xfrm: Verify MAC header exists before overwriting eth_hdr(skb)->h_proto

Artem Savkov reported that commit 5efec5c655 leads to a packet loss under
IPSec configuration. It appears that his setup consists of a TUN device,
which does not have a MAC header.

Make sure MAC header exists.

Note: TUN device sets a MAC header pointer, although it does not have one.

Fixes: 5efec5c655 ("xfrm: Fix eth_hdr(skb)->h_proto to reflect inner IP version")
Reported-by: Artem Savkov <artem.savkov@gmail.com>
Tested-by: Artem Savkov <artem.savkov@gmail.com>
Signed-off-by: Yossi Kuperman <yossiku@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Yossi Kuperman 2018-03-04 21:03:52 +02:00 committed by Steffen Klassert
parent b8b549eec8
commit 87cdf3148b
2 changed files with 4 additions and 2 deletions

View File

@ -92,7 +92,8 @@ static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
skb_reset_network_header(skb);
skb_mac_header_rebuild(skb);
eth_hdr(skb)->h_proto = skb->protocol;
if (skb->mac_len)
eth_hdr(skb)->h_proto = skb->protocol;
err = 0;

View File

@ -92,7 +92,8 @@ static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
skb_reset_network_header(skb);
skb_mac_header_rebuild(skb);
eth_hdr(skb)->h_proto = skb->protocol;
if (skb->mac_len)
eth_hdr(skb)->h_proto = skb->protocol;
err = 0;