Xin Long 37b34a91f3 sctp: set flow sport from saddr only when it's 0
[ Upstream commit ecf938fe7d0088077ee1280419a2b3c5429b47c8 ]

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-06 17:30:10 +01:00
..
2019-01-13 09:51:08 +01:00
2018-11-04 14:50:51 +01:00
2019-01-31 08:14:31 +01:00
2018-08-27 15:24:33 -07:00
2018-12-01 09:37:27 +01:00
2018-09-24 12:19:27 -07:00
2019-02-06 17:30:07 +01:00
2018-11-04 14:50:51 +01:00
2019-01-13 09:51:00 +01:00
2018-07-24 14:10:42 -07:00
2018-07-24 14:10:42 -07:00
2019-01-09 17:38:33 +01:00
2018-07-24 14:10:43 -07:00
2018-10-18 16:43:06 -07:00