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

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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: 2ad7bf3638 (“ipvlan: Initial check-in of the IPVLAN driver.”)
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mahesh Bandewar 2020-03-09 15:56:56 -07:00 committed by David S. Miller
parent 4b1bd9db07
commit ad8192767c
1 changed files with 10 additions and 8 deletions
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18
drivers/net/ipvlan/ipvlan_core.c
View File

@ -498,19 +498,21 @@ static int ipvlan_process_outbound(struct sk_buff *skb)
struct ethhdr *ethh = eth_hdr(skb); struct ethhdr *ethh = eth_hdr(skb);
int ret = NET_XMIT_DROP; int ret = NET_XMIT_DROP;
/* 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",
ntohs(skb->protocol));
kfree_skb(skb);
goto out;
}
/* The ipvlan is a pseudo-L2 device, so the packets that we receive /* The ipvlan is a pseudo-L2 device, so the packets that we receive
* will have L2; which need to discarded and processed further * will have L2; which need to discarded and processed further
* in the net-ns of the main-device. * in the net-ns of the main-device.
*/ */
if (skb_mac_header_was_set(skb)) { 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",
ntohs(skb->protocol));
kfree_skb(skb);
goto out;
}
skb_pull(skb, sizeof(*ethh)); skb_pull(skb, sizeof(*ethh));
skb->mac_header = (typeof(skb->mac_header))~0U; skb->mac_header = (typeof(skb->mac_header))~0U;
skb_reset_network_header(skb); skb_reset_network_header(skb);