/* $FreeBSD$ */
/* $KAME: ah_output.c,v 1.38 2003/09/06 05:15:43 itojun Exp $ */
/*
* 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.
*/
/*
* RFC1826/2402 authentication header.
*/
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_var.h>
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#endif
#include <netinet6/ipsec.h>
#ifdef INET6
#include <netinet6/ipsec6.h>
#endif
#include <netinet6/ah.h>
#ifdef INET6
#include <netinet6/ah6.h>
#endif
#include <netkey/key.h>
#include <netkey/keydb.h>
#include <net/net_osdep.h>
#ifdef INET
static struct in_addr *ah4_finaldst __P((struct mbuf *));
#endif
/*
* compute AH header size.
* transport mode only. for tunnel mode, we should implement
* virtual interface, and control MTU/MSS by the interface MTU.
*/
size_t
ah_hdrsiz(isr)
struct ipsecrequest *isr;
{
const struct ah_algorithm *algo;
size_t hdrsiz;
/* sanity check */
if (isr == NULL)
panic("ah_hdrsiz: NULL was passed.");
if (isr->saidx.proto != IPPROTO_AH)
panic("unsupported mode passed to ah_hdrsiz");
if (isr->sav == NULL)
goto estimate;
if (isr->sav->state != SADB_SASTATE_MATURE
&& isr->sav->state != SADB_SASTATE_DYING)
goto estimate;
/* we need transport mode AH. */
algo = ah_algorithm_lookup(isr->sav->alg_auth);
if (!algo)
goto estimate;
/*
* XXX
* right now we don't calcurate the padding size. simply
* treat the padding size as constant, for simplicity.
*
* XXX variable size padding support
*/
hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
if (isr->sav->flags & SADB_X_EXT_OLD)
hdrsiz += sizeof(struct ah);
else
hdrsiz += sizeof(struct newah);
return hdrsiz;
estimate:
/* ASSUMING:
* sizeof(struct newah) > sizeof(struct ah).
* AH_MAXSUMSIZE is multiple of 4.
*/
return sizeof(struct newah) + AH_MAXSUMSIZE;
}
#ifdef INET
/*
* Modify the packet so that it includes the authentication data.
* The mbuf passed must start with IPv4 header.
*
* assumes that the first mbuf contains IPv4 header + option only.
* the function does not modify m.
*/
int
ah4_output(m, isr)
struct mbuf *m;
struct ipsecrequest *isr;
{
struct secasvar *sav = isr->sav;
const struct ah_algorithm *algo;
u_int32_t spi;
u_char *ahdrpos;
u_int8_t *ahsumpos = NULL;
size_t hlen = 0; /* IP header+option in bytes */
size_t plen = 0; /* AH payload size in bytes */
size_t ahlen = 0; /* plen + sizeof(ah) */
struct ip *ip;
struct in_addr dst;
struct in_addr *finaldst;
int error;
/* sanity checks */
if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
struct ip *ip;
ip = mtod(m, struct ip *);
ipseclog((LOG_DEBUG, "ah4_output: internal error: "
"sav->replay is null: %x->%x, SPI=%u\n",
(u_int32_t)ntohl(ip->ip_src.s_addr),
(u_int32_t)ntohl(ip->ip_dst.s_addr),
(u_int32_t)ntohl(sav->spi)));
ipsecstat.out_inval++;
m_freem(m);
return EINVAL;
}
algo = ah_algorithm_lookup(sav->alg_auth);
if (!algo) {
ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
"SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
ipsecstat.out_inval++;
m_freem(m);
return EINVAL;
}
spi = sav->spi;
/*
* determine the size to grow.
*/
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
ahlen = plen + sizeof(struct ah);
} else {
/* RFC 2402 */
plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
ahlen = plen + sizeof(struct newah);
}
/*
* grow the mbuf to accomodate AH.
*/
ip = mtod(m, struct ip *);
#ifdef _IP_VHL
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
#else
hlen = ip->ip_hl << 2;
#endif
if (m->m_len != hlen)
panic("ah4_output: assumption failed (first mbuf length)");
if (M_LEADINGSPACE(m->m_next) < ahlen) {
struct mbuf *n;
MGET(n, M_DONTWAIT, MT_DATA);
if (!n) {
ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
__LINE__));
m_freem(m);
return ENOBUFS;
}
n->m_len = ahlen;
n->m_next = m->m_next;
m->m_next = n;
m->m_pkthdr.len += ahlen;
ahdrpos = mtod(n, u_char *);
} else {
m->m_next->m_len += ahlen;
m->m_next->m_data -= ahlen;
m->m_pkthdr.len += ahlen;
ahdrpos = mtod(m->m_next, u_char *);
}
ip = mtod(m, struct ip *); /* just to be sure */
/*
* initialize AH.
*/
if (sav->flags & SADB_X_EXT_OLD) {
struct ah *ahdr;
ahdr = (struct ah *)ahdrpos;
ahsumpos = (u_char *)(ahdr + 1);
ahdr->ah_len = plen >> 2;
ahdr->ah_nxt = ip->ip_p;
ahdr->ah_reserve = htons(0);
ahdr->ah_spi = spi;
bzero(ahdr + 1, plen);
} else {
struct newah *ahdr;
ahdr = (struct newah *)ahdrpos;
ahsumpos = (u_char *)(ahdr + 1);
ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
ahdr->ah_nxt = ip->ip_p;
ahdr->ah_reserve = htons(0);
ahdr->ah_spi = spi;
if (sav->replay->count == ~0) {
if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
/* XXX Is it noisy ? */
ipseclog((LOG_WARNING,
"replay counter overflowed. %s\n",
ipsec_logsastr(sav)));
ipsecstat.out_inval++;
m_freem(m);
return EINVAL;
}
}
sav->replay->count++;
/*
* XXX sequence number must not be cycled, if the SA is
* installed by IKE daemon.
*/
ahdr->ah_seq = htonl(sav->replay->count & 0xffffffff);
bzero(ahdr + 1, plen);
}
/*
* modify IPv4 header.
*/
ip->ip_p = IPPROTO_AH;
if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
else {
ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
ipsecstat.out_inval++;
m_freem(m);
return EMSGSIZE;
}
/*
* If there is source routing option, update destination field in
* the IPv4 header to the final destination.
* Note that we do not need to update source routing option itself
* (as done in IPv4 AH processing -- see ip6_output()), since
* source routing option is not part of the ICV computation.
*/
finaldst = ah4_finaldst(m);
if (finaldst) {
dst.s_addr = ip->ip_dst.s_addr;
ip->ip_dst.s_addr = finaldst->s_addr;
}
/*
* calcurate the checksum, based on security association
* and the algorithm specified.
*/
error = ah4_calccksum(m, ahsumpos, plen, algo, sav);
if (error) {
ipseclog((LOG_ERR,
"error after ah4_calccksum, called from ah4_output"));
m_freem(m);
m = NULL;
ipsecstat.out_inval++;
return error;
}
if (finaldst) {
ip = mtod(m, struct ip *); /* just to make sure */
ip->ip_dst.s_addr = dst.s_addr;
}
ipsecstat.out_success++;
ipsecstat.out_ahhist[sav->alg_auth]++;
key_sa_recordxfer(sav, m);
return 0;
}
#endif
/* Calculate AH length */
int
ah_hdrlen(sav)
struct secasvar *sav;
{
const struct ah_algorithm *algo;
int plen, ahlen;
algo = ah_algorithm_lookup(sav->alg_auth);
if (!algo)
return 0;
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1826 */
plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
ahlen = plen + sizeof(struct ah);
} else {
/* RFC 2402 */
plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
ahlen = plen + sizeof(struct newah);
}
return (ahlen);
}
#ifdef INET6
/*
* Fill in the Authentication Header and calculate checksum.
*/
int
ah6_output(m, nexthdrp, md, isr)
struct mbuf *m;
u_char *nexthdrp;
struct mbuf *md;
struct ipsecrequest *isr;
{
struct mbuf *mprev;
struct mbuf *mah;
struct secasvar *sav = isr->sav;
const struct ah_algorithm *algo;
u_int32_t spi;
u_int8_t *ahsumpos = NULL;
size_t plen; /* AH payload size in bytes */
int error = 0;
int ahlen;
struct ip6_hdr *ip6;
if (m->m_len < sizeof(struct ip6_hdr)) {
ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
m_freem(m);
return EINVAL;
}
ahlen = ah_hdrlen(sav);
if (ahlen == 0)
return 0;
for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
;
if (!mprev || mprev->m_next != md) {
ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
m_freem(m);
return EINVAL;
}
MGET(mah, M_DONTWAIT, MT_DATA);
if (!mah) {
m_freem(m);
return ENOBUFS;
}
if (ahlen > MLEN) {
MCLGET(mah, M_DONTWAIT);
if ((mah->m_flags & M_EXT) == 0) {
m_free(mah);
m_freem(m);
return ENOBUFS;
}
}
mah->m_len = ahlen;
mah->m_next = md;
mprev->m_next = mah;
m->m_pkthdr.len += ahlen;
/* fix plen */
if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
ipseclog((LOG_ERR,
"ah6_output: AH with IPv6 jumbogram is not supported\n"));
m_freem(m);
return EINVAL;
}
ip6 = mtod(m, struct ip6_hdr *);
ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
ipseclog((LOG_DEBUG, "ah6_output: internal error: "
"sav->replay is null: SPI=%u\n",
(u_int32_t)ntohl(sav->spi)));
ipsec6stat.out_inval++;
m_freem(m);
return EINVAL;
}
algo = ah_algorithm_lookup(sav->alg_auth);
if (!algo) {
ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
"SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
ipsec6stat.out_inval++;
m_freem(m);
return EINVAL;
}
spi = sav->spi;
/*
* initialize AH.
*/
if (sav->flags & SADB_X_EXT_OLD) {
struct ah *ahdr = mtod(mah, struct ah *);
plen = mah->m_len - sizeof(struct ah);
ahsumpos = (u_char *)(ahdr + 1);
ahdr->ah_nxt = *nexthdrp;
*nexthdrp = IPPROTO_AH;
ahdr->ah_len = plen >> 2;
ahdr->ah_reserve = htons(0);
ahdr->ah_spi = spi;
bzero(ahdr + 1, plen);
} else {
struct newah *ahdr = mtod(mah, struct newah *);
plen = mah->m_len - sizeof(struct newah);
ahsumpos = (u_char *)(ahdr + 1);
ahdr->ah_nxt = *nexthdrp;
*nexthdrp = IPPROTO_AH;
ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
ahdr->ah_reserve = htons(0);
ahdr->ah_spi = spi;
if (sav->replay->count == ~0) {
if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
/* XXX Is it noisy ? */
ipseclog((LOG_WARNING,
"replay counter overflowed. %s\n",
ipsec_logsastr(sav)));
ipsec6stat.out_inval++;
m_freem(m);
return EINVAL;
}
}
sav->replay->count++;
/*
* XXX sequence number must not be cycled, if the SA is
* installed by IKE daemon.
*/
ahdr->ah_seq = htonl(sav->replay->count);
bzero(ahdr + 1, plen);
}
/*
* calcurate the checksum, based on security association
* and the algorithm specified.
*/
error = ah6_calccksum(m, ahsumpos, plen, algo, sav);
if (error) {
ipsec6stat.out_inval++;
m_freem(m);
} else {
ipsec6stat.out_success++;
key_sa_recordxfer(sav, m);
}
ipsec6stat.out_ahhist[sav->alg_auth]++;
return (error);
}
#endif
#ifdef INET
/*
* Find the final destination if there is loose/strict source routing option.
* Returns NULL if there's no source routing options.
* Returns NULL on errors too.
* Note that this function will return a pointer INTO the given parameter,
* struct mbuf *m.
* The mbuf must be pulled up toward, at least, ip option part.
*/
static struct in_addr *
ah4_finaldst(m)
struct mbuf *m;
{
struct ip *ip;
int optlen;
u_char *q;
int i;
int hlen;
if (!m)
panic("ah4_finaldst: m == NULL");
ip = mtod(m, struct ip *);
hlen = (ip->ip_hl << 2);
if (m->m_len < hlen) {
ipseclog((LOG_DEBUG,
"ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
return NULL;
}
if (hlen == sizeof(struct ip))
return NULL;
optlen = hlen - sizeof(struct ip);
if (optlen < 0) {
ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
optlen));
return NULL;
}
q = (u_char *)(ip + 1);
i = 0;
while (i < optlen) {
if (i + IPOPT_OPTVAL >= optlen)
return NULL;
if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
i + IPOPT_OLEN < optlen)
;
else
return NULL;
switch (q[i + IPOPT_OPTVAL]) {
case IPOPT_EOL:
i = optlen; /* bye */
break;
case IPOPT_NOP:
i++;
break;
case IPOPT_LSRR:
case IPOPT_SSRR:
if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
optlen - i < q[i + IPOPT_OLEN]) {
ipseclog((LOG_ERR,
"ip_finaldst: invalid IP option "
"(code=%02x len=%02x)\n",
q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
return NULL;
}
i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
return (struct in_addr *)(q + i);
default:
if (q[i + IPOPT_OLEN] < 2 ||
optlen - i < q[i + IPOPT_OLEN]) {
ipseclog((LOG_ERR,
"ip_finaldst: invalid IP option "
"(code=%02x len=%02x)\n",
q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
return NULL;
}
i += q[i + IPOPT_OLEN];
break;
}
}
return NULL;
}
#endif
