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 <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
  38 struct md5_ctx {
  39         u32 hash[MD5_HASH_WORDS];
  40         u32 block[MD5_BLOCK_WORDS];
  41         u64 byte_count;
  42 };
  43
  44 static 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 */
 128 static 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
 136 static 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
 144 static 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
 150 static 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
 161 static 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
 191 static 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
 217 static 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
 231 static int __init init(void)
 232 {
 233         return crypto_register_alg(&alg);
 234 }
 235
 236 static void __exit fini(void)
 237 {
 238         crypto_unregister_alg(&alg);
 239 }
 240
 241 module_init(init);
 242 module_exit(fini);
 243
 244 MODULE_LICENSE("GPL");
 245 MODULE_DESCRIPTION("MD5 Message Digest Algorithm");