From ba516fb0715c75b1b2d393c3de7b99fca6a1ac67 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 13 Aug 2022 15:21:28 -0400 Subject: [PATCH] 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 7e9216142a..0a0d68f0e7 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -1066,6 +1066,9 @@ 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 */