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authorMahesh Bandewar <maheshb@google.com>2020-03-09 15:56:56 -0700
committerDavid S. Miller <davem@davemloft.net>2020-03-09 17:59:25 -0700
commitad8192767c9f9cf97da57b9ffcea70fb100febef (patch)
tree709ab896144397055fbbf3c5631548305b04a161 /drivers/net/ipvlan
parent4b1bd9db078f7d5332c8601a2f5bd43cf0458fd4 (diff)
downloadlinux-next-ad8192767c9f9cf97da57b9ffcea70fb100febef.tar.gz
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: 2ad7bf363841 (“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>
Diffstat (limited to 'drivers/net/ipvlan')
-rw-r--r--drivers/net/ipvlan/ipvlan_core.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 30cd0c4f0be0..53dac397db37 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -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 */
- 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
* 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",
+ ntohs(skb->protocol));
+ kfree_skb(skb);
+ goto out;
+ }
+
skb_pull(skb, sizeof(*ethh));
skb->mac_header = (typeof(skb->mac_header))~0U;
skb_reset_network_header(skb);