[PATCH for 3.10-stable] virtio-net: drop NETIF_F_FRAGLIST

[PATCH for 3.10-stable] virtio-net: drop NETIF_F_FRAGLIST

[Sheng Yong]

From: Jason Wang <jasowang@redhat.com>

commit 48900cb6af4282fa0fb6ff4d72a81aa3dadb5c39 upstream.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 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 2835bfe..b5d1152 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1545,9 +1545,9 @@ 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
-- 
1.8.3.4

Re: [PATCH for 3.10-stable] virtio-net: drop NETIF_F_FRAGLIST

[Greg KH]

On Tue, Oct 27, 2015 at 01:50:53AM +0000, Sheng Yong wrote:
> From: Jason Wang <jasowang@redhat.com>
> 
> commit 48900cb6af4282fa0fb6ff4d72a81aa3dadb5c39 upstream.
> 
> 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>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
>  drivers/net/virtio_net.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

This patch isn't in any stable tree, why just add it to 3.10?  What
about all of the other ones?

thanks,

greg k-h

Re: [PATCH for 3.10-stable] virtio-net: drop NETIF_F_FRAGLIST

[Sheng Yong]

On 11/7/2015 2:55 AM, Greg KH wrote:
> On Tue, Oct 27, 2015 at 01:50:53AM +0000, Sheng Yong wrote:
>> From: Jason Wang <jasowang@redhat.com>
>>
>> commit 48900cb6af4282fa0fb6ff4d72a81aa3dadb5c39 upstream.
>>
>> 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>
>> Signed-off-by: David S. Miller <davem@davemloft.net>
>> ---
>>  drivers/net/virtio_net.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> This patch isn't in any stable tree, why just add it to 3.10?  What
> about all of the other ones?

Hi, Greg

This patch addresses CVE-2015-5156. I didn't check if other stables added
this patch. 3.4.y, 3.14.y and 4.1.y can have this patch directly by cherry-pick.

thanks,
Sheng
> 
> thanks,
> 
> greg k-h
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> 

Re: [PATCH for 3.10-stable] virtio-net: drop NETIF_F_FRAGLIST

[Jiri Slaby]

On 11/06/2015, 07:55 PM, Greg KH wrote:
> On Tue, Oct 27, 2015 at 01:50:53AM +0000, Sheng Yong wrote:
>> From: Jason Wang <jasowang@redhat.com>
>>
>> commit 48900cb6af4282fa0fb6ff4d72a81aa3dadb5c39 upstream.
>>
>> 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>
>> Signed-off-by: David S. Miller <davem@davemloft.net>
>> ---
>>  drivers/net/virtio_net.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> This patch isn't in any stable tree, why just add it to 3.10?  What
> about all of the other ones?

This was now submitted by David in NETWORKING patches for >= 3.18. So I
applied it to 3.12.

thanks,
-- 
js
suse labs