/* $FreeBSD$ */ /* $KAME: ipsec.c,v 1.103 2001/05/24 07:14:18 sakane Exp $ */ /* * IPsec output processing. */ #include "opt_inet.h" #include "opt_inet6.h" #include "opt_ipsec.h" #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 #ifdef INET6 #include #endif #include #include #include #include #include #include #include #include int ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr) { struct tdb_ident *tdbi; struct m_tag *mtag; struct secasvar *sav; struct secasindex *saidx; int error; #if 0 SPLASSERT(net, "ipsec_process_done"); #endif KASSERT(m != NULL, ("ipsec_process_done: null mbuf")); KASSERT(isr != NULL, ("ipsec_process_done: null ISR")); sav = isr->sav; KASSERT(sav != NULL, ("ipsec_process_done: null SA")); KASSERT(sav->sah != NULL, ("ipsec_process_done: null SAH")); saidx = &sav->sah->saidx; switch (saidx->dst.sa.sa_family) { #ifdef INET case AF_INET: /* Fix the header length, for AH processing. */ mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len); break; #endif /* INET */ #ifdef INET6 case AF_INET6: /* Fix the header length, for AH processing. */ if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) { error = ENXIO; goto bad; } if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) { /* No jumbogram support. */ error = ENXIO; /*?*/ goto bad; } mtod(m, struct ip6_hdr *)->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr)); break; #endif /* INET6 */ default: DPRINTF(("ipsec_process_done: unknown protocol family %u\n", saidx->dst.sa.sa_family)); error = ENXIO; goto bad; } /* * Add a record of what we've done or what needs to be done to the * packet. */ mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(struct tdb_ident), M_NOWAIT); if (mtag == NULL) { DPRINTF(("ipsec_process_done: could not get packet tag\n")); error = ENOMEM; goto bad; } tdbi = (struct tdb_ident *)(mtag + 1); tdbi->dst = saidx->dst; tdbi->proto = saidx->proto; tdbi->spi = sav->spi; m_tag_prepend(m, mtag); /* * If there's another (bundled) SA to apply, do so. * Note that this puts a burden on the kernel stack size. * If this is a problem we'll need to introduce a queue * to set the packet on so we can unwind the stack before * doing further processing. */ if (isr->next) { newipsecstat.ips_out_bundlesa++; return ipsec4_process_packet(m, isr->next, 0, 0); } /* * We're done with IPsec processing, transmit the packet using the * appropriate network protocol (IP or IPv6). SPD lookup will be * performed again there. */ switch (saidx->dst.sa.sa_family) { #ifdef INET struct ip *ip; case AF_INET: ip = mtod(m, struct ip *); ip->ip_len = ntohs(ip->ip_len); ip->ip_off = ntohs(ip->ip_off); return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL); #endif /* INET */ #ifdef INET6 case AF_INET6: /* * We don't need massage, IPv6 header fields are always in * net endian. */ return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); #endif /* INET6 */ } panic("ipsec_process_done"); bad: m_freem(m); KEY_FREESAV(&sav); return (error); } static struct ipsecrequest * ipsec_nextisr( struct mbuf *m, struct ipsecrequest *isr, int af, struct secasindex *saidx, int *error ) { #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \ isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++) struct secasvar *sav; #if 0 SPLASSERT(net, "ipsec_nextisr"); #endif KASSERT(af == AF_INET || af == AF_INET6, ("ipsec_nextisr: invalid address family %u", af)); again: /* * Craft SA index to search for proper SA. Note that * we only fillin unspecified SA peers for transport * mode; for tunnel mode they must already be filled in. */ *saidx = isr->saidx; if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) { /* Fillin unspecified SA peers only for transport mode */ if (af == AF_INET) { struct sockaddr_in *sin; struct ip *ip = mtod(m, struct ip *); if (saidx->src.sa.sa_len == 0) { sin = &saidx->src.sin; sin->sin_len = sizeof(*sin); sin->sin_family = AF_INET; sin->sin_port = IPSEC_PORT_ANY; sin->sin_addr = ip->ip_src; } if (saidx->dst.sa.sa_len == 0) { sin = &saidx->dst.sin; sin->sin_len = sizeof(*sin); sin->sin_family = AF_INET; sin->sin_port = IPSEC_PORT_ANY; sin->sin_addr = ip->ip_dst; } } else { struct sockaddr_in6 *sin6; struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); if (saidx->src.sin6.sin6_len == 0) { sin6 = (struct sockaddr_in6 *)&saidx->src; sin6->sin6_len = sizeof(*sin6); sin6->sin6_family = AF_INET6; sin6->sin6_port = IPSEC_PORT_ANY; sin6->sin6_addr = ip6->ip6_src; if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { /* fix scope id for comparing SPD */ sin6->sin6_addr.s6_addr16[1] = 0; sin6->sin6_scope_id = ntohs(ip6->ip6_src.s6_addr16[1]); } } if (saidx->dst.sin6.sin6_len == 0) { sin6 = (struct sockaddr_in6 *)&saidx->dst; sin6->sin6_len = sizeof(*sin6); sin6->sin6_family = AF_INET6; sin6->sin6_port = IPSEC_PORT_ANY; sin6->sin6_addr = ip6->ip6_dst; if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { /* fix scope id for comparing SPD */ sin6->sin6_addr.s6_addr16[1] = 0; sin6->sin6_scope_id = ntohs(ip6->ip6_dst.s6_addr16[1]); } } } } /* * Lookup SA and validate it. */ *error = key_checkrequest(isr, saidx); if (*error != 0) { /* * IPsec processing is required, but no SA found. * I assume that key_acquire() had been called * to get/establish the SA. Here I discard * this packet because it is responsibility for * upper layer to retransmit the packet. */ newipsecstat.ips_out_nosa++; goto bad; } sav = isr->sav; if (sav == NULL) { /* XXX valid return */ KASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE, ("ipsec_nextisr: no SA found, but required; level %u", ipsec_get_reqlevel(isr))); isr = isr->next; if (isr == NULL) { /*XXXstatistic??*/ *error = EINVAL; /*XXX*/ return isr; } goto again; } /* * Check system global policy controls. */ if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) || (isr->saidx.proto == IPPROTO_AH && !ah_enable) || (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) { DPRINTF(("ipsec_nextisr: IPsec outbound packet dropped due" " to policy (check your sysctls)\n")); IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops); *error = EHOSTUNREACH; goto bad; } /* * Sanity check the SA contents for the caller * before they invoke the xform output method. */ if (sav->tdb_xform == NULL) { DPRINTF(("ipsec_nextisr: no transform for SA\n")); IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform, ipcompstat.ipcomps_noxform); *error = EHOSTUNREACH; goto bad; } return isr; bad: KASSERT(*error != 0, ("ipsec_nextisr: error return w/ no error code")); return NULL; #undef IPSEC_OSTAT } #ifdef INET /* * IPsec output logic for IPv4. */ int ipsec4_process_packet( struct mbuf *m, struct ipsecrequest *isr, int flags, int tunalready) { struct secasindex saidx; struct secasvar *sav; struct ip *ip; int s, error, i, off; KASSERT(m != NULL, ("ipsec4_process_packet: null mbuf")); KASSERT(isr != NULL, ("ipsec4_process_packet: null isr")); s = splnet(); /* insure SA contents don't change */ isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error); if (isr == NULL) goto bad; sav = isr->sav; if (!tunalready) { union sockaddr_union *dst = &sav->sah->saidx.dst; int setdf; /* * Collect IP_DF state from the outer header. */ if (dst->sa.sa_family == AF_INET) { if (m->m_len < sizeof (struct ip) && (m = m_pullup(m, sizeof (struct ip))) == NULL) { error = ENOBUFS; goto bad; } ip = mtod(m, struct ip *); /* Honor system-wide control of how to handle IP_DF */ switch (ip4_ipsec_dfbit) { case 0: /* clear in outer header */ case 1: /* set in outer header */ setdf = ip4_ipsec_dfbit; break; default: /* propagate to outer header */ setdf = ntohs(ip->ip_off & IP_DF); break; } } else { ip = NULL; /* keep compiler happy */ setdf = 0; } /* Do the appropriate encapsulation, if necessary */ if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */ dst->sa.sa_family != AF_INET || /* PF mismatch */ #if 0 (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */ sav->tdb_xform->xf_type == XF_IP4 || /* ditto */ #endif (dst->sa.sa_family == AF_INET && /* Proxy */ dst->sin.sin_addr.s_addr != INADDR_ANY && dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) { struct mbuf *mp; /* Fix IPv4 header checksum and length */ if (m->m_len < sizeof (struct ip) && (m = m_pullup(m, sizeof (struct ip))) == NULL) { error = ENOBUFS; goto bad; } ip = mtod(m, struct ip *); ip->ip_len = htons(m->m_pkthdr.len); ip->ip_sum = 0; #ifdef _IP_VHL if (ip->ip_vhl == IP_VHL_BORING) ip->ip_sum = in_cksum_hdr(ip); else ip->ip_sum = in_cksum(m, _IP_VHL_HL(ip->ip_vhl) << 2); #else ip->ip_sum = in_cksum(m, ip->ip_hl << 2); #endif /* Encapsulate the packet */ error = ipip_output(m, isr, &mp, 0, 0); if (mp == NULL && !error) { /* Should never happen. */ DPRINTF(("ipsec4_process_packet: ipip_output " "returns no mbuf and no error!")); error = EFAULT; } if (error) { if (mp) m_freem(mp); goto bad; } m = mp, mp = NULL; /* * ipip_output clears IP_DF in the new header. If * we need to propagate IP_DF from the outer header, * then we have to do it here. * * XXX shouldn't assume what ipip_output does. */ if (dst->sa.sa_family == AF_INET && setdf) { if (m->m_len < sizeof (struct ip) && (m = m_pullup(m, sizeof (struct ip))) == NULL) { error = ENOBUFS; goto bad; } ip = mtod(m, struct ip *); ip->ip_off = ntohs(ip->ip_off); ip->ip_off |= IP_DF; ip->ip_off = htons(ip->ip_off); } } } /* * Dispatch to the appropriate IPsec transform logic. The * packet will be returned for transmission after crypto * processing, etc. are completed. For encapsulation we * bypass this call because of the explicit call done above * (necessary to deal with IP_DF handling for IPv4). * * NB: m & sav are ``passed to caller'' who's reponsible for * for reclaiming their resources. */ if (sav->tdb_xform->xf_type != XF_IP4) { ip = mtod(m, struct ip *); i = ip->ip_hl << 2; off = offsetof(struct ip, ip_p); error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off); } else { error = ipsec_process_done(m, isr); } splx(s); return error; bad: splx(s); if (m) m_freem(m); return error; } #endif #ifdef INET6 /* * Chop IP6 header from the payload. */ static struct mbuf * ipsec6_splithdr(struct mbuf *m) { struct mbuf *mh; struct ip6_hdr *ip6; int hlen; KASSERT(m->m_len >= sizeof (struct ip6_hdr), ("ipsec6_splithdr: first mbuf too short, len %u", m->m_len)); ip6 = mtod(m, struct ip6_hdr *); hlen = sizeof(struct ip6_hdr); if (m->m_len > hlen) { MGETHDR(mh, M_DONTWAIT, MT_HEADER); if (!mh) { m_freem(m); return NULL; } M_MOVE_PKTHDR(mh, m); MH_ALIGN(mh, hlen); m->m_len -= hlen; m->m_data += hlen; mh->m_next = m; m = mh; m->m_len = hlen; bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen); } else if (m->m_len < hlen) { m = m_pullup(m, hlen); if (!m) return NULL; } return m; } /* * IPsec output logic for IPv6, transport mode. */ int ipsec6_output_trans( struct ipsec_output_state *state, u_char *nexthdrp, struct mbuf *mprev, struct secpolicy *sp, int flags, int *tun) { struct ipsecrequest *isr; struct secasindex saidx; int error = 0; struct mbuf *m; KASSERT(state != NULL, ("ipsec6_output: null state")); KASSERT(state->m != NULL, ("ipsec6_output: null m")); KASSERT(nexthdrp != NULL, ("ipsec6_output: null nexthdrp")); KASSERT(mprev != NULL, ("ipsec6_output: null mprev")); KASSERT(sp != NULL, ("ipsec6_output: null sp")); KASSERT(tun != NULL, ("ipsec6_output: null tun")); KEYDEBUG(KEYDEBUG_IPSEC_DATA, printf("ipsec6_output_trans: applyed SP\n"); kdebug_secpolicy(sp)); isr = sp->req; if (isr->saidx.mode == IPSEC_MODE_TUNNEL) { /* the rest will be handled by ipsec6_output_tunnel() */ *tun = 1; /* need tunnel-mode processing */ return 0; } *tun = 0; m = state->m; isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error); if (isr == NULL) { #ifdef notdef /* XXX should notification be done for all errors ? */ /* * Notify the fact that the packet is discarded * to ourselves. I believe this is better than * just silently discarding. (jinmei@kame.net) * XXX: should we restrict the error to TCP packets? * XXX: should we directly notify sockets via * pfctlinputs? */ icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN, 0); m = NULL; /* NB: icmp6_error frees mbuf */ #endif goto bad; } return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL, sizeof (struct ip6_hdr), offsetof(struct ip6_hdr, ip6_nxt)); bad: if (m) m_freem(m); state->m = NULL; return error; } static int ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav) { struct ip6_hdr *oip6; struct ip6_hdr *ip6; size_t plen; /* can't tunnel between different AFs */ if (sav->sah->saidx.src.sa.sa_family != AF_INET6 || sav->sah->saidx.dst.sa.sa_family != AF_INET6) { m_freem(m); return EINVAL; } KASSERT(m->m_len != sizeof (struct ip6_hdr), ("ipsec6_encapsulate: mbuf wrong size; len %u", m->m_len)); /* * grow the mbuf to accomodate the new IPv6 header. */ plen = m->m_pkthdr.len; if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) { struct mbuf *n; MGET(n, M_DONTWAIT, MT_DATA); if (!n) { m_freem(m); return ENOBUFS; } n->m_len = sizeof(struct ip6_hdr); n->m_next = m->m_next; m->m_next = n; m->m_pkthdr.len += sizeof(struct ip6_hdr); oip6 = mtod(n, struct ip6_hdr *); } else { m->m_next->m_len += sizeof(struct ip6_hdr); m->m_next->m_data -= sizeof(struct ip6_hdr); m->m_pkthdr.len += sizeof(struct ip6_hdr); oip6 = mtod(m->m_next, struct ip6_hdr *); } ip6 = mtod(m, struct ip6_hdr *); ovbcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr)); /* Fake link-local scope-class addresses */ if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src)) oip6->ip6_src.s6_addr16[1] = 0; if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst)) oip6->ip6_dst.s6_addr16[1] = 0; /* construct new IPv6 header. see RFC 2401 5.1.2.2 */ /* ECN consideration. */ ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow); if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr)) ip6->ip6_plen = htons(plen); else { /* ip6->ip6_plen will be updated in ip6_output() */ } ip6->ip6_nxt = IPPROTO_IPV6; sav->sah->saidx.src.sin6.sin6_addr = ip6->ip6_src; sav->sah->saidx.dst.sin6.sin6_addr = ip6->ip6_dst; ip6->ip6_hlim = IPV6_DEFHLIM; /* XXX Should ip6_src be updated later ? */ return 0; } /* * IPsec output logic for IPv6, tunnel mode. */ int ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags) { struct ip6_hdr *ip6; struct ipsecrequest *isr; struct secasindex saidx; int error; struct sockaddr_in6* dst6; struct mbuf *m; KASSERT(state != NULL, ("ipsec6_output: null state")); KASSERT(state->m != NULL, ("ipsec6_output: null m")); KASSERT(sp != NULL, ("ipsec6_output: null sp")); KEYDEBUG(KEYDEBUG_IPSEC_DATA, printf("ipsec6_output_tunnel: applyed SP\n"); kdebug_secpolicy(sp)); m = state->m; /* * transport mode ipsec (before the 1st tunnel mode) is already * processed by ipsec6_output_trans(). */ for (isr = sp->req; isr; isr = isr->next) { if (isr->saidx.mode == IPSEC_MODE_TUNNEL) break; } isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error); if (isr == NULL) goto bad; /* * There may be the case that SA status will be changed when * we are refering to one. So calling splsoftnet(). */ if (isr->saidx.mode == IPSEC_MODE_TUNNEL) { /* * build IPsec tunnel. */ /* XXX should be processed with other familiy */ if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) { ipseclog((LOG_ERR, "ipsec6_output_tunnel: " "family mismatched between inner and outer, spi=%u\n", ntohl(isr->sav->spi))); newipsecstat.ips_out_inval++; error = EAFNOSUPPORT; goto bad; } m = ipsec6_splithdr(m); if (!m) { newipsecstat.ips_out_nomem++; error = ENOMEM; goto bad; } error = ipsec6_encapsulate(m, isr->sav); if (error) { m = NULL; goto bad; } ip6 = mtod(m, struct ip6_hdr *); state->ro = &isr->sav->sah->sa_route; state->dst = (struct sockaddr *)&state->ro->ro_dst; dst6 = (struct sockaddr_in6 *)state->dst; if (state->ro->ro_rt && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0 || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) { RTFREE(state->ro->ro_rt); state->ro->ro_rt = NULL; } if (state->ro->ro_rt == 0) { bzero(dst6, sizeof(*dst6)); dst6->sin6_family = AF_INET6; dst6->sin6_len = sizeof(*dst6); dst6->sin6_addr = ip6->ip6_dst; rtalloc(state->ro); } if (state->ro->ro_rt == 0) { ip6stat.ip6s_noroute++; newipsecstat.ips_out_noroute++; error = EHOSTUNREACH; goto bad; } /* adjust state->dst if tunnel endpoint is offlink */ if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) { state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway; dst6 = (struct sockaddr_in6 *)state->dst; } } m = ipsec6_splithdr(m); if (!m) { newipsecstat.ips_out_nomem++; error = ENOMEM; goto bad; } ip6 = mtod(m, struct ip6_hdr *); return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL, sizeof (struct ip6_hdr), offsetof(struct ip6_hdr, ip6_nxt)); bad: if (m) m_freem(m); state->m = NULL; return error; } #endif /*INET6*/