1 /* 2 * This code implements the MD5 message-digest algorithm. 3 * The algorithm is due to Ron Rivest. This code was 4 * written by Colin Plumb in 1993, no copyright is claimed. 5 * This code is in the public domain; do with it what you wish. 6 * 7 * Equivalent code is available from RSA Data Security, Inc. 8 * This code has been tested against that, and is equivalent, 9 * except that you don't need to include two pages of legalese 10 * with every copy. 11 * 12 * To compute the message digest of a chunk of bytes, declare an 13 * MD5Context structure, pass it to MD5Init, call MD5Update as 14 * needed on buffers full of bytes, and then call MD5Final, which 15 * will fill a supplied 16-byte array with the digest. 16 */ 17 18 // Changes from original C code: 19 // Ported to C++, type casting, Google code style. 20 21 #include "talk/base/md5.h" 22 23 // TODO: Avoid memcmpy - hash directly from memory. 24 #include <string.h> // for memcpy(). 25 26 #include "talk/base/byteorder.h" // for ARCH_CPU_LITTLE_ENDIAN. 27 28 #ifdef ARCH_CPU_LITTLE_ENDIAN 29 #define ByteReverse(buf, len) // Nothing. 30 #else // ARCH_CPU_BIG_ENDIAN 31 static void ByteReverse(uint32* buf, int len) { 32 for (int i = 0; i < len; ++i) { 33 buf[i] = talk_base::GetLE32(&buf[i]); 34 } 35 } 36 #endif 37 38 // Start MD5 accumulation. Set bit count to 0 and buffer to mysterious 39 // initialization constants. 40 void MD5Init(MD5Context* ctx) { 41 ctx->buf[0] = 0x67452301; 42 ctx->buf[1] = 0xefcdab89; 43 ctx->buf[2] = 0x98badcfe; 44 ctx->buf[3] = 0x10325476; 45 ctx->bits[0] = 0; 46 ctx->bits[1] = 0; 47 } 48 49 // Update context to reflect the concatenation of another buffer full of bytes. 50 void MD5Update(MD5Context* ctx, const uint8* buf, size_t len) { 51 // Update bitcount. 52 uint32 t = ctx->bits[0]; 53 if ((ctx->bits[0] = t + (static_cast<uint32>(len) << 3)) < t) { 54 ctx->bits[1]++; // Carry from low to high. 55 } 56 ctx->bits[1] += static_cast<uint32>(len >> 29); 57 t = (t >> 3) & 0x3f; // Bytes already in shsInfo->data. 58 59 // Handle any leading odd-sized chunks. 60 if (t) { 61 uint8* p = reinterpret_cast<uint8*>(ctx->in) + t; 62 63 t = 64-t; 64 if (len < t) { 65 memcpy(p, buf, len); 66 return; 67 } 68 memcpy(p, buf, t); 69 ByteReverse(ctx->in, 16); 70 MD5Transform(ctx->buf, ctx->in); 71 buf += t; 72 len -= t; 73 } 74 75 // Process data in 64-byte chunks. 76 while (len >= 64) { 77 memcpy(ctx->in, buf, 64); 78 ByteReverse(ctx->in, 16); 79 MD5Transform(ctx->buf, ctx->in); 80 buf += 64; 81 len -= 64; 82 } 83 84 // Handle any remaining bytes of data. 85 memcpy(ctx->in, buf, len); 86 } 87 88 // Final wrapup - pad to 64-byte boundary with the bit pattern. 89 // 1 0* (64-bit count of bits processed, MSB-first) 90 void MD5Final(MD5Context* ctx, uint8 digest[16]) { 91 // Compute number of bytes mod 64. 92 uint32 count = (ctx->bits[0] >> 3) & 0x3F; 93 94 // Set the first char of padding to 0x80. This is safe since there is 95 // always at least one byte free. 96 uint8* p = reinterpret_cast<uint8*>(ctx->in) + count; 97 *p++ = 0x80; 98 99 // Bytes of padding needed to make 64 bytes. 100 count = 64 - 1 - count; 101 102 // Pad out to 56 mod 64. 103 if (count < 8) { 104 // Two lots of padding: Pad the first block to 64 bytes. 105 memset(p, 0, count); 106 ByteReverse(ctx->in, 16); 107 MD5Transform(ctx->buf, ctx->in); 108 109 // Now fill the next block with 56 bytes. 110 memset(ctx->in, 0, 56); 111 } else { 112 // Pad block to 56 bytes. 113 memset(p, 0, count - 8); 114 } 115 ByteReverse(ctx->in, 14); 116 117 // Append length in bits and transform. 118 ctx->in[14] = ctx->bits[0]; 119 ctx->in[15] = ctx->bits[1]; 120 121 MD5Transform(ctx->buf, ctx->in); 122 ByteReverse(ctx->buf, 4); 123 memcpy(digest, ctx->buf, 16); 124 memset(ctx, 0, sizeof(*ctx)); // In case it's sensitive. 125 } 126 127 // The four core functions - F1 is optimized somewhat. 128 // #define F1(x, y, z) (x & y | ~x & z) 129 #define F1(x, y, z) (z ^ (x & (y ^ z))) 130 #define F2(x, y, z) F1(z, x, y) 131 #define F3(x, y, z) (x ^ y ^ z) 132 #define F4(x, y, z) (y ^ (x | ~z)) 133 134 // This is the central step in the MD5 algorithm. 135 #define MD5STEP(f, w, x, y, z, data, s) \ 136 (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x) 137 138 // The core of the MD5 algorithm, this alters an existing MD5 hash to 139 // reflect the addition of 16 longwords of new data. MD5Update blocks 140 // the data and converts bytes into longwords for this routine. 141 void MD5Transform(uint32 buf[4], const uint32 in[16]) { 142 uint32 a = buf[0]; 143 uint32 b = buf[1]; 144 uint32 c = buf[2]; 145 uint32 d = buf[3]; 146 147 MD5STEP(F1, a, b, c, d, in[ 0] + 0xd76aa478, 7); 148 MD5STEP(F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12); 149 MD5STEP(F1, c, d, a, b, in[ 2] + 0x242070db, 17); 150 MD5STEP(F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22); 151 MD5STEP(F1, a, b, c, d, in[ 4] + 0xf57c0faf, 7); 152 MD5STEP(F1, d, a, b, c, in[ 5] + 0x4787c62a, 12); 153 MD5STEP(F1, c, d, a, b, in[ 6] + 0xa8304613, 17); 154 MD5STEP(F1, b, c, d, a, in[ 7] + 0xfd469501, 22); 155 MD5STEP(F1, a, b, c, d, in[ 8] + 0x698098d8, 7); 156 MD5STEP(F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12); 157 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); 158 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); 159 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); 160 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); 161 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); 162 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); 163 164 MD5STEP(F2, a, b, c, d, in[ 1] + 0xf61e2562, 5); 165 MD5STEP(F2, d, a, b, c, in[ 6] + 0xc040b340, 9); 166 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); 167 MD5STEP(F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20); 168 MD5STEP(F2, a, b, c, d, in[ 5] + 0xd62f105d, 5); 169 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); 170 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); 171 MD5STEP(F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20); 172 MD5STEP(F2, a, b, c, d, in[ 9] + 0x21e1cde6, 5); 173 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); 174 MD5STEP(F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14); 175 MD5STEP(F2, b, c, d, a, in[ 8] + 0x455a14ed, 20); 176 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); 177 MD5STEP(F2, d, a, b, c, in[ 2] + 0xfcefa3f8, 9); 178 MD5STEP(F2, c, d, a, b, in[ 7] + 0x676f02d9, 14); 179 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); 180 181 MD5STEP(F3, a, b, c, d, in[ 5] + 0xfffa3942, 4); 182 MD5STEP(F3, d, a, b, c, in[ 8] + 0x8771f681, 11); 183 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); 184 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); 185 MD5STEP(F3, a, b, c, d, in[ 1] + 0xa4beea44, 4); 186 MD5STEP(F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11); 187 MD5STEP(F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16); 188 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); 189 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); 190 MD5STEP(F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11); 191 MD5STEP(F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16); 192 MD5STEP(F3, b, c, d, a, in[ 6] + 0x04881d05, 23); 193 MD5STEP(F3, a, b, c, d, in[ 9] + 0xd9d4d039, 4); 194 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); 195 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); 196 MD5STEP(F3, b, c, d, a, in[ 2] + 0xc4ac5665, 23); 197 198 MD5STEP(F4, a, b, c, d, in[ 0] + 0xf4292244, 6); 199 MD5STEP(F4, d, a, b, c, in[ 7] + 0x432aff97, 10); 200 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); 201 MD5STEP(F4, b, c, d, a, in[ 5] + 0xfc93a039, 21); 202 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); 203 MD5STEP(F4, d, a, b, c, in[ 3] + 0x8f0ccc92, 10); 204 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); 205 MD5STEP(F4, b, c, d, a, in[ 1] + 0x85845dd1, 21); 206 MD5STEP(F4, a, b, c, d, in[ 8] + 0x6fa87e4f, 6); 207 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); 208 MD5STEP(F4, c, d, a, b, in[ 6] + 0xa3014314, 15); 209 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); 210 MD5STEP(F4, a, b, c, d, in[ 4] + 0xf7537e82, 6); 211 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); 212 MD5STEP(F4, c, d, a, b, in[ 2] + 0x2ad7d2bb, 15); 213 MD5STEP(F4, b, c, d, a, in[ 9] + 0xeb86d391, 21); 214 buf[0] += a; 215 buf[1] += b; 216 buf[2] += c; 217 buf[3] += d; 218 } 219