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virtio-net: drop NETIF_F_FRAGLIST

linux 3.14-stable Charles (Chas) Williams 1 participant 1 message Sep 29, 2015

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Networking Network drivers virtio net driver
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Charles (Chas) Williams

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From: Jason Wang <[email protected]>

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.

Fixes CVE-2015-5156.

Cc Michael S. Tsirkin <[email protected]>
Signed-off-by Jason Wang <[email protected]>
Acked-by Michael S. Tsirkin <[email protected]>
Signed-off-by David S. Miller <[email protected]>
Signed-off-by Chas Williams <[email protected]>
---
 drivers/net/virtio_net.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/net/virtio_net.c +2 -2
index 841b608..5c150a0 100644
@@ -1652,9 +1652,9 @@ 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
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