diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go')
-rw-r--r-- | vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go b/vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go new file mode 100644 index 0000000..7cd7ad8 --- /dev/null +++ b/vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go @@ -0,0 +1,127 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.7,amd64,!gccgo,!appengine + +package chacha20poly1305 + +import "encoding/binary" + +//go:noescape +func chacha20Poly1305Open(dst []byte, key []uint32, src, ad []byte) bool + +//go:noescape +func chacha20Poly1305Seal(dst []byte, key []uint32, src, ad []byte) + +// cpuid is implemented in chacha20poly1305_amd64.s. +func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32) + +// xgetbv with ecx = 0 is implemented in chacha20poly1305_amd64.s. +func xgetbv() (eax, edx uint32) + +var ( + useASM bool + useAVX2 bool +) + +func init() { + detectCPUFeatures() +} + +// detectCPUFeatures is used to detect if cpu instructions +// used by the functions implemented in assembler in +// chacha20poly1305_amd64.s are supported. +func detectCPUFeatures() { + maxID, _, _, _ := cpuid(0, 0) + if maxID < 1 { + return + } + + _, _, ecx1, _ := cpuid(1, 0) + + haveSSSE3 := isSet(9, ecx1) + useASM = haveSSSE3 + + haveOSXSAVE := isSet(27, ecx1) + + osSupportsAVX := false + // For XGETBV, OSXSAVE bit is required and sufficient. + if haveOSXSAVE { + eax, _ := xgetbv() + // Check if XMM and YMM registers have OS support. + osSupportsAVX = isSet(1, eax) && isSet(2, eax) + } + haveAVX := isSet(28, ecx1) && osSupportsAVX + + if maxID < 7 { + return + } + + _, ebx7, _, _ := cpuid(7, 0) + haveAVX2 := isSet(5, ebx7) && haveAVX + haveBMI2 := isSet(8, ebx7) + + useAVX2 = haveAVX2 && haveBMI2 +} + +// isSet checks if bit at bitpos is set in value. +func isSet(bitpos uint, value uint32) bool { + return value&(1<<bitpos) != 0 +} + +// setupState writes a ChaCha20 input matrix to state. See +// https://tools.ietf.org/html/rfc7539#section-2.3. +func setupState(state *[16]uint32, key *[32]byte, nonce []byte) { + state[0] = 0x61707865 + state[1] = 0x3320646e + state[2] = 0x79622d32 + state[3] = 0x6b206574 + + state[4] = binary.LittleEndian.Uint32(key[:4]) + state[5] = binary.LittleEndian.Uint32(key[4:8]) + state[6] = binary.LittleEndian.Uint32(key[8:12]) + state[7] = binary.LittleEndian.Uint32(key[12:16]) + state[8] = binary.LittleEndian.Uint32(key[16:20]) + state[9] = binary.LittleEndian.Uint32(key[20:24]) + state[10] = binary.LittleEndian.Uint32(key[24:28]) + state[11] = binary.LittleEndian.Uint32(key[28:32]) + + state[12] = 0 + state[13] = binary.LittleEndian.Uint32(nonce[:4]) + state[14] = binary.LittleEndian.Uint32(nonce[4:8]) + state[15] = binary.LittleEndian.Uint32(nonce[8:12]) +} + +func (c *chacha20poly1305) seal(dst, nonce, plaintext, additionalData []byte) []byte { + if !useASM { + return c.sealGeneric(dst, nonce, plaintext, additionalData) + } + + var state [16]uint32 + setupState(&state, &c.key, nonce) + + ret, out := sliceForAppend(dst, len(plaintext)+16) + chacha20Poly1305Seal(out[:], state[:], plaintext, additionalData) + return ret +} + +func (c *chacha20poly1305) open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) { + if !useASM { + return c.openGeneric(dst, nonce, ciphertext, additionalData) + } + + var state [16]uint32 + setupState(&state, &c.key, nonce) + + ciphertext = ciphertext[:len(ciphertext)-16] + ret, out := sliceForAppend(dst, len(ciphertext)) + if !chacha20Poly1305Open(out, state[:], ciphertext, additionalData) { + for i := range out { + out[i] = 0 + } + return nil, errOpen + } + + return ret, nil +} |