The branch main has been updated by rscheff: URL: https://cgit.FreeBSD.org/src/commit/?id=b352ef58c29b1f2967e358c147e0f7faf8cfbef3
commit b352ef58c29b1f2967e358c147e0f7faf8cfbef3 Author: Richard Scheffenegger <[email protected]> AuthorDate: 2023-07-26 22:41:25 +0000 Commit: Richard Scheffenegger <[email protected]> CommitDate: 2023-07-26 22:42:26 +0000 tcp: Handle <RST,ACK> in SYN-RCVD Patch base stack to correctly handle the RST bit independently of other header flags per TCP RFC. MFC after: 1 week Reviewed By: tuexen, #transport Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D40982 --- sys/netinet/tcp_input.c | 4 ++++ sys/netinet/tcp_syncache.c | 12 ------------ 2 files changed, 4 insertions(+), 12 deletions(-) diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index 10daab2d61ba..b66e4e9d17ac 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -1963,6 +1963,10 @@ tcp_do_segment(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th, * if seg contains an ACK, but not for our SYN/ACK, send a RST. */ case TCPS_SYN_RECEIVED: + if (thflags & TH_RST) { + /* Handle RST segments later. */ + break; + } if ((thflags & TH_ACK) && (SEQ_LEQ(th->th_ack, tp->snd_una) || SEQ_GT(th->th_ack, tp->snd_max))) { diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c index b9c41eda4d9e..986d4d068f96 100644 --- a/sys/netinet/tcp_syncache.c +++ b/sys/netinet/tcp_syncache.c @@ -623,18 +623,6 @@ syncache_chkrst(struct in_conninfo *inc, struct tcphdr *th, struct mbuf *m, sc = syncache_lookup(inc, &sch); /* returns locked sch */ SCH_LOCK_ASSERT(sch); - /* - * Any RST to our SYN|ACK must not carry ACK, SYN or FIN flags. - * See RFC 793 page 65, section SEGMENT ARRIVES. - */ - if (tcp_get_flags(th) & (TH_ACK|TH_SYN|TH_FIN)) { - if ((s = tcp_log_addrs(inc, th, NULL, NULL))) - log(LOG_DEBUG, "%s; %s: Spurious RST with ACK, SYN or " - "FIN flag set, segment ignored\n", s, __func__); - TCPSTAT_INC(tcps_badrst); - goto done; - } - /* * No corresponding connection was found in syncache. * If syncookies are enabled and possibly exclusively
