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      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 std::string MD5DigestToBase16(const MD5Digest& digest) {
    264   static char const zEncode[] = "0123456789abcdef";
    265 
    266   std::string ret;
    267   ret.resize(32);
    268 
    269   int j = 0;
    270   for (int i = 0; i < 16; i ++) {
    271     int a = digest.a[i];
    272     ret[j++] = zEncode[(a>>4)&0xf];
    273     ret[j++] = zEncode[a & 0xf];
    274   }
    275   return ret;
    276 }
    277 
    278 void MD5Sum(const void* data, size_t length, MD5Digest* digest) {
    279   MD5Context ctx;
    280   MD5Init(&ctx);
    281   MD5Update(&ctx,
    282             StringPiece(reinterpret_cast<const char*>(data), length));
    283   MD5Final(digest, &ctx);
    284 }
    285 
    286 std::string MD5String(const StringPiece& str) {
    287   MD5Digest digest;
    288   MD5Sum(str.data(), str.length(), &digest);
    289   return MD5DigestToBase16(digest);
    290 }
    291 
    292 }  // namespace base
    293