From 8a0bbe7b8aad6f8da28dee218c01bc8a0185a2d5 Mon Sep 17 00:00:00 2001
From: Christian Brabandt <cb@256bit.org>
Date: Thu, 1 Aug 2024 20:16:51 +0200
Subject: [PATCH] patch 9.1.0647: [security] use-after-free in
 tagstack_clear_entry

Problem:  [security] use-after-free in tagstack_clear_entry
          (Suyue Guo )
Solution: Instead of manually calling vim_free() on each of the tagstack
          entries, let's use tagstack_clear_entry(), which will
          also free the stack, but using the VIM_CLEAR macro,
          which prevents a use-after-free by setting those pointers
          to NULL

This addresses CVE-2024-41957

Github advisory:
https://github.com/vim/vim/security/advisories/GHSA-f9cr-gv85-hcr4

Signed-off-by: Christian Brabandt <cb@256bit.org>
---
 src/window.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/window.c b/src/window.c
index 7ca29d46a..70c72bca7 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5661,10 +5661,7 @@ win_free(
     win_free_lsize(wp);
 
     for (i = 0; i < wp->w_tagstacklen; ++i)
-    {
-	vim_free(wp->w_tagstack[i].tagname);
-	vim_free(wp->w_tagstack[i].user_data);
-    }
+	tagstack_clear_entry(&wp->w_tagstack[i]);
     vim_free(wp->w_localdir);
     vim_free(wp->w_prevdir);
 
-- 
2.33.0