/* -*- 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; }