diff options
Diffstat (limited to 'sys/netipsec/xform_ipip.c')
-rw-r--r-- | sys/netipsec/xform_ipip.c | 688 |
1 files changed, 688 insertions, 0 deletions
diff --git a/sys/netipsec/xform_ipip.c b/sys/netipsec/xform_ipip.c new file mode 100644 index 0000000..8191009 --- /dev/null +++ b/sys/netipsec/xform_ipip.c @@ -0,0 +1,688 @@ +/* $FreeBSD$ */ +/* $OpenBSD: ip_ipip.c,v 1.25 2002/06/10 18:04:55 itojun 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). + * + * The original version of 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. + */ + +/* + * IP-inside-IP processing + */ +#include "opt_inet.h" +#include "opt_inet6.h" +#include "opt_enc.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/mbuf.h> +#include <sys/socket.h> +#include <sys/kernel.h> +#include <sys/protosw.h> +#include <sys/sysctl.h> + +#include <net/if.h> +#include <net/route.h> +#include <net/netisr.h> + +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/in_var.h> +#include <netinet/ip.h> +#include <netinet/ip_ecn.h> +#include <netinet/ip_var.h> +#include <netinet/ip_encap.h> + +#include <netipsec/ipsec.h> +#include <netipsec/xform.h> + +#include <netipsec/ipip_var.h> + +#ifdef MROUTING +#include <netinet/ip_mroute.h> +#endif + +#ifdef INET6 +#include <netinet/ip6.h> +#include <netipsec/ipsec6.h> +#include <netinet6/ip6_ecn.h> +#include <netinet6/in6_var.h> +#include <netinet6/ip6protosw.h> +#endif + +#include <netipsec/key.h> +#include <netipsec/key_debug.h> + +#include <machine/stdarg.h> + +/* + * We can control the acceptance of IP4 packets by altering the sysctl + * net.inet.ipip.allow value. Zero means drop them, all else is acceptance. + */ +int ipip_allow = 0; +struct ipipstat ipipstat; + +SYSCTL_DECL(_net_inet_ipip); +SYSCTL_INT(_net_inet_ipip, OID_AUTO, + ipip_allow, CTLFLAG_RW, &ipip_allow, 0, ""); +SYSCTL_STRUCT(_net_inet_ipip, IPSECCTL_STATS, + stats, CTLFLAG_RD, &ipipstat, ipipstat, ""); + +/* XXX IPCOMP */ +#define M_IPSEC (M_AUTHIPHDR|M_AUTHIPDGM|M_DECRYPTED) + +static void _ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp); + +#ifdef INET6 +/* + * Really only a wrapper for ipip_input(), for use with IPv6. + */ +int +ip4_input6(struct mbuf **m, int *offp, int proto) +{ +#if 0 + /* If we do not accept IP-in-IP explicitly, drop. */ + if (!ipip_allow && ((*m)->m_flags & M_IPSEC) == 0) { + DPRINTF(("%s: dropped due to policy\n", __func__)); + ipipstat.ipips_pdrops++; + m_freem(*m); + return IPPROTO_DONE; + } +#endif + _ipip_input(*m, *offp, NULL); + return IPPROTO_DONE; +} +#endif /* INET6 */ + +#ifdef INET +/* + * Really only a wrapper for ipip_input(), for use with IPv4. + */ +void +ip4_input(struct mbuf *m, int off) +{ +#if 0 + /* If we do not accept IP-in-IP explicitly, drop. */ + if (!ipip_allow && (m->m_flags & M_IPSEC) == 0) { + DPRINTF(("%s: dropped due to policy\n", __func__)); + ipipstat.ipips_pdrops++; + m_freem(m); + return; + } +#endif + _ipip_input(m, off, NULL); +} +#endif /* INET */ + +/* + * ipip_input gets called when we receive an IP{46} encapsulated packet, + * either because we got it at a real interface, or because AH or ESP + * were being used in tunnel mode (in which case the rcvif element will + * contain the address of the encX interface associated with the tunnel. + */ + +static void +_ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp) +{ + register struct sockaddr_in *sin; + register struct ifnet *ifp; + register struct ifaddr *ifa; + struct ip *ipo; +#ifdef INET6 + register struct sockaddr_in6 *sin6; + struct ip6_hdr *ip6 = NULL; + u_int8_t itos; +#endif + u_int8_t nxt; + int isr; + u_int8_t otos; + u_int8_t v; + int hlen; + + ipipstat.ipips_ipackets++; + + m_copydata(m, 0, 1, &v); + + switch (v >> 4) { +#ifdef INET + case 4: + hlen = sizeof(struct ip); + break; +#endif /* INET */ +#ifdef INET6 + case 6: + hlen = sizeof(struct ip6_hdr); + break; +#endif + default: + ipipstat.ipips_family++; + m_freem(m); + return /* EAFNOSUPPORT */; + } + + /* Bring the IP header in the first mbuf, if not there already */ + if (m->m_len < hlen) { + if ((m = m_pullup(m, hlen)) == NULL) { + DPRINTF(("%s: m_pullup (1) failed\n", __func__)); + ipipstat.ipips_hdrops++; + return; + } + } + + ipo = mtod(m, struct ip *); + +#ifdef MROUTING + if (ipo->ip_v == IPVERSION && ipo->ip_p == IPPROTO_IPV4) { + if (IN_MULTICAST(((struct ip *)((char *) ipo + iphlen))->ip_dst.s_addr)) { + ipip_mroute_input (m, iphlen); + return; + } + } +#endif /* MROUTING */ + + /* Keep outer ecn field. */ + switch (v >> 4) { +#ifdef INET + case 4: + otos = ipo->ip_tos; + break; +#endif /* INET */ +#ifdef INET6 + case 6: + otos = (ntohl(mtod(m, struct ip6_hdr *)->ip6_flow) >> 20) & 0xff; + break; +#endif + default: + panic("ipip_input: unknown ip version %u (outer)", v>>4); + } + + /* Remove outer IP header */ + m_adj(m, iphlen); + + /* Sanity check */ + if (m->m_pkthdr.len < sizeof(struct ip)) { + ipipstat.ipips_hdrops++; + m_freem(m); + return; + } + + m_copydata(m, 0, 1, &v); + + switch (v >> 4) { +#ifdef INET + case 4: + hlen = sizeof(struct ip); + break; +#endif /* INET */ + +#ifdef INET6 + case 6: + hlen = sizeof(struct ip6_hdr); + break; +#endif + default: + ipipstat.ipips_family++; + m_freem(m); + return; /* EAFNOSUPPORT */ + } + + /* + * Bring the inner IP header in the first mbuf, if not there already. + */ + if (m->m_len < hlen) { + if ((m = m_pullup(m, hlen)) == NULL) { + DPRINTF(("%s: m_pullup (2) failed\n", __func__)); + ipipstat.ipips_hdrops++; + return; + } + } + + /* + * RFC 1853 specifies that the inner TTL should not be touched on + * decapsulation. There's no reason this comment should be here, but + * this is as good as any a position. + */ + + /* Some sanity checks in the inner IP header */ + switch (v >> 4) { +#ifdef INET + case 4: + ipo = mtod(m, struct ip *); + nxt = ipo->ip_p; + ip_ecn_egress(ip4_ipsec_ecn, &otos, &ipo->ip_tos); + break; +#endif /* INET */ +#ifdef INET6 + case 6: + ip6 = (struct ip6_hdr *) ipo; + nxt = ip6->ip6_nxt; + itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; + ip_ecn_egress(ip6_ipsec_ecn, &otos, &itos); + ip6->ip6_flow &= ~htonl(0xff << 20); + ip6->ip6_flow |= htonl((u_int32_t) itos << 20); + break; +#endif + default: + panic("ipip_input: unknown ip version %u (inner)", v>>4); + } + + /* Check for local address spoofing. */ + if ((m->m_pkthdr.rcvif == NULL || + !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) && + ipip_allow != 2) { + IFNET_RLOCK(); + TAILQ_FOREACH(ifp, &ifnet, if_link) { + TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { +#ifdef INET + if (ipo) { + if (ifa->ifa_addr->sa_family != + AF_INET) + continue; + + sin = (struct sockaddr_in *) ifa->ifa_addr; + + if (sin->sin_addr.s_addr == + ipo->ip_src.s_addr) { + ipipstat.ipips_spoof++; + m_freem(m); + IFNET_RUNLOCK(); + return; + } + } +#endif /* INET */ + +#ifdef INET6 + if (ip6) { + if (ifa->ifa_addr->sa_family != + AF_INET6) + continue; + + sin6 = (struct sockaddr_in6 *) ifa->ifa_addr; + + if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &ip6->ip6_src)) { + ipipstat.ipips_spoof++; + m_freem(m); + IFNET_RUNLOCK(); + return; + } + + } +#endif /* INET6 */ + } + } + IFNET_RUNLOCK(); + } + + /* Statistics */ + ipipstat.ipips_ibytes += m->m_pkthdr.len - iphlen; + +#ifdef DEV_ENC + /* pass the mbuf to enc0 for packet filtering */ + if (ipsec_filter(&m, 1) != 0) + return; +#endif + + /* + * Interface pointer stays the same; if no IPsec processing has + * been done (or will be done), this will point to a normal + * interface. Otherwise, it'll point to an enc interface, which + * will allow a packet filter to distinguish between secure and + * untrusted packets. + */ + + switch (v >> 4) { +#ifdef INET + case 4: + isr = NETISR_IP; + break; +#endif +#ifdef INET6 + case 6: + isr = NETISR_IPV6; + break; +#endif + default: + panic("%s: bogus ip version %u", __func__, v>>4); + } + + if (netisr_queue(isr, m)) { /* (0) on success. */ + ipipstat.ipips_qfull++; + DPRINTF(("%s: packet dropped because of full queue\n", + __func__)); + } +} + +int +ipip_output( + struct mbuf *m, + struct ipsecrequest *isr, + struct mbuf **mp, + int skip, + int protoff +) +{ + struct secasvar *sav; + u_int8_t tp, otos; + struct secasindex *saidx; + int error; +#ifdef INET + u_int8_t itos; + struct ip *ipo; +#endif /* INET */ +#ifdef INET6 + struct ip6_hdr *ip6, *ip6o; +#endif /* INET6 */ + + IPSEC_SPLASSERT_SOFTNET(__func__); + + sav = isr->sav; + IPSEC_ASSERT(sav != NULL, ("null SA")); + IPSEC_ASSERT(sav->sah != NULL, ("null SAH")); + + /* XXX Deal with empty TDB source/destination addresses. */ + + m_copydata(m, 0, 1, &tp); + tp = (tp >> 4) & 0xff; /* Get the IP version number. */ + + saidx = &sav->sah->saidx; + switch (saidx->dst.sa.sa_family) { +#ifdef INET + case AF_INET: + if (saidx->src.sa.sa_family != AF_INET || + saidx->src.sin.sin_addr.s_addr == INADDR_ANY || + saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) { + DPRINTF(("%s: unspecified tunnel endpoint " + "address in SA %s/%08lx\n", __func__, + ipsec_address(&saidx->dst), + (u_long) ntohl(sav->spi))); + ipipstat.ipips_unspec++; + error = EINVAL; + goto bad; + } + + M_PREPEND(m, sizeof(struct ip), M_DONTWAIT); + if (m == 0) { + DPRINTF(("%s: M_PREPEND failed\n", __func__)); + ipipstat.ipips_hdrops++; + error = ENOBUFS; + goto bad; + } + + ipo = mtod(m, struct ip *); + + ipo->ip_v = IPVERSION; + ipo->ip_hl = 5; + ipo->ip_len = htons(m->m_pkthdr.len); + ipo->ip_ttl = ip_defttl; + ipo->ip_sum = 0; + ipo->ip_src = saidx->src.sin.sin_addr; + ipo->ip_dst = saidx->dst.sin.sin_addr; + + ipo->ip_id = ip_newid(); + + /* If the inner protocol is IP... */ + if (tp == IPVERSION) { + /* Save ECN notification */ + m_copydata(m, sizeof(struct ip) + + offsetof(struct ip, ip_tos), + sizeof(u_int8_t), (caddr_t) &itos); + + ipo->ip_p = IPPROTO_IPIP; + + /* + * We should be keeping tunnel soft-state and + * send back ICMPs if needed. + */ + m_copydata(m, sizeof(struct ip) + + offsetof(struct ip, ip_off), + sizeof(u_int16_t), (caddr_t) &ipo->ip_off); + ipo->ip_off = ntohs(ipo->ip_off); + ipo->ip_off &= ~(IP_DF | IP_MF | IP_OFFMASK); + ipo->ip_off = htons(ipo->ip_off); + } +#ifdef INET6 + else if (tp == (IPV6_VERSION >> 4)) { + u_int32_t itos32; + + /* Save ECN notification. */ + m_copydata(m, sizeof(struct ip) + + offsetof(struct ip6_hdr, ip6_flow), + sizeof(u_int32_t), (caddr_t) &itos32); + itos = ntohl(itos32) >> 20; + ipo->ip_p = IPPROTO_IPV6; + ipo->ip_off = 0; + } +#endif /* INET6 */ + else { + goto nofamily; + } + + otos = 0; + ip_ecn_ingress(ECN_ALLOWED, &otos, &itos); + ipo->ip_tos = otos; + break; +#endif /* INET */ + +#ifdef INET6 + case AF_INET6: + if (IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr) || + saidx->src.sa.sa_family != AF_INET6 || + IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr)) { + DPRINTF(("%s: unspecified tunnel endpoint " + "address in SA %s/%08lx\n", __func__, + ipsec_address(&saidx->dst), + (u_long) ntohl(sav->spi))); + ipipstat.ipips_unspec++; + error = ENOBUFS; + goto bad; + } + + /* scoped address handling */ + ip6 = mtod(m, struct ip6_hdr *); + if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) + ip6->ip6_src.s6_addr16[1] = 0; + if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) + ip6->ip6_dst.s6_addr16[1] = 0; + + M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT); + if (m == 0) { + DPRINTF(("%s: M_PREPEND failed\n", __func__)); + ipipstat.ipips_hdrops++; + error = ENOBUFS; + goto bad; + } + + /* Initialize IPv6 header */ + ip6o = mtod(m, struct ip6_hdr *); + ip6o->ip6_flow = 0; + ip6o->ip6_vfc &= ~IPV6_VERSION_MASK; + ip6o->ip6_vfc |= IPV6_VERSION; + ip6o->ip6_plen = htons(m->m_pkthdr.len); + ip6o->ip6_hlim = ip_defttl; + ip6o->ip6_dst = saidx->dst.sin6.sin6_addr; + ip6o->ip6_src = saidx->src.sin6.sin6_addr; + +#ifdef INET + if (tp == IPVERSION) { + /* Save ECN notification */ + m_copydata(m, sizeof(struct ip6_hdr) + + offsetof(struct ip, ip_tos), sizeof(u_int8_t), + (caddr_t) &itos); + + /* This is really IPVERSION. */ + ip6o->ip6_nxt = IPPROTO_IPIP; + } else +#endif /* INET */ + if (tp == (IPV6_VERSION >> 4)) { + u_int32_t itos32; + + /* Save ECN notification. */ + m_copydata(m, sizeof(struct ip6_hdr) + + offsetof(struct ip6_hdr, ip6_flow), + sizeof(u_int32_t), (caddr_t) &itos32); + itos = ntohl(itos32) >> 20; + + ip6o->ip6_nxt = IPPROTO_IPV6; + } else { + goto nofamily; + } + + otos = 0; + ip_ecn_ingress(ECN_ALLOWED, &otos, &itos); + ip6o->ip6_flow |= htonl((u_int32_t) otos << 20); + break; +#endif /* INET6 */ + + default: +nofamily: + DPRINTF(("%s: unsupported protocol family %u\n", __func__, + saidx->dst.sa.sa_family)); + ipipstat.ipips_family++; + error = EAFNOSUPPORT; /* XXX diffs from openbsd */ + goto bad; + } + + ipipstat.ipips_opackets++; + *mp = m; + +#ifdef INET + if (saidx->dst.sa.sa_family == AF_INET) { +#if 0 + if (sav->tdb_xform->xf_type == XF_IP4) + tdb->tdb_cur_bytes += + m->m_pkthdr.len - sizeof(struct ip); +#endif + ipipstat.ipips_obytes += m->m_pkthdr.len - sizeof(struct ip); + } +#endif /* INET */ + +#ifdef INET6 + if (saidx->dst.sa.sa_family == AF_INET6) { +#if 0 + if (sav->tdb_xform->xf_type == XF_IP4) + tdb->tdb_cur_bytes += + m->m_pkthdr.len - sizeof(struct ip6_hdr); +#endif + ipipstat.ipips_obytes += + m->m_pkthdr.len - sizeof(struct ip6_hdr); + } +#endif /* INET6 */ + + return 0; +bad: + if (m) + m_freem(m); + *mp = NULL; + return (error); +} + +#ifdef FAST_IPSEC +static int +ipe4_init(struct secasvar *sav, struct xformsw *xsp) +{ + sav->tdb_xform = xsp; + return 0; +} + +static int +ipe4_zeroize(struct secasvar *sav) +{ + sav->tdb_xform = NULL; + return 0; +} + +static int +ipe4_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) +{ + /* This is a rather serious mistake, so no conditional printing. */ + printf("%s: should never be called\n", __func__); + if (m) + m_freem(m); + return EOPNOTSUPP; +} + +static struct xformsw ipe4_xformsw = { + XF_IP4, 0, "IPv4 Simple Encapsulation", + ipe4_init, ipe4_zeroize, ipe4_input, ipip_output, +}; + +extern struct domain inetdomain; +static struct protosw ipe4_protosw = +{ SOCK_RAW, &inetdomain, IPPROTO_IPV4, PR_ATOMIC|PR_ADDR|PR_LASTHDR, + ip4_input, + 0, 0, rip_ctloutput, + 0, + 0, 0, 0, 0, + &rip_usrreqs +}; +#ifdef INET6 +static struct ip6protosw ipe6_protosw = +{ SOCK_RAW, &inetdomain, IPPROTO_IPV6, PR_ATOMIC|PR_ADDR|PR_LASTHDR, + ip4_input6, + 0, 0, rip_ctloutput, + 0, + 0, 0, 0, 0, + &rip_usrreqs +}; +#endif + +/* + * Check the encapsulated packet to see if we want it + */ +static int +ipe4_encapcheck(const struct mbuf *m, int off, int proto, void *arg) +{ + /* + * Only take packets coming from IPSEC tunnels; the rest + * must be handled by the gif tunnel code. Note that we + * also return a minimum priority when we want the packet + * so any explicit gif tunnels take precedence. + */ + return ((m->m_flags & M_IPSEC) != 0 ? 1 : 0); +} + +static void +ipe4_attach(void) +{ + xform_register(&ipe4_xformsw); + /* attach to encapsulation framework */ + /* XXX save return cookie for detach on module remove */ + (void) encap_attach_func(AF_INET, -1, + ipe4_encapcheck, &ipe4_protosw, NULL); +#ifdef INET6 + (void) encap_attach_func(AF_INET6, -1, + ipe4_encapcheck, (struct protosw *)&ipe6_protosw, NULL); +#endif +} +SYSINIT(ipe4_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ipe4_attach, NULL); +#endif /* FAST_IPSEC */ |