[PATCH 4.4 161/190] virtio_net: check return value of skb_to_sgvec always

From: Greg Kroah-Hartman
Date: Wed Apr 11 2018 - 16:26:40 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jason A. Donenfeld <Jason@xxxxxxxxx>

commit e2fcad58fd230f635a74e4e983c6f4ea893642d2 upstream.

Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[natechancellor: backport to 4.4]
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -858,7 +858,7 @@ static int xmit_skb(struct send_queue *s
struct virtio_net_hdr_mrg_rxbuf *hdr;
const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
struct virtnet_info *vi = sq->vq->vdev->priv;
- unsigned num_sg;
+ int num_sg;
unsigned hdr_len = vi->hdr_len;
bool can_push;

@@ -911,11 +911,16 @@ static int xmit_skb(struct send_queue *s
if (can_push) {
__skb_push(skb, hdr_len);
num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
+ if (unlikely(num_sg < 0))
+ return num_sg;
/* Pull header back to avoid skew in tx bytes calculations. */
__skb_pull(skb, hdr_len);
} else {
sg_set_buf(sq->sg, hdr, hdr_len);
- num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
+ num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len);
+ if (unlikely(num_sg < 0))
+ return num_sg;
+ num_sg++;
}
return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
}