From 2e8cfcf4ea1140213eae56ce64a2c53182643578 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 2 Oct 2015 15:00:51 -0400
Subject: [PATCH] Add recursion depth protection to LIKE matching.

Since MatchText() recurses, it could in principle be driven to stack
overflow, although quite a long pattern would be needed.
---
 src/backend/utils/adt/like.c       | 1 +
 src/backend/utils/adt/like_match.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
index 284c5aeb886..b6db4f3b018 100644
--- a/src/backend/utils/adt/like.c
+++ b/src/backend/utils/adt/like.c
@@ -21,6 +21,7 @@
 
 #include "catalog/pg_collation.h"
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
 #include "utils/builtins.h"
 #include "utils/pg_locale.h"
 
diff --git a/src/backend/utils/adt/like_match.c b/src/backend/utils/adt/like_match.c
index 3ec24872d00..83ece28722c 100644
--- a/src/backend/utils/adt/like_match.c
+++ b/src/backend/utils/adt/like_match.c
@@ -83,6 +83,9 @@ 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
-- 
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