sha1_glue.c

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/*
 * Cryptographic API.
 * Glue code for the SHA1 Secure Hash Algorithm assembler implementation
 *
 * This file is based on sha1_generic.c and sha1_ssse3_glue.c
 *
 * Copyright (c) Alan Smithee.
 * Copyright (c) Andrew McDonald <[email protected]>
 * Copyright (c) Jean-Francois Dive <[email protected]>
 * Copyright (c) Mathias Krause <[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.
 *
 */

#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/cryptohash.h>
#include <linux/types.h>
#include <crypto/sha.h>
#include <asm/byteorder.h>

struct SHA1_CTX {
    uint32_t h0,h1,h2,h3,h4;
    u64 count;
    u8 data[SHA1_BLOCK_SIZE];
};

asmlinkage void sha1_block_data_order(struct SHA1_CTX *digest,
        const unsigned char *data, unsigned int rounds);


static int sha1_init(struct shash_desc *desc)
{
    struct SHA1_CTX *sctx = shash_desc_ctx(desc);
    memset(sctx, 0, sizeof(*sctx));
    sctx->h0 = SHA1_H0;
    sctx->h1 = SHA1_H1;
    sctx->h2 = SHA1_H2;
    sctx->h3 = SHA1_H3;
    sctx->h4 = SHA1_H4;
    return 0;
}


static int __sha1_update(struct SHA1_CTX *sctx, const u8 *data,
                   unsigned int len, unsigned int partial)
{
    unsigned int done = 0;

    sctx->count += len;

    if (partial) {
        done = SHA1_BLOCK_SIZE - partial;
        memcpy(sctx->data + partial, data, done);
        sha1_block_data_order(sctx, sctx->data, 1);
    }

    if (len - done >= SHA1_BLOCK_SIZE) {
        const unsigned int rounds = (len - done) / SHA1_BLOCK_SIZE;
        sha1_block_data_order(sctx, data + done, rounds);
        done += rounds * SHA1_BLOCK_SIZE;
    }

    memcpy(sctx->data, data + done, len - done);
    return 0;
}


static int sha1_update(struct shash_desc *desc, const u8 *data,
                 unsigned int len)
{
    struct SHA1_CTX *sctx = shash_desc_ctx(desc);
    unsigned int partial = sctx->count % SHA1_BLOCK_SIZE;
    int res;

    /* Handle the fast case right here */
    if (partial + len < SHA1_BLOCK_SIZE) {
        sctx->count += len;
        memcpy(sctx->data + partial, data, len);
        return 0;
    }
    res = __sha1_update(sctx, data, len, partial);
    return res;
}


/* Add padding and return the message digest. */
static int sha1_final(struct shash_desc *desc, u8 *out)
{
    struct SHA1_CTX *sctx = shash_desc_ctx(desc);
    unsigned int i, index, padlen;
    __be32 *dst = (__be32 *)out;
    __be64 bits;
    static const u8 padding[SHA1_BLOCK_SIZE] = { 0x80, };

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

    /* Pad out to 56 mod 64 and append length */
    index = sctx->count % SHA1_BLOCK_SIZE;
    padlen = (index < 56) ? (56 - index) : ((SHA1_BLOCK_SIZE+56) - index);
    /* We need to fill a whole block for __sha1_update() */
    if (padlen <= 56) {
        sctx->count += padlen;
        memcpy(sctx->data + index, padding, padlen);
    } else {
        __sha1_update(sctx, padding, padlen, index);
    }
    __sha1_update(sctx, (const u8 *)&bits, sizeof(bits), 56);

    /* Store state in digest */
    for (i = 0; i < 5; i++)
        dst[i] = cpu_to_be32(((u32 *)sctx)[i]);

    /* Wipe context */
    memset(sctx, 0, sizeof(*sctx));
    return 0;
}


static int sha1_export(struct shash_desc *desc, void *out)
{
    struct SHA1_CTX *sctx = shash_desc_ctx(desc);
    memcpy(out, sctx, sizeof(*sctx));
    return 0;
}


static int sha1_import(struct shash_desc *desc, const void *in)
{
    struct SHA1_CTX *sctx = shash_desc_ctx(desc);
    memcpy(sctx, in, sizeof(*sctx));
    return 0;
}


static struct shash_alg alg = {
    .digestsize =   SHA1_DIGEST_SIZE,
    .init       =   sha1_init,
    .update     =   sha1_update,
    .final      =   sha1_final,
    .export     =   sha1_export,
    .import     =   sha1_import,
    .descsize   =   sizeof(struct SHA1_CTX),
    .statesize  =   sizeof(struct SHA1_CTX),
    .base       =   {
        .cra_name   =   "sha1",
        .cra_driver_name=   "sha1-asm",
        .cra_priority   =   150,
        .cra_flags  =   CRYPTO_ALG_TYPE_SHASH,
        .cra_blocksize  =   SHA1_BLOCK_SIZE,
        .cra_module =   THIS_MODULE,
    }
};


static int __init sha1_mod_init(void)
{
    return crypto_register_shash(&alg);
}


static void __exit sha1_mod_fini(void)
{
    crypto_unregister_shash(&alg);
}


module_init(sha1_mod_init);
module_exit(sha1_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm (ARM)");
MODULE_ALIAS("sha1");
MODULE_AUTHOR("David McCullough <[email protected]>");