ipv6: Fix IPsec pre-encap fragmentation check
The IPv6 IPsec pre-encap path performs fragmentation for tunnel-mode
packets. That is, we perform fragmentation pre-encap rather than
post-encap.
A check was added later to ensure that proper MTU information is
passed back for locally generated traffic. Unfortunately this
check was performed on all IPsec packets, including transport-mode
packets.
What's more, the check failed to take GSO into account.
The end result is that transport-mode GSO packets get dropped at
the check.
This patch fixes it by moving the tunnel mode check forward as well
as adding the GSO check.
Fixes: dd767856a36e ("xfrm6: Don't call icmpv6_send on local error")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 09c76a7..be033f2 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -136,6 +136,7 @@
struct dst_entry *dst = skb_dst(skb);
struct xfrm_state *x = dst->xfrm;
int mtu;
+ bool toobig;
#ifdef CONFIG_NETFILTER
if (!x) {
@@ -144,25 +145,29 @@
}
#endif
+ if (x->props.mode != XFRM_MODE_TUNNEL)
+ goto skip_frag;
+
if (skb->protocol == htons(ETH_P_IPV6))
mtu = ip6_skb_dst_mtu(skb);
else
mtu = dst_mtu(skb_dst(skb));
- if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
+ toobig = skb->len > mtu && !skb_is_gso(skb);
+
+ if (toobig && xfrm6_local_dontfrag(skb)) {
xfrm6_local_rxpmtu(skb, mtu);
return -EMSGSIZE;
- } else if (!skb->ignore_df && skb->len > mtu && skb->sk) {
+ } else if (!skb->ignore_df && toobig && skb->sk) {
xfrm_local_error(skb, mtu);
return -EMSGSIZE;
}
- if (x->props.mode == XFRM_MODE_TUNNEL &&
- ((skb->len > mtu && !skb_is_gso(skb)) ||
- dst_allfrag(skb_dst(skb)))) {
+ if (toobig || dst_allfrag(skb_dst(skb)))
return ip6_fragment(sk, skb,
x->outer_mode->afinfo->output_finish);
- }
+
+skip_frag:
return x->outer_mode->afinfo->output_finish(sk, skb);
}