virtio_pci: fix out of bound access for msix_names
authorJason Wang <jasowang@redhat.com>
Thu, 23 Mar 2017 05:07:16 +0000 (13:07 +0800)
committerMichael S. Tsirkin <mst@redhat.com>
Tue, 28 Mar 2017 17:40:53 +0000 (20:40 +0300)
commitde85ec8b07f82c8c84de7687f769e74bf4c26a1e
tree72ce8462675d94d2e82723dc84583f644c5e190d
parentc02ed2e75ef4c74e41e421acb4ef1494671585e8
virtio_pci: fix out of bound access for msix_names

Fedora has received multiple reports of crashes when running
4.11 as a guest

https://bugzilla.redhat.com/show_bug.cgi?id=1430297
https://bugzilla.redhat.com/show_bug.cgi?id=1434462
https://bugzilla.kernel.org/show_bug.cgi?id=194911
https://bugzilla.redhat.com/show_bug.cgi?id=1433899

The crashes are not always consistent but they are generally
some flavor of oops or GPF in virtio related code. Multiple people
have done bisections (Thank you Thorsten Leemhuis and
Richard W.M. Jones) and found this commit to be at fault

07ec51480b5eb1233f8c1b0f5d7a7c8d1247c507 is the first bad commit
commit 07ec51480b5eb1233f8c1b0f5d7a7c8d1247c507
Author: Christoph Hellwig <hch@lst.de>
Date:   Sun Feb 5 18:15:19 2017 +0100

    virtio_pci: use shared interrupts for virtqueues

The issue seems to be an out of bounds access to the msix_names
array corrupting kernel memory.

Fixes: 07ec51480b5e ("virtio_pci: use shared interrupts for virtqueues")
Reported-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
drivers/virtio/virtio_pci_common.c