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
  39static int 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 & 0x3f;
  47        sctx->count += len;
  48        done = 0;
  49        src = data;
  50
  51        if ((partial + len) > 63) {
  52                u32 temp[SHA_WORKSPACE_WORDS];
  53
  54                if (partial) {
  55                        done = -partial;
  56                        memcpy(sctx->buffer + partial, data, done + 64);
  57                        src = sctx->buffer;
  58                }
  59
  60                do {
  61                        sha_transform(sctx->state, src, temp);
  62                        done += 64;
  63                        src = data + done;
  64                } while (done + 63 < len);
  65
  66                memset(temp, 0, sizeof(temp));
  67                partial = 0;
  68        }
  69        memcpy(sctx->buffer + partial, src, len - done);
  70
  71        return 0;
  72}
  73
  74
  75/* Add padding and return the message digest. */
  76static int sha1_final(struct shash_desc *desc, u8 *out)
  77{
  78        struct sha1_state *sctx = shash_desc_ctx(desc);
  79        __be32 *dst = (__be32 *)out;
  80        u32 i, index, padlen;
  81        __be64 bits;
  82        static const u8 padding[64] = { 0x80, };
  83
  84        bits = cpu_to_be64(sctx->count << 3);
  85
  86        /* Pad out to 56 mod 64 */
  87        index = sctx->count & 0x3f;
  88        padlen = (index < 56) ? (56 - index) : ((64+56) - index);
  89        sha1_update(desc, padding, padlen);
  90
  91        /* Append length */
  92        sha1_update(desc, (const u8 *)&bits, sizeof(bits));
  93
  94        /* Store state in digest */
  95        for (i = 0; i < 5; i++)
  96                dst[i] = cpu_to_be32(sctx->state[i]);
  97
  98        /* Wipe context */
  99        memset(sctx, 0, sizeof *sctx);
 100
 101        return 0;
 102}
 103
 104static int sha1_export(struct shash_desc *desc, void *out)
 105{
 106        struct sha1_state *sctx = shash_desc_ctx(desc);
 107
 108        memcpy(out, sctx, sizeof(*sctx));
 109        return 0;
 110}
 111
 112static int sha1_import(struct shash_desc *desc, const void *in)
 113{
 114        struct sha1_state *sctx = shash_desc_ctx(desc);
 115
 116        memcpy(sctx, in, sizeof(*sctx));
 117        return 0;
 118}
 119
 120static struct shash_alg alg = {
 121        .digestsize     =       SHA1_DIGEST_SIZE,
 122        .init           =       sha1_init,
 123        .update         =       sha1_update,
 124        .final          =       sha1_final,
 125        .export         =       sha1_export,
 126        .import         =       sha1_import,
 127        .descsize       =       sizeof(struct sha1_state),
 128        .statesize      =       sizeof(struct sha1_state),
 129        .base           =       {
 130                .cra_name       =       "sha1",
 131                .cra_driver_name=       "sha1-generic",
 132                .cra_flags      =       CRYPTO_ALG_TYPE_SHASH,
 133                .cra_blocksize  =       SHA1_BLOCK_SIZE,
 134                .cra_module     =       THIS_MODULE,
 135        }
 136};
 137
 138static int __init sha1_generic_mod_init(void)
 139{
 140        return crypto_register_shash(&alg);
 141}
 142
 143static void __exit sha1_generic_mod_fini(void)
 144{
 145        crypto_unregister_shash(&alg);
 146}
 147
 148module_init(sha1_generic_mod_init);
 149module_exit(sha1_generic_mod_fini);
 150
 151MODULE_LICENSE("GPL");
 152MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
 153
 154MODULE_ALIAS("sha1");
 155