Commit: patch 9.0.2010: [security] use-after-free from buf_contents_changed()

[Christian Brabandt]

patch 9.0.2010: [security] use-after-free from buf_contents_changed()

Commit: https://github.com/vim/vim/commit/41e6f7d6ba67b61d911f9b1d76325cd79224753d
Author: Christian Brabandt <c...@256bit.org>
Date: Wed Oct 11 21:08:13 2023 +0200

patch 9.0.2010: [security] use-after-free from buf_contents_changed()

Problem: [security] use-after-free from buf_contents_changed()
Solution: block autocommands

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

diff --git a/src/buffer.c b/src/buffer.c
index 93f9245f2..9ee74f54d 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -6013,6 +6013,9 @@ buf_contents_changed(buf_T *buf)
return TRUE;
}

+ // We don't want to trigger autocommands now, they may have nasty
+ // side-effects like wiping buffers
+ block_autocmds();
if (ml_open(curbuf) == OK
&& readfile(buf->b_ffname, buf->b_fname,
(linenr_T)0, (linenr_T)0, (linenr_T)MAXLNUM,
@@ -6038,6 +6041,8 @@ buf_contents_changed(buf_T *buf)
if (curbuf != newbuf) // safety check
wipe_buffer(newbuf, FALSE);

+ unblock_autocmds();
+
return differ;
}

diff --git a/src/testdir/crash/editing_arg_idx_POC_1 b/src/testdir/crash/editing_arg_idx_POC_1
new file mode 100644
index 0000000000000000000000000000000000000000..5d048d03405a31e268f30950dc11d9dc767103de
GIT binary patch
literal 398
zcmZwD!Ait15C-6Q&0W2Yy>wf2DbmwYi}(amL<%CBO(xw!n=DDn_NF)A!FTfFOZWty
z*Th|sivKAC^TU_ny6>4fIaACu7b(;@t_>8u7Pjng+-^-{OUeeP;cAc-GI4DXQos=-
zt0I`seSs-4iwd?JWEmwu<s;Ogk%sVIJn$7$4R)<vF_TcvI<hgXL)msXyNhdw*2#Tt
ze;zWS04Q27GKPM$;@US}&lmYZzd=RFGqr7(DU0x;O`nk`Ki^~u$HM=`mWO}T2fu1U
zlnB!1b0_5=lf3(B2ZaeV4^WQ|ggm}Kje{-z59-)b1yhyL&H9q6oKMbtJUO#pJlb!6
E0fTvuc>n+a

literal 0
HcmV?d00001

diff --git a/src/testdir/test_crash.vim b/src/testdir/test_crash.vim
index 9a80340c2..5cd07e2a3 100644
--- a/src/testdir/test_crash.vim
+++ b/src/testdir/test_crash.vim
@@ -78,6 +78,14 @@ func Test_crash1()
\ ' && echo "crash 9: [OK]" >> X_crash1_result.txt' .. "\<cr>")
call TermWait(buf, 1000)

+ let file = 'crash/editing_arg_idx_POC_1'
+ let args = printf(cmn_args, vim, file)
+ call term_sendkeys(buf, args ..
+ \ ' || echo "crash 10: [OK]" >> X_crash1_result.txt' .. "\<cr>")
+ call TermWait(buf, 1000)
+ call delete('Xerr')
+ call delete('@')
+
" clean up
exe buf .. "bw!"

@@ -93,6 +101,7 @@ func Test_crash1()
\ 'crash 7: [OK]',
\ 'crash 8: [OK]',
\ 'crash 9: [OK]',
+ \ 'crash 10: [OK]',
\ ]

call assert_equal(expected, getline(1, '$'))
diff --git a/src/version.c b/src/version.c
index 458b46a37..0479f2096 100644
--- a/src/version.c
+++ b/src/version.c
@@ -704,6 +704,8 @@ static char *(features[]) =

static int included_patches[] =
{ /* Add new patch number below this line */
+/**/
+ 2010,
/**/
2009,
/**/