From: Tom Lane Date: Mon, 12 Nov 2012 00:56:10 +0000 (-0500) Subject: Check for stack overflow in transformSetOperationTree(). X-Git-Tag: REL9_3_BETA1~727 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=34f3b396a6554903007031b0541781b7ecdd6e4d;p=postgresql 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. --- diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index 823d3b445a..7085035c52 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" @@ -1487,6 +1488,9 @@ 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. */