Commit ad819276 authored by Mahesh Bandewar's avatar Mahesh Bandewar Committed by David S. Miller
Browse files

ipvlan: don't deref eth hdr before checking it's set 



IPvlan in L3 mode discards outbound multicast packets but performs
the check before ensuring the ether-header is set or not. This is
an error that Eric found through code browsing.

Fixes: 2ad7bf36 (“ipvlan: Initial check-in of the IPVLAN driver.”)
Signed-off-by: default avatarMahesh Bandewar <maheshb@google.com>
Reported-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4b1bd9db

drivers/net/ipvlan/ipvlan_core.c

+10 −8
Original line number Diff line number Diff line
@@ -498,19 +498,21 @@ static int ipvlan_process_outbound(struct sk_buff *skb) 
	struct ethhdr *ethh = eth_hdr(skb);

	int ret = NET_XMIT_DROP;



	/* In this mode we dont care about multicast and broadcast traffic */

	/* The ipvlan is a pseudo-L2 device, so the packets that we receive

	 * will have L2; which need to discarded and processed further

	 * in the net-ns of the main-device.

	 */

	if (skb_mac_header_was_set(skb)) {

		/* In this mode we dont care about

		 * multicast and broadcast traffic */

		if (is_multicast_ether_addr(ethh->h_dest)) {

		pr_debug_ratelimited("Dropped {multi|broad}cast of type=[%x]\n",

			pr_debug_ratelimited(

				"Dropped {multi|broad}cast of type=[%x]\n",

				ntohs(skb->protocol));

			kfree_skb(skb);

			goto out;

		}



	/* The ipvlan is a pseudo-L2 device, so the packets that we receive

	 * will have L2; which need to discarded and processed further

	 * in the net-ns of the main-device.

	 */

	if (skb_mac_header_was_set(skb)) {

		skb_pull(skb, sizeof(*ethh));

		skb->mac_header = (typeof(skb->mac_header))~0U;

		skb_reset_network_header(skb);

CRA Git | Maintained and supported by SUSTech CRA and CCSE