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 #include "SkTypes.h" 12 #include "SkMD5.h" 13 #include <string.h> 14 15 /** MD5 basic transformation. Transforms state based on block. */ 16 static void transform(uint32_t state[4], const uint8_t block[64]); 17 18 /** Encodes input into output (4 little endian 32 bit values). */ 19 static void encode(uint8_t output[16], const uint32_t input[4]); 20 21 /** Encodes input into output (little endian 64 bit value). */ 22 static void encode(uint8_t output[8], const uint64_t input); 23 24 /** Decodes input (4 little endian 32 bit values) into storage, if required. */ 25 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]); 26 27 SkMD5::SkMD5() : byteCount(0) { 28 // These are magic numbers from the specification. 29 this->state[0] = 0x67452301; 30 this->state[1] = 0xefcdab89; 31 this->state[2] = 0x98badcfe; 32 this->state[3] = 0x10325476; 33 } 34 35 void SkMD5::update(const uint8_t* input, size_t inputLength) { 36 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F); 37 unsigned int bufferAvailable = 64 - bufferIndex; 38 39 unsigned int inputIndex; 40 if (inputLength >= bufferAvailable) { 41 if (bufferIndex) { 42 memcpy(&this->buffer[bufferIndex], input, bufferAvailable); 43 transform(this->state, this->buffer); 44 inputIndex = bufferAvailable; 45 } else { 46 inputIndex = 0; 47 } 48 49 for (; inputIndex + 63 < inputLength; inputIndex += 64) { 50 transform(this->state, &input[inputIndex]); 51 } 52 53 bufferIndex = 0; 54 } else { 55 inputIndex = 0; 56 } 57 58 memcpy(&this->buffer[bufferIndex], &input[inputIndex], inputLength - inputIndex); 59 60 this->byteCount += inputLength; 61 } 62 63 void SkMD5::finish(Digest& digest) { 64 // Get the number of bits before padding. 65 uint8_t bits[8]; 66 encode(bits, this->byteCount << 3); 67 68 // Pad out to 56 mod 64. 69 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F); 70 unsigned int paddingLength = (bufferIndex < 56) ? (56 - bufferIndex) : (120 - bufferIndex); 71 static uint8_t PADDING[64] = { 72 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 73 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 74 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 75 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 76 }; 77 this->update(PADDING, paddingLength); 78 79 // Append length (length before padding, will cause final update). 80 this->update(bits, 8); 81 82 // Write out digest. 83 encode(digest.data, this->state); 84 85 #if defined(SK_MD5_CLEAR_DATA) 86 // Clear state. 87 memset(this, 0, sizeof(*this)); 88 #endif 89 } 90 91 struct F { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 92 //return (x & y) | ((~x) & z); 93 return ((y ^ z) & x) ^ z; //equivelent but faster 94 }}; 95 96 struct G { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 97 return (x & z) | (y & (~z)); 98 //return ((x ^ y) & z) ^ y; //equivelent but slower 99 }}; 100 101 struct H { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 102 return x ^ y ^ z; 103 }}; 104 105 struct I { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) { 106 return y ^ (x | (~z)); 107 }}; 108 109 /** Rotates x left n bits. */ 110 static inline uint32_t rotate_left(uint32_t x, uint8_t n) { 111 return (x << n) | (x >> (32 - n)); 112 } 113 114 template <typename T> 115 static inline void operation(T operation, uint32_t& a, uint32_t b, uint32_t c, uint32_t d, 116 uint32_t x, uint8_t s, uint32_t t) { 117 a = b + rotate_left(a + operation(b, c, d) + x + t, s); 118 } 119 120 static void transform(uint32_t state[4], const uint8_t block[64]) { 121 uint32_t a = state[0], b = state[1], c = state[2], d = state[3]; 122 123 uint32_t storage[16]; 124 const uint32_t* X = decode(storage, block); 125 126 // Round 1 127 operation(F(), a, b, c, d, X[ 0], 7, 0xd76aa478); // 1 128 operation(F(), d, a, b, c, X[ 1], 12, 0xe8c7b756); // 2 129 operation(F(), c, d, a, b, X[ 2], 17, 0x242070db); // 3 130 operation(F(), b, c, d, a, X[ 3], 22, 0xc1bdceee); // 4 131 operation(F(), a, b, c, d, X[ 4], 7, 0xf57c0faf); // 5 132 operation(F(), d, a, b, c, X[ 5], 12, 0x4787c62a); // 6 133 operation(F(), c, d, a, b, X[ 6], 17, 0xa8304613); // 7 134 operation(F(), b, c, d, a, X[ 7], 22, 0xfd469501); // 8 135 operation(F(), a, b, c, d, X[ 8], 7, 0x698098d8); // 9 136 operation(F(), d, a, b, c, X[ 9], 12, 0x8b44f7af); // 10 137 operation(F(), c, d, a, b, X[10], 17, 0xffff5bb1); // 11 138 operation(F(), b, c, d, a, X[11], 22, 0x895cd7be); // 12 139 operation(F(), a, b, c, d, X[12], 7, 0x6b901122); // 13 140 operation(F(), d, a, b, c, X[13], 12, 0xfd987193); // 14 141 operation(F(), c, d, a, b, X[14], 17, 0xa679438e); // 15 142 operation(F(), b, c, d, a, X[15], 22, 0x49b40821); // 16 143 144 // Round 2 145 operation(G(), a, b, c, d, X[ 1], 5, 0xf61e2562); // 17 146 operation(G(), d, a, b, c, X[ 6], 9, 0xc040b340); // 18 147 operation(G(), c, d, a, b, X[11], 14, 0x265e5a51); // 19 148 operation(G(), b, c, d, a, X[ 0], 20, 0xe9b6c7aa); // 20 149 operation(G(), a, b, c, d, X[ 5], 5, 0xd62f105d); // 21 150 operation(G(), d, a, b, c, X[10], 9, 0x2441453); // 22 151 operation(G(), c, d, a, b, X[15], 14, 0xd8a1e681); // 23 152 operation(G(), b, c, d, a, X[ 4], 20, 0xe7d3fbc8); // 24 153 operation(G(), a, b, c, d, X[ 9], 5, 0x21e1cde6); // 25 154 operation(G(), d, a, b, c, X[14], 9, 0xc33707d6); // 26 155 operation(G(), c, d, a, b, X[ 3], 14, 0xf4d50d87); // 27 156 operation(G(), b, c, d, a, X[ 8], 20, 0x455a14ed); // 28 157 operation(G(), a, b, c, d, X[13], 5, 0xa9e3e905); // 29 158 operation(G(), d, a, b, c, X[ 2], 9, 0xfcefa3f8); // 30 159 operation(G(), c, d, a, b, X[ 7], 14, 0x676f02d9); // 31 160 operation(G(), b, c, d, a, X[12], 20, 0x8d2a4c8a); // 32 161 162 // Round 3 163 operation(H(), a, b, c, d, X[ 5], 4, 0xfffa3942); // 33 164 operation(H(), d, a, b, c, X[ 8], 11, 0x8771f681); // 34 165 operation(H(), c, d, a, b, X[11], 16, 0x6d9d6122); // 35 166 operation(H(), b, c, d, a, X[14], 23, 0xfde5380c); // 36 167 operation(H(), a, b, c, d, X[ 1], 4, 0xa4beea44); // 37 168 operation(H(), d, a, b, c, X[ 4], 11, 0x4bdecfa9); // 38 169 operation(H(), c, d, a, b, X[ 7], 16, 0xf6bb4b60); // 39 170 operation(H(), b, c, d, a, X[10], 23, 0xbebfbc70); // 40 171 operation(H(), a, b, c, d, X[13], 4, 0x289b7ec6); // 41 172 operation(H(), d, a, b, c, X[ 0], 11, 0xeaa127fa); // 42 173 operation(H(), c, d, a, b, X[ 3], 16, 0xd4ef3085); // 43 174 operation(H(), b, c, d, a, X[ 6], 23, 0x4881d05); // 44 175 operation(H(), a, b, c, d, X[ 9], 4, 0xd9d4d039); // 45 176 operation(H(), d, a, b, c, X[12], 11, 0xe6db99e5); // 46 177 operation(H(), c, d, a, b, X[15], 16, 0x1fa27cf8); // 47 178 operation(H(), b, c, d, a, X[ 2], 23, 0xc4ac5665); // 48 179 180 // Round 4 181 operation(I(), a, b, c, d, X[ 0], 6, 0xf4292244); // 49 182 operation(I(), d, a, b, c, X[ 7], 10, 0x432aff97); // 50 183 operation(I(), c, d, a, b, X[14], 15, 0xab9423a7); // 51 184 operation(I(), b, c, d, a, X[ 5], 21, 0xfc93a039); // 52 185 operation(I(), a, b, c, d, X[12], 6, 0x655b59c3); // 53 186 operation(I(), d, a, b, c, X[ 3], 10, 0x8f0ccc92); // 54 187 operation(I(), c, d, a, b, X[10], 15, 0xffeff47d); // 55 188 operation(I(), b, c, d, a, X[ 1], 21, 0x85845dd1); // 56 189 operation(I(), a, b, c, d, X[ 8], 6, 0x6fa87e4f); // 57 190 operation(I(), d, a, b, c, X[15], 10, 0xfe2ce6e0); // 58 191 operation(I(), c, d, a, b, X[ 6], 15, 0xa3014314); // 59 192 operation(I(), b, c, d, a, X[13], 21, 0x4e0811a1); // 60 193 operation(I(), a, b, c, d, X[ 4], 6, 0xf7537e82); // 61 194 operation(I(), d, a, b, c, X[11], 10, 0xbd3af235); // 62 195 operation(I(), c, d, a, b, X[ 2], 15, 0x2ad7d2bb); // 63 196 operation(I(), b, c, d, a, X[ 9], 21, 0xeb86d391); // 64 197 198 state[0] += a; 199 state[1] += b; 200 state[2] += c; 201 state[3] += d; 202 203 #if defined(SK_MD5_CLEAR_DATA) 204 // Clear sensitive information. 205 if (X == &storage) { 206 memset(storage, 0, sizeof(storage)); 207 } 208 #endif 209 } 210 211 static void encode(uint8_t output[16], const uint32_t input[4]) { 212 for (size_t i = 0, j = 0; i < 4; i++, j += 4) { 213 output[j ] = (uint8_t) (input[i] & 0xff); 214 output[j+1] = (uint8_t)((input[i] >> 8) & 0xff); 215 output[j+2] = (uint8_t)((input[i] >> 16) & 0xff); 216 output[j+3] = (uint8_t)((input[i] >> 24) & 0xff); 217 } 218 } 219 220 static void encode(uint8_t output[8], const uint64_t input) { 221 output[0] = (uint8_t) (input & 0xff); 222 output[1] = (uint8_t)((input >> 8) & 0xff); 223 output[2] = (uint8_t)((input >> 16) & 0xff); 224 output[3] = (uint8_t)((input >> 24) & 0xff); 225 output[4] = (uint8_t)((input >> 32) & 0xff); 226 output[5] = (uint8_t)((input >> 40) & 0xff); 227 output[6] = (uint8_t)((input >> 48) & 0xff); 228 output[7] = (uint8_t)((input >> 56) & 0xff); 229 } 230 231 static inline bool is_aligned(const void *pointer, size_t byte_count) { 232 return reinterpret_cast<uintptr_t>(pointer) % byte_count == 0; 233 } 234 235 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]) { 236 #if defined(SK_CPU_LENDIAN) && defined(SK_CPU_FAST_UNALIGNED_ACCESS) 237 return reinterpret_cast<const uint32_t*>(input); 238 #else 239 #if defined(SK_CPU_LENDIAN) 240 if (is_aligned(input, 4)) { 241 return reinterpret_cast<const uint32_t*>(input); 242 } 243 #endif 244 for (size_t i = 0, j = 0; j < 64; i++, j += 4) { 245 storage[i] = ((uint32_t)input[j ]) | 246 (((uint32_t)input[j+1]) << 8) | 247 (((uint32_t)input[j+2]) << 16) | 248 (((uint32_t)input[j+3]) << 24); 249 } 250 return storage; 251 #endif 252 } 253
