/* $NetBSD: ipsec_input.c,v 1.47 2017/07/07 01:37:34 ozaki-r Exp $ */ /* $FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/sys/netipsec/ipsec_input.c,v 1.2.4.2 2003/03/28 20:32:53 sam Exp $ */ /* $OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $ */ /* * The authors of this code are John Ioannidis (ji@tla.org), * Angelos D. Keromytis (kermit@csd.uch.gr) and * Niels Provos (provos@physnet.uni-hamburg.de). * * This code was written by John Ioannidis for BSD/OS in Athens, Greece, * in November 1995. * * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, * by Angelos D. Keromytis. * * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis * and Niels Provos. * * Additional features in 1999 by Angelos D. Keromytis. * * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, * Angelos D. Keromytis and Niels Provos. * Copyright (c) 2001, Angelos D. Keromytis. * * Permission to use, copy, and modify this software with or without fee * is hereby granted, provided that this entire notice is included in * all copies of any software which is or includes a copy or * modification of this software. * You may use this code under the GNU public license if you so wish. Please * contribute changes back to the authors under this freer than GPL license * so that we may further the use of strong encryption without limitations to * all. * * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR * PURPOSE. */ #include __KERNEL_RCSID(0, "$NetBSD: ipsec_input.c,v 1.47 2017/07/07 01:37:34 ozaki-r Exp $"); /* * IPsec input processing. */ #if defined(_KERNEL_OPT) #include "opt_inet.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #include #include #endif #include #ifdef INET6 #include #endif #include #include #ifdef INET6 #include #endif #include #include #include #include #include #include #include #include #include #define IPSEC_ISTAT(p, x, y, z) \ do { \ switch (p) { \ case IPPROTO_ESP: \ ESP_STATINC(x); \ break; \ case IPPROTO_AH: \ AH_STATINC(y); \ break; \ default: \ IPCOMP_STATINC(z); \ break; \ } \ } while (/*CONSTCOND*/0) /* * fixup TCP/UDP checksum * * XXX: if we have NAT-OA payload from IKE server, * we must do the differential update of checksum. * * XXX: NAT-OAi/NAT-OAr drived from IKE initiator/responder. * how to know the IKE side from kernel? */ static struct mbuf * ipsec4_fixup_checksum(struct mbuf *m) { struct ip *ip; struct tcphdr *th; struct udphdr *uh; int poff, off; int plen; if (m->m_len < sizeof(*ip)) m = m_pullup(m, sizeof(*ip)); ip = mtod(m, struct ip *); poff = ip->ip_hl << 2; plen = ntohs(ip->ip_len) - poff; switch (ip->ip_p) { case IPPROTO_TCP: IP6_EXTHDR_GET(th, struct tcphdr *, m, poff, sizeof(*th)); if (th == NULL) return NULL; off = th->th_off << 2; if (off < sizeof(*th) || off > plen) { m_freem(m); return NULL; } th->th_sum = 0; th->th_sum = in4_cksum(m, IPPROTO_TCP, poff, plen); break; case IPPROTO_UDP: IP6_EXTHDR_GET(uh, struct udphdr *, m, poff, sizeof(*uh)); if (uh == NULL) return NULL; off = sizeof(*uh); if (off > plen) { m_freem(m); return NULL; } uh->uh_sum = 0; uh->uh_sum = in4_cksum(m, IPPROTO_UDP, poff, plen); break; default: /* no checksum */ return m; } return m; } /* * ipsec_common_input gets called when an IPsec-protected packet * is received by IPv4 or IPv6. It's job is to find the right SA # and call the appropriate transform. The transform callback * takes care of further processing (like ingress filtering). */ static int ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto) { char buf[IPSEC_ADDRSTRLEN]; union sockaddr_union dst_address; struct secasvar *sav; u_int32_t spi; u_int16_t sport; u_int16_t dport; int s, error; IPSEC_ISTAT(sproto, ESP_STAT_INPUT, AH_STAT_INPUT, IPCOMP_STAT_INPUT); KASSERT(m != NULL); if ((sproto == IPPROTO_ESP && !esp_enable) || (sproto == IPPROTO_AH && !ah_enable) || (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) { m_freem(m); IPSEC_ISTAT(sproto, ESP_STAT_PDROPS, AH_STAT_PDROPS, IPCOMP_STAT_PDROPS); return EOPNOTSUPP; } if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) { m_freem(m); IPSEC_ISTAT(sproto, ESP_STAT_HDROPS, AH_STAT_HDROPS, IPCOMP_STAT_HDROPS); IPSECLOG(LOG_DEBUG, "packet too small\n"); return EINVAL; } /* Retrieve the SPI from the relevant IPsec header */ if (sproto == IPPROTO_ESP) m_copydata(m, skip, sizeof(u_int32_t), &spi); else if (sproto == IPPROTO_AH) m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t), &spi); else if (sproto == IPPROTO_IPCOMP) { u_int16_t cpi; m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t), &cpi); spi = ntohl(htons(cpi)); } else { panic("ipsec_common_input called with bad protocol number :" "%d\n", sproto); } /* find the source port for NAT-T */ nat_t_ports_get(m, &dport, &sport); /* * Find the SA and (indirectly) call the appropriate * kernel crypto routine. The resulting mbuf chain is a valid * IP packet ready to go through input processing. */ memset(&dst_address, 0, sizeof (dst_address)); dst_address.sa.sa_family = af; switch (af) { #ifdef INET case AF_INET: dst_address.sin.sin_len = sizeof(struct sockaddr_in); m_copydata(m, offsetof(struct ip, ip_dst), sizeof(struct in_addr), &dst_address.sin.sin_addr); break; #endif /* INET */ #ifdef INET6 case AF_INET6: dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6); m_copydata(m, offsetof(struct ip6_hdr, ip6_dst), sizeof(struct in6_addr), &dst_address.sin6.sin6_addr); if (sa6_recoverscope(&dst_address.sin6)) { m_freem(m); return EINVAL; } break; #endif /* INET6 */ default: IPSECLOG(LOG_DEBUG, "unsupported protocol family %u\n", af); m_freem(m); IPSEC_ISTAT(sproto, ESP_STAT_NOPF, AH_STAT_NOPF, IPCOMP_STAT_NOPF); return EPFNOSUPPORT; } s = splsoftnet(); /* NB: only pass dst since key_lookup_sa follows RFC2401 */ sav = KEY_LOOKUP_SA(&dst_address, sproto, spi, sport, dport); if (sav == NULL) { IPSECLOG(LOG_DEBUG, "no key association found for SA %s/%08lx/%u/%u\n", ipsec_address(&dst_address, buf, sizeof(buf)), (u_long) ntohl(spi), sproto, ntohs(dport)); IPSEC_ISTAT(sproto, ESP_STAT_NOTDB, AH_STAT_NOTDB, IPCOMP_STAT_NOTDB); splx(s); m_freem(m); return ENOENT; } KASSERT(sav->tdb_xform != NULL); /* * Call appropriate transform and return -- callback takes care of * everything else. */ error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff); KEY_FREESAV(&sav); splx(s); return error; } #ifdef INET /* * Common input handler for IPv4 AH, ESP, and IPCOMP. */ void ipsec4_common_input(struct mbuf *m, ...) { va_list ap; int off, nxt; va_start(ap, m); off = va_arg(ap, int); nxt = va_arg(ap, int); va_end(ap); (void) ipsec_common_input(m, off, offsetof(struct ip, ip_p), AF_INET, nxt); } /* * IPsec input callback for INET protocols. * This routine is called as the transform callback. * Takes care of filtering and other sanity checks on * the processed packet. */ int ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff) { int prot, af __diagused, sproto; struct ip *ip; struct tdb_ident *tdbi; struct secasindex *saidx; int error; IPSEC_SPLASSERT_SOFTNET("ipsec4_common_input_cb"); KASSERT(m != NULL); KASSERT(sav != NULL); KASSERT(sav->sah != NULL); saidx = &sav->sah->saidx; af = saidx->dst.sa.sa_family; KASSERTMSG(af == AF_INET, "unexpected af %u", af); sproto = saidx->proto; KASSERTMSG(sproto == IPPROTO_ESP || sproto == IPPROTO_AH || sproto == IPPROTO_IPCOMP, "unexpected security protocol %u", sproto); /* Sanity check */ if (m == NULL) { IPSECLOG(LOG_DEBUG, "null mbuf"); IPSEC_ISTAT(sproto, ESP_STAT_BADKCR, AH_STAT_BADKCR, IPCOMP_STAT_BADKCR); KEY_FREESAV(&sav); return EINVAL; } /* Fix IPv4 header */ if (skip != 0) { if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) { char buf[IPSEC_ADDRSTRLEN]; cantpull: IPSECLOG(LOG_DEBUG, "processing failed for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); IPSEC_ISTAT(sproto, ESP_STAT_HDROPS, AH_STAT_HDROPS, IPCOMP_STAT_HDROPS); error = ENOBUFS; goto bad; } ip = mtod(m, struct ip *); ip->ip_len = htons(m->m_pkthdr.len); ip->ip_sum = 0; ip->ip_sum = in_cksum(m, ip->ip_hl << 2); } else { ip = mtod(m, struct ip *); } /* * Update TCP/UDP checksum * XXX: should only do it in NAT-T case * XXX: should do it incrementally, see FreeBSD code. */ m = ipsec4_fixup_checksum(m); if (m == NULL) goto cantpull; prot = ip->ip_p; /* IP-in-IP encapsulation */ if (prot == IPPROTO_IPIP) { struct ip ipn; /* ipn will now contain the inner IPv4 header */ m_copydata(m, ip->ip_hl << 2, sizeof(struct ip), &ipn); #ifdef notyet /* XXX PROXY address isn't recorded in SAH */ /* * Check that the inner source address is the same as * the proxy address, if available. */ if ((saidx->proxy.sa.sa_family == AF_INET && saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY && ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) || (saidx->proxy.sa.sa_family != AF_INET && saidx->proxy.sa.sa_family != 0)) { char ipbuf[INET_ADDRSTRLEN]; IPSECLOG(LOG_DEBUG, "inner source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", IN_PRINT(ipbuf, ipn.ip_src), ipsp_address(saidx->proxy), ipsp_address(saidx->dst), (u_long) ntohl(sav->spi)); IPSEC_ISTAT(sproto, ESP_STAT_PDROPS, AH_STAT_PDROPS, IPCOMP_STAT_PDROPS); error = EACCES; goto bad; } #endif /*XXX*/ } #if INET6 /* IPv6-in-IP encapsulation. */ if (prot == IPPROTO_IPV6) { struct ip6_hdr ip6n; /* ip6n will now contain the inner IPv6 header. */ m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr), &ip6n); #ifdef notyet /* * Check that the inner source address is the same as * the proxy address, if available. */ if ((saidx->proxy.sa.sa_family == AF_INET6 && !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) && !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src, &saidx->proxy.sin6.sin6_addr)) || (saidx->proxy.sa.sa_family != AF_INET6 && saidx->proxy.sa.sa_family != 0)) { char ip6buf[INET6_ADDRSTRLEN]; char pbuf[IPSEC_ADDRSTRLEN], dbuf[IPSEC_ADDRSTRLEN]; IPSECLOG(LOG_DEBUG, "inner source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", ip6_sprintf(ip6buf, &ip6n.ip6_src), ipsec_address(&saidx->proxy, pbuf, sizeof(pbuf)), ipsec_address(&saidx->dst, dbuf, sizeof(dbuf)), (u_long) ntohl(sav->spi)); IPSEC_ISTAT(sproto, ESP_STAT_PDROPS, AH_STAT_PDROPS, IPCOMP_STAT_PDROPS); error = EACCES; goto bad; } #endif /*XXX*/ } #endif /* INET6 */ /* * Record what we've done to the packet (under what SA it was * processed). */ if (sproto != IPPROTO_IPCOMP) { struct m_tag *mtag; mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE, sizeof(struct tdb_ident), M_NOWAIT); if (mtag == NULL) { IPSECLOG(LOG_DEBUG, "failed to get tag\n"); IPSEC_ISTAT(sproto, ESP_STAT_HDROPS, AH_STAT_HDROPS, IPCOMP_STAT_HDROPS); error = ENOMEM; goto bad; } tdbi = (struct tdb_ident *)(mtag + 1); memcpy(&tdbi->dst, &saidx->dst, saidx->dst.sa.sa_len); tdbi->proto = sproto; tdbi->spi = sav->spi; m_tag_prepend(m, mtag); } key_sa_recordxfer(sav, m); /* record data transfer */ if ((inetsw[ip_protox[prot]].pr_flags & PR_LASTHDR) != 0 && ipsec4_in_reject(m, NULL)) { error = EINVAL; goto bad; } (*inetsw[ip_protox[prot]].pr_input)(m, skip, prot); return 0; bad: m_freem(m); return error; } #endif /* INET */ #ifdef INET6 /* IPv6 AH wrapper. */ int ipsec6_common_input(struct mbuf **mp, int *offp, int proto) { int l = 0; int protoff, nxt; struct ip6_ext ip6e; if (*offp < sizeof(struct ip6_hdr)) { IPSECLOG(LOG_DEBUG, "bad offset %u\n", *offp); IPSEC_ISTAT(proto, ESP_STAT_HDROPS, AH_STAT_HDROPS, IPCOMP_STAT_HDROPS); m_freem(*mp); return IPPROTO_DONE; } else if (*offp == sizeof(struct ip6_hdr)) { protoff = offsetof(struct ip6_hdr, ip6_nxt); } else { /* Chase down the header chain... */ protoff = sizeof(struct ip6_hdr); nxt = (mtod(*mp, struct ip6_hdr *))->ip6_nxt; do { protoff += l; m_copydata(*mp, protoff, sizeof(ip6e), &ip6e); if (nxt == IPPROTO_AH) l = (ip6e.ip6e_len + 2) << 2; else l = (ip6e.ip6e_len + 1) << 3; KASSERT(l > 0); nxt = ip6e.ip6e_nxt; } while (protoff + l < *offp); /* Malformed packet check */ if (protoff + l != *offp) { IPSECLOG(LOG_DEBUG, "bad packet header chain, " "protoff %u, l %u, off %u\n", protoff, l, *offp); IPSEC_ISTAT(proto, ESP_STAT_HDROPS, AH_STAT_HDROPS, IPCOMP_STAT_HDROPS); m_freem(*mp); *mp = NULL; return IPPROTO_DONE; } protoff += offsetof(struct ip6_ext, ip6e_nxt); } (void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto); return IPPROTO_DONE; } extern const struct ip6protosw inet6sw[]; extern u_char ip6_protox[]; /* * IPsec input callback, called by the transform callback. Takes care of * filtering and other sanity checks on the processed packet. */ int ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff) { int af __diagused, sproto; struct ip6_hdr *ip6; struct tdb_ident *tdbi; struct secasindex *saidx; int nxt; u_int8_t prot, nxt8; int error, nest; KASSERT(m != NULL); KASSERT(sav != NULL); KASSERT(sav->sah != NULL); saidx = &sav->sah->saidx; af = saidx->dst.sa.sa_family; KASSERTMSG(af == AF_INET6, "unexpected af %u", af); sproto = saidx->proto; KASSERTMSG(sproto == IPPROTO_ESP || sproto == IPPROTO_AH || sproto == IPPROTO_IPCOMP, "unexpected security protocol %u", sproto); /* Sanity check */ if (m == NULL) { IPSECLOG(LOG_DEBUG, "null mbuf"); IPSEC_ISTAT(sproto, ESP_STAT_BADKCR, AH_STAT_BADKCR, IPCOMP_STAT_BADKCR); error = EINVAL; goto bad; } /* Fix IPv6 header */ if (m->m_len < sizeof(struct ip6_hdr) && (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) { char buf[IPSEC_ADDRSTRLEN]; IPSECLOG(LOG_DEBUG, "processing failed for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); IPSEC_ISTAT(sproto, ESP_STAT_HDROPS, AH_STAT_HDROPS, IPCOMP_STAT_HDROPS); error = EACCES; goto bad; } ip6 = mtod(m, struct ip6_hdr *); ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr)); /* Save protocol */ m_copydata(m, protoff, 1, &prot); #ifdef INET /* IP-in-IP encapsulation */ if (prot == IPPROTO_IPIP) { struct ip ipn; /* ipn will now contain the inner IPv4 header */ m_copydata(m, skip, sizeof(struct ip), &ipn); #ifdef notyet /* * Check that the inner source address is the same as * the proxy address, if available. */ if ((saidx->proxy.sa.sa_family == AF_INET && saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY && ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) || (saidx->proxy.sa.sa_family != AF_INET && saidx->proxy.sa.sa_family != 0)) { char ipbuf[INET_ADDRSTRLEN]; char pbuf[IPSEC_ADDRSTRLEN], dbuf[IPSEC_ADDRSTRLEN]; IPSECLOG(LOG_DEBUG, "inner source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", IN_PRINT(ipbuf, ipn.ip_src), ipsec_address(&saidx->proxy, pbuf, sizeof(pbuf)), ipsec_address(&saidx->dst, dbuf, sizeof(dbuf)), (u_long) ntohl(sav->spi)); IPSEC_ISTAT(sproto, ESP_STAT_PDROPS, AH_STAT_PDROPS, IPCOMP_STAT_PDROPS); error = EACCES; goto bad; } #endif /*XXX*/ } #endif /* INET */ /* IPv6-in-IP encapsulation */ if (prot == IPPROTO_IPV6) { struct ip6_hdr ip6n; /* ip6n will now contain the inner IPv6 header. */ m_copydata(m, skip, sizeof(struct ip6_hdr), &ip6n); #ifdef notyet /* * Check that the inner source address is the same as * the proxy address, if available. */ if ((saidx->proxy.sa.sa_family == AF_INET6 && !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) && !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src, &saidx->proxy.sin6.sin6_addr)) || (saidx->proxy.sa.sa_family != AF_INET6 && saidx->proxy.sa.sa_family != 0)) { char ip6buf[INET6_ADDRSTRLEN]; char pbuf[IPSEC_ADDRSTRLEN], dbuf[IPSEC_ADDRSTRLEN]; IPSECLOG(LOG_DEBUG, "inner source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", ip6_sprintf(ip6buf, &ip6n.ip6_src), ipsec_address(&saidx->proxy, pbuf, sizeof(pbuf)), ipsec_address(&saidx->dst, dbuf, sizeof(dbuf)), (u_long) ntohl(sav->spi)); IPSEC_ISTAT(sproto, ESP_STAT_PDROPS, AH_STAT_PDROPS, IPCOMP_STAT_PDROPS); error = EACCES; goto bad; } #endif /*XXX*/ } /* * Record what we've done to the packet (under what SA it was * processed). */ if (sproto != IPPROTO_IPCOMP) { struct m_tag *mtag; mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE, sizeof(struct tdb_ident), M_NOWAIT); if (mtag == NULL) { IPSECLOG(LOG_DEBUG, "failed to get tag\n"); IPSEC_ISTAT(sproto, ESP_STAT_HDROPS, AH_STAT_HDROPS, IPCOMP_STAT_HDROPS); error = ENOMEM; goto bad; } tdbi = (struct tdb_ident *)(mtag + 1); memcpy(&tdbi->dst, &saidx->dst, sizeof(union sockaddr_union)); tdbi->proto = sproto; tdbi->spi = sav->spi; m_tag_prepend(m, mtag); } key_sa_recordxfer(sav, m); /* Retrieve new protocol */ m_copydata(m, protoff, sizeof(u_int8_t), &nxt8); /* * See the end of ip6_input for this logic. * IPPROTO_IPV[46] case will be processed just like other ones */ nest = 0; nxt = nxt8; while (nxt != IPPROTO_DONE) { if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) { IP6_STATINC(IP6_STAT_TOOMANYHDR); error = EINVAL; goto bad; } /* * Protection against faulty packet - there should be * more sanity checks in header chain processing. */ if (m->m_pkthdr.len < skip) { IP6_STATINC(IP6_STAT_TOOSHORT); in6_ifstat_inc(m_get_rcvif_NOMPSAFE(m), ifs6_in_truncated); error = EINVAL; goto bad; } /* * 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 ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && ipsec6_in_reject(m, NULL)) { error = EINVAL; goto bad; } nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt); } return 0; bad: if (m) m_freem(m); return error; } #endif /* INET6 */