From d7ab5cdce54da631f0c8c11e506c974536a3581e Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 20 Sep 2018 17:27:28 +0800 Subject: [PATCH] sctp: update dst pmtu with the correct daddr When processing pmtu update from an icmp packet, it calls .update_pmtu with sk instead of skb in sctp_transport_update_pmtu. However for sctp, the daddr in the transport might be different from inet_sock->inet_daddr or sk->sk_v6_daddr, which is used to update or create the route cache. The incorrect daddr will cause a different route cache created for the path. So before calling .update_pmtu, inet_sock->inet_daddr/sk->sk_v6_daddr should be updated with the daddr in the transport, and update it back after it's done. The issue has existed since route exceptions introduction. Fixes: 4895c771c7f0 ("ipv4: Add FIB nexthop exceptions.") Reported-by: ian.periam@dialogic.com Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- net/sctp/transport.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/sctp/transport.c b/net/sctp/transport.c index 12cac85da994..033696e6f74f 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -260,6 +260,7 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk) bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu) { struct dst_entry *dst = sctp_transport_dst_check(t); + struct sock *sk = t->asoc->base.sk; bool change = true; if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { @@ -271,12 +272,19 @@ bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu) pmtu = SCTP_TRUNC4(pmtu); if (dst) { - dst->ops->update_pmtu(dst, t->asoc->base.sk, NULL, pmtu); + struct sctp_pf *pf = sctp_get_pf_specific(dst->ops->family); + union sctp_addr addr; + + pf->af->from_sk(&addr, sk); + pf->to_sk_daddr(&t->ipaddr, sk); + dst->ops->update_pmtu(dst, sk, NULL, pmtu); + pf->to_sk_daddr(&addr, sk); + dst = sctp_transport_dst_check(t); } if (!dst) { - t->af_specific->get_dst(t, &t->saddr, &t->fl, t->asoc->base.sk); + t->af_specific->get_dst(t, &t->saddr, &t->fl, sk); dst = t->dst; }