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>
diff --git a/src/window.c b/src/window.c
index 7ca29d4..70c72bc 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5837,10 +5837,7 @@
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);