ptr_ring: wrap back ->producer in __ptr_ring_swap_queue()
authorCong Wang <xiyou.wangcong@gmail.com>
Sun, 30 Dec 2018 20:43:42 +0000 (12:43 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 9 Jan 2019 16:38:33 +0000 (17:38 +0100)
commit6e36567284cf05217d67dfeb49161bb33ce16363
treed2e97d3359ca955b04102aa3e0b2e7ff35a20819
parent4037ce1b28ca94b5b7952b3887777805197cb348
ptr_ring: wrap back ->producer in __ptr_ring_swap_queue()

[ Upstream commit aff6db454599d62191aabc208930e891748e4322 ]

__ptr_ring_swap_queue() tries to move pointers from the old
ring to the new one, but it forgets to check if ->producer
is beyond the new size at the end of the operation. This leads
to an out-of-bound access in __ptr_ring_produce() as reported
by syzbot.

Reported-by: syzbot+8993c0fa96d57c399735@syzkaller.appspotmail.com
Fixes: 5d49de532002 ("ptr_ring: resize support")
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
include/linux/ptr_ring.h