> On 13. Jan 2021, at 16:33, Kyle Evans <kev...@freebsd.org> wrote: > > On Wed, Jan 13, 2021 at 9:31 AM Michael Tuexen <tue...@freebsd.org> wrote: >> >>> On 13. Jan 2021, at 16:16, Kyle Evans <kev...@freebsd.org> wrote: >>> >>> On Wed, Jan 6, 2021 at 9:01 AM Kyle Evans <kev...@freebsd.org> wrote: >>>> >>>> On Mon, Nov 30, 2020 at 3:45 AM Michael Tuexen <tue...@freebsd.org> wrote: >>>>> >>>>> Author: tuexen >>>>> Date: Mon Nov 30 09:45:44 2020 >>>>> New Revision: 368181 >>>>> URL: https://svnweb.freebsd.org/changeset/base/368181 >>>>> >>>>> Log: >>>>> MFC r367530: >>>>> RFC 7323 specifies that: >>>>> * TCP segments without timestamps should be dropped when support for >>>>> the timestamp option has been negotiated. >>>>> * TCP segments with timestamps should be processed normally if support >>>>> for the timestamp option has not been negotiated. >>>>> This patch enforces the above. >>>>> Manually resolved merge conflicts. >>>>> >>>>> MFC 367891: >>>>> Fix an issue I introuced in r367530: tcp_twcheck() can be called >>>>> with to == NULL for SYN segments. So don't assume tp != NULL. >>>>> Thanks to jhb@ for reporting and suggesting a fix. >>>>> >>>>> MFC r367946: >>>>> Fix two occurences of a typo in a comment introduced in r367530. >>>>> Thanks to lstewart@ for reporting them. >>>>> >>>> >>>> Hi Michael, >>>> >>>> Dmitri (CC'd) spotted a regression in the golang test suite along >>>> stable/12 and bisected it back to this MFC (reported via >>>> efnet#bsdports). The test puts up a local HTTP server and attempts to >>>> close the read-side while the write-side is still going, hopefully >>>> observing a write failure on the write-side in the process (but it >>>> never does). >>>> >>>> I minimized it to this (rough) reproducer, which shows the write side >>>> hanging around in CLOSE_WAIT and successfully writing the msg >>>> repeatedly on recent -CURRENT while 12.2 observes an EPIPE almost >>>> immediately: https://people.freebsd.org/~kevans/tcpr.c >>>> >>>> root@viper:~/grep# sockstat -s | grep 8993 >>>> root a.out 80831 4 tcp4 127.0.0.1:8993 *:* >>>> LISTEN >>>> root a.out 80831 5 tcp4 127.0.0.1:8993 >>>> 127.0.0.1:40319 CLOSE_WAIT >>>> root@viper:~/grep# >>>> >>> >>> Ping? >> Hi Kyle, >> >> thanks for pinging. I missed your original mail (not sure why it did not end >> up in the >> correct mailbox). Will look into it later today/tomorrow. >> >> Thanks for providing a reproducer. Just to get it crystal clear: You say >> that the >> programs runs fine on CURRENT but not on stable/12. Is that correct? >> > > Excellent, thanks! It runs fine on 12.2, but not on an up-to-date > -CURRENT or stable/12 after this MFC. The issue should be fixed by https://reviews.freebsd.org/D28143
With that patch your reproducer terminates immediately, sometimes reporting tuexen@head:~ % ./tcpr waiting for server attempting to connect got client connected, closing waiting write fail (bad!): 54 and sometimes reporting tuexen@head:~ % ./tcpr waiting for server attempting to connect connected, closing waiting got client pipe gone (good!) but that depends on the timing. Thanks for reporting the issue! Best regards Michael >> Best regards >> Michael >>> >>>>> >>>>> Modified: >>>>> stable/12/sys/netinet/tcp_input.c >>>>> stable/12/sys/netinet/tcp_stacks/rack.c >>>>> stable/12/sys/netinet/tcp_syncache.c >>>>> stable/12/sys/netinet/tcp_timewait.c >>>>> Directory Properties: >>>>> stable/12/ (props changed) >>>>> >>>>> Modified: stable/12/sys/netinet/tcp_input.c >>>>> ============================================================================== >>>>> --- stable/12/sys/netinet/tcp_input.c Mon Nov 30 09:22:33 2020 >>>>> (r368180) >>>>> +++ stable/12/sys/netinet/tcp_input.c Mon Nov 30 09:45:44 2020 >>>>> (r368181) >>>>> @@ -975,8 +975,8 @@ findpcb: >>>>> } >>>>> INP_INFO_RLOCK_ASSERT(&V_tcbinfo); >>>>> >>>>> - if (thflags & TH_SYN) >>>>> - tcp_dooptions(&to, optp, optlen, TO_SYN); >>>>> + tcp_dooptions(&to, optp, optlen, >>>>> + (thflags & TH_SYN) ? TO_SYN : 0); >>>>> /* >>>>> * NB: tcp_twcheck unlocks the INP and frees the mbuf. >>>>> */ >>>>> @@ -1706,20 +1706,29 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, >>>>> stru >>>>> } >>>>> >>>>> /* >>>>> - * If timestamps were negotiated during SYN/ACK they should >>>>> - * appear on every segment during this session and vice versa. >>>>> + * If timestamps were negotiated during SYN/ACK and a >>>>> + * segment without a timestamp is received, silently drop >>>>> + * the segment. >>>>> + * See section 3.2 of RFC 7323. >>>>> */ >>>>> if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS)) { >>>>> if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { >>>>> log(LOG_DEBUG, "%s; %s: Timestamp missing, " >>>>> - "no action\n", s, __func__); >>>>> + "segment silently dropped\n", s, __func__); >>>>> free(s, M_TCPLOG); >>>>> } >>>>> + goto drop; >>>>> } >>>>> + /* >>>>> + * If timestamps were not negotiated during SYN/ACK and a >>>>> + * segment with a timestamp is received, ignore the >>>>> + * timestamp and process the packet normally. >>>>> + * See section 3.2 of RFC 7323. >>>>> + */ >>>>> if (!(tp->t_flags & TF_RCVD_TSTMP) && (to.to_flags & TOF_TS)) { >>>>> if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { >>>>> log(LOG_DEBUG, "%s; %s: Timestamp not expected, " >>>>> - "no action\n", s, __func__); >>>>> + "segment processed normally\n", s, __func__); >>>>> free(s, M_TCPLOG); >>>>> } >>>>> } >>>>> >>>>> Modified: stable/12/sys/netinet/tcp_stacks/rack.c >>>>> ============================================================================== >>>>> --- stable/12/sys/netinet/tcp_stacks/rack.c Mon Nov 30 09:22:33 2020 >>>>> (r368180) >>>>> +++ stable/12/sys/netinet/tcp_stacks/rack.c Mon Nov 30 09:45:44 2020 >>>>> (r368181) >>>>> @@ -6708,7 +6708,27 @@ rack_hpts_do_segment(struct mbuf *m, struct tcphdr >>>>> *th >>>>> TCP_LOG_EVENT(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_IN, >>>>> 0, >>>>> tlen, &log, true); >>>>> } >>>>> + >>>>> /* >>>>> + * Parse options on any incoming segment. >>>>> + */ >>>>> + tcp_dooptions(&to, (u_char *)(th + 1), >>>>> + (th->th_off << 2) - sizeof(struct tcphdr), >>>>> + (thflags & TH_SYN) ? TO_SYN : 0); >>>>> + >>>>> + /* >>>>> + * If timestamps were negotiated during SYN/ACK and a >>>>> + * segment without a timestamp is received, silently drop >>>>> + * the segment. >>>>> + * See section 3.2 of RFC 7323. >>>>> + */ >>>>> + if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS)) { >>>>> + way_out = 5; >>>>> + retval = 0; >>>>> + goto done_with_input; >>>>> + } >>>>> + >>>>> + /* >>>>> * Segment received on connection. Reset idle time and keep-alive >>>>> * timer. XXX: This should be done after segment validation to >>>>> * ignore broken/spoofed segs. >>>>> @@ -6761,12 +6781,6 @@ rack_hpts_do_segment(struct mbuf *m, struct tcphdr >>>>> *th >>>>> rack_cong_signal(tp, th, CC_ECN); >>>>> } >>>>> } >>>>> - /* >>>>> - * Parse options on any incoming segment. >>>>> - */ >>>>> - tcp_dooptions(&to, (u_char *)(th + 1), >>>>> - (th->th_off << 2) - sizeof(struct tcphdr), >>>>> - (thflags & TH_SYN) ? TO_SYN : 0); >>>>> >>>>> /* >>>>> * If echoed timestamp is later than the current time, fall back to >>>>> @@ -6898,6 +6912,7 @@ rack_hpts_do_segment(struct mbuf *m, struct tcphdr >>>>> *th >>>>> rack_timer_audit(tp, rack, &so->so_snd); >>>>> way_out = 2; >>>>> } >>>>> + done_with_input: >>>>> rack_log_doseg_done(rack, cts, nxt_pkt, did_out, way_out); >>>>> if (did_out) >>>>> rack->r_wanted_output = 0; >>>>> >>>>> Modified: stable/12/sys/netinet/tcp_syncache.c >>>>> ============================================================================== >>>>> --- stable/12/sys/netinet/tcp_syncache.c Mon Nov 30 09:22:33 2020 >>>>> (r368180) >>>>> +++ stable/12/sys/netinet/tcp_syncache.c Mon Nov 30 09:45:44 2020 >>>>> (r368181) >>>>> @@ -1142,6 +1142,40 @@ syncache_expand(struct in_conninfo *inc, struct >>>>> tcpopt >>>>> } >>>>> >>>>> /* >>>>> + * If timestamps were not negotiated during SYN/ACK and a >>>>> + * segment with a timestamp is received, ignore the >>>>> + * timestamp and process the packet normally. >>>>> + * See section 3.2 of RFC 7323. >>>>> + */ >>>>> + if (!(sc->sc_flags & SCF_TIMESTAMP) && >>>>> + (to->to_flags & TOF_TS)) { >>>>> + if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { >>>>> + log(LOG_DEBUG, "%s; %s: Timestamp not " >>>>> + "expected, segment processed >>>>> normally\n", >>>>> + s, __func__); >>>>> + free(s, M_TCPLOG); >>>>> + s = NULL; >>>>> + } >>>>> + } >>>>> + >>>>> + /* >>>>> + * If timestamps were negotiated during SYN/ACK and a >>>>> + * segment without a timestamp is received, silently drop >>>>> + * the segment. >>>>> + * See section 3.2 of RFC 7323. >>>>> + */ >>>>> + if ((sc->sc_flags & SCF_TIMESTAMP) && >>>>> + !(to->to_flags & TOF_TS)) { >>>>> + SCH_UNLOCK(sch); >>>>> + if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { >>>>> + log(LOG_DEBUG, "%s; %s: Timestamp >>>>> missing, " >>>>> + "segment silently dropped\n", s, >>>>> __func__); >>>>> + free(s, M_TCPLOG); >>>>> + } >>>>> + return (-1); /* Do not send RST */ >>>>> + } >>>>> + >>>>> + /* >>>>> * Pull out the entry to unlock the bucket row. >>>>> * >>>>> * NOTE: We must decrease TCPS_SYN_RECEIVED count here, not >>>>> @@ -1184,32 +1218,6 @@ syncache_expand(struct in_conninfo *inc, struct >>>>> tcpopt >>>>> log(LOG_DEBUG, "%s; %s: SEQ %u != IRS+1 %u, segment >>>>> " >>>>> "rejected\n", s, __func__, th->th_seq, >>>>> sc->sc_irs); >>>>> goto failed; >>>>> - } >>>>> - >>>>> - /* >>>>> - * If timestamps were not negotiated during SYN/ACK they >>>>> - * must not appear on any segment during this session. >>>>> - */ >>>>> - if (!(sc->sc_flags & SCF_TIMESTAMP) && (to->to_flags & TOF_TS)) { >>>>> - if ((s = tcp_log_addrs(inc, th, NULL, NULL))) >>>>> - log(LOG_DEBUG, "%s; %s: Timestamp not expected, " >>>>> - "segment rejected\n", s, __func__); >>>>> - goto failed; >>>>> - } >>>>> - >>>>> - /* >>>>> - * If timestamps were negotiated during SYN/ACK they should >>>>> - * appear on every segment during this session. >>>>> - * XXXAO: This is only informal as there have been unverified >>>>> - * reports of non-compliants stacks. >>>>> - */ >>>>> - if ((sc->sc_flags & SCF_TIMESTAMP) && !(to->to_flags & TOF_TS)) { >>>>> - if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { >>>>> - log(LOG_DEBUG, "%s; %s: Timestamp missing, " >>>>> - "no action\n", s, __func__); >>>>> - free(s, M_TCPLOG); >>>>> - s = NULL; >>>>> - } >>>>> } >>>>> >>>>> *lsop = syncache_socket(sc, *lsop, m); >>>>> >>>>> Modified: stable/12/sys/netinet/tcp_timewait.c >>>>> ============================================================================== >>>>> --- stable/12/sys/netinet/tcp_timewait.c Mon Nov 30 09:22:33 2020 >>>>> (r368180) >>>>> +++ stable/12/sys/netinet/tcp_timewait.c Mon Nov 30 09:45:44 2020 >>>>> (r368181) >>>>> @@ -373,9 +373,10 @@ tcp_twstart(struct tcpcb *tp) >>>>> /* >>>>> * Returns 1 if the TIME_WAIT state was killed and we should start over, >>>>> * looking for a pcb in the listen state. Returns 0 otherwise. >>>>> + * It be called with to == NULL only for pure SYN-segments. >>>>> */ >>>>> int >>>>> -tcp_twcheck(struct inpcb *inp, struct tcpopt *to __unused, struct tcphdr >>>>> *th, >>>>> +tcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th, >>>>> struct mbuf *m, int tlen) >>>>> { >>>>> struct tcptw *tw; >>>>> @@ -396,6 +397,8 @@ tcp_twcheck(struct inpcb *inp, struct tcpopt *to __unu >>>>> goto drop; >>>>> >>>>> thflags = th->th_flags; >>>>> + KASSERT(to != NULL || (thflags & (TH_SYN | TH_ACK)) == TH_SYN, >>>>> + ("tcp_twcheck: called without options on a non-SYN >>>>> segment")); >>>>> >>>>> /* >>>>> * NOTE: for FIN_WAIT_2 (to be added later), >>>>> @@ -443,6 +446,16 @@ tcp_twcheck(struct inpcb *inp, struct tcpopt *to >>>>> __unu >>>>> */ >>>>> if ((thflags & TH_ACK) == 0) >>>>> goto drop; >>>>> + >>>>> + /* >>>>> + * If timestamps were negotiated during SYN/ACK and a >>>>> + * segment without a timestamp is received, silently drop >>>>> + * the segment. >>>>> + * See section 3.2 of RFC 7323. >>>>> + */ >>>>> + if (((to->to_flags & TOF_TS) == 0) && (tw->t_recent != 0)) { >>>>> + goto drop; >>>>> + } >>>>> >>>>> /* >>>>> * Reset the 2MSL timer if this is a duplicate FIN. >> _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"