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Diffstat (limited to 'mfbt/SHA1.cpp')
| -rw-r--r-- | mfbt/SHA1.cpp | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/mfbt/SHA1.cpp b/mfbt/SHA1.cpp new file mode 100644 index 000000000..f8968c3e1 --- /dev/null +++ b/mfbt/SHA1.cpp @@ -0,0 +1,333 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "mozilla/Assertions.h" +#include "mozilla/EndianUtils.h" +#include "mozilla/SHA1.h" + +#include <string.h> + +using mozilla::NativeEndian; +using mozilla::SHA1Sum; + +static inline uint32_t +SHA_ROTL(uint32_t aT, uint32_t aN) +{ + MOZ_ASSERT(aN < 32); + return (aT << aN) | (aT >> (32 - aN)); +} + +static void +shaCompress(volatile unsigned* aX, const uint32_t* aBuf); + +#define SHA_F1(X, Y, Z) ((((Y) ^ (Z)) & (X)) ^ (Z)) +#define SHA_F2(X, Y, Z) ((X) ^ (Y) ^ (Z)) +#define SHA_F3(X, Y, Z) (((X) & (Y)) | ((Z) & ((X) | (Y)))) +#define SHA_F4(X, Y, Z) ((X) ^ (Y) ^ (Z)) + +#define SHA_MIX(n, a, b, c) XW(n) = SHA_ROTL(XW(a) ^ XW(b) ^ XW(c) ^XW(n), 1) + +SHA1Sum::SHA1Sum() + : mSize(0), mDone(false) +{ + // Initialize H with constants from FIPS180-1. + mH[0] = 0x67452301L; + mH[1] = 0xefcdab89L; + mH[2] = 0x98badcfeL; + mH[3] = 0x10325476L; + mH[4] = 0xc3d2e1f0L; +} + +/* + * Explanation of H array and index values: + * + * The context's H array is actually the concatenation of two arrays + * defined by SHA1, the H array of state variables (5 elements), + * and the W array of intermediate values, of which there are 16 elements. + * The W array starts at H[5], that is W[0] is H[5]. + * Although these values are defined as 32-bit values, we use 64-bit + * variables to hold them because the AMD64 stores 64 bit values in + * memory MUCH faster than it stores any smaller values. + * + * Rather than passing the context structure to shaCompress, we pass + * this combined array of H and W values. We do not pass the address + * of the first element of this array, but rather pass the address of an + * element in the middle of the array, element X. Presently X[0] is H[11]. + * So we pass the address of H[11] as the address of array X to shaCompress. + * Then shaCompress accesses the members of the array using positive AND + * negative indexes. + * + * Pictorially: (each element is 8 bytes) + * H | H0 H1 H2 H3 H4 W0 W1 W2 W3 W4 W5 W6 W7 W8 W9 Wa Wb Wc Wd We Wf | + * X |-11-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 X0 X1 X2 X3 X4 X5 X6 X7 X8 X9 | + * + * The byte offset from X[0] to any member of H and W is always + * representable in a signed 8-bit value, which will be encoded + * as a single byte offset in the X86-64 instruction set. + * If we didn't pass the address of H[11], and instead passed the + * address of H[0], the offsets to elements H[16] and above would be + * greater than 127, not representable in a signed 8-bit value, and the + * x86-64 instruction set would encode every such offset as a 32-bit + * signed number in each instruction that accessed element H[16] or + * higher. This results in much bigger and slower code. + */ +#define H2X 11 /* X[0] is H[11], and H[0] is X[-11] */ +#define W2X 6 /* X[0] is W[6], and W[0] is X[-6] */ + +/* + * SHA: Add data to context. + */ +void +SHA1Sum::update(const void* aData, uint32_t aLen) +{ + MOZ_ASSERT(!mDone, "SHA1Sum can only be used to compute a single hash."); + + const uint8_t* data = static_cast<const uint8_t*>(aData); + + if (aLen == 0) { + return; + } + + /* Accumulate the byte count. */ + unsigned int lenB = static_cast<unsigned int>(mSize) & 63U; + + mSize += aLen; + + /* Read the data into W and process blocks as they get full. */ + unsigned int togo; + if (lenB > 0) { + togo = 64U - lenB; + if (aLen < togo) { + togo = aLen; + } + memcpy(mU.mB + lenB, data, togo); + aLen -= togo; + data += togo; + lenB = (lenB + togo) & 63U; + if (!lenB) { + shaCompress(&mH[H2X], mU.mW); + } + } + + while (aLen >= 64U) { + aLen -= 64U; + shaCompress(&mH[H2X], reinterpret_cast<const uint32_t*>(data)); + data += 64U; + } + + if (aLen > 0) { + memcpy(mU.mB, data, aLen); + } +} + + +/* + * SHA: Generate hash value + */ +void +SHA1Sum::finish(SHA1Sum::Hash& aHashOut) +{ + MOZ_ASSERT(!mDone, "SHA1Sum can only be used to compute a single hash."); + + uint64_t size = mSize; + uint32_t lenB = uint32_t(size) & 63; + + static const uint8_t bulk_pad[64] = + { 0x80,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; + + /* Pad with a binary 1 (e.g. 0x80), then zeroes, then length in bits. */ + update(bulk_pad, (((55 + 64) - lenB) & 63) + 1); + MOZ_ASSERT((uint32_t(mSize) & 63) == 56); + + /* Convert size from bytes to bits. */ + size <<= 3; + mU.mW[14] = NativeEndian::swapToBigEndian(uint32_t(size >> 32)); + mU.mW[15] = NativeEndian::swapToBigEndian(uint32_t(size)); + shaCompress(&mH[H2X], mU.mW); + + /* Output hash. */ + mU.mW[0] = NativeEndian::swapToBigEndian(mH[0]); + mU.mW[1] = NativeEndian::swapToBigEndian(mH[1]); + mU.mW[2] = NativeEndian::swapToBigEndian(mH[2]); + mU.mW[3] = NativeEndian::swapToBigEndian(mH[3]); + mU.mW[4] = NativeEndian::swapToBigEndian(mH[4]); + memcpy(aHashOut, mU.mW, 20); + mDone = true; +} + +/* + * SHA: Compression function, unrolled. + * + * Some operations in shaCompress are done as 5 groups of 16 operations. + * Others are done as 4 groups of 20 operations. + * The code below shows that structure. + * + * The functions that compute the new values of the 5 state variables + * A-E are done in 4 groups of 20 operations (or you may also think + * of them as being done in 16 groups of 5 operations). They are + * done by the SHA_RNDx macros below, in the right column. + * + * The functions that set the 16 values of the W array are done in + * 5 groups of 16 operations. The first group is done by the + * LOAD macros below, the latter 4 groups are done by SHA_MIX below, + * in the left column. + * + * gcc's optimizer observes that each member of the W array is assigned + * a value 5 times in this code. It reduces the number of store + * operations done to the W array in the context (that is, in the X array) + * by creating a W array on the stack, and storing the W values there for + * the first 4 groups of operations on W, and storing the values in the + * context's W array only in the fifth group. This is undesirable. + * It is MUCH bigger code than simply using the context's W array, because + * all the offsets to the W array in the stack are 32-bit signed offsets, + * and it is no faster than storing the values in the context's W array. + * + * The original code for sha_fast.c prevented this creation of a separate + * W array in the stack by creating a W array of 80 members, each of + * whose elements is assigned only once. It also separated the computations + * of the W array values and the computations of the values for the 5 + * state variables into two separate passes, W's, then A-E's so that the + * second pass could be done all in registers (except for accessing the W + * array) on machines with fewer registers. The method is suboptimal + * for machines with enough registers to do it all in one pass, and it + * necessitates using many instructions with 32-bit offsets. + * + * This code eliminates the separate W array on the stack by a completely + * different means: by declaring the X array volatile. This prevents + * the optimizer from trying to reduce the use of the X array by the + * creation of a MORE expensive W array on the stack. The result is + * that all instructions use signed 8-bit offsets and not 32-bit offsets. + * + * The combination of this code and the -O3 optimizer flag on GCC 3.4.3 + * results in code that is 3 times faster than the previous NSS sha_fast + * code on AMD64. + */ +static void +shaCompress(volatile unsigned* aX, const uint32_t* aBuf) +{ + unsigned A, B, C, D, E; + +#define XH(n) aX[n - H2X] +#define XW(n) aX[n - W2X] + +#define K0 0x5a827999L +#define K1 0x6ed9eba1L +#define K2 0x8f1bbcdcL +#define K3 0xca62c1d6L + +#define SHA_RND1(a, b, c, d, e, n) \ + a = SHA_ROTL(b, 5) + SHA_F1(c, d, e) + a + XW(n) + K0; c = SHA_ROTL(c, 30) +#define SHA_RND2(a, b, c, d, e, n) \ + a = SHA_ROTL(b, 5) + SHA_F2(c, d, e) + a + XW(n) + K1; c = SHA_ROTL(c, 30) +#define SHA_RND3(a, b, c, d, e, n) \ + a = SHA_ROTL(b, 5) + SHA_F3(c, d, e) + a + XW(n) + K2; c = SHA_ROTL(c, 30) +#define SHA_RND4(a, b, c, d, e, n) \ + a = SHA_ROTL(b ,5) + SHA_F4(c, d, e) + a + XW(n) + K3; c = SHA_ROTL(c, 30) + +#define LOAD(n) XW(n) = NativeEndian::swapToBigEndian(aBuf[n]) + + A = XH(0); + B = XH(1); + C = XH(2); + D = XH(3); + E = XH(4); + + LOAD(0); SHA_RND1(E,A,B,C,D, 0); + LOAD(1); SHA_RND1(D,E,A,B,C, 1); + LOAD(2); SHA_RND1(C,D,E,A,B, 2); + LOAD(3); SHA_RND1(B,C,D,E,A, 3); + LOAD(4); SHA_RND1(A,B,C,D,E, 4); + LOAD(5); SHA_RND1(E,A,B,C,D, 5); + LOAD(6); SHA_RND1(D,E,A,B,C, 6); + LOAD(7); SHA_RND1(C,D,E,A,B, 7); + LOAD(8); SHA_RND1(B,C,D,E,A, 8); + LOAD(9); SHA_RND1(A,B,C,D,E, 9); + LOAD(10); SHA_RND1(E,A,B,C,D,10); + LOAD(11); SHA_RND1(D,E,A,B,C,11); + LOAD(12); SHA_RND1(C,D,E,A,B,12); + LOAD(13); SHA_RND1(B,C,D,E,A,13); + LOAD(14); SHA_RND1(A,B,C,D,E,14); + LOAD(15); SHA_RND1(E,A,B,C,D,15); + + SHA_MIX( 0, 13, 8, 2); SHA_RND1(D,E,A,B,C, 0); + SHA_MIX( 1, 14, 9, 3); SHA_RND1(C,D,E,A,B, 1); + SHA_MIX( 2, 15, 10, 4); SHA_RND1(B,C,D,E,A, 2); + SHA_MIX( 3, 0, 11, 5); SHA_RND1(A,B,C,D,E, 3); + + SHA_MIX( 4, 1, 12, 6); SHA_RND2(E,A,B,C,D, 4); + SHA_MIX( 5, 2, 13, 7); SHA_RND2(D,E,A,B,C, 5); + SHA_MIX( 6, 3, 14, 8); SHA_RND2(C,D,E,A,B, 6); + SHA_MIX( 7, 4, 15, 9); SHA_RND2(B,C,D,E,A, 7); + SHA_MIX( 8, 5, 0, 10); SHA_RND2(A,B,C,D,E, 8); + SHA_MIX( 9, 6, 1, 11); SHA_RND2(E,A,B,C,D, 9); + SHA_MIX(10, 7, 2, 12); SHA_RND2(D,E,A,B,C,10); + SHA_MIX(11, 8, 3, 13); SHA_RND2(C,D,E,A,B,11); + SHA_MIX(12, 9, 4, 14); SHA_RND2(B,C,D,E,A,12); + SHA_MIX(13, 10, 5, 15); SHA_RND2(A,B,C,D,E,13); + SHA_MIX(14, 11, 6, 0); SHA_RND2(E,A,B,C,D,14); + SHA_MIX(15, 12, 7, 1); SHA_RND2(D,E,A,B,C,15); + + SHA_MIX( 0, 13, 8, 2); SHA_RND2(C,D,E,A,B, 0); + SHA_MIX( 1, 14, 9, 3); SHA_RND2(B,C,D,E,A, 1); + SHA_MIX( 2, 15, 10, 4); SHA_RND2(A,B,C,D,E, 2); + SHA_MIX( 3, 0, 11, 5); SHA_RND2(E,A,B,C,D, 3); + SHA_MIX( 4, 1, 12, 6); SHA_RND2(D,E,A,B,C, 4); + SHA_MIX( 5, 2, 13, 7); SHA_RND2(C,D,E,A,B, 5); + SHA_MIX( 6, 3, 14, 8); SHA_RND2(B,C,D,E,A, 6); + SHA_MIX( 7, 4, 15, 9); SHA_RND2(A,B,C,D,E, 7); + + SHA_MIX( 8, 5, 0, 10); SHA_RND3(E,A,B,C,D, 8); + SHA_MIX( 9, 6, 1, 11); SHA_RND3(D,E,A,B,C, 9); + SHA_MIX(10, 7, 2, 12); SHA_RND3(C,D,E,A,B,10); + SHA_MIX(11, 8, 3, 13); SHA_RND3(B,C,D,E,A,11); + SHA_MIX(12, 9, 4, 14); SHA_RND3(A,B,C,D,E,12); + SHA_MIX(13, 10, 5, 15); SHA_RND3(E,A,B,C,D,13); + SHA_MIX(14, 11, 6, 0); SHA_RND3(D,E,A,B,C,14); + SHA_MIX(15, 12, 7, 1); SHA_RND3(C,D,E,A,B,15); + + SHA_MIX( 0, 13, 8, 2); SHA_RND3(B,C,D,E,A, 0); + SHA_MIX( 1, 14, 9, 3); SHA_RND3(A,B,C,D,E, 1); + SHA_MIX( 2, 15, 10, 4); SHA_RND3(E,A,B,C,D, 2); + SHA_MIX( 3, 0, 11, 5); SHA_RND3(D,E,A,B,C, 3); + SHA_MIX( 4, 1, 12, 6); SHA_RND3(C,D,E,A,B, 4); + SHA_MIX( 5, 2, 13, 7); SHA_RND3(B,C,D,E,A, 5); + SHA_MIX( 6, 3, 14, 8); SHA_RND3(A,B,C,D,E, 6); + SHA_MIX( 7, 4, 15, 9); SHA_RND3(E,A,B,C,D, 7); + SHA_MIX( 8, 5, 0, 10); SHA_RND3(D,E,A,B,C, 8); + SHA_MIX( 9, 6, 1, 11); SHA_RND3(C,D,E,A,B, 9); + SHA_MIX(10, 7, 2, 12); SHA_RND3(B,C,D,E,A,10); + SHA_MIX(11, 8, 3, 13); SHA_RND3(A,B,C,D,E,11); + + SHA_MIX(12, 9, 4, 14); SHA_RND4(E,A,B,C,D,12); + SHA_MIX(13, 10, 5, 15); SHA_RND4(D,E,A,B,C,13); + SHA_MIX(14, 11, 6, 0); SHA_RND4(C,D,E,A,B,14); + SHA_MIX(15, 12, 7, 1); SHA_RND4(B,C,D,E,A,15); + + SHA_MIX( 0, 13, 8, 2); SHA_RND4(A,B,C,D,E, 0); + SHA_MIX( 1, 14, 9, 3); SHA_RND4(E,A,B,C,D, 1); + SHA_MIX( 2, 15, 10, 4); SHA_RND4(D,E,A,B,C, 2); + SHA_MIX( 3, 0, 11, 5); SHA_RND4(C,D,E,A,B, 3); + SHA_MIX( 4, 1, 12, 6); SHA_RND4(B,C,D,E,A, 4); + SHA_MIX( 5, 2, 13, 7); SHA_RND4(A,B,C,D,E, 5); + SHA_MIX( 6, 3, 14, 8); SHA_RND4(E,A,B,C,D, 6); + SHA_MIX( 7, 4, 15, 9); SHA_RND4(D,E,A,B,C, 7); + SHA_MIX( 8, 5, 0, 10); SHA_RND4(C,D,E,A,B, 8); + SHA_MIX( 9, 6, 1, 11); SHA_RND4(B,C,D,E,A, 9); + SHA_MIX(10, 7, 2, 12); SHA_RND4(A,B,C,D,E,10); + SHA_MIX(11, 8, 3, 13); SHA_RND4(E,A,B,C,D,11); + SHA_MIX(12, 9, 4, 14); SHA_RND4(D,E,A,B,C,12); + SHA_MIX(13, 10, 5, 15); SHA_RND4(C,D,E,A,B,13); + SHA_MIX(14, 11, 6, 0); SHA_RND4(B,C,D,E,A,14); + SHA_MIX(15, 12, 7, 1); SHA_RND4(A,B,C,D,E,15); + + XH(0) += A; + XH(1) += B; + XH(2) += C; + XH(3) += D; + XH(4) += E; +} |