qemu: supplementary fix of CVE-2016-5403
It is reported in qemu community that VM always exits with: | 2016-10-17T07:33:40.393592Z qemu-kvm: Virtqueue size exceede when VM is suspend and resume. Solution from the maintainer of virtio is to merge following 3 commits: http://git.qemu.org/?p=qemu.git;a=commit;h=bccdef6 http://git.qemu.org/?p=qemu.git;a=commit;h=58a83c6 http://git.qemu.org/?p=qemu.git;a=commit;h=4b7f91e The first 2 commits have been merged in qemu 2.7.0. Then apply the third one. (From OE-Core rev: db5b9254fbbc30e50b50c7c8cd1f04dcc965cd52) Signed-off-by: Kai Kang <kai.kang@windriver.com> Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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@ -0,0 +1,57 @@
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Upstream-Status: Backport
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Supplementary fix of CVE-2016-5403 which is backported from:
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http://git.qemu.org/?p=qemu.git;a=commit;h=4b7f91e
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Signed-off-by: Kai Kang <kai.kang@windriver.com>
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---
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From 4b7f91ed0270a371e1933efa21ba600b6da23ab9 Mon Sep 17 00:00:00 2001
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From: Stefan Hajnoczi <stefanha@redhat.com>
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Date: Wed, 7 Sep 2016 11:51:25 -0400
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Subject: [PATCH] virtio: zero vq->inuse in virtio_reset()
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vq->inuse must be zeroed upon device reset like most other virtqueue
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fields.
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In theory, virtio_reset() just needs assert(vq->inuse == 0) since
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devices must clean up in-flight requests during reset (requests cannot
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not be leaked!).
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In practice, it is difficult to achieve vq->inuse == 0 across reset
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because balloon, blk, 9p, etc implement various different strategies for
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cleaning up requests. Most devices call g_free(elem) directly without
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telling virtio.c that the VirtQueueElement is cleaned up. Therefore
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vq->inuse is not decremented during reset.
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This patch zeroes vq->inuse and trusts that devices are not leaking
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VirtQueueElements across reset.
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I will send a follow-up series that refactors request life-cycle across
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all devices and converts vq->inuse = 0 into assert(vq->inuse == 0) but
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this more invasive approach is not appropriate for stable trees.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Cc: qemu-stable <qemu-stable@nongnu.org>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Reviewed-by: Ladi Prosek <lprosek@redhat.com>
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---
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hw/virtio/virtio.c | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
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index 74c085c..e8a13a5 100644
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--- a/hw/virtio/virtio.c
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+++ b/hw/virtio/virtio.c
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@@ -822,6 +822,7 @@ void virtio_reset(void *opaque)
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vdev->vq[i].signalled_used_valid = false;
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vdev->vq[i].notification = true;
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vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
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+ vdev->vq[i].inuse = 0;
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}
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}
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--
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2.9.3
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@ -9,6 +9,7 @@ SRC_URI += "file://configure-fix-Darwin-target-detection.patch \
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file://no-valgrind.patch \
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file://pathlimit.patch \
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file://qemu-2.5.0-cflags.patch \
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file://0001-virtio-zero-vq-inuse-in-virtio_reset.patch \
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"
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SRC_URI_prepend = "http://wiki.qemu-project.org/download/${BP}.tar.bz2"
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