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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: dd767856a3 ("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>
This commit is contained in:
Herbert Xu 2015-09-04 13:21:06 +08:00 committed by Steffen Klassert
parent 724a7636ad
commit 93efac3f2e
1 changed files with 11 additions and 6 deletions
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17
net/ipv6/xfrm6_output.c
View File

@ -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);
}