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|
/* $OpenBSD: ip_esp_new.c,v 1.37 1999/02/25 18:43:42 angelos Exp $ */
/*
* The authors of this code are John Ioannidis (ji@tla.org),
* Angelos D. Keromytis (kermit@csd.uch.gr) and
* Niels Provos (provos@physnet.uni-hamburg.de).
*
* This code was written by John Ioannidis for BSD/OS in Athens, Greece,
* in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis.
*
* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
* and Niels Provos.
*
* Additional features in 1999 by Angelos D. Keromytis.
*
* Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
* Angelos D. Keromytis and Niels Provos.
*
* Permission to use, copy, and modify this software without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
* You may use this code under the GNU public license if you so wish. Please
* contribute changes back to the authors under this freer than GPL license
* so that we may further the use of strong encryption without limitations to
* all.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
/*
* Based on draft-ietf-ipsec-esp-v2-00.txt and
* draft-ietf-ipsec-ciph-{des,3des}-{derived,expiv}-00.txt
*/
#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 <machine/cpu.h>
#include <net/if.h>
#include <net/route.h>
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <sys/socketvar.h>
#include <net/raw_cb.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_ipsp.h>
#include <netinet/ip_esp.h>
#include <net/pfkeyv2.h>
#ifdef ENCDEBUG
#define DPRINTF(x) if (encdebug) printf x
#else
#define DPRINTF(x)
#endif
extern void des_ecb3_encrypt(caddr_t, caddr_t, caddr_t, caddr_t, caddr_t, int);
extern void des_ecb_encrypt(caddr_t, caddr_t, caddr_t, int);
extern void des_set_key(caddr_t, caddr_t);
static void des1_encrypt(struct tdb *, u_int8_t *);
static void des3_encrypt(struct tdb *, u_int8_t *);
static void blf_encrypt(struct tdb *, u_int8_t *);
static void cast5_encrypt(struct tdb *, u_int8_t *);
static void skipjack_encrypt(struct tdb *, u_int8_t *);
static void des1_decrypt(struct tdb *, u_int8_t *);
static void des3_decrypt(struct tdb *, u_int8_t *);
static void blf_decrypt(struct tdb *, u_int8_t *);
static void cast5_decrypt(struct tdb *, u_int8_t *);
static void skipjack_decrypt(struct tdb *, u_int8_t *);
struct auth_hash esp_new_hash[] = {
{ SADB_AALG_MD5HMAC96, "HMAC-MD5-96",
MD5HMAC96_KEYSIZE, AH_MD5_ALEN,
sizeof(MD5_CTX),
(void (*) (void *)) MD5Init,
(void (*) (void *, u_int8_t *, u_int16_t)) MD5Update,
(void (*) (u_int8_t *, void *)) MD5Final
},
{ SADB_AALG_SHA1HMAC96, "HMAC-SHA1-96",
SHA1HMAC96_KEYSIZE, AH_SHA1_ALEN,
sizeof(SHA1_CTX),
(void (*) (void *)) SHA1Init,
(void (*) (void *, u_int8_t *, u_int16_t)) SHA1Update,
(void (*) (u_int8_t *, void *)) SHA1Final
},
{ SADB_AALG_X_RIPEMD160HMAC96, "HMAC-RIPEMD-160-96",
RIPEMD160HMAC96_KEYSIZE, AH_RMD160_ALEN,
sizeof(RMD160_CTX),
(void (*)(void *)) RMD160Init,
(void (*)(void *, u_int8_t *, u_int16_t)) RMD160Update,
(void (*)(u_int8_t *, void *)) RMD160Final
}
};
struct enc_xform esp_new_xform[] = {
{ SADB_EALG_DESCBC, "Data Encryption Standard (DES)",
ESP_DES_BLKS, ESP_DES_IVS,
8, 8, 8,
des1_encrypt,
des1_decrypt
},
{ SADB_EALG_3DESCBC, "Triple DES (3DES)",
ESP_3DES_BLKS, ESP_3DES_IVS,
24, 24, 8,
des3_encrypt,
des3_decrypt
},
{ SADB_EALG_X_BLF, "Blowfish",
ESP_BLF_BLKS, ESP_BLF_IVS,
5, BLF_MAXKEYLEN, 8,
blf_encrypt,
blf_decrypt
},
{ SADB_EALG_X_CAST, "CAST",
ESP_CAST_BLKS, ESP_CAST_IVS,
5, 16, 8,
cast5_encrypt,
cast5_decrypt
},
{ SADB_EALG_X_SKIPJACK, "Skipjack",
ESP_SKIPJACK_BLKS, ESP_SKIPJACK_IVS,
10, 10, 8,
skipjack_encrypt,
skipjack_decrypt
}
};
static void
des1_encrypt(struct tdb *tdb, u_int8_t *blk)
{
des_ecb_encrypt(blk, blk, tdb->tdb_key, 1);
}
static void
des1_decrypt(struct tdb *tdb, u_int8_t *blk)
{
des_ecb_encrypt(blk, blk, tdb->tdb_key, 0);
}
static void
des3_encrypt(struct tdb *tdb, u_int8_t *blk)
{
des_ecb3_encrypt(blk, blk, tdb->tdb_key, tdb->tdb_key + 128,
tdb->tdb_key + 256, 1);
}
static void
des3_decrypt(struct tdb *tdb, u_int8_t *blk)
{
des_ecb3_encrypt(blk, blk, tdb->tdb_key + 256, tdb->tdb_key + 128,
tdb->tdb_key, 0);
}
static void
blf_encrypt(struct tdb *tdb, u_int8_t *blk)
{
blf_ecb_encrypt((blf_ctx *) tdb->tdb_key, blk, 8);
}
static void
blf_decrypt(struct tdb *tdb, u_int8_t *blk)
{
blf_ecb_decrypt((blf_ctx *) tdb->tdb_key, blk, 8);
}
static void
cast5_encrypt(struct tdb *tdb, u_int8_t *blk)
{
cast_encrypt((cast_key *) tdb->tdb_key, blk, blk);
}
static void
cast5_decrypt(struct tdb *tdb, u_int8_t *blk)
{
cast_decrypt((cast_key *) tdb->tdb_key, blk, blk);
}
static void
skipjack_encrypt(struct tdb *tdb, u_int8_t *blk)
{
skipjack_forwards(blk, blk, (u_int8_t **) tdb->tdb_key);
}
static void
skipjack_decrypt(struct tdb *tdb, u_int8_t *blk)
{
skipjack_backwards(blk, blk, (u_int8_t **) tdb->tdb_key);
}
/*
* esp_new_attach() is called from the transformation initialization code.
*/
int
esp_new_attach()
{
return 0;
}
/*
* esp_new_init() is called when an SPI is being set up.
*/
int
esp_new_init(struct tdb *tdbp, struct xformsw *xsp, struct ipsecinit *ii)
{
struct enc_xform *txform = NULL;
struct auth_hash *thash = NULL;
int i;
/* Check whether the encryption algorithm is supported */
for (i = sizeof(esp_new_xform) / sizeof(struct enc_xform) - 1;
i >= 0; i--)
if (ii->ii_encalg == esp_new_xform[i].type)
break;
if (i < 0)
{
DPRINTF(("esp_new_init(): unsupported encryption algorithm %d specified\n", ii->ii_encalg));
return EINVAL;
}
txform = &esp_new_xform[i];
if (ii->ii_enckeylen < txform->minkey)
{
DPRINTF(("esp_new_init(): keylength %d too small (min length is %d) for algorithm %s\n", ii->ii_enckeylen, txform->minkey, txform->name));
return EINVAL;
}
if (ii->ii_enckeylen > txform->maxkey)
{
DPRINTF(("esp_new_init(): keylength %d too large (max length is %d) for algorithm %s\n", ii->ii_enckeylen, txform->maxkey, txform->name));
return EINVAL;
}
if (ii->ii_authalg)
{
for (i = sizeof(esp_new_hash) / sizeof(struct auth_hash) - 1;
i >= 0; i--)
if (ii->ii_authalg == esp_new_hash[i].type)
break;
if (i < 0)
{
DPRINTF(("esp_new_init(): unsupported authentication algorithm %d specified\n", ii->ii_authalg));
return EINVAL;
}
thash = &esp_new_hash[i];
if (ii->ii_authkeylen != thash->keysize)
{
DPRINTF(("esp_new_init(): keylength %d doesn't match algorithm %s keysize (%d)\n", ii->ii_authkeylen, thash->name, thash->keysize));
return EINVAL;
}
tdbp->tdb_authalgxform = thash;
DPRINTF(("esp_new_init(): initialized TDB with hash algorithm %s\n",
thash->name));
}
tdbp->tdb_xform = xsp;
tdbp->tdb_encalgxform = txform;
tdbp->tdb_bitmap = 0;
tdbp->tdb_rpl = AH_HMAC_INITIAL_RPL;
DPRINTF(("esp_new_init(): initialized TDB with enc algorithm %s\n",
txform->name));
tdbp->tdb_ivlen = txform->ivmask;
/* Initialize the IV */
get_random_bytes(tdbp->tdb_iv, tdbp->tdb_ivlen);
switch (ii->ii_encalg)
{
case SADB_EALG_DESCBC:
MALLOC(tdbp->tdb_key, u_int8_t *, 128, M_XDATA, M_WAITOK);
bzero(tdbp->tdb_key, 128);
des_set_key(ii->ii_enckey, tdbp->tdb_key);
break;
case SADB_EALG_3DESCBC:
MALLOC(tdbp->tdb_key, u_int8_t *, 384, M_XDATA, M_WAITOK);
bzero(tdbp->tdb_key, 384);
des_set_key(ii->ii_enckey, tdbp->tdb_key);
des_set_key(ii->ii_enckey + 8, tdbp->tdb_key + 128);
des_set_key(ii->ii_enckey + 16, tdbp->tdb_key + 256);
break;
case SADB_EALG_X_BLF:
MALLOC(tdbp->tdb_key, u_int8_t *, sizeof(blf_ctx),
M_XDATA, M_WAITOK);
bzero(tdbp->tdb_key, sizeof(blf_ctx));
blf_key((blf_ctx *) tdbp->tdb_key, ii->ii_enckey,
ii->ii_enckeylen);
break;
case SADB_EALG_X_CAST:
MALLOC(tdbp->tdb_key, u_int8_t *, sizeof(cast_key),
M_XDATA, M_WAITOK);
bzero(tdbp->tdb_key, sizeof(cast_key));
cast_setkey((cast_key *) tdbp->tdb_key, ii->ii_enckey,
ii->ii_enckeylen);
break;
case SADB_EALG_X_SKIPJACK:
MALLOC(tdbp->tdb_key, u_int8_t *, 10 * sizeof(u_int8_t *),
M_XDATA, M_WAITOK);
bzero(tdbp->tdb_key, 10 * sizeof(u_int8_t *));
subkey_table_gen(ii->ii_enckey, (u_int8_t **) tdbp->tdb_key);
break;
}
if (thash)
{
/* Precompute the I and O pads of the HMAC */
for (i = 0; i < ii->ii_authkeylen; i++)
ii->ii_authkey[i] ^= HMAC_IPAD_VAL;
MALLOC(tdbp->tdb_ictx, u_int8_t *, thash->ctxsize, M_XDATA, M_WAITOK);
bzero(tdbp->tdb_ictx, thash->ctxsize);
thash->Init(tdbp->tdb_ictx);
thash->Update(tdbp->tdb_ictx, ii->ii_authkey, ii->ii_authkeylen);
thash->Update(tdbp->tdb_ictx, hmac_ipad_buffer,
HMAC_BLOCK_LEN - ii->ii_authkeylen);
for (i = 0; i < ii->ii_authkeylen; i++)
ii->ii_authkey[i] ^= (HMAC_IPAD_VAL ^ HMAC_OPAD_VAL);
MALLOC(tdbp->tdb_octx, u_int8_t *, thash->ctxsize, M_XDATA, M_WAITOK);
bzero(tdbp->tdb_octx, thash->ctxsize);
thash->Init(tdbp->tdb_octx);
thash->Update(tdbp->tdb_octx, ii->ii_authkey, ii->ii_authkeylen);
thash->Update(tdbp->tdb_octx, hmac_opad_buffer,
HMAC_BLOCK_LEN - ii->ii_authkeylen);
}
return 0;
}
int
esp_new_zeroize(struct tdb *tdbp)
{
int k;
if (tdbp->tdb_encalgxform && tdbp->tdb_key &&
tdbp->tdb_encalgxform->type == SADB_EALG_X_SKIPJACK)
for (k = 0; k < 10; k++)
if (((u_int8_t **)tdbp->tdb_key)[k] != NULL)
FREE(((u_int8_t **)tdbp->tdb_key)[k], M_XDATA);
if (tdbp->tdb_key)
{
FREE(tdbp->tdb_key, M_XDATA);
tdbp->tdb_key = NULL;
}
if (tdbp->tdb_ictx)
{
FREE(tdbp->tdb_ictx, M_XDATA);
tdbp->tdb_ictx = NULL;
}
if (tdbp->tdb_octx)
{
FREE(tdbp->tdb_octx, M_XDATA);
tdbp->tdb_octx = NULL;
}
return 0;
}
struct mbuf *
esp_new_input(struct mbuf *m, struct tdb *tdb)
{
struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform;
struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform;
u_char iv[ESP_MAX_IVS], niv[ESP_MAX_IVS];
u_char blk[ESP_MAX_BLKS], *lblk, opts[40];
int ohlen, oplen, plen, alen, ilen, i, blks, rest;
int count, off, errc;
struct mbuf *mi, *mo;
u_char *idat, *odat, *ivp, *ivn;
struct esp_new *esp;
struct ip *ip, ipo;
u_int32_t btsx;
union {
MD5_CTX md5ctx;
SHA1_CTX sha1ctx;
RMD160_CTX rmd160ctx;
} ctx;
u_char buf[AH_ALEN_MAX], buf2[AH_ALEN_MAX];
blks = espx->blocksize;
if (esph)
alen = AH_HMAC_HASHLEN;
else
alen = 0;
if (m->m_len < sizeof(struct ip))
{
if ((m = m_pullup(m, sizeof(struct ip))) == NULL)
{
DPRINTF(("esp_new_input(): (possibly too short) packet dropped\n"));
espstat.esps_hdrops++;
return NULL;
}
}
ip = mtod(m, struct ip *);
ohlen = (ip->ip_hl << 2) + ESP_NEW_FLENGTH;
/* Make sure the IP header, any IP options, and the ESP header are here */
if (m->m_len < ohlen + blks)
{
if ((m = m_pullup(m, ohlen + blks)) == NULL)
{
DPRINTF(("esp_new_input(): m_pullup() failed\n"));
espstat.esps_hdrops++;
return NULL;
}
ip = mtod(m, struct ip *);
}
/* Update the counters */
tdb->tdb_cur_bytes += ip->ip_len - ohlen - alen;
espstat.esps_ibytes += ip->ip_len - ohlen - alen;
/* Hard expiration */
if ((tdb->tdb_flags & TDBF_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes))
{
/* XXX
encap_sendnotify(NOTIFY_HARD_EXPIRE, tdb, NULL);
*/
tdb_delete(tdb, 0);
m_freem(m);
return NULL;
}
/* Notify on expiration */
if ((tdb->tdb_flags & TDBF_SOFT_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes))
{
/* XXX
encap_sendnotify(NOTIFY_SOFT_EXPIRE, tdb, NULL);
*/
tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */
}
esp = (struct esp_new *) ((u_int8_t *) ip + (ip->ip_hl << 2));
ipo = *ip;
/* Replay window checking */
if (tdb->tdb_wnd > 0)
{
btsx = ntohl(esp->esp_rpl);
if ((errc = checkreplaywindow32(btsx, 0, &(tdb->tdb_rpl), tdb->tdb_wnd,
&(tdb->tdb_bitmap))) != 0)
{
switch(errc)
{
case 1:
DPRINTF(("esp_new_input(): replay counter wrapped for packets from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi)));
espstat.esps_wrap++;
break;
case 2:
case 3:
DPRINTF(("esp_new_input(): duplicate packet received from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi)));
espstat.esps_replay++;
break;
}
m_freem(m);
return NULL;
}
}
/* Skip the IP header, IP options, SPI, SN and IV and minus Auth Data */
plen = m->m_pkthdr.len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t) -
tdb->tdb_ivlen - alen;
if ((plen & (blks - 1)) || (plen <= 0))
{
DPRINTF(("esp_new_input(): payload not a multiple of %d octets for packet from %s to %s, spi %08x\n", blks, inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi)));
espstat.esps_badilen++;
m_freem(m);
return NULL;
}
if (esph)
{
bcopy(tdb->tdb_ictx, &ctx, esph->ctxsize);
/* Auth covers SPI + SN + IV */
oplen = plen + 2 * sizeof(u_int32_t) + tdb->tdb_ivlen;
off = (ip->ip_hl << 2);
/* Copy the authentication data */
m_copydata(m, m->m_pkthdr.len - alen, alen, buf);
mo = m;
while (oplen > 0)
{
if (mo == 0)
{
DPRINTF(("esp_new_input(): bad mbuf chain for packet from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi)));
espstat.esps_hdrops++;
m_freem(m);
return NULL;
}
count = min(mo->m_len - off, oplen);
esph->Update(&ctx, mtod(mo, unsigned char *) + off, count);
oplen -= count;
off = 0;
mo = mo->m_next;
}
esph->Final(buf2, &ctx);
bcopy(tdb->tdb_octx, &ctx, esph->ctxsize);
esph->Update(&ctx, buf2, esph->hashsize);
esph->Final(buf2, &ctx);
if (bcmp(buf2, buf, AH_HMAC_HASHLEN))
{
DPRINTF(("esp_new_input(): authentication failed for packet from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi)));
espstat.esps_badauth++;
m_freem(m);
return NULL;
}
}
oplen = plen;
ilen = m->m_len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t);
idat = mtod(m, unsigned char *) + (ip->ip_hl << 2) + 2 * sizeof(u_int32_t);
bcopy(idat, iv, tdb->tdb_ivlen);
ilen -= tdb->tdb_ivlen;
idat += tdb->tdb_ivlen;
mi = m;
/*
* At this point:
* plen is # of encapsulated payload octets
* ilen is # of octets left in this mbuf
* idat is first encapsulated payload octed in this mbuf
* same for olen and odat
* ivp points to the IV, ivn buffers the next IV.
* mi points to the first mbuf
*
* From now on until the end of the mbuf chain:
* . move the next eight octets of the chain into ivn
* . decrypt idat and xor with ivp
* . swap ivp and ivn.
* . repeat
*/
ivp = iv;
ivn = niv;
rest = ilen % blks;
while (plen > 0) /* while not done */
{
if (ilen < blks)
{
if (rest)
{
bcopy(idat, blk, rest);
odat = idat;
}
do {
mi = (mo = mi)->m_next;
if (mi == NULL)
{
DPRINTF(("esp_new_input(): bad mbuf chain, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_hdrops++;
m_freem(m);
return NULL;
}
} while (mi->m_len == 0);
if (mi->m_len < blks - rest)
{
if ((mi = m_pullup(mi, blks - rest)) == NULL)
{
DPRINTF(("esp_new_input(): m_pullup() failed, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_hdrops++;
return NULL;
}
/*
* m_pullup was not called at the beginning of the chain
* but might return a new mbuf, link it into the chain.
*/
mo->m_next = mi;
}
ilen = mi->m_len;
idat = mtod(mi, u_char *);
if (rest)
{
bcopy(idat, blk + rest, blks - rest);
bcopy(blk, ivn, blks);
espx->decrypt(tdb, blk);
for (i = 0; i < blks; i++)
blk[i] ^= ivp[i];
ivp = ivn;
ivn = (ivp == iv) ? niv : iv;
bcopy(blk, odat, rest);
bcopy(blk + rest, idat, blks - rest);
lblk = blk; /* last block touched */
idat += blks - rest;
ilen -= blks - rest;
plen -= blks;
}
rest = ilen % blks;
}
while (ilen >= blks && plen > 0)
{
bcopy(idat, ivn, blks);
espx->decrypt(tdb, idat);
for (i = 0; i < blks; i++)
idat[i] ^= ivp[i];
ivp = ivn;
ivn = (ivp == iv) ? niv : iv;
lblk = idat; /* last block touched */
idat += blks;
ilen -= blks;
plen -= blks;
}
}
/* Save the options */
m_copydata(m, sizeof(struct ip), (ipo.ip_hl << 2) - sizeof(struct ip),
(caddr_t) opts);
if (lblk != blk)
bcopy(lblk, blk, blks);
/*
* Now, the entire chain has been decrypted. As a side effect,
* blk[blks - 1] contains the next protocol, and blk[blks - 2] contains
* the amount of padding the original chain had. Chop off the
* appropriate parts of the chain, and return.
* Verify correct decryption by checking the last padding bytes.
*/
if (blk[blks - 2] + 2 + alen > m->m_pkthdr.len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t) - tdb->tdb_ivlen)
{
DPRINTF(("esp_new_input(): invalid padding length %d for packet from %s to %s, spi %08x\n", blk[blks - 2], inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi)));
espstat.esps_badilen++;
m_freem(m);
return NULL;
}
if ((blk[blks - 2] != blk[blks - 3]) && (blk[blks - 2] != 0))
{
DPRINTF(("esp_new_input(): decryption failed for packet from %s to %s, spi %08x\n", inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
return NULL;
}
m_adj(m, - blk[blks - 2] - 2 - alen); /* Old type padding */
m_adj(m, 2 * sizeof(u_int32_t) + tdb->tdb_ivlen);
if (m->m_len < (ipo.ip_hl << 2))
{
m = m_pullup(m, (ipo.ip_hl << 2));
if (m == NULL)
{
DPRINTF(("esp_new_input(): m_pullup() failed for packet from %s to %s, spi %08x\n", inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi)));
espstat.esps_hdrops++;
return NULL;
}
}
ip = mtod(m, struct ip *);
ipo.ip_p = blk[blks - 1];
ipo.ip_id = htons(ipo.ip_id);
ipo.ip_off = 0;
ipo.ip_len += (ipo.ip_hl << 2) - 2 * sizeof(u_int32_t) - tdb->tdb_ivlen -
blk[blks - 2] - 2 - alen;
ipo.ip_len = htons(ipo.ip_len);
ipo.ip_sum = 0;
*ip = ipo;
/* Copy the options back */
m_copyback(m, sizeof(struct ip), (ipo.ip_hl << 2) - sizeof(struct ip),
(caddr_t) opts);
ip->ip_sum = in_cksum(m, (ip->ip_hl << 2));
return m;
}
int
esp_new_output(struct mbuf *m, struct sockaddr_encap *gw, struct tdb *tdb,
struct mbuf **mp)
{
struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform;
struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform;
struct ip *ip, ipo;
int i, ilen, ohlen, nh, rlen, plen, padding, rest;
struct esp_new espo;
struct mbuf *mi, *mo;
u_char *pad, *idat, *odat, *ivp;
u_char iv[ESP_MAX_IVS], blk[ESP_MAX_BLKS], auth[AH_ALEN_MAX], opts[40];
union {
MD5_CTX md5ctx;
SHA1_CTX sha1ctx;
RMD160_CTX rmd160ctx;
} ctx;
int iphlen, blks, alen;
blks = espx->blocksize;
if (esph)
alen = AH_HMAC_HASHLEN;
else
alen = 0;
espstat.esps_output++;
m = m_pullup(m, sizeof (struct ip)); /* Get IP header in one mbuf */
if (m == NULL)
{
DPRINTF(("esp_new_output(): m_pullup() failed, SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_hdrops++;
return ENOBUFS;
}
if (tdb->tdb_rpl == 0)
{
DPRINTF(("esp_new_output(): SA %s/%0x8 should have expired\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_wrap++;
return ENOBUFS;
}
espo.esp_spi = tdb->tdb_spi;
espo.esp_rpl = htonl(tdb->tdb_rpl++);
ip = mtod(m, struct ip *);
iphlen = (ip->ip_hl << 2);
/* Update the counters */
tdb->tdb_cur_bytes += ntohs(ip->ip_len) - (ip->ip_hl << 2);
espstat.esps_obytes += ntohs(ip->ip_len) - (ip->ip_hl << 2);
/* Hard expiration */
if ((tdb->tdb_flags & TDBF_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes))
{
/* XXX
encap_sendnotify(NOTIFY_HARD_EXPIRE, tdb, NULL);
*/
tdb_delete(tdb, 0);
m_freem(m);
return EINVAL;
}
/* Notify on expiration */
if ((tdb->tdb_flags & TDBF_SOFT_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes))
{
/* XXX
encap_sendnotify(NOTIFY_SOFT_EXPIRE, tdb, NULL);
*/
tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */
}
/*
* If options are present, pullup the IP header, the options.
*/
if (iphlen != sizeof(struct ip))
{
m = m_pullup(m, iphlen + 8);
if (m == NULL)
{
DPRINTF(("esp_new_input(): m_pullup() failed for SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_hdrops++;
return ENOBUFS;
}
ip = mtod(m, struct ip *);
/* Keep the options */
m_copydata(m, sizeof(struct ip), iphlen - sizeof(struct ip),
(caddr_t) opts);
}
ilen = ntohs(ip->ip_len); /* Size of the packet */
ohlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen;
ipo = *ip;
nh = ipo.ip_p;
/* Raw payload length */
rlen = ilen - iphlen;
padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
if (iphlen + ohlen + rlen + padding + alen > IP_MAXPACKET)
{
DPRINTF(("esp_new_output(): packet in SA %s/%0x8 got too big\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_toobig++;
return EMSGSIZE;
}
pad = (u_char *) m_pad(m, padding + alen, 0);
if (pad == NULL)
{
DPRINTF(("esp_new_output(): m_pad() failed for SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
return ENOBUFS;
}
/* Self describing padding */
for (i = 0; i < padding - 2; i++)
pad[i] = i + 1;
pad[padding - 2] = padding - 2;
pad[padding - 1] = nh;
mi = m;
plen = rlen + padding;
ilen = m->m_len - iphlen;
idat = mtod(m, u_char *) + iphlen;
bcopy(tdb->tdb_iv, iv, tdb->tdb_ivlen);
bcopy(tdb->tdb_iv, espo.esp_iv, tdb->tdb_ivlen);
/* Authenticate the esp header */
if (esph)
{
bcopy(tdb->tdb_ictx, &ctx, esph->ctxsize);
esph->Update(&ctx, (unsigned char *) &espo,
2 * sizeof(u_int32_t) + tdb->tdb_ivlen);
}
/* Encrypt the payload */
ivp = iv;
rest = ilen % blks;
while (plen > 0) /* while not done */
{
if (ilen < blks)
{
if (rest)
{
if (ivp == blk)
{
bcopy(blk, iv, blks);
ivp = iv;
}
bcopy(idat, blk, rest);
odat = idat;
}
do {
mi = (mo = mi)->m_next;
if (mi == NULL)
{
DPRINTF(("esp_new_output(): bad mbuf chain, SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_hdrops++;
m_freem(m);
return EINVAL;
}
} while (mi->m_len == 0);
if (mi->m_len < blks - rest)
{
if ((mi = m_pullup(mi, blks - rest)) == NULL)
{
DPRINTF(("esp_new_output(): m_pullup() failed, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_hdrops++;
return ENOBUFS;
}
/*
* m_pullup was not called at the beginning of the chain
* but might return a new mbuf, link it into the chain.
*/
mo->m_next = mi;
}
ilen = mi->m_len;
idat = mtod(mi, u_char *);
if (rest)
{
bcopy(idat, blk + rest, blks - rest);
for (i = 0; i < blks; i++)
blk[i] ^= ivp[i];
espx->encrypt(tdb, blk);
if (esph)
esph->Update(&ctx, blk, blks);
ivp = blk;
bcopy(blk, odat, rest);
bcopy(blk + rest, idat, blks - rest);
idat += blks - rest;
ilen -= blks - rest;
plen -= blks;
}
rest = ilen % blks;
}
while (ilen >= blks && plen > 0)
{
for (i = 0; i < blks; i++)
idat[i] ^= ivp[i];
espx->encrypt(tdb, idat);
if (esph)
esph->Update(&ctx, idat, blks);
ivp = idat;
idat += blks;
ilen -= blks;
plen -= blks;
}
}
/* Put in authentication data */
if (esph)
{
esph->Final(auth, &ctx);
bcopy(tdb->tdb_octx, &ctx, esph->ctxsize);
esph->Update(&ctx, auth, esph->hashsize);
esph->Final(auth, &ctx);
/* Copy the final authenticator */
bcopy(auth, pad + padding, alen);
}
/*
* Done with encryption. Let's wedge in the ESP header
* and send it out.
*/
M_PREPEND(m, ohlen, M_DONTWAIT);
if (m == NULL)
{
DPRINTF(("esp_new_output(): M_PREPEND failed, SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
return ENOBUFS;
}
m = m_pullup(m, iphlen + ohlen);
if (m == NULL)
{
DPRINTF(("esp_new_output(): m_pullup() failed, SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_hdrops++;
return ENOBUFS;
}
/* Fix the length and the next protocol, copy back and off we go */
ipo.ip_len = htons(iphlen + ohlen + rlen + padding + alen);
ipo.ip_p = IPPROTO_ESP;
/* Save the last encrypted block, to be used as the next IV */
bcopy(ivp, tdb->tdb_iv, tdb->tdb_ivlen);
m_copyback(m, 0, sizeof(struct ip), (caddr_t) &ipo);
/* Copy options, if existing */
if (iphlen != sizeof(struct ip))
m_copyback(m, sizeof(struct ip), iphlen - sizeof(struct ip),
(caddr_t) opts);
/* Copy in the esp header */
m_copyback(m, iphlen, ohlen, (caddr_t) &espo);
*mp = m;
return 0;
}
/*
* return 0 on success
* return 1 for counter == 0
* return 2 for very old packet
* return 3 for packet within current window but already received
*/
int
checkreplaywindow32(u_int32_t seq, u_int32_t initial, u_int32_t *lastseq,
u_int32_t window, u_int32_t *bitmap)
{
u_int32_t diff;
seq -= initial;
if (seq == 0)
return 1;
if (seq > *lastseq - initial)
{
diff = seq - (*lastseq - initial);
if (diff < window)
*bitmap = ((*bitmap) << diff) | 1;
else
*bitmap = 1;
*lastseq = seq + initial;
return 0;
}
diff = *lastseq - initial - seq;
if (diff >= window)
{
espstat.esps_wrap++;
return 2;
}
if ((*bitmap) & (((u_int32_t) 1) << diff))
{
espstat.esps_replay++;
return 3;
}
*bitmap |= (((u_int32_t) 1) << diff);
return 0;
}
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