From a40db8fde759261b042138646da36c632a739f31 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.

Incorporates change from commit
09a2dd453007f9c7205274623acdd73747c22d64.
---
 dict.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dict.c b/dict.c
index 0ef3718d..5e84cfca 100644
--- a/dict.c
+++ b/dict.c
@@ -444,8 +444,9 @@ static unsigned long
 xmlDictComputeFastKey(const xmlChar *name, int namelen, int seed) {
     unsigned long value = seed;
 
-    if (name == NULL) return(0);
-    value = *name;
+    if ((name == NULL) || (namelen <= 0))
+        return(value);
+    value += *name;
     value <<= 5;
     if (namelen > 10) {
         value += name[namelen - 1];
-- 
2.41.0