Add recursion depth protection to LIKE matching.

tglsfdc · tglsfdc · commit b875ca09f362 · 2015-10-02T15:00:52.000-04:00
Since MatchText() recurses, it could in principle be driven to stack
overflow, although quite a long pattern would be needed.
diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
@@ -20,6 +20,7 @@
 #include <ctype.h>
 
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
 #include "utils/builtins.h"
 
 
diff --git a/src/backend/utils/adt/like_match.c b/src/backend/utils/adt/like_match.c
@@ -82,6 +82,9 @@ MatchText(char *t, int tlen, char *p, int plen)
 	if (plen == 1 && *p == '%')
 		return LIKE_TRUE;
 
+	/* Since this function recurses, it could be driven to stack overflow */
+	check_stack_depth();
+
 	/*
 	 * In this loop, we advance by char when matching wildcards (and thus on
 	 * recursive entry to this function we are properly char-synced). On other
