genhd: check for int overflow in disk_expand_part_tbl()
authorJens Axboe <axboe@fb.com>
Wed, 19 Nov 2014 20:06:22 +0000 (13:06 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 16 Jan 2015 14:59:02 +0000 (06:59 -0800)
commitdd4fb6fc5dd2e85e65222f0e5e1e321dec9fc2b7
tree9ad743249381d5460cbcc1cc0e98d20af0aa0f48
parentedefe2069bc0d8ab1fd03dd9b141cbfec98aca8f
genhd: check for int overflow in disk_expand_part_tbl()

commit 5fabcb4c33fe11c7e3afdf805fde26c1a54d0953 upstream.

We can get here from blkdev_ioctl() -> blkpg_ioctl() -> add_partition()
with a user passed in partno value. If we pass in 0x7fffffff, the
new target in disk_expand_part_tbl() overflows the 'int' and we
access beyond the end of ptbl->part[] and even write to it when we
do the rcu_assign_pointer() to assign the new partition.

Reported-by: David Ramos <daramos@stanford.edu>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block/genhd.c