fs/ntfs3: Fix slab-out-of-bounds read in ntfs_trim_fs

[ Upstream commit 557d19675a ]

Syzbot reports an out of bound access in ntfs_trim_fs.
The cause of this is using a loop termination condition that compares
window index (iw) with wnd->nbits instead of wnd->nwnd, due to which the
index used for wnd->free_bits exceeds the size of the array allocated.

Fix the loop condition.

Fixes: 3f3b442b5a ("fs/ntfs3: Add bitmap")
Link: https://syzkaller.appspot.com/bug?extid=b892240eac461e488d51
Reported-by: syzbot+b892240eac461e488d51@syzkaller.appspotmail.com
Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Abdun Nihaal 2022-10-01 12:30:24 +05:30 committed by Greg Kroah-Hartman
parent 1ba0968b33
commit ab53749c32

View file

@ -1432,7 +1432,7 @@ int ntfs_trim_fs(struct ntfs_sb_info *sbi, struct fstrim_range *range)
down_read_nested(&wnd->rw_lock, BITMAP_MUTEX_CLUSTERS);
for (; iw < wnd->nbits; iw++, wbit = 0) {
for (; iw < wnd->nwnd; iw++, wbit = 0) {
CLST lcn_wnd = iw * wbits;
struct buffer_head *bh;