| Message ID | 91961be2ab833139b1a4b0188ba47c2581b991d4.1548096161.git.lucien.xin@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] sctp: set flow sport from saddr only when it's 0 | expand |
From: Xin Long <lucien.xin@gmail.com> Date: Tue, 22 Jan 2019 02:42:41 +0800 > Now sctp_transport_pmtu() passes transport->saddr into .get_dst() to set > flow sport from 'saddr'. However, transport->saddr is set only when > transport->dst exists in sctp_transport_route(). > > If sctp_transport_pmtu() is called without transport->saddr set, like > when transport->dst doesn't exists, the flow sport will be set to 0 > from transport->saddr, which will cause a wrong route to be got. > > Commit 6e91b578bf3f ("sctp: re-use sctp_transport_pmtu in > sctp_transport_route") made the issue be triggered more easily > since sctp_transport_pmtu() would be called in sctp_transport_route() > after that. > > In gerneral, fl4->fl4_sport should always be set to > htons(asoc->base.bind_addr.port), unless transport->asoc doesn't exist > in sctp_v4/6_get_dst(), which is the case: > > sctp_ootb_pkt_new() -> > sctp_transport_route() > > For that, we can simply handle it by setting flow sport from saddr only > when it's 0 in sctp_v4/6_get_dst(). > > Fixes: 6e91b578bf3f ("sctp: re-use sctp_transport_pmtu in sctp_transport_route") > Reported-by: Ying Xu <yinxu@redhat.com> > Signed-off-by: Xin Long <lucien.xin@gmail.com> Applied and queued up for -stable.
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index ed8e006..6200cd2 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -280,7 +280,8 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, if (saddr) { fl6->saddr = saddr->v6.sin6_addr; - fl6->fl6_sport = saddr->v6.sin6_port; + if (!fl6->fl6_sport) + fl6->fl6_sport = saddr->v6.sin6_port; pr_debug("src=%pI6 - ", &fl6->saddr); } diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index 4e0eeb1..6abc8b2 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -440,7 +440,8 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, } if (saddr) { fl4->saddr = saddr->v4.sin_addr.s_addr; - fl4->fl4_sport = saddr->v4.sin_port; + if (!fl4->fl4_sport) + fl4->fl4_sport = saddr->v4.sin_port; } pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
Now sctp_transport_pmtu() passes transport->saddr into .get_dst() to set flow sport from 'saddr'. However, transport->saddr is set only when transport->dst exists in sctp_transport_route(). If sctp_transport_pmtu() is called without transport->saddr set, like when transport->dst doesn't exists, the flow sport will be set to 0 from transport->saddr, which will cause a wrong route to be got. Commit 6e91b578bf3f ("sctp: re-use sctp_transport_pmtu in sctp_transport_route") made the issue be triggered more easily since sctp_transport_pmtu() would be called in sctp_transport_route() after that. In gerneral, fl4->fl4_sport should always be set to htons(asoc->base.bind_addr.port), unless transport->asoc doesn't exist in sctp_v4/6_get_dst(), which is the case: sctp_ootb_pkt_new() -> sctp_transport_route() For that, we can simply handle it by setting flow sport from saddr only when it's 0 in sctp_v4/6_get_dst(). Fixes: 6e91b578bf3f ("sctp: re-use sctp_transport_pmtu in sctp_transport_route") Reported-by: Ying Xu <yinxu@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> --- net/sctp/ipv6.c | 3 ++- net/sctp/protocol.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-)