* The authors of this code are John Ioannidis (ji@tla.org),

/* $NetBSD: xform_esp.c,v 1.107 2024/07/05 04:31:54 rin Exp $ */
/* $FreeBSD: xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $ */
/* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */

/*
* The authors of this code are John Ioannidis ([email protected]),
* Angelos D. Keromytis ([email protected]) and
* Niels Provos ([email protected]).
*
* 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.107 2024/07/05 04:31:54 rin Exp $");

#if defined(_KERNEL_OPT)
#include "opt_inet.h"
#include "opt_ipsec.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/cprng.h>
#include <sys/pool.h>
#include <sys/pserialize.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_ecn.h>
#include <netinet/ip6.h>

#include <net/route.h>
#include <netipsec/ipsec.h>
#include <netipsec/ipsec_private.h>
#include <netipsec/ah.h>
#include <netipsec/ah_var.h>
#include <netipsec/esp.h>
#include <netipsec/esp_var.h>
#include <netipsec/xform.h>

#ifdef INET6
#include <netinet6/ip6_var.h>
#include <netipsec/ipsec6.h>
#endif

#include <netipsec/key.h>
#include <netipsec/key_debug.h>

#include <opencrypto/cryptodev.h>

percpu_t *espstat_percpu;

int esp_enable = 1;

static int esp_max_ivlen; /* max iv length over all algorithms */

static void esp_input_cb(struct cryptop *op);
static void esp_output_cb(struct cryptop *crp);

const uint8_t esp_stats[256] = { SADB_EALG_STATS_INIT };

static pool_cache_t esp_tdb_crypto_pool_cache;
static size_t esp_pool_item_size;

/*
* NB: this is public for use by the PF_KEY support.
* NB: if you add support here; be sure to add code to esp_attach below!
*/
const struct enc_xform *
esp_algorithm_lookup(int alg)
{

switch (alg) {
case SADB_EALG_DESCBC:
return &enc_xform_des;
case SADB_EALG_3DESCBC:
return &enc_xform_3des;
case SADB_X_EALG_AES:
return &enc_xform_aes;
case SADB_X_EALG_BLOWFISHCBC:
return &enc_xform_blf;
case SADB_X_EALG_CAST128CBC:
return &enc_xform_cast5;
case SADB_X_EALG_SKIPJACK:
return &enc_xform_skipjack;
case SADB_X_EALG_CAMELLIACBC:
return &enc_xform_camellia;
case SADB_X_EALG_AESCTR:
return &enc_xform_aes_ctr;
case SADB_X_EALG_AESGCM16:
return &enc_xform_aes_gcm;
case SADB_X_EALG_AESGMAC:
return &enc_xform_aes_gmac;
case SADB_EALG_NULL:
return &enc_xform_null;
}
return NULL;
}

size_t
esp_hdrsiz(const struct secasvar *sav)
{
size_t size;

if (sav != NULL) {
/*XXX not right for null algorithm--does it matter??*/
KASSERT(sav->tdb_encalgxform != NULL);

/*
* base header size
* + iv length for CBC mode
* + max pad length
* + sizeof(esp trailer)
* + icv length (if any).
*/
if (sav->flags & SADB_X_EXT_OLD)
size = sizeof(struct esp);
else
size = sizeof(struct newesp);
size += sav->tdb_encalgxform->ivsize + 9 +
sizeof(struct esptail);

/*XXX need alg check???*/
if (sav->tdb_authalgxform != NULL && sav->replay)
size += ah_authsiz(sav);
} else {
/*
* base header size
* + max iv length for CBC mode
* + max pad length
* + sizeof(esp trailer)
* + max icv supported.
*/
size = sizeof(struct newesp) + esp_max_ivlen + 9 +
sizeof(struct esptail) + ah_authsiz(NULL);
}
return size;
}

/*
* esp_init() is called when an SPI is being set up.
*/
static int
esp_init(struct secasvar *sav, const struct xformsw *xsp)
{
const struct enc_xform *txform;
struct cryptoini cria, crie, *cr;
int keylen;
int error;

txform = esp_algorithm_lookup(sav->alg_enc);
if (txform == NULL) {
DPRINTF("unsupported encryption algorithm %d\n",
sav->alg_enc);
return EINVAL;
}
if (sav->key_enc == NULL) {
DPRINTF("no encoding key for %s algorithm\n",
txform->name);
return EINVAL;
}
if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
DPRINTF("4-byte IV not supported with protocol\n");
return EINVAL;
}
keylen = _KEYLEN(sav->key_enc);
if (txform->minkey > keylen || keylen > txform->maxkey) {
DPRINTF("invalid key length %u, must be in "
"the range [%u..%u] for algorithm %s\n",
keylen, txform->minkey, txform->maxkey, txform->name);
return EINVAL;
}

sav->ivlen = txform->ivsize;

/*
* Setup AH-related state.
*/
if (sav->alg_auth != 0) {
error = ah_init0(sav, xsp, &cria);
if (error)
return error;
}

/* NB: override anything set in ah_init0 */
sav->tdb_xform = xsp;
sav->tdb_encalgxform = txform;

switch (sav->alg_enc) {
case SADB_X_EALG_AESGCM16:
case SADB_X_EALG_AESGMAC:
switch (keylen) {
case 20:
sav->alg_auth = SADB_X_AALG_AES128GMAC;
sav->tdb_authalgxform = &auth_hash_gmac_aes_128;
break;
case 28:
sav->alg_auth = SADB_X_AALG_AES192GMAC;
sav->tdb_authalgxform = &auth_hash_gmac_aes_192;
break;
case 36:
sav->alg_auth = SADB_X_AALG_AES256GMAC;
sav->tdb_authalgxform = &auth_hash_gmac_aes_256;
break;
default:
DPRINTF("invalid key length %u, must be either of "
"20, 28 or 36\n", keylen);
return EINVAL;
}

memset(&cria, 0, sizeof(cria));
cria.cri_alg = sav->tdb_authalgxform->type;
cria.cri_klen = _KEYBITS(sav->key_enc);
cria.cri_key = _KEYBUF(sav->key_enc);
break;
default:
break;
}

/* Initialize crypto session. */
memset(&crie, 0, sizeof(crie));
crie.cri_alg = sav->tdb_encalgxform->type;
crie.cri_klen = _KEYBITS(sav->key_enc);
crie.cri_key = _KEYBUF(sav->key_enc);
/* XXX Rounds ? */

if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
/* init both auth & enc */
crie.cri_next = &cria;
cr = &crie;
} else if (sav->tdb_encalgxform) {
cr = &crie;
} else if (sav->tdb_authalgxform) {
cr = &cria;
} else {
/* XXX cannot happen? */
DPRINTF("no encoding OR authentication xform!\n");
return EINVAL;
}

return crypto_newsession(&sav->tdb_cryptoid, cr, crypto_support);
}

/*
* Paranoia.
*/
static void
esp_zeroize(struct secasvar *sav)
{
/* NB: ah_zerorize free's the crypto session state */
ah_zeroize(sav);

if (sav->key_enc) {
explicit_memset(_KEYBUF(sav->key_enc), 0,
_KEYLEN(sav->key_enc));
}
sav->tdb_encalgxform = NULL;
sav->tdb_xform = NULL;
}

/*
* ESP input processing, called (eventually) through the protocol switch.
*/
static int
esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
const struct auth_hash *esph;
const struct enc_xform *espx;
struct tdb_crypto *tc;
int plen, alen, hlen, error, stat = ESP_STAT_CRYPTO;
struct newesp *esp;
struct cryptodesc *crde;
struct cryptop *crp;

KASSERT(sav != NULL);
KASSERT(sav->tdb_encalgxform != NULL);
if (__predict_false((skip & 3) != 0 || (m->m_pkthdr.len & 3) != 0)) {
DPRINTF("%s: misaligned packet, skip %u pkt len %u", __func__,
skip, m->m_pkthdr.len);
stat = ESP_STAT_BADILEN; /* Same as FreeBSD */
error = EINVAL;
goto out;
}

/* XXX don't pullup, just copy header */
M_REGION_GET(esp, struct newesp *, m, skip, sizeof(struct newesp));
if (esp == NULL) {
/* m already freed */
return ENOBUFS;
}

esph = sav->tdb_authalgxform;
espx = sav->tdb_encalgxform;
KASSERT(espx != NULL);

/* Determine the ESP header length */
if (sav->flags & SADB_X_EXT_OLD)
hlen = sizeof(struct esp) + sav->ivlen;
else
hlen = sizeof(struct newesp) + sav->ivlen;
/* Authenticator hash size */
alen = esph ? esph->authsize : 0;

/*
* Verify payload length is multiple of encryption algorithm block
* size.
*
* The payload must also be 4-byte-aligned. This is implicitly
* verified here too, since the blocksize is always 4-byte-aligned.
*/
plen = m->m_pkthdr.len - (skip + hlen + alen);
KASSERT((espx->blocksize & 3) == 0);
if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
char buf[IPSEC_ADDRSTRLEN];
DPRINTF("payload of %d octets not a multiple of %d octets,"
" SA %s/%08lx\n", plen, espx->blocksize,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi));
stat = ESP_STAT_BADILEN;
error = EINVAL;
goto out;
}

/*
* Check sequence number.
*/
if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
char logbuf[IPSEC_LOGSASTRLEN];
DPRINTF("packet replay check for %s\n",
ipsec_logsastr(sav, logbuf, sizeof(logbuf)));
stat = ESP_STAT_REPLAY;
error = EACCES;
goto out;
}

/* Update the counters */
ESP_STATADD(ESP_STAT_IBYTES, plen);

/* Get crypto descriptors */
crp = crypto_getreq(esph ? 2 : 1);
if (crp == NULL) {
DPRINTF("failed to acquire crypto descriptors\n");
error = ENOBUFS;
goto out;
}

/* Get IPsec-specific opaque pointer */
size_t extra __diagused = esph == NULL ? 0 : alen;
KASSERTMSG(sizeof(*tc) + extra <= esp_pool_item_size,
"sizeof(*tc) + extra=%zu > esp_pool_item_size=%zu\n",
sizeof(*tc) + extra, esp_pool_item_size);
tc = pool_cache_get(esp_tdb_crypto_pool_cache, PR_NOWAIT);
if (tc == NULL) {
DPRINTF("failed to allocate tdb_crypto\n");
error = ENOBUFS;
goto out1;
}

error = m_makewritable(&m, 0, m->m_pkthdr.len, M_NOWAIT);
if (error) {
DPRINTF("m_makewritable failed\n");
goto out2;
}

if (esph) {
struct cryptodesc *crda;

KASSERT(crp->crp_desc != NULL);
crda = crp->crp_desc;

/* Authentication descriptor */
crda->crd_skip = skip;
if (espx->type == CRYPTO_AES_GCM_16)
crda->crd_len = hlen - sav->ivlen;
else
crda->crd_len = m->m_pkthdr.len - (skip + alen);
crda->crd_inject = m->m_pkthdr.len - alen;

crda->crd_alg = esph->type;
if (espx->type == CRYPTO_AES_GCM_16 ||
espx->type == CRYPTO_AES_GMAC) {
crda->crd_key = _KEYBUF(sav->key_enc);
crda->crd_klen = _KEYBITS(sav->key_enc);
} else {
crda->crd_key = _KEYBUF(sav->key_auth);
crda->crd_klen = _KEYBITS(sav->key_auth);
}

/* Copy the authenticator */
m_copydata(m, m->m_pkthdr.len - alen, alen, (tc + 1));

/* Chain authentication request */
crde = crda->crd_next;
} else {
crde = crp->crp_desc;
}

{
int s = pserialize_read_enter();

/*
* Take another reference to the SA for opencrypto callback.
*/
if (__predict_false(sav->state == SADB_SASTATE_DEAD)) {
pserialize_read_exit(s);
stat = ESP_STAT_NOTDB;
error = ENOENT;
goto out2;
}
KEY_SA_REF(sav);
pserialize_read_exit(s);
}

/* Crypto operation descriptor */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
crp->crp_flags = CRYPTO_F_IMBUF;
crp->crp_buf = m;
crp->crp_callback = esp_input_cb;
crp->crp_sid = sav->tdb_cryptoid;
crp->crp_opaque = tc;

/* These are passed as-is to the callback */
tc->tc_spi = sav->spi;
tc->tc_dst = sav->sah->saidx.dst;
tc->tc_proto = sav->sah->saidx.proto;
tc->tc_protoff = protoff;
tc->tc_skip = skip;
tc->tc_sav = sav;

/* Decryption descriptor */
KASSERTMSG(crde != NULL, "null esp crypto descriptor");
crde->crd_skip = skip + hlen;
if (espx->type == CRYPTO_AES_GMAC)
crde->crd_len = 0;
else
crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
crde->crd_inject = skip + hlen - sav->ivlen;
crde->crd_alg = espx->type;
crde->crd_key = _KEYBUF(sav->key_enc);
crde->crd_klen = _KEYBITS(sav->key_enc);
/* XXX Rounds ? */

crypto_dispatch(crp);
return 0;

out2:
pool_cache_put(esp_tdb_crypto_pool_cache, tc);
out1:
crypto_freereq(crp);
out:
ESP_STATINC(stat);
m_freem(m);
return error;
}

#ifdef INET6
#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) do { \
if (saidx->dst.sa.sa_family == AF_INET6) { \
(void)ipsec6_common_input_cb(m, sav, skip, protoff); \
} else { \
(void)ipsec4_common_input_cb(m, sav, skip, protoff); \
} \
} while (0)
#else
#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) \
((void)ipsec4_common_input_cb(m, sav, skip, protoff))
#endif

/*
* ESP input callback from the crypto driver.
*/
static void
esp_input_cb(struct cryptop *crp)
{
char buf[IPSEC_ADDRSTRLEN];
uint8_t lastthree[3], aalg[AH_ALEN_MAX];
int hlen, skip, protoff;
struct mbuf *m;
const struct auth_hash *esph;
struct tdb_crypto *tc;
struct secasvar *sav;
struct secasindex *saidx;
void *ptr;
IPSEC_DECLARE_LOCK_VARIABLE;

KASSERT(crp->crp_desc != NULL);
KASSERT(crp->crp_opaque != NULL);

tc = crp->crp_opaque;
skip = tc->tc_skip;
protoff = tc->tc_protoff;
m = crp->crp_buf;

IPSEC_ACQUIRE_GLOBAL_LOCKS();

sav = tc->tc_sav;
saidx = &sav->sah->saidx;
KASSERTMSG(saidx->dst.sa.sa_family == AF_INET ||
saidx->dst.sa.sa_family == AF_INET6,
"unexpected protocol family %u", saidx->dst.sa.sa_family);

esph = sav->tdb_authalgxform;

/* Check for crypto errors */
if (crp->crp_etype) {
/* Reset the session ID */
if (sav->tdb_cryptoid != 0)
sav->tdb_cryptoid = crp->crp_sid;

ESP_STATINC(ESP_STAT_NOXFORM);
DPRINTF("crypto error %d\n", crp->crp_etype);
goto bad;
}

ESP_STATINC(ESP_STAT_HIST + esp_stats[sav->alg_enc]);

/* 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. Otherwise we need to
* check the authentication calculation.
*/
AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]);
/* Copy the authenticator from the packet */
m_copydata(m, m->m_pkthdr.len - esph->authsize,
esph->authsize, aalg);

ptr = (tc + 1);

/* Verify authenticator */
if (!consttime_memequal(ptr, aalg, esph->authsize)) {
DPRINTF("authentication hash mismatch "
"for packet in SA %s/%08lx\n",
ipsec_address(&saidx->dst, buf,
sizeof(buf)), (u_long) ntohl(sav->spi));
ESP_STATINC(ESP_STAT_BADAUTH);
goto bad;
}

/* Remove trailing authenticator */
m_adj(m, -(esph->authsize));
}

/* Release the crypto descriptors */
pool_cache_put(esp_tdb_crypto_pool_cache, tc);
tc = NULL;
crypto_freereq(crp);
crp = NULL;

/*
* Packet is now decrypted.
*/
m->m_flags |= M_DECRYPTED;

/*
* Update replay sequence number, if appropriate.
*/
if (sav->replay) {
uint32_t seq;

m_copydata(m, skip + offsetof(struct newesp, esp_seq),
sizeof(seq), &seq);
if (ipsec_updatereplay(ntohl(seq), sav)) {
char logbuf[IPSEC_LOGSASTRLEN];
DPRINTF("packet replay check for %s\n",
ipsec_logsastr(sav, logbuf, sizeof(logbuf)));
ESP_STATINC(ESP_STAT_REPLAY);
goto bad;
}
}

/* Determine the ESP header length */
if (sav->flags & SADB_X_EXT_OLD)
hlen = sizeof(struct esp) + sav->ivlen;
else
hlen = sizeof(struct newesp) + sav->ivlen;

/* Remove the ESP header and IV from the mbuf. */
if (m_striphdr(m, skip, hlen) != 0) {
ESP_STATINC(ESP_STAT_HDROPS);
DPRINTF("bad mbuf chain, SA %s/%08lx\n",
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi));
goto bad;
}

/* 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) {
ESP_STATINC(ESP_STAT_BADILEN);
DPRINTF("invalid padding length %d "
"for %u byte packet in SA %s/%08lx\n",
lastthree[1], m->m_pkthdr.len - skip,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi));
goto bad;
}

/* Verify correct decryption by checking the last padding bytes */
if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
ESP_STATINC(ESP_STAT_BADENC);
DPRINTF("decryption failed for packet in SA "
"%s/%08lx\n",
ipsec_address(&sav->sah->saidx.dst, buf,
sizeof(buf)), (u_long) ntohl(sav->spi));
DPRINTF("%x %x\n", lastthree[0],
lastthree[1]);
goto bad;
}
}

/* Trim the mbuf chain to remove trailing authenticator and padding */
m_adj(m, -(lastthree[1] + 2));

/* Restore the Next Protocol field */
m_copyback(m, protoff, sizeof(uint8_t), lastthree + 2);

IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff);

KEY_SA_UNREF(&sav);
IPSEC_RELEASE_GLOBAL_LOCKS();
return;
bad:
if (sav)
KEY_SA_UNREF(&sav);
IPSEC_RELEASE_GLOBAL_LOCKS();
m_freem(m);
if (tc != NULL)
pool_cache_put(esp_tdb_crypto_pool_cache, tc);
if (crp != NULL)
crypto_freereq(crp);
}

/*
* ESP output routine, called by ipsec[46]_process_packet().
*/
static int
esp_output(struct mbuf *m, const struct ipsecrequest *isr, struct secasvar *sav,
int skip, int protoff, int flags)
{
char buf[IPSEC_ADDRSTRLEN];
const struct enc_xform *espx;
const struct auth_hash *esph;
int hlen, rlen, tlen, padlen, blks, alen, i, roff;
struct mbuf *mo = NULL;
struct tdb_crypto *tc;
struct secasindex *saidx;
unsigned char *tail;
uint8_t prot;
int error, maxpacketsize;
struct esptail *esptail;
struct cryptodesc *crde, *crda;
struct cryptop *crp;

esph = sav->tdb_authalgxform;
espx = sav->tdb_encalgxform;
KASSERT(espx != NULL);

/* Determine the ESP header length */
if (sav->flags & SADB_X_EXT_OLD)
hlen = sizeof(struct esp) + sav->ivlen;
else
hlen = sizeof(struct newesp) + sav->ivlen;
/* Authenticator hash size */
alen = esph ? esph->authsize : 0;

/*
* NB: The null encoding transform has a blocksize of 4
* so that headers are properly aligned.
*/
blks = espx->blocksize; /* IV blocksize */

/* Raw payload length. */
rlen = m->m_pkthdr.len - skip;

/* Encryption padding. */
padlen = ((blks - ((rlen + sizeof(struct esptail)) % blks)) % blks);

/* Length of what we append (tail). */
tlen = padlen + sizeof(struct esptail) + alen;

ESP_STATINC(ESP_STAT_OUTPUT);

saidx = &sav->sah->saidx;
/* Check for maximum packet size violations. */
switch (saidx->dst.sa.sa_family) {
#ifdef INET
case AF_INET:
maxpacketsize = IP_MAXPACKET;
break;
#endif
#ifdef INET6
case AF_INET6:
maxpacketsize = IPV6_MAXPACKET;
break;
#endif
default:
DPRINTF("unknown/unsupported protocol family %d, "
"SA %s/%08lx\n", saidx->dst.sa.sa_family,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long)ntohl(sav->spi));
ESP_STATINC(ESP_STAT_NOPF);
error = EPFNOSUPPORT;
goto bad;
}
if (skip + hlen + rlen + tlen > maxpacketsize) {
DPRINTF("packet in SA %s/%08lx got too big (len %u, "
"max len %u)\n",
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi),
skip + hlen + rlen + tlen, maxpacketsize);
ESP_STATINC(ESP_STAT_TOOBIG);
error = EMSGSIZE;
goto bad;
}

/* Update the counters. */
ESP_STATADD(ESP_STAT_OBYTES, m->m_pkthdr.len - skip);

m = m_clone(m);
if (m == NULL) {
DPRINTF("cannot clone mbuf chain, SA %s/%08lx\n",
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi));
ESP_STATINC(ESP_STAT_HDROPS);
error = ENOBUFS;
goto bad;
}

/* Inject ESP header. */
mo = m_makespace(m, skip, hlen, &roff);
if (mo == NULL) {
DPRINTF("failed to inject %u byte ESP hdr for SA "
"%s/%08lx\n", hlen,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi));
ESP_STATINC(ESP_STAT_HDROPS);
error = ENOBUFS;
goto bad;
}

/* Initialize ESP header. */
memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(uint32_t));
if (sav->replay) {
uint32_t replay;

#ifdef IPSEC_DEBUG
/* Emulate replay attack when ipsec_replay is TRUE. */
if (ipsec_replay)
replay = htonl(sav->replay->count);
else
#endif
replay = htonl(atomic_inc_32_nv(&sav->replay->count));

memcpy(mtod(mo,char *) + roff + sizeof(uint32_t), &replay,
sizeof(uint32_t));
}

/*
* Grow the mbuf, we will append data at the tail.
*/
tail = m_pad(m, tlen);
if (tail == NULL) {
DPRINTF("m_pad failed for SA %s/%08lx\n",
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi));
m = NULL;
error = ENOBUFS;
goto bad;
}

/*
* Add padding: random, zero, or self-describing.
*/
switch (sav->flags & SADB_X_EXT_PMASK) {
case SADB_X_EXT_PSEQ:
for (i = 0; i < padlen; i++)
tail[i] = i + 1;
break;
case SADB_X_EXT_PRAND:
(void)cprng_fast(tail, padlen);
break;
case SADB_X_EXT_PZERO:
default:
memset(tail, 0, padlen);
break;
}

/* Build the ESP Trailer. */
esptail = (struct esptail *)&tail[padlen];
esptail->esp_padlen = padlen;
m_copydata(m, protoff, sizeof(uint8_t), &esptail->esp_nxt);

/* Fix Next Protocol in IPv4/IPv6 header. */
prot = IPPROTO_ESP;
m_copyback(m, protoff, sizeof(uint8_t), &prot);

/* Get crypto descriptors. */
crp = crypto_getreq(esph ? 2 : 1);
if (crp == NULL) {
DPRINTF("failed to acquire crypto descriptors\n");
ESP_STATINC(ESP_STAT_CRYPTO);
error = ENOBUFS;
goto bad;
}

/* Get the descriptors. */
crde = crp->crp_desc;
crda = crde->crd_next;

/* Encryption descriptor. */
crde->crd_skip = skip + hlen;
if (espx->type == CRYPTO_AES_GMAC)
crde->crd_len = 0;
else
crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
crde->crd_flags = CRD_F_ENCRYPT;
crde->crd_inject = skip + hlen - sav->ivlen;
crde->crd_alg = espx->type;
crde->crd_key = _KEYBUF(sav->key_enc);
crde->crd_klen = _KEYBITS(sav->key_enc);
/* XXX Rounds ? */

/* IPsec-specific opaque crypto info. */
tc = pool_cache_get(esp_tdb_crypto_pool_cache, PR_NOWAIT);
if (tc == NULL) {
crypto_freereq(crp);
DPRINTF("failed to allocate tdb_crypto\n");
ESP_STATINC(ESP_STAT_CRYPTO);
error = ENOBUFS;
goto bad;
}

{
int s = pserialize_read_enter();

/*
* Take another reference to the SP and the SA for opencrypto callback.
*/
if (__predict_false(isr->sp->state == IPSEC_SPSTATE_DEAD ||
sav->state == SADB_SASTATE_DEAD)) {
pserialize_read_exit(s);
pool_cache_put(esp_tdb_crypto_pool_cache, tc);
crypto_freereq(crp);
ESP_STATINC(ESP_STAT_NOTDB);
error = ENOENT;
goto bad;
}
KEY_SP_REF(isr->sp);
KEY_SA_REF(sav);
pserialize_read_exit(s);
}

/* Callback parameters */
tc->tc_isr = isr;
tc->tc_spi = sav->spi;
tc->tc_dst = saidx->dst;
tc->tc_proto = saidx->proto;
tc->tc_flags = flags;
tc->tc_sav = sav;

/* Crypto operation descriptor. */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
crp->crp_flags = CRYPTO_F_IMBUF;
crp->crp_buf = m;
crp->crp_callback = esp_output_cb;
crp->crp_opaque = tc;
crp->crp_sid = sav->tdb_cryptoid;

if (esph) {
/* Authentication descriptor. */
crda->crd_skip = skip;
if (espx->type == CRYPTO_AES_GCM_16)
crda->crd_len = hlen - sav->ivlen;
else
crda->crd_len = m->m_pkthdr.len - (skip + alen);
crda->crd_inject = m->m_pkthdr.len - alen;

/* Authentication operation. */
crda->crd_alg = esph->type;
if (espx->type == CRYPTO_AES_GCM_16 ||
espx->type == CRYPTO_AES_GMAC) {
crda->crd_key = _KEYBUF(sav->key_enc);
crda->crd_klen = _KEYBITS(sav->key_enc);
} else {
crda->crd_key = _KEYBUF(sav->key_auth);
crda->crd_klen = _KEYBITS(sav->key_auth);
}
}

crypto_dispatch(crp);
return 0;

bad:
m_freem(m);
return error;
}

/*
* ESP output callback from the crypto driver.
*/
static void
esp_output_cb(struct cryptop *crp)
{
struct tdb_crypto *tc;
const struct ipsecrequest *isr;
struct secasvar *sav;
struct mbuf *m;
int flags;
IPSEC_DECLARE_LOCK_VARIABLE;

KASSERT(crp->crp_opaque != NULL);
tc = crp->crp_opaque;
m = crp->crp_buf;

IPSEC_ACQUIRE_GLOBAL_LOCKS();

isr = tc->tc_isr;
sav = tc->tc_sav;

/* Check for crypto errors. */
if (crp->crp_etype) {
/* Reset session ID. */
if (sav->tdb_cryptoid != 0)
sav->tdb_cryptoid = crp->crp_sid;

ESP_STATINC(ESP_STAT_NOXFORM);
DPRINTF("crypto error %d\n", crp->crp_etype);
goto bad;
}

ESP_STATINC(ESP_STAT_HIST + esp_stats[sav->alg_enc]);
if (sav->tdb_authalgxform != NULL)
AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]);

flags = tc->tc_flags;
/* Release crypto descriptors. */
pool_cache_put(esp_tdb_crypto_pool_cache, tc);
crypto_freereq(crp);

#ifdef IPSEC_DEBUG
/* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
if (ipsec_integrity) {
static unsigned char ipseczeroes[AH_ALEN_MAX];
const struct auth_hash *esph;

/*
* Corrupt HMAC if we want to test integrity verification of
* the other side.
*/
esph = sav->tdb_authalgxform;
if (esph != NULL) {
m_copyback(m, m->m_pkthdr.len - esph->authsize,
esph->authsize, ipseczeroes);
}
}
#endif

/* NB: m is reclaimed by ipsec_process_done. */
(void)ipsec_process_done(m, isr, sav, flags);
KEY_SA_UNREF(&sav);
KEY_SP_UNREF(&isr->sp);
IPSEC_RELEASE_GLOBAL_LOCKS();
return;

bad:
if (sav)
KEY_SA_UNREF(&sav);
KEY_SP_UNREF(&isr->sp);
IPSEC_RELEASE_GLOBAL_LOCKS();
m_freem(m);
pool_cache_put(esp_tdb_crypto_pool_cache, tc);
crypto_freereq(crp);
}

static struct xformsw esp_xformsw = {
.xf_type = XF_ESP,
.xf_flags = XFT_CONF|XFT_AUTH,
.xf_name = "IPsec ESP",
.xf_init = esp_init,
.xf_zeroize = esp_zeroize,
.xf_input = esp_input,
.xf_output = esp_output,
.xf_next = NULL,
};

void
esp_attach(void)
{

espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS);

extern int ah_max_authsize;
KASSERT(ah_max_authsize != 0);
esp_pool_item_size = sizeof(struct tdb_crypto) + ah_max_authsize;
esp_tdb_crypto_pool_cache = pool_cache_init(esp_pool_item_size,
coherency_unit, 0, 0, "esp_tdb_crypto", NULL, IPL_SOFTNET,
NULL, NULL, NULL);

#define MAXIV(xform) \
if (xform.ivsize > esp_max_ivlen) \
esp_max_ivlen = xform.ivsize \

esp_max_ivlen = 0;
MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */
MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */
MAXIV(enc_xform_aes); /* SADB_X_EALG_AES */
MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */
MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */
MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */
MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */
MAXIV(enc_xform_aes_ctr); /* SADB_X_EALG_AESCTR */
MAXIV(enc_xform_null); /* SADB_EALG_NULL */

xform_register(&esp_xformsw);
#undef MAXIV
}