henrike@webrtc.org | f7795df | 2014-05-13 18:00:26 +0000 | [diff] [blame^] | 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 "webrtc/base/md5.h" |
| 22 | |
| 23 | // TODO: Avoid memcmpy - hash directly from memory. |
| 24 | #include <string.h> // for memcpy(). |
| 25 | |
| 26 | #include "webrtc/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] = rtc::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 | } |