From: Jens Axboe <axboe@fb.com>
Date: Wed, 19 Nov 2014 20:06:22 +0000 (-0700)
Subject: genhd: check for int overflow in disk_expand_part_tbl()
X-Git-Tag: v3.2.67~135
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=44cee4aa677c9cc2a48d2bdde8928115e06cb9a0;p=pandora-kernel.git

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: Ben Hutchings <ben@decadent.org.uk>
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