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 <m...@redhat.com>
Signed-off-by: Jason Wang <jasow...@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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