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 "src/base/SkUtils.h"
17 #include "src/core/SkMD5.h"
18
19 #include "include/private/base/SkFeatures.h"
20 #include "include/private/base/SkMalloc.h"
21
22 /** MD5 basic transformation. Transforms state based on block. */
23 static void transform(uint32_t state[4], const uint8_t block[64]);
24
25 /** Encodes input into output (4 little endian 32 bit values). */
26 static void encode(uint8_t output[16], const uint32_t input[4]);
27
28 /** Encodes input into output (little endian 64 bit value). */
29 static void encode(uint8_t output[8], const uint64_t input);
30
31 /** Decodes input (4 little endian 32 bit values) into storage, if required. */
32 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]);
33
SkMD5()34 SkMD5::SkMD5() : byteCount(0) {
35 // These are magic numbers from the specification.
36 this->state[0] = 0x67452301;
37 this->state[1] = 0xefcdab89;
38 this->state[2] = 0x98badcfe;
39 this->state[3] = 0x10325476;
40 }
41
write(const void * buf,size_t inputLength)42 bool SkMD5::write(const void* buf, size_t inputLength) {
43 const uint8_t* input = reinterpret_cast<const uint8_t*>(buf);
44 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
45 unsigned int bufferAvailable = 64 - bufferIndex;
46
47 unsigned int inputIndex;
48 if (inputLength >= bufferAvailable) {
49 if (bufferIndex) {
50 sk_careful_memcpy(&this->buffer[bufferIndex], input, bufferAvailable);
51 transform(this->state, this->buffer);
52 inputIndex = bufferAvailable;
53 } else {
54 inputIndex = 0;
55 }
56
57 for (; inputIndex + 63 < inputLength; inputIndex += 64) {
58 transform(this->state, &input[inputIndex]);
59 }
60
61 bufferIndex = 0;
62 } else {
63 inputIndex = 0;
64 }
65
66 sk_careful_memcpy(&this->buffer[bufferIndex], &input[inputIndex], inputLength - inputIndex);
67
68 this->byteCount += inputLength;
69 return true;
70 }
71
finish()72 SkMD5::Digest SkMD5::finish() {
73 SkMD5::Digest digest;
74 // Get the number of bits before padding.
75 uint8_t bits[8];
76 encode(bits, this->byteCount << 3);
77
78 // Pad out to 56 mod 64.
79 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
80 unsigned int paddingLength = (bufferIndex < 56) ? (56 - bufferIndex) : (120 - bufferIndex);
81 static const uint8_t PADDING[64] = {
82 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
83 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
84 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
85 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
86 };
87 (void)this->write(PADDING, paddingLength);
88
89 // Append length (length before padding, will cause final update).
90 (void)this->write(bits, 8);
91
92 // Write out digest.
93 encode(digest.data, this->state);
94
95 #if defined(SK_MD5_CLEAR_DATA)
96 // Clear state.
97 memset(this, 0, sizeof(*this));
98 #endif
99 return digest;
100 }
101
to_hex_string(const uint8_t * data,const char * hexDigits)102 static SkString to_hex_string(const uint8_t* data, const char* hexDigits) {
103 SkString hexString(2 * sizeof(SkMD5::Digest::data));
104 for (size_t i = 0; i < sizeof(SkMD5::Digest::data); ++i) {
105 uint8_t byte = data[i];
106 hexString[2 * i + 0] = hexDigits[byte >> 4];
107 hexString[2 * i + 1] = hexDigits[byte & 0xF];
108 }
109 return hexString;
110 }
111
toHexString() const112 SkString SkMD5::Digest::toHexString() const {
113 return to_hex_string(data, SkHexadecimalDigits::gUpper);
114 }
115
toLowercaseHexString() const116 SkString SkMD5::Digest::toLowercaseHexString() const {
117 return to_hex_string(data, SkHexadecimalDigits::gLower);
118 }
119
operator ()F120 struct F { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
121 //return (x & y) | ((~x) & z);
122 return ((y ^ z) & x) ^ z; //equivelent but faster
123 }};
124
operator ()G125 struct G { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
126 return (x & z) | (y & (~z));
127 //return ((x ^ y) & z) ^ y; //equivelent but slower
128 }};
129
operator ()H130 struct H { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
131 return x ^ y ^ z;
132 }};
133
operator ()I134 struct I { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
135 return y ^ (x | (~z));
136 }};
137
138 /** Rotates x left n bits. */
rotate_left(uint32_t x,uint8_t n)139 static inline uint32_t rotate_left(uint32_t x, uint8_t n) {
140 return (x << n) | (x >> (32 - n));
141 }
142
143 template <typename T>
operation(T operation,uint32_t & a,uint32_t b,uint32_t c,uint32_t d,uint32_t x,uint8_t s,uint32_t t)144 static inline void operation(T operation, uint32_t& a, uint32_t b, uint32_t c, uint32_t d,
145 uint32_t x, uint8_t s, uint32_t t) {
146 a = b + rotate_left(a + operation(b, c, d) + x + t, s);
147 }
148
transform(uint32_t state[4],const uint8_t block[64])149 static void transform(uint32_t state[4], const uint8_t block[64]) {
150 uint32_t a = state[0], b = state[1], c = state[2], d = state[3];
151
152 uint32_t storage[16];
153 const uint32_t* X = decode(storage, block);
154
155 // Round 1
156 operation(F(), a, b, c, d, X[ 0], 7, 0xd76aa478); // 1
157 operation(F(), d, a, b, c, X[ 1], 12, 0xe8c7b756); // 2
158 operation(F(), c, d, a, b, X[ 2], 17, 0x242070db); // 3
159 operation(F(), b, c, d, a, X[ 3], 22, 0xc1bdceee); // 4
160 operation(F(), a, b, c, d, X[ 4], 7, 0xf57c0faf); // 5
161 operation(F(), d, a, b, c, X[ 5], 12, 0x4787c62a); // 6
162 operation(F(), c, d, a, b, X[ 6], 17, 0xa8304613); // 7
163 operation(F(), b, c, d, a, X[ 7], 22, 0xfd469501); // 8
164 operation(F(), a, b, c, d, X[ 8], 7, 0x698098d8); // 9
165 operation(F(), d, a, b, c, X[ 9], 12, 0x8b44f7af); // 10
166 operation(F(), c, d, a, b, X[10], 17, 0xffff5bb1); // 11
167 operation(F(), b, c, d, a, X[11], 22, 0x895cd7be); // 12
168 operation(F(), a, b, c, d, X[12], 7, 0x6b901122); // 13
169 operation(F(), d, a, b, c, X[13], 12, 0xfd987193); // 14
170 operation(F(), c, d, a, b, X[14], 17, 0xa679438e); // 15
171 operation(F(), b, c, d, a, X[15], 22, 0x49b40821); // 16
172
173 // Round 2
174 operation(G(), a, b, c, d, X[ 1], 5, 0xf61e2562); // 17
175 operation(G(), d, a, b, c, X[ 6], 9, 0xc040b340); // 18
176 operation(G(), c, d, a, b, X[11], 14, 0x265e5a51); // 19
177 operation(G(), b, c, d, a, X[ 0], 20, 0xe9b6c7aa); // 20
178 operation(G(), a, b, c, d, X[ 5], 5, 0xd62f105d); // 21
179 operation(G(), d, a, b, c, X[10], 9, 0x2441453); // 22
180 operation(G(), c, d, a, b, X[15], 14, 0xd8a1e681); // 23
181 operation(G(), b, c, d, a, X[ 4], 20, 0xe7d3fbc8); // 24
182 operation(G(), a, b, c, d, X[ 9], 5, 0x21e1cde6); // 25
183 operation(G(), d, a, b, c, X[14], 9, 0xc33707d6); // 26
184 operation(G(), c, d, a, b, X[ 3], 14, 0xf4d50d87); // 27
185 operation(G(), b, c, d, a, X[ 8], 20, 0x455a14ed); // 28
186 operation(G(), a, b, c, d, X[13], 5, 0xa9e3e905); // 29
187 operation(G(), d, a, b, c, X[ 2], 9, 0xfcefa3f8); // 30
188 operation(G(), c, d, a, b, X[ 7], 14, 0x676f02d9); // 31
189 operation(G(), b, c, d, a, X[12], 20, 0x8d2a4c8a); // 32
190
191 // Round 3
192 operation(H(), a, b, c, d, X[ 5], 4, 0xfffa3942); // 33
193 operation(H(), d, a, b, c, X[ 8], 11, 0x8771f681); // 34
194 operation(H(), c, d, a, b, X[11], 16, 0x6d9d6122); // 35
195 operation(H(), b, c, d, a, X[14], 23, 0xfde5380c); // 36
196 operation(H(), a, b, c, d, X[ 1], 4, 0xa4beea44); // 37
197 operation(H(), d, a, b, c, X[ 4], 11, 0x4bdecfa9); // 38
198 operation(H(), c, d, a, b, X[ 7], 16, 0xf6bb4b60); // 39
199 operation(H(), b, c, d, a, X[10], 23, 0xbebfbc70); // 40
200 operation(H(), a, b, c, d, X[13], 4, 0x289b7ec6); // 41
201 operation(H(), d, a, b, c, X[ 0], 11, 0xeaa127fa); // 42
202 operation(H(), c, d, a, b, X[ 3], 16, 0xd4ef3085); // 43
203 operation(H(), b, c, d, a, X[ 6], 23, 0x4881d05); // 44
204 operation(H(), a, b, c, d, X[ 9], 4, 0xd9d4d039); // 45
205 operation(H(), d, a, b, c, X[12], 11, 0xe6db99e5); // 46
206 operation(H(), c, d, a, b, X[15], 16, 0x1fa27cf8); // 47
207 operation(H(), b, c, d, a, X[ 2], 23, 0xc4ac5665); // 48
208
209 // Round 4
210 operation(I(), a, b, c, d, X[ 0], 6, 0xf4292244); // 49
211 operation(I(), d, a, b, c, X[ 7], 10, 0x432aff97); // 50
212 operation(I(), c, d, a, b, X[14], 15, 0xab9423a7); // 51
213 operation(I(), b, c, d, a, X[ 5], 21, 0xfc93a039); // 52
214 operation(I(), a, b, c, d, X[12], 6, 0x655b59c3); // 53
215 operation(I(), d, a, b, c, X[ 3], 10, 0x8f0ccc92); // 54
216 operation(I(), c, d, a, b, X[10], 15, 0xffeff47d); // 55
217 operation(I(), b, c, d, a, X[ 1], 21, 0x85845dd1); // 56
218 operation(I(), a, b, c, d, X[ 8], 6, 0x6fa87e4f); // 57
219 operation(I(), d, a, b, c, X[15], 10, 0xfe2ce6e0); // 58
220 operation(I(), c, d, a, b, X[ 6], 15, 0xa3014314); // 59
221 operation(I(), b, c, d, a, X[13], 21, 0x4e0811a1); // 60
222 operation(I(), a, b, c, d, X[ 4], 6, 0xf7537e82); // 61
223 operation(I(), d, a, b, c, X[11], 10, 0xbd3af235); // 62
224 operation(I(), c, d, a, b, X[ 2], 15, 0x2ad7d2bb); // 63
225 operation(I(), b, c, d, a, X[ 9], 21, 0xeb86d391); // 64
226
227 state[0] += a;
228 state[1] += b;
229 state[2] += c;
230 state[3] += d;
231
232 #if defined(SK_MD5_CLEAR_DATA)
233 // Clear sensitive information.
234 if (X == &storage) {
235 memset(storage, 0, sizeof(storage));
236 }
237 #endif
238 }
239
encode(uint8_t output[16],const uint32_t input[4])240 static void encode(uint8_t output[16], const uint32_t input[4]) {
241 for (size_t i = 0, j = 0; i < 4; i++, j += 4) {
242 output[j ] = (uint8_t) (input[i] & 0xff);
243 output[j+1] = (uint8_t)((input[i] >> 8) & 0xff);
244 output[j+2] = (uint8_t)((input[i] >> 16) & 0xff);
245 output[j+3] = (uint8_t)((input[i] >> 24) & 0xff);
246 }
247 }
248
encode(uint8_t output[8],const uint64_t input)249 static void encode(uint8_t output[8], const uint64_t input) {
250 output[0] = (uint8_t) (input & 0xff);
251 output[1] = (uint8_t)((input >> 8) & 0xff);
252 output[2] = (uint8_t)((input >> 16) & 0xff);
253 output[3] = (uint8_t)((input >> 24) & 0xff);
254 output[4] = (uint8_t)((input >> 32) & 0xff);
255 output[5] = (uint8_t)((input >> 40) & 0xff);
256 output[6] = (uint8_t)((input >> 48) & 0xff);
257 output[7] = (uint8_t)((input >> 56) & 0xff);
258 }
259
is_aligned(const void * pointer,size_t byte_count)260 static inline bool is_aligned(const void *pointer, size_t byte_count) {
261 return reinterpret_cast<uintptr_t>(pointer) % byte_count == 0;
262 }
263
decode(uint32_t storage[16],const uint8_t input[64])264 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]) {
265 #if defined(SK_CPU_LENDIAN) && defined(SK_CPU_FAST_UNALIGNED_ACCESS)
266 return reinterpret_cast<const uint32_t*>(input);
267 #else
268 #if defined(SK_CPU_LENDIAN)
269 if (is_aligned(input, 4)) {
270 return reinterpret_cast<const uint32_t*>(input);
271 }
272 #endif
273 for (size_t i = 0, j = 0; j < 64; i++, j += 4) {
274 storage[i] = ((uint32_t)input[j ]) |
275 (((uint32_t)input[j+1]) << 8) |
276 (((uint32_t)input[j+2]) << 16) |
277 (((uint32_t)input[j+3]) << 24);
278 }
279 return storage;
280 #endif
281 }
282