mfbt/SHA1.cpp
author Andrea Marchesini <amarchesini@mozilla.com>
Wed, 31 Oct 2018 18:30:18 +0100
changeset 500246 544498045a9cfe55968fa6500bffbc3181869fce
parent 338424 86cda9d3eaa2c6ca8c88801f44dcfaff22591ed8
child 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1486698 - Update Fetch+Stream implementation to throw when the stream is disturbed or locked, r=bz In this patch, I went through any place in DOM fetch code, where there are ReadableStreams and update the locked, disturbed, readable checks. Because we expose streams more often, we need an extra care in the use of ErrorResult objects. JS streams can now throw exceptions and we need to handle them. This patch also fixes a bug in FileStreamReader::CloseAndRelease() which could be called in case mReader creation fails.

/* -*- 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;
}