patch 9.1.0678: [security]: use-after-free in alist_add()

Problem:  [security]: use-after-free in alist_add()
          (SuyueGuo)
Solution: Lock the current window, so that the reference to
          the argument list remains valid.

This fixes CVE-2024-43374

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_arglist.vim

@@ -359,6 +359,7 @@ func Test_argv()
   call assert_equal('', argv(1, 100))
   call assert_equal([], argv(-1, 100))
   call assert_equal('', argv(10, -1))
+  %argdelete
 endfunc
 
 " Test for the :argedit command
@@ -744,4 +745,26 @@ func Test_all_command()
   %bw!
 endfunc
 
+" Test for deleting buffer when creating an arglist. This was accessing freed
+" memory
+func Test_crash_arglist_uaf()
+  "%argdelete
+  new one
+  au BufAdd XUAFlocal :bw
+  "call assert_fails(':arglocal XUAFlocal', 'E163:')
+  arglocal XUAFlocal
+  au! BufAdd
+  bw! XUAFlocal
+
+  au BufAdd XUAFlocal2 :bw
+  new two
+  new three
+  arglocal
+  argadd XUAFlocal2 Xfoobar
+  bw! XUAFlocal2
+  bw! two
+
+  au! BufAdd
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab