* [Qemu-devel] [PATCH for 2.3 V2] virtio-net: validate backend queue numbers against bus limitation
@ 2015-03-20 6:07 Jason Wang
2015-03-23 13:20 ` Stefan Hajnoczi
0 siblings, 1 reply; 3+ messages in thread
From: Jason Wang @ 2015-03-20 6:07 UTC (permalink / raw)
To: qemu-devel; +Cc: Jason Wang, qemu-stable, mst
We don't validate the backend queue numbers against bus limitation,
this will easily crash qemu if it exceeds the limitation which will
hit the abort() in virtio_del_queue(). An example is trying to
starting a virtio-net device with 256 queues. E.g:
./qemu-system-x86_64 -netdev tap,id=hn0,queues=256 -device
virtio-net-pci,netdev=hn0
Fixing this by doing the validation and fail early.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: qemu-stable <qemu-stable@nongnu.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
Changes from V1:
Tweak the commit log.
---
hw/net/virtio-net.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 27adcc5..59f76bc 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1588,6 +1588,13 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
n->max_queues = MAX(n->nic_conf.peers.queues, 1);
+ if (n->max_queues * 2 + 1 > VIRTIO_PCI_QUEUE_MAX) {
+ error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
+ "must be a postive integer less than %d.",
+ n->max_queues, (VIRTIO_PCI_QUEUE_MAX - 1) / 2);
+ virtio_cleanup(vdev);
+ return;
+ }
n->vqs = g_malloc0(sizeof(VirtIONetQueue) * n->max_queues);
n->vqs[0].rx_vq = virtio_add_queue(vdev, 256, virtio_net_handle_rx);
n->curr_queues = 1;
--
2.1.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH for 2.3 V2] virtio-net: validate backend queue numbers against bus limitation
2015-03-20 6:07 [Qemu-devel] [PATCH for 2.3 V2] virtio-net: validate backend queue numbers against bus limitation Jason Wang
@ 2015-03-23 13:20 ` Stefan Hajnoczi
2015-03-23 13:51 ` Michael S. Tsirkin
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Hajnoczi @ 2015-03-23 13:20 UTC (permalink / raw)
To: Jason Wang; +Cc: mst, qemu-devel, qemu-stable
[-- Attachment #1: Type: text/plain, Size: 1986 bytes --]
On Fri, Mar 20, 2015 at 02:07:50PM +0800, Jason Wang wrote:
> We don't validate the backend queue numbers against bus limitation,
> this will easily crash qemu if it exceeds the limitation which will
> hit the abort() in virtio_del_queue(). An example is trying to
> starting a virtio-net device with 256 queues. E.g:
>
> ./qemu-system-x86_64 -netdev tap,id=hn0,queues=256 -device
> virtio-net-pci,netdev=hn0
>
> Fixing this by doing the validation and fail early.
>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: qemu-stable <qemu-stable@nongnu.org>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> Changes from V1:
> Tweak the commit log.
> ---
> hw/net/virtio-net.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 27adcc5..59f76bc 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1588,6 +1588,13 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
> virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
>
> n->max_queues = MAX(n->nic_conf.peers.queues, 1);
> + if (n->max_queues * 2 + 1 > VIRTIO_PCI_QUEUE_MAX) {
> + error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
> + "must be a postive integer less than %d.",
> + n->max_queues, (VIRTIO_PCI_QUEUE_MAX - 1) / 2);
> + virtio_cleanup(vdev);
> + return;
> + }
If VIRTIO_PCI_QUEUE_MAX is really PCI-only then this is a layering
violation. Virtio devices should not assume a particular transport
(PCI, CCW, etc).
Either the constant should be renamed if it truly applies to all
transports, or there should be a virtio_get_max_queues() function that
lets the transport pick a value.
That said, virtio-scsi.c already checks VIRTIO_PCI_QUEUE_MAX so maybe
this patch is fine and a cleanup should be written later:
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH for 2.3 V2] virtio-net: validate backend queue numbers against bus limitation
2015-03-23 13:20 ` Stefan Hajnoczi
@ 2015-03-23 13:51 ` Michael S. Tsirkin
0 siblings, 0 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2015-03-23 13:51 UTC (permalink / raw)
To: Stefan Hajnoczi; +Cc: Jason Wang, qemu-devel, qemu-stable
On Mon, Mar 23, 2015 at 01:20:28PM +0000, Stefan Hajnoczi wrote:
> On Fri, Mar 20, 2015 at 02:07:50PM +0800, Jason Wang wrote:
> > We don't validate the backend queue numbers against bus limitation,
> > this will easily crash qemu if it exceeds the limitation which will
> > hit the abort() in virtio_del_queue(). An example is trying to
> > starting a virtio-net device with 256 queues. E.g:
> >
> > ./qemu-system-x86_64 -netdev tap,id=hn0,queues=256 -device
> > virtio-net-pci,netdev=hn0
> >
> > Fixing this by doing the validation and fail early.
> >
> > Cc: Michael S. Tsirkin <mst@redhat.com>
> > Cc: qemu-stable <qemu-stable@nongnu.org>
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> > Changes from V1:
> > Tweak the commit log.
> > ---
> > hw/net/virtio-net.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index 27adcc5..59f76bc 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -1588,6 +1588,13 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
> > virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
> >
> > n->max_queues = MAX(n->nic_conf.peers.queues, 1);
> > + if (n->max_queues * 2 + 1 > VIRTIO_PCI_QUEUE_MAX) {
> > + error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
> > + "must be a postive integer less than %d.",
> > + n->max_queues, (VIRTIO_PCI_QUEUE_MAX - 1) / 2);
> > + virtio_cleanup(vdev);
> > + return;
> > + }
>
> If VIRTIO_PCI_QUEUE_MAX is really PCI-only then this is a layering
> violation. Virtio devices should not assume a particular transport
> (PCI, CCW, etc).
>
> Either the constant should be renamed if it truly applies to all
> transports, or there should be a virtio_get_max_queues() function that
> lets the transport pick a value.
>
> That said, virtio-scsi.c already checks VIRTIO_PCI_QUEUE_MAX so maybe
> this patch is fine and a cleanup should be written later:
>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Yes, we need to rename this constant, no problem here.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-03-20 6:07 [Qemu-devel] [PATCH for 2.3 V2] virtio-net: validate backend queue numbers against bus limitation Jason Wang
2015-03-23 13:20 ` Stefan Hajnoczi
2015-03-23 13:51 ` Michael S. Tsirkin
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