Date: Thu, 22 Nov 2018 20:05:57 +0000 (UTC) From: Michael Tuexen <tuexen@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r340782 - head/sys/netinet/tcp_stacks Message-ID: <201811222005.wAMK5vGu089164@repo.freebsd.org>
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Author: tuexen Date: Thu Nov 22 20:05:57 2018 New Revision: 340782 URL: https://svnweb.freebsd.org/changeset/base/340782 Log: A TCP stack is required to check SEG.ACK first, when processing a segment in the SYN-SENT state as stated in Section 3.9 of RFC 793, page 66. Ensure this is also done by the TCP RACK stack. Reviewed by: rrs@ MFC after: 1 week Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D18034 Modified: head/sys/netinet/tcp_stacks/rack.c Modified: head/sys/netinet/tcp_stacks/rack.c ============================================================================== --- head/sys/netinet/tcp_stacks/rack.c Thu Nov 22 20:02:39 2018 (r340781) +++ head/sys/netinet/tcp_stacks/rack.c Thu Nov 22 20:05:57 2018 (r340782) @@ -6533,6 +6533,15 @@ rack_hpts_do_segment(struct mbuf *m, struct tcphdr *th goto done_with_input; } /* + * If a segment with the ACK-bit set arrives in the SYN-SENT state + * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9. + */ + if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) && + (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) { + rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); + return; + } + /* * Segment received on connection. Reset idle time and keep-alive * timer. XXX: This should be done after segment validation to * ignore broken/spoofed segs.
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