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
  26#define F1(x, y, z)     (z ^ (x & (y ^ z)))
  27#define F2(x, y, z)     F1(z, x, y)
  28#define F3(x, y, z)     (x ^ y ^ z)
  29#define F4(x, y, z)     (y ^ (x | ~z))
  30
  31#define MD5STEP(f, w, x, y, z, in, s) \
  32        (w += f(x, y, z) + in, w = (w<<s | w>>(32-s)) + x)
  33
  34static void md5_transform(u32 *hash, u32 const *in)
  35{
  36        u32 a, b, c, d;
  37
  38        a = hash[0];
  39        b = hash[1];
  40        c = hash[2];
  41        d = hash[3];
  42
  43        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  44        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  45        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  46        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  47        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  48        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  49        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  50        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  51        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  52        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  53        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  54        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  55        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  56        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  57        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  58        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
  59
  60        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  61        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  62        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  63        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  64        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  65        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  66        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  67        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  68        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
  69        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
  70        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
  71        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
  72        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
  73        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
  74        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
  75        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
  76
  77        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
  78        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
  79        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
  80        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
  81        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
  82        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
  83        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
  84        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
  85        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
  86        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
  87        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
  88        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
  89        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
  90        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
  91        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
  92        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
  93
  94        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
  95        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
  96        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
  97        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
  98        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
  99        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 100        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 101        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 102        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 103        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 104        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 105        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 106        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 107        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 108        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 109        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 110
 111        hash[0] += a;
 112        hash[1] += b;
 113        hash[2] += c;
 114        hash[3] += d;
 115}
 116
 117/* XXX: this stuff can be optimized */
 118static inline void le32_to_cpu_array(u32 *buf, unsigned int words)
 119{
 120        while (words--) {
 121                __le32_to_cpus(buf);
 122                buf++;
 123        }
 124}
 125
 126static inline void cpu_to_le32_array(u32 *buf, unsigned int words)
 127{
 128        while (words--) {
 129                __cpu_to_le32s(buf);
 130                buf++;
 131        }
 132}
 133
 134static inline void md5_transform_helper(struct md5_state *ctx)
 135{
 136        le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
 137        md5_transform(ctx->hash, ctx->block);
 138}
 139
 140static int md5_init(struct shash_desc *desc)
 141{
 142        struct md5_state *mctx = shash_desc_ctx(desc);
 143
 144        mctx->hash[0] = 0x67452301;
 145        mctx->hash[1] = 0xefcdab89;
 146        mctx->hash[2] = 0x98badcfe;
 147        mctx->hash[3] = 0x10325476;
 148        mctx->byte_count = 0;
 149
 150        return 0;
 151}
 152
 153static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len)
 154{
 155        struct md5_state *mctx = shash_desc_ctx(desc);
 156        const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
 157
 158        mctx->byte_count += len;
 159
 160        if (avail > len) {
 161                memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 162                       data, len);
 163                return 0;
 164        }
 165
 166        memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 167               data, avail);
 168
 169        md5_transform_helper(mctx);
 170        data += avail;
 171        len -= avail;
 172
 173        while (len >= sizeof(mctx->block)) {
 174                memcpy(mctx->block, data, sizeof(mctx->block));
 175                md5_transform_helper(mctx);
 176                data += sizeof(mctx->block);
 177                len -= sizeof(mctx->block);
 178        }
 179
 180        memcpy(mctx->block, data, len);
 181
 182        return 0;
 183}
 184
 185static int md5_final(struct shash_desc *desc, u8 *out)
 186{
 187        struct md5_state *mctx = shash_desc_ctx(desc);
 188        const unsigned int offset = mctx->byte_count & 0x3f;
 189        char *p = (char *)mctx->block + offset;
 190        int padding = 56 - (offset + 1);
 191
 192        *p++ = 0x80;
 193        if (padding < 0) {
 194                memset(p, 0x00, padding + sizeof (u64));
 195                md5_transform_helper(mctx);
 196                p = (char *)mctx->block;
 197                padding = 56;
 198        }
 199
 200        memset(p, 0, padding);
 201        mctx->block[14] = mctx->byte_count << 3;
 202        mctx->block[15] = mctx->byte_count >> 29;
 203        le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
 204                          sizeof(u64)) / sizeof(u32));
 205        md5_transform(mctx->hash, mctx->block);
 206        cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));
 207        memcpy(out, mctx->hash, sizeof(mctx->hash));
 208        memset(mctx, 0, sizeof(*mctx));
 209
 210        return 0;
 211}
 212
 213static int md5_export(struct shash_desc *desc, void *out)
 214{
 215        struct md5_state *ctx = shash_desc_ctx(desc);
 216
 217        memcpy(out, ctx, sizeof(*ctx));
 218        return 0;
 219}
 220
 221static int md5_import(struct shash_desc *desc, const void *in)
 222{
 223        struct md5_state *ctx = shash_desc_ctx(desc);
 224
 225        memcpy(ctx, in, sizeof(*ctx));
 226        return 0;
 227}
 228
 229static struct shash_alg alg = {
 230        .digestsize     =       MD5_DIGEST_SIZE,
 231        .init           =       md5_init,
 232        .update         =       md5_update,
 233        .final          =       md5_final,
 234        .export         =       md5_export,
 235        .import         =       md5_import,
 236        .descsize       =       sizeof(struct md5_state),
 237        .statesize      =       sizeof(struct md5_state),
 238        .base           =       {
 239                .cra_name       =       "md5",
 240                .cra_flags      =       CRYPTO_ALG_TYPE_SHASH,
 241                .cra_blocksize  =       MD5_HMAC_BLOCK_SIZE,
 242                .cra_module     =       THIS_MODULE,
 243        }
 244};
 245
 246static int __init md5_mod_init(void)
 247{
 248        return crypto_register_shash(&alg);
 249}
 250
 251static void __exit md5_mod_fini(void)
 252{
 253        crypto_unregister_shash(&alg);
 254}
 255
 256module_init(md5_mod_init);
 257module_exit(md5_mod_fini);
 258
 259MODULE_LICENSE("GPL");
 260MODULE_DESCRIPTION("MD5 Message Digest Algorithm");
 261