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gecko-dev
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gecko-dev/mfbt/SHA1.cpp

346 строки
12 KiB
C++
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/* 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/SHA1.h"
#include <string.h>
// FIXME: We should probably create a more complete mfbt/Endian.h. This assumes
// that any compiler that doesn't define these macros is little endian.
#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__)
# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
# define MOZ_IS_LITTLE_ENDIAN
# endif
#else
# define MOZ_IS_LITTLE_ENDIAN
#endif
using mozilla::SHA1Sum;
static inline uint32_t
SHA_ROTL(uint32_t t, uint32_t n)
{
MOZ_ASSERT(n < 32);
return (t << n) | (t >> (32 - n));
}
static inline unsigned
SHA_HTONL(unsigned x)
{
#ifdef MOZ_IS_LITTLE_ENDIAN
const unsigned int mask = 0x00FF00FF;
x = (x << 16) | (x >> 16);
return ((x & mask) << 8) | ((x >> 8) & mask);
#else
return x;
#endif
}
static void
shaCompress(volatile unsigned* X, const uint32_t* datain);
#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()
: size(0), mDone(false)
{
// Initialize H with constants from FIPS180-1.
H[0] = 0x67452301L;
H[1] = 0xefcdab89L;
H[2] = 0x98badcfeL;
H[3] = 0x10325476L;
H[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 uint8_t* dataIn, uint32_t len)
{
MOZ_ASSERT(!mDone, "SHA1Sum can only be used to compute a single hash.");
if (len == 0)
return;
/* Accumulate the byte count. */
unsigned int lenB = static_cast<unsigned int>(size) & 63U;
size += len;
/* Read the data into W and process blocks as they get full. */
unsigned int togo;
if (lenB > 0) {
togo = 64U - lenB;
if (len < togo)
togo = len;
memcpy(u.b + lenB, dataIn, togo);
len -= togo;
dataIn += togo;
lenB = (lenB + togo) & 63U;
if (!lenB)
shaCompress(&H[H2X], u.w);
}
while (len >= 64U) {
len -= 64U;
shaCompress(&H[H2X], reinterpret_cast<const uint32_t*>(dataIn));
dataIn += 64U;
}
if (len > 0)
memcpy(u.b, dataIn, len);
}
/*
* SHA: Generate hash value
*/
void
SHA1Sum::finish(SHA1Sum::Hash& hashOut)
{
MOZ_ASSERT(!mDone, "SHA1Sum can only be used to compute a single hash.");
uint64_t size2 = size;
uint32_t lenB = uint32_t(size2) & 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(size) & 63) == 56);
/* Convert size from bytes to bits. */
size2 <<= 3;
u.w[14] = SHA_HTONL(uint32_t(size2 >> 32));
u.w[15] = SHA_HTONL(uint32_t(size2));
shaCompress(&H[H2X], u.w);
/* Output hash. */
u.w[0] = SHA_HTONL(H[0]);
u.w[1] = SHA_HTONL(H[1]);
u.w[2] = SHA_HTONL(H[2]);
u.w[3] = SHA_HTONL(H[3]);
u.w[4] = SHA_HTONL(H[4]);
memcpy(hashOut, u.w, 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 *X, const uint32_t *inbuf)
{
unsigned A, B, C, D, E;
#define XH(n) X[n - H2X]
#define XW(n) X[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) = SHA_HTONL(inbuf[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;
}
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