Date: Tue, 21 Jul 2015 23:42:18 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r285778 - stable/10/sys/netinet Message-ID: <201507212342.t6LNgIO6019235@repo.freebsd.org>
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Author: delphij Date: Tue Jul 21 23:42:17 2015 New Revision: 285778 URL: https://svnweb.freebsd.org/changeset/base/285778 Log: Fix resource exhaustion due to sessions stuck in LAST_ACK state. Security: CVE-2015-5358 Security: SA-15:13.tcp Submitted by: Jonathan Looney (Juniper SIRT) Approved by: re (so blanket) Modified: stable/10/sys/netinet/tcp_output.c Modified: stable/10/sys/netinet/tcp_output.c ============================================================================== --- stable/10/sys/netinet/tcp_output.c Tue Jul 21 23:42:15 2015 (r285777) +++ stable/10/sys/netinet/tcp_output.c Tue Jul 21 23:42:17 2015 (r285778) @@ -400,7 +400,7 @@ after_sack_rexmit: flags &= ~TH_FIN; } - if (len < 0) { + if (len <= 0) { /* * If FIN has been sent but not acked, * but we haven't been called to retransmit, @@ -410,9 +410,16 @@ after_sack_rexmit: * to (closed) window, and set the persist timer * if it isn't already going. If the window didn't * close completely, just wait for an ACK. + * + * We also do a general check here to ensure that + * we will set the persist timer when we have data + * to send, but a 0-byte window. This makes sure + * the persist timer is set even if the packet + * hits one of the "goto send" lines below. */ len = 0; - if (sendwin == 0) { + if ((sendwin == 0) && (TCPS_HAVEESTABLISHED(tp->t_state)) && + (off < (int) so->so_snd.sb_cc)) { tcp_timer_activate(tp, TT_REXMT, 0); tp->t_rxtshift = 0; tp->snd_nxt = tp->snd_una;
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