linux-kernel - [PATCH] virtio: fix out of range array access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100225171340.GA16141@redhat.com>
Date:	Thu, 25 Feb 2010 19:13:41 +0200
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Rusty Russell <rusty@...tcorp.com.au>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Anthony Liguori <aliguori@...ibm.com>,
	Shirley Ma <xma@...ibm.com>, Amit Shah <amit.shah@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] virtio: fix out of range array access

I have observed the following error on virtio-net module unload:

------------[ cut here ]------------
WARNING: at kernel/irq/manage.c:858 __free_irq+0xa0/0x14c()
Hardware name: Bochs
Trying to free already-free IRQ 0
Modules linked in: virtio_net(-) virtio_blk virtio_pci virtio_ring
virtio af_packet e1000 shpchp aacraid uhci_hcd ohci_hcd ehci_hcd [last
unloaded: scsi_wait_scan]
Pid: 1957, comm: rmmod Not tainted 2.6.33-rc8-vhost #24
Call Trace:
 [<ffffffff8103e195>] warn_slowpath_common+0x7c/0x94
 [<ffffffff8103e204>] warn_slowpath_fmt+0x41/0x43
 [<ffffffff810a7a36>] ? __free_pages+0x5a/0x70
 [<ffffffff8107cc00>] __free_irq+0xa0/0x14c
 [<ffffffff8107cceb>] free_irq+0x3f/0x65
 [<ffffffffa0081424>] vp_del_vqs+0x81/0xb1 [virtio_pci]
 [<ffffffffa0091d29>] virtnet_remove+0xda/0x10b [virtio_net]
 [<ffffffffa0075200>] virtio_dev_remove+0x22/0x4a [virtio]
 [<ffffffff812709ee>] __device_release_driver+0x66/0xac
 [<ffffffff81270ab7>] driver_detach+0x83/0xa9
 [<ffffffff8126fc66>] bus_remove_driver+0x91/0xb4
 [<ffffffff81270fcf>] driver_unregister+0x6c/0x74
 [<ffffffffa0075418>] unregister_virtio_driver+0xe/0x10 [virtio]
 [<ffffffffa0091c4d>] fini+0x15/0x17 [virtio_net]
 [<ffffffff8106997b>] sys_delete_module+0x1c3/0x230
 [<ffffffff81007465>] ? old_ich_force_enable_hpet+0x117/0x164
 [<ffffffff813bb720>] ? do_page_fault+0x29c/0x2cc
 [<ffffffff81028e58>] sysenter_dispatch+0x7/0x27
---[ end trace 15e88e4c576cc62b ]---

The bug is in virtio-pci: we use msix_vector as array index to get irq
entry, but some vqs do not have a dedicated vector so this causes an out
of bounds access.  By chance, we seem to often get 0 value, which
results in this error.

Fix by verifying that vector is legal before using it as index.

Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
---
Shirley, Amit, with Rusty on vacation, need other reviewers.  Could you
please review the following patch and ack on list if appropriate?

 drivers/virtio/virtio_pci.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 28d9cf7..7127bfe 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -473,7 +473,8 @@ static void vp_del_vqs(struct virtio_device *vdev)
 
 	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
 		info = vq->priv;
-		if (vp_dev->per_vq_vectors)
+		if (vp_dev->per_vq_vectors &&
+			info->msix_vector != VIRTIO_MSI_NO_VECTOR)
 			free_irq(vp_dev->msix_entries[info->msix_vector].vector,
 				 vq);
 		vp_del_vq(vq);
-- 
1.7.0.18.g0d53a5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/