TUN-528: Move cloudflared into a separate repo

vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go

@@ -0,0 +1,87 @@
+// 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"
+
+	"golang.org/x/crypto/internal/subtle"
+	"golang.org/x/sys/cpu"
+)
+
+//go:noescape
+func chacha20Poly1305Open(dst []byte, key []uint32, src, ad []byte) bool
+
+//go:noescape
+func chacha20Poly1305Seal(dst []byte, key []uint32, src, ad []byte)
+
+var (
+	useASM  = cpu.X86.HasSSSE3
+	useAVX2 = cpu.X86.HasAVX2 && cpu.X86.HasBMI2
+)
+
+// setupState writes a ChaCha20 input matrix to state. See
+// https://tools.ietf.org/html/rfc7539#section-2.3.
+func setupState(state *[16]uint32, key *[8]uint32, nonce []byte) {
+	state[0] = 0x61707865
+	state[1] = 0x3320646e
+	state[2] = 0x79622d32
+	state[3] = 0x6b206574
+
+	state[4] = key[0]
+	state[5] = key[1]
+	state[6] = key[2]
+	state[7] = key[3]
+	state[8] = key[4]
+	state[9] = key[5]
+	state[10] = key[6]
+	state[11] = key[7]
+
+	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)
+	if subtle.InexactOverlap(out, plaintext) {
+		panic("chacha20poly1305: invalid buffer overlap")
+	}
+	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 subtle.InexactOverlap(out, ciphertext) {
+		panic("chacha20poly1305: invalid buffer overlap")
+	}
+	if !chacha20Poly1305Open(out, state[:], ciphertext, additionalData) {
+		for i := range out {
+			out[i] = 0
+		}
+		return nil, errOpen
+	}
+
+	return ret, nil
+}