[PATCH net] virtio-net: drop NETIF_F_FRAGLIST

From: Jason Wang <jasowang@redhat.com>
To: virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: mst@redhat.com, Jason Wang <jasowang@redhat.com>
Subject: [PATCH net] virtio-net: drop NETIF_F_FRAGLIST
Date: Tue,  4 Aug 2015 17:55:45 +0800	[thread overview]
Message-ID: <1438682145-25986-1-git-send-email-jasowang@redhat.com> (raw)

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;
 
 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
-- 
2.1.4

