From 6af359ef4cc3c221e0e3102ab2b54cf64d7c9835 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Fri, 2 Aug 2024 06:00:02 +0800
Subject: [PATCH] vim-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

https://github.com/vim/vim/commit/8a0bbe7b8aad6f8da28dee218c01bc8a0185a2d5

Co-authored-by: Christian Brabandt <cb@256bit.org>
---
 src/nvim/window.c                     |   4 ++--
 test/functional/legacy/crash_spec.lua |  19 +++++++++++++++++++
 test/old/testdir/crash/double_free    | Bin 0 -> 561 bytes
 test/old/testdir/test_crash.vim       |   6 ++++++
 4 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 test/old/testdir/crash/double_free

diff --git a/src/nvim/window.c b/src/nvim/window.c
index b770f0ccab..4fde200a01 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -73,6 +73,7 @@
 #include "nvim/statusline.h"
 #include "nvim/strings.h"
 #include "nvim/syntax.h"
+#include "nvim/tag.h"
 #include "nvim/terminal.h"
 #include "nvim/types_defs.h"
 #include "nvim/ui.h"
@@ -5205,8 +5206,7 @@ void win_free(win_T *wp, tabpage_T *tp)
   xfree(wp->w_lines);
 
   for (int i = 0; i < wp->w_tagstacklen; i++) {
-    xfree(wp->w_tagstack[i].tagname);
-    xfree(wp->w_tagstack[i].user_data);
+    tagstack_clear_entry(&wp->w_tagstack[i]);
   }
 
   xfree(wp->w_localdir);
diff --git a/test/functional/legacy/crash_spec.lua b/test/functional/legacy/crash_spec.lua
index 04f77c7d4f..e72c3a512a 100644
--- a/test/functional/legacy/crash_spec.lua
+++ b/test/functional/legacy/crash_spec.lua
@@ -1,8 +1,12 @@
+local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
 local assert_alive = n.assert_alive
 local clear = n.clear
 local command = n.command
+local eq = t.eq
+local eval = n.eval
+local exec = n.exec
 local feed = n.feed
 
 before_each(clear)
@@ -32,3 +36,18 @@ it('no crash with very long option error message', function()
   pcall(command, 'source test/old/testdir/crash/poc_did_set_langmap')
   assert_alive()
 end)
+
+it('no crash when closing window with tag in loclist', function()
+  exec([[
+    new
+    lexpr ['foo']
+    lopen
+    let g:qf_bufnr = bufnr()
+    lclose
+    call settagstack(1, #{items: [#{tagname: 'foo', from: [g:qf_bufnr, 1, 1, 0]}]})
+  ]])
+  eq(1, eval('bufexists(g:qf_bufnr)'))
+  command('1close')
+  eq(0, eval('bufexists(g:qf_bufnr)'))
+  assert_alive()
+end)
diff --git a/test/old/testdir/crash/double_free b/test/old/testdir/crash/double_free
new file mode 100644
index 0000000000000000000000000000000000000000..895c4a04b6ab1c2eabc80a486e52cabd7a99a5ea
GIT binary patch
literal 561
zcmYeaV`LDsE#(T%%TeM=%;VOzPN?BxU|?X3j)-w`a&qFz%V$X8VqmEM50}l$F-cD4
zN-W9X%J<6is9<1V;L0h>{Qv*Ip02L0r>Cc<k^)0jRX`O4*qX&;q$;=u1x4qVmc%C~
zF)*0LWE67c<QFg$bERaar4@4}7Nw^$FflL`$8hE47v<{e>K1Tu=9la1>pLrOCFf@r
zbCp7MWGHYYm8PW_CZ!mL$0RZ2+2<xgRq88niHV7M6{XANrMOmPmKbI#Ggxw!WL1l%
zOyDY!;z}y#(n(c_<>KPvDlaceENDp1&rH?eR7p)p(ACvdaEZ|<=HmA(=Mrrw<|>Vm
zDQ1F&1y_gw$a}fzMX3deDJj*()rJaFGKx|aQd6pnixd=WQNjQJ42eD<Z-gi2NEjL#
z8Wvjlb0*p`GSB}1pTVWPC^f;hnyWM~M=38A6!ahw1qFq?1lv-OsL2x(2q^k*TN;y+
zSmd6QS)5|63j*Mf{m;O{z`&4m@IM4JFe<o|JNLL2Rg{$k<)xN$m2)vPFfxF}f|MBY
zIv9Mo^ok2|>QlIi3sM!;>$nn26%~p>L0(gnnyk>8-jXCGP+rPB<^TV@%nB<NB{K&G
XPkw%`T15!3fKVVZzqG*CmMaeco!qIG

literal 0
HcmV?d00001

diff --git a/test/old/testdir/test_crash.vim b/test/old/testdir/test_crash.vim
index fd786e5d54..29061aa423 100644
--- a/test/old/testdir/test_crash.vim
+++ b/test/old/testdir/test_crash.vim
@@ -190,6 +190,12 @@ func Test_crash1_3()
   call term_sendkeys(buf, args)
   call TermWait(buf, 150)
 
+  let file = 'crash/double_free'
+  let cmn_args = "%s -u NONE -i NONE -n -e -s -S %s -c ':qa!'\<cr>"
+  let args = printf(cmn_args, vim, file)
+  call term_sendkeys(buf, args)
+  call TermWait(buf, 50)
+
   " clean up
   exe buf .. "bw!"
   bw!