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freebsd/sys/netinet6/ah_input.c
Yoshinobu Inoue 6a800098cc IPSEC support in the kernel.
pr_input() routines prototype is also changed to support IPSEC and IPV6
chained protocol headers.

Reviewed by: freebsd-arch, cvs-committers
Obtained from: KAME project
1999-12-22 19:13:38 +00:00

709 lines
17 KiB
C

/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* 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.
* 3. Neither the name of the project 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 PROJECT 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 PROJECT 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.
*
* $FreeBSD$
*/
/*
* RFC1826/2402 authentication header.
*/
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <net/route.h>
#include <net/netisr.h>
#include <machine/cpu.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_ecn.h>
#ifdef INET6
#include <netinet6/ip6_ecn.h>
#endif
#ifdef INET6
#include <netinet6/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/icmp6.h>
#endif
#include <netinet6/ipsec.h>
#include <netinet6/ah.h>
#ifdef INET6
#include <netinet6/ipsec6.h>
#include <netinet6/ah6.h>
#endif
#include <netkey/key.h>
#include <netkey/keydb.h>
#ifdef IPSEC_DEBUG
#include <netkey/key_debug.h>
#else
#define KEYDEBUG(lev,arg)
#endif
#include <netinet/ipprotosw.h>
#include <machine/stdarg.h>
#include <net/net_osdep.h>
#ifdef INET
extern struct ipprotosw inetsw[];
void
ah4_input(m, off, proto)
struct mbuf *m;
int off, proto;
{
struct ip *ip;
struct ah *ah;
u_int32_t spi;
struct ah_algorithm *algo;
size_t siz;
size_t siz1;
u_char *cksum;
struct secasvar *sav = NULL;
u_int16_t nxt;
size_t hlen;
int s;
if (m->m_len < off + sizeof(struct newah)) {
m = m_pullup(m, off + sizeof(struct newah));
if (!m) {
printf("IPv4 AH input: can't pullup;"
"dropping the packet for simplicity\n");
ipsecstat.in_inval++;
goto fail;
}
}
ip = mtod(m, struct ip *);
ah = (struct ah *)(((caddr_t)ip) + off);
nxt = ah->ah_nxt;
#ifdef _IP_VHL
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
#else
hlen = ip->ip_hl << 2;
#endif
/* find the sassoc. */
spi = ah->ah_spi;
if ((sav = key_allocsa(AF_INET,
(caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst,
IPPROTO_AH, spi)) == 0) {
printf("IPv4 AH input: no key association found for spi %u;"
"dropping the packet for simplicity\n",
(u_int32_t)ntohl(spi));
ipsecstat.in_nosa++;
goto fail;
}
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP ah4_input called to allocate SA:%p\n", sav));
if (sav->state != SADB_SASTATE_MATURE
&& sav->state != SADB_SASTATE_DYING) {
printf("IPv4 AH input: non-mature/dying SA found for spi %u; "
"dropping the packet for simplicity\n",
(u_int32_t)ntohl(spi));
ipsecstat.in_badspi++;
goto fail;
}
if (sav->alg_auth == SADB_AALG_NONE) {
printf("IPv4 AH input: unspecified authentication algorithm "
"for spi %u;"
"dropping the packet for simplicity\n",
(u_int32_t)ntohl(spi));
ipsecstat.in_badspi++;
goto fail;
}
algo = &ah_algorithms[sav->alg_auth];
siz = (*algo->sumsiz)(sav);
siz1 = ((siz + 3) & ~(4 - 1));
/*
* sanity checks for header, 1.
*/
{
int sizoff;
sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
if ((ah->ah_len << 2) - sizoff != siz1) {
log(LOG_NOTICE, "sum length mismatch in IPv4 AH input "
"(%d should be %u): %s\n",
(ah->ah_len << 2) - sizoff, (unsigned int)siz1,
ipsec4_logpacketstr(ip, spi));
ipsecstat.in_inval++;
goto fail;
}
if (m->m_len < off + sizeof(struct ah) + sizoff + siz1) {
m = m_pullup(m, off + sizeof(struct ah) + sizoff + siz1);
if (!m) {
printf("IPv4 AH input: can't pullup;"
"dropping the packet for simplicity\n");
ipsecstat.in_inval++;
goto fail;
}
ip = mtod(m, struct ip *);
ah = (struct ah *)(((caddr_t)ip) + off);
}
}
/*
* check for sequence number.
*/
if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
; /*okey*/
else {
ipsecstat.in_ahreplay++;
log(LOG_AUTH, "replay packet in IPv4 AH input: %s %s\n",
ipsec4_logpacketstr(ip, spi),
ipsec_logsastr(sav));
goto fail;
}
}
/*
* alright, it seems sane. now we are going to check the
* cryptographic checksum.
*/
cksum = malloc(siz1, M_TEMP, M_NOWAIT);
if (!cksum) {
printf("IPv4 AH input: couldn't alloc temporary region for cksum\n");
ipsecstat.in_inval++;
goto fail;
}
{
/*
* some of IP header fields are flipped to the host endian.
* convert them back to network endian. VERY stupid.
*/
ip->ip_len = htons(ip->ip_len + hlen);
ip->ip_id = htons(ip->ip_id);
ip->ip_off = htons(ip->ip_off);
if (ah4_calccksum(m, (caddr_t)cksum, algo, sav)) {
free(cksum, M_TEMP);
ipsecstat.in_inval++;
goto fail;
}
ipsecstat.in_ahhist[sav->alg_auth]++;
/*
* flip them back.
*/
ip->ip_len = ntohs(ip->ip_len) - hlen;
ip->ip_id = ntohs(ip->ip_id);
ip->ip_off = ntohs(ip->ip_off);
}
{
caddr_t sumpos = NULL;
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
sumpos = (caddr_t)(ah + 1);
} else {
/* RFC 2402 */
sumpos = (caddr_t)(((struct newah *)ah) + 1);
}
if (bcmp(sumpos, cksum, siz) != 0) {
log(LOG_AUTH, "checksum mismatch in IPv4 AH input: %s %s\n",
ipsec4_logpacketstr(ip, spi),
ipsec_logsastr(sav));
free(cksum, M_TEMP);
ipsecstat.in_ahauthfail++;
goto fail;
}
}
free(cksum, M_TEMP);
m->m_flags |= M_AUTHIPHDR;
m->m_flags |= M_AUTHIPDGM;
/* M_AUTH related flags might be cleared here in the future */
if (m->m_flags & M_AUTHIPHDR
&& m->m_flags & M_AUTHIPDGM) {
ipsecstat.in_ahauthsucc++;
} else {
log(LOG_AUTH, "authentication failed in IPv4 AH input: %s %s\n",
ipsec4_logpacketstr(ip, spi),
ipsec_logsastr(sav));
ipsecstat.in_ahauthfail++;
}
/*
* update sequence number.
*/
if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
(void)ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav);
}
/* was it transmitted over the IPsec tunnel SA? */
if (ipsec4_tunnel_validate(ip, nxt, sav) && nxt == IPPROTO_IPV4) {
/*
* strip off all the headers that precedes AH.
* IP xx AH IP' payload -> IP' payload
*
* XXX more sanity checks
* XXX relationship with gif?
*/
size_t stripsiz = 0;
u_int8_t tos;
tos = ip->ip_tos;
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
stripsiz = sizeof(struct ah) + siz1;
} else {
/* RFC 2402 */
stripsiz = sizeof(struct newah) + siz1;
}
m_adj(m, off + stripsiz);
if (m->m_len < sizeof(*ip)) {
m = m_pullup(m, sizeof(*ip));
if (!m) {
ipsecstat.in_inval++;
goto fail;
}
}
ip = mtod(m, struct ip *);
/* ECN consideration. */
ip_ecn_egress(ip4_ipsec_ecn, &tos, &ip->ip_tos);
if (!key_checktunnelsanity(sav, AF_INET,
(caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst)) {
log(LOG_NOTICE, "ipsec tunnel address mismatch in IPv4 AH input: %s %s\n",
ipsec4_logpacketstr(ip, spi),
ipsec_logsastr(sav));
ipsecstat.in_inval++;
goto fail;
}
/*
* Should the inner packet be considered authentic?
* My current answer is: NO.
*
* host1 -- gw1 === gw2 -- host2
* In this case, gw2 can trust the authenticity of the
* outer packet, but NOT inner. Packet may be altered
* between host1 and gw1.
*
* host1 -- gw1 === host2
* This case falls into the same scenario as above.
*
* host1 === host2
* This case is the only case when we may be able to leave
* M_AUTHIPHDR and M_AUTHIPDGM set.
* However, if host1 is wrongly configured, and allows
* attacker to inject some packet with src=host1 and
* dst=host2, you are in risk.
*/
m->m_flags &= ~M_AUTHIPHDR;
m->m_flags &= ~M_AUTHIPDGM;
key_sa_recordxfer(sav, m);
s = splimp();
if (IF_QFULL(&ipintrq)) {
ipsecstat.in_inval++;
goto fail;
}
IF_ENQUEUE(&ipintrq, m);
m = NULL;
schednetisr(NETISR_IP); /*can be skipped but to make sure*/
splx(s);
nxt = IPPROTO_DONE;
} else {
/*
* strip off AH.
* We do deep-copy since KAME requires that
* the packet is placed in a single external mbuf.
*/
size_t stripsiz = 0;
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
stripsiz = sizeof(struct ah) + siz1;
} else {
/* RFC 2402 */
stripsiz = sizeof(struct newah) + siz1;
}
ip = mtod(m, struct ip *);
ovbcopy((caddr_t)ip, (caddr_t)(((u_char *)ip) + stripsiz), off);
m->m_data += stripsiz;
m->m_len -= stripsiz;
m->m_pkthdr.len -= stripsiz;
ip = mtod(m, struct ip *);
/*ip_len is in host endian*/
ip->ip_len = ip->ip_len - stripsiz;
ip->ip_p = nxt;
/* forget about IP hdr checksum, the check has already been passed */
if (nxt != IPPROTO_DONE)
(*inetsw[ip_protox[nxt]].pr_input)(m, off, nxt);
else
m_freem(m);
m = NULL;
}
if (sav) {
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP ah4_input call free SA:%p\n", sav));
key_freesav(sav);
}
ipsecstat.in_success++;
return;
fail:
if (sav) {
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP ah4_input call free SA:%p\n", sav));
key_freesav(sav);
}
if (m)
m_freem(m);
return;
}
#endif /* INET */
#ifdef INET6
int
ah6_input(mp, offp, proto)
struct mbuf **mp;
int *offp, proto;
{
struct mbuf *m = *mp;
int off = *offp;
struct ip6_hdr *ip6;
struct ah *ah;
u_int32_t spi;
struct ah_algorithm *algo;
size_t siz;
size_t siz1;
u_char *cksum;
struct secasvar *sav = NULL;
u_int16_t nxt;
int s;
IP6_EXTHDR_CHECK(m, off, sizeof(struct ah), IPPROTO_DONE);
ip6 = mtod(m, struct ip6_hdr *);
ah = (struct ah *)(((caddr_t)ip6) + off);
nxt = ah->ah_nxt;
/* find the sassoc. */
spi = ah->ah_spi;
if (ntohs(ip6->ip6_plen) == 0) {
printf("IPv6 AH input: AH with IPv6 jumbogram is not supported.\n");
ipsec6stat.in_inval++;
goto fail;
}
if ((sav = key_allocsa(AF_INET6,
(caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst,
IPPROTO_AH, spi)) == 0) {
printf("IPv6 AH input: no key association found for spi %u;"
"dropping the packet for simplicity\n",
(u_int32_t)ntohl(spi));
ipsec6stat.in_nosa++;
goto fail;
}
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP ah6_input called to allocate SA:%p\n", sav));
if (sav->state != SADB_SASTATE_MATURE
&& sav->state != SADB_SASTATE_DYING) {
printf("IPv6 AH input: non-mature/dying SA found for spi %u; "
"dropping the packet for simplicity\n",
(u_int32_t)ntohl(spi));
ipsec6stat.in_badspi++;
goto fail;
}
if (sav->alg_auth == SADB_AALG_NONE) {
printf("IPv6 AH input: unspecified authentication algorithm "
"for spi %u;"
"dropping the packet for simplicity\n",
(u_int32_t)ntohl(spi));
ipsec6stat.in_badspi++;
goto fail;
}
algo = &ah_algorithms[sav->alg_auth];
siz = (*algo->sumsiz)(sav);
siz1 = ((siz + 3) & ~(4 - 1));
/*
* sanity checks for header, 1.
*/
{
int sizoff;
sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
if ((ah->ah_len << 2) - sizoff != siz1) {
log(LOG_NOTICE, "sum length mismatch in IPv6 AH input "
"(%d should be %u): %s\n",
(ah->ah_len << 2) - sizoff, (unsigned int)siz1,
ipsec6_logpacketstr(ip6, spi));
ipsec6stat.in_inval++;
goto fail;
}
IP6_EXTHDR_CHECK(m, off, sizeof(struct ah) + sizoff + siz1, IPPROTO_DONE);
}
/*
* check for sequence number.
*/
if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
; /*okey*/
else {
ipsec6stat.in_ahreplay++;
log(LOG_AUTH, "replay packet in IPv6 AH input: %s %s\n",
ipsec6_logpacketstr(ip6, spi),
ipsec_logsastr(sav));
goto fail;
}
}
/*
* alright, it seems sane. now we are going to check the
* cryptographic checksum.
*/
cksum = malloc(siz1, M_TEMP, M_NOWAIT);
if (!cksum) {
printf("IPv6 AH input: couldn't alloc temporary region for cksum\n");
ipsec6stat.in_inval++;
goto fail;
}
if (ah6_calccksum(m, (caddr_t)cksum, algo, sav)) {
free(cksum, M_TEMP);
ipsec6stat.in_inval++;
goto fail;
}
ipsec6stat.in_ahhist[sav->alg_auth]++;
{
caddr_t sumpos = NULL;
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
sumpos = (caddr_t)(ah + 1);
} else {
/* RFC 2402 */
sumpos = (caddr_t)(((struct newah *)ah) + 1);
}
if (bcmp(sumpos, cksum, siz) != 0) {
log(LOG_AUTH, "checksum mismatch in IPv6 AH input: %s %s\n",
ipsec6_logpacketstr(ip6, spi),
ipsec_logsastr(sav));
free(cksum, M_TEMP);
ipsec6stat.in_ahauthfail++;
goto fail;
}
}
free(cksum, M_TEMP);
m->m_flags |= M_AUTHIPHDR;
m->m_flags |= M_AUTHIPDGM;
/* M_AUTH related flags might be cleared here in the future */
if (m->m_flags & M_AUTHIPHDR
&& m->m_flags & M_AUTHIPDGM) {
ipsec6stat.in_ahauthsucc++;
} else {
log(LOG_AUTH, "authentication failed in IPv6 AH input: %s %s\n",
ipsec6_logpacketstr(ip6, spi),
ipsec_logsastr(sav));
ipsec6stat.in_ahauthfail++;
}
/*
* update sequence number.
*/
if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
(void)ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav);
}
/* was it transmitted over the IPsec tunnel SA? */
if (ipsec6_tunnel_validate(ip6, nxt, sav) && nxt == IPPROTO_IPV6) {
/*
* strip off all the headers that precedes AH.
* IP6 xx AH IP6' payload -> IP6' payload
*
* XXX more sanity checks
* XXX relationship with gif?
*/
size_t stripsiz = 0;
u_int32_t flowinfo; /*net endian*/
flowinfo = ip6->ip6_flow;
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
stripsiz = sizeof(struct ah) + siz1;
} else {
/* RFC 2402 */
stripsiz = sizeof(struct newah) + siz1;
}
m_adj(m, off + stripsiz);
if (m->m_len < sizeof(*ip6)) {
/*
* m_pullup is prohibited in KAME IPv6 input processing
* but there's no other way!
*/
m = m_pullup(m, sizeof(*ip6));
if (!m) {
ipsec6stat.in_inval++;
goto fail;
}
}
ip6 = mtod(m, struct ip6_hdr *);
/* ECN consideration. */
ip6_ecn_egress(ip6_ipsec_ecn, &flowinfo, &ip6->ip6_flow);
if (!key_checktunnelsanity(sav, AF_INET6,
(caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst)) {
log(LOG_NOTICE, "ipsec tunnel address mismatch in IPv6 AH input: %s %s\n",
ipsec6_logpacketstr(ip6, spi),
ipsec_logsastr(sav));
ipsec6stat.in_inval++;
goto fail;
}
/*
* should the inner packet be considered authentic?
* see comment in ah4_input().
*/
m->m_flags &= ~M_AUTHIPHDR;
m->m_flags &= ~M_AUTHIPDGM;
key_sa_recordxfer(sav, m);
s = splimp();
if (IF_QFULL(&ip6intrq)) {
ipsec6stat.in_inval++;
goto fail;
}
IF_ENQUEUE(&ip6intrq, m);
m = NULL;
schednetisr(NETISR_IPV6); /*can be skipped but to make sure*/
splx(s);
nxt = IPPROTO_DONE;
} else {
/*
* strip off AH.
* We do deep-copy since KAME requires that
* the packet is placed in a single mbuf.
*/
size_t stripsiz = 0;
char *prvnxtp;
/*
* Copy the value of the next header field of AH to the
* next header field of the previous header.
* This is necessary because AH will be stripped off below.
*/
prvnxtp = ip6_get_prevhdr(m, off); /* XXX */
*prvnxtp = nxt;
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
stripsiz = sizeof(struct ah) + siz1;
} else {
/* RFC 2402 */
stripsiz = sizeof(struct newah) + siz1;
}
ip6 = mtod(m, struct ip6_hdr *);
ovbcopy((caddr_t)ip6, (caddr_t)(((u_char *)ip6) + stripsiz),
off);
m->m_data += stripsiz;
m->m_len -= stripsiz;
m->m_pkthdr.len -= stripsiz;
ip6 = mtod(m, struct ip6_hdr *);
ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) - stripsiz);
key_sa_recordxfer(sav, m);
}
*offp = off;
*mp = m;
if (sav) {
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP ah6_input call free SA:%p\n", sav));
key_freesav(sav);
}
ipsec6stat.in_success++;
return nxt;
fail:
if (sav) {
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP ah6_input call free SA:%p\n", sav));
key_freesav(sav);
}
if (m)
m_freem(m);
return IPPROTO_DONE;
}
#endif /* INET6 */