The Tor Browser / file comparison
comparison: mfbt/SHA1.cpp
mfbt/SHA1.cpp
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
equal
deleted
inserted
replaced
| -1:000000000000 | 0:a3ec5443f8e2 |
|---|---|
| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 #include "mozilla/Assertions.h" | |
| 6 #include "mozilla/Endian.h" | |
| 7 #include "mozilla/SHA1.h" | |
| 8 | |
| 9 #include <string.h> | |
| 10 | |
| 11 using mozilla::NativeEndian; | |
| 12 using mozilla::SHA1Sum; | |
| 13 | |
| 14 static inline uint32_t | |
| 15 SHA_ROTL(uint32_t t, uint32_t n) | |
| 16 { | |
| 17 MOZ_ASSERT(n < 32); | |
| 18 return (t << n) | (t >> (32 - n)); | |
| 19 } | |
| 20 | |
| 21 static void | |
| 22 shaCompress(volatile unsigned* X, const uint32_t* datain); | |
| 23 | |
| 24 #define SHA_F1(X, Y, Z) ((((Y) ^ (Z)) & (X)) ^ (Z)) | |
| 25 #define SHA_F2(X, Y, Z) ((X) ^ (Y) ^ (Z)) | |
| 26 #define SHA_F3(X, Y, Z) (((X) & (Y)) | ((Z) & ((X) | (Y)))) | |
| 27 #define SHA_F4(X, Y, Z) ((X) ^ (Y) ^ (Z)) | |
| 28 | |
| 29 #define SHA_MIX(n, a, b, c) XW(n) = SHA_ROTL(XW(a) ^ XW(b) ^ XW(c) ^XW(n), 1) | |
| 30 | |
| 31 SHA1Sum::SHA1Sum() | |
| 32 : size(0), mDone(false) | |
| 33 { | |
| 34 // Initialize H with constants from FIPS180-1. | |
| 35 H[0] = 0x67452301L; | |
| 36 H[1] = 0xefcdab89L; | |
| 37 H[2] = 0x98badcfeL; | |
| 38 H[3] = 0x10325476L; | |
| 39 H[4] = 0xc3d2e1f0L; | |
| 40 } | |
| 41 | |
| 42 /* | |
| 43 * Explanation of H array and index values: | |
| 44 * | |
| 45 * The context's H array is actually the concatenation of two arrays | |
| 46 * defined by SHA1, the H array of state variables (5 elements), | |
| 47 * and the W array of intermediate values, of which there are 16 elements. | |
| 48 * The W array starts at H[5], that is W[0] is H[5]. | |
| 49 * Although these values are defined as 32-bit values, we use 64-bit | |
| 50 * variables to hold them because the AMD64 stores 64 bit values in | |
| 51 * memory MUCH faster than it stores any smaller values. | |
| 52 * | |
| 53 * Rather than passing the context structure to shaCompress, we pass | |
| 54 * this combined array of H and W values. We do not pass the address | |
| 55 * of the first element of this array, but rather pass the address of an | |
| 56 * element in the middle of the array, element X. Presently X[0] is H[11]. | |
| 57 * So we pass the address of H[11] as the address of array X to shaCompress. | |
| 58 * Then shaCompress accesses the members of the array using positive AND | |
| 59 * negative indexes. | |
| 60 * | |
| 61 * Pictorially: (each element is 8 bytes) | |
| 62 * H | H0 H1 H2 H3 H4 W0 W1 W2 W3 W4 W5 W6 W7 W8 W9 Wa Wb Wc Wd We Wf | | |
| 63 * X |-11-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 X0 X1 X2 X3 X4 X5 X6 X7 X8 X9 | | |
| 64 * | |
| 65 * The byte offset from X[0] to any member of H and W is always | |
| 66 * representable in a signed 8-bit value, which will be encoded | |
| 67 * as a single byte offset in the X86-64 instruction set. | |
| 68 * If we didn't pass the address of H[11], and instead passed the | |
| 69 * address of H[0], the offsets to elements H[16] and above would be | |
| 70 * greater than 127, not representable in a signed 8-bit value, and the | |
| 71 * x86-64 instruction set would encode every such offset as a 32-bit | |
| 72 * signed number in each instruction that accessed element H[16] or | |
| 73 * higher. This results in much bigger and slower code. | |
| 74 */ | |
| 75 #define H2X 11 /* X[0] is H[11], and H[0] is X[-11] */ | |
| 76 #define W2X 6 /* X[0] is W[6], and W[0] is X[-6] */ | |
| 77 | |
| 78 /* | |
| 79 * SHA: Add data to context. | |
| 80 */ | |
| 81 void | |
| 82 SHA1Sum::update(const void* dataIn, uint32_t len) | |
| 83 { | |
| 84 MOZ_ASSERT(!mDone, "SHA1Sum can only be used to compute a single hash."); | |
| 85 | |
| 86 const uint8_t* data = static_cast<const uint8_t*>(dataIn); | |
| 87 | |
| 88 if (len == 0) | |
| 89 return; | |
| 90 | |
| 91 /* Accumulate the byte count. */ | |
| 92 unsigned int lenB = static_cast<unsigned int>(size) & 63U; | |
| 93 | |
| 94 size += len; | |
| 95 | |
| 96 /* Read the data into W and process blocks as they get full. */ | |
| 97 unsigned int togo; | |
| 98 if (lenB > 0) { | |
| 99 togo = 64U - lenB; | |
| 100 if (len < togo) | |
| 101 togo = len; | |
| 102 memcpy(u.b + lenB, data, togo); | |
| 103 len -= togo; | |
| 104 data += togo; | |
| 105 lenB = (lenB + togo) & 63U; | |
| 106 if (!lenB) | |
| 107 shaCompress(&H[H2X], u.w); | |
| 108 } | |
| 109 | |
| 110 while (len >= 64U) { | |
| 111 len -= 64U; | |
| 112 shaCompress(&H[H2X], reinterpret_cast<const uint32_t*>(data)); | |
| 113 data += 64U; | |
| 114 } | |
| 115 | |
| 116 if (len > 0) | |
| 117 memcpy(u.b, data, len); | |
| 118 } | |
| 119 | |
| 120 | |
| 121 /* | |
| 122 * SHA: Generate hash value | |
| 123 */ | |
| 124 void | |
| 125 SHA1Sum::finish(SHA1Sum::Hash& hashOut) | |
| 126 { | |
| 127 MOZ_ASSERT(!mDone, "SHA1Sum can only be used to compute a single hash."); | |
| 128 | |
| 129 uint64_t size2 = size; | |
| 130 uint32_t lenB = uint32_t(size2) & 63; | |
| 131 | |
| 132 static const uint8_t bulk_pad[64] = | |
| 133 { 0x80,0,0,0,0,0,0,0,0,0, | |
| 134 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, | |
| 135 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; | |
| 136 | |
| 137 /* Pad with a binary 1 (e.g. 0x80), then zeroes, then length in bits. */ | |
| 138 update(bulk_pad, (((55 + 64) - lenB) & 63) + 1); | |
| 139 MOZ_ASSERT((uint32_t(size) & 63) == 56); | |
| 140 | |
| 141 /* Convert size from bytes to bits. */ | |
| 142 size2 <<= 3; | |
| 143 u.w[14] = NativeEndian::swapToBigEndian(uint32_t(size2 >> 32)); | |
| 144 u.w[15] = NativeEndian::swapToBigEndian(uint32_t(size2)); | |
| 145 shaCompress(&H[H2X], u.w); | |
| 146 | |
| 147 /* Output hash. */ | |
| 148 u.w[0] = NativeEndian::swapToBigEndian(H[0]); | |
| 149 u.w[1] = NativeEndian::swapToBigEndian(H[1]); | |
| 150 u.w[2] = NativeEndian::swapToBigEndian(H[2]); | |
| 151 u.w[3] = NativeEndian::swapToBigEndian(H[3]); | |
| 152 u.w[4] = NativeEndian::swapToBigEndian(H[4]); | |
| 153 memcpy(hashOut, u.w, 20); | |
| 154 mDone = true; | |
| 155 } | |
| 156 | |
| 157 /* | |
| 158 * SHA: Compression function, unrolled. | |
| 159 * | |
| 160 * Some operations in shaCompress are done as 5 groups of 16 operations. | |
| 161 * Others are done as 4 groups of 20 operations. | |
| 162 * The code below shows that structure. | |
| 163 * | |
| 164 * The functions that compute the new values of the 5 state variables | |
| 165 * A-E are done in 4 groups of 20 operations (or you may also think | |
| 166 * of them as being done in 16 groups of 5 operations). They are | |
| 167 * done by the SHA_RNDx macros below, in the right column. | |
| 168 * | |
| 169 * The functions that set the 16 values of the W array are done in | |
| 170 * 5 groups of 16 operations. The first group is done by the | |
| 171 * LOAD macros below, the latter 4 groups are done by SHA_MIX below, | |
| 172 * in the left column. | |
| 173 * | |
| 174 * gcc's optimizer observes that each member of the W array is assigned | |
| 175 * a value 5 times in this code. It reduces the number of store | |
| 176 * operations done to the W array in the context (that is, in the X array) | |
| 177 * by creating a W array on the stack, and storing the W values there for | |
| 178 * the first 4 groups of operations on W, and storing the values in the | |
| 179 * context's W array only in the fifth group. This is undesirable. | |
| 180 * It is MUCH bigger code than simply using the context's W array, because | |
| 181 * all the offsets to the W array in the stack are 32-bit signed offsets, | |
| 182 * and it is no faster than storing the values in the context's W array. | |
| 183 * | |
| 184 * The original code for sha_fast.c prevented this creation of a separate | |
| 185 * W array in the stack by creating a W array of 80 members, each of | |
| 186 * whose elements is assigned only once. It also separated the computations | |
| 187 * of the W array values and the computations of the values for the 5 | |
| 188 * state variables into two separate passes, W's, then A-E's so that the | |
| 189 * second pass could be done all in registers (except for accessing the W | |
| 190 * array) on machines with fewer registers. The method is suboptimal | |
| 191 * for machines with enough registers to do it all in one pass, and it | |
| 192 * necessitates using many instructions with 32-bit offsets. | |
| 193 * | |
| 194 * This code eliminates the separate W array on the stack by a completely | |
| 195 * different means: by declaring the X array volatile. This prevents | |
| 196 * the optimizer from trying to reduce the use of the X array by the | |
| 197 * creation of a MORE expensive W array on the stack. The result is | |
| 198 * that all instructions use signed 8-bit offsets and not 32-bit offsets. | |
| 199 * | |
| 200 * The combination of this code and the -O3 optimizer flag on GCC 3.4.3 | |
| 201 * results in code that is 3 times faster than the previous NSS sha_fast | |
| 202 * code on AMD64. | |
| 203 */ | |
| 204 static void | |
| 205 shaCompress(volatile unsigned *X, const uint32_t *inbuf) | |
| 206 { | |
| 207 unsigned A, B, C, D, E; | |
| 208 | |
| 209 #define XH(n) X[n - H2X] | |
| 210 #define XW(n) X[n - W2X] | |
| 211 | |
| 212 #define K0 0x5a827999L | |
| 213 #define K1 0x6ed9eba1L | |
| 214 #define K2 0x8f1bbcdcL | |
| 215 #define K3 0xca62c1d6L | |
| 216 | |
| 217 #define SHA_RND1(a, b, c, d, e, n) \ | |
| 218 a = SHA_ROTL(b, 5) + SHA_F1(c, d, e) + a + XW(n) + K0; c = SHA_ROTL(c, 30) | |
| 219 #define SHA_RND2(a, b, c, d, e, n) \ | |
| 220 a = SHA_ROTL(b, 5) + SHA_F2(c, d, e) + a + XW(n) + K1; c = SHA_ROTL(c, 30) | |
| 221 #define SHA_RND3(a, b, c, d, e, n) \ | |
| 222 a = SHA_ROTL(b, 5) + SHA_F3(c, d, e) + a + XW(n) + K2; c = SHA_ROTL(c, 30) | |
| 223 #define SHA_RND4(a, b, c, d, e, n) \ | |
| 224 a = SHA_ROTL(b ,5) + SHA_F4(c, d, e) + a + XW(n) + K3; c = SHA_ROTL(c, 30) | |
| 225 | |
| 226 #define LOAD(n) XW(n) = NativeEndian::swapToBigEndian(inbuf[n]) | |
| 227 | |
| 228 A = XH(0); | |
| 229 B = XH(1); | |
| 230 C = XH(2); | |
| 231 D = XH(3); | |
| 232 E = XH(4); | |
| 233 | |
| 234 LOAD(0); SHA_RND1(E,A,B,C,D, 0); | |
| 235 LOAD(1); SHA_RND1(D,E,A,B,C, 1); | |
| 236 LOAD(2); SHA_RND1(C,D,E,A,B, 2); | |
| 237 LOAD(3); SHA_RND1(B,C,D,E,A, 3); | |
| 238 LOAD(4); SHA_RND1(A,B,C,D,E, 4); | |
| 239 LOAD(5); SHA_RND1(E,A,B,C,D, 5); | |
| 240 LOAD(6); SHA_RND1(D,E,A,B,C, 6); | |
| 241 LOAD(7); SHA_RND1(C,D,E,A,B, 7); | |
| 242 LOAD(8); SHA_RND1(B,C,D,E,A, 8); | |
| 243 LOAD(9); SHA_RND1(A,B,C,D,E, 9); | |
| 244 LOAD(10); SHA_RND1(E,A,B,C,D,10); | |
| 245 LOAD(11); SHA_RND1(D,E,A,B,C,11); | |
| 246 LOAD(12); SHA_RND1(C,D,E,A,B,12); | |
| 247 LOAD(13); SHA_RND1(B,C,D,E,A,13); | |
| 248 LOAD(14); SHA_RND1(A,B,C,D,E,14); | |
| 249 LOAD(15); SHA_RND1(E,A,B,C,D,15); | |
| 250 | |
| 251 SHA_MIX( 0, 13, 8, 2); SHA_RND1(D,E,A,B,C, 0); | |
| 252 SHA_MIX( 1, 14, 9, 3); SHA_RND1(C,D,E,A,B, 1); | |
| 253 SHA_MIX( 2, 15, 10, 4); SHA_RND1(B,C,D,E,A, 2); | |
| 254 SHA_MIX( 3, 0, 11, 5); SHA_RND1(A,B,C,D,E, 3); | |
| 255 | |
| 256 SHA_MIX( 4, 1, 12, 6); SHA_RND2(E,A,B,C,D, 4); | |
| 257 SHA_MIX( 5, 2, 13, 7); SHA_RND2(D,E,A,B,C, 5); | |
| 258 SHA_MIX( 6, 3, 14, 8); SHA_RND2(C,D,E,A,B, 6); | |
| 259 SHA_MIX( 7, 4, 15, 9); SHA_RND2(B,C,D,E,A, 7); | |
| 260 SHA_MIX( 8, 5, 0, 10); SHA_RND2(A,B,C,D,E, 8); | |
| 261 SHA_MIX( 9, 6, 1, 11); SHA_RND2(E,A,B,C,D, 9); | |
| 262 SHA_MIX(10, 7, 2, 12); SHA_RND2(D,E,A,B,C,10); | |
| 263 SHA_MIX(11, 8, 3, 13); SHA_RND2(C,D,E,A,B,11); | |
| 264 SHA_MIX(12, 9, 4, 14); SHA_RND2(B,C,D,E,A,12); | |
| 265 SHA_MIX(13, 10, 5, 15); SHA_RND2(A,B,C,D,E,13); | |
| 266 SHA_MIX(14, 11, 6, 0); SHA_RND2(E,A,B,C,D,14); | |
| 267 SHA_MIX(15, 12, 7, 1); SHA_RND2(D,E,A,B,C,15); | |
| 268 | |
| 269 SHA_MIX( 0, 13, 8, 2); SHA_RND2(C,D,E,A,B, 0); | |
| 270 SHA_MIX( 1, 14, 9, 3); SHA_RND2(B,C,D,E,A, 1); | |
| 271 SHA_MIX( 2, 15, 10, 4); SHA_RND2(A,B,C,D,E, 2); | |
| 272 SHA_MIX( 3, 0, 11, 5); SHA_RND2(E,A,B,C,D, 3); | |
| 273 SHA_MIX( 4, 1, 12, 6); SHA_RND2(D,E,A,B,C, 4); | |
| 274 SHA_MIX( 5, 2, 13, 7); SHA_RND2(C,D,E,A,B, 5); | |
| 275 SHA_MIX( 6, 3, 14, 8); SHA_RND2(B,C,D,E,A, 6); | |
| 276 SHA_MIX( 7, 4, 15, 9); SHA_RND2(A,B,C,D,E, 7); | |
| 277 | |
| 278 SHA_MIX( 8, 5, 0, 10); SHA_RND3(E,A,B,C,D, 8); | |
| 279 SHA_MIX( 9, 6, 1, 11); SHA_RND3(D,E,A,B,C, 9); | |
| 280 SHA_MIX(10, 7, 2, 12); SHA_RND3(C,D,E,A,B,10); | |
| 281 SHA_MIX(11, 8, 3, 13); SHA_RND3(B,C,D,E,A,11); | |
| 282 SHA_MIX(12, 9, 4, 14); SHA_RND3(A,B,C,D,E,12); | |
| 283 SHA_MIX(13, 10, 5, 15); SHA_RND3(E,A,B,C,D,13); | |
| 284 SHA_MIX(14, 11, 6, 0); SHA_RND3(D,E,A,B,C,14); | |
| 285 SHA_MIX(15, 12, 7, 1); SHA_RND3(C,D,E,A,B,15); | |
| 286 | |
| 287 SHA_MIX( 0, 13, 8, 2); SHA_RND3(B,C,D,E,A, 0); | |
| 288 SHA_MIX( 1, 14, 9, 3); SHA_RND3(A,B,C,D,E, 1); | |
| 289 SHA_MIX( 2, 15, 10, 4); SHA_RND3(E,A,B,C,D, 2); | |
| 290 SHA_MIX( 3, 0, 11, 5); SHA_RND3(D,E,A,B,C, 3); | |
| 291 SHA_MIX( 4, 1, 12, 6); SHA_RND3(C,D,E,A,B, 4); | |
| 292 SHA_MIX( 5, 2, 13, 7); SHA_RND3(B,C,D,E,A, 5); | |
| 293 SHA_MIX( 6, 3, 14, 8); SHA_RND3(A,B,C,D,E, 6); | |
| 294 SHA_MIX( 7, 4, 15, 9); SHA_RND3(E,A,B,C,D, 7); | |
| 295 SHA_MIX( 8, 5, 0, 10); SHA_RND3(D,E,A,B,C, 8); | |
| 296 SHA_MIX( 9, 6, 1, 11); SHA_RND3(C,D,E,A,B, 9); | |
| 297 SHA_MIX(10, 7, 2, 12); SHA_RND3(B,C,D,E,A,10); | |
| 298 SHA_MIX(11, 8, 3, 13); SHA_RND3(A,B,C,D,E,11); | |
| 299 | |
| 300 SHA_MIX(12, 9, 4, 14); SHA_RND4(E,A,B,C,D,12); | |
| 301 SHA_MIX(13, 10, 5, 15); SHA_RND4(D,E,A,B,C,13); | |
| 302 SHA_MIX(14, 11, 6, 0); SHA_RND4(C,D,E,A,B,14); | |
| 303 SHA_MIX(15, 12, 7, 1); SHA_RND4(B,C,D,E,A,15); | |
| 304 | |
| 305 SHA_MIX( 0, 13, 8, 2); SHA_RND4(A,B,C,D,E, 0); | |
| 306 SHA_MIX( 1, 14, 9, 3); SHA_RND4(E,A,B,C,D, 1); | |
| 307 SHA_MIX( 2, 15, 10, 4); SHA_RND4(D,E,A,B,C, 2); | |
| 308 SHA_MIX( 3, 0, 11, 5); SHA_RND4(C,D,E,A,B, 3); | |
| 309 SHA_MIX( 4, 1, 12, 6); SHA_RND4(B,C,D,E,A, 4); | |
| 310 SHA_MIX( 5, 2, 13, 7); SHA_RND4(A,B,C,D,E, 5); | |
| 311 SHA_MIX( 6, 3, 14, 8); SHA_RND4(E,A,B,C,D, 6); | |
| 312 SHA_MIX( 7, 4, 15, 9); SHA_RND4(D,E,A,B,C, 7); | |
| 313 SHA_MIX( 8, 5, 0, 10); SHA_RND4(C,D,E,A,B, 8); | |
| 314 SHA_MIX( 9, 6, 1, 11); SHA_RND4(B,C,D,E,A, 9); | |
| 315 SHA_MIX(10, 7, 2, 12); SHA_RND4(A,B,C,D,E,10); | |
| 316 SHA_MIX(11, 8, 3, 13); SHA_RND4(E,A,B,C,D,11); | |
| 317 SHA_MIX(12, 9, 4, 14); SHA_RND4(D,E,A,B,C,12); | |
| 318 SHA_MIX(13, 10, 5, 15); SHA_RND4(C,D,E,A,B,13); | |
| 319 SHA_MIX(14, 11, 6, 0); SHA_RND4(B,C,D,E,A,14); | |
| 320 SHA_MIX(15, 12, 7, 1); SHA_RND4(A,B,C,D,E,15); | |
| 321 | |
| 322 XH(0) += A; | |
| 323 XH(1) += B; | |
| 324 XH(2) += C; | |
| 325 XH(3) += D; | |
| 326 XH(4) += E; | |
| 327 } |
