/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package sha256
import (
"crypto/sha256"
"encoding/binary"
"hash"
"runtime"
"github.com/klauspost/cpuid/v2"
)
// Size - The size of a SHA256 checksum in bytes.
const Size = 32
// BlockSize - The blocksize of SHA256 in bytes.
const BlockSize = 64
const (
chunk = BlockSize
init0 = 0x6A09E667
init1 = 0xBB67AE85
init2 = 0x3C6EF372
init3 = 0xA54FF53A
init4 = 0x510E527F
init5 = 0x9B05688C
init6 = 0x1F83D9AB
init7 = 0x5BE0CD19
)
// digest represents the partial evaluation of a checksum.
type digest struct {
h [8]uint32
x [chunk]byte
nx int
len uint64
}
// Reset digest back to default
func (d *digest) Reset() {
d.h[0] = init0
d.h[1] = init1
d.h[2] = init2
d.h[3] = init3
d.h[4] = init4
d.h[5] = init5
d.h[6] = init6
d.h[7] = init7
d.nx = 0
d.len = 0
}
type blockfuncType int
const (
blockfuncGeneric blockfuncType = iota
blockfuncSha blockfuncType = iota
blockfuncArm blockfuncType = iota
)
var blockfunc blockfuncType
func init() {
blockfunc = blockfuncGeneric
switch {
case hasSHAExtensions():
blockfunc = blockfuncSha
case hasArmSha2():
blockfunc = blockfuncArm
default:
blockfunc = blockfuncGeneric
}
}
var avx512 = cpuid.CPU.Supports(cpuid.AVX512F, cpuid.AVX512DQ, cpuid.AVX512BW, cpuid.AVX512VL)
// hasSHAExtensions return whether the cpu supports SHA extensions.
func hasSHAExtensions() bool {
return cpuid.CPU.Supports(cpuid.SHA, cpuid.SSSE3, cpuid.SSE4) && runtime.GOARCH == "amd64"
}
// New returns a new hash.Hash computing the SHA256 checksum.
func New() hash.Hash {
if blockfunc != blockfuncGeneric {
d := new(digest)
d.Reset()
return d
}
// Fallback to the standard golang implementation
// if no features were found.
return sha256.New()
}
// Sum256 - single caller sha256 helper
func Sum256(data []byte) (result [Size]byte) {
var d digest
d.Reset()
d.Write(data)
result = d.checkSum()
return
}
// Return size of checksum
func (d *digest) Size() int { return Size }
// Return blocksize of checksum
func (d *digest) BlockSize() int { return BlockSize }
// Write to digest
func (d *digest) Write(p []byte) (nn int, err error) {
nn = len(p)
d.len += uint64(nn)
if d.nx > 0 {
n := copy(d.x[d.nx:], p)
d.nx += n
if d.nx == chunk {
block(d, d.x[:])
d.nx = 0
}
p = p[n:]
}
if len(p) >= chunk {
n := len(p) &^ (chunk - 1)
block(d, p[:n])
p = p[n:]
}
if len(p) > 0 {
d.nx = copy(d.x[:], p)
}
return
}
// Return sha256 sum in bytes
func (d *digest) Sum(in []byte) []byte {
// Make a copy of d0 so that caller can keep writing and summing.
d0 := *d
hash := d0.checkSum()
return append(in, hash[:]...)
}
// Intermediate checksum function
func (d *digest) checkSum() (digest [Size]byte) {
n := d.nx
var k [64]byte
copy(k[:], d.x[:n])
k[n] = 0x80
if n >= 56 {
block(d, k[:])
// clear block buffer - go compiles this to optimal 1x xorps + 4x movups
// unfortunately expressing this more succinctly results in much worse code
k[0] = 0
k[1] = 0
k[2] = 0
k[3] = 0
k[4] = 0
k[5] = 0
k[6] = 0
k[7] = 0
k[8] = 0
k[9] = 0
k[10] = 0
k[11] = 0
k[12] = 0
k[13] = 0
k[14] = 0
k[15] = 0
k[16] = 0
k[17] = 0
k[18] = 0
k[19] = 0
k[20] = 0
k[21] = 0
k[22] = 0
k[23] = 0
k[24] = 0
k[25] = 0
k[26] = 0
k[27] = 0
k[28] = 0
k[29] = 0
k[30] = 0
k[31] = 0
k[32] = 0
k[33] = 0
k[34] = 0
k[35] = 0
k[36] = 0
k[37] = 0
k[38] = 0
k[39] = 0
k[40] = 0
k[41] = 0
k[42] = 0
k[43] = 0
k[44] = 0
k[45] = 0
k[46] = 0
k[47] = 0
k[48] = 0
k[49] = 0
k[50] = 0
k[51] = 0
k[52] = 0
k[53] = 0
k[54] = 0
k[55] = 0
k[56] = 0
k[57] = 0
k[58] = 0
k[59] = 0
k[60] = 0
k[61] = 0
k[62] = 0
k[63] = 0
}
binary.BigEndian.PutUint64(k[56:64], uint64(d.len)<<3)
block(d, k[:])
{
const i = 0
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
{
const i = 1
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
{
const i = 2
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
{
const i = 3
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
{
const i = 4
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
{
const i = 5
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
{
const i = 6
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
{
const i = 7
binary.BigEndian.PutUint32(digest[i*4:i*4+4], d.h[i])
}
return
}
func block(dig *digest, p []byte) {
if blockfunc == blockfuncSha {
blockShaGo(dig, p)
} else if blockfunc == blockfuncArm {
blockArmGo(dig, p)
} else if blockfunc == blockfuncGeneric {
blockGeneric(dig, p)
}
}
func blockGeneric(dig *digest, p []byte) {
var w [64]uint32
h0, h1, h2, h3, h4, h5, h6, h7 := dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4], dig.h[5], dig.h[6], dig.h[7]
for len(p) >= chunk {
// Can interlace the computation of w with the
// rounds below if needed for speed.
for i := 0; i < 16; i++ {
j := i * 4
w[i] = uint32(p[j])<<24 | uint32(p[j+1])<<16 | uint32(p[j+2])<<8 | uint32(p[j+3])
}
for i := 16; i < 64; i++ {
v1 := w[i-2]
t1 := (v1>>17 | v1<<(32-17)) ^ (v1>>19 | v1<<(32-19)) ^ (v1 >> 10)
v2 := w[i-15]
t2 := (v2>>7 | v2<<(32-7)) ^ (v2>>18 | v2<<(32-18)) ^ (v2 >> 3)
w[i] = t1 + w[i-7] + t2 + w[i-16]
}
a, b, c, d, e, f, g, h := h0, h1, h2, h3, h4, h5, h6, h7
for i := 0; i < 64; i++ {
t1 := h + ((e>>6 | e<<(32-6)) ^ (e>>11 | e<<(32-11)) ^ (e>>25 | e<<(32-25))) + ((e & f) ^ (^e & g)) + _K[i] + w[i]
t2 := ((a>>2 | a<<(32-2)) ^ (a>>13 | a<<(32-13)) ^ (a>>22 | a<<(32-22))) + ((a & b) ^ (a & c) ^ (b & c))
h = g
g = f
f = e
e = d + t1
d = c
c = b
b = a
a = t1 + t2
}
h0 += a
h1 += b
h2 += c
h3 += d
h4 += e
h5 += f
h6 += g
h7 += h
p = p[chunk:]
}
dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4], dig.h[5], dig.h[6], dig.h[7] = h0, h1, h2, h3, h4, h5, h6, h7
}
var _K = []uint32{
0x428a2f98,
0x71374491,
0xb5c0fbcf,
0xe9b5dba5,
0x3956c25b,
0x59f111f1,
0x923f82a4,
0xab1c5ed5,
0xd807aa98,
0x12835b01,
0x243185be,
0x550c7dc3,
0x72be5d74,
0x80deb1fe,
0x9bdc06a7,
0xc19bf174,
0xe49b69c1,
0xefbe4786,
0x0fc19dc6,
0x240ca1cc,
0x2de92c6f,
0x4a7484aa,
0x5cb0a9dc,
0x76f988da,
0x983e5152,
0xa831c66d,
0xb00327c8,
0xbf597fc7,
0xc6e00bf3,
0xd5a79147,
0x06ca6351,
0x14292967,
0x27b70a85,
0x2e1b2138,
0x4d2c6dfc,
0x53380d13,
0x650a7354,
0x766a0abb,
0x81c2c92e,
0x92722c85,
0xa2bfe8a1,
0xa81a664b,
0xc24b8b70,
0xc76c51a3,
0xd192e819,
0xd6990624,
0xf40e3585,
0x106aa070,
0x19a4c116,
0x1e376c08,
0x2748774c,
0x34b0bcb5,
0x391c0cb3,
0x4ed8aa4a,
0x5b9cca4f,
0x682e6ff3,
0x748f82ee,
0x78a5636f,
0x84c87814,
0x8cc70208,
0x90befffa,
0xa4506ceb,
0xbef9a3f7,
0xc67178f2,
}