Author: hselasky Date: Mon Apr 22 07:27:24 2019 New Revision: 346530 URL: https://svnweb.freebsd.org/changeset/base/346530
Log: Fix panic in network stack due to memory use after free in relation to fragmented packets. When sending IPv4 and IPv6 fragmented packets and a fragment is lost, the mbuf making up the fragment will remain in the temporary hashed fragment list for a while. If the network interface departs before the so-called slow timeout clears the packet, the fragment causes a panic when the timeout kicks in due to accessing a freed network interface structure. Make sure that when a network device is departing, all hashed IPv4 and IPv6 fragments belonging to it, get freed. Backtrace: panic() icmp6_reflect() hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim; ^^^^ rcvif->if_afdata[AF_INET6] is NULL. icmp6_error() frag6_freef() frag6_slowtimo() pfslowtimo() softclock_call_cc() softclock() ithread_loop() Differential Revision: https://reviews.freebsd.org/D19622 Reviewed by: bz (network), adrian MFC after: 1 week Sponsored by: Mellanox Technologies Modified: head/sys/netinet/ip_reass.c head/sys/netinet6/frag6.c Modified: head/sys/netinet/ip_reass.c ============================================================================== --- head/sys/netinet/ip_reass.c Mon Apr 22 07:17:10 2019 (r346529) +++ head/sys/netinet/ip_reass.c Mon Apr 22 07:27:24 2019 (r346530) @@ -46,7 +46,10 @@ __FBSDID("$FreeBSD$"); #include <sys/lock.h> #include <sys/mutex.h> #include <sys/sysctl.h> +#include <sys/socket.h> +#include <net/if.h> +#include <net/if_var.h> #include <net/rss_config.h> #include <net/netisr.h> #include <net/vnet.h> @@ -605,6 +608,37 @@ ipreass_drain(void) IPQ_UNLOCK(i); } } + +/* + * Drain off all datagram fragments belonging to + * the given network interface. + */ +static void +ipreass_cleanup(void *arg __unused, struct ifnet *ifp) +{ + struct ipq *fp, *temp; + struct mbuf *m; + int i; + + KASSERT(ifp != NULL, ("%s: ifp is NULL", __func__)); + + CURVNET_SET_QUIET(ifp->if_vnet); + for (i = 0; i < IPREASS_NHASH; i++) { + IPQ_LOCK(i); + /* Scan fragment list. */ + TAILQ_FOREACH_SAFE(fp, &V_ipq[i].head, ipq_list, temp) { + for (m = fp->ipq_frags; m != NULL; m = m->m_nextpkt) { + if (m->m_pkthdr.rcvif == ifp) { + ipq_drop(&V_ipq[i], fp); + break; + } + } + } + IPQ_UNLOCK(i); + } + CURVNET_RESTORE(); +} +EVENTHANDLER_DEFINE(ifnet_departure_event, ipreass_cleanup, NULL, 0); #ifdef VIMAGE /* Modified: head/sys/netinet6/frag6.c ============================================================================== --- head/sys/netinet6/frag6.c Mon Apr 22 07:17:10 2019 (r346529) +++ head/sys/netinet6/frag6.c Mon Apr 22 07:27:24 2019 (r346530) @@ -81,7 +81,7 @@ static void frag6_deq(struct ip6asfrag *, uint32_t buc static void frag6_insque_head(struct ip6q *, struct ip6q *, uint32_t bucket); static void frag6_remque(struct ip6q *, uint32_t bucket); -static void frag6_freef(struct ip6q *, uint32_t bucket); +static void frag6_freef(struct ip6q *, uint32_t bucket, bool send_icmp); struct ip6qbucket { struct ip6q ip6q; @@ -594,7 +594,7 @@ insert: if (af6->ip6af_off != next) { if (q6->ip6q_nfrag > V_ip6_maxfragsperpacket) { IP6STAT_ADD(ip6s_fragdropped, q6->ip6q_nfrag); - frag6_freef(q6, hash); + frag6_freef(q6, hash, true); } IP6Q_UNLOCK(hash); return IPPROTO_DONE; @@ -604,7 +604,7 @@ insert: if (af6->ip6af_up->ip6af_mff) { if (q6->ip6q_nfrag > V_ip6_maxfragsperpacket) { IP6STAT_ADD(ip6s_fragdropped, q6->ip6q_nfrag); - frag6_freef(q6, hash); + frag6_freef(q6, hash, true); } IP6Q_UNLOCK(hash); return IPPROTO_DONE; @@ -731,7 +731,7 @@ insert: * associated datagrams. */ static void -frag6_freef(struct ip6q *q6, uint32_t bucket) +frag6_freef(struct ip6q *q6, uint32_t bucket, bool send_icmp) { struct ip6asfrag *af6, *down6; @@ -748,7 +748,7 @@ frag6_freef(struct ip6q *q6, uint32_t bucket) * Return ICMP time exceeded error for the 1st fragment. * Just free other fragments. */ - if (af6->ip6af_off == 0) { + if (af6->ip6af_off == 0 && send_icmp != false) { struct ip6_hdr *ip6; /* adjust pointer */ @@ -864,7 +864,7 @@ frag6_slowtimo(void) IP6STAT_ADD(ip6s_fragtimeout, q6->ip6q_prev->ip6q_nfrag); /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ - frag6_freef(q6->ip6q_prev, i); + frag6_freef(q6->ip6q_prev, i, true); } } /* @@ -883,7 +883,7 @@ frag6_slowtimo(void) IP6STAT_ADD(ip6s_fragoverflow, q6->ip6q_prev->ip6q_nfrag); /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ - frag6_freef(head->ip6q_prev, i); + frag6_freef(head->ip6q_prev, i, true); } IP6Q_UNLOCK(i); } @@ -901,7 +901,7 @@ frag6_slowtimo(void) IP6STAT_ADD(ip6s_fragoverflow, q6->ip6q_prev->ip6q_nfrag); /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ - frag6_freef(head->ip6q_prev, i); + frag6_freef(head->ip6q_prev, i, true); } IP6Q_UNLOCK(i); i = (i + 1) % IP6REASS_NHASH; @@ -931,7 +931,7 @@ frag6_drain(void) while (head->ip6q_next != head) { IP6STAT_INC(ip6s_fragdropped); /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ - frag6_freef(head->ip6q_next, i); + frag6_freef(head->ip6q_next, i, true); } IP6Q_UNLOCK(i); } @@ -939,6 +939,45 @@ frag6_drain(void) } VNET_LIST_RUNLOCK_NOSLEEP(); } + +/* + * Drain off all datagram fragments belonging to + * the given network interface. + */ +static void +frag6_cleanup(void *arg __unused, struct ifnet *ifp) +{ + struct ip6q *q6, *q6n, *head; + struct ip6asfrag *af6; + struct mbuf *m; + int i; + + KASSERT(ifp != NULL, ("%s: ifp is NULL", __func__)); + + CURVNET_SET_QUIET(ifp->if_vnet); + for (i = 0; i < IP6REASS_NHASH; i++) { + IP6Q_LOCK(i); + head = IP6Q_HEAD(i); + /* Scan fragment list. */ + for (q6 = head->ip6q_next; q6 != head; q6 = q6n) { + q6n = q6->ip6q_next; + + for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; + af6 = af6->ip6af_down) { + m = IP6_REASS_MBUF(af6); + + if (m->m_pkthdr.rcvif == ifp) { + IP6STAT_INC(ip6s_fragdropped); + frag6_freef(q6, i, false); + break; + } + } + } + IP6Q_UNLOCK(i); + } + CURVNET_RESTORE(); +} +EVENTHANDLER_DEFINE(ifnet_departure_event, frag6_cleanup, NULL, 0); int ip6_deletefraghdr(struct mbuf *m, int offset, int wait) _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
