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