LXR linux/crypto/sha1

   1/*
   2 * Cryptographic API.
   3 *
   4 * SHA1 Secure Hash Algorithm.
   5 *
   6 * Derived from cryptoapi implementation, adapted for in-place
   7 * scatterlist interface.
   8 *
   9 * Copyright (c) Alan Smithee.
  10 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
  11 * Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
  12 *
  13 * This program is free software; you can redistribute it and/or modify it
  14 * under the terms of the GNU General Public License as published by the Free
  15 * Software Foundation; either version 2 of the License, or (at your option)
  16 * any later version.
  17 *
  18 */
  19#include <crypto/internal/hash.h>
  20#include <linux/init.h>
  21#include <linux/module.h>
  22#include <linux/mm.h>
  23#include <linux/cryptohash.h>
  24#include <linux/types.h>
  25#include <crypto/sha.h>
  26#include <asm/byteorder.h>
  27
  28static int sha1_init(struct shash_desc *desc)
  29{
  30        struct sha1_state *sctx = shash_desc_ctx(desc);
  31
  32        *sctx = (struct sha1_state){
  33                .state = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
  34        };
  35
  36        return 0;
  37}
  38
  39int crypto_sha1_update(struct shash_desc *desc, const u8 *data,
  40                        unsigned int len)
  41{
  42        struct sha1_state *sctx = shash_desc_ctx(desc);
  43        unsigned int partial, done;
  44        const u8 *src;
  45
  46        partial = sctx->count % SHA1_BLOCK_SIZE;
  47        sctx->count += len;
  48        done = 0;
  49        src = data;
  50
  51        if ((partial + len) >= SHA1_BLOCK_SIZE) {
  52                u32 temp[SHA_WORKSPACE_WORDS];
  53
  54                if (partial) {
  55                        done = -partial;
  56                        memcpy(sctx->buffer + partial, data,
  57                               done + SHA1_BLOCK_SIZE);
  58                        src = sctx->buffer;
  59                }
  60
  61                do {
  62                        sha_transform(sctx->state, src, temp);
  63                        done += SHA1_BLOCK_SIZE;
  64                        src = data + done;
  65                } while (done + SHA1_BLOCK_SIZE <= len);
  66
  67                memset(temp, 0, sizeof(temp));
  68                partial = 0;
  69        }
  70        memcpy(sctx->buffer + partial, src, len - done);
  71
  72        return 0;
  73}
  74EXPORT_SYMBOL(crypto_sha1_update);
  75
  76
  77/* Add padding and return the message digest. */
  78static int sha1_final(struct shash_desc *desc, u8 *out)
  79{
  80        struct sha1_state *sctx = shash_desc_ctx(desc);
  81        __be32 *dst = (__be32 *)out;
  82        u32 i, index, padlen;
  83        __be64 bits;
  84        static const u8 padding[64] = { 0x80, };
  85
  86        bits = cpu_to_be64(sctx->count << 3);
  87
  88        /* Pad out to 56 mod 64 */
  89        index = sctx->count & 0x3f;
  90        padlen = (index < 56) ? (56 - index) : ((64+56) - index);
  91        crypto_sha1_update(desc, padding, padlen);
  92
  93        /* Append length */
  94        crypto_sha1_update(desc, (const u8 *)&bits, sizeof(bits));
  95
  96        /* Store state in digest */
  97        for (i = 0; i < 5; i++)
  98                dst[i] = cpu_to_be32(sctx->state[i]);
  99
 100        /* Wipe context */
 101        memset(sctx, 0, sizeof *sctx);
 102
 103        return 0;
 104}
 105
 106static int sha1_export(struct shash_desc *desc, void *out)
 107{
 108        struct sha1_state *sctx = shash_desc_ctx(desc);
 109
 110        memcpy(out, sctx, sizeof(*sctx));
 111        return 0;
 112}
 113
 114static int sha1_import(struct shash_desc *desc, const void *in)
 115{
 116        struct sha1_state *sctx = shash_desc_ctx(desc);
 117
 118        memcpy(sctx, in, sizeof(*sctx));
 119        return 0;
 120}
 121
 122static struct shash_alg alg = {
 123        .digestsize     =       SHA1_DIGEST_SIZE,
 124        .init           =       sha1_init,
 125        .update         =       crypto_sha1_update,
 126        .final          =       sha1_final,
 127        .export         =       sha1_export,
 128        .import         =       sha1_import,
 129        .descsize       =       sizeof(struct sha1_state),
 130        .statesize      =       sizeof(struct sha1_state),
 131        .base           =       {
 132                .cra_name       =       "sha1",
 133                .cra_driver_name=       "sha1-generic",
 134                .cra_flags      =       CRYPTO_ALG_TYPE_SHASH,
 135                .cra_blocksize  =       SHA1_BLOCK_SIZE,
 136                .cra_module     =       THIS_MODULE,
 137        }
 138};
 139
 140static int __init sha1_generic_mod_init(void)
 141{
 142        return crypto_register_shash(&alg);
 143}
 144
 145static void __exit sha1_generic_mod_fini(void)
 146{
 147        crypto_unregister_shash(&alg);
 148}
 149
 150module_init(sha1_generic_mod_init);
 151module_exit(sha1_generic_mod_fini);
 152
 153MODULE_LICENSE("GPL");
 154MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
 155
 156MODULE_ALIAS("sha1");
 157