From 93efac3f2e03321129de67a3c0ba53048bb53e31 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Fri, 4 Sep 2015 13:21:06 +0800 Subject: [PATCH] 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 Signed-off-by: Steffen Klassert --- net/ipv6/xfrm6_output.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c index 09c76a7b474d..be033f22a3f3 100644 --- a/net/ipv6/xfrm6_output.c +++ b/net/ipv6/xfrm6_output.c @@ -136,6 +136,7 @@ static int __xfrm6_output(struct sock *sk, struct sk_buff *skb) 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 @@ static int __xfrm6_output(struct sock *sk, struct sk_buff *skb) } #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); } -- 2.39.5