1 /*
2 * Copyright 2013 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 3174.
8 * http://www.ietf.org/rfc/rfc3174.txt
9 */
10
11 #include "SkTypes.h"
12 #include "SkSHA1.h"
13 #include <string.h>
14
15 /** SHA1 basic transformation. Transforms state based on block. */
16 static void transform(uint32_t state[5], const uint8_t block[64]);
17
18 /** Encodes input into output (5 big endian 32 bit values). */
19 static void encode(uint8_t output[20], const uint32_t input[5]);
20
21 /** Encodes input into output (big endian 64 bit value). */
22 static void encode(uint8_t output[8], const uint64_t input);
23
SkSHA1()24 SkSHA1::SkSHA1() : byteCount(0) {
25 // These are magic numbers from the specification. The first four are the same as MD5.
26 this->state[0] = 0x67452301;
27 this->state[1] = 0xefcdab89;
28 this->state[2] = 0x98badcfe;
29 this->state[3] = 0x10325476;
30 this->state[4] = 0xc3d2e1f0;
31 }
32
update(const uint8_t * input,size_t inputLength)33 void SkSHA1::update(const uint8_t* input, size_t inputLength) {
34 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
35 unsigned int bufferAvailable = 64 - bufferIndex;
36
37 unsigned int inputIndex;
38 if (inputLength >= bufferAvailable) {
39 if (bufferIndex) {
40 memcpy(&this->buffer[bufferIndex], input, bufferAvailable);
41 transform(this->state, this->buffer);
42 inputIndex = bufferAvailable;
43 } else {
44 inputIndex = 0;
45 }
46
47 for (; inputIndex + 63 < inputLength; inputIndex += 64) {
48 transform(this->state, &input[inputIndex]);
49 }
50
51 bufferIndex = 0;
52 } else {
53 inputIndex = 0;
54 }
55
56 memcpy(&this->buffer[bufferIndex], &input[inputIndex], inputLength - inputIndex);
57
58 this->byteCount += inputLength;
59 }
60
finish(Digest & digest)61 void SkSHA1::finish(Digest& digest) {
62 // Get the number of bits before padding.
63 uint8_t bits[8];
64 encode(bits, this->byteCount << 3);
65
66 // Pad out to 56 mod 64.
67 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
68 unsigned int paddingLength = (bufferIndex < 56) ? (56 - bufferIndex) : (120 - bufferIndex);
69 static uint8_t PADDING[64] = {
70 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
71 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
72 0, 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 };
75 this->update(PADDING, paddingLength);
76
77 // Append length (length before padding, will cause final update).
78 this->update(bits, 8);
79
80 // Write out digest.
81 encode(digest.data, this->state);
82
83 #if defined(SK_SHA1_CLEAR_DATA)
84 // Clear state.
85 memset(this, 0, sizeof(*this));
86 #endif
87 }
88
operator ()F189 struct F1 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
90 return (B & C) | ((~B) & D);
91 //return D ^ (B & (C ^ D));
92 //return (B & C) ^ ((~B) & D);
93 //return (B & C) + ((~B) & D);
94 //return _mm_or_ps(_mm_andnot_ps(B, D), _mm_and_ps(B, C)); //SSE2
95 //return vec_sel(D, C, B); //PPC
96 }};
97
operator ()F298 struct F2 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
99 return B ^ C ^ D;
100 }};
101
operator ()F3102 struct F3 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
103 return (B & C) | (B & D) | (C & D);
104 //return (B & C) | (D & (B | C));
105 //return (B & C) | (D & (B ^ C));
106 //return (B & C) + (D & (B ^ C));
107 //return (B & C) ^ (B & D) ^ (C & D);
108 }};
109
110 /** Rotates x left n bits. */
rotate_left(uint32_t x,uint8_t n)111 static inline uint32_t rotate_left(uint32_t x, uint8_t n) {
112 return (x << n) | (x >> (32 - n));
113 }
114
115 template <typename T>
operation(T operation,uint32_t A,uint32_t & B,uint32_t C,uint32_t D,uint32_t & E,uint32_t w,uint32_t k)116 static inline void operation(T operation,
117 uint32_t A, uint32_t& B, uint32_t C, uint32_t D, uint32_t& E,
118 uint32_t w, uint32_t k) {
119 E += rotate_left(A, 5) + operation(B, C, D) + w + k;
120 B = rotate_left(B, 30);
121 }
122
transform(uint32_t state[5],const uint8_t block[64])123 static void transform(uint32_t state[5], const uint8_t block[64]) {
124 uint32_t A = state[0], B = state[1], C = state[2], D = state[3], E = state[4];
125
126 // Round constants defined in SHA-1.
127 static const uint32_t K[] = {
128 0x5A827999, //sqrt(2) * 2^30
129 0x6ED9EBA1, //sqrt(3) * 2^30
130 0x8F1BBCDC, //sqrt(5) * 2^30
131 0xCA62C1D6, //sqrt(10) * 2^30
132 };
133
134 uint32_t W[80];
135
136 // Initialize the array W.
137 size_t i = 0;
138 for (size_t j = 0; i < 16; ++i, j += 4) {
139 W[i] = (((uint32_t)block[j ]) << 24) |
140 (((uint32_t)block[j+1]) << 16) |
141 (((uint32_t)block[j+2]) << 8) |
142 (((uint32_t)block[j+3]) );
143 }
144 for (; i < 80; ++i) {
145 W[i] = rotate_left(W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16], 1);
146 //The following is equivelent and speeds up SSE implementations, but slows non-SSE.
147 //W[i] = rotate_left(W[i-6] ^ W[i-16] ^ W[i-28] ^ W[i-32], 2);
148 }
149
150 // Round 1
151 operation(F1(), A, B, C, D, E, W[ 0], K[0]);
152 operation(F1(), E, A, B, C, D, W[ 1], K[0]);
153 operation(F1(), D, E, A, B, C, W[ 2], K[0]);
154 operation(F1(), C, D, E, A, B, W[ 3], K[0]);
155 operation(F1(), B, C, D, E, A, W[ 4], K[0]);
156 operation(F1(), A, B, C, D, E, W[ 5], K[0]);
157 operation(F1(), E, A, B, C, D, W[ 6], K[0]);
158 operation(F1(), D, E, A, B, C, W[ 7], K[0]);
159 operation(F1(), C, D, E, A, B, W[ 8], K[0]);
160 operation(F1(), B, C, D, E, A, W[ 9], K[0]);
161 operation(F1(), A, B, C, D, E, W[10], K[0]);
162 operation(F1(), E, A, B, C, D, W[11], K[0]);
163 operation(F1(), D, E, A, B, C, W[12], K[0]);
164 operation(F1(), C, D, E, A, B, W[13], K[0]);
165 operation(F1(), B, C, D, E, A, W[14], K[0]);
166 operation(F1(), A, B, C, D, E, W[15], K[0]);
167 operation(F1(), E, A, B, C, D, W[16], K[0]);
168 operation(F1(), D, E, A, B, C, W[17], K[0]);
169 operation(F1(), C, D, E, A, B, W[18], K[0]);
170 operation(F1(), B, C, D, E, A, W[19], K[0]);
171
172 // Round 2
173 operation(F2(), A, B, C, D, E, W[20], K[1]);
174 operation(F2(), E, A, B, C, D, W[21], K[1]);
175 operation(F2(), D, E, A, B, C, W[22], K[1]);
176 operation(F2(), C, D, E, A, B, W[23], K[1]);
177 operation(F2(), B, C, D, E, A, W[24], K[1]);
178 operation(F2(), A, B, C, D, E, W[25], K[1]);
179 operation(F2(), E, A, B, C, D, W[26], K[1]);
180 operation(F2(), D, E, A, B, C, W[27], K[1]);
181 operation(F2(), C, D, E, A, B, W[28], K[1]);
182 operation(F2(), B, C, D, E, A, W[29], K[1]);
183 operation(F2(), A, B, C, D, E, W[30], K[1]);
184 operation(F2(), E, A, B, C, D, W[31], K[1]);
185 operation(F2(), D, E, A, B, C, W[32], K[1]);
186 operation(F2(), C, D, E, A, B, W[33], K[1]);
187 operation(F2(), B, C, D, E, A, W[34], K[1]);
188 operation(F2(), A, B, C, D, E, W[35], K[1]);
189 operation(F2(), E, A, B, C, D, W[36], K[1]);
190 operation(F2(), D, E, A, B, C, W[37], K[1]);
191 operation(F2(), C, D, E, A, B, W[38], K[1]);
192 operation(F2(), B, C, D, E, A, W[39], K[1]);
193
194 // Round 3
195 operation(F3(), A, B, C, D, E, W[40], K[2]);
196 operation(F3(), E, A, B, C, D, W[41], K[2]);
197 operation(F3(), D, E, A, B, C, W[42], K[2]);
198 operation(F3(), C, D, E, A, B, W[43], K[2]);
199 operation(F3(), B, C, D, E, A, W[44], K[2]);
200 operation(F3(), A, B, C, D, E, W[45], K[2]);
201 operation(F3(), E, A, B, C, D, W[46], K[2]);
202 operation(F3(), D, E, A, B, C, W[47], K[2]);
203 operation(F3(), C, D, E, A, B, W[48], K[2]);
204 operation(F3(), B, C, D, E, A, W[49], K[2]);
205 operation(F3(), A, B, C, D, E, W[50], K[2]);
206 operation(F3(), E, A, B, C, D, W[51], K[2]);
207 operation(F3(), D, E, A, B, C, W[52], K[2]);
208 operation(F3(), C, D, E, A, B, W[53], K[2]);
209 operation(F3(), B, C, D, E, A, W[54], K[2]);
210 operation(F3(), A, B, C, D, E, W[55], K[2]);
211 operation(F3(), E, A, B, C, D, W[56], K[2]);
212 operation(F3(), D, E, A, B, C, W[57], K[2]);
213 operation(F3(), C, D, E, A, B, W[58], K[2]);
214 operation(F3(), B, C, D, E, A, W[59], K[2]);
215
216 // Round 4
217 operation(F2(), A, B, C, D, E, W[60], K[3]);
218 operation(F2(), E, A, B, C, D, W[61], K[3]);
219 operation(F2(), D, E, A, B, C, W[62], K[3]);
220 operation(F2(), C, D, E, A, B, W[63], K[3]);
221 operation(F2(), B, C, D, E, A, W[64], K[3]);
222 operation(F2(), A, B, C, D, E, W[65], K[3]);
223 operation(F2(), E, A, B, C, D, W[66], K[3]);
224 operation(F2(), D, E, A, B, C, W[67], K[3]);
225 operation(F2(), C, D, E, A, B, W[68], K[3]);
226 operation(F2(), B, C, D, E, A, W[69], K[3]);
227 operation(F2(), A, B, C, D, E, W[70], K[3]);
228 operation(F2(), E, A, B, C, D, W[71], K[3]);
229 operation(F2(), D, E, A, B, C, W[72], K[3]);
230 operation(F2(), C, D, E, A, B, W[73], K[3]);
231 operation(F2(), B, C, D, E, A, W[74], K[3]);
232 operation(F2(), A, B, C, D, E, W[75], K[3]);
233 operation(F2(), E, A, B, C, D, W[76], K[3]);
234 operation(F2(), D, E, A, B, C, W[77], K[3]);
235 operation(F2(), C, D, E, A, B, W[78], K[3]);
236 operation(F2(), B, C, D, E, A, W[79], K[3]);
237
238 state[0] += A;
239 state[1] += B;
240 state[2] += C;
241 state[3] += D;
242 state[4] += E;
243
244 #if defined(SK_SHA1_CLEAR_DATA)
245 // Clear sensitive information.
246 memset(W, 0, sizeof(W));
247 #endif
248 }
249
encode(uint8_t output[20],const uint32_t input[5])250 static void encode(uint8_t output[20], const uint32_t input[5]) {
251 for (size_t i = 0, j = 0; i < 5; i++, j += 4) {
252 output[j ] = (uint8_t)((input[i] >> 24) & 0xff);
253 output[j+1] = (uint8_t)((input[i] >> 16) & 0xff);
254 output[j+2] = (uint8_t)((input[i] >> 8) & 0xff);
255 output[j+3] = (uint8_t)((input[i] ) & 0xff);
256 }
257 }
258
encode(uint8_t output[8],const uint64_t input)259 static void encode(uint8_t output[8], const uint64_t input) {
260 output[0] = (uint8_t)((input >> 56) & 0xff);
261 output[1] = (uint8_t)((input >> 48) & 0xff);
262 output[2] = (uint8_t)((input >> 40) & 0xff);
263 output[3] = (uint8_t)((input >> 32) & 0xff);
264 output[4] = (uint8_t)((input >> 24) & 0xff);
265 output[5] = (uint8_t)((input >> 16) & 0xff);
266 output[6] = (uint8_t)((input >> 8) & 0xff);
267 output[7] = (uint8_t)((input ) & 0xff);
268 }
269