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 <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
  28 static 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
  39 static 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. */
  76 static 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
 104 static 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
 112 static 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
 120 static 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
 138 static int __init sha1_generic_mod_init(void)
 139 {
 140         return crypto_register_shash(&alg);
 141 }
 142
 143 static void __exit sha1_generic_mod_fini(void)
 144 {
 145         crypto_unregister_shash(&alg);
 146 }
 147
 148 module_init(sha1_generic_mod_init);
 149 module_exit(sha1_generic_mod_fini);
 150
 151 MODULE_LICENSE("GPL");
 152 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
 153
 154 MODULE_ALIAS("sha1");