This is a note to let you know that I've just added the patch titled
ntfs: add check for mft record size in superblock
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ntfs-add-check-for-mft-record-size-in-superblock.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 90489325d9af45cae11665d53dd34e7e1e7fccf4
Author: Rustam Kovhaev <rkovhaev@xxxxxxxxx>
Date: Tue Oct 13 16:48:17 2020 -0700
ntfs: add check for mft record size in superblock
[ Upstream commit 4f8c94022f0bc3babd0a124c0a7dcdd7547bd94e ]
Number of bytes allocated for mft record should be equal to the mft record
size stored in ntfs superblock as reported by syzbot, userspace might
trigger out-of-bounds read by dereferencing ctx->attr in ntfs_attr_find()
Reported-by: syzbot+aed06913f36eff9b544e@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Rustam Kovhaev <rkovhaev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Tested-by: syzbot+aed06913f36eff9b544e@xxxxxxxxxxxxxxxxxxxxxxxxx
Acked-by: Anton Altaparmakov <anton@xxxxxxxxxx>
Link: https://syzkaller.appspot.com/bug?extid=aed06913f36eff9b544e
Link: https://lkml.kernel.org/r/20200824022804.226242-1-rkovhaev@xxxxxxxxx
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index d284f07eda775..38260c07de8b5 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -1844,6 +1844,12 @@ int ntfs_read_inode_mount(struct inode *vi)
brelse(bh);
}
+ if (le32_to_cpu(m->bytes_allocated) != vol->mft_record_size) {
+ ntfs_error(sb, "Incorrect mft record size %u in superblock, should be %u.",
+ le32_to_cpu(m->bytes_allocated), vol->mft_record_size);
+ goto err_out;
+ }
+
/* Apply the mst fixups. */
if (post_read_mst_fixup((NTFS_RECORD*)m, vol->mft_record_size)) {
/* FIXME: Try to use the $MFTMirr now. */
