140 |        150
+ company1 | 07-05-2023 |   150 |             |           
+ company1 | 07-06-2023 |    90 |             |           
+ company1 | 07-07-2023 |   110 |         110 |        130
+ company1 | 07-08-2023 |   130 |             |           
+ company1 | 07-09-2023 |   120 |             |           
+ company1 | 07-10-2023 |   130 |             |           
+ company2 | 07-01-2023 |    50 |          50 |       2000
+ company2 | 07-02-2023 |  2000 |             |           
+ company2 | 07-03-2023 |  1500 |             |           
+ company2 | 07-04-2023 |  1400 |        1400 |       1500
+ company2 | 07-05-2023 |  1500 |             |           
+ company2 | 07-06-2023 |    60 |             |           
+ company2 | 07-07-2023 |  1100 |        1100 |       1300
+ company2 | 07-08-2023 |  1300 |             |           
+ company2 | 07-09-2023 |  1200 |             |           
+ company2 | 07-10-2023 |  1300 |             |           
+(20 rows)
+
+-- using AFTER MATCH SKIP TO NEXT ROW
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP TO NEXT ROW
+ INITIAL
+ PATTERN (START UPDOWN)
+ DEFINE
+  START AS TRUE,
+  UPDOWN AS price > PREV(price) AND price > NEXT(price)
+);
+ company  |   tdate    | price | first_value | last_value 
+----------+------------+-------+-------------+------------
+ company1 | 07-01-2023 |   100 |         100 |        200
+ company1 | 07-02-2023 |   200 |             |           
+ company1 | 07-03-2023 |   150 |             |           
+ company1 | 07-04-2023 |   140 |         140 |        150
+ company1 | 07-05-2023 |   150 |             |           
+ company1 | 07-06-2023 |    90 |             |           
+ company1 | 07-07-2023 |   110 |         110 |        130
+ company1 | 07-08-2023 |   130 |             |           
+ company1 | 07-09-2023 |   120 |             |           
+ company1 | 07-10-2023 |   130 |             |           
+ company2 | 07-01-2023 |    50 |          50 |       2000
+ company2 | 07-02-2023 |  2000 |             |           
+ company2 | 07-03-2023 |  1500 |             |           
+ company2 | 07-04-2023 |  1400 |        1400 |       1500
+ company2 | 07-05-2023 |  1500 |             |           
+ company2 | 07-06-2023 |    60 |             |           
+ company2 | 07-07-2023 |  1100 |        1100 |       1300
+ company2 | 07-08-2023 |  1300 |             |           
+ company2 | 07-09-2023 |  1200 |             |           
+ company2 | 07-10-2023 |  1300 |             |           
+(20 rows)
+
+-- match everything
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (A+)
+ DEFINE
+  A AS TRUE
+);
+ company  |   tdate    | price | first_value | last_value 
+----------+------------+-------+-------------+------------
+ company1 | 07-01-2023 |   100 |         100 |        130
+ company1 | 07-02-2023 |   200 |             |           
+ company1 | 07-03-2023 |   150 |             |           
+ company1 | 07-04-2023 |   140 |             |           
+ company1 | 07-05-2023 |   150 |             |           
+ company1 | 07-06-2023 |    90 |             |           
+ company1 | 07-07-2023 |   110 |             |           
+ company1 | 07-08-2023 |   130 |             |           
+ company1 | 07-09-2023 |   120 |             |           
+ company1 | 07-10-2023 |   130 |             |           
+ company2 | 07-01-2023 |    50 |          50 |       1300
+ company2 | 07-02-2023 |  2000 |             |           
+ company2 | 07-03-2023 |  1500 |             |           
+ company2 | 07-04-2023 |  1400 |             |           
+ company2 | 07-05-2023 |  1500 |             |           
+ company2 | 07-06-2023 |    60 |             |           
+ company2 | 07-07-2023 |  1100 |             |           
+ company2 | 07-08-2023 |  1300 |             |           
+ company2 | 07-09-2023 |  1200 |             |           
+ company2 | 07-10-2023 |  1300 |             |           
+(20 rows)
+
+-- backtracking with reclassification of rows
+-- using AFTER MATCH SKIP PAST LAST ROW
+SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (A+ B+)
+ DEFINE
+  A AS price > 100,
+  B AS price > 100
+);
+ company  |   tdate    | price | first_value | last_value 
+----------+------------+-------+-------------+------------
+ company1 | 07-01-2023 |   100 |             | 
+ company1 | 07-02-2023 |   200 | 07-02-2023  | 07-05-2023
+ company1 | 07-03-2023 |   150 |             | 
+ company1 | 07-04-2023 |   140 |             | 
+ company1 | 07-05-2023 |   150 |             | 
+ company1 | 07-06-2023 |    90 |             | 
+ company1 | 07-07-2023 |   110 | 07-07-2023  | 07-10-2023
+ company1 | 07-08-2023 |   130 |             | 
+ company1 | 07-09-2023 |   120 |             | 
+ company1 | 07-10-2023 |   130 |             | 
+ company2 | 07-01-2023 |    50 |             | 
+ company2 | 07-02-2023 |  2000 | 07-02-2023  | 07-05-2023
+ company2 | 07-03-2023 |  1500 |             | 
+ company2 | 07-04-2023 |  1400 |             | 
+ company2 | 07-05-2023 |  1500 |             | 
+ company2 | 07-06-2023 |    60 |             | 
+ company2 | 07-07-2023 |  1100 | 07-07-2023  | 07-10-2023
+ company2 | 07-08-2023 |  1300 |             | 
+ company2 | 07-09-2023 |  1200 |             | 
+ company2 | 07-10-2023 |  1300 |             | 
+(20 rows)
+
+-- backtracking with reclassification of rows
+-- using AFTER MATCH SKIP TO NEXT ROW
+SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP TO NEXT ROW
+ INITIAL
+ PATTERN (A+ B+)
+ DEFINE
+  A AS price > 100,
+  B AS price > 100
+);
+ company  |   tdate    | price | first_value | last_value 
+----------+------------+-------+-------------+------------
+ company1 | 07-01-2023 |   100 |             | 
+ company1 | 07-02-2023 |   200 | 07-02-2023  | 07-05-2023
+ company1 | 07-03-2023 |   150 | 07-03-2023  | 07-05-2023
+ company1 | 07-04-2023 |   140 | 07-04-2023  | 07-05-2023
+ company1 | 07-05-2023 |   150 |             | 
+ company1 | 07-06-2023 |    90 |             | 
+ company1 | 07-07-2023 |   110 | 07-07-2023  | 07-10-2023
+ company1 | 07-08-2023 |   130 | 07-08-2023  | 07-10-2023
+ company1 | 07-09-2023 |   120 | 07-09-2023  | 07-10-2023
+ company1 | 07-10-2023 |   130 |             | 
+ company2 | 07-01-2023 |    50 |             | 
+ company2 | 07-02-2023 |  2000 | 07-02-2023  | 07-05-2023
+ company2 | 07-03-2023 |  1500 | 07-03-2023  | 07-05-2023
+ company2 | 07-04-2023 |  1400 | 07-04-2023  | 07-05-2023
+ company2 | 07-05-2023 |  1500 |             | 
+ company2 | 07-06-2023 |    60 |             | 
+ company2 | 07-07-2023 |  1100 | 07-07-2023  | 07-10-2023
+ company2 | 07-08-2023 |  1300 | 07-08-2023  | 07-10-2023
+ company2 | 07-09-2023 |  1200 | 07-09-2023  | 07-10-2023
+ company2 | 07-10-2023 |  1300 |             | 
+(20 rows)
+
+--
+-- Error cases
+--
+-- row pattern definition variable name must not appear more than once
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ ORDER BY tdate
+ INITIAL
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price),
+  UP AS price > PREV(price)
+);
+ERROR:  syntax error at or near "ORDER"
+LINE 6:  ORDER BY tdate
+         ^
+-- pattern variable name must appear in DEFINE
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UP+ DOWN+ END)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+ERROR:  syntax error at or near "END"
+LINE 8:  PATTERN (START UP+ DOWN+ END)
+                                  ^
+-- FRAME must start at current row when row patttern recognition is used
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+ERROR:  FRAME must start at current row when row patttern recognition is used
+-- SEEK is not supported
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP TO NEXT ROW
+ SEEK
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+ERROR:  SEEK is not supported
+LINE 8:  SEEK
+         ^
+HINT:  Use INITIAL.
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 4df9d8503b..896531002b 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -98,7 +98,7 @@ test: publication subscription
 # Another group of parallel tests
 # select_views depends on create_view
 # ----------
-test: select_views portals_p2 foreign_key cluster dependency guc bitmapops combocid tsearch tsdicts foreign_data window xmlmap functional_deps advisory_lock indirect_toast equivclass
+test: select_views portals_p2 foreign_key cluster dependency guc bitmapops combocid tsearch tsdicts foreign_data window xmlmap functional_deps advisory_lock indirect_toast equivclass rpr
 
 # ----------
 # Another group of parallel tests (JSON related)
diff --git a/src/test/regress/sql/rpr.sql b/src/test/regress/sql/rpr.sql
new file mode 100644
index 0000000000..01459e619b
--- /dev/null
+++ b/src/test/regress/sql/rpr.sql
@@ -0,0 +1,214 @@
+--
+-- Test for row pattern definition clause
+--
+
+CREATE TEMP TABLE stock (
+       company TEXT,
+       tdate DATE,
+       price INTEGER
+       	       );
+INSERT INTO stock VALUES ('company1', '2023-07-01', 100);
+INSERT INTO stock VALUES ('company1', '2023-07-02', 200);
+INSERT INTO stock VALUES ('company1', '2023-07-03', 150);
+INSERT INTO stock VALUES ('company1', '2023-07-04', 140);
+INSERT INTO stock VALUES ('company1', '2023-07-05', 150);
+INSERT INTO stock VALUES ('company1', '2023-07-06', 90);
+INSERT INTO stock VALUES ('company1', '2023-07-07', 110);
+INSERT INTO stock VALUES ('company1', '2023-07-08', 130);
+INSERT INTO stock VALUES ('company1', '2023-07-09', 120);
+INSERT INTO stock VALUES ('company1', '2023-07-10', 130);
+INSERT INTO stock VALUES ('company2', '2023-07-01', 50);
+INSERT INTO stock VALUES ('company2', '2023-07-02', 2000);
+INSERT INTO stock VALUES ('company2', '2023-07-03', 1500);
+INSERT INTO stock VALUES ('company2', '2023-07-04', 1400);
+INSERT INTO stock VALUES ('company2', '2023-07-05', 1500);
+INSERT INTO stock VALUES ('company2', '2023-07-06', 60);
+INSERT INTO stock VALUES ('company2', '2023-07-07', 1100);
+INSERT INTO stock VALUES ('company2', '2023-07-08', 1300);
+INSERT INTO stock VALUES ('company2', '2023-07-09', 1200);
+INSERT INTO stock VALUES ('company2', '2023-07-10', 1300);
+
+SELECT * FROM stock;
+
+-- basic test using PREV
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w,
+ nth_value(tdate, 2) OVER w AS nth_second
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+
+-- the first row start with less than or equal to 100
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+  LOWPRICE AS price <= 100,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+
+-- second row raises 120%
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+  LOWPRICE AS price <= 100,
+  UP AS price > PREV(price) * 1.2,
+  DOWN AS price < PREV(price)
+);
+
+-- using NEXT
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UPDOWN)
+ DEFINE
+  START AS TRUE,
+  UPDOWN AS price > PREV(price) AND price > NEXT(price)
+);
+
+-- using AFTER MATCH SKIP TO NEXT ROW
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP TO NEXT ROW
+ INITIAL
+ PATTERN (START UPDOWN)
+ DEFINE
+  START AS TRUE,
+  UPDOWN AS price > PREV(price) AND price > NEXT(price)
+);
+
+-- match everything
+
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (A+)
+ DEFINE
+  A AS TRUE
+);
+
+-- backtracking with reclassification of rows
+-- using AFTER MATCH SKIP PAST LAST ROW
+SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (A+ B+)
+ DEFINE
+  A AS price > 100,
+  B AS price > 100
+);
+
+-- backtracking with reclassification of rows
+-- using AFTER MATCH SKIP TO NEXT ROW
+SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP TO NEXT ROW
+ INITIAL
+ PATTERN (A+ B+)
+ DEFINE
+  A AS price > 100,
+  B AS price > 100
+);
+
+--
+-- Error cases
+--
+
+-- row pattern definition variable name must not appear more than once
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ ORDER BY tdate
+ INITIAL
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price),
+  UP AS price > PREV(price)
+);
+
+-- pattern variable name must appear in DEFINE
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UP+ DOWN+ END)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+
+-- FRAME must start at current row when row patttern recognition is used
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
+
+-- SEEK is not supported
+SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
+ FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP TO NEXT ROW
+ SEEK
+ PATTERN (START UP+ DOWN+)
+ DEFINE
+  START AS TRUE,
+  UP AS price > PREV(price),
+  DOWN AS price < PREV(price)
+);
-- 
2.25.1


----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v3-0007-Allow-to-print-raw-parse-tree.patch"



^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13 Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 229+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <[email protected]>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 229+ messages in thread