580 lines
14 KiB
C
580 lines
14 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include "opt_ipsec.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/in_pcb.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip_options.h>
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#include <netinet/ip_ipsec.h>
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#include <machine/in_cksum.h>
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#ifdef IPSEC
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#include <netinet6/ipsec.h>
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#include <netkey/key.h>
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#ifdef IPSEC_DEBUG
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#include <netkey/key_debug.h>
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#else
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#define KEYDEBUG(lev,arg)
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#endif
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#endif /*IPSEC*/
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#ifdef FAST_IPSEC
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#include <netipsec/ipsec.h>
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#include <netipsec/xform.h>
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#include <netipsec/key.h>
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#endif /*FAST_IPSEC*/
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extern struct protosw inetsw[];
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/*
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* Check if we have to jump over firewall processing for this packet.
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* Called from ip_input().
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* 1 = jump over firewall, 0 = packet goes through firewall.
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*/
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int
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ip_ipsec_filtergif(struct mbuf *m)
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{
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#if defined(IPSEC) && !defined(IPSEC_FILTERGIF)
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/*
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* Bypass packet filtering for packets from a tunnel (gif).
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*/
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if (ipsec_getnhist(m))
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return 1;
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#endif
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#if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF)
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/*
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* Bypass packet filtering for packets from a tunnel (gif).
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*/
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if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
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return 1;
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#endif
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return 0;
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}
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/*
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* Check if this packet has an active SA and needs to be dropped instead
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* of forwarded.
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* Called from ip_input().
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* 1 = drop packet, 0 = forward packet.
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*/
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int
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ip_ipsec_fwd(struct mbuf *m)
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{
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#ifdef FAST_IPSEC
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struct m_tag *mtag;
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struct tdb_ident *tdbi;
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struct secpolicy *sp;
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int s, error;
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#endif /* FAST_IPSEC */
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#ifdef IPSEC
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/*
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* Enforce inbound IPsec SPD.
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*/
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if (ipsec4_in_reject(m, NULL)) {
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ipsecstat.in_polvio++;
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return 1;
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}
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#endif /* IPSEC */
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#ifdef FAST_IPSEC
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mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
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s = splnet();
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if (mtag != NULL) {
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tdbi = (struct tdb_ident *)(mtag + 1);
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sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
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} else {
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sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
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IP_FORWARDING, &error);
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}
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if (sp == NULL) { /* NB: can happen if error */
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splx(s);
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/*XXX error stat???*/
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DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
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return 1;
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}
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/*
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* Check security policy against packet attributes.
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*/
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error = ipsec_in_reject(sp, m);
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KEY_FREESP(&sp);
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splx(s);
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if (error) {
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ipstat.ips_cantforward++;
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return 1;
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}
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#endif /* FAST_IPSEC */
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return 0;
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}
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/*
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* Check if protocol type doesn't have a further header and do IPSEC
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* decryption or reject right now. Protocols with further headers get
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* their IPSEC treatment within the protocol specific processing.
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* Called from ip_input().
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* 1 = drop packet, 0 = continue processing packet.
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*/
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int
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ip_ipsec_input(struct mbuf *m)
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{
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struct ip *ip = mtod(m, struct ip *);
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#ifdef FAST_IPSEC
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struct m_tag *mtag;
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struct tdb_ident *tdbi;
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struct secpolicy *sp;
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int s, error;
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#endif /* FAST_IPSEC */
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#ifdef IPSEC
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/*
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* enforce IPsec policy checking if we are seeing last header.
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* note that we do not visit this with protocols with pcb layer
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* code - like udp/tcp/raw ip.
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*/
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if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 &&
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ipsec4_in_reject(m, NULL)) {
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ipsecstat.in_polvio++;
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return 1;
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}
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#endif
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#ifdef FAST_IPSEC
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/*
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* enforce IPsec policy checking if we are seeing last header.
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* note that we do not visit this with protocols with pcb layer
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* code - like udp/tcp/raw ip.
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*/
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if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
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/*
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* Check if the packet has already had IPsec processing
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* done. If so, then just pass it along. This tag gets
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* set during AH, ESP, etc. input handling, before the
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* packet is returned to the ip input queue for delivery.
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*/
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mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
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s = splnet();
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if (mtag != NULL) {
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tdbi = (struct tdb_ident *)(mtag + 1);
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sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
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} else {
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sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
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IP_FORWARDING, &error);
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}
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if (sp != NULL) {
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/*
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* Check security policy against packet attributes.
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*/
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error = ipsec_in_reject(sp, m);
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KEY_FREESP(&sp);
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} else {
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/* XXX error stat??? */
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error = EINVAL;
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DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
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return 1;
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}
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splx(s);
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if (error)
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return 1;
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}
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#endif /* FAST_IPSEC */
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return 0;
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}
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/*
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* Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
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* Called from ip_forward().
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* Returns MTU suggestion for ICMP needfrag reply.
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*/
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int
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ip_ipsec_mtu(struct mbuf *m)
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{
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int mtu = 0;
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/*
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* If the packet is routed over IPsec tunnel, tell the
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* originator the tunnel MTU.
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* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
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* XXX quickhack!!!
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*/
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struct secpolicy *sp = NULL;
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int ipsecerror;
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int ipsechdr;
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struct route *ro;
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#ifdef IPSEC
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sp = ipsec4_getpolicybyaddr(m,
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IPSEC_DIR_OUTBOUND,
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IP_FORWARDING,
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&ipsecerror);
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#else /* FAST_IPSEC */
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sp = ipsec_getpolicybyaddr(m,
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IPSEC_DIR_OUTBOUND,
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IP_FORWARDING,
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&ipsecerror);
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#endif
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if (sp != NULL) {
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/* count IPsec header size */
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ipsechdr = ipsec4_hdrsiz(m,
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IPSEC_DIR_OUTBOUND,
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NULL);
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/*
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* find the correct route for outer IPv4
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* header, compute tunnel MTU.
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*/
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if (sp->req != NULL &&
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sp->req->sav != NULL &&
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sp->req->sav->sah != NULL) {
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ro = &sp->req->sav->sah->sa_route;
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if (ro->ro_rt && ro->ro_rt->rt_ifp) {
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mtu =
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ro->ro_rt->rt_rmx.rmx_mtu ?
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ro->ro_rt->rt_rmx.rmx_mtu :
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ro->ro_rt->rt_ifp->if_mtu;
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mtu -= ipsechdr;
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}
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}
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#ifdef IPSEC
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key_freesp(sp);
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#else /* FAST_IPSEC */
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KEY_FREESP(&sp);
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#endif
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}
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return mtu;
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}
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/*
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*
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* Called from ip_output().
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* 1 = drop packet, 0 = continue processing packet,
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* -1 = packet was reinjected and stop processing packet (FAST_IPSEC only)
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*/
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int
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ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
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struct route **ro, struct route *iproute, struct sockaddr_in **dst,
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struct in_ifaddr **ia, struct ifnet **ifp)
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{
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struct secpolicy *sp = NULL;
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struct ip *ip = mtod(*m, struct ip *);
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#ifdef IPSEC
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struct ipsec_output_state state;
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#endif
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#ifdef FAST_IPSEC
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struct tdb_ident *tdbi;
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struct m_tag *mtag;
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int s;
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#endif /* FAST_IPSEC */
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#ifdef IPSEC
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/* get SP for this packet */
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if (inp == NULL)
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sp = ipsec4_getpolicybyaddr(*m, IPSEC_DIR_OUTBOUND,
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*flags, error);
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else
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sp = ipsec4_getpolicybypcb(*m, IPSEC_DIR_OUTBOUND, inp, error);
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if (sp == NULL) {
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ipsecstat.out_inval++;
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goto bad;
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}
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/* check policy */
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switch (sp->policy) {
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case IPSEC_POLICY_DISCARD:
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/*
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* This packet is just discarded.
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*/
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ipsecstat.out_polvio++;
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goto bad;
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case IPSEC_POLICY_BYPASS:
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case IPSEC_POLICY_NONE:
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case IPSEC_POLICY_TCP:
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/* no need to do IPsec. */
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goto done;
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case IPSEC_POLICY_IPSEC:
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if (sp->req == NULL) {
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/* acquire a policy */
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*error = key_spdacquire(sp);
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goto bad;
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}
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break;
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case IPSEC_POLICY_ENTRUST:
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default:
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printf("%s: Invalid policy found. %d\n", __func__, sp->policy);
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}
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bzero(&state, sizeof(state));
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state.m = *m;
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if (*flags & IP_ROUTETOIF) {
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state.ro = iproute;
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bzero(iproute, sizeof(iproute));
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} else
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state.ro = *ro;
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state.dst = (struct sockaddr *)(*dst);
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ip->ip_sum = 0;
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/*
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* XXX
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* delayed checksums are not currently compatible with IPsec
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*/
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if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
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in_delayed_cksum(*m);
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(*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
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}
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ip->ip_len = htons(ip->ip_len);
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ip->ip_off = htons(ip->ip_off);
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*error = ipsec4_output(&state, sp, *flags);
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*m = state.m;
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if (*flags & IP_ROUTETOIF) {
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/*
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* if we have tunnel mode SA, we may need to ignore
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* IP_ROUTETOIF.
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*/
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if (state.ro != iproute || state.ro->ro_rt != NULL) {
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*flags &= ~IP_ROUTETOIF;
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*ro = state.ro;
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}
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} else
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*ro = state.ro;
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*dst = (struct sockaddr_in *)state.dst;
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if (*error != 0) {
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/* mbuf is already reclaimed in ipsec4_output. */
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*m = NULL;
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switch (*error) {
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case EHOSTUNREACH:
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case ENETUNREACH:
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case EMSGSIZE:
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case ENOBUFS:
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case ENOMEM:
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break;
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default:
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printf("ip4_output (ipsec): error code %d\n", *error);
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/*fall through*/
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case ENOENT:
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/* don't show these error codes to the user */
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*error = 0;
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break;
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}
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goto bad;
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}
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/* be sure to update variables that are affected by ipsec4_output() */
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if ((*ro)->ro_rt == NULL) {
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if ((*flags & IP_ROUTETOIF) == 0) {
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printf("ip_output: "
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"can't update route after IPsec processing\n");
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*error = EHOSTUNREACH; /*XXX*/
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goto bad;
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}
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} else {
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if (state.encap) {
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*ia = ifatoia((*ro)->ro_rt->rt_ifa);
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*ifp = (*ro)->ro_rt->rt_ifp;
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}
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}
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ip = mtod(*m, struct ip *);
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/* make it flipped, again. */
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ip->ip_len = ntohs(ip->ip_len);
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ip->ip_off = ntohs(ip->ip_off);
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done:
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if (sp != NULL) {
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KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
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printf("DP ip_output call free SP:%p\n", sp));
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key_freesp(sp);
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}
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return 0;
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bad:
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if (sp != NULL) {
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KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
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printf("DP ip_output call free SP:%p\n", sp));
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key_freesp(sp);
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}
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return 1;
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#endif /*IPSEC*/
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#ifdef FAST_IPSEC
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/*
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* Check the security policy (SP) for the packet and, if
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* required, do IPsec-related processing. There are two
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* cases here; the first time a packet is sent through
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* it will be untagged and handled by ipsec4_checkpolicy.
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* If the packet is resubmitted to ip_output (e.g. after
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* AH, ESP, etc. processing), there will be a tag to bypass
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* the lookup and related policy checking.
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*/
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mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
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s = splnet();
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if (mtag != NULL) {
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tdbi = (struct tdb_ident *)(mtag + 1);
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sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
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if (sp == NULL)
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*error = -EINVAL; /* force silent drop */
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m_tag_delete(*m, mtag);
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} else {
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sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
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error, inp);
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}
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/*
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* There are four return cases:
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* sp != NULL apply IPsec policy
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* sp == NULL, error == 0 no IPsec handling needed
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* sp == NULL, error == -EINVAL discard packet w/o error
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* sp == NULL, error != 0 discard packet, report error
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*/
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if (sp != NULL) {
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/* Loop detection, check if ipsec processing already done */
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KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
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for (mtag = m_tag_first(*m); mtag != NULL;
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mtag = m_tag_next(*m, mtag)) {
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if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
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continue;
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if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
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mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
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continue;
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/*
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* Check if policy has an SA associated with it.
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* This can happen when an SP has yet to acquire
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* an SA; e.g. on first reference. If it occurs,
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* then we let ipsec4_process_packet do its thing.
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*/
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if (sp->req->sav == NULL)
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break;
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tdbi = (struct tdb_ident *)(mtag + 1);
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if (tdbi->spi == sp->req->sav->spi &&
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tdbi->proto == sp->req->sav->sah->saidx.proto &&
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bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
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sizeof (union sockaddr_union)) == 0) {
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/*
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* No IPsec processing is needed, free
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* reference to SP.
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*
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* NB: null pointer to avoid free at
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* done: below.
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*/
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KEY_FREESP(&sp), sp = NULL;
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splx(s);
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goto done;
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}
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}
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/*
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* Do delayed checksums now because we send before
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* this is done in the normal processing path.
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*/
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if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
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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;
|
|
}
|
|
|