Date: Tue, 4 Dec 2018 22:14:18 +0000 (UTC) From: Michael Tuexen <tuexen@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r341501 - stable/12/sys/netinet/tcp_stacks Message-ID: <201812042214.wB4MEIIl098548@repo.freebsd.org>
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Author: tuexen Date: Tue Dec 4 22:14:18 2018 New Revision: 341501 URL: https://svnweb.freebsd.org/changeset/base/341501 Log: MFC r340782: 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@ Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D18034 Modified: stable/12/sys/netinet/tcp_stacks/rack.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/netinet/tcp_stacks/rack.c ============================================================================== --- stable/12/sys/netinet/tcp_stacks/rack.c Tue Dec 4 22:13:05 2018 (r341500) +++ stable/12/sys/netinet/tcp_stacks/rack.c Tue Dec 4 22:14:18 2018 (r341501) @@ -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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