[PATCH 5.17 641/772] ext4: fix memory leak in parse_apply_sb_mount_options()

Greg Kroah-Hartman
2022-06-07T21:39:02Z

From: Eric Biggers <ebiggers@google.com>

commit c069db76ed7b681c69159f44be96d2137e9ca989 upstream.

If processing the on-disk mount options fails after any memory was
allocated in the ext4_fs_context, e.g. s_qf_names, then this memory is
leaked. Fix this by calling ext4_fc_free() instead of kfree() directly.

Reproducer:

mkfs.ext4 -F /dev/vdc
tune2fs /dev/vdc -E mount_opts=usrjquota=file
echo clear > /sys/kernel/debug/kmemleak
mount /dev/vdc /vdc
echo scan > /sys/kernel/debug/kmemleak
sleep 5
echo scan > /sys/kernel/debug/kmemleak
cat /sys/kernel/debug/kmemleak

Fixes: 7edfd85b1ffd ("ext4: Completely separate options parsing and sb setup")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20220513231605.175121-2-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ext4/super.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2626,8 +2626,10 @@ parse_failed:
ret = ext4_apply_options(fc, sb);

out_free:
- kfree(s_ctx);
- kfree(fc);
+ if (fc) {
+ ext4_fc_free(fc);
+ kfree(fc);
+ }
kfree(s_mount_opts);
return ret;
}