/*- * Copyright (c) 1982, 1986, 1988, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #include "opt_ipsec.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef IPSEC #include #include #include #endif /*IPSEC*/ extern struct protosw inetsw[]; /* * Check if we have to jump over firewall processing for this packet. * Called from ip_input(). * 1 = jump over firewall, 0 = packet goes through firewall. */ int ip_ipsec_filtertunnel(struct mbuf *m) { #if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL) /* * Bypass packet filtering for packets from a tunnel. */ if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) return 1; #endif return 0; } /* * Check if this packet has an active SA and needs to be dropped instead * of forwarded. * Called from ip_input(). * 1 = drop packet, 0 = forward packet. */ int ip_ipsec_fwd(struct mbuf *m) { #ifdef IPSEC struct m_tag *mtag; struct tdb_ident *tdbi; struct secpolicy *sp; int s, error; mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); s = splnet(); if (mtag != NULL) { tdbi = (struct tdb_ident *)(mtag + 1); sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); } else { sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, IP_FORWARDING, &error); } if (sp == NULL) { /* NB: can happen if error */ splx(s); /*XXX error stat???*/ DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ return 1; } /* * Check security policy against packet attributes. */ error = ipsec_in_reject(sp, m); KEY_FREESP(&sp); splx(s); if (error) { ipstat.ips_cantforward++; return 1; } #endif /* IPSEC */ return 0; } /* * Check if protocol type doesn't have a further header and do IPSEC * decryption or reject right now. Protocols with further headers get * their IPSEC treatment within the protocol specific processing. * Called from ip_input(). * 1 = drop packet, 0 = continue processing packet. */ int ip_ipsec_input(struct mbuf *m) { struct ip *ip = mtod(m, struct ip *); #ifdef IPSEC struct m_tag *mtag; struct tdb_ident *tdbi; struct secpolicy *sp; int s, error; /* * enforce IPsec policy checking if we are seeing last header. * note that we do not visit this with protocols with pcb layer * code - like udp/tcp/raw ip. */ if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { /* * Check if the packet has already had IPsec processing * done. If so, then just pass it along. This tag gets * set during AH, ESP, etc. input handling, before the * packet is returned to the ip input queue for delivery. */ mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); s = splnet(); if (mtag != NULL) { tdbi = (struct tdb_ident *)(mtag + 1); sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); } else { sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, IP_FORWARDING, &error); } if (sp != NULL) { /* * Check security policy against packet attributes. */ error = ipsec_in_reject(sp, m); KEY_FREESP(&sp); } else { /* XXX error stat??? */ error = EINVAL; DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ return 1; } splx(s); if (error) return 1; } #endif /* IPSEC */ return 0; } /* * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. * Called from ip_forward(). * Returns MTU suggestion for ICMP needfrag reply. */ int ip_ipsec_mtu(struct mbuf *m) { int mtu = 0; /* * If the packet is routed over IPsec tunnel, tell the * originator the tunnel MTU. * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz * XXX quickhack!!! */ struct secpolicy *sp = NULL; int ipsecerror; int ipsechdr; struct route *ro; sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING, &ipsecerror); if (sp != NULL) { /* count IPsec header size */ ipsechdr = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); /* * find the correct route for outer IPv4 * header, compute tunnel MTU. */ if (sp->req != NULL && sp->req->sav != NULL && sp->req->sav->sah != NULL) { ro = &sp->req->sav->sah->sa_route; if (ro->ro_rt && ro->ro_rt->rt_ifp) { mtu = ro->ro_rt->rt_rmx.rmx_mtu ? ro->ro_rt->rt_rmx.rmx_mtu : ro->ro_rt->rt_ifp->if_mtu; mtu -= ipsechdr; } } KEY_FREESP(&sp); } return mtu; } /* * * Called from ip_output(). * 1 = drop packet, 0 = continue processing packet, * -1 = packet was reinjected and stop processing packet */ int ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, struct route **ro, struct route *iproute, struct sockaddr_in **dst, struct in_ifaddr **ia, struct ifnet **ifp) { #ifdef IPSEC struct secpolicy *sp = NULL; struct ip *ip = mtod(*m, struct ip *); struct tdb_ident *tdbi; struct m_tag *mtag; int s; /* * Check the security policy (SP) for the packet and, if * required, do IPsec-related processing. There are two * cases here; the first time a packet is sent through * it will be untagged and handled by ipsec4_checkpolicy. * If the packet is resubmitted to ip_output (e.g. after * AH, ESP, etc. processing), there will be a tag to bypass * the lookup and related policy checking. */ mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); s = splnet(); if (mtag != NULL) { tdbi = (struct tdb_ident *)(mtag + 1); sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); if (sp == NULL) *error = -EINVAL; /* force silent drop */ m_tag_delete(*m, mtag); } else { sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, error, inp); } /* * There are four return cases: * sp != NULL apply IPsec policy * sp == NULL, error == 0 no IPsec handling needed * sp == NULL, error == -EINVAL discard packet w/o error * sp == NULL, error != 0 discard packet, report error */ if (sp != NULL) { /* Loop detection, check if ipsec processing already done */ KASSERT(sp->req != NULL, ("ip_output: no ipsec request")); for (mtag = m_tag_first(*m); mtag != NULL; mtag = m_tag_next(*m, mtag)) { if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) continue; if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) continue; /* * Check if policy has an SA associated with it. * This can happen when an SP has yet to acquire * an SA; e.g. on first reference. If it occurs, * then we let ipsec4_process_packet do its thing. */ if (sp->req->sav == NULL) break; tdbi = (struct tdb_ident *)(mtag + 1); if (tdbi->spi == sp->req->sav->spi && tdbi->proto == sp->req->sav->sah->saidx.proto && bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst, sizeof (union sockaddr_union)) == 0) { /* * No IPsec processing is needed, free * reference to SP. * * NB: null pointer to avoid free at * done: below. */ KEY_FREESP(&sp), sp = NULL; splx(s); goto done; } } /* * Do delayed checksums now because we send before * this is done in the normal processing path. */ if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { in_delayed_cksum(*m); (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; } ip->ip_len = htons(ip->ip_len); ip->ip_off = htons(ip->ip_off); /* NB: callee frees mbuf */ *error = ipsec4_process_packet(*m, sp->req, *flags, 0); /* * Preserve KAME behaviour: ENOENT can be returned * when an SA acquire is in progress. Don't propagate * this to user-level; it confuses applications. * * XXX this will go away when the SADB is redone. */ if (*error == ENOENT) *error = 0; splx(s); goto reinjected; } else { /* sp == NULL */ splx(s); if (*error != 0) { /* * Hack: -EINVAL is used to signal that a packet * should be silently discarded. This is typically * because we asked key management for an SA and * it was delayed (e.g. kicked up to IKE). */ if (*error == -EINVAL) *error = 0; goto bad; } else { /* No IPsec processing for this packet. */ } #ifdef notyet /* * If deferred crypto processing is needed, check that * the interface supports it. */ mtag = m_tag_find(*m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL); if (mtag != NULL && ((*ifp)->if_capenable & IFCAP_IPSEC) == 0) { /* notify IPsec to do its own crypto */ ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1)); *error = EHOSTUNREACH; goto bad; } #endif } done: if (sp != NULL) KEY_FREESP(&sp); return 0; reinjected: if (sp != NULL) KEY_FREESP(&sp); return -1; bad: if (sp != NULL) KEY_FREESP(&sp); return 1; #endif /* IPSEC */ return 0; }