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 "base/basictypes.h"
  27
  28 namespace {
  29
  30 struct Context {
  31   uint32 buf[4];
  32   uint32 bits[2];
  33   unsigned char in[64];
  34 };
  35
  36 /*
  37  * Note: this code is harmless on little-endian machines.
  38  */
  39 void byteReverse(unsigned char *buf, unsigned longs) {
  40         uint32 t;
  41         do {
  42                 t = (uint32)((unsigned)buf[3]<<8 | buf[2]) << 16 |
  43                             ((unsigned)buf[1]<<8 | buf[0]);
  44                 *(uint32 *)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 buf[4], const uint32 in[16]) {
  67         register uint32 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 unsigned char* inbuf = (const unsigned char*)data.data();
 172         size_t len = data.size();
 173         struct Context *ctx = (struct Context *)context;
 174         const unsigned char* buf = (const unsigned char*)inbuf;
 175         uint32 t;
 176
 177         /* Update bitcount */
 178
 179         t = ctx->bits[0];
 180         if ((ctx->bits[0] = t + ((uint32)len << 3)) < t)
 181                 ctx->bits[1]++; /* Carry from low to high */
 182         ctx->bits[1] += static_cast<uint32>(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                 unsigned char *p = (unsigned char *)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 *)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 *)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         unsigned char *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 *)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         ((uint32 *)ctx->in)[ 14 ] = ctx->bits[0];
 255         ((uint32 *)ctx->in)[ 15 ] = ctx->bits[1];
 256
 257         MD5Transform(ctx->buf, (uint32 *)ctx->in);
 258         byteReverse((unsigned char *)ctx->buf, 4);
 259         memcpy(digest->a, ctx->buf, 16);
 260         memset(ctx, 0, sizeof(*ctx));    /* In case it's sensitive */
 261 }
 262
 263 void MD5IntermediateFinal(MD5Digest* digest, const MD5Context* context) {
 264   /* MD5Final mutates the MD5Context*. Make a copy for generating the
 265      intermediate value. */
 266   MD5Context context_copy;
 267   memcpy(&context_copy, context, sizeof(context_copy));
 268   MD5Final(digest, &context_copy);
 269 }
 270
 271 std::string MD5DigestToBase16(const MD5Digest& digest) {
 272   static char const zEncode[] = "0123456789abcdef";
 273
 274   std::string ret;
 275   ret.resize(32);
 276
 277   int j = 0;
 278   for (int i = 0; i < 16; i ++) {
 279     int a = digest.a[i];
 280     ret[j++] = zEncode[(a>>4)&0xf];
 281     ret[j++] = zEncode[a & 0xf];
 282   }
 283   return ret;
 284 }
 285
 286 void MD5Sum(const void* data, size_t length, MD5Digest* digest) {
 287   MD5Context ctx;
 288   MD5Init(&ctx);
 289   MD5Update(&ctx,
 290             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