crypto/sha1.c

   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 <linux/init.h>
  20 #include <linux/module.h>
  21 #include <linux/mm.h>
  22 #include <linux/crypto.h>
  23 #include <linux/cryptohash.h>
  24 #include <asm/scatterlist.h>
  25 #include <asm/byteorder.h>
  26
  27 #define SHA1_DIGEST_SIZE        20
  28 #define SHA1_HMAC_BLOCK_SIZE    64
  29
  30 struct sha1_ctx {
  31         u64 count;
  32         u32 state[5];
  33         u8 buffer[64];
  34 };
  35
  36 static void sha1_init(void *ctx)
  37 {
  38         struct sha1_ctx *sctx = ctx;
  39         static const struct sha1_ctx initstate = {
  40           0,
  41           { 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0 },
  42           { 0, }
  43         };
  44
  45         *sctx = initstate;
  46 }
  47
  48 static void sha1_update(void *ctx, const u8 *data, unsigned int len)
  49 {
  50         struct sha1_ctx *sctx = ctx;
  51         unsigned int i, j;
  52         u32 temp[SHA_WORKSPACE_WORDS];
  53
  54         j = (sctx->count >> 3) & 0x3f;
  55         sctx->count += len << 3;
  56
  57         if ((j + len) > 63) {
  58                 memcpy(&sctx->buffer[j], data, (i = 64-j));
  59                 sha_transform(sctx->state, sctx->buffer, temp);
  60                 for ( ; i + 63 < len; i += 64) {
  61                         sha_transform(sctx->state, &data[i], temp);
  62                 }
  63                 j = 0;
  64         }
  65         else i = 0;
  66         memset(temp, 0, sizeof(temp));
  67         memcpy(&sctx->buffer[j], &data[i], len - i);
  68 }
  69
  70
  71 /* Add padding and return the message digest. */
  72 static void sha1_final(void* ctx, u8 *out)
  73 {
  74         struct sha1_ctx *sctx = ctx;
  75         u32 i, j, index, padlen;
  76         u64 t;
  77         u8 bits[8] = { 0, };
  78         static const u8 padding[64] = { 0x80, };
  79
  80         t = sctx->count;
  81         bits[7] = 0xff & t; t>>=8;
  82         bits[6] = 0xff & t; t>>=8;
  83         bits[5] = 0xff & t; t>>=8;
  84         bits[4] = 0xff & t; t>>=8;
  85         bits[3] = 0xff & t; t>>=8;
  86         bits[2] = 0xff & t; t>>=8;
  87         bits[1] = 0xff & t; t>>=8;
  88         bits[0] = 0xff & t;
  89
  90         /* Pad out to 56 mod 64 */
  91         index = (sctx->count >> 3) & 0x3f;
  92         padlen = (index < 56) ? (56 - index) : ((64+56) - index);
  93         sha1_update(sctx, padding, padlen);
  94
  95         /* Append length */
  96         sha1_update(sctx, bits, sizeof bits);
  97
  98         /* Store state in digest */
  99         for (i = j = 0; i < 5; i++, j += 4) {
 100                 u32 t2 = sctx->state[i];
 101                 out[j+3] = t2 & 0xff; t2>>=8;
 102                 out[j+2] = t2 & 0xff; t2>>=8;
 103                 out[j+1] = t2 & 0xff; t2>>=8;
 104                 out[j  ] = t2 & 0xff;
 105         }
 106
 107         /* Wipe context */
 108         memset(sctx, 0, sizeof *sctx);
 109 }
 110
 111 static struct crypto_alg alg = {
 112         .cra_name       =       "sha1",
 113         .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 114         .cra_blocksize  =       SHA1_HMAC_BLOCK_SIZE,
 115         .cra_ctxsize    =       sizeof(struct sha1_ctx),
 116         .cra_module     =       THIS_MODULE,
 117         .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
 118         .cra_u          =       { .digest = {
 119         .dia_digestsize =       SHA1_DIGEST_SIZE,
 120         .dia_init       =       sha1_init,
 121         .dia_update     =       sha1_update,
 122         .dia_final      =       sha1_final } }
 123 };
 124
 125 static int __init init(void)
 126 {
 127         return crypto_register_alg(&alg);
 128 }
 129
 130 static void __exit fini(void)
 131 {
 132         crypto_unregister_alg(&alg);
 133 }
 134
 135 module_init(init);
 136 module_exit(fini);
 137
 138 MODULE_LICENSE("GPL");
 139 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");