diff options
Diffstat (limited to 'sys/netinet/ip_ipsec.c')
| -rw-r--r-- | sys/netinet/ip_ipsec.c | 394 |
1 files changed, 394 insertions, 0 deletions
diff --git a/sys/netinet/ip_ipsec.c b/sys/netinet/ip_ipsec.c new file mode 100644 index 0000000..526a6de --- /dev/null +++ b/sys/netinet/ip_ipsec.c @@ -0,0 +1,394 @@ +/*- + * 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. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "opt_ipsec.h" +#include "opt_sctp.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/errno.h> +#include <sys/kernel.h> +#include <sys/malloc.h> +#include <sys/mbuf.h> +#include <sys/protosw.h> +#include <sys/socket.h> +#include <sys/socketvar.h> +#include <sys/sysctl.h> + +#include <net/if.h> +#include <net/route.h> +#include <net/vnet.h> + +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/in_var.h> +#include <netinet/ip.h> +#include <netinet/in_pcb.h> +#include <netinet/ip_var.h> +#include <netinet/ip_options.h> +#include <netinet/ip_ipsec.h> +#ifdef SCTP +#include <netinet/sctp_crc32.h> +#endif + +#include <machine/in_cksum.h> + +#ifdef IPSEC +#include <netipsec/ipsec.h> +#include <netipsec/xform.h> +#include <netipsec/key.h> +#endif /*IPSEC*/ + +extern struct protosw inetsw[]; + +#ifdef IPSEC +#ifdef IPSEC_FILTERTUNNEL +static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 1; +#else +static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 0; +#endif +#define V_ip4_ipsec_filtertunnel VNET(ip4_ipsec_filtertunnel) + +SYSCTL_DECL(_net_inet_ipsec); +SYSCTL_VNET_INT(_net_inet_ipsec, OID_AUTO, filtertunnel, + CTLFLAG_RW, &VNET_NAME(ip4_ipsec_filtertunnel), 0, + "If set filter packets from an IPsec tunnel."); +#endif /* IPSEC */ + +/* + * 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_filtertunnel(struct mbuf *m) +{ +#ifdef IPSEC + + /* + * Bypass packet filtering for packets previously handled by IPsec. + */ + if (!V_ip4_ipsec_filtertunnel && + 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 IPSEC + struct m_tag *mtag; + struct tdb_ident *tdbi; + struct secpolicy *sp; + int error; + + mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); + 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 */ + /*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); + if (error) { + IPSTAT_INC(ips_cantforward); + return 1; + } +#endif /* 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) +{ +#ifdef IPSEC + struct ip *ip = mtod(m, struct ip *); + struct m_tag *mtag; + struct tdb_ident *tdbi; + struct secpolicy *sp; + int error; + /* + * 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); + 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; + } + if (error) + return 1; + } +#endif /* 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) +{ + /* + * 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; + sp = ipsec_getpolicybyaddr(m, + IPSEC_DIR_OUTBOUND, + IP_FORWARDING, + &ipsecerror); + if (sp != NULL) { + /* count IPsec header size */ + ipsechdr = ipsec_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->route_cache.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; + } + } + KEY_FREESP(&sp); + } + return mtu; +} + +/* + * + * Called from ip_output(). + * 1 = drop packet, 0 = continue processing packet, + * -1 = packet was reinjected and stop processing packet + */ +int +ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error) +{ +#ifdef IPSEC + struct secpolicy *sp = NULL; + struct tdb_ident *tdbi; + struct m_tag *mtag; + /* + * 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); + 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; + 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; + } +#ifdef SCTP + if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) { + struct ip *ip = mtod(*m, struct ip *); + + sctp_delayed_cksum(*m, (uint32_t)(ip->ip_hl << 2)); + (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP; + } +#endif + + /* NB: callee frees mbuf */ + *error = ipsec4_process_packet(*m, sp->req, *flags, 0); + if (*error == EJUSTRETURN) { + /* + * We had a SP with a level of 'use' and no SA. We + * will just continue to process the packet without + * IPsec processing and return without error. + */ + *error = 0; + goto done; + } + /* + * 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; + goto reinjected; + } else { /* sp == NULL */ + + 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. */ + } + } +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 /* IPSEC */ + return 0; +} |
