postgres.git / summary / log / commit / refs

commit    e6a48014df39dcddbbcadb9479c3bcba9d049f44
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Fri Jul 29 17:30:50 2022 +0000
First released in: 16.0, 10.22, 11.17, 12.12, 13.8, 14.5, 15.0

    In transformRowExpr(), check for too many columns in the row.
    
    A RowExpr with more than MaxTupleAttributeNumber columns would fail at
    execution anyway, since we cannot form a tuple datum with more than that
    many columns.  While heap_form_tuple() has a check for too many columns,
    it emerges that there are some intermediate bits of code that don't
    check and can be driven to failure with sufficiently many columns.
    Checking this at parse time seems like the most appropriate place to
    install a defense, since we already check SELECT list length there.
    
    While at it, make the SELECT-list-length error use the same errcode
    (TOO_MANY_COLUMNS) as heap_form_tuple does, rather than the generic
    PROGRAM_LIMIT_EXCEEDED.
    
    Per bug #17561 from Egor Chindyaskin.  The given test case crashes
    in all supported branches (and probably a lot further back),
    so patch all.
    
    Discussion: https://postgr.es/m/17561-80350151b9ad2ad4@postgresql.org


 src/backend/parser/parse_expr.c | 9 +++++++++
 src/backend/parser/parse_node.c | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 197c432dd41..d30fc1301c8 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -15,6 +15,7 @@
 
 #include "postgres.h"
 
+#include "access/htup_details.h"
 #include "catalog/pg_type.h"
 #include "commands/dbcommands.h"
 #include "miscadmin.h"
@@ -2176,6 +2177,14 @@ transformRowExpr(ParseState *pstate, RowExpr *r, bool allowDefault)
 	newr->args = transformExpressionList(pstate, r->args,
 										 pstate->p_expr_kind, allowDefault);
 
+	/* Disallow more columns than will fit in a tuple */
+	if (list_length(newr->args) > MaxTupleAttributeNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_TOO_MANY_COLUMNS),
+				 errmsg("ROW expressions can have at most %d entries",
+						MaxTupleAttributeNumber),
+				 parser_errposition(pstate, r->location)));
+
 	/* Barring later casting, we consider the type RECORD */
 	newr->row_typeid = RECORDOID;
 	newr->row_format = COERCE_IMPLICIT_CAST;
diff --git a/src/backend/parser/parse_node.c b/src/backend/parser/parse_node.c
index 6dbad53a410..25a3edb8243 100644
--- a/src/backend/parser/parse_node.c
+++ b/src/backend/parser/parse_node.c
@@ -83,7 +83,7 @@ free_parsestate(ParseState *pstate)
 	 */
 	if (pstate->p_next_resno - 1 > MaxTupleAttributeNumber)
 		ereport(ERROR,
-				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				(errcode(ERRCODE_TOO_MANY_COLUMNS),
 				 errmsg("target lists can have at most %d entries",
 						MaxTupleAttributeNumber)));
 


[parent: 6ffaf75a8001]