From 2013a6774517ce67b21d1f06a6d71bc34f75ca7e Mon Sep 17 00:00:00 2001 From: andre Date: Wed, 1 Feb 2006 13:55:03 +0000 Subject: Move the IPSEC related code blocks to their own file to unclutter and signifincantly improve the readability of ip_input() and ip_output() again. The resulting IPSEC hooks in ip_input() and ip_output() may be used later on for making IPSEC loadable. This move is mostly mechanical and should preserve current IPSEC behaviour as-is. Nothing shall prevent improvements in the way IPSEC interacts with the IPv4 stack. Discussed with: bz, gnn, rwatson; (earlier version) --- sys/netinet/ip_ipsec.c | 579 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 579 insertions(+) create mode 100644 sys/netinet/ip_ipsec.c (limited to 'sys/netinet/ip_ipsec.c') diff --git a/sys/netinet/ip_ipsec.c b/sys/netinet/ip_ipsec.c new file mode 100644 index 0000000..eee144f --- /dev/null +++ b/sys/netinet/ip_ipsec.c @@ -0,0 +1,579 @@ +/*- + * 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 + +#include + +#ifdef IPSEC +#include +#include +#ifdef IPSEC_DEBUG +#include +#else +#define KEYDEBUG(lev,arg) +#endif +#endif /*IPSEC*/ + +#ifdef FAST_IPSEC +#include +#include +#include +#endif /*FAST_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_filtergif(struct mbuf *m) +{ +#if defined(IPSEC) && !defined(IPSEC_FILTERGIF) + /* + * Bypass packet filtering for packets from a tunnel (gif). + */ + if (ipsec_getnhist(m)) + return 1; +#endif +#if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) + /* + * Bypass packet filtering for packets from a tunnel (gif). + */ + 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 FAST_IPSEC + struct m_tag *mtag; + struct tdb_ident *tdbi; + struct secpolicy *sp; + int s, error; +#endif /* FAST_IPSEC */ +#ifdef IPSEC + /* + * Enforce inbound IPsec SPD. + */ + if (ipsec4_in_reject(m, NULL)) { + ipsecstat.in_polvio++; + return 1; + } +#endif /* IPSEC */ +#ifdef FAST_IPSEC + 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 /* FAST_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 FAST_IPSEC + struct m_tag *mtag; + struct tdb_ident *tdbi; + struct secpolicy *sp; + int s, error; +#endif /* FAST_IPSEC */ +#ifdef IPSEC + /* + * 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 && + ipsec4_in_reject(m, NULL)) { + ipsecstat.in_polvio++; + return 1; + } +#endif +#ifdef FAST_IPSEC + /* + * 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 /* FAST_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; +#ifdef IPSEC + sp = ipsec4_getpolicybyaddr(m, + IPSEC_DIR_OUTBOUND, + IP_FORWARDING, + &ipsecerror); +#else /* FAST_IPSEC */ + sp = ipsec_getpolicybyaddr(m, + IPSEC_DIR_OUTBOUND, + IP_FORWARDING, + &ipsecerror); +#endif + 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; + } + } +#ifdef IPSEC + key_freesp(sp); +#else /* FAST_IPSEC */ + KEY_FREESP(&sp); +#endif + } + return mtu; +} + +/* + * + * Called from ip_output(). + * 1 = drop packet, 0 = continue processing packet, + * -1 = packet was reinjected and stop processing packet (FAST_IPSEC only) + */ +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) +{ + struct secpolicy *sp = NULL; + struct ip *ip = mtod(*m, struct ip *); +#ifdef IPSEC + struct ipsec_output_state state; +#endif +#ifdef FAST_IPSEC + struct tdb_ident *tdbi; + struct m_tag *mtag; + int s; +#endif /* FAST_IPSEC */ +#ifdef IPSEC + /* get SP for this packet */ + if (inp == NULL) + sp = ipsec4_getpolicybyaddr(*m, IPSEC_DIR_OUTBOUND, + *flags, error); + else + sp = ipsec4_getpolicybypcb(*m, IPSEC_DIR_OUTBOUND, inp, error); + + if (sp == NULL) { + ipsecstat.out_inval++; + goto bad; + } + + /* check policy */ + switch (sp->policy) { + case IPSEC_POLICY_DISCARD: + /* + * This packet is just discarded. + */ + ipsecstat.out_polvio++; + goto bad; + + case IPSEC_POLICY_BYPASS: + case IPSEC_POLICY_NONE: + case IPSEC_POLICY_TCP: + /* no need to do IPsec. */ + goto done; + + case IPSEC_POLICY_IPSEC: + if (sp->req == NULL) { + /* acquire a policy */ + *error = key_spdacquire(sp); + goto bad; + } + break; + + case IPSEC_POLICY_ENTRUST: + default: + printf("%s: Invalid policy found. %d\n", __func__, sp->policy); + } + + bzero(&state, sizeof(state)); + state.m = *m; + if (*flags & IP_ROUTETOIF) { + state.ro = iproute; + bzero(iproute, sizeof(iproute)); + } else + state.ro = *ro; + state.dst = (struct sockaddr *)(*dst); + + ip->ip_sum = 0; + + /* + * XXX + * delayed checksums are not currently compatible with IPsec + */ + 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); + + *error = ipsec4_output(&state, sp, *flags); + + *m = state.m; + if (*flags & IP_ROUTETOIF) { + /* + * if we have tunnel mode SA, we may need to ignore + * IP_ROUTETOIF. + */ + if (state.ro != iproute || state.ro->ro_rt != NULL) { + *flags &= ~IP_ROUTETOIF; + *ro = state.ro; + } + } else + *ro = state.ro; + *dst = (struct sockaddr_in *)state.dst; + if (*error != 0) { + /* mbuf is already reclaimed in ipsec4_output. */ + *m = NULL; + switch (*error) { + case EHOSTUNREACH: + case ENETUNREACH: + case EMSGSIZE: + case ENOBUFS: + case ENOMEM: + break; + default: + printf("ip4_output (ipsec): error code %d\n", *error); + /*fall through*/ + case ENOENT: + /* don't show these error codes to the user */ + *error = 0; + break; + } + goto bad; + } + + /* be sure to update variables that are affected by ipsec4_output() */ + if ((*ro)->ro_rt == NULL) { + if ((*flags & IP_ROUTETOIF) == 0) { + printf("ip_output: " + "can't update route after IPsec processing\n"); + *error = EHOSTUNREACH; /*XXX*/ + goto bad; + } + } else { + if (state.encap) { + *ia = ifatoia((*ro)->ro_rt->rt_ifa); + *ifp = (*ro)->ro_rt->rt_ifp; + } + } + + /* make it flipped, again. */ + ip->ip_len = ntohs(ip->ip_len); + ip->ip_off = ntohs(ip->ip_off); + +done: + if (sp != NULL) { + KEYDEBUG(KEYDEBUG_IPSEC_STAMP, + printf("DP ip_output call free SP:%p\n", sp)); + key_freesp(sp); + } + return 0; +bad: + if (sp != NULL) { + KEYDEBUG(KEYDEBUG_IPSEC_STAMP, + printf("DP ip_output call free SP:%p\n", sp)); + key_freesp(sp); + } + return 1; +#endif /*IPSEC*/ +#ifdef FAST_IPSEC + /* + * 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 /* FAST_IPSEC */ + return 0; +} + -- cgit v1.1