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src/sys/netinet/ip_esp.c

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/* $OpenBSD: ip_esp.c,v 1.195 2022/05/03 09:18:11 claudio 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.
* Copyright (c) 2001 Angelos D. Keromytis.
*
* Permission to use, copy, and modify this software with or 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 "pfsync.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/bpf.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#ifdef INET6
#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>
#if NPFSYNC > 0
#include <net/pfvar.h>
#include <net/if_pfsync.h>
#endif /* NPFSYNC > 0 */
#include <crypto/cryptodev.h>
#include <crypto/xform.h>
#include "bpfilter.h"
#ifdef ENCDEBUG
#define DPRINTF(fmt, args...) \
do { \
if (encdebug) \
printf("%s: " fmt "\n", __func__, ## args); \
} while (0)
#else
#define DPRINTF(fmt, args...) \
do { } while (0)
#endif
/*
* esp_attach() is called from the transformation initialization code.
*/
int
esp_attach(void)
{
return 0;
}
/*
* esp_init() is called when an SPI is being set up.
*/
int
esp_init(struct tdb *tdbp, const struct xformsw *xsp, struct ipsecinit *ii)
{
const struct enc_xform *txform = NULL;
const struct auth_hash *thash = NULL;
struct cryptoini cria, crie, crin;
int error;
if (!ii->ii_encalg && !ii->ii_authalg) {
DPRINTF("neither authentication nor encryption algorithm "
"given");
return EINVAL;
}
if (ii->ii_encalg) {
switch (ii->ii_encalg) {
case SADB_EALG_NULL:
txform = &enc_xform_null;
break;
case SADB_EALG_3DESCBC:
txform = &enc_xform_3des;
break;
case SADB_X_EALG_AES:
txform = &enc_xform_aes;
break;
case SADB_X_EALG_AESCTR:
txform = &enc_xform_aes_ctr;
break;
case SADB_X_EALG_AESGCM16:
txform = &enc_xform_aes_gcm;
break;
case SADB_X_EALG_AESGMAC:
txform = &enc_xform_aes_gmac;
break;
case SADB_X_EALG_CHACHA20POLY1305:
txform = &enc_xform_chacha20_poly1305;
break;
case SADB_X_EALG_BLF:
txform = &enc_xform_blf;
break;
case SADB_X_EALG_CAST:
txform = &enc_xform_cast5;
break;
default:
DPRINTF("unsupported encryption algorithm %d "
"specified",
ii->ii_encalg);
return EINVAL;
}
if (ii->ii_enckeylen < txform->minkey) {
DPRINTF("keylength %d too small (min length is %d) "
"for algorithm %s",
ii->ii_enckeylen, txform->minkey, txform->name);
return EINVAL;
}
if (ii->ii_enckeylen > txform->maxkey) {
DPRINTF("keylength %d too large (max length is %d) "
"for algorithm %s",
ii->ii_enckeylen, txform->maxkey, txform->name);
return EINVAL;
}
if (ii->ii_encalg == SADB_X_EALG_AESGCM16 ||
ii->ii_encalg == SADB_X_EALG_AESGMAC) {
switch (ii->ii_enckeylen) {
case 20:
ii->ii_authalg = SADB_X_AALG_AES128GMAC;
break;
case 28:
ii->ii_authalg = SADB_X_AALG_AES192GMAC;
break;
case 36:
ii->ii_authalg = SADB_X_AALG_AES256GMAC;
break;
}
ii->ii_authkeylen = ii->ii_enckeylen;
ii->ii_authkey = ii->ii_enckey;
} else if (ii->ii_encalg == SADB_X_EALG_CHACHA20POLY1305) {
ii->ii_authalg = SADB_X_AALG_CHACHA20POLY1305;
ii->ii_authkeylen = ii->ii_enckeylen;
ii->ii_authkey = ii->ii_enckey;
}
tdbp->tdb_encalgxform = txform;
DPRINTF("initialized TDB with enc algorithm %s", txform->name);
tdbp->tdb_ivlen = txform->ivsize;
}
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_X_AALG_RIPEMD160HMAC:
thash = &auth_hash_hmac_ripemd_160_96;
break;
case SADB_X_AALG_SHA2_256:
thash = &auth_hash_hmac_sha2_256_128;
break;
case SADB_X_AALG_SHA2_384:
thash = &auth_hash_hmac_sha2_384_192;
break;
case SADB_X_AALG_SHA2_512:
thash = &auth_hash_hmac_sha2_512_256;
break;
case SADB_X_AALG_AES128GMAC:
thash = &auth_hash_gmac_aes_128;
break;
case SADB_X_AALG_AES192GMAC:
thash = &auth_hash_gmac_aes_192;
break;
case SADB_X_AALG_AES256GMAC:
thash = &auth_hash_gmac_aes_256;
break;
case SADB_X_AALG_CHACHA20POLY1305:
thash = &auth_hash_chacha20_poly1305;
break;
default:
DPRINTF("unsupported authentication algorithm %d "
"specified",
ii->ii_authalg);
return EINVAL;
}
if (ii->ii_authkeylen != thash->keysize) {
DPRINTF("keylength %d doesn't match algorithm %s "
"keysize (%d)",
ii->ii_authkeylen, thash->name, thash->keysize);
return EINVAL;
}
tdbp->tdb_authalgxform = thash;
DPRINTF("initialized TDB with hash algorithm %s", thash->name);
}
tdbp->tdb_xform = xsp;
tdbp->tdb_rpl = AH_HMAC_INITIAL_RPL;
/* Initialize crypto session */
if (tdbp->tdb_encalgxform) {
/* Save the raw keys */
tdbp->tdb_emxkeylen = ii->ii_enckeylen;
tdbp->tdb_emxkey = malloc(tdbp->tdb_emxkeylen, M_XDATA,
M_WAITOK);
memcpy(tdbp->tdb_emxkey, ii->ii_enckey, tdbp->tdb_emxkeylen);
memset(&crie, 0, 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;
tdbp->tdb_amxkey = malloc(tdbp->tdb_amxkeylen, M_XDATA,
M_WAITOK);
memcpy(tdbp->tdb_amxkey, ii->ii_authkey, tdbp->tdb_amxkeylen);
memset(&cria, 0, sizeof(cria));
cria.cri_alg = tdbp->tdb_authalgxform->type;
if ((tdbp->tdb_wnd > 0) && (tdbp->tdb_flags & TDBF_ESN)) {
memset(&crin, 0, sizeof(crin));
crin.cri_alg = CRYPTO_ESN;
cria.cri_next = &crin;
}
cria.cri_klen = ii->ii_authkeylen * 8;
cria.cri_key = ii->ii_authkey;
}
KERNEL_LOCK();
error = crypto_newsession(&tdbp->tdb_cryptoid,
(tdbp->tdb_encalgxform ? &crie : &cria), 0);
KERNEL_UNLOCK();
return error;
}
/*
* Paranoia.
*/
int
esp_zeroize(struct tdb *tdbp)
{
int error;
if (tdbp->tdb_amxkey) {
explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen);
free(tdbp->tdb_amxkey, M_XDATA, tdbp->tdb_amxkeylen);
tdbp->tdb_amxkey = NULL;
}
if (tdbp->tdb_emxkey) {
explicit_bzero(tdbp->tdb_emxkey, tdbp->tdb_emxkeylen);
free(tdbp->tdb_emxkey, M_XDATA, tdbp->tdb_emxkeylen);
tdbp->tdb_emxkey = NULL;
}
KERNEL_LOCK();
error = crypto_freesession(tdbp->tdb_cryptoid);
KERNEL_UNLOCK();
tdbp->tdb_cryptoid = 0;
return error;
}
#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 **mp, struct tdb *tdb, int skip, int protoff)
{
const struct auth_hash *esph = tdb->tdb_authalgxform;
const struct enc_xform *espx = tdb->tdb_encalgxform;
struct mbuf *m = *mp, *m1, *mo;
struct cryptodesc *crde = NULL, *crda = NULL;
struct cryptop *crp = NULL;
int plen, alen, hlen, error, roff;
uint32_t btsx, esn;
#ifdef ENCDEBUG
char buf[INET6_ADDRSTRLEN];
#endif
uint8_t abuf[AH_HMAC_MAX_HASHLEN];
uint8_t lastthree[3], aalg[AH_HMAC_MAX_HASHLEN];
/* Determine the ESP header length */
hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; /* "new" ESP */
alen = esph ? esph->authsize : 0;
plen = m->m_pkthdr.len - (skip + hlen + alen);
if (plen <= 0) {
DPRINTF("invalid payload length");
espstat_inc(esps_badilen);
goto drop;
}
if (espx) {
/*
* Verify payload length is multiple of encryption algorithm
* block size.
*/
if (plen & (espx->blocksize - 1)) {
DPRINTF("payload of %d octets not a multiple "
"of %d octets, SA %s/%08x",
plen, espx->blocksize,
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_badilen);
goto drop;
}
}
/* Replay window checking, if appropriate -- no value commitment. */
if (tdb->tdb_wnd > 0) {
m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
&btsx);
btsx = ntohl(btsx);
switch (checkreplaywindow(tdb, tdb->tdb_rpl, btsx, &esn, 0)) {
case 0: /* All's well */
break;
case 1:
DPRINTF("replay counter wrapped for SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_wrap);
goto drop;
case 2:
DPRINTF("old packet received in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_replay);
goto drop;
case 3:
DPRINTF("duplicate packet received in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_replay);
goto drop;
default:
DPRINTF("bogus value from checkreplaywindow() "
"in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_replay);
goto drop;
}
}
/* Update the counters */
tdb->tdb_cur_bytes += plen;
tdbstat_add(tdb, tdb_ibytes, plen);
espstat_add(esps_ibytes, plen);
/* Hard expiration */
if ((tdb->tdb_flags & TDBF_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes)) {
ipsecstat_inc(ipsec_exctdb);
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD);
tdb_delete(tdb);
goto drop;
}
/* Notify on soft expiration */
mtx_enter(&tdb->tdb_mtx);
if ((tdb->tdb_flags & TDBF_SOFT_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes)) {
tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */
mtx_leave(&tdb->tdb_mtx);
/* may sleep in solock() for the pfkey socket */
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT);
} else
mtx_leave(&tdb->tdb_mtx);
/* Get crypto descriptors */
crp = crypto_getreq(esph && espx ? 2 : 1);
if (crp == NULL) {
DPRINTF("failed to acquire crypto descriptors");
espstat_inc(esps_crypto);
goto drop;
}
if (esph) {
crda = &crp->crp_desc[0];
crde = &crp->crp_desc[1];
/* Authentication descriptor */
crda->crd_skip = skip;
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;
if ((tdb->tdb_wnd > 0) && (tdb->tdb_flags & TDBF_ESN)) {
esn = htonl(esn);
memcpy(crda->crd_esn, &esn, 4);
crda->crd_flags |= CRD_F_ESN;
}
if (espx &&
(espx->type == CRYPTO_AES_GCM_16 ||
espx->type == CRYPTO_CHACHA20_POLY1305))
crda->crd_len = hlen - tdb->tdb_ivlen;
else
crda->crd_len = m->m_pkthdr.len - (skip + alen);
/* Copy the authenticator */
m_copydata(m, m->m_pkthdr.len - alen, alen, abuf);
} else
crde = &crp->crp_desc[0];
/* 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_sid = tdb->tdb_cryptoid;
/* Decryption descriptor */
if (espx) {
crde->crd_skip = skip + hlen;
crde->crd_inject = skip + hlen - tdb->tdb_ivlen;
crde->crd_alg = espx->type;
crde->crd_key = tdb->tdb_emxkey;
crde->crd_klen = tdb->tdb_emxkeylen * 8;
/* XXX Rounds ? */
if (crde->crd_alg == CRYPTO_AES_GMAC)
crde->crd_len = 0;
else
crde->crd_len = plen;
}
while ((error = crypto_invoke(crp)) == EAGAIN) {
/* Reset the session ID */
if (tdb->tdb_cryptoid != 0)
tdb->tdb_cryptoid = crp->crp_sid;
}
if (error) {
DPRINTF("crypto error %d", error);
ipsecstat_inc(ipsec_noxform);
goto drop;
}
/* Release the crypto descriptors */
crypto_freereq(crp);
crp = NULL;
/* If authentication was performed, check now. */
if (esph != NULL) {
/* Copy the authenticator from the packet */
m_copydata(m, m->m_pkthdr.len - esph->authsize,
esph->authsize, aalg);
/* Verify authenticator */
if (timingsafe_bcmp(abuf, aalg, esph->authsize)) {
DPRINTF("authentication failed for packet "
"in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_badauth);
goto drop;
}
/* Remove trailing authenticator */
m_adj(m, -(esph->authsize));
}
/* Replay window checking, if appropriate */
if (tdb->tdb_wnd > 0) {
m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
&btsx);
btsx = ntohl(btsx);
switch (checkreplaywindow(tdb, tdb->tdb_rpl, btsx, &esn, 1)) {
case 0: /* All's well */
#if NPFSYNC > 0
pfsync_update_tdb(tdb,0);
#endif
break;
case 1:
DPRINTF("replay counter wrapped for SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_wrap);
goto drop;
case 2:
DPRINTF("old packet received in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_replay);
goto drop;
case 3:
DPRINTF("duplicate packet received in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_replay);
goto drop;
default:
DPRINTF("bogus value from checkreplaywindow() "
"in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_replay);
goto drop;
}
}
/* Find beginning of ESP header */
m1 = m_getptr(m, skip, &roff);
if (m1 == NULL) {
DPRINTF("bad mbuf chain, SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_hdrops);
goto drop;
}
/* 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 is the first mbuf, it has set M_PKTHDR and m_adj()
* has already adjusted the packet header length for us.
*/
if (m1 != m)
m->m_pkthdr.len -= hlen;
} else if (roff + hlen >= m1->m_len) {
int adjlen;
/*
* 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) {
adjlen = roff + hlen - m1->m_len;
/* Adjust the next mbuf by the remainder */
m_adj(m1->m_next, adjlen);
/* The second mbuf is guaranteed not to have a pkthdr */
m->m_pkthdr.len -= adjlen;
}
/* 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 */
adjlen = m1->m_len - roff;
m_adj(m1, -adjlen);
/*
* If m1 is the first mbuf, it has set M_PKTHDR and m_adj()
* has already adjusted the packet header length for us.
*/
if (m1 != m)
m->m_pkthdr.len -= adjlen;
/* 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.
*/
memmove(mtod(m1, u_char *) + roff,
mtod(m1, u_char *) + roff + hlen,
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) {
DPRINTF("invalid padding length %d for packet in SA %s/%08x",
lastthree[1],
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_badilen);
goto drop;
}
/* Verify correct decryption by checking the last padding bytes */
if ((lastthree[1] != lastthree[0]) && (lastthree[1] != 0)) {
DPRINTF("decryption failed for packet in SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_badenc);
goto drop;
}
/* Trim the mbuf chain to remove the padding */
m_adj(m, -(lastthree[1] + 2));
/* Restore the Next Protocol field */
m_copyback(m, protoff, sizeof(u_int8_t), lastthree + 2, M_NOWAIT);
/* Back to generic IPsec input processing */
return ipsec_common_input_cb(mp, tdb, skip, protoff);
drop:
m_freemp(mp);
crypto_freereq(crp);
return IPPROTO_DONE;
}
/*
* ESP output routine, called by ipsp_process_packet().
*/
int
esp_output(struct mbuf *m, struct tdb *tdb, int skip, int protoff)
{
const struct enc_xform *espx = tdb->tdb_encalgxform;
const struct auth_hash *esph = tdb->tdb_authalgxform;
int ilen, hlen, rlen, padding, blks, alen, roff, error;
uint64_t replay64;
uint32_t replay;
struct mbuf *mi, *mo = (struct mbuf *) NULL;
unsigned char *pad;
uint8_t prot;
#ifdef ENCDEBUG
char buf[INET6_ADDRSTRLEN];
#endif
struct cryptodesc *crde = NULL, *crda = NULL;
struct cryptop *crp = NULL;
#if NBPFILTER > 0
struct ifnet *encif;
if ((encif = enc_getif(tdb->tdb_rdomain, tdb->tdb_tap)) != NULL) {
encif->if_opackets++;
encif->if_obytes += m->m_pkthdr.len;
if (encif->if_bpf) {
struct enchdr hdr;
memset(&hdr, 0, 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;
bpf_mtap_hdr(encif->if_bpf, (char *)&hdr,
ENC_HDRLEN, m, BPF_DIRECTION_OUT);
}
}
#endif
hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen;
rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
if (espx)
blks = MAX(espx->blocksize, 4);
else
blks = 4; /* If no encryption, we have to be 4-byte aligned. */
padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
alen = esph ? esph->authsize : 0;
espstat_inc(esps_output);
switch (tdb->tdb_dst.sa.sa_family) {
case AF_INET:
/* Check for IP maximum packet size violations. */
if (skip + hlen + rlen + padding + alen > IP_MAXPACKET) {
DPRINTF("packet in SA %s/%08x got too big",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_toobig);
error = EMSGSIZE;
goto drop;
}
break;
#ifdef INET6
case AF_INET6:
/* Check for IPv6 maximum packet size violations. */
if (skip + hlen + rlen + padding + alen > IPV6_MAXPACKET) {
DPRINTF("acket in SA %s/%08x got too big",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_toobig);
error = EMSGSIZE;
goto drop;
}
break;
#endif /* INET6 */
default:
DPRINTF("unknown/unsupported protocol family %d, SA %s/%08x",
tdb->tdb_dst.sa.sa_family,
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_nopf);
error = EPFNOSUPPORT;
goto drop;
}
/* Update the counters. */
tdb->tdb_cur_bytes += m->m_pkthdr.len - skip;
espstat_add(esps_obytes, m->m_pkthdr.len - skip);
/* Hard byte expiration. */
if ((tdb->tdb_flags & TDBF_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes)) {
ipsecstat_inc(ipsec_exctdb);
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD);
tdb_delete(tdb);
error = EINVAL;
goto drop;
}
/* Soft byte expiration. */
mtx_enter(&tdb->tdb_mtx);
if ((tdb->tdb_flags & TDBF_SOFT_BYTES) &&
(tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes)) {
tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */
mtx_leave(&tdb->tdb_mtx);
/* may sleep in solock() for the pfkey socket */
pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT);
} else
mtx_leave(&tdb->tdb_mtx);
/*
* Loop through mbuf chain; if we find a readonly mbuf,
* copy the packet.
*/
mi = m;
while (mi != NULL && !M_READONLY(mi))
mi = mi->m_next;
if (mi != NULL) {
struct mbuf *n = m_dup_pkt(m, 0, M_DONTWAIT);
if (n == NULL) {
DPRINTF("bad mbuf chain, SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_hdrops);
error = ENOBUFS;
goto drop;
}
m_freem(m);
m = n;
}
/* Inject ESP header. */
mo = m_makespace(m, skip, hlen, &roff);
if (mo == NULL) {
DPRINTF("failed to inject ESP header for SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_hdrops);
error = ENOBUFS;
goto drop;
}
/* Initialize ESP header. */
memcpy(mtod(mo, caddr_t) + roff, (caddr_t) &tdb->tdb_spi,
sizeof(u_int32_t));
replay64 = tdb->tdb_rpl++; /* used for both header and ESN */
replay = htonl((u_int32_t)replay64);
memcpy(mtod(mo, caddr_t) + roff + sizeof(u_int32_t), (caddr_t) &replay,
sizeof(u_int32_t));
#if NPFSYNC > 0
pfsync_update_tdb(tdb,1);
#endif
/*
* Add padding -- better to do it ourselves than use the crypto engine,
* although if/when we support compression, we'd have to do that.
*/
mo = m_makespace(m, m->m_pkthdr.len, padding + alen, &roff);
if (mo == NULL) {
DPRINTF("m_makespace() failed for SA %s/%08x",
ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)),
ntohl(tdb->tdb_spi));
espstat_inc(esps_hdrops);
error = ENOBUFS;
goto drop;
}
pad = mtod(mo, caddr_t) + roff;
/* Apply self-describing padding */
for (ilen = 0; ilen < padding - 2; ilen++)
pad[ilen] = ilen + 1;
/* 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), &prot, M_NOWAIT);
/* Get crypto descriptors. */
crp = crypto_getreq(esph && espx ? 2 : 1);
if (crp == NULL) {
DPRINTF("failed to acquire crypto descriptors");
espstat_inc(esps_crypto);
error = ENOBUFS;
goto drop;
}
if (espx) {
crde = &crp->crp_desc[0];
crda = &crp->crp_desc[1];
/* Encryption descriptor. */
crde->crd_skip = skip + hlen;
crde->crd_flags = CRD_F_ENCRYPT | CRD_F_IV_EXPLICIT;
crde->crd_inject = skip + hlen - tdb->tdb_ivlen;
/* Encryption operation. */
crde->crd_alg = espx->type;
crde->crd_key = tdb->tdb_emxkey;
crde->crd_klen = tdb->tdb_emxkeylen * 8;
/* XXX Rounds ? */
if (crde->crd_alg == CRYPTO_AES_GMAC)
crde->crd_len = 0;
else
crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
/* GCM & friends just require a NONCE (non-repeating!) */
if (espx->type == CRYPTO_AES_CTR ||
espx->type == CRYPTO_AES_GCM_16 ||
espx->type == CRYPTO_CHACHA20_POLY1305)
bcopy(&replay64, crde->crd_iv, sizeof(replay64));
else
arc4random_buf(crde->crd_iv, espx->ivsize);
} else
crda = &crp->crp_desc[0];
/* 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_sid = tdb->tdb_cryptoid;
if (esph) {
/* Authentication descriptor. */
crda->crd_skip = skip;
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_wnd > 0) && (tdb->tdb_flags & TDBF_ESN)) {
u_int32_t esn;
esn = htonl((u_int32_t)(replay64 >> 32));
memcpy(crda->crd_esn, &esn, 4);
crda->crd_flags |= CRD_F_ESN;
}
if (espx &&
(espx->type == CRYPTO_AES_GCM_16 ||
espx->type == CRYPTO_CHACHA20_POLY1305))
crda->crd_len = hlen - tdb->tdb_ivlen;
else
crda->crd_len = m->m_pkthdr.len - (skip + alen);
}
while ((error = crypto_invoke(crp)) == EAGAIN) {
/* Reset the session ID */
if (tdb->tdb_cryptoid != 0)
tdb->tdb_cryptoid = crp->crp_sid;
}
if (error) {
DPRINTF("crypto error %d", error);
ipsecstat_inc(ipsec_noxform);
goto drop;
}
/* Release the crypto descriptors */
crypto_freereq(crp);
/* Call the IPsec input callback. */
error = ipsp_process_done(m, tdb);
if (error)
espstat_inc(esps_outfail);
return (error);
drop:
m_freem(m);
crypto_freereq(crp);
return error;
}
#define SEEN_SIZE howmany(TDB_REPLAYMAX, 32)
/*
* 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
checkreplaywindow(struct tdb *tdb, u_int64_t t, u_int32_t seq, u_int32_t *seqh,
int commit)
{
u_int32_t tl, th, wl;
u_int32_t packet, window = TDB_REPLAYMAX - TDB_REPLAYWASTE;
int idx, esn = tdb->tdb_flags & TDBF_ESN;
tl = (u_int32_t)t;
th = (u_int32_t)(t >> 32);
/* Zero SN is not allowed */
if ((esn && seq == 0 && tl <= AH_HMAC_INITIAL_RPL && th == 0) ||
(!esn && seq == 0))
return (1);
if (th == 0 && tl < window)
window = tl;
/* Current replay window starts here */
wl = tl - window + 1;
idx = (seq % TDB_REPLAYMAX) / 32;
packet = 1U << (31 - (seq & 31));
/*
* We keep the high part intact when:
* 1) the SN is within [wl, 0xffffffff] and the whole window is
* within one subspace;
* 2) the SN is within [0, wl) and window spans two subspaces.
*/
if ((tl >= window - 1 && seq >= wl) ||
(tl < window - 1 && seq < wl)) {
*seqh = th;
if (seq > tl) {
if (commit) {
if (seq - tl > window)
memset(tdb->tdb_seen, 0,
sizeof(tdb->tdb_seen));
else {
int i = (tl % TDB_REPLAYMAX) / 32;
while (i != idx) {
i = (i + 1) % SEEN_SIZE;
tdb->tdb_seen[i] = 0;
}
}
tdb->tdb_seen[idx] |= packet;
tdb->tdb_rpl = ((u_int64_t)*seqh << 32) | seq;
}
} else {
if (tl - seq >= window)
return (2);
if (tdb->tdb_seen[idx] & packet)
return (3);
if (commit)
tdb->tdb_seen[idx] |= packet;
}
return (0);
}
/* Can't wrap if not doing ESN */
if (!esn)
return (2);
/*
* (3) SN is within [wl, 0xffffffff] and wl is within
* (0xffffffff-window+1, 0xffffffff].
* This means we got a SN which is within our replay window,
* but in the previous subspace.
*/
if (tl < window - 1 && seq >= wl) {
if (tdb->tdb_seen[idx] & packet)
return (3);
*seqh = th - 1;
if (commit)
tdb->tdb_seen[idx] |= packet;
return (0);
}
/*
* (4) SN has wrapped and the last authenticated SN is in the old
* subspace.
*/
*seqh = th + 1;
if (*seqh == 0) /* Don't let high bit to wrap */
return (1);
if (commit) {
if (seq - tl > window)
memset(tdb->tdb_seen, 0, sizeof(tdb->tdb_seen));
else {
int i = (tl % TDB_REPLAYMAX) / 32;
while (i != idx) {
i = (i + 1) % SEEN_SIZE;
tdb->tdb_seen[i] = 0;
}
}
tdb->tdb_seen[idx] |= packet;
tdb->tdb_rpl = ((u_int64_t)*seqh << 32) | seq;
}
return (0);
}
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