crypto/sha1_generic.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 <crypto/sha.h>
  26 #include <asm/scatterlist.h>
  27 #include <asm/byteorder.h>
  28
  29 struct sha1_ctx {
  30         u64 count;
  31         u32 state[5];
  32         u8 buffer[64];
  33 };
  34
  35 static void sha1_init(struct crypto_tfm *tfm)
  36 {
  37         struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
  38         static const struct sha1_ctx initstate = {
  39           0,
  40           { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
  41           { 0, }
  42         };
  43
  44         *sctx = initstate;
  45 }
  46
  47 static void sha1_update(struct crypto_tfm *tfm, const u8 *data,
  48                         unsigned int len)
  49 {
  50         struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
  51         unsigned int partial, done;
  52         const u8 *src;
  53
  54         partial = sctx->count & 0x3f;
  55         sctx->count += len;
  56         done = 0;
  57         src = data;
  58
  59         if ((partial + len) > 63) {
  60                 u32 temp[SHA_WORKSPACE_WORDS];
  61
  62                 if (partial) {
  63                         done = -partial;
  64                         memcpy(sctx->buffer + partial, data, done + 64);
  65                         src = sctx->buffer;
  66                 }
  67
  68                 do {
  69                         sha_transform(sctx->state, src, temp);
  70                         done += 64;
  71                         src = data + done;
  72                 } while (done + 63 < len);
  73
  74                 memset(temp, 0, sizeof(temp));
  75                 partial = 0;
  76         }
  77         memcpy(sctx->buffer + partial, src, len - done);
  78 }
  79
  80
  81 /* Add padding and return the message digest. */
  82 static void sha1_final(struct crypto_tfm *tfm, u8 *out)
  83 {
  84         struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
  85         __be32 *dst = (__be32 *)out;
  86         u32 i, index, padlen;
  87         __be64 bits;
  88         static const u8 padding[64] = { 0x80, };
  89
  90         bits = cpu_to_be64(sctx->count << 3);
  91
  92         /* Pad out to 56 mod 64 */
  93         index = sctx->count & 0x3f;
  94         padlen = (index < 56) ? (56 - index) : ((64+56) - index);
  95         sha1_update(tfm, padding, padlen);
  96
  97         /* Append length */
  98         sha1_update(tfm, (const u8 *)&bits, sizeof(bits));
  99
 100         /* Store state in digest */
 101         for (i = 0; i < 5; i++)
 102                 dst[i] = cpu_to_be32(sctx->state[i]);
 103
 104         /* Wipe context */
 105         memset(sctx, 0, sizeof *sctx);
 106 }
 107
 108 static struct crypto_alg alg = {
 109         .cra_name       =       "sha1",
 110         .cra_driver_name=       "sha1-generic",
 111         .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 112         .cra_blocksize  =       SHA1_BLOCK_SIZE,
 113         .cra_ctxsize    =       sizeof(struct sha1_ctx),
 114         .cra_module     =       THIS_MODULE,
 115         .cra_alignmask  =       3,
 116         .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
 117         .cra_u          =       { .digest = {
 118         .dia_digestsize =       SHA1_DIGEST_SIZE,
 119         .dia_init       =       sha1_init,
 120         .dia_update     =       sha1_update,
 121         .dia_final      =       sha1_final } }
 122 };
 123
 124 static int __init init(void)
 125 {
 126         return crypto_register_alg(&alg);
 127 }
 128
 129 static void __exit fini(void)
 130 {
 131         crypto_unregister_alg(&alg);
 132 }
 133
 134 module_init(init);
 135 module_exit(fini);
 136
 137 MODULE_LICENSE("GPL");
 138 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
 139
 140 MODULE_ALIAS("sha1");