Fix from r226623 is not sufficient to close all races in pfsync(4).
The root of problem is re-locking at the end of pfsync_sendout(). Several functions are calling pfsync_sendout() holding pointers to pf data on stack, and these functions expect this data to be consistent. To fix this, the following approach was taken: - The pfsync_sendout() doesn't call ip_output() directly, but enqueues the mbuf on sc->sc_ifp's interfaces queue, that is currently unused. Then pfsync netisr is scheduled. PF_LOCK isn't dropped in pfsync_sendout(). - The netisr runs through queue and ip_output()s packets on it. Apart from fixing race, this also decouples stack, fixing potential issues, that may happen, when sending pfsync(4) packets on input path. Reviewed by: eri (a quick review)
This commit is contained in:
Gleb Smirnoff
parent
72be4c6f03
commit
35ad95774e
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=226660
@ -856,7 +856,11 @@ pfsync_state_import(struct pfsync_state *sp, u_int8_t flags)
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CLR(st->state_flags, PFSTATE_NOSYNC);
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if (ISSET(st->state_flags, PFSTATE_ACK)) {
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pfsync_q_ins(st, PFSYNC_S_IACK);
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#ifdef __FreeBSD__
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pfsync_sendout();
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#else
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schednetisr(NETISR_PFSYNC);
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#endif
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}
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}
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CLR(st->state_flags, PFSTATE_ACK);
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@ -1312,7 +1316,11 @@ pfsync_in_upd(struct pfsync_pkt *pkt, struct mbuf *m, int offset, int count)
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V_pfsyncstats.pfsyncs_stale++;
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pfsync_update_state(st);
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#ifdef __FreeBSD__
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pfsync_sendout();
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#else
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schednetisr(NETISR_PFSYNC);
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#endif
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continue;
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}
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pfsync_alloc_scrub_memory(&sp->dst, &st->dst);
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@ -1418,7 +1426,11 @@ pfsync_in_upd_c(struct pfsync_pkt *pkt, struct mbuf *m, int offset, int count)
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V_pfsyncstats.pfsyncs_stale++;
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pfsync_update_state(st);
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#ifdef __FreeBSD__
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pfsync_sendout();
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#else
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schednetisr(NETISR_PFSYNC);
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#endif
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continue;
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}
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pfsync_alloc_scrub_memory(&up->dst, &st->dst);
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@ -2146,6 +2158,7 @@ pfsync_sendout(void)
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#endif
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#ifdef __FreeBSD__
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size_t pktlen;
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int dummy_error;
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#endif
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int offset;
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int q, count = 0;
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@ -2349,32 +2362,21 @@ pfsync_sendout(void)
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#ifdef __FreeBSD__
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sc->sc_ifp->if_opackets++;
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sc->sc_ifp->if_obytes += m->m_pkthdr.len;
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sc->sc_len = PFSYNC_MINPKT;
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IFQ_ENQUEUE(&sc->sc_ifp->if_snd, m, dummy_error);
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schednetisr(NETISR_PFSYNC);
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#else
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sc->sc_if.if_opackets++;
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sc->sc_if.if_obytes += m->m_pkthdr.len;
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#endif
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sc->sc_len = PFSYNC_MINPKT;
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#ifdef __FreeBSD__
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PF_UNLOCK();
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#endif
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if (ip_output(m, NULL, NULL, IP_RAWOUTPUT, &sc->sc_imo, NULL) == 0)
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#ifdef __FreeBSD__
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{
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PF_LOCK();
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#endif
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V_pfsyncstats.pfsyncs_opackets++;
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#ifdef __FreeBSD__
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}
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#endif
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pfsyncstats.pfsyncs_opackets++;
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else
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#ifdef __FreeBSD__
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{
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PF_LOCK();
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#endif
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V_pfsyncstats.pfsyncs_oerrors++;
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#ifdef __FreeBSD__
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}
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pfsyncstats.pfsyncs_oerrors++;
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/* start again */
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sc->sc_len = PFSYNC_MINPKT;
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#endif
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}
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@ -2422,7 +2424,11 @@ pfsync_insert_state(struct pf_state *st)
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pfsync_q_ins(st, PFSYNC_S_INS);
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if (ISSET(st->state_flags, PFSTATE_ACK))
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#ifdef __FreeBSD__
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pfsync_sendout();
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#else
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schednetisr(NETISR_PFSYNC);
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#endif
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else
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st->sync_updates = 0;
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}
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@ -2619,7 +2625,11 @@ pfsync_update_state(struct pf_state *st)
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if (sync || (time_second - st->pfsync_time) < 2) {
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pfsync_upds++;
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#ifdef __FreeBSD__
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pfsync_sendout();
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#else
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schednetisr(NETISR_PFSYNC);
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#endif
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}
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}
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@ -2670,7 +2680,11 @@ pfsync_request_update(u_int32_t creatorid, u_int64_t id)
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TAILQ_INSERT_TAIL(&sc->sc_upd_req_list, item, ur_entry);
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sc->sc_len += nlen;
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#ifdef __FreeBSD__
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pfsync_sendout();
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#else
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schednetisr(NETISR_PFSYNC);
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#endif
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}
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void
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@ -2699,7 +2713,11 @@ pfsync_update_state_req(struct pf_state *st)
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pfsync_q_del(st);
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case PFSYNC_S_NONE:
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pfsync_q_ins(st, PFSYNC_S_UPD);
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#ifdef __FreeBSD__
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pfsync_sendout();
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#else
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schednetisr(NETISR_PFSYNC);
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#endif
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return;
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case PFSYNC_S_INS:
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@ -3253,37 +3271,38 @@ pfsync_timeout(void *arg)
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void
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#ifdef __FreeBSD__
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pfsyncintr(void *arg)
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#else
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pfsyncintr(void)
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#endif
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{
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#ifdef __FreeBSD__
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struct pfsync_softc *sc = arg;
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#endif
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int s;
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#ifdef __FreeBSD__
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if (sc == NULL)
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return;
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struct mbuf *m;
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CURVNET_SET(sc->sc_ifp->if_vnet);
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#endif
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pfsync_ints++;
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for (;;) {
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IF_DEQUEUE(&sc->sc_ifp->if_snd, m);
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if (m == 0)
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break;
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if (ip_output(m, NULL, NULL, IP_RAWOUTPUT, &sc->sc_imo, NULL)
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== 0)
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V_pfsyncstats.pfsyncs_opackets++;
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else
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V_pfsyncstats.pfsyncs_oerrors++;
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}
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CURVNET_RESTORE();
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}
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#else
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pfsyncintr(void)
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{
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int s;
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pfsync_ints++;
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s = splnet();
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#ifdef __FreeBSD__
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PF_LOCK();
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#endif
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pfsync_sendout();
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#ifdef __FreeBSD__
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PF_UNLOCK();
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#endif
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splx(s);
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#ifdef __FreeBSD__
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CURVNET_RESTORE();
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#endif
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}
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#endif
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int
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pfsync_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
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