base/md5.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // The original file was copied from sqlite, and was in the public domain.
   6
   7 /*
   8  * This code implements the MD5 message-digest algorithm.
   9  * The algorithm is due to Ron Rivest.  This code was
  10  * written by Colin Plumb in 1993, no copyright is claimed.
  11  * This code is in the public domain; do with it what you wish.
  12  *
  13  * Equivalent code is available from RSA Data Security, Inc.
  14  * This code has been tested against that, and is equivalent,
  15  * except that you don't need to include two pages of legalese
  16  * with every copy.
  17  *
  18  * To compute the message digest of a chunk of bytes, declare an
  19  * MD5Context structure, pass it to MD5Init, call MD5Update as
  20  * needed on buffers full of bytes, and then call MD5Final, which
  21  * will fill a supplied 16-byte array with the digest.
  22  */
  23
  24 #include "base/md5.h"
  25
  26 #include <stddef.h>
  27
  28 namespace {
  29
  30 struct Context {
  31   uint32_t buf[4];
  32   uint32_t bits[2];
  33   uint8_t in[64];
  34 };
  35
  36 /*
  37  * Note: this code is harmless on little-endian machines.
  38  */
  39 void byteReverse(uint8_t* buf, unsigned longs) {
  40   uint32_t t;
  41   do {
  42     t = (uint32_t)((unsigned)buf[3] << 8 | buf[2]) << 16 |
  43         ((unsigned)buf[1] << 8 | buf[0]);
  44     *(uint32_t*)buf = t;
  45     buf += 4;
  46   } while (--longs);
  47 }
  48
  49 /* The four core functions - F1 is optimized somewhat */
  50
  51 /* #define F1(x, y, z) (x & y | ~x & z) */
  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 /* This is the central step in the MD5 algorithm. */
  58 #define MD5STEP(f, w, x, y, z, data, s) \
  59   (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)
  60
  61 /*
  62  * The core of the MD5 algorithm, this alters an existing MD5 hash to
  63  * reflect the addition of 16 longwords of new data.  MD5Update blocks
  64  * the data and converts bytes into longwords for this routine.
  65  */
  66 void MD5Transform(uint32_t buf[4], const uint32_t in[16]) {
  67   uint32_t a, b, c, d;
  68
  69   a = buf[0];
  70   b = buf[1];
  71   c = buf[2];
  72   d = buf[3];
  73
  74   MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  75   MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  76   MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  77   MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  78   MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  79   MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  80   MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  81   MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  82   MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  83   MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  84   MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  85   MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  86   MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  87   MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  88   MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  89   MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
  90
  91   MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  92   MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  93   MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  94   MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  95   MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  96   MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  97   MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  98   MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  99   MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 100   MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 101   MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 102   MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 103   MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 104   MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 105   MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 106   MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 107
 108   MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 109   MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 110   MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 111   MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 112   MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 113   MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 114   MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 115   MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 116   MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 117   MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 118   MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 119   MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 120   MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 121   MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 122   MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 123   MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 124
 125   MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 126   MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 127   MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 128   MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 129   MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 130   MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 131   MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 132   MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 133   MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 134   MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 135   MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 136   MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 137   MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 138   MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 139   MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 140   MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 141
 142   buf[0] += a;
 143   buf[1] += b;
 144   buf[2] += c;
 145   buf[3] += d;
 146 }
 147
 148 }  // namespace
 149
 150 namespace base {
 151
 152 /*
 153  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 154  * initialization constants.
 155  */
 156 void MD5Init(MD5Context* context) {
 157   struct Context* ctx = (struct Context*)context;
 158   ctx->buf[0] = 0x67452301;
 159   ctx->buf[1] = 0xefcdab89;
 160   ctx->buf[2] = 0x98badcfe;
 161   ctx->buf[3] = 0x10325476;
 162   ctx->bits[0] = 0;
 163   ctx->bits[1] = 0;
 164 }
 165
 166 /*
 167  * Update context to reflect the concatenation of another buffer full
 168  * of bytes.
 169  */
 170 void MD5Update(MD5Context* context, const StringPiece& data) {
 171   const uint8_t* inbuf = (const uint8_t*)data.data();
 172   size_t len = data.size();
 173   struct Context* ctx = (struct Context*)context;
 174   const uint8_t* buf = (const uint8_t*)inbuf;
 175   uint32_t t;
 176
 177   /* Update bitcount */
 178
 179   t = ctx->bits[0];
 180   if ((ctx->bits[0] = t + ((uint32_t)len << 3)) < t)
 181     ctx->bits[1]++; /* Carry from low to high */
 182   ctx->bits[1] += static_cast<uint32_t>(len >> 29);
 183
 184   t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
 185
 186   /* Handle any leading odd-sized chunks */
 187
 188   if (t) {
 189     uint8_t* p = (uint8_t*)ctx->in + t;
 190
 191     t = 64 - t;
 192     if (len < t) {
 193       memcpy(p, buf, len);
 194       return;
 195     }
 196     memcpy(p, buf, t);
 197     byteReverse(ctx->in, 16);
 198     MD5Transform(ctx->buf, (uint32_t*)ctx->in);
 199     buf += t;
 200     len -= t;
 201   }
 202
 203   /* Process data in 64-byte chunks */
 204
 205   while (len >= 64) {
 206     memcpy(ctx->in, buf, 64);
 207     byteReverse(ctx->in, 16);
 208     MD5Transform(ctx->buf, (uint32_t*)ctx->in);
 209     buf += 64;
 210     len -= 64;
 211   }
 212
 213   /* Handle any remaining bytes of data. */
 214
 215   memcpy(ctx->in, buf, len);
 216 }
 217
 218 /*
 219  * Final wrapup - pad to 64-byte boundary with the bit pattern
 220  * 1 0* (64-bit count of bits processed, MSB-first)
 221  */
 222 void MD5Final(MD5Digest* digest, MD5Context* context) {
 223   struct Context* ctx = (struct Context*)context;
 224   unsigned count;
 225   uint8_t* p;
 226
 227   /* Compute number of bytes mod 64 */
 228   count = (ctx->bits[0] >> 3) & 0x3F;
 229
 230   /* Set the first char of padding to 0x80.  This is safe since there is
 231      always at least one byte free */
 232   p = ctx->in + count;
 233   *p++ = 0x80;
 234
 235   /* Bytes of padding needed to make 64 bytes */
 236   count = 64 - 1 - count;
 237
 238   /* Pad out to 56 mod 64 */
 239   if (count < 8) {
 240     /* Two lots of padding:  Pad the first block to 64 bytes */
 241     memset(p, 0, count);
 242     byteReverse(ctx->in, 16);
 243     MD5Transform(ctx->buf, (uint32_t*)ctx->in);
 244
 245     /* Now fill the next block with 56 bytes */
 246     memset(ctx->in, 0, 56);
 247   } else {
 248     /* Pad block to 56 bytes */
 249     memset(p, 0, count - 8);
 250   }
 251   byteReverse(ctx->in, 14);
 252
 253   /* Append length in bits and transform */
 254   memcpy(&ctx->in[14 * sizeof(ctx->bits[0])], &ctx->bits[0],
 255          sizeof(ctx->bits[0]));
 256   memcpy(&ctx->in[15 * sizeof(ctx->bits[1])], &ctx->bits[1],
 257          sizeof(ctx->bits[1]));
 258
 259   MD5Transform(ctx->buf, (uint32_t*)ctx->in);
 260   byteReverse((uint8_t*)ctx->buf, 4);
 261   memcpy(digest->a, ctx->buf, 16);
 262   memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
 263 }
 264
 265 void MD5IntermediateFinal(MD5Digest* digest, const MD5Context* context) {
 266   /* MD5Final mutates the MD5Context*. Make a copy for generating the
 267      intermediate value. */
 268   MD5Context context_copy;
 269   memcpy(&context_copy, context, sizeof(context_copy));
 270   MD5Final(digest, &context_copy);
 271 }
 272
 273 std::string MD5DigestToBase16(const MD5Digest& digest) {
 274   static char const zEncode[] = "0123456789abcdef";
 275
 276   std::string ret;
 277   ret.resize(32);
 278
 279   for (int i = 0, j = 0; i < 16; i++, j += 2) {
 280     uint8_t a = digest.a[i];
 281     ret[j] = zEncode[(a >> 4) & 0xf];
 282     ret[j + 1] = zEncode[a & 0xf];
 283   }
 284   return ret;
 285 }
 286
 287 void MD5Sum(const void* data, size_t length, MD5Digest* digest) {
 288   MD5Context ctx;
 289   MD5Init(&ctx);
 290   MD5Update(&ctx, StringPiece(reinterpret_cast<const char*>(data), length));
 291   MD5Final(digest, &ctx);
 292 }
 293
 294 std::string MD5String(const StringPiece& str) {
 295   MD5Digest digest;
 296   MD5Sum(str.data(), str.length(), &digest);
 297   return MD5DigestToBase16(digest);
 298 }
 299
 300 }  // namespace base