From 09a2dd453007f9c7205274623acdd73747c22d64 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Fri, 7 Apr 2023 11:49:27 +0200
Subject: [PATCH] [CVE-2023-29469] Hashing of empty dict strings isn't
 deterministic

When hashing empty strings which aren't null-terminated,
xmlDictComputeFastKey could produce inconsistent results. This could
lead to various logic or memory errors, including double frees.

For consistency the seed is also taken into account, but this shouldn't
have an impact on security.

Found by OSS-Fuzz.

Fixes #510.
---
 dict.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dict.c b/dict.c
index 26ce516d..57b76fae 100644
--- a/dict.c
+++ b/dict.c
@@ -451,7 +451,8 @@ static unsigned long
 xmlDictComputeFastKey(const xmlChar *name, int namelen, int seed) {
     unsigned long value = seed;
 
-    if (name == NULL) return(0);
+    if ((name == NULL) || (namelen <= 0))
+        return(value);
     value += *name;
     value <<= 5;
     if (namelen > 10) {
-- 
2.27.0

