linux-imx

/*

 * CTS: Cipher Text Stealing mode

 *

 * COPYRIGHT (c) 2008

 * The Regents of the University of Michigan

 * ALL RIGHTS RESERVED

 *

 * Permission is granted to use, copy, create derivative works

 * and redistribute this software and such derivative works

 * for any purpose, so long as the name of The University of

 * Michigan is not used in any advertising or publicity

 * pertaining to the use of distribution of this software

 * without specific, written prior authorization.  If the

 * above copyright notice or any other identification of the

 * University of Michigan is included in any copy of any

 * portion of this software, then the disclaimer below must

 * also be included.

 *

 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION

 * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY

 * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF

 * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING

 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE

 * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE

 * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR

 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING

 * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN

 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGES.

 */

​

/* Derived from various:

 *  Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>

 */

​

/*

 * This is the Cipher Text Stealing mode as described by

 * Section 8 of rfc2040 and referenced by rfc3962.

 * rfc3962 includes errata information in its Appendix A.

 */

​

#include <crypto/algapi.h>

#include <crypto/internal/skcipher.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/log2.h>

#include <linux/module.h>

#include <linux/scatterlist.h>

#include <crypto/scatterwalk.h>

#include <linux/slab.h>

#include <linux/compiler.h>

​

struct crypto_cts_ctx {

    struct crypto_skcipher *child;

};

​

struct crypto_cts_reqctx {

    struct scatterlist sg[2];

    unsigned offset;

    struct skcipher_request subreq;

};

​

static inline u8 *crypto_cts_reqctx_space(struct skcipher_request *req)

{

    struct crypto_cts_reqctx *rctx = skcipher_request_ctx(req);

    struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

    struct crypto_cts_ctx *ctx = crypto_skcipher_ctx(tfm);

    struct crypto_skcipher *child = ctx->child;

​

    return PTR_ALIGN((u8 *)(rctx + 1) + crypto_skcipher_reqsize(child),

             crypto_skcipher_alignmask(tfm) + 1);

}

​

static int crypto_cts_setkey(struct crypto_skcipher *parent, const u8 *key,

                 unsigned int keylen)

{

    struct crypto_cts_ctx *ctx = crypto_skcipher_ctx(parent);

    struct crypto_skcipher *child = ctx->child;

    int err;

​

    crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);

    crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &

                     CRYPTO_TFM_REQ_MASK);

    err = crypto_skcipher_setkey(child, key, keylen);

    crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &

                      CRYPTO_TFM_RES_MASK);

    return err;

}

​

static void cts_cbc_crypt_done(struct crypto_async_request *areq, int err)