linux-imx

/*

   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 int

cryptoloop_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;

​