ablk_helper.c

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/*
 * Shared async block cipher helpers
 *
 * Copyright (c) 2012 Jussi Kivilinna <[email protected]>
 *
 * Based on aesni-intel_glue.c by:
 *  Copyright (C) 2008, Intel Corp.
 *    Author: Huang Ying <[email protected]>
 *
 * This program 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 program 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 program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 */

#include <linux/kernel.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/module.h>
#include <crypto/algapi.h>
#include <crypto/cryptd.h>
#include <asm/i387.h>
#include <asm/crypto/ablk_helper.h>

int ablk_set_key(struct crypto_ablkcipher *tfm, const u8 *key,
         unsigned int key_len)
{
    struct async_helper_ctx *ctx = crypto_ablkcipher_ctx(tfm);
    struct crypto_ablkcipher *child = &ctx->cryptd_tfm->base;
    int err;

    crypto_ablkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
    crypto_ablkcipher_set_flags(child, crypto_ablkcipher_get_flags(tfm)
                    & CRYPTO_TFM_REQ_MASK);
    err = crypto_ablkcipher_setkey(child, key, key_len);
    crypto_ablkcipher_set_flags(tfm, crypto_ablkcipher_get_flags(child)
                    & CRYPTO_TFM_RES_MASK);
    return err;
}
EXPORT_SYMBOL_GPL(ablk_set_key);

int __ablk_encrypt(struct ablkcipher_request *req)
{
    struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
    struct async_helper_ctx *ctx = crypto_ablkcipher_ctx(tfm);
    struct blkcipher_desc desc;

    desc.tfm = cryptd_ablkcipher_child(ctx->cryptd_tfm);
    desc.info = req->info;
    desc.flags = 0;

    return crypto_blkcipher_crt(desc.tfm)->encrypt(
        &desc, req->dst, req->src, req->nbytes);
}
EXPORT_SYMBOL_GPL(__ablk_encrypt);

int ablk_encrypt(struct ablkcipher_request *req)
{
    struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
    struct async_helper_ctx *ctx = crypto_ablkcipher_ctx(tfm);

    if (!irq_fpu_usable()) {
        struct ablkcipher_request *cryptd_req =
            ablkcipher_request_ctx(req);

        memcpy(cryptd_req, req, sizeof(*req));
        ablkcipher_request_set_tfm(cryptd_req, &ctx->cryptd_tfm->base);

        return crypto_ablkcipher_encrypt(cryptd_req);
    } else {
        return __ablk_encrypt(req);
    }
}
EXPORT_SYMBOL_GPL(ablk_encrypt);

int ablk_decrypt(struct ablkcipher_request *req)
{
    struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
    struct async_helper_ctx *ctx = crypto_ablkcipher_ctx(tfm);

    if (!irq_fpu_usable()) {
        struct ablkcipher_request *cryptd_req =
            ablkcipher_request_ctx(req);

        memcpy(cryptd_req, req, sizeof(*req));
        ablkcipher_request_set_tfm(cryptd_req, &ctx->cryptd_tfm->base);

        return crypto_ablkcipher_decrypt(cryptd_req);
    } else {
        struct blkcipher_desc desc;

        desc.tfm = cryptd_ablkcipher_child(ctx->cryptd_tfm);
        desc.info = req->info;
        desc.flags = 0;

        return crypto_blkcipher_crt(desc.tfm)->decrypt(
            &desc, req->dst, req->src, req->nbytes);
    }
}
EXPORT_SYMBOL_GPL(ablk_decrypt);

void ablk_exit(struct crypto_tfm *tfm)
{
    struct async_helper_ctx *ctx = crypto_tfm_ctx(tfm);

    cryptd_free_ablkcipher(ctx->cryptd_tfm);
}
EXPORT_SYMBOL_GPL(ablk_exit);

int ablk_init_common(struct crypto_tfm *tfm, const char *drv_name)
{
    struct async_helper_ctx *ctx = crypto_tfm_ctx(tfm);
    struct cryptd_ablkcipher *cryptd_tfm;

    cryptd_tfm = cryptd_alloc_ablkcipher(drv_name, 0, 0);
    if (IS_ERR(cryptd_tfm))
        return PTR_ERR(cryptd_tfm);

    ctx->cryptd_tfm = cryptd_tfm;
    tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request) +
        crypto_ablkcipher_reqsize(&cryptd_tfm->base);

    return 0;
}
EXPORT_SYMBOL_GPL(ablk_init_common);

int ablk_init(struct crypto_tfm *tfm)
{
    char drv_name[CRYPTO_MAX_ALG_NAME];

    snprintf(drv_name, sizeof(drv_name), "__driver-%s",
                    crypto_tfm_alg_driver_name(tfm));

    return ablk_init_common(tfm, drv_name);
}
EXPORT_SYMBOL_GPL(ablk_init);

MODULE_LICENSE("GPL");