[PATCH 5.10 08/23] ntfs: check for valid standard information attribute

Greg Kroah-Hartman
2021-02-25T10:13:29Z

From: Rustam Kovhaev <rkovhaev@gmail.com>

commit 4dfe6bd94959222e18d512bdf15f6bf9edb9c27c upstream.

Mounting a corrupted filesystem with NTFS resulted in a kernel crash.

We should check for valid STANDARD_INFORMATION attribute offset and length
before trying to access it

Link: https://lkml.kernel.org/r/20210217155930.1506815-1-rkovhaev@gmail.com
Link: https://syzkaller.appspot.com/bug?extid=c584225dabdea2f71969
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Reported-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Tested-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ntfs/inode.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -629,6 +629,12 @@ static int ntfs_read_locked_inode(struct
}
a = ctx->attr;
/* Get the standard information attribute value. */
+ if ((u8 *)a + le16_to_cpu(a->data.resident.value_offset)
+ + le32_to_cpu(a->data.resident.value_length) >
+ (u8 *)ctx->mrec + vol->mft_record_size) {
+ ntfs_error(vi->i_sb, "Corrupt standard information attribute in inode.");
+ goto unm_err_out;
+ }
si = (STANDARD_INFORMATION*)((u8*)a +
le16_to_cpu(a->data.resident.value_offset));