Fuzzing of 5.10 stable branch shows NULL pointer dereference happens in lbmStartIO() on log->bdev pointer. The reason for bdev being NULL is the JFS_NOINTEGRITY flag is set on mount of this fs. When this flag is enabled, it results in the open_dummy_log function being called, which initializes a new dummy_log, but does not assign a value to bdev.
The error is fixed in 5.18 by commit 07888c665b405b1cd3577ddebfeb74f4717a84c4. Backport of this commit is too intrusive, so it is more reasonable to apply a small patch to fix this issue.
Found by Linux Verification Center (linuxtesting.org) with syzkaller.
Signed-off-by: Mikhail Ukhin mish.uxin2012@yandex.ru Signed-off-by: Mikhail Ivanov iwanov-23@bk.ru Signed-off-by: Pavel Koshutin koshutin.pavel@yandex.ru Signed-off-by: Artem Sadovnikov ancowi69@gmail.com --- fs/jfs/jfs_logmgr.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c index 78fd136ac13b..d6f0fea96ba1 100644 --- a/fs/jfs/jfs_logmgr.c +++ b/fs/jfs/jfs_logmgr.c @@ -1983,7 +1983,8 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp) bio = bio_alloc(GFP_NOFS, 1);
bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9); - bio_set_dev(bio, log->bdev); + if (log->bdev != NULL) + bio_set_dev(bio, log->bdev);
bio_add_page(bio, bp->l_page, LOGPSIZE, bp->l_offset); BUG_ON(bio->bi_iter.bi_size != LOGPSIZE); @@ -2127,7 +2128,8 @@ static void lbmStartIO(struct lbuf * bp)
bio = bio_alloc(GFP_NOFS, 1); bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9); - bio_set_dev(bio, log->bdev); + if (log->bdev != NULL) + bio_set_dev(bio, log->bdev);
bio_add_page(bio, bp->l_page, LOGPSIZE, bp->l_offset); BUG_ON(bio->bi_iter.bi_size != LOGPSIZE);
Hi,
Thanks for your patch.
FYI: kernel test robot notices the stable kernel rule is not satisfied.
The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#opti...
Rule: The upstream commit ID must be specified with a separate line above the commit text. Subject: [PATCH 5.10/5.15] jfs: add check if log->bdev is NULL in lbmStartIO() Link: https://lore.kernel.org/stable/20240112165007.4764-1-mish.uxin2012%40yandex....
Please ignore this mail if the patch is not relevant for upstream.
On Fri, Jan 12, 2024 at 07:50:07PM +0300, Mikhail Ukhin wrote:
Fuzzing of 5.10 stable branch shows NULL pointer dereference happens in lbmStartIO() on log->bdev pointer. The reason for bdev being NULL is the JFS_NOINTEGRITY flag is set on mount of this fs. When this flag is enabled, it results in the open_dummy_log function being called, which initializes a new dummy_log, but does not assign a value to bdev.
The error is fixed in 5.18 by commit 07888c665b405b1cd3577ddebfeb74f4717a84c4. Backport of this commit is too intrusive, so it is more reasonable to apply a small patch to fix this issue.
Found by Linux Verification Center (linuxtesting.org) with syzkaller.
Signed-off-by: Mikhail Ukhin mish.uxin2012@yandex.ru Signed-off-by: Mikhail Ivanov iwanov-23@bk.ru Signed-off-by: Pavel Koshutin koshutin.pavel@yandex.ru Signed-off-by: Artem Sadovnikov ancowi69@gmail.com
fs/jfs/jfs_logmgr.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
Who is using jfs in 5.10 and 5.15? Why not just mark the filesystem as BROKEN there instead? If you need to access your ancient filesystem image just use a newer kernel.
For filesystems that are not used in older kernels, work like this feels odd, especially for something just like a NULL dereference which doesn't do much, right?
thanks,
greg k-h
On Fri, Jan 12, 2024 at 08:31:30PM +0100, Greg Kroah-Hartman wrote:
On Fri, Jan 12, 2024 at 07:50:07PM +0300, Mikhail Ukhin wrote:
Fuzzing of 5.10 stable branch shows NULL pointer dereference happens in lbmStartIO() on log->bdev pointer. The reason for bdev being NULL is the JFS_NOINTEGRITY flag is set on mount of this fs. When this flag is enabled, it results in the open_dummy_log function being called, which initializes a new dummy_log, but does not assign a value to bdev.
The error is fixed in 5.18 by commit 07888c665b405b1cd3577ddebfeb74f4717a84c4. Backport of this commit is too intrusive, so it is more reasonable to apply a small patch to fix this issue.
Found by Linux Verification Center (linuxtesting.org) with syzkaller.
Signed-off-by: Mikhail Ukhin mish.uxin2012@yandex.ru Signed-off-by: Mikhail Ivanov iwanov-23@bk.ru Signed-off-by: Pavel Koshutin koshutin.pavel@yandex.ru Signed-off-by: Artem Sadovnikov ancowi69@gmail.com
fs/jfs/jfs_logmgr.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
Who is using jfs in 5.10 and 5.15? Why not just mark the filesystem as BROKEN there instead? If you need to access your ancient filesystem image just use a newer kernel.
For filesystems that are not used in older kernels, work like this feels odd, especially for something just like a NULL dereference which doesn't do much, right?
Now dropped from my review queue due to lack of response...
linux-stable-mirror@lists.linaro.org
-
Greg Kroah-Hartman -
kernel test robot -
Mikhail Ukhin