From fae09422fdb97ef2bfbfffcd2abc30060a9c1f51 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 11 Nov 2012 19:56:27 -0500 Subject: [PATCH] Check for stack overflow in transformSetOperationTree(). Since transformSetOperationTree() recurses, it can be driven to stack overflow with enough UNION/INTERSECT/EXCEPT clauses in a query. Add a check to ensure it fails cleanly instead of crashing. Per report from Matthew Gerber (though it's not clear whether this is the only thing going wrong for him). Historical note: I think the reasoning behind not putting a check here in the beginning was that the check in transformExpr() ought to be sufficient to guard the whole parser. However, because transformSetOperationTree() recurses all the way to the bottom of the set-operation tree before doing any analysis of the statement's expressions, that check doesn't save it. --- src/backend/parser/analyze.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index efc11a29d6..8d5e6dfea2 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -26,6 +26,7 @@ #include "access/sysattr.h" #include "catalog/pg_type.h" +#include "miscadmin.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "optimizer/var.h" @@ -1380,6 +1381,9 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, Assert(stmt && IsA(stmt, SelectStmt)); + /* Guard against stack overflow due to overly complex set-expressions */ + check_stack_depth(); + /* * Validity-check both leaf and internal SELECTs for disallowed ops. */ -- 2.40.0