Commit ca064bd8 authored Oct 19, 2015 by Steffen Klassert

xfrm: Fix pmtu discovery for local generated packets.



Commit 044a832a ("xfrm: Fix local error reporting crash
with interfamily tunnels") moved the setting of skb->protocol
behind the last access of the inner mode family to fix an
interfamily crash. Unfortunately now skb->protocol might not
be set at all, so we fail dispatch to the inner address family.
As a reault, the local error handler is not called and the
mtu value is not reported back to userspace.

We fix this by setting skb->protocol on message size errors
before we call xfrm_local_error.

Fixes: 044a832a ("xfrm: Fix local error reporting crash with interfamily tunnels")
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

parent 4e077237

net/ipv4/xfrm4_output.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -30,6 +30,8 @@ static int xfrm4_tunnel_check_size(struct sk_buff *skb)

		mtu = dst_mtu(skb_dst(skb));
		if (skb->len > mtu) {
		skb->protocol = htons(ETH_P_IP);

		if (skb->sk)
		xfrm_local_error(skb, mtu);
		else

net/ipv6/xfrm6_output.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -79,6 +79,7 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb)

		if (!skb->ignore_df && skb->len > mtu) {
		skb->dev = dst->dev;
		skb->protocol = htons(ETH_P_IPV6);

		if (xfrm6_local_dontfrag(skb))
		xfrm6_local_rxpmtu(skb, mtu);