Bryan C. Mills
f7b00557c8
It is unclear whether unaligned reads should be allowed, or if they are even actually a good idea here. However, while we figure that out, we should un-break 'go test -race' for users of this package. Updates golang/go#37644 Updates golang/go#37298 Updates golang/go#37715 Updates golang/go#34972 Updates golang/go#35128 Change-Id: I088f5703023e4f05ee274a6753e925973f12ac1b Reviewed-on: https://go-review.googlesource.com/c/crypto/+/222855 Run-TryBot: Bryan C. Mills <bcmills@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
77 lines
1.6 KiB
Go
77 lines
1.6 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build amd64 386 ppc64le
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// +build !appengine
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package sha3
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import "unsafe"
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// A storageBuf is an aligned array of maxRate bytes.
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type storageBuf [maxRate / 8]uint64
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func (b *storageBuf) asBytes() *[maxRate]byte {
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return (*[maxRate]byte)(unsafe.Pointer(b))
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}
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//go:nocheckptr
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//
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// xorInUnaligned intentionally reads the input buffer as an unaligned slice of
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// integers. The language spec is not clear on whether that is allowed.
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// See:
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// https://golang.org/issue/37644
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// https://golang.org/issue/37298
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// https://golang.org/issue/35381
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// xorInUnaligned uses unaligned reads and writes to update d.a to contain d.a
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// XOR buf.
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func xorInUnaligned(d *state, buf []byte) {
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n := len(buf)
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bw := (*[maxRate / 8]uint64)(unsafe.Pointer(&buf[0]))[: n/8 : n/8]
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if n >= 72 {
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d.a[0] ^= bw[0]
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d.a[1] ^= bw[1]
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d.a[2] ^= bw[2]
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d.a[3] ^= bw[3]
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d.a[4] ^= bw[4]
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d.a[5] ^= bw[5]
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d.a[6] ^= bw[6]
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d.a[7] ^= bw[7]
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d.a[8] ^= bw[8]
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}
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if n >= 104 {
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d.a[9] ^= bw[9]
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d.a[10] ^= bw[10]
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d.a[11] ^= bw[11]
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d.a[12] ^= bw[12]
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}
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if n >= 136 {
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d.a[13] ^= bw[13]
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d.a[14] ^= bw[14]
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d.a[15] ^= bw[15]
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d.a[16] ^= bw[16]
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}
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if n >= 144 {
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d.a[17] ^= bw[17]
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}
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if n >= 168 {
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d.a[18] ^= bw[18]
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d.a[19] ^= bw[19]
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d.a[20] ^= bw[20]
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}
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}
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func copyOutUnaligned(d *state, buf []byte) {
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ab := (*[maxRate]uint8)(unsafe.Pointer(&d.a[0]))
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copy(buf, ab[:])
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}
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var (
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xorIn = xorInUnaligned
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copyOut = copyOutUnaligned
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)
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const xorImplementationUnaligned = "unaligned"
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