postgres.git / summary / log / commit / refs

commit    496ab1d6c8d853899595e986f04cd70c4b13dac4
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Sat Aug 13 19:21:28 2022 +0000

    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 2763af9470e..b5a984ad14b 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -1054,6 +1054,9 @@ transformFromClauseItem(ParseState *pstate, Node *n,
 						ParseNamespaceItem **top_nsitem,
 						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: 2db574a2184e]