NetBSD-5.0.2/sys/netinet6/esp_output.c
/* $NetBSD: esp_output.c,v 1.32 2008/04/23 06:09:05 thorpej Exp $ */
/* $KAME: esp_output.c,v 1.44 2001/07/26 06:53:15 jinmei 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.
*/
/*
* RFC1827/2406 Encapsulated Security Payload.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: esp_output.c,v 1.32 2008/04/23 06:09:05 thorpej Exp $");
#include "opt_inet.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/socketvar.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 <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_var.h>
#ifdef IPSEC_NAT_T
#include <netinet/udp.h>
#endif
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#endif
#include <netinet6/ipsec.h>
#include <netinet6/ipsec_private.h>
#include <netinet6/ah.h>
#include <netinet6/esp.h>
#include <netkey/key.h>
#include <netkey/keydb.h>
#include <net/net_osdep.h>
static int esp_output __P((struct mbuf *, u_char *, struct mbuf *,
struct ipsecrequest *, int));
/*
* compute ESP header size.
*/
size_t
esp_hdrsiz(struct ipsecrequest *isr)
{
struct secasvar *sav;
const struct esp_algorithm *algo;
const struct ah_algorithm *aalgo;
size_t ivlen;
size_t authlen;
size_t hdrsiz;
/* sanity check */
if (isr == NULL)
panic("esp_hdrsiz: NULL was passed.");
sav = isr->sav;
if (isr->saidx.proto != IPPROTO_ESP)
panic("unsupported mode passed to esp_hdrsiz");
if (sav == NULL)
goto estimate;
if (sav->state != SADB_SASTATE_MATURE
&& sav->state != SADB_SASTATE_DYING)
goto estimate;
/* we need transport mode ESP. */
algo = esp_algorithm_lookup(sav->alg_enc);
if (!algo)
goto estimate;
ivlen = sav->ivlen;
#if 0
if (ivlen < 0)
goto estimate;
#endif
/*
* XXX
* right now we don't calcurate the padding size. simply
* treat the padding size as constant, for simplicity.
*
* XXX variable size padding support
*/
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1827 */
hdrsiz = sizeof(struct esp) + ivlen +
esp_max_padbound() - 1 + 2;
} else {
/* RFC 2406 */
aalgo = ah_algorithm_lookup(sav->alg_auth);
if (aalgo && sav->replay && sav->key_auth)
authlen = (aalgo->sumsiz)(sav);
else
authlen = 0;
hdrsiz = sizeof(struct newesp) + ivlen +
esp_max_padbound() - 1 + 2 + authlen;
}
#ifdef IPSEC_NAT_T
/*
* If NAT-T is enabled, add the space for UDP encapsulation
*/
if (sav->natt_type != 0) {
hdrsiz += sizeof(struct udphdr);
if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
hdrsiz += sizeof(u_int64_t);
}
#endif
return hdrsiz;
estimate:
/*
* ASSUMING:
* sizeof(struct newesp) > sizeof(struct esp).
* esp_max_ivlen() = max ivlen for CBC mode
* esp_max_padbound - 1 =
* maximum padding length without random padding length
* 2 = (Pad Length field) + (Next Header field).
* AH_MAXSUMSIZE = maximum ICV we support.
* sizeof(u_int64_t) = non IKE marker (NAT-T)
* sizeof(struct udphdr) = UDP encapsulation (NAT-T)
*/
return sizeof(struct newesp) + esp_max_ivlen() +
esp_max_padbound() - 1 + 2 + AH_MAXSUMSIZE +
#ifdef IPSEC_NAT_T
sizeof(u_int64_t) + sizeof(struct udphdr) +
#endif
0;
}
/*
* Modify the packet so that the payload is encrypted.
* The mbuf (m) must start with IPv4 or IPv6 header.
* On failure, free the given mbuf and return NULL.
*
* on invocation:
* m nexthdrp md
* v v v
* IP ......... payload
* during the encryption:
* m nexthdrp mprev md
* v v v v
* IP ............... esp iv payload pad padlen nxthdr
* <--><-><------><--------------->
* esplen plen extendsiz
* ivlen
* <-----> esphlen
* <-> hlen
* <-----------------> espoff
*/
static int
esp_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
struct ipsecrequest *isr, int af)
{
struct mbuf *n;
struct mbuf *mprev;
struct esp *esp;
struct esptail *esptail;
struct secasvar *sav = isr->sav;
const struct esp_algorithm *algo;
u_int32_t spi;
u_int8_t nxt = 0;
size_t plen; /* payload length to be encrypted */
size_t espoff;
int ivlen;
int afnumber;
size_t extendsiz;
int error = 0;
percpu_t *stat;
#ifdef IPSEC_NAT_T
struct udphdr *udp = NULL;
#endif
switch (af) {
#ifdef INET
case AF_INET:
afnumber = 4;
stat = ipsecstat_percpu;
break;
#endif
#ifdef INET6
case AF_INET6:
afnumber = 6;
stat = ipsec6stat_percpu;
break;
#endif
default:
ipseclog((LOG_ERR, "esp_output: unsupported af %d\n", af));
return 0; /* no change at all */
}
/* some sanity check */
if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
switch (af) {
#ifdef INET
case AF_INET:
{
struct ip *ip;
ip = mtod(m, struct ip *);
ipseclog((LOG_DEBUG, "esp4_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)));
IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
break;
}
#endif /* INET */
#ifdef INET6
case AF_INET6:
ipseclog((LOG_DEBUG, "esp6_output: internal error: "
"sav->replay is null: SPI=%u\n",
(u_int32_t)ntohl(sav->spi)));
IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL);
break;
#endif /* INET6 */
default:
panic("esp_output: should not reach here");
}
error = EINVAL;
goto fail;
}
algo = esp_algorithm_lookup(sav->alg_enc);
if (!algo) {
ipseclog((LOG_ERR, "esp_output: unsupported algorithm: "
"SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
error = EINVAL;
goto fail;
}
spi = sav->spi;
ivlen = sav->ivlen;
/* should be okey */
if (ivlen < 0) {
panic("invalid ivlen");
}
{
/*
* insert ESP header.
* XXX inserts ESP header right after IPv4 header. should
* chase the header chain.
* XXX sequential number
*/
#ifdef INET
struct ip *ip = NULL;
#endif
#ifdef INET6
struct ip6_hdr *ip6 = NULL;
#endif
size_t esplen; /* sizeof(struct esp/newesp) */
size_t esphlen; /* sizeof(struct esp/newesp) + ivlen */
size_t hlen = 0; /* ip header len */
if (sav->flags & SADB_X_EXT_OLD) {
/* RFC 1827 */
esplen = sizeof(struct esp);
} else {
/* RFC 2406 */
if (sav->flags & SADB_X_EXT_DERIV)
esplen = sizeof(struct esp);
else
esplen = sizeof(struct newesp);
}
esphlen = esplen + ivlen;
for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
;
if (mprev == NULL || mprev->m_next != md) {
ipseclog((LOG_DEBUG, "esp%d_output: md is not in chain\n",
afnumber));
error = EINVAL;
goto fail;
}
plen = 0;
for (n = md; n; n = n->m_next)
plen += n->m_len;
switch (af) {
#ifdef INET
case AF_INET:
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
break;
#endif
#ifdef INET6
case AF_INET6:
ip6 = mtod(m, struct ip6_hdr *);
hlen = sizeof(*ip6);
break;
#endif
}
/* make the packet over-writable */
mprev->m_next = NULL;
if ((md = ipsec_copypkt(md)) == NULL) {
error = ENOBUFS;
goto fail;
}
mprev->m_next = md;
espoff = m->m_pkthdr.len - plen;
#ifdef IPSEC_NAT_T
if (sav->natt_type != 0) {
esphlen += sizeof(struct udphdr);
espoff += sizeof(struct udphdr);
if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
/* NON-IKE marker */
esphlen += sizeof(u_int64_t);
espoff += sizeof(u_int64_t);
}
}
#endif
/*
* grow the mbuf to accommodate ESP header.
* before: IP ... payload
* after (without NAT-T): IP ... ESP IV payload
* after (with older NAT-T): IP ... UDP non-IKE-marker ESP IV payload
* after (with newer NAT-T): IP ... UDP ESP IV payload
*/
if (M_LEADINGSPACE(md) < esphlen || (md->m_flags & M_EXT) != 0) {
MGET(n, M_DONTWAIT, MT_DATA);
if (!n) {
error = ENOBUFS;
goto fail;
}
n->m_len = esphlen;
mprev->m_next = n;
n->m_next = md;
m->m_pkthdr.len += esphlen;
esp = mtod(n, struct esp *);
} else {
md->m_len += esphlen;
md->m_data -= esphlen;
m->m_pkthdr.len += esphlen;
esp = mtod(md, struct esp *);
}
#ifdef IPSEC_NAT_T
if (sav->natt_type != 0) {
udp = (struct udphdr *)esp;
esp = (struct esp *)(udp + 1);
if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
u_int64_t *data = (u_int64_t *)esp;
*data = 0; /* NON-IKE marker */
esp = (struct esp *)(data + 1);
}
}
#endif
nxt = *nexthdrp;
*nexthdrp = IPPROTO_ESP;
switch (af) {
#ifdef INET
case AF_INET:
if (esphlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
ip->ip_len = htons(ntohs(ip->ip_len) + esphlen);
else {
ipseclog((LOG_ERR,
"IPv4 ESP output: size exceeds limit\n"));
IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
error = EMSGSIZE;
goto fail;
}
break;
#endif
#ifdef INET6
case AF_INET6:
/* total packet length will be computed in ip6_output() */
break;
#endif
}
}
/* initialize esp header. */
esp->esp_spi = spi;
if ((sav->flags & SADB_X_EXT_OLD) == 0) {
struct newesp *nesp;
nesp = (struct newesp *)esp;
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)));
_NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
error = EINVAL;
goto fail;
}
}
sav->replay->count++;
/*
* XXX sequence number must not be cycled, if the SA is
* installed by IKE daemon.
*/
nesp->esp_seq = htonl(sav->replay->count & 0xffffffff);
}
{
/*
* find the last mbuf. make some room for ESP trailer.
*/
#ifdef INET
struct ip *ip = NULL;
#endif
size_t padbound;
u_char *extend;
int i;
if (algo->padbound)
padbound = algo->padbound;
else
padbound = 4;
/* ESP packet, including nxthdr field, must be length of 4n */
if (padbound < 4)
padbound = 4;
extendsiz = padbound - (plen % padbound);
if (extendsiz == 1)
extendsiz = padbound + 1;
n = m;
while (n->m_next)
n = n->m_next;
/*
* if M_EXT, the external mbuf data may be shared among
* two consequtive TCP packets, and it may be unsafe to use the
* trailing space.
*/
if (!(n->m_flags & M_EXT) && extendsiz < M_TRAILINGSPACE(n)) {
extend = mtod(n, u_char *) + n->m_len;
n->m_len += extendsiz;
m->m_pkthdr.len += extendsiz;
} else {
struct mbuf *nn;
MGET(nn, M_DONTWAIT, MT_DATA);
if (!nn) {
ipseclog((LOG_DEBUG, "esp%d_output: can't alloc mbuf",
afnumber));
error = ENOBUFS;
goto fail;
}
extend = mtod(nn, u_char *);
nn->m_len = extendsiz;
nn->m_next = NULL;
n->m_next = nn;
n = nn;
m->m_pkthdr.len += extendsiz;
}
switch (sav->flags & SADB_X_EXT_PMASK) {
case SADB_X_EXT_PRAND:
key_randomfill(extend, extendsiz);
break;
case SADB_X_EXT_PZERO:
bzero(extend, extendsiz);
break;
case SADB_X_EXT_PSEQ:
for (i = 0; i < extendsiz; i++)
extend[i] = (i + 1) & 0xff;
break;
}
#ifdef IPSEC_NAT_T
if (sav->natt_type != 0) {
*nexthdrp = IPPROTO_UDP;
/*
* Create the UDP encapsulation header for NAT-T
* uh_len is set later, when the size is known.
*/
if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
udp->uh_sport = htons(UDP_ENCAP_ESPINUDP_PORT);
else
udp->uh_sport =
KEY_PORTFROMSADDR(&sav->sah->saidx.src);
udp->uh_dport = KEY_PORTFROMSADDR(&sav->sah->saidx.dst);
udp->uh_sum = 0;
} else {
*nexthdrp = IPPROTO_ESP;
}
#endif
/* initialize esp trailer. */
esptail = (struct esptail *)
(mtod(n, u_int8_t *) + n->m_len - sizeof(struct esptail));
esptail->esp_nxt = nxt;
esptail->esp_padlen = extendsiz - 2;
/* modify IP header (for ESP header part only) */
switch (af) {
#ifdef INET
case AF_INET:
ip = mtod(m, struct ip *);
if (extendsiz < (IP_MAXPACKET - ntohs(ip->ip_len)))
ip->ip_len = htons(ntohs(ip->ip_len) + extendsiz);
else {
ipseclog((LOG_ERR,
"IPv4 ESP output: size exceeds limit\n"));
IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
error = EMSGSIZE;
goto fail;
}
break;
#endif
#ifdef INET6
case AF_INET6:
/* total packet length will be computed in ip6_output() */
break;
#endif
}
}
/*
* pre-compute and cache intermediate key
*/
error = esp_schedule(algo, sav);
if (error) {
_NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
goto fail;
}
/*
* encrypt the packet, based on security association
* and the algorithm specified.
*/
if (!algo->encrypt)
panic("internal error: no encrypt function");
if ((*algo->encrypt)(m, espoff, plen + extendsiz, sav, algo, ivlen)) {
/* m is already freed */
m = NULL;
ipseclog((LOG_ERR, "packet encryption failure\n"));
_NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
error = EINVAL;
goto fail;
}
/*
* calculate ICV if required.
*/
if (!sav->replay)
goto noantireplay;
if (!sav->key_auth)
goto noantireplay;
if (sav->key_auth == SADB_AALG_NONE)
goto noantireplay;
{
const struct ah_algorithm *aalgo;
u_char authbuf[AH_MAXSUMSIZE];
u_char *p;
size_t siz;
#ifdef INET
struct ip *ip;
#endif
aalgo = ah_algorithm_lookup(sav->alg_auth);
if (!aalgo)
goto noantireplay;
siz = ((aalgo->sumsiz)(sav) + 3) & ~(4 - 1);
if (AH_MAXSUMSIZE < siz)
panic("assertion failed for AH_MAXSUMSIZE");
if (esp_auth(m, espoff, m->m_pkthdr.len - espoff, sav, authbuf)) {
ipseclog((LOG_ERR, "ESP checksum generation failure\n"));
error = EINVAL;
_NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
goto fail;
}
n = m;
while (n->m_next)
n = n->m_next;
if (!(n->m_flags & M_EXT) && siz < M_TRAILINGSPACE(n)) { /* XXX */
n->m_len += siz;
m->m_pkthdr.len += siz;
p = mtod(n, u_char *) + n->m_len - siz;
} else {
struct mbuf *nn;
MGET(nn, M_DONTWAIT, MT_DATA);
if (!nn) {
ipseclog((LOG_DEBUG, "can't alloc mbuf in esp%d_output",
afnumber));
error = ENOBUFS;
goto fail;
}
nn->m_len = siz;
nn->m_next = NULL;
n->m_next = nn;
n = nn;
m->m_pkthdr.len += siz;
p = mtod(nn, u_char *);
}
bcopy(authbuf, p, siz);
/* modify IP header (for ESP header part only) */
switch (af) {
#ifdef INET
case AF_INET:
ip = mtod(m, struct ip *);
if (siz < (IP_MAXPACKET - ntohs(ip->ip_len)))
ip->ip_len = htons(ntohs(ip->ip_len) + siz);
else {
ipseclog((LOG_ERR,
"IPv4 ESP output: size exceeds limit\n"));
IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
error = EMSGSIZE;
goto fail;
}
break;
#endif
#ifdef INET6
case AF_INET6:
/* total packet length will be computed in ip6_output() */
break;
#endif
}
}
noantireplay:
#ifdef IPSEC_NAT_T
if (sav->natt_type != 0) {
struct ip *ip;
ip = mtod(m, struct ip *);
udp->uh_ulen = htons(ntohs(ip->ip_len) - (ip->ip_hl << 2));
}
#endif /* IPSEC_NAT_T */
if (!m) {
ipseclog((LOG_ERR,
"NULL mbuf after encryption in esp%d_output", afnumber));
} else
_NET_STATINC(stat, IPSEC_STAT_OUT_SUCCESS);
_NET_STATINC(stat, IPSEC_STAT_OUT_ESPHIST + sav->alg_enc);
key_sa_recordxfer(sav, m);
return 0;
fail:
m_freem(m);
#if 1
return error;
#else
panic("something bad in esp_output");
#endif
}
#ifdef INET
int
esp4_output(struct mbuf *m, struct ipsecrequest *isr)
{
struct ip *ip;
if (m->m_len < sizeof(struct ip)) {
ipseclog((LOG_DEBUG, "esp4_output: first mbuf too short\n"));
m_freem(m);
return EINVAL;
}
ip = mtod(m, struct ip *);
/* XXX assumes that m->m_next points to payload */
return esp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
}
#endif /* INET */
#ifdef INET6
int
esp6_output(struct mbuf *m, u_char *nexthdrp,
struct mbuf *md, struct ipsecrequest *isr)
{
if (m->m_len < sizeof(struct ip6_hdr)) {
ipseclog((LOG_DEBUG, "esp6_output: first mbuf too short\n"));
m_freem(m);
return EINVAL;
}
return esp_output(m, nexthdrp, md, isr, AF_INET6);
}
#endif /* INET6 */