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authorWillem de Bruijn <willemb@google.com>2020-03-09 11:34:35 -0400
committerDavid S. Miller <davem@davemloft.net>2020-03-11 23:12:16 -0700
commit46e4c421a053c36bf7a33dda2272481bcaf3eed3 (patch)
tree76c4e9db0d24d3027cff0ecfc537d0e8ab373d74 /net
parentf3cc008bf6d59b8d93b4190e01d3e557b0040e15 (diff)
downloadlinux-46e4c421a053c36bf7a33dda2272481bcaf3eed3.tar.gz
net/packet: tpacket_rcv: do not increment ring index on drop
In one error case, tpacket_rcv drops packets after incrementing the
ring producer index.

If this happens, it does not update tp_status to TP_STATUS_USER and
thus the reader is stalled for an iteration of the ring, causing out
of order arrival.

The only such error path is when virtio_net_hdr_from_skb fails due
to encountering an unknown GSO type.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/packet/af_packet.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 30c6879d6774..e5b0986215d2 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2274,6 +2274,13 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 					TP_STATUS_KERNEL, (macoff+snaplen));
 	if (!h.raw)
 		goto drop_n_account;
+
+	if (do_vnet &&
+	    virtio_net_hdr_from_skb(skb, h.raw + macoff -
+				    sizeof(struct virtio_net_hdr),
+				    vio_le(), true, 0))
+		goto drop_n_account;
+
 	if (po->tp_version <= TPACKET_V2) {
 		packet_increment_rx_head(po, &po->rx_ring);
 	/*
@@ -2286,12 +2293,6 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 			status |= TP_STATUS_LOSING;
 	}
 
-	if (do_vnet &&
-	    virtio_net_hdr_from_skb(skb, h.raw + macoff -
-				    sizeof(struct virtio_net_hdr),
-				    vio_le(), true, 0))
-		goto drop_n_account;
-
 	po->stats.stats1.tp_packets++;
 	if (copy_skb) {
 		status |= TP_STATUS_COPY;