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