/*   Linux loop encryption enabling module    Copyright (C)  2002 Herbert Valerio Riedel <hvr@gnu.org>   Copyright (C)  2003 Fruhwirth Clemens <clemens@endorphin.org>    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 <crypto/skcipher.h>#include <linux/init.h>#include <linux/string.h>#include <linux/blkdev.h>#include <linux/scatterlist.h>#include <linux/uaccess.h>#include "loop.h" MODULE_LICENSE("GPL");MODULE_DESCRIPTION("loop blockdevice transferfunction adaptor / CryptoAPI");MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>"); #define LOOP_IV_SECTOR_BITS 9#define LOOP_IV_SECTOR_SIZE (1 << LOOP_IV_SECTOR_BITS) static intcryptoloop_init(struct loop_device *lo, const struct loop_info64 *info){	int err = -EINVAL;	int cipher_len;	int mode_len;	char cms[LO_NAME_SIZE];			/* cipher-mode string */	char *mode;	char *cmsp = cms;			/* c-m string pointer */	struct crypto_sync_skcipher *tfm; 	/* 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_len = strcspn(cmsp, "-"); 	mode = cmsp + cipher_len;	mode_len = 0;	if (*mode) {		mode++;		mode_len = strcspn(mode, "-");	} 	if (!mode_len) {		mode = "cbc";		mode_len = 3;	} 	if (cipher_len + mode_len + 3 > LO_NAME_SIZE)		return -EINVAL; 	memmove(cms, mode, mode_len);	cmsp = cms + mode_len;	*cmsp++ = '(';	memcpy(cmsp, info->lo_crypt_name, cipher_len);	cmsp += cipher_len;	*cmsp++ = ')';	*cmsp = 0; 	tfm = crypto_alloc_sync_skcipher(cms, 0, 0);	if (IS_ERR(tfm))		return PTR_ERR(tfm); 	err = crypto_sync_skcipher_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_sync_skcipher(tfm);  out:	return err;}  typedef int (*encdec_cbc_t)(struct skcipher_request *req); static intcryptoloop_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_sync_skcipher *tfm = lo->key_data;	SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);	struct scatterlist sg_out;	struct scatterlist sg_in; 	encdec_cbc_t encdecfunc;	struct page *in_page, *out_page;	unsigned in_offs, out_offs;	int err; 	skcipher_request_set_sync_tfm(req, tfm);	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,				      NULL, NULL); 	sg_init_table(&sg_out, 1);	sg_init_table(&sg_in, 1); 	if (cmd == READ) {		in_page = raw_page;		in_offs = raw_off;		out_page = loop_page;		out_offs = loop_off;		encdecfunc = crypto_skcipher_decrypt;	} else {		in_page = loop_page;		in_offs = loop_off;		out_page = raw_page;		out_offs = raw_off;		encdecfunc = crypto_skcipher_encrypt;	} 	while (size > 0) {		const int sz = min(size, LOOP_IV_SECTOR_SIZE);		u32 iv[4] = { 0, };		iv[0] = cpu_to_le32(IV & 0xffffffff); 		sg_set_page(&sg_in, in_page, sz, in_offs);		sg_set_page(&sg_out, out_page, sz, out_offs); 		skcipher_request_set_crypt(req, &sg_in, &sg_out, sz, iv);		err = encdecfunc(req);		if (err)			goto out; 		IV++;		size -= sz;		in_offs += sz;		out_offs += sz;	} 	err = 0; out:	skcipher_request_zero(req);	return err;} static intcryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg){	return -EINVAL;} static intcryptoloop_release(struct loop_device *lo){	struct crypto_sync_skcipher *tfm = lo->key_data;	if (tfm != NULL) {		crypto_free_sync_skcipher(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 __initinit_cryptoloop(void){	int rc = loop_register_transfer(&cryptoloop_funcs); 	if (rc)		printk(KERN_ERR "cryptoloop: loop_register_transfer failed\n");	return rc;} static void __exitcleanup_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);