postgres.git / summary / log / commit / refs
commit d7056bc1c71d2d876adb60dda8e0ba962e8279df
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed Mar 01 16:30:17 2023 +0000
First released in: 16.0, 11.20, 12.15, 13.11, 14.8, 15.3
Avoid fetching one past the end of translate()'s "to" parameter.
This is usually harmless, but if you were very unlucky it could
provoke a segfault due to the "to" string being right up against
the end of memory. Found via valgrind testing (so we might've
found it earlier, except that our regression tests lacked any
exercise of translate()'s deletion feature).
Fix by switching the order of the test-for-end-of-string and
advance-pointer steps. While here, compute "to_ptr + tolen"
just once. (Smarter compilers might figure that out for
themselves, but let's just make sure.)
Report and fix by Daniil Anisimov, in bug #17816.
Discussion: https://postgr.es/m/17816-70f3d2764e88a108@postgresql.org
src/backend/utils/adt/oracle_compat.c | 12 +++++++-----
src/test/regress/expected/strings.out | 6 ++++++
src/test/regress/sql/strings.sql | 1 +
3 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/oracle_compat.c b/src/backend/utils/adt/oracle_compat.c
index 5f1bc59d878..3b5b794afb3 100644
--- a/src/backend/utils/adt/oracle_compat.c
+++ b/src/backend/utils/adt/oracle_compat.c
@@ -801,7 +801,8 @@ translate(PG_FUNCTION_ARGS)
text *to = PG_GETARG_TEXT_PP(2);
text *result;
char *from_ptr,
- *to_ptr;
+ *to_ptr,
+ *to_end;
char *source,
*target;
int m,
@@ -823,6 +824,7 @@ translate(PG_FUNCTION_ARGS)
from_ptr = VARDATA_ANY(from);
tolen = VARSIZE_ANY_EXHDR(to);
to_ptr = VARDATA_ANY(to);
+ to_end = to_ptr + tolen;
/*
* The worst-case expansion is to substitute a max-length character for a
@@ -857,16 +859,16 @@ translate(PG_FUNCTION_ARGS)
}
if (i < fromlen)
{
- /* substitute */
+ /* substitute, or delete if no corresponding "to" character */
char *p = to_ptr;
for (i = 0; i < from_index; i++)
{
- p += pg_mblen(p);
- if (p >= (to_ptr + tolen))
+ if (p >= to_end)
break;
+ p += pg_mblen(p);
}
- if (p < (to_ptr + tolen))
+ if (p < to_end)
{
len = pg_mblen(p);
memcpy(target, p, len);
diff --git a/src/test/regress/expected/strings.out b/src/test/regress/expected/strings.out
index 403a29ed8c6..62698569e1a 100644
--- a/src/test/regress/expected/strings.out
+++ b/src/test/regress/expected/strings.out
@@ -2443,6 +2443,12 @@ SELECT translate('12345', '14', 'ax');
a23x5
(1 row)
+SELECT translate('12345', '134', 'a');
+ translate
+-----------
+ a25
+(1 row)
+
SELECT ascii('x');
ascii
-------
diff --git a/src/test/regress/sql/strings.sql b/src/test/regress/sql/strings.sql
index 097dcdf69e9..ca32f6bba53 100644
--- a/src/test/regress/sql/strings.sql
+++ b/src/test/regress/sql/strings.sql
@@ -787,6 +787,7 @@ SELECT ltrim('zzzytrim', 'xyz');
SELECT translate('', '14', 'ax');
SELECT translate('12345', '14', 'ax');
+SELECT translate('12345', '134', 'a');
SELECT ascii('x');
SELECT ascii('');
[parent: 6095069b40d7]