Messages in this thread Patch in this message | | | From | Xin Long <> | Subject | [PATCH net] sctp: set flow sport from saddr only when it's 0 | 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> --- net/sctp/ipv6.c | 3 ++- net/sctp/protocol.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-)
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, -- 2.1.0
| |