kernel: Remove some unneeded NULL checks after kmalloc() with M_WAITOK.

[dragonfly.git] / sys / opencrypto / cryptodev.c

/*	$FreeBSD: src/sys/opencrypto/cryptodev.c,v 1.41 2009/09/04 09:48:18 pjd Exp $	*/
/*	$OpenBSD: cryptodev.c,v 1.52 2002/06/19 07:22:46 deraadt Exp $	*/

/*-
 * Copyright (c) 2001 Theo de Raadt
 * Copyright (c) 2002-2006 Sam Leffler, Errno Consulting
 *
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * Effort sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F30602-01-2-0537.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/device.h>
#include <sys/mbuf.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/errno.h>
#include <sys/uio.h>
#include <sys/random.h>
#include <sys/conf.h>
#include <sys/module.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/proc.h>

#include <sys/file2.h>
#include <sys/thread2.h>
#include <sys/mplock2.h>

#include <opencrypto/cryptodev.h>
#include <opencrypto/xform.h>

struct csession {
	TAILQ_ENTRY(csession) next;
	u_int64_t	sid;
	u_int32_t	ses;
	struct lock	lock;

	u_int32_t	cipher;
	struct enc_xform *txform;
	u_int32_t	mac;
	struct auth_hash *thash;

	caddr_t		key;
	int		keylen;
	u_char		tmp_iv[EALG_MAX_BLOCK_LEN];

	caddr_t		mackey;
	int		mackeylen;

	struct iovec	iovec;
	struct uio	uio;
	int		error;
};

struct fcrypt {
	TAILQ_HEAD(csessionlist, csession) csessions;
	int		sesn;
};

static	int cryptof_rw(struct file *fp, struct uio *uio,
		    struct ucred *cred, int flags);
static	int cryptof_ioctl(struct file *, u_long, caddr_t,
		    struct ucred *, struct sysmsg *);
static	int cryptof_kqfilter(struct file *, struct knote *);
static	int cryptof_stat(struct file *, struct stat *, struct ucred *);
static	int cryptof_close(struct file *);

static struct fileops cryptofops = {
    .fo_read = cryptof_rw,
    .fo_write = cryptof_rw,
    .fo_ioctl = cryptof_ioctl,
    .fo_kqfilter = cryptof_kqfilter,
    .fo_stat = cryptof_stat,
    .fo_close = cryptof_close,
    .fo_shutdown = nofo_shutdown
};

static struct csession *csefind(struct fcrypt *, u_int);
static int csedelete(struct fcrypt *, struct csession *);
static struct csession *cseadd(struct fcrypt *, struct csession *);
static struct csession *csecreate(struct fcrypt *, u_int64_t, caddr_t,
    u_int64_t, caddr_t, u_int64_t, u_int32_t, u_int32_t, struct enc_xform *,
    struct auth_hash *);
static int csefree(struct csession *);

static	int cryptodev_op(struct csession *, struct crypt_op *, struct ucred *);
static	int cryptodev_key(struct crypt_kop *);
static	int cryptodev_find(struct crypt_find_op *);

static int
cryptof_rw(
	struct file *fp,
	struct uio *uio,
	struct ucred *active_cred,
	int flags)
{
	return (EIO);
}

/*
 * Check a crypto identifier to see if it requested
 * a software device/driver.  This can be done either
 * by device name/class or through search constraints.
 */
static int
checkforsoftware(int crid)
{
	if (crid & CRYPTOCAP_F_SOFTWARE)
		return EINVAL;		/* XXX */
	if ((crid & CRYPTOCAP_F_HARDWARE) == 0 &&
	    (crypto_getcaps(crid) & CRYPTOCAP_F_HARDWARE) == 0)
		return EINVAL;		/* XXX */
	return 0;
}

/* ARGSUSED */
static int
cryptof_ioctl(struct file *fp, u_long cmd, caddr_t data,
	      struct ucred *cred, struct sysmsg *msg)
{
#define	SES2(p)	((struct session2_op *)p)
	struct cryptoini cria, crie;
	struct fcrypt *fcr = fp->f_data;
	struct csession *cse;
	struct session_op *sop;
	struct crypt_op *cop;
	struct enc_xform *txform = NULL;
	struct auth_hash *thash = NULL;
	struct crypt_kop *kop;
	u_int64_t sid;
	u_int32_t ses;
	int error = 0, crid;

	switch (cmd) {
	case CIOCGSESSION:
	case CIOCGSESSION2:
		sop = (struct session_op *)data;
		switch (sop->cipher) {
		case 0:
			break;
		case CRYPTO_DES_CBC:
			txform = &enc_xform_des;
			break;
		case CRYPTO_3DES_CBC:
			txform = &enc_xform_3des;
			break;
		case CRYPTO_BLF_CBC:
			txform = &enc_xform_blf;
			break;
		case CRYPTO_CAST_CBC:
			txform = &enc_xform_cast5;
			break;
		case CRYPTO_SKIPJACK_CBC:
			txform = &enc_xform_skipjack;
			break;
		case CRYPTO_AES_CBC:
			txform = &enc_xform_rijndael128;
			break;
		case CRYPTO_AES_XTS:
			txform = &enc_xform_aes_xts;
			break;
		case CRYPTO_AES_CTR:
			txform = &enc_xform_aes_ctr;
			break;		
		case CRYPTO_NULL_CBC:
			txform = &enc_xform_null;
			break;
		case CRYPTO_ARC4:
			txform = &enc_xform_arc4;
			break;
		case CRYPTO_CAMELLIA_CBC:
			txform = &enc_xform_camellia;
			break;
		case CRYPTO_TWOFISH_CBC:
			txform = &enc_xform_twofish;
			break;
		case CRYPTO_SERPENT_CBC:
			txform = &enc_xform_serpent;
			break;
		case CRYPTO_TWOFISH_XTS:
			txform = &enc_xform_twofish_xts;
			break;
		case CRYPTO_SERPENT_XTS:
			txform = &enc_xform_serpent_xts;
			break;
		default:
			return (EINVAL);
		}

		switch (sop->mac) {
		case 0:
			break;
		case CRYPTO_MD5_HMAC:
			thash = &auth_hash_hmac_md5;
			break;
		case CRYPTO_SHA1_HMAC:
			thash = &auth_hash_hmac_sha1;
			break;
		case CRYPTO_SHA2_256_HMAC:
			thash = &auth_hash_hmac_sha2_256;
			break;
		case CRYPTO_SHA2_384_HMAC:
			thash = &auth_hash_hmac_sha2_384;
			break;
		case CRYPTO_SHA2_512_HMAC:
			thash = &auth_hash_hmac_sha2_512;
			break;
		case CRYPTO_RIPEMD160_HMAC:
			thash = &auth_hash_hmac_ripemd_160;
			break;
#ifdef notdef
		case CRYPTO_MD5:
			thash = &auth_hash_md5;
			break;
		case CRYPTO_SHA1:
			thash = &auth_hash_sha1;
			break;
#endif
		case CRYPTO_NULL_HMAC:
			thash = &auth_hash_null;
			break;
		default:
			return (EINVAL);
		}

		bzero(&crie, sizeof(crie));
		bzero(&cria, sizeof(cria));

		if (txform) {
			crie.cri_alg = txform->type;
			crie.cri_klen = sop->keylen * 8;
			if (sop->keylen > txform->maxkey ||
			    sop->keylen < txform->minkey) {
				error = EINVAL;
				goto bail;
			}

			crie.cri_key = kmalloc(crie.cri_klen / 8,
			    M_XDATA, M_WAITOK);
			if ((error = copyin(sop->key, crie.cri_key,
			    crie.cri_klen / 8)))
				goto bail;
			if (thash)
				crie.cri_next = &cria;
		}

		if (thash) {
			cria.cri_alg = thash->type;
			cria.cri_klen = sop->mackeylen * 8;
			if (sop->mackeylen != thash->keysize) {
				error = EINVAL;
				goto bail;
			}

			if (cria.cri_klen) {
				cria.cri_key = kmalloc(cria.cri_klen / 8,
				    M_XDATA, M_WAITOK);
				if ((error = copyin(sop->mackey, cria.cri_key,
				    cria.cri_klen / 8)))
					goto bail;
			}
		}

		/* NB: CIOGSESSION2 has the crid */
		if (cmd == CIOCGSESSION2) {
			crid = SES2(sop)->crid;
			error = checkforsoftware(crid);
			if (error)
				goto bail;
		} else {
			crid = CRYPTOCAP_F_HARDWARE;
			if (crypto_devallowsoft)
				crid |= CRYPTOCAP_F_SOFTWARE;
		}
		error = crypto_newsession(&sid, (txform ? &crie : &cria), crid);
		if (error)
			goto bail;

		cse = csecreate(fcr, sid, crie.cri_key, crie.cri_klen,
		    cria.cri_key, cria.cri_klen, sop->cipher, sop->mac, txform,
		    thash);

		if (cse == NULL) {
			crypto_freesession(sid);
			error = EINVAL;
			goto bail;
		}
		sop->ses = cse->ses;
		if (cmd == CIOCGSESSION2) {
			/* return hardware/driver id */
			SES2(sop)->crid = CRYPTO_SESID2HID(cse->sid);
		}
bail:
		if (error) {
			if (crie.cri_key) {
				bzero(crie.cri_key, crie.cri_klen / 8);
				kfree(crie.cri_key, M_XDATA);
			}
			if (cria.cri_key) {
				bzero(crie.cri_key, crie.cri_klen / 8);
				kfree(cria.cri_key, M_XDATA);
			}
		}
		break;
	case CIOCFSESSION:
		ses = *(u_int32_t *)data;
		cse = csefind(fcr, ses);
		if (cse == NULL)
			return (EINVAL);
		csedelete(fcr, cse);
		error = csefree(cse);
		break;
	case CIOCCRYPT:
		cop = (struct crypt_op *)data;
		cse = csefind(fcr, cop->ses);
		if (cse == NULL)
			return (EINVAL);
		error = cryptodev_op(cse, cop, cred);
		break;
	case CIOCKEY:
	case CIOCKEY2:
		if (!crypto_userasymcrypto)
			return (EPERM);		/* XXX compat? */
		get_mplock();
		kop = (struct crypt_kop *)data;
		if (cmd == CIOCKEY) {
			/* NB: crypto core enforces s/w driver use */
			kop->crk_crid =
			    CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE;
		}
		error = cryptodev_key(kop);
		rel_mplock();
		break;
	case CIOCASYMFEAT:
		if (!crypto_userasymcrypto) {
			/*
			 * NB: if user asym crypto operations are
			 * not permitted return "no algorithms"
			 * so well-behaved applications will just
			 * fallback to doing them in software.
			 */
			*(int *)data = 0;
		} else
			error = crypto_getfeat((int *)data);
		break;
	case CIOCFINDDEV:
		error = cryptodev_find((struct crypt_find_op *)data);
		break;
	default:
		error = EINVAL;
		break;
	}
	return (error);
#undef SES2
}

static int cryptodev_cb(void *);


static int
cryptodev_op(struct csession *cse, struct crypt_op *cop,
    struct ucred *active_cred)
{
	struct cryptop *crp = NULL;
	struct cryptodesc *crde = NULL, *crda = NULL;
	int error;

	if (cop->len > 256*1024-4)
		return (E2BIG);

	if (cse->txform) {
		if (cop->len == 0 || (cop->len % cse->txform->blocksize) != 0)
			return (EINVAL);
	}

	bzero(&cse->uio, sizeof(cse->uio));
	cse->uio.uio_iov = &cse->iovec;
	cse->uio.uio_iovcnt = 1;
	cse->uio.uio_offset = 0;
	cse->uio.uio_resid = cop->len;
	cse->uio.uio_segflg = UIO_SYSSPACE;
	cse->uio.uio_rw = UIO_WRITE;
	/* XXX: not sure, was td, now curthread? */
	cse->uio.uio_td = curthread;
	cse->uio.uio_iov[0].iov_len = cop->len;
	if (cse->thash) {
		cse->uio.uio_iov[0].iov_len += cse->thash->hashsize;
		cse->uio.uio_resid += cse->thash->hashsize;
	}
	cse->uio.uio_iov[0].iov_base = kmalloc(cse->uio.uio_iov[0].iov_len,
	    M_XDATA, M_WAITOK);

	crp = crypto_getreq((cse->txform != NULL) + (cse->thash != NULL));
	if (crp == NULL) {
		error = ENOMEM;
		goto bail;
	}

	if (cse->thash) {
		crda = crp->crp_desc;
		if (cse->txform)
			crde = crda->crd_next;
	} else {
		if (cse->txform)
			crde = crp->crp_desc;
		else {
			error = EINVAL;
			goto bail;
		}
	}

	if ((error = copyin(cop->src, cse->uio.uio_iov[0].iov_base, cop->len)))
		goto bail;

	if (crda) {
		crda->crd_skip = 0;
		crda->crd_len = cop->len;
		crda->crd_inject = cop->len;

		crda->crd_alg = cse->mac;
		crda->crd_key = cse->mackey;
		crda->crd_klen = cse->mackeylen * 8;
	}

	if (crde) {
		if (cop->op == COP_ENCRYPT)
			crde->crd_flags |= CRD_F_ENCRYPT;
		else
			crde->crd_flags &= ~CRD_F_ENCRYPT;
		crde->crd_len = cop->len;
		crde->crd_inject = 0;

		crde->crd_alg = cse->cipher;
		crde->crd_key = cse->key;
		crde->crd_klen = cse->keylen * 8;
	}

	crp->crp_ilen = cop->len;
	crp->crp_flags = CRYPTO_F_IOV | CRYPTO_F_CBIMM
		       | (cop->flags & COP_F_BATCH);
	crp->crp_buf = (caddr_t)&cse->uio;
	crp->crp_callback = (int (*) (struct cryptop *)) cryptodev_cb;
	crp->crp_sid = cse->sid;
	crp->crp_opaque = (void *)cse;

	if (cop->iv) {
		if (crde == NULL) {
			error = EINVAL;
			goto bail;
		}
		if (cse->cipher == CRYPTO_ARC4) { /* XXX use flag? */
			error = EINVAL;
			goto bail;
		}
		if ((error = copyin(cop->iv, cse->tmp_iv, cse->txform->blocksize)))
			goto bail;
		bcopy(cse->tmp_iv, crde->crd_iv, cse->txform->blocksize);
		crde->crd_flags |= CRD_F_IV_EXPLICIT | CRD_F_IV_PRESENT;
		crde->crd_skip = 0;
	} else if (cse->cipher == CRYPTO_ARC4) { /* XXX use flag? */
		crde->crd_skip = 0;
	} else if (crde) {
		crde->crd_flags |= CRD_F_IV_PRESENT;
		crde->crd_skip = cse->txform->blocksize;
		crde->crd_len -= cse->txform->blocksize;
	}

	if (cop->mac && crda == NULL) {
		error = EINVAL;
		goto bail;
	}

again:
	/*
	 * Let the dispatch run unlocked, then, interlock against the
	 * callback before checking if the operation completed and going
	 * to sleep.  This insures drivers don't inherit our lock which
	 * results in a lock order reversal between crypto_dispatch forced
	 * entry and the crypto_done callback into us.
	 */
	error = crypto_dispatch(crp);
	lockmgr(&cse->lock, LK_EXCLUSIVE);
	if (error == 0 && (crp->crp_flags & CRYPTO_F_DONE) == 0)
		error = lksleep(crp, &cse->lock, 0, "crydev", 0);
	lockmgr(&cse->lock, LK_RELEASE);

	if (error != 0)
		goto bail;

	if (crp->crp_etype == EAGAIN) {
		crp->crp_etype = 0;
		crp->crp_flags &= ~CRYPTO_F_DONE;
		goto again;
	}

	if (crp->crp_etype != 0) {
		error = crp->crp_etype;
		goto bail;
	}

	if (cse->error) {
		error = cse->error;
		goto bail;
	}

	if (cop->dst &&
	    (error = copyout(cse->uio.uio_iov[0].iov_base, cop->dst, cop->len)))
		goto bail;

	if (cop->mac &&
	    (error = copyout((caddr_t)cse->uio.uio_iov[0].iov_base + cop->len,
	    cop->mac, cse->thash->hashsize)))
		goto bail;

bail:
	if (crp)
		crypto_freereq(crp);
	if (cse->uio.uio_iov[0].iov_base)
		kfree(cse->uio.uio_iov[0].iov_base, M_XDATA);

	return (error);
}

static int
cryptodev_cb(void *op)
{
	struct cryptop *crp = (struct cryptop *) op;
	struct csession *cse = (struct csession *)crp->crp_opaque;

	lockmgr(&cse->lock, LK_EXCLUSIVE);
	cse->error = crp->crp_etype;
	wakeup_one(crp);
	lockmgr(&cse->lock, LK_RELEASE);
	return (0);
}

static int
cryptodevkey_cb(void *op)
{
	struct cryptkop *krp = (struct cryptkop *) op;

	wakeup_one(krp);
	return (0);
}

static int
cryptodev_key(struct crypt_kop *kop)
{
	struct cryptkop *krp = NULL;
	int error = EINVAL;
	int in, out, size, i;

	if (kop->crk_iparams + kop->crk_oparams > CRK_MAXPARAM) {
		return (EFBIG);
	}

	in = kop->crk_iparams;
	out = kop->crk_oparams;
	switch (kop->crk_op) {
	case CRK_MOD_EXP:
		if (in == 3 && out == 1)
			break;
		return (EINVAL);
	case CRK_MOD_EXP_CRT:
		if (in == 6 && out == 1)
			break;
		return (EINVAL);
	case CRK_DSA_SIGN:
		if (in == 5 && out == 2)
			break;
		return (EINVAL);
	case CRK_DSA_VERIFY:
		if (in == 7 && out == 0)
			break;
		return (EINVAL);
	case CRK_DH_COMPUTE_KEY:
		if (in == 3 && out == 1)
			break;
		return (EINVAL);
	default:
		return (EINVAL);
	}

	krp = (struct cryptkop *)kmalloc(sizeof *krp, M_XDATA, M_WAITOK | M_ZERO);
	krp->krp_op = kop->crk_op;
	krp->krp_status = kop->crk_status;
	krp->krp_iparams = kop->crk_iparams;
	krp->krp_oparams = kop->crk_oparams;
	krp->krp_crid = kop->crk_crid;
	krp->krp_status = 0;
	krp->krp_callback = (int (*) (struct cryptkop *)) cryptodevkey_cb;

	for (i = 0; i < CRK_MAXPARAM; i++) {
		if (kop->crk_param[i].crp_nbits > 65536)
			/* Limit is the same as in OpenBSD */
			goto fail;
		krp->krp_param[i].crp_nbits = kop->crk_param[i].crp_nbits;
	}
	for (i = 0; i < krp->krp_iparams + krp->krp_oparams; i++) {
		size = (krp->krp_param[i].crp_nbits + 7) / 8;
		if (size == 0)
			continue;
		krp->krp_param[i].crp_p = kmalloc(size, M_XDATA, M_WAITOK);
		if (i >= krp->krp_iparams)
			continue;
		error = copyin(kop->crk_param[i].crp_p, krp->krp_param[i].crp_p, size);
		if (error)
			goto fail;
	}

	error = crypto_kdispatch(krp);
	if (error)
		goto fail;
	error = tsleep(krp, 0, "crydev", 0);
	if (error) {
		/* XXX can this happen?  if so, how do we recover? */
		goto fail;
	}
	
	kop->crk_crid = krp->krp_crid;		/* device that did the work */
	if (krp->krp_status != 0) {
		error = krp->krp_status;
		goto fail;
	}

	for (i = krp->krp_iparams; i < krp->krp_iparams + krp->krp_oparams; i++) {
		size = (krp->krp_param[i].crp_nbits + 7) / 8;
		if (size == 0)
			continue;
		error = copyout(krp->krp_param[i].crp_p, kop->crk_param[i].crp_p, size);
		if (error)
			goto fail;
	}

fail:
	if (krp) {
		kop->crk_status = krp->krp_status;
		for (i = 0; i < CRK_MAXPARAM; i++) {
			if (krp->krp_param[i].crp_p) {
				bzero(krp->krp_param[i].crp_p,
				    (krp->krp_param[i].crp_nbits + 7) / 8);
				kfree(krp->krp_param[i].crp_p, M_XDATA);
			}
		}
		kfree(krp, M_XDATA);
	}
	return (error);
}

static int
cryptodev_find(struct crypt_find_op *find)
{
	device_t dev;

	if (find->crid != -1) {
		dev = crypto_find_device_byhid(find->crid);
		if (dev == NULL)
			return (ENOENT);
		strlcpy(find->name, device_get_nameunit(dev),
		    sizeof(find->name));
	} else {
		find->crid = crypto_find_driver(find->name);
		if (find->crid == -1)
			return (ENOENT);
	}
	return (0);
}

/*
 * MPSAFE
 */
static int
cryptof_kqfilter(struct file *fp, struct knote *kn)
{

	return (0);
}

/*
 * MPSAFE
 */
static int
cryptof_stat(struct file *fp, struct stat *sb, struct ucred *cred)
{
	return (EOPNOTSUPP);
}

/*
 * MPALMOSTSAFE - acquires mplock
 */
static int
cryptof_close(struct file *fp)
{
	struct fcrypt *fcr = fp->f_data;
	struct csession *cse;

	get_mplock();
	fcr = (struct fcrypt *)fp->f_data;
	while ((cse = TAILQ_FIRST(&fcr->csessions))) {
		TAILQ_REMOVE(&fcr->csessions, cse, next);
		(void)csefree(cse);
	}
	fp->f_data = NULL;
	rel_mplock();

	kfree(fcr, M_XDATA);
	return (0);
}

static struct csession *
csefind(struct fcrypt *fcr, u_int ses)
{
	struct csession *cse;

	TAILQ_FOREACH(cse, &fcr->csessions, next)
		if (cse->ses == ses)
			return (cse);
	return (NULL);
}

static int
csedelete(struct fcrypt *fcr, struct csession *cse_del)
{
	struct csession *cse;

	TAILQ_FOREACH(cse, &fcr->csessions, next) {
		if (cse == cse_del) {
			TAILQ_REMOVE(&fcr->csessions, cse, next);
			return (1);
		}
	}
	return (0);
}
	
static struct csession *
cseadd(struct fcrypt *fcr, struct csession *cse)
{
	TAILQ_INSERT_TAIL(&fcr->csessions, cse, next);
	cse->ses = fcr->sesn++;
	return (cse);
}

struct csession *
csecreate(struct fcrypt *fcr, u_int64_t sid, caddr_t key, u_int64_t keylen,
    caddr_t mackey, u_int64_t mackeylen, u_int32_t cipher, u_int32_t mac,
    struct enc_xform *txform, struct auth_hash *thash)
{
	struct csession *cse;

	cse = kmalloc(sizeof(struct csession), M_XDATA, M_WAITOK | M_ZERO);
	lockinit(&cse->lock, "cryptodev", 0, LK_CANRECURSE);
	cse->key = key;
	cse->keylen = keylen/8;
	cse->mackey = mackey;
	cse->mackeylen = mackeylen/8;
	cse->sid = sid;
	cse->cipher = cipher;
	cse->mac = mac;
	cse->txform = txform;
	cse->thash = thash;
	cseadd(fcr, cse);
	return (cse);
}

static int
csefree(struct csession *cse)
{
	int error;

	error = crypto_freesession(cse->sid);
	lockuninit(&cse->lock);
	if (cse->key)
		kfree(cse->key, M_XDATA);
	if (cse->mackey)
		kfree(cse->mackey, M_XDATA);
	kfree(cse, M_XDATA);
	return (error);
}

static int
cryptoopen(struct dev_open_args *ap)
{
	return (0);
}

static int
cryptoread(struct dev_read_args *ap)
{
	return (EIO);
}

static int
cryptowrite(struct dev_write_args *ap)
{
	return (EIO);
}

static int
cryptoioctl(struct dev_ioctl_args *ap)
{
	struct thread *td = curthread;
	struct file *f;
	struct fcrypt *fcr;
	int fd, error;

	switch (ap->a_cmd) {
	case CRIOGET:
		fcr = kmalloc(sizeof(struct fcrypt), M_XDATA, M_WAITOK);
		TAILQ_INIT(&fcr->csessions);
		fcr->sesn = 0;

		KKASSERT(td->td_lwp);
		error = falloc(td->td_lwp, &f, &fd);

		if (error) {
			kfree(fcr, M_XDATA);
			return (error);
		}
		/* falloc automatically provides an extra reference to 'f'. */
		f->f_flag = FREAD | FWRITE;
		f->f_type = DTYPE_CRYPTO;
		f->f_ops = &cryptofops;
		f->f_data = fcr;
		fsetfd(td->td_proc->p_fd, f, fd);
		*(u_int32_t *)ap->a_data = fd;
		fdrop(f);

		break;
	case CRIOFINDDEV:
		error = cryptodev_find((struct crypt_find_op *)ap->a_data);
		break;
	case CRIOASYMFEAT:
		error = crypto_getfeat((int *)ap->a_data);
		break;
	default:
		error = EINVAL;
		break;
	}
	return (error);
}

static struct dev_ops crypto_ops = {
	{ "crypto", 0, D_MPSAFE },
	.d_open =	cryptoopen,
	.d_read =	cryptoread,
	.d_write =	cryptowrite,
	.d_ioctl =	cryptoioctl,
};

/*
 * Initialization code, both for static and dynamic loading.
 */
static int
cryptodev_modevent(module_t mod, int type, void *unused)
{
	switch (type) {
	case MOD_LOAD:
		if (bootverbose)
			kprintf("crypto: <crypto device>\n");
		make_dev(&crypto_ops, 0, UID_ROOT, GID_WHEEL,
			 0666, "crypto");
		return 0;
	case MOD_UNLOAD:
		/*XXX disallow if active sessions */
		//dev_ops_remove(&crypto_ops, 0, 0);
		dev_ops_remove_all(&crypto_ops);
		return 0;
	}
	return EINVAL;
}

static moduledata_t cryptodev_mod = {
	"cryptodev",
	cryptodev_modevent,
	0
};
MODULE_VERSION(cryptodev, 1);
DECLARE_MODULE(cryptodev, cryptodev_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_DEPEND(cryptodev, crypto, 1, 1, 1);
MODULE_DEPEND(cryptodev, zlib, 1, 1, 1);