postgres.git / summary / log / commit / refs

commit    b744e13b021712d4aae3c239e8aedefc463c755f
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Sat Aug 13 19:21:28 2022 +0000
First released in: 16.0, 10.23, 11.18, 12.13, 13.9, 14.6, 15.0

    Catch stack overflow when recursing in transformFromClauseItem().
    
    Most parts of the parser can expect that the stack overflow check
    in transformExprRecurse() will trigger before things get desperate.
    However, transformFromClauseItem() can recurse directly to self
    without having analyzed any expressions, so it's possible to drive
    it to a stack-overrun crash.  Add a check to prevent that.
    
    Per bug #17583 from Egor Chindyaskin.  Back-patch to all supported
    branches.
    
    Richard Guo
    
    Discussion: https://postgr.es/m/17583-33be55b9f981f75c@postgresql.org


 src/backend/parser/parse_clause.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 361c4c78864..e3106a72187 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -1106,6 +1106,9 @@ transformFromClauseItem(ParseState *pstate, Node *n,
 						RangeTblEntry **top_rte, int *top_rti,
 						List **namespace)
 {
+	/* Guard against stack overflow due to overly deep subtree */
+	check_stack_depth();
+
 	if (IsA(n, RangeVar))
 	{
 		/* Plain relation reference, or perhaps a CTE reference */


[parent: db9ec28d6416]