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 <linux/init.h>
  19#include <linux/module.h>
  20#include <linux/string.h>
  21#include <linux/crypto.h>
  22#include <linux/types.h>
  23#include <asm/byteorder.h>
  24
  25#define MD5_DIGEST_SIZE         16
  26#define MD5_HMAC_BLOCK_SIZE     64
  27#define MD5_BLOCK_WORDS         16
  28#define MD5_HASH_WORDS          4
  29
  30#define F1(x, y, z)     (z ^ (x & (y ^ z)))
  31#define F2(x, y, z)     F1(z, x, y)
  32#define F3(x, y, z)     (x ^ y ^ z)
  33#define F4(x, y, z)     (y ^ (x | ~z))
  34
  35#define MD5STEP(f, w, x, y, z, in, s) \
  36        (w += f(x, y, z) + in, w = (w<<s | w>>(32-s)) + x)
  37
  38struct md5_ctx {
  39        u32 hash[MD5_HASH_WORDS];
  40        u32 block[MD5_BLOCK_WORDS];
  41        u64 byte_count;
  42};
  43
  44static void md5_transform(u32 *hash, u32 const *in)
  45{
  46        u32 a, b, c, d;
  47
  48        a = hash[0];
  49        b = hash[1];
  50        c = hash[2];
  51        d = hash[3];
  52
  53        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  54        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  55        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  56        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  57        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  58        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  59        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  60        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  61        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  62        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  63        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  64        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  65        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  66        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  67        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  68        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
  69
  70        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  71        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  72        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  73        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  74        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  75        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  76        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  77        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  78        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
  79        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
  80        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
  81        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
  82        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
  83        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
  84        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
  85        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
  86
  87        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
  88        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
  89        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
  90        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
  91        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
  92        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
  93        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
  94        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
  95        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
  96        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
  97        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
  98        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
  99        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 100        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 101        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 102        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 103
 104        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 105        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 106        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 107        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 108        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 109        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 110        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 111        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 112        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 113        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 114        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 115        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 116        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 117        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 118        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 119        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 120
 121        hash[0] += a;
 122        hash[1] += b;
 123        hash[2] += c;
 124        hash[3] += d;
 125}
 126
 127/* XXX: this stuff can be optimized */
 128static inline void le32_to_cpu_array(u32 *buf, unsigned int words)
 129{
 130        while (words--) {
 131                __le32_to_cpus(buf);
 132                buf++;
 133        }
 134}
 135
 136static inline void cpu_to_le32_array(u32 *buf, unsigned int words)
 137{
 138        while (words--) {
 139                __cpu_to_le32s(buf);
 140                buf++;
 141        }
 142}
 143
 144static inline void md5_transform_helper(struct md5_ctx *ctx)
 145{
 146        le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
 147        md5_transform(ctx->hash, ctx->block);
 148}
 149
 150static void md5_init(struct crypto_tfm *tfm)
 151{
 152        struct md5_ctx *mctx = crypto_tfm_ctx(tfm);
 153
 154        mctx->hash[0] = 0x67452301;
 155        mctx->hash[1] = 0xefcdab89;
 156        mctx->hash[2] = 0x98badcfe;
 157        mctx->hash[3] = 0x10325476;
 158        mctx->byte_count = 0;
 159}
 160
 161static void md5_update(struct crypto_tfm *tfm, const u8 *data, unsigned int len)
 162{
 163        struct md5_ctx *mctx = crypto_tfm_ctx(tfm);
 164        const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
 165
 166        mctx->byte_count += len;
 167
 168        if (avail > len) {
 169                memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 170                       data, len);
 171                return;
 172        }
 173
 174        memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 175               data, avail);
 176
 177        md5_transform_helper(mctx);
 178        data += avail;
 179        len -= avail;
 180
 181        while (len >= sizeof(mctx->block)) {
 182                memcpy(mctx->block, data, sizeof(mctx->block));
 183                md5_transform_helper(mctx);
 184                data += sizeof(mctx->block);
 185                len -= sizeof(mctx->block);
 186        }
 187
 188        memcpy(mctx->block, data, len);
 189}
 190
 191static void md5_final(struct crypto_tfm *tfm, u8 *out)
 192{
 193        struct md5_ctx *mctx = crypto_tfm_ctx(tfm);
 194        const unsigned int offset = mctx->byte_count & 0x3f;
 195        char *p = (char *)mctx->block + offset;
 196        int padding = 56 - (offset + 1);
 197
 198        *p++ = 0x80;
 199        if (padding < 0) {
 200                memset(p, 0x00, padding + sizeof (u64));
 201                md5_transform_helper(mctx);
 202                p = (char *)mctx->block;
 203                padding = 56;
 204        }
 205
 206        memset(p, 0, padding);
 207        mctx->block[14] = mctx->byte_count << 3;
 208        mctx->block[15] = mctx->byte_count >> 29;
 209        le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
 210                          sizeof(u64)) / sizeof(u32));
 211        md5_transform(mctx->hash, mctx->block);
 212        cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));
 213        memcpy(out, mctx->hash, sizeof(mctx->hash));
 214        memset(mctx, 0, sizeof(*mctx));
 215}
 216
 217static struct crypto_alg alg = {
 218        .cra_name       =       "md5",
 219        .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 220        .cra_blocksize  =       MD5_HMAC_BLOCK_SIZE,
 221        .cra_ctxsize    =       sizeof(struct md5_ctx),
 222        .cra_module     =       THIS_MODULE,
 223        .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
 224        .cra_u          =       { .digest = {
 225        .dia_digestsize =       MD5_DIGEST_SIZE,
 226        .dia_init       =       md5_init,
 227        .dia_update     =       md5_update,
 228        .dia_final      =       md5_final } }
 229};
 230
 231static int __init init(void)
 232{
 233        return crypto_register_alg(&alg);
 234}
 235
 236static void __exit fini(void)
 237{
 238        crypto_unregister_alg(&alg);
 239}
 240
 241module_init(init);
 242module_exit(fini);
 243
 244MODULE_LICENSE("GPL");
 245MODULE_DESCRIPTION("MD5 Message Digest Algorithm");
 246
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