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(struct crypto_tfm *tfm)
  38 {
  39         struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
  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(struct crypto_tfm *tfm, const u8 *data,
  50                         unsigned int len)
  51 {
  52         struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
  53         unsigned int partial, done;
  54         const u8 *src;
  55
  56         partial = sctx->count & 0x3f;
  57         sctx->count += len;
  58         done = 0;
  59         src = data;
  60
  61         if ((partial + len) > 63) {
  62                 u32 temp[SHA_WORKSPACE_WORDS];
  63
  64                 if (partial) {
  65                         done = -partial;
  66                         memcpy(sctx->buffer + partial, data, done + 64);
  67                         src = sctx->buffer;
  68                 }
  69
  70                 do {
  71                         sha_transform(sctx->state, src, temp);
  72                         done += 64;
  73                         src = data + done;
  74                 } while (done + 63 < len);
  75
  76                 memset(temp, 0, sizeof(temp));
  77                 partial = 0;
  78         }
  79         memcpy(sctx->buffer + partial, src, len - done);
  80 }
  81
  82
  83 /* Add padding and return the message digest. */
  84 static void sha1_final(struct crypto_tfm *tfm, u8 *out)
  85 {
  86         struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
  87         __be32 *dst = (__be32 *)out;
  88         u32 i, index, padlen;
  89         __be64 bits;
  90         static const u8 padding[64] = { 0x80, };
  91
  92         bits = cpu_to_be64(sctx->count << 3);
  93
  94         /* Pad out to 56 mod 64 */
  95         index = sctx->count & 0x3f;
  96         padlen = (index < 56) ? (56 - index) : ((64+56) - index);
  97         sha1_update(tfm, padding, padlen);
  98
  99         /* Append length */
 100         sha1_update(tfm, (const u8 *)&bits, sizeof(bits));
 101
 102         /* Store state in digest */
 103         for (i = 0; i < 5; i++)
 104                 dst[i] = cpu_to_be32(sctx->state[i]);
 105
 106         /* Wipe context */
 107         memset(sctx, 0, sizeof *sctx);
 108 }
 109
 110 static struct crypto_alg alg = {
 111         .cra_name       =       "sha1",
 112         .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 113         .cra_blocksize  =       SHA1_HMAC_BLOCK_SIZE,
 114         .cra_ctxsize    =       sizeof(struct sha1_ctx),
 115         .cra_module     =       THIS_MODULE,
 116         .cra_alignmask  =       3,
 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");