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 <linux/types.h>
  25 #include <asm/scatterlist.h>
  26 #include <asm/byteorder.h>
  27
  28 #define SHA1_DIGEST_SIZE        20
  29 #define SHA1_HMAC_BLOCK_SIZE    64
  30
  31 struct sha1_ctx {
  32         u64 count;
  33         u32 state[5];
  34         u8 buffer[64];
  35 };
  36
  37 static void sha1_init(void *ctx)
  38 {
  39         struct sha1_ctx *sctx = ctx;
  40         static const struct sha1_ctx initstate = {
  41           0,
  42           { 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0 },
  43           { 0, }
  44         };
  45
  46         *sctx = initstate;
  47 }
  48
  49 static void sha1_update(void *ctx, const u8 *data, unsigned int len)
  50 {
  51         struct sha1_ctx *sctx = ctx;
  52         unsigned int partial, done;
  53         const u8 *src;
  54
  55         partial = sctx->count & 0x3f;
  56         sctx->count += len;
  57         done = 0;
  58         src = data;
  59
  60         if ((partial + len) > 63) {
  61                 u32 temp[SHA_WORKSPACE_WORDS];
  62
  63                 if (partial) {
  64                         done = -partial;
  65                         memcpy(sctx->buffer + partial, data, done + 64);
  66                         src = sctx->buffer;
  67                 }
  68
  69                 do {
  70                         sha_transform(sctx->state, src, temp);
  71                         done += 64;
  72                         src = data + done;
  73                 } while (done + 63 < len);
  74
  75                 memset(temp, 0, sizeof(temp));
  76                 partial = 0;
  77         }
  78         memcpy(sctx->buffer + partial, src, len - done);
  79 }
  80
  81
  82 /* Add padding and return the message digest. */
  83 static void sha1_final(void* ctx, u8 *out)
  84 {
  85         struct sha1_ctx *sctx = ctx;
  86         __be32 *dst = (__be32 *)out;
  87         u32 i, index, padlen;
  88         __be64 bits;
  89         static const u8 padding[64] = { 0x80, };
  90
  91         bits = cpu_to_be64(sctx->count << 3);
  92
  93         /* Pad out to 56 mod 64 */
  94         index = sctx->count & 0x3f;
  95         padlen = (index < 56) ? (56 - index) : ((64+56) - index);
  96         sha1_update(sctx, padding, padlen);
  97
  98         /* Append length */
  99         sha1_update(sctx, (const u8 *)&bits, sizeof(bits));
 100
 101         /* Store state in digest */
 102         for (i = 0; i < 5; i++)
 103                 dst[i] = cpu_to_be32(sctx->state[i]);
 104
 105         /* Wipe context */
 106         memset(sctx, 0, sizeof *sctx);
 107 }
 108
 109 static struct crypto_alg alg = {
 110         .cra_name       =       "sha1",
 111         .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 112         .cra_blocksize  =       SHA1_HMAC_BLOCK_SIZE,
 113         .cra_ctxsize    =       sizeof(struct sha1_ctx),
 114         .cra_module     =       THIS_MODULE,
 115         .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
 116         .cra_u          =       { .digest = {
 117         .dia_digestsize =       SHA1_DIGEST_SIZE,
 118         .dia_init       =       sha1_init,
 119         .dia_update     =       sha1_update,
 120         .dia_final      =       sha1_final } }
 121 };
 122
 123 static int __init init(void)
 124 {
 125         return crypto_register_alg(&alg);
 126 }
 127
 128 static void __exit fini(void)
 129 {
 130         crypto_unregister_alg(&alg);
 131 }
 132
 133 module_init(init);
 134 module_exit(fini);
 135
 136 MODULE_LICENSE("GPL");
 137 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");