From owner-dev-commits-src-main@freebsd.org Thu May 27 14:51:35 2021 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id C803963ED40; Thu, 27 May 2021 14:51:35 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4FrW3q5MFRz3nqv; Thu, 27 May 2021 14:51:35 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 959022628A; Thu, 27 May 2021 14:51:35 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 14REpZ6A015905; Thu, 27 May 2021 14:51:35 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 14REpZjN015904; Thu, 27 May 2021 14:51:35 GMT (envelope-from git) Date: Thu, 27 May 2021 14:51:35 GMT Message-Id: <202105271451.14REpZjN015904@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Randall Stewart Subject: git: 8c69d988a8d3 - main - tcp: When we have an out-of-order FIN we do want to strip off the FIN bit. MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: rrs X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 8c69d988a8d32e53310c7b73ec8721b04b7249e6 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 May 2021 14:51:35 -0000 The branch main has been updated by rrs: URL: https://cgit.FreeBSD.org/src/commit/?id=8c69d988a8d32e53310c7b73ec8721b04b7249e6 commit 8c69d988a8d32e53310c7b73ec8721b04b7249e6 Author: Randall Stewart AuthorDate: 2021-05-27 14:50:32 +0000 Commit: Randall Stewart CommitDate: 2021-05-27 14:50:32 +0000 tcp: When we have an out-of-order FIN we do want to strip off the FIN bit. The last set of commits fixed both a panic (in rack) and an ACK-war (in freebsd and bbr). However there was a missing case, i.e. where we get an out-of-order FIN by itself. In such a case we don't want to leave the FIN bit set, otherwise we will do the wrong thing and ack the FIN incorrectly. Instead we need to go through the tcp_reasm() code and that way the FIN will be stripped and all will be well. Reviewed by: mtuexen,rscheff Sponsored by: Netflix Inc Differential Revision: https://reviews.freebsd.org/D30497 --- sys/netinet/tcp_input.c | 7 ++++++- sys/netinet/tcp_stacks/bbr.c | 7 ++++++- sys/netinet/tcp_stacks/rack.c | 7 ++++++- 3 files changed, 18 insertions(+), 3 deletions(-) diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index b9836a137608..1dab2e511d95 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -3191,7 +3191,12 @@ dodata: /* XXX */ * when trimming from the head. */ tcp_seq temp = save_start; - if (tlen) { + if (tlen || (th->th_seq != tp->rcv_nxt)) { + /* + * We add the th_seq != rcv_nxt to + * catch the case of a stand alone out + * of order FIN. + */ thflags = tcp_reass(tp, th, &temp, &tlen, m); tp->t_flags |= TF_ACKNOW; } diff --git a/sys/netinet/tcp_stacks/bbr.c b/sys/netinet/tcp_stacks/bbr.c index b2fc5c1f928e..5b97c3d7800f 100644 --- a/sys/netinet/tcp_stacks/bbr.c +++ b/sys/netinet/tcp_stacks/bbr.c @@ -8320,7 +8320,12 @@ bbr_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so, * trimming from the head. */ tcp_seq temp = save_start; - if (tlen) { + if (tlen || (th->th_seq != tp->rcv_nxt)) { + /* + * We add the th_seq != rcv_nxt to + * catch the case of a stand alone out + * of order FIN. + */ thflags = tcp_reass(tp, th, &temp, &tlen, m); tp->t_flags |= TF_ACKNOW; } diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c index b7e8c1578f2b..1db09e30d968 100644 --- a/sys/netinet/tcp_stacks/rack.c +++ b/sys/netinet/tcp_stacks/rack.c @@ -10235,7 +10235,12 @@ rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so, * trimming from the head. */ tcp_seq temp = save_start; - if (tlen) { + if (tlen || (th->th_seq != tp->rcv_nxt)) { + /* + * We add the th_seq != rcv_nxt to + * catch the case of a stand alone out + * of order FIN. + */ thflags = tcp_reass(tp, th, &temp, &tlen, m); tp->t_flags |= TF_ACKNOW; }