linux/crypto/md5.c
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   1/* 
   2 * Cryptographic API.
   3 *
   4 * MD5 Message Digest Algorithm (RFC1321).
   5 *
   6 * Derived from cryptoapi implementation, originally based on the
   7 * public domain implementation written by Colin Plumb in 1993.
   8 *
   9 * Copyright (c) Cryptoapi developers.
  10 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  11 * 
  12 * This program is free software; you can redistribute it and/or modify it
  13 * under the terms of the GNU General Public License as published by the Free
  14 * Software Foundation; either version 2 of the License, or (at your option) 
  15 * any later version.
  16 *
  17 */
  18#include <crypto/internal/hash.h>
  19#include <crypto/md5.h>
  20#include <linux/init.h>
  21#include <linux/module.h>
  22#include <linux/string.h>
  23#include <linux/types.h>
  24#include <asm/byteorder.h>
  25
  26const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = {
  27        0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
  28        0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e,
  29};
  30EXPORT_SYMBOL_GPL(md5_zero_message_hash);
  31
  32#define F1(x, y, z)     (z ^ (x & (y ^ z)))
  33#define F2(x, y, z)     F1(z, x, y)
  34#define F3(x, y, z)     (x ^ y ^ z)
  35#define F4(x, y, z)     (y ^ (x | ~z))
  36
  37#define MD5STEP(f, w, x, y, z, in, s) \
  38        (w += f(x, y, z) + in, w = (w<<s | w>>(32-s)) + x)
  39
  40static void md5_transform(__u32 *hash, __u32 const *in)
  41{
  42        u32 a, b, c, d;
  43
  44        a = hash[0];
  45        b = hash[1];
  46        c = hash[2];
  47        d = hash[3];
  48
  49        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  50        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  51        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  52        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  53        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  54        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  55        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  56        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  57        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  58        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  59        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  60        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  61        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  62        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  63        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  64        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
  65
  66        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  67        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  68        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  69        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  70        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  71        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  72        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  73        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  74        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
  75        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
  76        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
  77        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
  78        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
  79        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
  80        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
  81        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
  82
  83        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
  84        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
  85        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
  86        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
  87        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
  88        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
  89        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
  90        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
  91        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
  92        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
  93        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
  94        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
  95        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
  96        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
  97        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
  98        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
  99
 100        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 101        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 102        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 103        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 104        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 105        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 106        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 107        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 108        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 109        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 110        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 111        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 112        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 113        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 114        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 115        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 116
 117        hash[0] += a;
 118        hash[1] += b;
 119        hash[2] += c;
 120        hash[3] += d;
 121}
 122
 123static inline void md5_transform_helper(struct md5_state *ctx)
 124{
 125        le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
 126        md5_transform(ctx->hash, ctx->block);
 127}
 128
 129static int md5_init(struct shash_desc *desc)
 130{
 131        struct md5_state *mctx = shash_desc_ctx(desc);
 132
 133        mctx->hash[0] = MD5_H0;
 134        mctx->hash[1] = MD5_H1;
 135        mctx->hash[2] = MD5_H2;
 136        mctx->hash[3] = MD5_H3;
 137        mctx->byte_count = 0;
 138
 139        return 0;
 140}
 141
 142static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len)
 143{
 144        struct md5_state *mctx = shash_desc_ctx(desc);
 145        const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
 146
 147        mctx->byte_count += len;
 148
 149        if (avail > len) {
 150                memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 151                       data, len);
 152                return 0;
 153        }
 154
 155        memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 156               data, avail);
 157
 158        md5_transform_helper(mctx);
 159        data += avail;
 160        len -= avail;
 161
 162        while (len >= sizeof(mctx->block)) {
 163                memcpy(mctx->block, data, sizeof(mctx->block));
 164                md5_transform_helper(mctx);
 165                data += sizeof(mctx->block);
 166                len -= sizeof(mctx->block);
 167        }
 168
 169        memcpy(mctx->block, data, len);
 170
 171        return 0;
 172}
 173
 174static int md5_final(struct shash_desc *desc, u8 *out)
 175{
 176        struct md5_state *mctx = shash_desc_ctx(desc);
 177        const unsigned int offset = mctx->byte_count & 0x3f;
 178        char *p = (char *)mctx->block + offset;
 179        int padding = 56 - (offset + 1);
 180
 181        *p++ = 0x80;
 182        if (padding < 0) {
 183                memset(p, 0x00, padding + sizeof (u64));
 184                md5_transform_helper(mctx);
 185                p = (char *)mctx->block;
 186                padding = 56;
 187        }
 188
 189        memset(p, 0, padding);
 190        mctx->block[14] = mctx->byte_count << 3;
 191        mctx->block[15] = mctx->byte_count >> 29;
 192        le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
 193                          sizeof(u64)) / sizeof(u32));
 194        md5_transform(mctx->hash, mctx->block);
 195        cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));
 196        memcpy(out, mctx->hash, sizeof(mctx->hash));
 197        memset(mctx, 0, sizeof(*mctx));
 198
 199        return 0;
 200}
 201
 202static int md5_export(struct shash_desc *desc, void *out)
 203{
 204        struct md5_state *ctx = shash_desc_ctx(desc);
 205
 206        memcpy(out, ctx, sizeof(*ctx));
 207        return 0;
 208}
 209
 210static int md5_import(struct shash_desc *desc, const void *in)
 211{
 212        struct md5_state *ctx = shash_desc_ctx(desc);
 213
 214        memcpy(ctx, in, sizeof(*ctx));
 215        return 0;
 216}
 217
 218static struct shash_alg alg = {
 219        .digestsize     =       MD5_DIGEST_SIZE,
 220        .init           =       md5_init,
 221        .update         =       md5_update,
 222        .final          =       md5_final,
 223        .export         =       md5_export,
 224        .import         =       md5_import,
 225        .descsize       =       sizeof(struct md5_state),
 226        .statesize      =       sizeof(struct md5_state),
 227        .base           =       {
 228                .cra_name        =      "md5",
 229                .cra_driver_name =      "md5-generic",
 230                .cra_blocksize   =      MD5_HMAC_BLOCK_SIZE,
 231                .cra_module      =      THIS_MODULE,
 232        }
 233};
 234
 235static int __init md5_mod_init(void)
 236{
 237        return crypto_register_shash(&alg);
 238}
 239
 240static void __exit md5_mod_fini(void)
 241{
 242        crypto_unregister_shash(&alg);
 243}
 244
 245subsys_initcall(md5_mod_init);
 246module_exit(md5_mod_fini);
 247
 248MODULE_LICENSE("GPL");
 249MODULE_DESCRIPTION("MD5 Message Digest Algorithm");
 250MODULE_ALIAS_CRYPTO("md5");
 251
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