freebsd-dev/sys/crypto/via/padlock.c

/*-
 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * Copyright (c) 2004 Mark R V Murray
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*	$OpenBSD: via.c,v 1.3 2004/06/15 23:36:55 deraadt Exp $	*/
/*-
 * Copyright (c) 2003 Jason Wright
 * Copyright (c) 2003, 2004 Theo de Raadt
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/libkern.h>
#if defined(__i386__) && !defined(PC98)
#include <machine/cpufunc.h>
#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#endif

#include <opencrypto/cryptodev.h>
#include <opencrypto/cryptosoft.h> /* for hmac_ipad_buffer and hmac_opad_buffer */
#include <opencrypto/xform.h>
#include <crypto/rijndael/rijndael.h>


#define	PADLOCK_ROUND_COUNT_AES128	10
#define	PADLOCK_ROUND_COUNT_AES192	12
#define	PADLOCK_ROUND_COUNT_AES256	14

#define	PADLOCK_ALGORITHM_TYPE_AES	0

#define	PADLOCK_KEY_GENERATION_HW	0
#define	PADLOCK_KEY_GENERATION_SW	1

#define	PADLOCK_DIRECTION_ENCRYPT	0
#define	PADLOCK_DIRECTION_DECRYPT	1

#define	PADLOCK_KEY_SIZE_128	0
#define	PADLOCK_KEY_SIZE_192	1
#define	PADLOCK_KEY_SIZE_256	2

union padlock_cw {
	uint64_t raw;
	struct {
		u_int round_count : 4;
		u_int algorithm_type : 3;
		u_int key_generation : 1;
		u_int intermediate : 1;
		u_int direction : 1;
		u_int key_size : 2;
		u_int filler0 : 20;
		u_int filler1 : 32;
		u_int filler2 : 32;
		u_int filler3 : 32;
	} __field;
};
#define	cw_round_count		__field.round_count
#define	cw_algorithm_type	__field.algorithm_type
#define	cw_key_generation	__field.key_generation
#define	cw_intermediate		__field.intermediate
#define	cw_direction		__field.direction
#define	cw_key_size		__field.key_size
#define	cw_filler0		__field.filler0
#define	cw_filler1		__field.filler1
#define	cw_filler2		__field.filler2
#define	cw_filler3		__field.filler3

struct padlock_session {
	union padlock_cw ses_cw __aligned(16);
	uint32_t	ses_ekey[4 * (RIJNDAEL_MAXNR + 1) + 4] __aligned(16);	/* 128 bit aligned */
	uint32_t	ses_dkey[4 * (RIJNDAEL_MAXNR + 1) + 4] __aligned(16);	/* 128 bit aligned */
	uint8_t		ses_iv[16] __aligned(16);			/* 128 bit aligned */
	struct auth_hash *ses_axf;
	uint8_t		*ses_ictx;
	uint8_t		*ses_octx;
	int		ses_mlen;
	int		ses_used;
	uint32_t	ses_id;
	TAILQ_ENTRY(padlock_session) ses_next;
};

struct padlock_softc {
	int32_t		sc_cid;
	uint32_t	sc_sid;
	TAILQ_HEAD(, padlock_session) sc_sessions;
	struct mtx	sc_sessions_mtx;
};

static struct padlock_softc *padlock_sc;

static int padlock_newsession(void *arg __unused, uint32_t *sidp,
    struct cryptoini *cri);
static int padlock_freesession(void *arg __unused, uint64_t tid);
static int padlock_process(void *arg __unused, struct cryptop *crp,
    int hint __unused);

static __inline void
padlock_cbc(void *in, void *out, size_t count, void *key, union padlock_cw *cw,
    void *iv)
{
#ifdef __GNUCLIKE_ASM
	/* The .byte line is really VIA C3 "xcrypt-cbc" instruction */
	__asm __volatile(
		"pushf				\n\t"
		"popf				\n\t"
		"rep				\n\t"
		".byte	0x0f, 0xa7, 0xd0"
			: "+a" (iv), "+c" (count), "+D" (out), "+S" (in)
			: "b" (key), "d" (cw)
			: "cc", "memory"
		);
#endif
}

static int
padlock_init(void)
{
	struct padlock_softc *sc;
#if defined(__i386__) && !defined(PC98)
	if (!(via_feature_xcrypt & VIA_HAS_AES)) {
		printf("PADLOCK: No ACE support.\n");
		return (EINVAL);
	} else
		printf("PADLOCK: HW support loaded.\n");
#else
	return (EINVAL);
#endif

	padlock_sc = sc = malloc(sizeof(*padlock_sc), M_DEVBUF,
	    M_WAITOK | M_ZERO);
	TAILQ_INIT(&sc->sc_sessions);
	sc->sc_sid = 1;

	sc->sc_cid = crypto_get_driverid(0);
	if (sc->sc_cid < 0) {
		printf("PADLOCK: Could not get crypto driver id.\n");
		free(padlock_sc, M_DEVBUF);
		padlock_sc = NULL;
		return (ENOMEM);
	}       

	mtx_init(&sc->sc_sessions_mtx, "padlock_mtx", NULL, MTX_DEF);
	crypto_register(sc->sc_cid, CRYPTO_AES_CBC, 0, 0, padlock_newsession,
	    padlock_freesession, padlock_process, NULL);
	crypto_register(sc->sc_cid, CRYPTO_MD5_HMAC, 0, 0, padlock_newsession,
	    padlock_freesession, padlock_process, NULL);
	crypto_register(sc->sc_cid, CRYPTO_SHA1_HMAC, 0, 0, padlock_newsession,
	    padlock_freesession, padlock_process, NULL);
	crypto_register(sc->sc_cid, CRYPTO_RIPEMD160_HMAC, 0, 0,
	    padlock_newsession, padlock_freesession, padlock_process, NULL);
	crypto_register(sc->sc_cid, CRYPTO_SHA2_256_HMAC, 0, 0,
	    padlock_newsession, padlock_freesession, padlock_process, NULL);
	crypto_register(sc->sc_cid, CRYPTO_SHA2_384_HMAC, 0, 0,
	    padlock_newsession, padlock_freesession, padlock_process, NULL);
	crypto_register(sc->sc_cid, CRYPTO_SHA2_512_HMAC, 0, 0,
	    padlock_newsession, padlock_freesession, padlock_process, NULL);
	return (0);
}

static int
padlock_destroy(void)
{
	struct padlock_softc *sc = padlock_sc;
	struct padlock_session *ses;
	u_int active = 0;

	if (sc == NULL)
		return (0);
	mtx_lock(&sc->sc_sessions_mtx);
	TAILQ_FOREACH(ses, &sc->sc_sessions, ses_next) {
		if (ses->ses_used)
			active++;
	}
	if (active > 0) {
		mtx_unlock(&sc->sc_sessions_mtx);
		printf("PADLOCK: Cannot destroy, %u sessions active.\n",
		    active);
		return (EBUSY);
	}
	padlock_sc = NULL;
	for (ses = TAILQ_FIRST(&sc->sc_sessions); ses != NULL;
	    ses = TAILQ_FIRST(&sc->sc_sessions)) {
		TAILQ_REMOVE(&sc->sc_sessions, ses, ses_next);
		free(ses, M_DEVBUF);
	}
	mtx_destroy(&sc->sc_sessions_mtx);
	crypto_unregister_all(sc->sc_cid);
	free(sc, M_DEVBUF);
	return (0);
}

static void
padlock_setup_enckey(struct padlock_session *ses, caddr_t key, int klen)
{
	union padlock_cw *cw;
	int i;

	cw = &ses->ses_cw;
	if (cw->cw_key_generation == PADLOCK_KEY_GENERATION_SW) {
		/* Build expanded keys for both directions */
		rijndaelKeySetupEnc(ses->ses_ekey, key, klen);
		rijndaelKeySetupDec(ses->ses_dkey, key, klen);
		for (i = 0; i < 4 * (RIJNDAEL_MAXNR + 1); i++) {
			ses->ses_ekey[i] = ntohl(ses->ses_ekey[i]);
			ses->ses_dkey[i] = ntohl(ses->ses_dkey[i]);
		}
	} else {
		bcopy(key, ses->ses_ekey, klen);
		bcopy(key, ses->ses_dkey, klen);
	}
}

static void
padlock_setup_mackey(struct padlock_session *ses, caddr_t key, int klen)
{
	struct auth_hash *axf;
	int i;

	klen /= 8;
	axf = ses->ses_axf;

	for (i = 0; i < klen; i++)
		key[i] ^= HMAC_IPAD_VAL;

	axf->Init(ses->ses_ictx);
	axf->Update(ses->ses_ictx, key, klen);
	axf->Update(ses->ses_ictx, hmac_ipad_buffer, axf->blocksize - klen);

	for (i = 0; i < klen; i++)
		key[i] ^= (HMAC_IPAD_VAL ^ HMAC_OPAD_VAL);

	axf->Init(ses->ses_octx); 
	axf->Update(ses->ses_octx, key, klen);
	axf->Update(ses->ses_octx, hmac_opad_buffer, axf->blocksize - klen);

	for (i = 0; i < klen; i++)
		key[i] ^= HMAC_OPAD_VAL;
}

/*
 * Compute keyed-hash authenticator.
 */
static int
padlock_authcompute(struct padlock_session *ses, struct cryptodesc *crd,
    caddr_t buf, int flags)
{
	u_char hash[HASH_MAX_LEN];
	struct auth_hash *axf;
	union authctx ctx;
	int error;

	axf = ses->ses_axf;

	bcopy(ses->ses_ictx, &ctx, axf->ctxsize);

	error = crypto_apply(flags, buf, crd->crd_skip, crd->crd_len,
	    (int (*)(void *, void *, unsigned int))axf->Update, (caddr_t)&ctx);
	if (error != 0)
		return (error);

	axf->Final(hash, &ctx);
	bcopy(ses->ses_octx, &ctx, axf->ctxsize);
	axf->Update(&ctx, hash, axf->hashsize);
	axf->Final(hash, &ctx);

	/* Inject the authentication data */
	crypto_copyback(flags, buf, crd->crd_inject,
	    ses->ses_mlen == 0 ? axf->hashsize : ses->ses_mlen, hash);
	return (0);
}


static int
padlock_newsession(void *arg __unused, uint32_t *sidp, struct cryptoini *cri)
{
	struct padlock_softc *sc = padlock_sc;
	struct padlock_session *ses = NULL;
	struct cryptoini *encini, *macini;
	union padlock_cw *cw;

	if (sc == NULL || sidp == NULL || cri == NULL)
		return (EINVAL);

	encini = macini = NULL;
	for (; cri != NULL; cri = cri->cri_next) {
		switch (cri->cri_alg) {
		case CRYPTO_NULL_HMAC:
		case CRYPTO_MD5_HMAC:
		case CRYPTO_SHA1_HMAC:
		case CRYPTO_RIPEMD160_HMAC:
		case CRYPTO_SHA2_256_HMAC:
		case CRYPTO_SHA2_384_HMAC:
		case CRYPTO_SHA2_512_HMAC:
			if (macini != NULL)
				return (EINVAL);
			macini = cri;
			break;
		case CRYPTO_AES_CBC:
			if (encini != NULL)
				return (EINVAL);
			encini = cri;
			break;
		default:
			return (EINVAL);
		}
	}

	/*
	 * We only support HMAC algorithms to be able to work with
	 * fast_ipsec(4), so if we are asked only for authentication without
	 * encryption, don't pretend we can accellerate it.
	 */
	if (encini == NULL)
		return (EINVAL);
	if (encini->cri_klen != 128 && encini->cri_klen != 192 &&
	    encini->cri_klen != 256) {
		return (EINVAL);
	}

	/*
	 * Let's look for a free session structure.
	 */
	mtx_lock(&sc->sc_sessions_mtx);
	/*
	 * Free sessions goes first, so if first session is used, we need to
	 * allocate one.
	 */
	ses = TAILQ_FIRST(&sc->sc_sessions);
	if (ses == NULL || ses->ses_used)
		ses = NULL;
	else {
		TAILQ_REMOVE(&sc->sc_sessions, ses, ses_next);
		ses->ses_used = 1;
		TAILQ_INSERT_TAIL(&sc->sc_sessions, ses, ses_next);
	}
	mtx_unlock(&sc->sc_sessions_mtx);
	if (ses == NULL) {
		ses = malloc(sizeof(*ses), M_DEVBUF, M_NOWAIT | M_ZERO);
		if (ses == NULL)
			return (ENOMEM);
		ses->ses_used = 1;
		mtx_lock(&sc->sc_sessions_mtx);
		ses->ses_id = sc->sc_sid++;
		TAILQ_INSERT_TAIL(&sc->sc_sessions, ses, ses_next);
		mtx_unlock(&sc->sc_sessions_mtx);
	}

	cw = &ses->ses_cw;
	bzero(cw, sizeof(*cw));
	cw->cw_algorithm_type = PADLOCK_ALGORITHM_TYPE_AES;
	cw->cw_key_generation = PADLOCK_KEY_GENERATION_SW;
	cw->cw_intermediate = 0;
	switch (encini->cri_klen) {
	case 128:
		cw->cw_round_count = PADLOCK_ROUND_COUNT_AES128;
		cw->cw_key_size = PADLOCK_KEY_SIZE_128;
#ifdef HW_KEY_GENERATION
		/* This doesn't buy us much, that's why it is commented out. */
		cw->cw_key_generation = PADLOCK_KEY_GENERATION_HW;
#endif
		break;
	case 192:
		cw->cw_round_count = PADLOCK_ROUND_COUNT_AES192;
		cw->cw_key_size = PADLOCK_KEY_SIZE_192;
		break;
	case 256:
		cw->cw_round_count = PADLOCK_ROUND_COUNT_AES256;
		cw->cw_key_size = PADLOCK_KEY_SIZE_256;
		break;
	}
	if (encini->cri_key != NULL)
		padlock_setup_enckey(ses, encini->cri_key, encini->cri_klen);

	arc4rand(ses->ses_iv, sizeof(ses->ses_iv), 0);

	if (macini != NULL) {
		ses->ses_mlen = macini->cri_mlen;

		/* Find software structure which describes HMAC algorithm. */
		switch (macini->cri_alg) {
		case CRYPTO_NULL_HMAC:
			ses->ses_axf = &auth_hash_null;
			break;
		case CRYPTO_MD5_HMAC:
			ses->ses_axf = &auth_hash_hmac_md5;
			break;
		case CRYPTO_SHA1_HMAC:
			ses->ses_axf = &auth_hash_hmac_sha1;
			break;
		case CRYPTO_RIPEMD160_HMAC:
			ses->ses_axf = &auth_hash_hmac_ripemd_160;
			break;
		case CRYPTO_SHA2_256_HMAC:
			ses->ses_axf = &auth_hash_hmac_sha2_256;
			break;
		case CRYPTO_SHA2_384_HMAC:
			ses->ses_axf = &auth_hash_hmac_sha2_384;
			break;
		case CRYPTO_SHA2_512_HMAC:
			ses->ses_axf = &auth_hash_hmac_sha2_512;
			break;
		}

		/* Allocate memory for HMAC inner and outer contexts. */
		ses->ses_ictx = malloc(ses->ses_axf->ctxsize, M_CRYPTO_DATA,
		    M_NOWAIT);
		ses->ses_octx = malloc(ses->ses_axf->ctxsize, M_CRYPTO_DATA,
		    M_NOWAIT);
		if (ses->ses_ictx == NULL || ses->ses_octx == NULL) {
			padlock_freesession(NULL, ses->ses_id);
			return (ENOMEM);
		}

		/* Setup key if given. */
		if (macini->cri_key != NULL) {
			padlock_setup_mackey(ses, macini->cri_key,
			    macini->cri_klen);
		}
	}

	*sidp = ses->ses_id;
	return (0);
}

static int
padlock_freesession(void *arg __unused, uint64_t tid)
{
	struct padlock_softc *sc = padlock_sc;
	struct padlock_session *ses;
	uint32_t sid = ((uint32_t)tid) & 0xffffffff;

	if (sc == NULL)
		return (EINVAL);
	mtx_lock(&sc->sc_sessions_mtx);
	TAILQ_FOREACH(ses, &sc->sc_sessions, ses_next) {
		if (ses->ses_id == sid)
			break;
	}
	if (ses == NULL) {
		mtx_unlock(&sc->sc_sessions_mtx);
		return (EINVAL);
	}
	TAILQ_REMOVE(&sc->sc_sessions, ses, ses_next);
	if (ses->ses_ictx != NULL) {
		bzero(ses->ses_ictx, ses->ses_axf->ctxsize);
		free(ses->ses_ictx, M_CRYPTO_DATA);
		ses->ses_ictx = NULL;
	}
	if (ses->ses_octx != NULL) {
		bzero(ses->ses_ictx, ses->ses_axf->ctxsize);
		free(ses->ses_octx, M_CRYPTO_DATA);
		ses->ses_octx = NULL;
	}
	bzero(ses, sizeof(*ses));
	ses->ses_used = 0;
	TAILQ_INSERT_TAIL(&sc->sc_sessions, ses, ses_next);
	mtx_unlock(&sc->sc_sessions_mtx);
	return (0);
}

static int
padlock_process(void *arg __unused, struct cryptop *crp, int hint __unused)
{
	struct padlock_softc *sc = padlock_sc;
	struct padlock_session *ses;
	union padlock_cw *cw;
	struct cryptodesc *crd, *enccrd, *maccrd;
	uint32_t *key;
	u_char *buf, *abuf;
	int error = 0;

	enccrd = maccrd = NULL;
	buf = NULL;

	if (crp == NULL || crp->crp_callback == NULL || crp->crp_desc == NULL) {
		error = EINVAL;
		goto out;
	}

	for (crd = crp->crp_desc; crd != NULL; crd = crd->crd_next) {
		switch (crd->crd_alg) {
		case CRYPTO_NULL_HMAC:
		case CRYPTO_MD5_HMAC:
		case CRYPTO_SHA1_HMAC:
		case CRYPTO_RIPEMD160_HMAC:
		case CRYPTO_SHA2_256_HMAC:
		case CRYPTO_SHA2_384_HMAC:
		case CRYPTO_SHA2_512_HMAC:
			if (maccrd != NULL) {
				error = EINVAL;
				goto out;
			}
			maccrd = crd;
			break;
		case CRYPTO_AES_CBC:
			if (enccrd != NULL) {
				error = EINVAL;
				goto out;
			}
			enccrd = crd;
			break;
		default:
			return (EINVAL);
		}
	}
	if (enccrd == NULL || (enccrd->crd_len % AES_BLOCK_LEN) != 0) {
		error = EINVAL;
		goto out;
	}

	mtx_lock(&sc->sc_sessions_mtx);
	TAILQ_FOREACH(ses, &sc->sc_sessions, ses_next) {
		if (ses->ses_id == (crp->crp_sid & 0xffffffff))
			break;
	}
	mtx_unlock(&sc->sc_sessions_mtx);
	if (ses == NULL) {
		error = EINVAL;
		goto out;
	}

	buf = malloc(enccrd->crd_len + 16, M_DEVBUF, M_NOWAIT);
	if (buf == NULL) {
		error = ENOMEM;
		goto out;
	}
	/* Buffer has to be 16 bytes aligned. */
	abuf = buf + 16 - ((uintptr_t)buf % 16);

	if ((enccrd->crd_flags & CRD_F_KEY_EXPLICIT) != 0)
		padlock_setup_enckey(ses, enccrd->crd_key, enccrd->crd_klen);
	if (maccrd != NULL && (maccrd->crd_flags & CRD_F_KEY_EXPLICIT) != 0)
		padlock_setup_mackey(ses, maccrd->crd_key, maccrd->crd_klen);

	cw = &ses->ses_cw;
	cw->cw_filler0 = 0;
	cw->cw_filler1 = 0;
	cw->cw_filler2 = 0;
	cw->cw_filler3 = 0;
	if ((enccrd->crd_flags & CRD_F_ENCRYPT) != 0) {
		cw->cw_direction = PADLOCK_DIRECTION_ENCRYPT;
		key = ses->ses_ekey;
		if ((enccrd->crd_flags & CRD_F_IV_EXPLICIT) != 0)
			bcopy(enccrd->crd_iv, ses->ses_iv, 16);

		if ((enccrd->crd_flags & CRD_F_IV_PRESENT) == 0) {
			crypto_copyback(crp->crp_flags, crp->crp_buf,
			    enccrd->crd_inject, AES_BLOCK_LEN, ses->ses_iv);
		}
	} else {
		cw->cw_direction = PADLOCK_DIRECTION_DECRYPT;
		key = ses->ses_dkey;
		if ((enccrd->crd_flags & CRD_F_IV_EXPLICIT) != 0)
			bcopy(enccrd->crd_iv, ses->ses_iv, AES_BLOCK_LEN);
		else {
			crypto_copydata(crp->crp_flags, crp->crp_buf,
			    enccrd->crd_inject, AES_BLOCK_LEN, ses->ses_iv);
		}
	}

	/* Perform data authentication if requested before encryption. */
	if (maccrd != NULL && maccrd->crd_next == enccrd) {
		error = padlock_authcompute(ses, maccrd, crp->crp_buf,
		    crp->crp_flags);
		if (error != 0)
			goto out;
	}

	crypto_copydata(crp->crp_flags, crp->crp_buf, enccrd->crd_skip,
	    enccrd->crd_len, abuf);

	padlock_cbc(abuf, abuf, enccrd->crd_len / 16, key, cw, ses->ses_iv);

	crypto_copyback(crp->crp_flags, crp->crp_buf, enccrd->crd_skip,
	    enccrd->crd_len, abuf);

	/* Perform data authentication if requested after encryption. */
	if (maccrd != NULL && enccrd->crd_next == maccrd) {
		error = padlock_authcompute(ses, maccrd, crp->crp_buf,
		    crp->crp_flags);
		if (error != 0)
			goto out;
	}

	/* copy out last block for use as next session IV */
	if ((enccrd->crd_flags & CRD_F_ENCRYPT) != 0) {
		crypto_copydata(crp->crp_flags, crp->crp_buf,
		    enccrd->crd_skip + enccrd->crd_len - AES_BLOCK_LEN,
		    AES_BLOCK_LEN, ses->ses_iv);
	}

out:
	if (buf != NULL) {
		bzero(buf, enccrd->crd_len + 16);
		free(buf, M_DEVBUF);
	}
	crp->crp_etype = error;
	crypto_done(crp);
	return (error);
}

static int
padlock_modevent(module_t mod, int type, void *unused __unused)
{
	int error;

	error = EOPNOTSUPP;
	switch (type) {
	case MOD_LOAD:
		error = padlock_init();
		break;
	case MOD_UNLOAD:
		error = padlock_destroy();
		break;
	}
	return (error);
}

static moduledata_t padlock_mod = {
	"padlock",
	padlock_modevent,
	0
};
DECLARE_MODULE(padlock, padlock_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
MODULE_VERSION(padlock, 1);
MODULE_DEPEND(padlock, crypto, 1, 1, 1);