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|
/* $OpenBSD: ip_esp.c,v 1.66 2001/06/13 13:42:02 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).
*
* The original version of 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.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/bpf.h>
#include <dev/rndvar.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#endif /* INET */
#ifdef INET6
#ifndef INET
#include <netinet/in.h>
#endif
#include <netinet/ip6.h>
#endif /* INET6 */
#include <netinet/ip_ipsp.h>
#include <netinet/ip_esp.h>
#include <net/pfkeyv2.h>
#include <net/if_enc.h>
#include <crypto/crypto.h>
#include <crypto/xform.h>
#include "bpfilter.h"
#ifdef ENCDEBUG
#define DPRINTF(x) if (encdebug) printf x
#else
#define DPRINTF(x)
#endif
/*
* esp_attach() is called from the transformation initialization code.
*/
int
esp_attach()
{
return 0;
}
/*
* esp_init() is called when an SPI is being set up.
*/
int
esp_init(struct tdb *tdbp, struct xformsw *xsp, struct ipsecinit *ii)
{
struct enc_xform *txform = NULL;
struct auth_hash *thash = NULL;
struct cryptoini cria, crie;
if (ii->ii_encalg)
{
switch (ii->ii_encalg)
{
case SADB_EALG_DESCBC:
txform = &enc_xform_des;
break;
case SADB_EALG_3DESCBC:
txform = &enc_xform_3des;
break;
case SADB_X_EALG_AES:
txform = &enc_xform_rijndael128;
break;
case SADB_X_EALG_BLF:
txform = &enc_xform_blf;
break;
case SADB_X_EALG_CAST:
txform = &enc_xform_cast5;
break;
case SADB_X_EALG_SKIPJACK:
txform = &enc_xform_skipjack;
break;
default:
DPRINTF(("esp_init(): unsupported encryption algorithm %d specified\n", ii->ii_encalg));
return EINVAL;
}
if (ii->ii_enckeylen < txform->minkey)
{
DPRINTF(("esp_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_init(): keylength %d too large (max length is %d) for algorithm %s\n", ii->ii_enckeylen, txform->maxkey, txform->name));
return EINVAL;
}
tdbp->tdb_encalgxform = txform;
DPRINTF(("esp_init(): initialized TDB with enc algorithm %s\n",
txform->name));
tdbp->tdb_ivlen = txform->blocksize;
if (tdbp->tdb_flags & TDBF_HALFIV)
tdbp->tdb_ivlen /= 2;
}
if (ii->ii_authalg)
{
switch (ii->ii_authalg)
{
case SADB_AALG_MD5HMAC:
thash = &auth_hash_hmac_md5_96;
break;
case SADB_AALG_SHA1HMAC:
thash = &auth_hash_hmac_sha1_96;
break;
case SADB_AALG_RIPEMD160HMAC:
thash = &auth_hash_hmac_ripemd_160_96;
break;
default:
DPRINTF(("esp_init(): unsupported authentication algorithm %d specified\n", ii->ii_authalg));
return EINVAL;
}
if (ii->ii_authkeylen != thash->keysize)
{
DPRINTF(("esp_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_init(): initialized TDB with hash algorithm %s\n",
thash->name));
}
tdbp->tdb_xform = xsp;
tdbp->tdb_bitmap = 0;
tdbp->tdb_rpl = AH_HMAC_INITIAL_RPL;
/* Initialize crypto session */
if (tdbp->tdb_encalgxform)
{
/* Save the raw keys */
tdbp->tdb_emxkeylen = ii->ii_enckeylen;
MALLOC(tdbp->tdb_emxkey, u_int8_t *, tdbp->tdb_emxkeylen, M_XDATA,
M_WAITOK);
bcopy(ii->ii_enckey, tdbp->tdb_emxkey, tdbp->tdb_emxkeylen);
bzero(&crie, sizeof(crie));
crie.cri_alg = tdbp->tdb_encalgxform->type;
if (tdbp->tdb_authalgxform)
crie.cri_next = &cria;
else
crie.cri_next = NULL;
crie.cri_klen = ii->ii_enckeylen * 8;
crie.cri_key = ii->ii_enckey;
/* XXX Rounds ? */
}
if (tdbp->tdb_authalgxform)
{
/* Save the raw keys */
tdbp->tdb_amxkeylen = ii->ii_authkeylen;
MALLOC(tdbp->tdb_amxkey, u_int8_t *, tdbp->tdb_amxkeylen, M_XDATA,
M_WAITOK);
bcopy(ii->ii_authkey, tdbp->tdb_amxkey, tdbp->tdb_amxkeylen);
bzero(&cria, sizeof(cria));
cria.cri_alg = tdbp->tdb_authalgxform->type;
cria.cri_next = NULL;
cria.cri_klen = ii->ii_authkeylen * 8;
cria.cri_key = ii->ii_authkey;
}
return crypto_newsession(&tdbp->tdb_cryptoid,
(tdbp->tdb_encalgxform ? &crie : &cria), 0);
}
/*
* Paranoia.
*/
int
esp_zeroize(struct tdb *tdbp)
{
int err;
if (tdbp->tdb_amxkey)
{
bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen);
FREE(tdbp->tdb_amxkey, M_XDATA);
tdbp->tdb_amxkey = NULL;
}
if (tdbp->tdb_emxkey)
{
bzero(tdbp->tdb_emxkey, tdbp->tdb_emxkeylen);
FREE(tdbp->tdb_emxkey, M_XDATA);
tdbp->tdb_emxkey = NULL;
}
err = crypto_freesession(tdbp->tdb_cryptoid);
tdbp->tdb_cryptoid = 0;
return err;
}
#define MAXBUFSIZ (AH_ALEN_MAX > ESP_MAX_IVS ? AH_ALEN_MAX : ESP_MAX_IVS)
/*
* ESP input processing, called (eventually) through the protocol switch.
*/
int
esp_input(struct mbuf *m, struct tdb *tdb, int skip, int protoff)
{
struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform;
struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform;
struct tdb_ident *tdbi;
struct tdb_crypto *tc;
int plen, alen, hlen;
struct m_tag *mtag;
u_int32_t btsx;
struct cryptodesc *crde = NULL, *crda = NULL;
struct cryptop *crp;
/* Determine the ESP header length */
if (tdb->tdb_flags & TDBF_NOREPLAY)
hlen = sizeof(u_int32_t) + tdb->tdb_ivlen; /* "old" ESP */
else
hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; /* "new" ESP */
if (esph)
alen = AH_HMAC_HASHLEN;
else
alen = 0;
if (espx)
{
/*
* Verify payload length is multiple of encryption algorithm
* block size.
*/
plen = m->m_pkthdr.len - (skip + hlen + alen);
if ((plen & (espx->blocksize - 1)) || (plen <= 0))
{
DPRINTF(("esp_input(): payload of %d octets not a multiple of %d octets, SA %s/%08x\n", plen, espx->blocksize, ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_badilen++;
m_freem(m);
return EINVAL;
}
}
/* Replay window checking, if appropriate */
if ((tdb->tdb_wnd > 0) && (!(tdb->tdb_flags & TDBF_NOREPLAY)))
{
m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
(unsigned char *) &btsx);
btsx = ntohl(btsx);
switch (checkreplaywindow32(btsx, 0, &(tdb->tdb_rpl), tdb->tdb_wnd,
&(tdb->tdb_bitmap)))
{
case 0: /* All's well */
break;
case 1:
DPRINTF(("esp_input(): replay counter wrapped for SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_wrap++;
m_freem(m);
return EACCES;
case 2:
case 3:
DPRINTF(("esp_input(): duplicate packet received in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_replay++;
m_freem(m);
return EACCES;
default:
DPRINTF(("esp_input(): bogus value from checkreplaywindow32() in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_replay++;
m_freem(m);
return EACCES;
}
}
/* Update the counters */
tdb->tdb_cur_bytes += m->m_pkthdr.len - skip - hlen - alen;
espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen;
/* Hard expiration */
if ((tdb->tdb_flags & TDBF_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes))
{
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD);
tdb_delete(tdb);
m_freem(m);
return ENXIO;
}
/* Notify on soft expiration */
if ((tdb->tdb_flags & TDBF_SOFT_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes))
{
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT);
tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */
}
/* Find out if we've already done crypto */
for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
mtag != NULL;
mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag))
{
tdbi = (struct tdb_ident *) (mtag + 1);
if (tdbi->proto == tdb->tdb_sproto && tdbi->spi == tdb->tdb_spi &&
!bcmp(&tdbi->dst, &tdb->tdb_dst, sizeof(union sockaddr_union)))
break;
}
/* Get crypto descriptors */
crp = crypto_getreq(esph && espx ? 2 : 1);
if (crp == NULL)
{
m_freem(m);
DPRINTF(("esp_input(): failed to acquire crypto descriptors\n"));
espstat.esps_crypto++;
return ENOBUFS;
}
/* Get IPsec-specific opaque pointer */
if (esph == NULL || mtag != NULL)
MALLOC(tc, struct tdb_crypto *, sizeof(struct tdb_crypto),
M_XDATA, M_NOWAIT);
else
MALLOC(tc, struct tdb_crypto *, sizeof(struct tdb_crypto) + alen,
M_XDATA, M_NOWAIT);
if (tc == NULL)
{
m_freem(m);
crypto_freereq(crp);
DPRINTF(("esp_input(): failed to allocate tdb_crypto\n"));
espstat.esps_crypto++;
return ENOBUFS;
}
bzero(tc, sizeof(struct tdb_crypto));
tc->tc_ptr = (caddr_t) mtag;
if (esph)
{
crda = crp->crp_desc;
crde = crda->crd_next;
/* Authentication descriptor */
crda->crd_skip = skip;
crda->crd_len = m->m_pkthdr.len - (skip + alen);
crda->crd_inject = m->m_pkthdr.len - alen;
crda->crd_alg = esph->type;
crda->crd_key = tdb->tdb_amxkey;
crda->crd_klen = tdb->tdb_amxkeylen * 8;
/* Copy the authenticator */
if (mtag == NULL)
m_copydata(m, m->m_pkthdr.len - alen, alen, (caddr_t) (tc + 1));
}
else
crde = crp->crp_desc;
/* Crypto operation descriptor */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
crp->crp_flags = CRYPTO_F_IMBUF;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = (int (*) (struct cryptop *)) esp_input_cb;
crp->crp_sid = tdb->tdb_cryptoid;
crp->crp_opaque = (caddr_t) tc;
/* These are passed as-is to the callback */
tc->tc_skip = skip;
tc->tc_protoff = protoff;
tc->tc_spi = tdb->tdb_spi;
tc->tc_proto = tdb->tdb_sproto;
bcopy(&tdb->tdb_dst, &tc->tc_dst, sizeof(union sockaddr_union));
/* Decryption descriptor */
if (espx)
{
crde->crd_skip = skip + hlen;
crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
crde->crd_inject = skip + hlen - tdb->tdb_ivlen;
if (tdb->tdb_flags & TDBF_HALFIV)
{
/* Copy half-IV from packet */
m_copydata(m, crde->crd_inject, tdb->tdb_ivlen, crde->crd_iv);
/* Cook IV */
for (btsx = 0; btsx < tdb->tdb_ivlen; btsx++)
crde->crd_iv[tdb->tdb_ivlen + btsx] = ~crde->crd_iv[btsx];
crde->crd_flags |= CRD_F_IV_EXPLICIT;
}
crde->crd_alg = espx->type;
crde->crd_key = tdb->tdb_emxkey;
crde->crd_klen = tdb->tdb_emxkeylen * 8;
/* XXX Rounds ? */
}
if (mtag == NULL)
return crypto_dispatch(crp);
else
return esp_input_cb(crp);
}
/*
* ESP input callback, called directly by the crypto driver.
*/
int
esp_input_cb(void *op)
{
u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
int hlen, roff, skip, protoff, error;
struct mbuf *m1, *mo, *m;
struct cryptodesc *crd;
struct auth_hash *esph;
struct enc_xform *espx;
struct tdb_crypto *tc;
struct cryptop *crp;
struct m_tag *mtag;
struct tdb *tdb;
int s, err = 0;
caddr_t ptr;
crp = (struct cryptop *) op;
crd = crp->crp_desc;
tc = (struct tdb_crypto *) crp->crp_opaque;
skip = tc->tc_skip;
protoff = tc->tc_protoff;
mtag = (struct m_tag *) tc->tc_ptr;
m = (struct mbuf *) crp->crp_buf;
s = spltdb();
tdb = gettdb(tc->tc_spi, &tc->tc_dst, tc->tc_proto);
FREE(tc, M_XDATA);
if (tdb == NULL)
{
espstat.esps_notdb++;
DPRINTF(("esp_input_cb(): TDB is expired while in crypto"));
goto baddone;
}
esph = (struct auth_hash *) tdb->tdb_authalgxform;
espx = (struct enc_xform *) tdb->tdb_encalgxform;
/* Check for crypto errors */
if (crp->crp_etype)
{
/* Reset the session ID */
if (tdb->tdb_cryptoid != 0)
tdb->tdb_cryptoid = crp->crp_sid;
if (crp->crp_etype == EAGAIN)
{
splx(s);
return crypto_dispatch(crp);
}
espstat.esps_noxform++;
DPRINTF(("esp_input_cb(): crypto error %d\n", crp->crp_etype));
error = crp->crp_etype;
goto baddone;
}
/* Shouldn't happen... */
if (m == NULL)
{
espstat.esps_crypto++;
DPRINTF(("esp_input_cb(): bogus returned buffer from crypto\n"));
error = EINVAL;
goto baddone;
}
/* If authentication was performed, check now. */
if (esph != NULL)
{
/*
* If we have a tag, it means an IPsec-aware NIC did the verification
* for us.
*/
if (mtag != NULL)
{
/* Copy the authenticator from the packet */
m_copydata(m, m->m_pkthdr.len - esph->authsize, esph->authsize,
aalg);
ptr = (caddr_t) (tc + 1);
/* Verify authenticator */
if (bcmp(ptr, aalg, esph->authsize))
{
DPRINTF(("esp_input_cb(): authentication failed for packet in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_badauth++;
error = EACCES;
goto baddone;
}
}
/* Remove trailing authenticator */
m_adj(m, -(esph->authsize));
}
/* Release the crypto descriptors */
crypto_freereq(crp);
/* Determine the ESP header length */
if (tdb->tdb_flags & TDBF_NOREPLAY)
hlen = sizeof(u_int32_t) + tdb->tdb_ivlen; /* "old" ESP */
else
hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; /* "new" ESP */
/* Find beginning of ESP header */
m1 = m_getptr(m, skip, &roff);
if (m1 == NULL)
{
espstat.esps_hdrops++;
splx(s);
DPRINTF(("esp_input_cb(): bad mbuf chain, SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
return EINVAL;
}
/* Remove the ESP header and IV from the mbuf. */
if (roff == 0)
{
/* The ESP header was conveniently at the beginning of the mbuf */
m_adj(m1, hlen);
if (!(m1->m_flags & M_PKTHDR))
m->m_pkthdr.len -= hlen;
}
else
if (roff + hlen >= m1->m_len)
{
/*
* Part or all of the ESP header is at the end of this mbuf, so
* first let's remove the remainder of the ESP header from the
* beginning of the remainder of the mbuf chain, if any.
*/
if (roff + hlen > m1->m_len)
{
/* Adjust the next mbuf by the remainder */
m_adj(m1->m_next, roff + hlen - m1->m_len);
/* The second mbuf is guaranteed not to have a pkthdr... */
m->m_pkthdr.len -= (roff + hlen - m1->m_len);
}
/* Now, let's unlink the mbuf chain for a second...*/
mo = m1->m_next;
m1->m_next = NULL;
/* ...and trim the end of the first part of the chain...sick */
m_adj(m1, -(m1->m_len - roff));
if (!(m1->m_flags & M_PKTHDR))
m->m_pkthdr.len -= (m1->m_len - roff);
/* Finally, let's relink */
m1->m_next = mo;
}
else
{
/*
* The ESP header lies in the "middle" of the mbuf...do an
* overlapping copy of the remainder of the mbuf over the ESP
* header.
*/
bcopy(mtod(m1, u_char *) + roff + hlen, mtod(m1, u_char *) + roff,
m1->m_len - (roff + hlen));
m1->m_len -= hlen;
m->m_pkthdr.len -= hlen;
}
/* Save the last three bytes of decrypted data */
m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
/* Verify pad length */
if (lastthree[1] + 2 > m->m_pkthdr.len - skip)
{
espstat.esps_badilen++;
splx(s);
DPRINTF(("esp_input_cb(): invalid padding length %d for packet in SA %s/%08x\n", lastthree[1], ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
return EINVAL;
}
/* Verify correct decryption by checking the last padding bytes */
if (!(tdb->tdb_flags & TDBF_RANDOMPADDING))
{
if ((lastthree[1] != lastthree[0]) && (lastthree[1] != 0))
{
espstat.esps_badenc++;
splx(s);
DPRINTF(("esp_input(): decryption failed for packet in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
return EINVAL;
}
}
/* Trim the mbuf chain to remove the trailing authenticator and padding */
m_adj(m, -(lastthree[1] + 2));
/* Restore the Next Protocol field */
m_copyback(m, protoff, sizeof(u_int8_t), lastthree + 2);
/* Back to generic IPsec input processing */
err = ipsec_common_input_cb(m, tdb, skip, protoff, mtag);
splx(s);
return err;
baddone:
splx(s);
if (m)
m_freem(m);
crypto_freereq(crp);
return error;
}
/*
* ESP output routine, called by ipsp_process_packet().
*/
int
esp_output(struct mbuf *m, struct tdb *tdb, struct mbuf **mp, int skip,
int protoff)
{
struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform;
struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform;
int ilen, hlen, rlen, plen, padding, blks, alen;
struct mbuf *mi, *mo = (struct mbuf *) NULL;
struct tdb_crypto *tc;
unsigned char *pad;
u_int8_t prot;
struct cryptodesc *crde = NULL, *crda = NULL;
struct cryptop *crp;
#if NBPFILTER > 0
{
struct ifnet *ifn;
struct enchdr hdr;
struct mbuf m1;
bzero (&hdr, sizeof(hdr));
hdr.af = tdb->tdb_dst.sa.sa_family;
hdr.spi = tdb->tdb_spi;
if (espx)
hdr.flags |= M_CONF;
if (esph)
hdr.flags |= M_AUTH;
m1.m_next = m;
m1.m_len = ENC_HDRLEN;
m1.m_data = (char *) &hdr;
ifn = &(encif[0].sc_if);
if (ifn->if_bpf)
bpf_mtap(ifn->if_bpf, &m1);
}
#endif
if (tdb->tdb_flags & TDBF_NOREPLAY)
hlen = sizeof(u_int32_t) + tdb->tdb_ivlen;
else
hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen;
rlen = m->m_pkthdr.len - skip; /* Raw payload length */
if (espx)
blks = espx->blocksize;
else
blks = 4; /* If no encryption is used, we have to be 4-byte aligned */
padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
plen = rlen + padding; /* Padded payload length */
if (esph)
alen = AH_HMAC_HASHLEN;
else
alen = 0;
espstat.esps_output++;
/* Check for replay counter wrap-around in automatic (not manual) keying */
if ((!(tdb->tdb_flags & TDBF_NOREPLAY)) &&
(tdb->tdb_rpl == 0) && (tdb->tdb_wnd > 0))
{
DPRINTF(("esp_output(): SA %s/%08x should have expired\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_wrap++;
return EACCES;
}
switch (tdb->tdb_dst.sa.sa_family)
{
#ifdef INET
case AF_INET:
/* Check for IP maximum packet size violations */
if (skip + hlen + rlen + padding + alen > IP_MAXPACKET)
{
DPRINTF(("esp_output(): packet in SA %s/%08x got too big\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_toobig++;
return EMSGSIZE;
}
break;
#endif /* INET */
#ifdef INET6
case AF_INET6:
/* Check for IPv6 maximum packet size violations */
if (skip + hlen + rlen + padding + alen > IPV6_MAXPACKET)
{
DPRINTF(("esp_output(): packet in SA %s/%08x got too big\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_toobig++;
return EMSGSIZE;
}
break;
#endif /* INET6 */
default:
DPRINTF(("esp_output(): unknown/unsupported protocol family %d, SA %s/%08x\n", tdb->tdb_dst.sa.sa_family, ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_nopf++;
return EPFNOSUPPORT;
}
/* Update the counters */
tdb->tdb_cur_bytes += m->m_pkthdr.len - skip;
espstat.esps_obytes += m->m_pkthdr.len - skip;
/* Hard byte expiration */
if ((tdb->tdb_flags & TDBF_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes))
{
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD);
tdb_delete(tdb);
m_freem(m);
return EINVAL;
}
/* Soft byte expiration */
if ((tdb->tdb_flags & TDBF_SOFT_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes))
{
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT);
tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */
}
/*
* Loop through mbuf chain; if we find an M_EXT mbuf with
* more than one reference, replace the rest of the chain.
*/
mi = m;
while (mi != NULL &&
(!(mi->m_flags & M_EXT) || !MCLISREFERENCED(mi)))
{
mo = mi;
mi = mi->m_next;
}
if (mi != NULL)
{
/* Replace the rest of the mbuf chain. */
struct mbuf *n = m_copym2(mi, 0, M_COPYALL, M_DONTWAIT);
if (n == NULL)
{
DPRINTF(("esp_output(): bad mbuf chain, SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
espstat.esps_hdrops++;
m_freem(m);
return ENOBUFS;
}
if (mo != NULL)
mo->m_next = n;
else
m = n;
m_freem(mi);
}
/* Inject ESP header */
mo = m_inject(m, skip, hlen, M_DONTWAIT);
if (mo == NULL)
{
DPRINTF(("esp_output(): failed to inject ESP header for SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
m_freem(m);
espstat.esps_wrap++;
return ENOBUFS;
}
/* Initialize ESP header */
bcopy((caddr_t) &tdb->tdb_spi, mtod(mo, caddr_t), sizeof(u_int32_t));
if (!(tdb->tdb_flags & TDBF_NOREPLAY))
{
u_int32_t replay = htonl(tdb->tdb_rpl++);
bcopy((caddr_t) &replay, mtod(mo, caddr_t) + sizeof(u_int32_t),
sizeof(u_int32_t));
}
/*
* Add padding -- better to do it ourselves than use the crypto engine,
* although if/when we support compression, we'd have to do that.
*/
pad = (u_char *) m_pad(m, padding + alen);
if (pad == NULL)
{
DPRINTF(("esp_output(): m_pad() failed for SA %s/%08x\n",
ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi)));
return ENOBUFS;
}
/* Self-describing padding ? */
if (!(tdb->tdb_flags & TDBF_RANDOMPADDING))
for (ilen = 0; ilen < padding - 2; ilen++)
pad[ilen] = ilen + 1;
else
get_random_bytes((void *) pad, padding - 2); /* Random padding */
/* Fix padding length and Next Protocol in padding itself */
pad[padding - 2] = padding - 2;
m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
/* Fix Next Protocol in IPv4/IPv6 header */
prot = IPPROTO_ESP;
m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
/* Get crypto descriptors */
crp = crypto_getreq(esph && espx ? 2 : 1);
if (crp == NULL)
{
m_freem(m);
DPRINTF(("esp_output(): failed to acquire crypto descriptors\n"));
espstat.esps_crypto++;
return ENOBUFS;
}
if (espx)
{
crde = crp->crp_desc;
crda = crde->crd_next;
/* Encryption descriptor */
crde->crd_skip = skip + hlen;
crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
crde->crd_flags = CRD_F_ENCRYPT;
crde->crd_inject = skip + hlen - tdb->tdb_ivlen;
if (tdb->tdb_flags & TDBF_HALFIV)
{
/* Copy half-iv in the packet */
m_copyback(m, crde->crd_inject, tdb->tdb_ivlen, tdb->tdb_iv);
/* Cook half-iv */
bcopy(tdb->tdb_iv, crde->crd_iv, tdb->tdb_ivlen);
for (ilen = 0; ilen < tdb->tdb_ivlen; ilen++)
crde->crd_iv[tdb->tdb_ivlen + ilen] = ~crde->crd_iv[ilen];
crde->crd_flags |= CRD_F_IV_PRESENT | CRD_F_IV_EXPLICIT;
}
/* Encryption operation */
crde->crd_alg = espx->type;
crde->crd_key = tdb->tdb_emxkey;
crde->crd_klen = tdb->tdb_emxkeylen * 8;
/* XXX Rounds ? */
}
else
crda = crp->crp_desc;
/* IPsec-specific opaque crypto info */
MALLOC(tc, struct tdb_crypto *, sizeof(struct tdb_crypto),
M_XDATA, M_NOWAIT);
if (tc == NULL)
{
m_freem(m);
crypto_freereq(crp);
DPRINTF(("esp_output(): failed to allocate tdb_crypto\n"));
espstat.esps_crypto++;
return ENOBUFS;
}
bzero(tc, sizeof(struct tdb_crypto));
tc->tc_spi = tdb->tdb_spi;
tc->tc_proto = tdb->tdb_sproto;
bcopy(&tdb->tdb_dst, &tc->tc_dst, sizeof(union sockaddr_union));
/* Crypto operation descriptor */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
crp->crp_flags = CRYPTO_F_IMBUF;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = (int (*) (struct cryptop *)) esp_output_cb;
crp->crp_opaque = (caddr_t) tc;
crp->crp_sid = tdb->tdb_cryptoid;
if (esph)
{
/* Authentication descriptor */
crda->crd_skip = skip;
crda->crd_len = m->m_pkthdr.len - (skip + alen);
crda->crd_inject = m->m_pkthdr.len - alen;
/* Authentication operation */
crda->crd_alg = esph->type;
crda->crd_key = tdb->tdb_amxkey;
crda->crd_klen = tdb->tdb_amxkeylen * 8;
}
if ((tdb->tdb_flags & TDBF_SKIPCRYPTO) == 0)
return crypto_dispatch(crp);
else
return esp_output_cb(crp);
}
/*
* ESP output callback, called directly by the crypto driver.
*/
int
esp_output_cb(void *op)
{
struct cryptop *crp = (struct cryptop *) op;
struct tdb_crypto *tc;
struct tdb *tdb;
struct mbuf *m;
int error, s;
tc = (struct tdb_crypto *) crp->crp_opaque;
m = (struct mbuf *) crp->crp_buf;
s = spltdb();
tdb = gettdb(tc->tc_spi, &tc->tc_dst, tc->tc_proto);
FREE(tc, M_XDATA);
if (tdb == NULL)
{
espstat.esps_notdb++;
DPRINTF(("esp_output_cb(): TDB is expired while in crypto\n"));
goto baddone;
}
/* Check for crypto errors */
if (crp->crp_etype)
{
/* Reset session ID */
if (tdb->tdb_cryptoid != 0)
tdb->tdb_cryptoid = crp->crp_sid;
if (crp->crp_etype == EAGAIN)
{
splx(s);
return crypto_dispatch(crp);
}
espstat.esps_noxform++;
DPRINTF(("esp_output_cb(): crypto error %d\n", crp->crp_etype));
error = crp->crp_etype;
goto baddone;
}
/* Shouldn't happen... */
if (m == NULL)
{
espstat.esps_crypto++;
DPRINTF(("esp_output_cb(): bogus returned buffer from crypto\n"));
error = EINVAL;
goto baddone;
}
/* Release crypto descriptors */
crypto_freereq(crp);
/*
* If we're doing half-iv, keep a copy of the last few bytes of the
* encrypted part, for use as the next IV. Note that HALF-IV is only
* supposed to be used without authentication (the old ESP specs).
*/
if (tdb->tdb_flags & TDBF_HALFIV)
m_copydata(m, m->m_pkthdr.len - tdb->tdb_ivlen, tdb->tdb_ivlen,
tdb->tdb_iv);
/* Call the IPsec input callback */
error = ipsp_process_done(m, tdb);
splx(s);
return error;
baddone:
splx(s);
if (m)
m_freem(m);
crypto_freereq(crp);
return error;
}
/*
* 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;
}
/*
* m_pad(m, n) pads <m> with <n> bytes at the end. The packet header
* length is updated, and a pointer to the first byte of the padding
* (which is guaranteed to be all in one mbuf) is returned.
*/
caddr_t
m_pad(struct mbuf *m, int n)
{
register struct mbuf *m0, *m1;
register int len, pad;
caddr_t retval;
if (n <= 0) /* no stupid arguments */
{
DPRINTF(("m_pad(): pad length invalid (%d)\n", n));
return NULL;
}
len = m->m_pkthdr.len;
pad = n;
m0 = m;
while (m0->m_len < len)
{
len -= m0->m_len;
m0 = m0->m_next;
}
if (m0->m_len != len)
{
DPRINTF(("m_pad(): length mismatch (should be %d instead of %d)\n",
m->m_pkthdr.len, m->m_pkthdr.len + m0->m_len - len));
m_freem(m);
return NULL;
}
/* Check for zero-length trailing mbufs, and find the last one */
for (m1 = m0; m1->m_next; m1 = m1->m_next)
{
if (m1->m_next->m_len != 0)
{
DPRINTF(("m_pad(): length mismatch (should be %d instead of %d)\n",
m->m_pkthdr.len, m->m_pkthdr.len + m1->m_next->m_len));
m_freem(m);
return NULL;
}
m0 = m1->m_next;
}
if ((m0->m_flags & M_EXT) ||
(m0->m_data + m0->m_len + pad >= &(m0->m_dat[MLEN])))
{
/*
* Add an mbuf to the chain
*/
MGET(m1, M_DONTWAIT, MT_DATA);
if (m1 == 0)
{
m_freem(m0);
DPRINTF(("m_pad(): cannot append\n"));
return NULL;
}
m0->m_next = m1;
m0 = m1;
m0->m_len = 0;
}
retval = m0->m_data + m0->m_len;
m0->m_len += pad;
m->m_pkthdr.len += pad;
return retval;
}
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