On Thu, Sep 13, 2018 at 1:55 AM, Zang MingJie <zealot0...@gmail.com> wrote:
> On Thu, Sep 13, 2018 at 2:55 AM Darrell Ball <dlu...@gmail.com> wrote: > > > > Thanks for looking MingJie > > > > > > On Wed, Sep 12, 2018 at 2:16 AM, Zang MingJie <zealot0...@gmail.com> > wrote: > >> > >> When encounter an invalid packet, all changes made by the packet should > >> be reverted. Currently an invalid packet can change the seq number while > >> the connection is in SEQ_RECV state. > > > > > > > > Did you notice this check ? > > > > if (src->state < CT_DPIF_TCPS_SYN_SENT) { > > /* First packet from this end. Set its state */ > > Yes, this is exactly where we found the problem. If first reply packet > is invalid, it masses all following packets. > Based on your description in the commit message: " Currently an invalid packet can change the seq number while the connection is in SEQ_RECV state." we don't fall into this condition since SEQ_RECV > CT_DPIF_TCPS_SYN_SENT, right ? If you did not mean "SEQ_RECV", maybe you meant something else ? What the value of "src->state" where you saw an issue ? > > > > > > > > >> > >> > >> Signed-off-by: Zang MingJie <zealot0...@gmail.com> > >> --- > >> lib/conntrack-tcp.c | 10 ++++++++-- > >> 1 file changed, 8 insertions(+), 2 deletions(-) > >> > >> diff --git a/lib/conntrack-tcp.c b/lib/conntrack-tcp.c > >> index 86d313d28..7443a3293 100644 > >> --- a/lib/conntrack-tcp.c > >> +++ b/lib/conntrack-tcp.c > >> @@ -151,9 +151,9 @@ tcp_conn_update(struct conn *conn_, struct > conntrack_bucket *ctb, > >> struct conn_tcp *conn = conn_tcp_cast(conn_); > >> struct tcp_header *tcp = dp_packet_l4(pkt); > >> /* The peer that sent 'pkt' */ > >> - struct tcp_peer *src = &conn->peer[reply ? 1 : 0]; > >> + struct tcp_peer orig_src, *src = &conn->peer[reply ? 1 : 0]; > >> /* The peer that should receive 'pkt' */ > >> - struct tcp_peer *dst = &conn->peer[reply ? 0 : 1]; > >> + struct tcp_peer orig_dst, *dst = &conn->peer[reply ? 0 : 1]; > >> uint8_t sws = 0, dws = 0; > >> uint16_t tcp_flags = TCP_FLAGS(tcp->tcp_ctl); > >> > >> @@ -187,6 +187,10 @@ tcp_conn_update(struct conn *conn_, struct > conntrack_bucket *ctb, > >> dws = TCP_MAX_WSCALE; > >> } > >> > >> + > >> + orig_src = *src; > >> + orig_dst = *dst; > >> + > >> /* > >> * Sequence tracking algorithm from Guido van Rooij's paper: > >> * http://www.madison-gurkha.com/publications/tcp_filtering/ > >> @@ -385,6 +389,8 @@ tcp_conn_update(struct conn *conn_, struct > conntrack_bucket *ctb, > >> src->state = dst->state = CT_DPIF_TCPS_TIME_WAIT; > >> } > >> } else { > >> + *src = orig_src; > >> + *dst = orig_dst; > >> return CT_UPDATE_INVALID; > >> } > >> > >> -- > >> 2.19.0.rc1 > >> > >> _______________________________________________ > >> dev mailing list > >> d...@openvswitch.org > >> https://mail.openvswitch.org/mailman/listinfo/ovs-dev > > > > > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev