[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);
	else if (strcmp(mode, "ecb") == 0)
		tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_ECB);
	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)
	60	tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_CBC);
	61	else if (strcmp(mode, "ecb") == 0)
	62	tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_ECB);
	63	if (tfm == NULL)
	64	return -EINVAL;
65
66	err = tfm->crt_u.cipher.cit_setkey(tfm, info->lo_encrypt_key,
67	info->lo_encrypt_key_size);
68
69	if (err != 0)
70	goto out_free_tfm;
71
72	lo->key_data = tfm;
73	return 0;
74
75	out_free_tfm:
76	crypto_free_tfm(tfm);
77
78	out:
79	return err;
80	}
81
82
83	typedef int (encdec_ecb_t)(struct crypto_tfm tfm,
84	struct scatterlist *sg_out,
85	struct scatterlist *sg_in,
86	unsigned int nsg);
87
88
89	static int
90	cryptoloop_transfer_ecb(struct loop_device *lo, int cmd,
91	struct page *raw_page, unsigned raw_off,
92	struct page *loop_page, unsigned loop_off,
93	int size, sector_t IV)
94	{
95	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
96	struct scatterlist sg_out = { NULL, };
97	struct scatterlist sg_in = { NULL, };
98
99	encdec_ecb_t encdecfunc;
100	struct page in_page, out_page;
101	unsigned in_offs, out_offs;
102
103	if (cmd == READ) {
104	in_page = raw_page;
105	in_offs = raw_off;
106	out_page = loop_page;
107	out_offs = loop_off;
108	encdecfunc = tfm->crt_u.cipher.cit_decrypt;
109	} else {
110	in_page = loop_page;
111	in_offs = loop_off;
112	out_page = raw_page;
113	out_offs = raw_off;
114	encdecfunc = tfm->crt_u.cipher.cit_encrypt;
115	}
116
117	while (size > 0) {
118	const int sz = min(size, LOOP_IV_SECTOR_SIZE);
119
120	sg_in.page = in_page;
121	sg_in.offset = in_offs;
122	sg_in.length = sz;
123
124	sg_out.page = out_page;
125	sg_out.offset = out_offs;
126	sg_out.length = sz;
127
128	encdecfunc(tfm, &sg_out, &sg_in, sz);
129
130	size -= sz;
131	in_offs += sz;
132	out_offs += sz;
133	}
134
135	return 0;
136	}
137
138	typedef int (encdec_cbc_t)(struct crypto_tfm tfm,
139	struct scatterlist *sg_out,
140	struct scatterlist *sg_in,
141	unsigned int nsg, u8 *iv);
142
143	static int
144	cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
145	struct page *raw_page, unsigned raw_off,
146	struct page *loop_page, unsigned loop_off,
147	int size, sector_t IV)
148	{
149	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
150	struct scatterlist sg_out = { NULL, };
151	struct scatterlist sg_in = { NULL, };
152
153	encdec_cbc_t encdecfunc;
154	struct page in_page, out_page;
155	unsigned in_offs, out_offs;
156
157	if (cmd == READ) {
158	in_page = raw_page;
159	in_offs = raw_off;
160	out_page = loop_page;
161	out_offs = loop_off;
162	encdecfunc = tfm->crt_u.cipher.cit_decrypt_iv;
163	} else {
164	in_page = loop_page;
165	in_offs = loop_off;
166	out_page = raw_page;
167	out_offs = raw_off;
168	encdecfunc = tfm->crt_u.cipher.cit_encrypt_iv;
169	}
170
171	while (size > 0) {
172	const int sz = min(size, LOOP_IV_SECTOR_SIZE);
173	u32 iv[4] = { 0, };
174	iv[0] = cpu_to_le32(IV & 0xffffffff);
175
176	sg_in.page = in_page;
177	sg_in.offset = in_offs;
178	sg_in.length = sz;
179
180	sg_out.page = out_page;
181	sg_out.offset = out_offs;
182	sg_out.length = sz;
183
184	encdecfunc(tfm, &sg_out, &sg_in, sz, (u8 *)iv);
185
186	IV++;
187	size -= sz;
188	in_offs += sz;
189	out_offs += sz;
190	}
191
192	return 0;
193	}
194
195	static int
196	cryptoloop_transfer(struct loop_device *lo, int cmd,
197	struct page *raw_page, unsigned raw_off,
198	struct page *loop_page, unsigned loop_off,
199	int size, sector_t IV)
200	{
201	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
202	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_ECB)
203	{
204	lo->transfer = cryptoloop_transfer_ecb;
205	return cryptoloop_transfer_ecb(lo, cmd, raw_page, raw_off,
206	loop_page, loop_off, size, IV);
207	}
208	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_CBC)
209	{
210	lo->transfer = cryptoloop_transfer_cbc;
211	return cryptoloop_transfer_cbc(lo, cmd, raw_page, raw_off,
212	loop_page, loop_off, size, IV);
213	}
214
215	/* This is not supposed to happen */
216
217	printk( KERN_ERR "cryptoloop: unsupported cipher mode in cryptoloop_transfer!\n");
218	return -EINVAL;
219	}
220
221	static int
222	cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg)
223	{
224	return -EINVAL;
225	}
226
227	static int
228	cryptoloop_release(struct loop_device *lo)
229	{
230	struct crypto_tfm tfm = (struct crypto_tfm ) lo->key_data;
231	if (tfm != NULL) {
232	crypto_free_tfm(tfm);
233	lo->key_data = NULL;
234	return 0;
235	}
236	printk(KERN_ERR "cryptoloop_release(): tfm == NULL?\n");
237	return -EINVAL;
238	}
239
240	static struct loop_func_table cryptoloop_funcs = {
241	.number = LO_CRYPT_CRYPTOAPI,
242	.init = cryptoloop_init,
243	.ioctl = cryptoloop_ioctl,
244	.transfer = cryptoloop_transfer,
245	.release = cryptoloop_release,
246	.owner = THIS_MODULE
247	};
248
249	static int __init
250	init_cryptoloop(void)
251	{
252	int rc = loop_register_transfer(&cryptoloop_funcs);
253
254	if (rc)
255	printk(KERN_ERR "cryptoloop: loop_register_transfer failed\n");
256	return rc;
257	}
258
259	static void __exit
260	cleanup_cryptoloop(void)
261	{
262	if (loop_unregister_transfer(LO_CRYPT_CRYPTOAPI))
263	printk(KERN_ERR
264	"cryptoloop: loop_unregister_transfer failed\n");
265	}
266
267	module_init(init_cryptoloop);
268	module_exit(cleanup_cryptoloop);