linux-imx

/*

 * Key Wrapping: RFC3394 / NIST SP800-38F

 *

 * Copyright (C) 2015, Stephan Mueller <smueller@chronox.de>

 *

 * 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, and the entire permission notice in its entirety,

 *    including the disclaimer of warranties.

 * 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.

 *

 * ALTERNATIVELY, this product may be distributed under the terms of

 * the GNU General Public License, in which case the provisions of the GPL2

 * are required INSTEAD OF the above restrictions.  (This clause is

 * necessary due to a potential bad interaction between the GPL and

 * the restrictions contained in a BSD-style copyright.)

 *

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF

 * WHICH ARE HEREBY 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 NOT ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 */

​

/*

 * Note for using key wrapping:

 *

 *  * The result of the encryption operation is the ciphertext starting

 *    with the 2nd semiblock. The first semiblock is provided as the IV.

 *    The IV used to start the encryption operation is the default IV.

 *

 *  * The input for the decryption is the first semiblock handed in as an

 *    IV. The ciphertext is the data starting with the 2nd semiblock. The

 *    return code of the decryption operation will be EBADMSG in case an

 *    integrity error occurs.

 *

 * To obtain the full result of an encryption as expected by SP800-38F, the

 * caller must allocate a buffer of plaintext + 8 bytes:

 *

 *  unsigned int datalen = ptlen + crypto_skcipher_ivsize(tfm);

 *  u8 data[datalen];

 *  u8 *iv = data;

 *  u8 *pt = data + crypto_skcipher_ivsize(tfm);

 *      <ensure that pt contains the plaintext of size ptlen>

 *  sg_init_one(&sg, pt, ptlen);

 *  skcipher_request_set_crypt(req, &sg, &sg, ptlen, iv);

 *

 *  ==> After encryption, data now contains full KW result as per SP800-38F.

 *

 * In case of decryption, ciphertext now already has the expected length

 * and must be segmented appropriately:

 *

 *  unsigned int datalen = CTLEN;

 *  u8 data[datalen];

 *      <ensure that data contains full ciphertext>

 *  u8 *iv = data;

 *  u8 *ct = data + crypto_skcipher_ivsize(tfm);

 *  unsigned int ctlen = datalen - crypto_skcipher_ivsize(tfm);

 *  sg_init_one(&sg, ct, ctlen);

 *  skcipher_request_set_crypt(req, &sg, &sg, ctlen, iv);

 *

 *  ==> After decryption (which hopefully does not return EBADMSG), the ct

 *  pointer now points to the plaintext of size ctlen.

 *

 * Note 2: KWP is not implemented as this would defy in-place operation.

 *     If somebody wants to wrap non-aligned data, he should simply pad

 *     the input with zeros to fill it up to the 8 byte boundary.

 */

​

#include <linux/module.h>

#include <linux/crypto.h>

#include <linux/scatterlist.h>

#include <crypto/scatterwalk.h>

#include <crypto/internal/skcipher.h>

​

struct crypto_kw_block {

#define SEMIBSIZE 8

    __be64 A;