/* $NetBSD: ipsec_input.c,v 1.5 2003/09/12 11:20:58 itojun Exp $ */ /* $FreeBSD: src/sys/netipsec/ipsec_input.c,v 1.2.4.1 2003/01/24 05:11:35 sam Exp $ */ /* $KAME: ipsec.c,v 1.103 2001/05/24 07:14:18 sakane Exp $ */ #include __KERNEL_RCSID(0, "$NetBSD: ipsec_input.c,v 1.5 2003/09/12 11:20:58 itojun Exp $"); /* * IPsec input processing. */ #include "opt_inet.h" #ifdef __FreeBSD__ #include "opt_inet6.h" #endif #include "opt_ipsec.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #endif #include #ifdef INET6 #include #endif #include #ifdef INET6 #include #endif #include #include #include #include #include #include #include #include #include #include #include #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \ (p) == IPPROTO_AH ? (y)++ : (z)++) /* * 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) { union sockaddr_union dst_address; struct secasvar *sav; u_int32_t spi; int s, error; IPSEC_ISTAT(sproto, espstat.esps_input, ahstat.ahs_input, ipcompstat.ipcomps_input); IPSEC_ASSERT(m != NULL, ("ipsec_common_input: null packet")); if ((sproto == IPPROTO_ESP && !esp_enable) || (sproto == IPPROTO_AH && !ah_enable) || (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) { m_freem(m); IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops); return EOPNOTSUPP; } if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) { m_freem(m); IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops); DPRINTF(("ipsec_common_input: 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), (caddr_t) &spi); else if (sproto == IPPROTO_AH) m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t), (caddr_t) &spi); else if (sproto == IPPROTO_IPCOMP) { u_int16_t cpi; m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t), (caddr_t) &cpi); spi = ntohl(htons(cpi)); } /* * 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. */ bzero(&dst_address, 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), (caddr_t) &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), (caddr_t) &dst_address.sin6.sin6_addr); break; #endif /* INET6 */ default: DPRINTF(("ipsec_common_input: unsupported protocol " "family %u\n", af)); m_freem(m); IPSEC_ISTAT(sproto, espstat.esps_nopf, ahstat.ahs_nopf, ipcompstat.ipcomps_nopf); return EPFNOSUPPORT; } s = splsoftnet(); /* NB: only pass dst since key_allocsa follows RFC2401 */ sav = KEY_ALLOCSA(&dst_address, sproto, spi); if (sav == NULL) { DPRINTF(("ipsec_common_input: no key association found for" " SA %s/%08lx/%u\n", ipsec_address(&dst_address), (u_long) ntohl(spi), sproto)); IPSEC_ISTAT(sproto, espstat.esps_notdb, ahstat.ahs_notdb, ipcompstat.ipcomps_notdb); splx(s); m_freem(m); return ENOENT; } if (sav->tdb_xform == NULL) { DPRINTF(("ipsec_common_input: attempted to use uninitialized" " SA %s/%08lx/%u\n", ipsec_address(&dst_address), (u_long) ntohl(spi), sproto)); IPSEC_ISTAT(sproto, espstat.esps_noxform, ahstat.ahs_noxform, ipcompstat.ipcomps_noxform); KEY_FREESAV(&sav); splx(s); m_freem(m); return ENXIO; } /* * 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, struct m_tag *mt) { int prot, af, sproto; struct ip *ip; struct m_tag *mtag; struct tdb_ident *tdbi; struct secasindex *saidx; int error; IPSEC_SPLASSERT_SOFTNET("ipsec4_common_input_cb"); IPSEC_ASSERT(m != NULL, ("ipsec4_common_input_cb: null mbuf")); IPSEC_ASSERT(sav != NULL, ("ipsec4_common_input_cb: null SA")); IPSEC_ASSERT(sav->sah != NULL, ("ipsec4_common_input_cb: null SAH")); saidx = &sav->sah->saidx; af = saidx->dst.sa.sa_family; IPSEC_ASSERT(af == AF_INET, ("ipsec4_common_input_cb: unexpected af %u",af)); sproto = saidx->proto; IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH || sproto == IPPROTO_IPCOMP, ("ipsec4_common_input_cb: unexpected security protocol %u", sproto)); /* Sanity check */ if (m == NULL) { DPRINTF(("ipsec4_common_input_cb: null mbuf")); IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr, ipcompstat.ipcomps_badkcr); KEY_FREESAV(&sav); return EINVAL; } if (skip != 0) { /* Fix IPv4 header */ if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) { DPRINTF(("ipsec4_common_input_cb: processing failed " "for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst), (u_long) ntohl(sav->spi))); IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops); error = ENOBUFS; goto bad; } ip = mtod(m, struct ip *); ip->ip_len = htons(m->m_pkthdr.len); #ifdef __FreeBSD__ /* On FreeBSD, ip_off and ip_len assumed in host endian. */ ip->ip_off = htons(ip->ip_off); #endif ip->ip_sum = 0; ip->ip_sum = in_cksum(m, ip->ip_hl << 2); } else { ip = mtod(m, struct ip *); } 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), (caddr_t) &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)) { DPRINTF(("ipsec4_common_input_cb: inner " "source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", inet_ntoa4(ipn.ip_src), ipsp_address(saidx->proxy), ipsp_address(saidx->dst), (u_long) ntohl(sav->spi))); IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops, ipcompstat.ipcomps_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), (caddr_t) &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)) { DPRINTF(("ipsec4_common_input_cb: inner " "source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", ip6_sprintf(&ip6n.ip6_src), ipsec_address(&saidx->proxy), ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops); error = EACCES; goto bad; } #endif /*XXX*/ } #endif /* INET6 */ /* * Record what we've done to the packet (under what SA it was * processed). If we've been passed an mtag, it means the packet * was already processed by an ethernet/crypto combo card and * thus has a tag attached with all the right information, but * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type. */ if (mt == NULL && sproto != IPPROTO_IPCOMP) { mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE, sizeof(struct tdb_ident), M_NOWAIT); if (mtag == NULL) { DPRINTF(("ipsec4_common_input_cb: failed to get tag\n")); IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops); error = ENOMEM; goto bad; } tdbi = (struct tdb_ident *)(mtag + 1); bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len); tdbi->proto = sproto; tdbi->spi = sav->spi; m_tag_prepend(m, mtag); } else { mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE; /* XXX do we need to mark m_flags??? */ } key_sa_recordxfer(sav, m); /* record data transfer */ /* * Re-dispatch via software interrupt. */ if (!IF_HANDOFF(&ipintrq, m, NULL)) { IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull, ipcompstat.ipcomps_qfull); DPRINTF(("ipsec4_common_input_cb: queue full; " "proto %u packet dropped\n", sproto)); return ENOBUFS; } schednetisr(NETISR_IP); 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; struct ip6_ext ip6e; if (*offp < sizeof(struct ip6_hdr)) { DPRINTF(("ipsec6_common_input: bad offset %u\n", *offp)); 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); do { protoff += l; m_copydata(*mp, protoff, sizeof(ip6e), (caddr_t) &ip6e); if (ip6e.ip6e_nxt == IPPROTO_AH) l = (ip6e.ip6e_len + 2) << 2; else l = (ip6e.ip6e_len + 1) << 3; IPSEC_ASSERT(l > 0, ("ah6_input: l went zero or negative")); } while (protoff + l < *offp); /* Malformed packet check */ if (protoff + l != *offp) { DPRINTF(("ipsec6_common_input: bad packet header chain, " "protoff %u, l %u, off %u\n", protoff, l, *offp)); IPSEC_ISTAT(proto, espstat.esps_hdrops, ahstat.ahs_hdrops, ipcompstat.ipcomps_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; } void esp6_ctlinput(int cmd, struct sockaddr *sa, void *d) { if (sa->sa_family != AF_INET6 || sa->sa_len != sizeof(struct sockaddr_in6)) return; if ((unsigned)cmd >= PRC_NCMDS) return; /* if the parameter is from icmp6, decode it. */ if (d != NULL) { struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; struct mbuf *m = ip6cp->ip6c_m; int off = ip6cp->ip6c_off; struct ip6ctlparam ip6cp1; /* * Notify the error to all possible sockets via pfctlinput2. * Since the upper layer information (such as protocol type, * source and destination ports) is embedded in the encrypted * data and might have been cut, we can't directly call * an upper layer ctlinput function. However, the pcbnotify * function will consider source and destination addresses * as well as the flow info value, and may be able to find * some PCB that should be notified. * Although pfctlinput2 will call esp6_ctlinput(), there is * no possibility of an infinite loop of function calls, * because we don't pass the inner IPv6 header. */ bzero(&ip6cp1, sizeof(ip6cp1)); ip6cp1.ip6c_src = ip6cp->ip6c_src; pfctlinput2(cmd, sa, (void *)&ip6cp1); /* * Then go to special cases that need ESP header information. * XXX: We assume that when ip6 is non NULL, * M and OFF are valid. */ if (cmd == PRC_MSGSIZE) { struct secasvar *sav; u_int32_t spi; int valid; /* check header length before using m_copydata */ if (m->m_pkthdr.len < off + sizeof (struct esp)) return; m_copydata(m, off + offsetof(struct esp, esp_spi), sizeof(u_int32_t), (caddr_t) &spi); /* * Check to see if we have a valid SA corresponding to * the address in the ICMP message payload. */ sav = KEY_ALLOCSA((union sockaddr_union *)sa, IPPROTO_ESP, spi); valid = (sav != NULL); if (sav) KEY_FREESAV(&sav); /* XXX Further validation? */ /* * Depending on whether the SA is "valid" and * routing table size (mtudisc_{hi,lo}wat), we will: * - recalcurate the new MTU and create the * corresponding routing entry, or * - ignore the MTU change notification. */ icmp6_mtudisc_update(ip6cp, valid); } } else { /* we normally notify any pcb here */ } } extern 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, struct m_tag *mt) { int prot, af, sproto; struct ip6_hdr *ip6; struct m_tag *mtag; struct tdb_ident *tdbi; struct secasindex *saidx; int nxt; u_int8_t nxt8; int error, nest; IPSEC_ASSERT(m != NULL, ("ipsec6_common_input_cb: null mbuf")); IPSEC_ASSERT(sav != NULL, ("ipsec6_common_input_cb: null SA")); IPSEC_ASSERT(sav->sah != NULL, ("ipsec6_common_input_cb: null SAH")); saidx = &sav->sah->saidx; af = saidx->dst.sa.sa_family; IPSEC_ASSERT(af == AF_INET6, ("ipsec6_common_input_cb: unexpected af %u", af)); sproto = saidx->proto; IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH || sproto == IPPROTO_IPCOMP, ("ipsec6_common_input_cb: unexpected security protocol %u", sproto)); /* Sanity check */ if (m == NULL) { DPRINTF(("ipsec4_common_input_cb: null mbuf")); IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr, ipcompstat.ipcomps_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) { DPRINTF(("ipsec_common_input_cb: processing failed " "for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst), (u_long) ntohl(sav->spi))); IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops, ipcompstat.ipcomps_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, (unsigned char *) &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), (caddr_t) &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)) { DPRINTF(("ipsec_common_input_cb: inner " "source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", inet_ntoa4(ipn.ip_src), ipsec_address(&saidx->proxy), ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); IPSEC_ISTATsproto, (espstat.esps_pdrops, ahstat.ahs_pdrops, ipcompstat.ipcomps_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), (caddr_t) &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)) { DPRINTF(("ipsec_common_input_cb: inner " "source address %s doesn't correspond to " "expected proxy source %s, SA %s/%08lx\n", ip6_sprintf(&ip6n.ip6_src), ipsec_address(&saidx->proxy), ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops); error = EACCES; goto bad; } #endif /*XXX*/ } /* * Record what we've done to the packet (under what SA it was * processed). If we've been passed an mtag, it means the packet * was already processed by an ethernet/crypto combo card and * thus has a tag attached with all the right information, but * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type. */ if (mt == NULL && sproto != IPPROTO_IPCOMP) { mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE, sizeof(struct tdb_ident), M_NOWAIT); if (mtag == NULL) { DPRINTF(("ipsec_common_input_cb: failed to " "get tag\n")); IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops); error = ENOMEM; goto bad; } tdbi = (struct tdb_ident *)(mtag + 1); bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union)); tdbi->proto = sproto; tdbi->spi = sav->spi; m_tag_prepend(m, mtag); } else { mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE; /* XXX do we need to mark m_flags??? */ } key_sa_recordxfer(sav, m); /* Retrieve new protocol */ m_copydata(m, protoff, sizeof(u_int8_t), (caddr_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)) { ip6stat.ip6s_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) { ip6stat.ip6s_tooshort++; in6_ifstat_inc(m->m_pkthdr.rcvif, 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 */