Date: Tue, 14 May 2019 21:30:55 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r347582 - in head/sys: netinet netinet6 Message-ID: <201905142130.x4ELUtr2002700@repo.freebsd.org>
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Author: markj Date: Tue May 14 21:30:55 2019 New Revision: 347582 URL: https://svnweb.freebsd.org/changeset/base/347582 Log: Close some races in multicast socket option handling. r333175 converted the global multicast lock to a sleepable sx lock, so the lock order with respect to the (non-sleepable) inp lock changed. To handle this, r333175 and r333505 added code to drop the inp lock, but this opened races that could leave multicast group description structures in an inconsistent state. This change fixes the problem by simply acquiring the global lock sooner. Along the way, this fixes some LORs and bogus error handling introduced in r333175, and commits some related cleanup. Reported by: syzbot+ba7c4943547e0604faca@syzkaller.appspotmail.com Reported by: syzbot+1b803796ab94d11a46f9@syzkaller.appspotmail.com Reviewed by: ae MFC after: 3 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D20070 Modified: head/sys/netinet/in_mcast.c head/sys/netinet6/in6_mcast.c Modified: head/sys/netinet/in_mcast.c ============================================================================== --- head/sys/netinet/in_mcast.c Tue May 14 21:11:15 2019 (r347581) +++ head/sys/netinet/in_mcast.c Tue May 14 21:30:55 2019 (r347582) @@ -1534,6 +1534,7 @@ inp_block_unblock_source(struct inpcb *inp, struct soc /* * Check if we are actually a member of this group. */ + IN_MULTI_LOCK(); imo = inp_findmoptions(inp); idx = imo_match_group(imo, ifp, &gsa->sa); if (idx == -1 || imo->imo_mfilters == NULL) { @@ -1593,14 +1594,13 @@ inp_block_unblock_source(struct inpcb *inp, struct soc /* * Begin state merge transaction at IGMP layer. */ - IN_MULTI_LOCK(); CTR1(KTR_IGMPV3, "%s: merge inm state", __func__); IN_MULTI_LIST_LOCK(); error = inm_merge(inm, imf); if (error) { CTR1(KTR_IGMPV3, "%s: failed to merge inm state", __func__); IN_MULTI_LIST_UNLOCK(); - goto out_in_multi_locked; + goto out_imf_rollback; } CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__); @@ -1609,9 +1609,6 @@ inp_block_unblock_source(struct inpcb *inp, struct soc if (error) CTR1(KTR_IGMPV3, "%s: failed igmp downcall", __func__); -out_in_multi_locked: - - IN_MULTI_UNLOCK(); out_imf_rollback: if (error) imf_rollback(imf); @@ -1622,6 +1619,7 @@ out_imf_rollback: out_inp_locked: INP_WUNLOCK(inp); + IN_MULTI_UNLOCK(); return (error); } @@ -1680,10 +1678,10 @@ inp_findmoptions(struct inpcb *inp) static void inp_gcmoptions(struct ip_moptions *imo) { - struct in_mfilter *imf; + struct in_mfilter *imf; struct in_multi *inm; struct ifnet *ifp; - size_t idx, nmships; + size_t idx, nmships; nmships = imo->imo_num_memberships; for (idx = 0; idx < nmships; ++idx) { @@ -2142,12 +2140,12 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt CTR2(KTR_IGMPV3, "%s: unknown sopt_name %d", __func__, sopt->sopt_name); return (EOPNOTSUPP); - break; } if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) return (EADDRNOTAVAIL); + IN_MULTI_LOCK(); imo = inp_findmoptions(inp); idx = imo_match_group(imo, ifp, &gsa->sa); if (idx == -1) { @@ -2272,10 +2270,6 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt /* * Begin state merge transaction at IGMP layer. */ - in_pcbref(inp); - INP_WUNLOCK(inp); - IN_MULTI_LOCK(); - if (is_new) { error = in_joingroup_locked(ifp, &gsa->sin.sin_addr, imf, &inm); @@ -2286,6 +2280,8 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt goto out_imo_free; } inm_acquire(inm); + KASSERT(imo->imo_membership[idx] == NULL, + ("%s: imo_membership already allocated", __func__)); imo->imo_membership[idx] = inm; } else { CTR1(KTR_IGMPV3, "%s: merge inm state", __func__); @@ -2295,7 +2291,7 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt CTR1(KTR_IGMPV3, "%s: failed to merge inm state", __func__); IN_MULTI_LIST_UNLOCK(); - goto out_in_multi_locked; + goto out_imf_rollback; } CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__); error = igmp_change_state(inm); @@ -2303,16 +2299,11 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt if (error) { CTR1(KTR_IGMPV3, "%s: failed igmp downcall", __func__); - goto out_in_multi_locked; + goto out_imf_rollback; } } -out_in_multi_locked: - - IN_MULTI_UNLOCK(); - INP_WLOCK(inp); - if (in_pcbrele_wlocked(inp)) - return (ENXIO); +out_imf_rollback: if (error) { imf_rollback(imf); if (is_new) @@ -2337,6 +2328,7 @@ out_imo_free: out_inp_locked: INP_WUNLOCK(inp); + IN_MULTI_UNLOCK(); return (error); } @@ -2463,6 +2455,7 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sop /* * Find the membership in the membership array. */ + IN_MULTI_LOCK(); imo = inp_findmoptions(inp); idx = imo_match_group(imo, ifp, &gsa->sa); if (idx == -1) { @@ -2510,9 +2503,6 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sop /* * Begin state merge transaction at IGMP layer. */ - in_pcbref(inp); - INP_WUNLOCK(inp); - IN_MULTI_LOCK(); if (is_final) { /* @@ -2528,7 +2518,7 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sop CTR1(KTR_IGMPV3, "%s: failed to merge inm state", __func__); IN_MULTI_LIST_UNLOCK(); - goto out_in_multi_locked; + goto out_imf_rollback; } CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__); @@ -2540,13 +2530,7 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sop } } -out_in_multi_locked: - - IN_MULTI_UNLOCK(); - INP_WLOCK(inp); - if (in_pcbrele_wlocked(inp)) - return (ENXIO); - +out_imf_rollback: if (error) imf_rollback(imf); else @@ -2557,7 +2541,7 @@ out_in_multi_locked: if (is_final) { /* Remove the gap in the membership and filter array. */ KASSERT(RB_EMPTY(&imf->imf_sources), - ("%s: imf_sources not empty", __func__)); + ("%s: imf_sources (%p %p %zu) not empty", __func__, imf, imo, idx)); for (++idx; idx < imo->imo_num_memberships; ++idx) { imo->imo_membership[idx - 1] = imo->imo_membership[idx]; imo->imo_mfilters[idx - 1] = imo->imo_mfilters[idx]; @@ -2569,6 +2553,7 @@ out_in_multi_locked: out_inp_locked: INP_WUNLOCK(inp); + IN_MULTI_UNLOCK(); return (error); } @@ -2646,8 +2631,6 @@ inp_set_multicast_if(struct inpcb *inp, struct sockopt /* * Atomically set source filters on a socket for an IPv4 multicast group. - * - * SMPng: NOTE: Potentially calls malloc(M_WAITOK) with Giant held. */ static int inp_set_source_filters(struct inpcb *inp, struct sockopt *sopt) @@ -2694,6 +2677,7 @@ inp_set_source_filters(struct inpcb *inp, struct socko * Take the INP write lock. * Check if this socket is a member of this group. */ + IN_MULTI_LOCK(); imo = inp_findmoptions(inp); idx = imo_match_group(imo, ifp, &gsa->sa); if (idx == -1 || imo->imo_mfilters == NULL) { @@ -2778,7 +2762,6 @@ inp_set_source_filters(struct inpcb *inp, struct socko goto out_imf_rollback; INP_WLOCK_ASSERT(inp); - IN_MULTI_LOCK(); /* * Begin state merge transaction at IGMP layer. @@ -2789,7 +2772,7 @@ inp_set_source_filters(struct inpcb *inp, struct socko if (error) { CTR1(KTR_IGMPV3, "%s: failed to merge inm state", __func__); IN_MULTI_LIST_UNLOCK(); - goto out_in_multi_locked; + goto out_imf_rollback; } CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__); @@ -2798,10 +2781,6 @@ inp_set_source_filters(struct inpcb *inp, struct socko if (error) CTR1(KTR_IGMPV3, "%s: failed igmp downcall", __func__); -out_in_multi_locked: - - IN_MULTI_UNLOCK(); - out_imf_rollback: if (error) imf_rollback(imf); @@ -2812,6 +2791,7 @@ out_imf_rollback: out_inp_locked: INP_WUNLOCK(inp); + IN_MULTI_UNLOCK(); return (error); } Modified: head/sys/netinet6/in6_mcast.c ============================================================================== --- head/sys/netinet6/in6_mcast.c Tue May 14 21:11:15 2019 (r347581) +++ head/sys/netinet6/in6_mcast.c Tue May 14 21:30:55 2019 (r347582) @@ -2052,6 +2052,7 @@ in6p_join_group(struct inpcb *inp, struct sockopt *sop */ (void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL); + IN6_MULTI_LOCK(); imo = in6p_findmoptions(inp); idx = im6o_match_group(imo, ifp, &gsa->sa); if (idx == -1) { @@ -2171,10 +2172,6 @@ in6p_join_group(struct inpcb *inp, struct sockopt *sop /* * Begin state merge transaction at MLD layer. */ - in_pcbref(inp); - INP_WUNLOCK(inp); - IN6_MULTI_LOCK(); - if (is_new) { error = in6_joingroup_locked(ifp, &gsa->sin6.sin6_addr, imf, &inm, 0); @@ -2204,10 +2201,6 @@ in6p_join_group(struct inpcb *inp, struct sockopt *sop IN6_MULTI_LIST_UNLOCK(); } - IN6_MULTI_UNLOCK(); - INP_WLOCK(inp); - if (in_pcbrele_wlocked(inp)) - return (ENXIO); if (error) { im6f_rollback(imf); if (is_new) @@ -2232,6 +2225,7 @@ out_im6o_free: out_in6p_locked: INP_WUNLOCK(inp); + IN6_MULTI_UNLOCK(); in6m_release_list_deferred(&inmh); return (error); } @@ -2381,6 +2375,7 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *so /* * Find the membership in the membership array. */ + IN6_MULTI_LOCK(); imo = in6p_findmoptions(inp); idx = im6o_match_group(imo, ifp, &gsa->sa); if (idx == -1) { @@ -2429,10 +2424,6 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *so /* * Begin state merge transaction at MLD layer. */ - in_pcbref(inp); - INP_WUNLOCK(inp); - IN6_MULTI_LOCK(); - if (is_final) { /* * Give up the multicast address record to which @@ -2456,11 +2447,6 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *so IN6_MULTI_LIST_UNLOCK(); } - IN6_MULTI_UNLOCK(); - INP_WLOCK(inp); - if (in_pcbrele_wlocked(inp)) - return (ENXIO); - if (error) im6f_rollback(imf); else @@ -2483,6 +2469,7 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *so out_in6p_locked: INP_WUNLOCK(inp); + IN6_MULTI_UNLOCK(); return (error); } @@ -2528,8 +2515,6 @@ in6p_set_multicast_if(struct inpcb *inp, struct sockop /* * Atomically set source filters on a socket for an IPv6 multicast group. - * - * SMPng: NOTE: Potentially calls malloc(M_WAITOK) with Giant held. */ static int in6p_set_source_filters(struct inpcb *inp, struct sockopt *sopt)
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