crypto/md5.c

   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 MD5_DIGEST_WORDS 4
  27 #define MD5_MESSAGE_BYTES 64
  28
  29 const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = {
  30         0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
  31         0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e,
  32 };
  33 EXPORT_SYMBOL_GPL(md5_zero_message_hash);
  34
  35 /* XXX: this stuff can be optimized */
  36 static inline void le32_to_cpu_array(u32 *buf, unsigned int words)
  37 {
  38         while (words--) {
  39                 __le32_to_cpus(buf);
  40                 buf++;
  41         }
  42 }
  43
  44 static inline void cpu_to_le32_array(u32 *buf, unsigned int words)
  45 {
  46         while (words--) {
  47                 __cpu_to_le32s(buf);
  48                 buf++;
  49         }
  50 }
  51
  52 #define F1(x, y, z)     (z ^ (x & (y ^ z)))
  53 #define F2(x, y, z)     F1(z, x, y)
  54 #define F3(x, y, z)     (x ^ y ^ z)
  55 #define F4(x, y, z)     (y ^ (x | ~z))
  56
  57 #define MD5STEP(f, w, x, y, z, in, s) \
  58         (w += f(x, y, z) + in, w = (w<<s | w>>(32-s)) + x)
  59
  60 static void md5_transform(__u32 *hash, __u32 const *in)
  61 {
  62         u32 a, b, c, d;
  63
  64         a = hash[0];
  65         b = hash[1];
  66         c = hash[2];
  67         d = hash[3];
  68
  69         MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  70         MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  71         MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  72         MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  73         MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  74         MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  75         MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  76         MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  77         MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  78         MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  79         MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  80         MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  81         MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  82         MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  83         MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  84         MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
  85
  86         MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  87         MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  88         MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  89         MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  90         MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  91         MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  92         MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  93         MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  94         MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
  95         MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
  96         MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
  97         MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
  98         MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
  99         MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 100         MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 101         MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 102
 103         MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 104         MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 105         MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 106         MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 107         MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 108         MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 109         MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 110         MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 111         MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 112         MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 113         MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 114         MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 115         MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 116         MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 117         MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 118         MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 119
 120         MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 121         MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 122         MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 123         MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 124         MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 125         MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 126         MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 127         MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 128         MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 129         MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 130         MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 131         MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 132         MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 133         MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 134         MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 135         MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 136
 137         hash[0] += a;
 138         hash[1] += b;
 139         hash[2] += c;
 140         hash[3] += d;
 141 }
 142
 143 static inline void md5_transform_helper(struct md5_state *ctx)
 144 {
 145         le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
 146         md5_transform(ctx->hash, ctx->block);
 147 }
 148
 149 static int md5_init(struct shash_desc *desc)
 150 {
 151         struct md5_state *mctx = shash_desc_ctx(desc);
 152
 153         mctx->hash[0] = MD5_H0;
 154         mctx->hash[1] = MD5_H1;
 155         mctx->hash[2] = MD5_H2;
 156         mctx->hash[3] = MD5_H3;
 157         mctx->byte_count = 0;
 158
 159         return 0;
 160 }
 161
 162 static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len)
 163 {
 164         struct md5_state *mctx = shash_desc_ctx(desc);
 165         const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
 166
 167         mctx->byte_count += len;
 168
 169         if (avail > len) {
 170                 memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 171                        data, len);
 172                 return 0;
 173         }
 174
 175         memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
 176                data, avail);
 177
 178         md5_transform_helper(mctx);
 179         data += avail;
 180         len -= avail;
 181
 182         while (len >= sizeof(mctx->block)) {
 183                 memcpy(mctx->block, data, sizeof(mctx->block));
 184                 md5_transform_helper(mctx);
 185                 data += sizeof(mctx->block);
 186                 len -= sizeof(mctx->block);
 187         }
 188
 189         memcpy(mctx->block, data, len);
 190
 191         return 0;
 192 }
 193
 194 static int md5_final(struct shash_desc *desc, u8 *out)
 195 {
 196         struct md5_state *mctx = shash_desc_ctx(desc);
 197         const unsigned int offset = mctx->byte_count & 0x3f;
 198         char *p = (char *)mctx->block + offset;
 199         int padding = 56 - (offset + 1);
 200
 201         *p++ = 0x80;
 202         if (padding < 0) {
 203                 memset(p, 0x00, padding + sizeof (u64));
 204                 md5_transform_helper(mctx);
 205                 p = (char *)mctx->block;
 206                 padding = 56;
 207         }
 208
 209         memset(p, 0, padding);
 210         mctx->block[14] = mctx->byte_count << 3;
 211         mctx->block[15] = mctx->byte_count >> 29;
 212         le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
 213                           sizeof(u64)) / sizeof(u32));
 214         md5_transform(mctx->hash, mctx->block);
 215         cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));
 216         memcpy(out, mctx->hash, sizeof(mctx->hash));
 217         memset(mctx, 0, sizeof(*mctx));
 218
 219         return 0;
 220 }
 221
 222 static int md5_export(struct shash_desc *desc, void *out)
 223 {
 224         struct md5_state *ctx = shash_desc_ctx(desc);
 225
 226         memcpy(out, ctx, sizeof(*ctx));
 227         return 0;
 228 }
 229
 230 static int md5_import(struct shash_desc *desc, const void *in)
 231 {
 232         struct md5_state *ctx = shash_desc_ctx(desc);
 233
 234         memcpy(ctx, in, sizeof(*ctx));
 235         return 0;
 236 }
 237
 238 static struct shash_alg alg = {
 239         .digestsize     =       MD5_DIGEST_SIZE,
 240         .init           =       md5_init,
 241         .update         =       md5_update,
 242         .final          =       md5_final,
 243         .export         =       md5_export,
 244         .import         =       md5_import,
 245         .descsize       =       sizeof(struct md5_state),
 246         .statesize      =       sizeof(struct md5_state),
 247         .base           =       {
 248                 .cra_name       =       "md5",
 249                 .cra_flags      =       CRYPTO_ALG_TYPE_SHASH,
 250                 .cra_blocksize  =       MD5_HMAC_BLOCK_SIZE,
 251                 .cra_module     =       THIS_MODULE,
 252         }
 253 };
 254
 255 static int __init md5_mod_init(void)
 256 {
 257         return crypto_register_shash(&alg);
 258 }
 259
 260 static void __exit md5_mod_fini(void)
 261 {
 262         crypto_unregister_shash(&alg);
 263 }
 264
 265 module_init(md5_mod_init);
 266 module_exit(md5_mod_fini);
 267
 268 MODULE_LICENSE("GPL");
 269 MODULE_DESCRIPTION("MD5 Message Digest Algorithm");
 270 MODULE_ALIAS_CRYPTO("md5");