block: fix an integer overflow in logical block size
authorMikulas Patocka <mpatocka@redhat.com>
Wed, 15 Jan 2020 13:35:25 +0000 (08:35 -0500)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 23 Jan 2020 07:21:29 +0000 (08:21 +0100)
commita7f79052d1afc2a80a81f45e15e0d741ba15dc2b
tree3291d16dad1b9bc4c43b9b61cb6da834289753ed
parent8d9fd1f4aee052b031b9cc03a645991ab190b2cc
block: fix an integer overflow in logical block size

commit ad6bf88a6c19a39fb3b0045d78ea880325dfcf15 upstream.

Logical block size has type unsigned short. That means that it can be at
most 32768. However, there are architectures that can run with 64k pages
(for example arm64) and on these architectures, it may be possible to
create block devices with 64k block size.

For exmaple (run this on an architecture with 64k pages):

Mount will fail with this error because it tries to read the superblock using 2-sector
access:
  device-mapper: writecache: I/O is not aligned, sector 2, size 1024, block size 65536
  EXT4-fs (dm-0): unable to read superblock

This patch changes the logical block size from unsigned short to unsigned
int to avoid the overflow.

Cc: stable@vger.kernel.org
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block/blk-settings.c
drivers/md/dm-snap-persistent.c
drivers/md/raid0.c
include/linux/blkdev.h