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/*

 * Cryptographic API.

 *

 * SHA1 Secure Hash Algorithm.

 *

 * Derived from cryptoapi implementation, adapted for in-place

 * scatterlist interface.

 *

 * Copyright (c) Alan Smithee.

 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>

 * Copyright (c) Jean-Francois Dive <jef@linuxbe.org>

 *

 * 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.

 *

 */

#include <linux/init.h>

#include <linux/module.h>

#include <linux/mm.h>

#include <linux/crypto.h>

#include <linux/cryptohash.h>

#include <linux/types.h>

#include <crypto/sha.h>

#include <asm/byteorder.h>

struct sha1_ctx {

        u64 count;

        u32 state[5];

        u8 buffer[64];

};

static void sha1_init(struct crypto_tfm *tfm)

{

        struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);

        static const struct sha1_ctx initstate = {

          0,

          { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },

          { 0, }

        };

        *sctx = initstate;

}

static void sha1_update(struct crypto_tfm *tfm, const u8 *data,

                        unsigned int len)

{

        struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);

        unsigned int partial, done;

        const u8 *src;

        partial = sctx->count & 0x3f;

        sctx->count += len;

        done = 0;

        src = data;

        if ((partial + len) > 63) {

                u32 temp[SHA_WORKSPACE_WORDS];

                if (partial) {

                        done = -partial;

                        memcpy(sctx->buffer + partial, data, done + 64);

                        src = sctx->buffer;

                }

                do {

                        sha_transform(sctx->state, src, temp);

                        done += 64;

                        src = data + done;

                } while (done + 63 < len);

                memset(temp, 0, sizeof(temp));

                partial = 0;

        }

        memcpy(sctx->buffer + partial, src, len - done);

}

/* Add padding and return the message digest. */

static void sha1_final(struct crypto_tfm *tfm, u8 *out)

{

        struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);

        __be32 *dst = (__be32 *)out;

        u32 i, index, padlen;

        __be64 bits;

        static const u8 padding[64] = { 0x80, };

        bits = cpu_to_be64(sctx->count << 3);

        /* Pad out to 56 mod 64 */

        index = sctx->count & 0x3f;

        padlen = (index < 56) ? (56 - index) : ((64+56) - index);

        sha1_update(tfm, padding, padlen);

        /* Append length */

        sha1_update(tfm, (const u8 *)&bits, sizeof(bits));

        /* Store state in digest */

        for (i = 0; i < 5; i++)

                dst[i] = cpu_to_be32(sctx->state[i]);

        /* Wipe context */

        memset(sctx, 0, sizeof *sctx);

}

static struct crypto_alg alg = {

        .cra_name       =       "sha1",

        .cra_driver_name=       "sha1-generic",

        .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,

        .cra_blocksize  =       SHA1_BLOCK_SIZE,

        .cra_ctxsize    =       sizeof(struct sha1_ctx),

        .cra_module     =       THIS_MODULE,

        .cra_alignmask  =       3,

        .cra_list       =       LIST_HEAD_INIT(alg.cra_list),

        .cra_u          =       { .digest = {

        .dia_digestsize =       SHA1_DIGEST_SIZE,

        .dia_init       =       sha1_init,

        .dia_update     =       sha1_update,

        .dia_final      =       sha1_final } }

};

static int __init init(void)

{

        return crypto_register_alg(&alg);

}

static void __exit fini(void)

{

        crypto_unregister_alg(&alg);

}

module_init(init);

module_exit(fini);

MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");

MODULE_ALIAS("sha1");