1 /* 2 * Copyright 2012 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 * 7 * The following code is based on the description in RFC 1321. 8 * http://www.ietf.org/rfc/rfc1321.txt 9 */ 10 11 //The following macros can be defined to affect the MD5 code generated. 12 //SK_MD5_CLEAR_DATA causes all intermediate state to be overwritten with 0's. 13 //SK_CPU_LENDIAN allows 32 bit <=> 8 bit conversions without copies (if alligned). 14 //SK_CPU_FAST_UNALIGNED_ACCESS allows 32 bit <=> 8 bit conversions without copies if SK_CPU_LENDIAN. 15 16 #include "SkMD5.h" 17 #include <string.h> 18 19 /** MD5 basic transformation. Transforms state based on block. */ 20 static void transform(uint32_t state[4], const uint8_t block[64]); 21 22 /** Encodes input into output (4 little endian 32 bit values). */ 23 static void encode(uint8_t output[16], const uint32_t input[4]); 24 25 /** Encodes input into output (little endian 64 bit value). */ 26 static void encode(uint8_t output[8], const uint64_t input); 27 28 /** Decodes input (4 little endian 32 bit values) into storage, if required. */ 29 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]); 30 31 SkMD5::SkMD5() : byteCount(0) { 32 // These are magic numbers from the specification. 33 this->state[0] = 0x67452301; 34 this->state[1] = 0xefcdab89; 35 this->state[2] = 0x98badcfe; 36 this->state[3] = 0x10325476; 37 } 38 39 bool SkMD5::write(const void* buf, size_t inputLength) { 40 const uint8_t* input = reinterpret_cast<const uint8_t*>(buf); 41 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F); 42 unsigned int bufferAvailable = 64 - bufferIndex; 43 44 unsigned int inputIndex; 45 if (inputLength >= bufferAvailable) { 46 if (bufferIndex) { 47 memcpy(&this->buffer[bufferIndex], input, bufferAvailable); 48 transform(this->state, this->buffer); 49 inputIndex = bufferAvailable; 50 } else { 51 inputIndex = 0; 52 } 53 54 for (; inputIndex + 63 < inputLength; inputIndex += 64) { 55 transform(this->state, &input[inputIndex]); 56 } 57 58 bufferIndex = 0; 59 } else { 60 inputIndex = 0; 61 } 62 63 memcpy(&this->buffer[bufferIndex], &input[inputIndex], inputLength - inputIndex); 64 65 this->byteCount += inputLength; 66 return true; 67 } 68 69 void SkMD5::finish(Digest& digest) { 70 // Get the number of bits before padding. 71 uint8_t bits[8]; 72 encode(bits, this->byteCount << 3); 73 74 // Pad out to 56 mod 64. 75 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F); 76 unsigned int paddingLength = (bufferIndex < 56) ? (56 - bufferIndex) : (120 - bufferIndex); 77 static uint8_t PADDING[64] = { 78 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 79 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 80 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 81 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 82 }; 83 (void)this->write(PADDING, paddingLength); 84 85 // Append length (length before padding, will cause final update). 86 (void)this->write(bits, 8); 87 88 // Write out digest. 89 encode(digest.data, this->state); 90 91 #if defined(SK_MD5_CLEAR_DATA) 92 // Clear state. 93 memset(this, 0, sizeof(*this)); 94 #endif 95 } 96 97 struct F { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 98 //return (x & y) | ((~x) & z); 99 return ((y ^ z) & x) ^ z; //equivelent but faster 100 }}; 101 102 struct G { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 103 return (x & z) | (y & (~z)); 104 //return ((x ^ y) & z) ^ y; //equivelent but slower 105 }}; 106 107 struct H { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 108 return x ^ y ^ z; 109 }}; 110 111 struct I { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 112 return y ^ (x | (~z)); 113 }}; 114 115 /** Rotates x left n bits. */ 116 static inline uint32_t rotate_left(uint32_t x, uint8_t n) { 117 return (x << n) | (x >> (32 - n)); 118 } 119 120 template <typename T> 121 static inline void operation(T operation, uint32_t& a, uint32_t b, uint32_t c, uint32_t d, 122 uint32_t x, uint8_t s, uint32_t t) { 123 a = b + rotate_left(a + operation(b, c, d) + x + t, s); 124 } 125 126 static void transform(uint32_t state[4], const uint8_t block[64]) { 127 uint32_t a = state[0], b = state[1], c = state[2], d = state[3]; 128 129 uint32_t storage[16]; 130 const uint32_t* X = decode(storage, block); 131 132 // Round 1 133 operation(F(), a, b, c, d, X[ 0], 7, 0xd76aa478); // 1 134 operation(F(), d, a, b, c, X[ 1], 12, 0xe8c7b756); // 2 135 operation(F(), c, d, a, b, X[ 2], 17, 0x242070db); // 3 136 operation(F(), b, c, d, a, X[ 3], 22, 0xc1bdceee); // 4 137 operation(F(), a, b, c, d, X[ 4], 7, 0xf57c0faf); // 5 138 operation(F(), d, a, b, c, X[ 5], 12, 0x4787c62a); // 6 139 operation(F(), c, d, a, b, X[ 6], 17, 0xa8304613); // 7 140 operation(F(), b, c, d, a, X[ 7], 22, 0xfd469501); // 8 141 operation(F(), a, b, c, d, X[ 8], 7, 0x698098d8); // 9 142 operation(F(), d, a, b, c, X[ 9], 12, 0x8b44f7af); // 10 143 operation(F(), c, d, a, b, X[10], 17, 0xffff5bb1); // 11 144 operation(F(), b, c, d, a, X[11], 22, 0x895cd7be); // 12 145 operation(F(), a, b, c, d, X[12], 7, 0x6b901122); // 13 146 operation(F(), d, a, b, c, X[13], 12, 0xfd987193); // 14 147 operation(F(), c, d, a, b, X[14], 17, 0xa679438e); // 15 148 operation(F(), b, c, d, a, X[15], 22, 0x49b40821); // 16 149 150 // Round 2 151 operation(G(), a, b, c, d, X[ 1], 5, 0xf61e2562); // 17 152 operation(G(), d, a, b, c, X[ 6], 9, 0xc040b340); // 18 153 operation(G(), c, d, a, b, X[11], 14, 0x265e5a51); // 19 154 operation(G(), b, c, d, a, X[ 0], 20, 0xe9b6c7aa); // 20 155 operation(G(), a, b, c, d, X[ 5], 5, 0xd62f105d); // 21 156 operation(G(), d, a, b, c, X[10], 9, 0x2441453); // 22 157 operation(G(), c, d, a, b, X[15], 14, 0xd8a1e681); // 23 158 operation(G(), b, c, d, a, X[ 4], 20, 0xe7d3fbc8); // 24 159 operation(G(), a, b, c, d, X[ 9], 5, 0x21e1cde6); // 25 160 operation(G(), d, a, b, c, X[14], 9, 0xc33707d6); // 26 161 operation(G(), c, d, a, b, X[ 3], 14, 0xf4d50d87); // 27 162 operation(G(), b, c, d, a, X[ 8], 20, 0x455a14ed); // 28 163 operation(G(), a, b, c, d, X[13], 5, 0xa9e3e905); // 29 164 operation(G(), d, a, b, c, X[ 2], 9, 0xfcefa3f8); // 30 165 operation(G(), c, d, a, b, X[ 7], 14, 0x676f02d9); // 31 166 operation(G(), b, c, d, a, X[12], 20, 0x8d2a4c8a); // 32 167 168 // Round 3 169 operation(H(), a, b, c, d, X[ 5], 4, 0xfffa3942); // 33 170 operation(H(), d, a, b, c, X[ 8], 11, 0x8771f681); // 34 171 operation(H(), c, d, a, b, X[11], 16, 0x6d9d6122); // 35 172 operation(H(), b, c, d, a, X[14], 23, 0xfde5380c); // 36 173 operation(H(), a, b, c, d, X[ 1], 4, 0xa4beea44); // 37 174 operation(H(), d, a, b, c, X[ 4], 11, 0x4bdecfa9); // 38 175 operation(H(), c, d, a, b, X[ 7], 16, 0xf6bb4b60); // 39 176 operation(H(), b, c, d, a, X[10], 23, 0xbebfbc70); // 40 177 operation(H(), a, b, c, d, X[13], 4, 0x289b7ec6); // 41 178 operation(H(), d, a, b, c, X[ 0], 11, 0xeaa127fa); // 42 179 operation(H(), c, d, a, b, X[ 3], 16, 0xd4ef3085); // 43 180 operation(H(), b, c, d, a, X[ 6], 23, 0x4881d05); // 44 181 operation(H(), a, b, c, d, X[ 9], 4, 0xd9d4d039); // 45 182 operation(H(), d, a, b, c, X[12], 11, 0xe6db99e5); // 46 183 operation(H(), c, d, a, b, X[15], 16, 0x1fa27cf8); // 47 184 operation(H(), b, c, d, a, X[ 2], 23, 0xc4ac5665); // 48 185 186 // Round 4 187 operation(I(), a, b, c, d, X[ 0], 6, 0xf4292244); // 49 188 operation(I(), d, a, b, c, X[ 7], 10, 0x432aff97); // 50 189 operation(I(), c, d, a, b, X[14], 15, 0xab9423a7); // 51 190 operation(I(), b, c, d, a, X[ 5], 21, 0xfc93a039); // 52 191 operation(I(), a, b, c, d, X[12], 6, 0x655b59c3); // 53 192 operation(I(), d, a, b, c, X[ 3], 10, 0x8f0ccc92); // 54 193 operation(I(), c, d, a, b, X[10], 15, 0xffeff47d); // 55 194 operation(I(), b, c, d, a, X[ 1], 21, 0x85845dd1); // 56 195 operation(I(), a, b, c, d, X[ 8], 6, 0x6fa87e4f); // 57 196 operation(I(), d, a, b, c, X[15], 10, 0xfe2ce6e0); // 58 197 operation(I(), c, d, a, b, X[ 6], 15, 0xa3014314); // 59 198 operation(I(), b, c, d, a, X[13], 21, 0x4e0811a1); // 60 199 operation(I(), a, b, c, d, X[ 4], 6, 0xf7537e82); // 61 200 operation(I(), d, a, b, c, X[11], 10, 0xbd3af235); // 62 201 operation(I(), c, d, a, b, X[ 2], 15, 0x2ad7d2bb); // 63 202 operation(I(), b, c, d, a, X[ 9], 21, 0xeb86d391); // 64 203 204 state[0] += a; 205 state[1] += b; 206 state[2] += c; 207 state[3] += d; 208 209 #if defined(SK_MD5_CLEAR_DATA) 210 // Clear sensitive information. 211 if (X == &storage) { 212 memset(storage, 0, sizeof(storage)); 213 } 214 #endif 215 } 216 217 static void encode(uint8_t output[16], const uint32_t input[4]) { 218 for (size_t i = 0, j = 0; i < 4; i++, j += 4) { 219 output[j ] = (uint8_t) (input[i] & 0xff); 220 output[j+1] = (uint8_t)((input[i] >> 8) & 0xff); 221 output[j+2] = (uint8_t)((input[i] >> 16) & 0xff); 222 output[j+3] = (uint8_t)((input[i] >> 24) & 0xff); 223 } 224 } 225 226 static void encode(uint8_t output[8], const uint64_t input) { 227 output[0] = (uint8_t) (input & 0xff); 228 output[1] = (uint8_t)((input >> 8) & 0xff); 229 output[2] = (uint8_t)((input >> 16) & 0xff); 230 output[3] = (uint8_t)((input >> 24) & 0xff); 231 output[4] = (uint8_t)((input >> 32) & 0xff); 232 output[5] = (uint8_t)((input >> 40) & 0xff); 233 output[6] = (uint8_t)((input >> 48) & 0xff); 234 output[7] = (uint8_t)((input >> 56) & 0xff); 235 } 236 237 static inline bool is_aligned(const void *pointer, size_t byte_count) { 238 return reinterpret_cast<uintptr_t>(pointer) % byte_count == 0; 239 } 240 241 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]) { 242 #if defined(SK_CPU_LENDIAN) && defined(SK_CPU_FAST_UNALIGNED_ACCESS) 243 return reinterpret_cast<const uint32_t*>(input); 244 #else 245 #if defined(SK_CPU_LENDIAN) 246 if (is_aligned(input, 4)) { 247 return reinterpret_cast<const uint32_t*>(input); 248 } 249 #endif 250 for (size_t i = 0, j = 0; j < 64; i++, j += 4) { 251 storage[i] = ((uint32_t)input[j ]) | 252 (((uint32_t)input[j+1]) << 8) | 253 (((uint32_t)input[j+2]) << 16) | 254 (((uint32_t)input[j+3]) << 24); 255 } 256 return storage; 257 #endif 258 } 259
