ipsec: be careful of non existing mac headers

Niccolo Belli reported ipsec crashes in case we handle a frame without
mac header (atm in his case)

Before copying mac header, better make sure it is present.

Bugzilla reference:  https://bugzilla.kernel.org/show_bug.cgi?id=42809

Reported-by: Niccolò Belli <darkbasic@linuxsystems.it>
Tested-by: Niccolò Belli <darkbasic@linuxsystems.it>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2012-02-23 10:55:02 +00:00
committed by David S. Miller
parent 4a2258dddd
commit 03606895cd
5 changed files with 16 additions and 17 deletions

View File

@@ -63,7 +63,6 @@ static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
{
int err = -EINVAL;
const unsigned char *old_mac;
if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
goto out;
@@ -80,10 +79,9 @@ static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
if (!(x->props.flags & XFRM_STATE_NOECN))
ipip6_ecn_decapsulate(skb);
old_mac = skb_mac_header(skb);
skb_set_mac_header(skb, -skb->mac_len);
memmove(skb_mac_header(skb), old_mac, skb->mac_len);
skb_reset_network_header(skb);
skb_mac_header_rebuild(skb);
err = 0;
out: