Add stack depth checks to key recursive functions in backend/nodes/*.c.

tglsfdc · tglsfdc · commit 0f9fd7419a19 · 2018-12-10T11:12:43.000-05:00
Although copyfuncs.c has a check_stack_depth call in its recursion, equalfuncs.c, outfuncs.c, and readfuncs.c lacked one. This seems unwise. Likewise fix planstate_tree_walker(), in branches where that exists. Discussion: https://postgr.es/m/30253.1544286631@sss.pgh.pa.us
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
@@ -29,6 +29,7 @@
 
 #include "postgres.h"
 
+#include "miscadmin.h"
 #include "nodes/extensible.h"
 #include "nodes/relation.h"
 #include "utils/datum.h"
@@ -2732,6 +2733,9 @@ equal(const void *a, const void *b)
 	if (nodeTag(a) != nodeTag(b))
 		return false;
 
+	/* Guard against stack overflow due to overly complex expressions */
+	check_stack_depth();
+
 	switch (nodeTag(a))
 	{
 			/*
diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
@@ -3623,6 +3623,9 @@ planstate_tree_walker(PlanState *planstate,
 	Plan	   *plan = planstate->plan;
 	ListCell   *lc;
 
+	/* Guard against stack overflow due to overly complex plan trees */
+	check_stack_depth();
+
 	/* initPlan-s */
 	if (planstate_walk_subplans(planstate->initPlan, walker, context))
 		return true;
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
@@ -26,6 +26,7 @@
 #include <ctype.h>
 
 #include "lib/stringinfo.h"
+#include "miscadmin.h"
 #include "nodes/extensible.h"
 #include "nodes/plannodes.h"
 #include "nodes/relation.h"
@@ -3276,6 +3277,9 @@ _outForeignKeyCacheInfo(StringInfo str, const ForeignKeyCacheInfo *node)
 void
 outNode(StringInfo str, const void *obj)
 {
+	/* Guard against stack overflow due to overly complex expressions */
+	check_stack_depth();
+
 	if (obj == NULL)
 		appendStringInfoString(str, "<>");
 	else if (IsA(obj, List) ||IsA(obj, IntList) || IsA(obj, OidList))
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
@@ -29,6 +29,7 @@
 #include <math.h>
 
 #include "fmgr.h"
+#include "miscadmin.h"
 #include "nodes/extensible.h"
 #include "nodes/parsenodes.h"
 #include "nodes/plannodes.h"
@@ -2262,6 +2263,9 @@ parseNodeString(void)
 
 	READ_TEMP_LOCALS();
 
+	/* Guard against stack overflow due to overly complex expressions */
+	check_stack_depth();
+
 	token = pg_strtok(&length);
 
 #define MATCH(tokname, namelen) \
