[linux.git] / drivers / block / cryptoloop.c

/*
   Linux loop encryption enabling module

   Copyright (C)  2002 Herbert Valerio Riedel <[email protected]>
   Copyright (C)  2003 Fruhwirth Clemens <[email protected]>

   This module is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This module is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this module; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>

#include <linux/init.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/blkdev.h>
#include <linux/loop.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("loop blockdevice transferfunction adaptor / CryptoAPI");
MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>");

#define LOOP_IV_SECTOR_BITS 9
#define LOOP_IV_SECTOR_SIZE (1 << LOOP_IV_SECTOR_BITS)

static int
cryptoloop_init(struct loop_device *lo, const struct loop_info64 *info)
{
	int err = -EINVAL;
	char cms[LO_NAME_SIZE];			/* cipher-mode string */
	char *cipher;
	char *mode;
	char *cmsp = cms;			/* c-m string pointer */
	struct crypto_tfm *tfm = NULL;

	/* encryption breaks for non sector aligned offsets */

	if (info->lo_offset % LOOP_IV_SECTOR_SIZE)
		goto out;

	strncpy(cms, info->lo_crypt_name, LO_NAME_SIZE);
	cms[LO_NAME_SIZE - 1] = 0;
	cipher = strsep(&cmsp, "-");
	mode = strsep(&cmsp, "-");

	if (mode == NULL || strcmp(mode, "cbc") == 0)
		tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_CBC |
					       CRYPTO_TFM_REQ_MAY_SLEEP);
	else if (strcmp(mode, "ecb") == 0)
		tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_ECB |
					       CRYPTO_TFM_REQ_MAY_SLEEP);
	if (tfm == NULL)
		return -EINVAL;

	err = tfm->crt_u.cipher.cit_setkey(tfm, info->lo_encrypt_key,
					   info->lo_encrypt_key_size);
	
	if (err != 0)
		goto out_free_tfm;

	lo->key_data = tfm;
	return 0;

 out_free_tfm:
	crypto_free_tfm(tfm);

 out:
	return err;
}


typedef int (*encdec_ecb_t)(struct crypto_tfm *tfm,
			struct scatterlist *sg_out,
			struct scatterlist *sg_in,
			unsigned int nsg);


static int
cryptoloop_transfer_ecb(struct loop_device *lo, int cmd,
			struct page *raw_page, unsigned raw_off,
			struct page *loop_page, unsigned loop_off,
			int size, sector_t IV)
{
	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
	struct scatterlist sg_out = { NULL, };
	struct scatterlist sg_in = { NULL, };

	encdec_ecb_t encdecfunc;
	struct page *in_page, *out_page;
	unsigned in_offs, out_offs;

	if (cmd == READ) {
		in_page = raw_page;
		in_offs = raw_off;
		out_page = loop_page;
		out_offs = loop_off;
		encdecfunc = tfm->crt_u.cipher.cit_decrypt;
	} else {
		in_page = loop_page;
		in_offs = loop_off;
		out_page = raw_page;
		out_offs = raw_off;
		encdecfunc = tfm->crt_u.cipher.cit_encrypt;
	}

	while (size > 0) {
		const int sz = min(size, LOOP_IV_SECTOR_SIZE);

		sg_in.page = in_page;
		sg_in.offset = in_offs;
		sg_in.length = sz;

		sg_out.page = out_page;
		sg_out.offset = out_offs;
		sg_out.length = sz;

		encdecfunc(tfm, &sg_out, &sg_in, sz);

		size -= sz;
		in_offs += sz;
		out_offs += sz;
	}

	return 0;
}

typedef int (*encdec_cbc_t)(struct crypto_tfm *tfm,
			struct scatterlist *sg_out,
			struct scatterlist *sg_in,
			unsigned int nsg, u8 *iv);

static int
cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
			struct page *raw_page, unsigned raw_off,
			struct page *loop_page, unsigned loop_off,
			int size, sector_t IV)
{
	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
	struct scatterlist sg_out = { NULL, };
	struct scatterlist sg_in = { NULL, };

	encdec_cbc_t encdecfunc;
	struct page *in_page, *out_page;
	unsigned in_offs, out_offs;

	if (cmd == READ) {
		in_page = raw_page;
		in_offs = raw_off;
		out_page = loop_page;
		out_offs = loop_off;
		encdecfunc = tfm->crt_u.cipher.cit_decrypt_iv;
	} else {
		in_page = loop_page;
		in_offs = loop_off;
		out_page = raw_page;
		out_offs = raw_off;
		encdecfunc = tfm->crt_u.cipher.cit_encrypt_iv;
	}

	while (size > 0) {
		const int sz = min(size, LOOP_IV_SECTOR_SIZE);
		u32 iv[4] = { 0, };
		iv[0] = cpu_to_le32(IV & 0xffffffff);

		sg_in.page = in_page;
		sg_in.offset = in_offs;
		sg_in.length = sz;

		sg_out.page = out_page;
		sg_out.offset = out_offs;
		sg_out.length = sz;

		encdecfunc(tfm, &sg_out, &sg_in, sz, (u8 *)iv);

		IV++;
		size -= sz;
		in_offs += sz;
		out_offs += sz;
	}

	return 0;
}

static int
cryptoloop_transfer(struct loop_device *lo, int cmd,
		    struct page *raw_page, unsigned raw_off,
		    struct page *loop_page, unsigned loop_off,
		    int size, sector_t IV)
{
	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_ECB)
	{
		lo->transfer = cryptoloop_transfer_ecb;
		return cryptoloop_transfer_ecb(lo, cmd, raw_page, raw_off,
					       loop_page, loop_off, size, IV);
	}	
	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_CBC)
	{	
		lo->transfer = cryptoloop_transfer_cbc;
		return cryptoloop_transfer_cbc(lo, cmd, raw_page, raw_off,
					       loop_page, loop_off, size, IV);
	}
	
	/*  This is not supposed to happen */

	printk( KERN_ERR "cryptoloop: unsupported cipher mode in cryptoloop_transfer!\n");
	return -EINVAL;
}

static int
cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg)
{
	return -EINVAL;
}

static int
cryptoloop_release(struct loop_device *lo)
{
	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
	if (tfm != NULL) {
		crypto_free_tfm(tfm);
		lo->key_data = NULL;
		return 0;
	}
	printk(KERN_ERR "cryptoloop_release(): tfm == NULL?\n");
	return -EINVAL;
}

static struct loop_func_table cryptoloop_funcs = {
	.number = LO_CRYPT_CRYPTOAPI,
	.init = cryptoloop_init,
	.ioctl = cryptoloop_ioctl,
	.transfer = cryptoloop_transfer,
	.release = cryptoloop_release,
	.owner = THIS_MODULE
};

static int __init
init_cryptoloop(void)
{
	int rc = loop_register_transfer(&cryptoloop_funcs);

	if (rc)
		printk(KERN_ERR "cryptoloop: loop_register_transfer failed\n");
	return rc;
}

static void __exit
cleanup_cryptoloop(void)
{
	if (loop_unregister_transfer(LO_CRYPT_CRYPTOAPI))
		printk(KERN_ERR
			"cryptoloop: loop_unregister_transfer failed\n");
}

module_init(init_cryptoloop);
module_exit(cleanup_cryptoloop);
Commit	Line	Data
1da177e4 LT	1	/*
	2	Linux loop encryption enabling module
	3
	4	Copyright (C) 2002 Herbert Valerio Riedel <[email protected]>
	5	Copyright (C) 2003 Fruhwirth Clemens <[email protected]>
	6
	7	This module is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 2 of the License, or
	10	(at your option) any later version.
	11
	12	This module is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with this module; if not, write to the Free Software
	19	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	#include <linux/module.h>
	23
	24	#include <linux/init.h>
	25	#include <linux/string.h>
	26	#include <linux/crypto.h>
	27	#include <linux/blkdev.h>
	28	#include <linux/loop.h>
	29	#include <asm/semaphore.h>
	30	#include <asm/uaccess.h>
	31
	32	MODULE_LICENSE("GPL");
	33	MODULE_DESCRIPTION("loop blockdevice transferfunction adaptor / CryptoAPI");
	34	MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>");
	35
	36	#define LOOP_IV_SECTOR_BITS 9
	37	#define LOOP_IV_SECTOR_SIZE (1 << LOOP_IV_SECTOR_BITS)
	38
	39	static int
	40	cryptoloop_init(struct loop_device lo, const struct loop_info64 info)
	41	{
	42	int err = -EINVAL;
	43	char cms[LO_NAME_SIZE]; /* cipher-mode string */
	44	char *cipher;
	45	char *mode;
	46	char cmsp = cms; / c-m string pointer */
	47	struct crypto_tfm *tfm = NULL;
	48
	49	/* encryption breaks for non sector aligned offsets */
	50
	51	if (info->lo_offset % LOOP_IV_SECTOR_SIZE)
	52	goto out;
	53
	54	strncpy(cms, info->lo_crypt_name, LO_NAME_SIZE);
	55	cms[LO_NAME_SIZE - 1] = 0;
	56	cipher = strsep(&cmsp, "-");
	57	mode = strsep(&cmsp, "-");
	58
	59	if (mode == NULL \|\| strcmp(mode, "cbc") == 0)
eb6f1160 HX	60	tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_CBC \|
eb6f1160 HX	61	CRYPTO_TFM_REQ_MAY_SLEEP);
1da177e4	62	else if (strcmp(mode, "ecb") == 0)
eb6f1160 HX	63	tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_ECB \|
eb6f1160 HX	64	CRYPTO_TFM_REQ_MAY_SLEEP);
1da177e4 LT	65	if (tfm == NULL)
	66	return -EINVAL;
	67
	68	err = tfm->crt_u.cipher.cit_setkey(tfm, info->lo_encrypt_key,
	69	info->lo_encrypt_key_size);
	70
	71	if (err != 0)
	72	goto out_free_tfm;
	73
	74	lo->key_data = tfm;
	75	return 0;
	76
	77	out_free_tfm:
	78	crypto_free_tfm(tfm);
	79
	80	out:
	81	return err;
	82	}
	83
	84
	85	typedef int (encdec_ecb_t)(struct crypto_tfm tfm,
	86	struct scatterlist *sg_out,
	87	struct scatterlist *sg_in,
	88	unsigned int nsg);
	89
	90
	91	static int
	92	cryptoloop_transfer_ecb(struct loop_device *lo, int cmd,
	93	struct page *raw_page, unsigned raw_off,
	94	struct page *loop_page, unsigned loop_off,
	95	int size, sector_t IV)
	96	{
	97	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
	98	struct scatterlist sg_out = { NULL, };
	99	struct scatterlist sg_in = { NULL, };
	100
	101	encdec_ecb_t encdecfunc;
	102	struct page in_page, out_page;
	103	unsigned in_offs, out_offs;
	104
	105	if (cmd == READ) {
	106	in_page = raw_page;
	107	in_offs = raw_off;
	108	out_page = loop_page;
	109	out_offs = loop_off;
	110	encdecfunc = tfm->crt_u.cipher.cit_decrypt;
	111	} else {
	112	in_page = loop_page;
	113	in_offs = loop_off;
	114	out_page = raw_page;
	115	out_offs = raw_off;
	116	encdecfunc = tfm->crt_u.cipher.cit_encrypt;
	117	}
	118
	119	while (size > 0) {
	120	const int sz = min(size, LOOP_IV_SECTOR_SIZE);
	121
	122	sg_in.page = in_page;
	123	sg_in.offset = in_offs;
	124	sg_in.length = sz;
	125
	126	sg_out.page = out_page;
	127	sg_out.offset = out_offs;
	128	sg_out.length = sz;
129
130	encdecfunc(tfm, &sg_out, &sg_in, sz);
131
132	size -= sz;
133	in_offs += sz;
134	out_offs += sz;
135	}
136
137	return 0;
138	}
139
140	typedef int (encdec_cbc_t)(struct crypto_tfm tfm,
141	struct scatterlist *sg_out,
142	struct scatterlist *sg_in,
143	unsigned int nsg, u8 *iv);
144
145	static int
146	cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
147	struct page *raw_page, unsigned raw_off,
148	struct page *loop_page, unsigned loop_off,
149	int size, sector_t IV)
150	{
151	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
152	struct scatterlist sg_out = { NULL, };
153	struct scatterlist sg_in = { NULL, };
154
155	encdec_cbc_t encdecfunc;
156	struct page in_page, out_page;
157	unsigned in_offs, out_offs;
158
159	if (cmd == READ) {
160	in_page = raw_page;
161	in_offs = raw_off;
162	out_page = loop_page;
163	out_offs = loop_off;
164	encdecfunc = tfm->crt_u.cipher.cit_decrypt_iv;
165	} else {
166	in_page = loop_page;
167	in_offs = loop_off;
168	out_page = raw_page;
169	out_offs = raw_off;
170	encdecfunc = tfm->crt_u.cipher.cit_encrypt_iv;
171	}
172
173	while (size > 0) {
174	const int sz = min(size, LOOP_IV_SECTOR_SIZE);
175	u32 iv[4] = { 0, };
176	iv[0] = cpu_to_le32(IV & 0xffffffff);
177
178	sg_in.page = in_page;
179	sg_in.offset = in_offs;
180	sg_in.length = sz;
181
182	sg_out.page = out_page;
183	sg_out.offset = out_offs;
184	sg_out.length = sz;
185
186	encdecfunc(tfm, &sg_out, &sg_in, sz, (u8 *)iv);
187
188	IV++;
189	size -= sz;
190	in_offs += sz;
191	out_offs += sz;
192	}
193
194	return 0;
195	}
196
197	static int
198	cryptoloop_transfer(struct loop_device *lo, int cmd,
199	struct page *raw_page, unsigned raw_off,
200	struct page *loop_page, unsigned loop_off,
201	int size, sector_t IV)
202	{
203	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
204	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_ECB)
205	{
206	lo->transfer = cryptoloop_transfer_ecb;
207	return cryptoloop_transfer_ecb(lo, cmd, raw_page, raw_off,
208	loop_page, loop_off, size, IV);
209	}
210	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_CBC)
211	{
212	lo->transfer = cryptoloop_transfer_cbc;
213	return cryptoloop_transfer_cbc(lo, cmd, raw_page, raw_off,
214	loop_page, loop_off, size, IV);
215	}
216
217	/* This is not supposed to happen */
218
219	printk( KERN_ERR "cryptoloop: unsupported cipher mode in cryptoloop_transfer!\n");
220	return -EINVAL;
221	}
222
223	static int
224	cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg)
225	{
226	return -EINVAL;
227	}
228
229	static int
230	cryptoloop_release(struct loop_device *lo)
231	{
232	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
233	if (tfm != NULL) {
234	crypto_free_tfm(tfm);
235	lo->key_data = NULL;
236	return 0;
237	}
238	printk(KERN_ERR "cryptoloop_release(): tfm == NULL?\n");
239	return -EINVAL;
240	}
241
242	static struct loop_func_table cryptoloop_funcs = {
243	.number = LO_CRYPT_CRYPTOAPI,
244	.init = cryptoloop_init,
245	.ioctl = cryptoloop_ioctl,
246	.transfer = cryptoloop_transfer,
247	.release = cryptoloop_release,
248	.owner = THIS_MODULE
249	};
250
251	static int __init
252	init_cryptoloop(void)
253	{
254	int rc = loop_register_transfer(&cryptoloop_funcs);
255
256	if (rc)
257	printk(KERN_ERR "cryptoloop: loop_register_transfer failed\n");
258	return rc;
259	}
260
261	static void __exit
262	cleanup_cryptoloop(void)
263	{
264	if (loop_unregister_transfer(LO_CRYPT_CRYPTOAPI))
265	printk(KERN_ERR
266	"cryptoloop: loop_unregister_transfer failed\n");
267	}
268
269	module_init(init_cryptoloop);
270	module_exit(cleanup_cryptoloop);