[PATCH 4.14 094/146] openvswitch: Fix pop_vlan action for double tagged frames

Greg Kroah-Hartman
2018-01-01T14:58:10Z

From: Eric Garver <e@erig.me>

[ Upstream commit c48e74736fccf25fb32bb015426359e1c2016e3b ]

skb_vlan_pop() expects skb->protocol to be a valid TPID for double
tagged frames. So set skb->protocol to the TPID and let skb_vlan_pop()
shift the true ethertype into position for us.

Fixes: 5108bbaddc37 ("openvswitch: add processing of L3 packets")
Signed-off-by: Eric Garver <e@erig.me>
Reviewed-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/openvswitch/flow.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -532,6 +532,7 @@ static int key_extract(struct sk_buff *s
return -EINVAL;

skb_reset_network_header(skb);
+ key->eth.type = skb->protocol;
} else {
eth = eth_hdr(skb);
ether_addr_copy(key->eth.src, eth->h_source);
@@ -545,15 +546,23 @@ static int key_extract(struct sk_buff *s
if (unlikely(parse_vlan(skb, key)))
return -ENOMEM;

- skb->protocol = parse_ethertype(skb);
- if (unlikely(skb->protocol == htons(0)))
+ key->eth.type = parse_ethertype(skb);
+ if (unlikely(key->eth.type == htons(0)))
return -ENOMEM;

+ /* Multiple tagged packets need to retain TPID to satisfy
+ * skb_vlan_pop(), which will later shift the ethertype into
+ * skb->protocol.
+ */
+ if (key->eth.cvlan.tci & htons(VLAN_TAG_PRESENT))
+ skb->protocol = key->eth.cvlan.tpid;
+ else
+ skb->protocol = key->eth.type;
+
skb_reset_network_header(skb);
__skb_push(skb, skb->data - skb_mac_header(skb));
}
skb_reset_mac_len(skb);
- key->eth.type = skb->protocol;

/* Network layer. */
if (key->eth.type == htons(ETH_P_IP)) {