vrf: Reset IPCB/IP6CB when processing outbound pkts in vrf dev xmit

ssuryaextr · kuba-moo · commit ee201011c1e1 · 2021-12-01T19:03:13.000-08:00
IPCB/IP6CB need to be initialized when processing outbound v4 or v6 pkts in the codepath of vrf device xmit function so that leftover garbage doesn't cause futher code that uses the CB to incorrectly process the pkt. One occasion of the issue might occur when MPLS route uses the vrf device as the outgoing device such as when the route is added using "ip -f mpls route add <label> dev <vrf>" command. The problems seems to exist since day one. Hence I put the day one commits on the Fixes tags. Fixes: 193125d ("net: Introduce VRF device driver") Fixes: 35402e3 ("net: Add IPv6 support to VRF device") Cc: stable@vger.kernel.org Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20211130162637.3249-1-ssuryaextr@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
@@ -497,6 +497,7 @@ static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
 	/* strip the ethernet header added for pass through VRF device */
 	__skb_pull(skb, skb_network_offset(skb));
 
+	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 	ret = vrf_ip6_local_out(net, skb->sk, skb);
 	if (unlikely(net_xmit_eval(ret)))
 		dev->stats.tx_errors++;
@@ -579,6 +580,7 @@ static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb,
 					       RT_SCOPE_LINK);
 	}
 
+	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 	ret = vrf_ip_local_out(dev_net(skb_dst(skb)->dev), skb->sk, skb);
 	if (unlikely(net_xmit_eval(ret)))
 		vrf_dev->stats.tx_errors++;
