patch 9.0.1969: [security] buffer-overflow in trunc_string()
Commit:
https://github.com/vim/vim/commit/3bd7fa12e146c6051490d048a4acbfba974eeb04
Author: Christian Brabandt <[email protected]>
Date: Mon Oct 2 20:59:08 2023 +0200
patch 9.0.1969: [security] buffer-overflow in trunc_string()
Problem: buffer-overflow in trunc_string()
Solution: Add NULL at end of buffer
Currently trunc_string() assumes that when the string is too long,
buf[e-1] will always be writeable. But that assumption may not always be
true. The condition currently looks like this
else if (e + 3 < buflen)
[...]
else
{
// can't fit in the "...", just truncate it
buf[e - 1] = NUL;
}
but this means, we may run into the last else clause with e still being
larger than buflen. So a buffer overflow occurs.
So instead of using `buf[e - 1]`, let's just always
truncate at `buf[buflen - 1]` which should always be writable.
Signed-off-by: Christian Brabandt <[email protected]>
diff --git a/src/message.c b/src/message.c
index 2fc6cefa9..83c8b4f4a 100644
--- a/src/message.c
+++ b/src/message.c
@@ -353,7 +353,7 @@ trunc_string(
else
{
// can't fit in the "...", just truncate it
- buf[e - 1] = NUL;
+ buf[buflen - 1] = NUL;
}
}
diff --git a/src/testdir/test_crash.vim b/src/testdir/test_crash.vim
index a1da68ed4..5c83e3a2f 100644
--- a/src/testdir/test_crash.vim
+++ b/src/testdir/test_crash.vim
@@ -66,6 +66,12 @@ func Test_crash1()
\ ' && echo "crash 7: [OK]" >> X_crash1_result.txt' .. "\<cr>")
call TermWait(buf, 3000)
+ let file = 'crash/vim_msg_trunc_poc'
+ let args = printf(cmn_args, vim, file)
+ call term_sendkeys(buf, args ..
+ \ ' || echo "crash 8: [OK]" >> X_crash1_result.txt' .. "\<cr>")
+ call TermWait(buf, 3000)
+
" clean up
exe buf .. "bw!"
@@ -79,6 +85,7 @@ func Test_crash1()
\ 'crash 5: [OK]',
\ 'crash 6: [OK]',
\ 'crash 7: [OK]',
+ \ 'crash 8: [OK]',
\ ]
call assert_equal(expected, getline(1, '$'))
diff --git a/src/version.c b/src/version.c
index 1be146276..3056f35d7 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 */
+/**/
+ 1969,
/**/
1968,
/**/
--
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