[net] virtio-net: drop NETIF_F_FRAGLIST
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Message ID 1438682145-25986-1-git-send-email-jasowang@redhat.com
State New, archived
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  • [net] virtio-net: drop NETIF_F_FRAGLIST
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Commit Message

Jason Wang Aug. 4, 2015, 9:55 a.m. UTC
virtio declares support for NETIF_F_FRAGLIST, but assumes
that there are at most MAX_SKB_FRAGS + 2 fragments which isn't
always true with a fraglist.

A longer fraglist in the skb will make the call to skb_to_sgvec overflow
the sg array, leading to memory corruption.

Drop NETIF_F_FRAGLIST so we only get what we can handle.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
The patch is needed for stable.
---
 drivers/net/virtio_net.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Michael S. Tsirkin Aug. 4, 2015, 10:05 a.m. UTC | #1
On Tue, Aug 04, 2015 at 05:55:45PM +0800, Jason Wang wrote:
> virtio declares support for NETIF_F_FRAGLIST, but assumes
> that there are at most MAX_SKB_FRAGS + 2 fragments which isn't
> always true with a fraglist.
> 
> A longer fraglist in the skb will make the call to skb_to_sgvec overflow
> the sg array, leading to memory corruption.
> 
> Drop NETIF_F_FRAGLIST so we only get what we can handle.
> 
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

Especially important now that virtio_net: add gro capability
was merged for net-next, making bridged setups create fraglists.

> ---
> The patch is needed for stable.
> ---
>  drivers/net/virtio_net.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 7fbca37..2347a73 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1756,9 +1756,9 @@ static int virtnet_probe(struct virtio_device *vdev)
>  	/* Do we support "hardware" checksums? */
>  	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
>  		/* This opens up the world of extra features. */
> -		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
> +		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG;
>  		if (csum)
> -			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
> +			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG;
>  
>  		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
>  			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
> -- 
> 2.1.4
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Sergei Shtylyov Aug. 4, 2015, 11:11 a.m. UTC | #2
Hello.

On 8/4/2015 12:55 PM, Jason Wang wrote:

> virtio declares support for NETIF_F_FRAGLIST, but assumes
> that there are at most MAX_SKB_FRAGS + 2 fragments which isn't
> always true with a fraglist.

> A longer fraglist in the skb will make the call to skb_to_sgvec overflow
> the sg array, leading to memory corruption.

> Drop NETIF_F_FRAGLIST so we only get what we can handle.

> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> The patch is needed for stable.
> ---
>   drivers/net/virtio_net.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 7fbca37..2347a73 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1756,9 +1756,9 @@ static int virtnet_probe(struct virtio_device *vdev)
>   	/* Do we support "hardware" checksums? */
>   	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
>   		/* This opens up the world of extra features. */
> -		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
> +		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG;
>   		if (csum)
> -			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
> +			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG;

    I'd have added spaces around | to match the style seen below.

>   		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
>   			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO

MBR, Sergei

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Jason Wang Aug. 5, 2015, 2:32 a.m. UTC | #3
On 08/04/2015 07:11 PM, Sergei Shtylyov wrote:
> Hello.
>
> On 8/4/2015 12:55 PM, Jason Wang wrote:
>
>> virtio declares support for NETIF_F_FRAGLIST, but assumes
>> that there are at most MAX_SKB_FRAGS + 2 fragments which isn't
>> always true with a fraglist.
>
>> A longer fraglist in the skb will make the call to skb_to_sgvec overflow
>> the sg array, leading to memory corruption.
>
>> Drop NETIF_F_FRAGLIST so we only get what we can handle.
>
>> Cc: Michael S. Tsirkin <mst@redhat.com>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>> The patch is needed for stable.
>> ---
>>   drivers/net/virtio_net.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 7fbca37..2347a73 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -1756,9 +1756,9 @@ static int virtnet_probe(struct virtio_device
>> *vdev)
>>       /* Do we support "hardware" checksums? */
>>       if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
>>           /* This opens up the world of extra features. */
>> -        dev->hw_features |=
>> NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
>> +        dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG;
>>           if (csum)
>> -            dev->features |=
>> NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
>> +            dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG;
>
>    I'd have added spaces around | to match the style seen below.
>

Ok, will fix this in V2.

>>           if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
>>               dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
>
> MBR, Sergei
>

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Patch
diff mbox series

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7fbca37..2347a73 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1756,9 +1756,9 @@  static int virtnet_probe(struct virtio_device *vdev)
 	/* Do we support "hardware" checksums? */
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 		/* This opens up the world of extra features. */
-		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG;
 		if (csum)
-			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG;
 
 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO