[Qemu-devel] [PATCH for 2.3 1/2] virtio-net: validate backend queue numbers against bus limitation

[Qemu-devel] [PATCH for 2.3 1/2] virtio-net: validate backend queue numbers against bus limitation

[Jason Wang]

We don't validate the backend queue numbers against bus limitation,
this will easily crash qemu if it exceeds the limitation. 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>
---
 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

[Qemu-devel] [PATCH for 2.3 2/2] virtio-net: fix the upper bound when trying to delete queues

[Jason Wang]

Virtqueue were indexed from zero, so don't delete virtqueue whose
index is n->max_queues * 2 + 1.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: qemu-stable <qemu-stable@nongnu.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/virtio-net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 59f76bc..b6fac9c 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1309,7 +1309,7 @@ static void virtio_net_set_multiqueue(VirtIONet *n, int multiqueue)
 
     n->multiqueue = multiqueue;
 
-    for (i = 2; i <= n->max_queues * 2 + 1; i++) {
+    for (i = 2; i < n->max_queues * 2 + 1; i++) {
         virtio_del_queue(vdev, i);
     }
 
-- 
2.1.0

Re: [Qemu-devel] [PATCH for 2.3 1/2] virtio-net: validate backend queue numbers against bus limitation

[Michael S. Tsirkin]

On Thu, Mar 19, 2015 at 03:05:51PM +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. Fixing this
> by doing the validation and fail early.

Can you please include the qemu command line that crashes?

> Cc: qemu-stable <qemu-stable@nongnu.org>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  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

Re: [Qemu-devel] [PATCH for 2.3 2/2] virtio-net: fix the upper bound when trying to delete queues

[Michael S. Tsirkin]

On Thu, Mar 19, 2015 at 03:05:52PM +0800, Jason Wang wrote:
> Virtqueue were indexed from zero, so don't delete virtqueue whose
> index is n->max_queues * 2 + 1.

But what's the current behaviour?
Can it lead to aborts? virtio_del_queue does:
    if (n < 0 || n >= VIRTIO_PCI_QUEUE_MAX) {
        abort();
    }


> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: qemu-stable <qemu-stable@nongnu.org>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  hw/net/virtio-net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 59f76bc..b6fac9c 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1309,7 +1309,7 @@ static void virtio_net_set_multiqueue(VirtIONet *n, int multiqueue)
>  
>      n->multiqueue = multiqueue;
>  
> -    for (i = 2; i <= n->max_queues * 2 + 1; i++) {
> +    for (i = 2; i < n->max_queues * 2 + 1; i++) {
>          virtio_del_queue(vdev, i);
>      }
>  
> -- 
> 2.1.0

Re: [Qemu-devel] [PATCH for 2.3 1/2] virtio-net: validate backend queue numbers against bus limitation

[Jason Wang]

On Thu, Mar 19, 2015 at 6:10 PM, Michael S. Tsirkin <mst@redhat.com> 
wrote:
> On Thu, Mar 19, 2015 at 03:05:51PM +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. Fixing 
>> this
>>  by doing the validation and fail early.
> 
> Can you please include the qemu command line that crashes?

Ok, will include it in v2. cli is something like:

qemu-system-x86_64 -netdev tap,id=hn0,queues=256 -device 
virtio-net-pci,netdev=hn0 -enable-kvm

Re: [Qemu-devel] [PATCH for 2.3 2/2] virtio-net: fix the upper bound when trying to delete queues

[Jason Wang]

On Thu, Mar 19, 2015 at 6:12 PM, Michael S. Tsirkin <mst@redhat.com> 
wrote:
> On Thu, Mar 19, 2015 at 03:05:52PM +0800, Jason Wang wrote:
>>  Virtqueue were indexed from zero, so don't delete virtqueue whose
>>  index is n->max_queues * 2 + 1.
> 
> But what's the current behaviour?
> 
> Can it lead to aborts? virtio_del_queue does:
>     if (n < 0 || n >= VIRTIO_PCI_QUEUE_MAX) {
>         abort();
>     }

Yes, it will hit abort() above.
> 
> 
> 
>>  Cc: Michael S. Tsirkin <mst@redhat.com>
>>  Cc: qemu-stable <qemu-stable@nongnu.org>
>>  Signed-off-by: Jason Wang <jasowang@redhat.com>
>>  ---
>>   hw/net/virtio-net.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>  
>>  diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>>  index 59f76bc..b6fac9c 100644
>>  --- a/hw/net/virtio-net.c
>>  +++ b/hw/net/virtio-net.c
>>  @@ -1309,7 +1309,7 @@ static void 
>> virtio_net_set_multiqueue(VirtIONet *n, int multiqueue)
>>   
>>       n->multiqueue = multiqueue;
>>   
>>  -    for (i = 2; i <= n->max_queues * 2 + 1; i++) {
>>  +    for (i = 2; i < n->max_queues * 2 + 1; i++) {
>>           virtio_del_queue(vdev, i);
>>       }
>>   
>>  -- 
>>  2.1.0
> 

Re: [Qemu-devel] [PATCH for 2.3 2/2] virtio-net: fix the upper bound when trying to delete queues

[Jason Wang]

On Fri, Mar 20, 2015 at 1:53 PM, Jason Wang <jasowang@redhat.com> wrote:
> 
> 
> On Thu, Mar 19, 2015 at 6:12 PM, Michael S. Tsirkin <mst@redhat.com> 
> wrote:
>> On Thu, Mar 19, 2015 at 03:05:52PM +0800, Jason Wang wrote:
>>>  Virtqueue were indexed from zero, so don't delete virtqueue whose
>>>  index is n->max_queues * 2 + 1.
>> 
>> But what's the current behaviour?
>> 
>> Can it lead to aborts? virtio_del_queue does:
>>     if (n < 0 || n >= VIRTIO_PCI_QUEUE_MAX) {
>>         abort();
>>     }
> 
> Yes, it will hit abort() above.

With patch 1/1 on top, there will be no crash. Will drop this from V2. 
This patch was only needed for more virtio queues series.

> 
>> 
>> 
>> 
>>>  Cc: Michael S. Tsirkin <mst@redhat.com>
>>>  Cc: qemu-stable <qemu-stable@nongnu.org>
>>>  Signed-off-by: Jason Wang <jasowang@redhat.com>
>>>  ---
>>>   hw/net/virtio-net.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>   diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>>>  index 59f76bc..b6fac9c 100644
>>>  --- a/hw/net/virtio-net.c
>>>  +++ b/hw/net/virtio-net.c
>>>  @@ -1309,7 +1309,7 @@ static void 
>>> virtio_net_set_multiqueue(VirtIONet *n, int multiqueue)
>>>         n->multiqueue = multiqueue;
>>>    -    for (i = 2; i <= n->max_queues * 2 + 1; i++) {
>>>  +    for (i = 2; i < n->max_queues * 2 + 1; i++) {
>>>           virtio_del_queue(vdev, i);
>>>       }
>>>    --  2.1.0
>> 
>