crypto/ed25519: promote from golang.org/x/crypto/ed25519

The crypto/tls and crypto/x509 APIs leak PublicKey and PrivateKey types,
so in order to add support for Ed25519 certificates we need the ed25519
package in the stdlib.

It's also a primitive that's reasonable to use directly in applications,
as it is a modern, safe and fast signing algorithm, for which there
aren't higher level APIs. (The nacl/sign API is limiting in that it
repeats the message.)

A few docs changes will come in a follow-up, and a CL will land on
golang.org/x/crypto/ed25519 to make it a type alias wrapper on Go 1.13+.

Updates #25355

Change-Id: I057f20cc7d1aca2b95c29ce73eb03c3b237e413f
Reviewed-on: https://go-review.googlesource.com/c/go/+/174945
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>

misc/nacl/testzip.proto

@@ -97,6 +97,9 @@ go	src=..
 				+
 			zlib
 		crypto
+			ed25519
+				testdata
+					+
 			rsa
 				testdata
 					+

src/cmd/go/internal/note/note.go

@@ -183,6 +183,7 @@ package note
 
 import (
 	"bytes"
+	"crypto/ed25519"
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/binary"
@@ -193,8 +194,6 @@ import (
 	"strings"
 	"unicode"
 	"unicode/utf8"
-
-	"golang.org/x/crypto/ed25519"
 )
 
 // A Verifier verifies messages signed with a specific key.

src/cmd/go/internal/note/note_test.go

@@ -5,13 +5,12 @@
 package note
 
 import (
+	"crypto/ed25519"
 	"crypto/rand"
 	"errors"
 	"strings"
 	"testing"
 	"testing/iotest"
-
-	"golang.org/x/crypto/ed25519"
 )
 
 func TestNewVerifier(t *testing.T) {
@@ -165,7 +164,7 @@ func TestFromEd25519(t *testing.T) {
 }
 
 // newSignerFromEd25519Seed constructs a new signer from a verifier name and a
-// golang.org/x/crypto/ed25519 private key seed.
+// crypto/ed25519 private key seed.
 func newSignerFromEd25519Seed(name string, seed []byte) (Signer, error) {
 	if len(seed) != ed25519.SeedSize {
 		return nil, errors.New("invalid seed size")

src/cmd/vendor/modules.txt

@@ -22,8 +22,6 @@ golang.org/x/arch/arm64/arm64asm
 golang.org/x/arch/ppc64/ppc64asm
 golang.org/x/arch/x86/x86asm
 # golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c
-golang.org/x/crypto/ed25519
-golang.org/x/crypto/ed25519/internal/edwards25519
 golang.org/x/crypto/ssh/terminal
 # golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82
 golang.org/x/sys/unix

src/cmd/vendor/golang.org/x/crypto/ed25519/ed25519.go → src/crypto/ed25519/ed25519.go

@@ -18,13 +18,12 @@ package ed25519
 import (
 	"bytes"
 	"crypto"
+	"crypto/ed25519/internal/edwards25519"
 	cryptorand "crypto/rand"
 	"crypto/sha512"
 	"errors"
 	"io"
 	"strconv"
-
-	"golang.org/x/crypto/ed25519/internal/edwards25519"
 )
 
 const (

src/crypto/ed25519/ed25519_test.go

+// 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.
+
+package ed25519
+
+import (
+	"bufio"
+	"bytes"
+	"compress/gzip"
+	"crypto"
+	"crypto/ed25519/internal/edwards25519"
+	"crypto/rand"
+	"encoding/hex"
+	"os"
+	"strings"
+	"testing"
+)
+
+type zeroReader struct{}
+
+func (zeroReader) Read(buf []byte) (int, error) {
+	for i := range buf {
+		buf[i] = 0
+	}
+	return len(buf), nil
+}
+
+func TestUnmarshalMarshal(t *testing.T) {
+	pub, _, _ := GenerateKey(rand.Reader)
+
+	var A edwards25519.ExtendedGroupElement
+	var pubBytes [32]byte
+	copy(pubBytes[:], pub)
+	if !A.FromBytes(&pubBytes) {
+		t.Fatalf("ExtendedGroupElement.FromBytes failed")
+	}
+
+	var pub2 [32]byte
+	A.ToBytes(&pub2)
+
+	if pubBytes != pub2 {
+		t.Errorf("FromBytes(%v)->ToBytes does not round-trip, got %x\n", pubBytes, pub2)
+	}
+}
+
+func TestSignVerify(t *testing.T) {
+	var zero zeroReader
+	public, private, _ := GenerateKey(zero)
+
+	message := []byte("test message")
+	sig := Sign(private, message)
+	if !Verify(public, message, sig) {
+		t.Errorf("valid signature rejected")
+	}
+
+	wrongMessage := []byte("wrong message")
+	if Verify(public, wrongMessage, sig) {
+		t.Errorf("signature of different message accepted")
+	}
+}
+
+func TestCryptoSigner(t *testing.T) {
+	var zero zeroReader
+	public, private, _ := GenerateKey(zero)
+
+	signer := crypto.Signer(private)
+
+	publicInterface := signer.Public()
+	public2, ok := publicInterface.(PublicKey)
+	if !ok {
+		t.Fatalf("expected PublicKey from Public() but got %T", publicInterface)
+	}
+
+	if !bytes.Equal(public, public2) {
+		t.Errorf("public keys do not match: original:%x vs Public():%x", public, public2)
+	}
+
+	message := []byte("message")
+	var noHash crypto.Hash
+	signature, err := signer.Sign(zero, message, noHash)
+	if err != nil {
+		t.Fatalf("error from Sign(): %s", err)
+	}
+
+	if !Verify(public, message, signature) {
+		t.Errorf("Verify failed on signature from Sign()")
+	}
+}
+
+func TestGolden(t *testing.T) {
+	// sign.input.gz is a selection of test cases from
+	// https://ed25519.cr.yp.to/python/sign.input
+	testDataZ, err := os.Open("testdata/sign.input.gz")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer testDataZ.Close()
+	testData, err := gzip.NewReader(testDataZ)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer testData.Close()
+
+	scanner := bufio.NewScanner(testData)
+	lineNo := 0
+
+	for scanner.Scan() {
+		lineNo++
+
+		line := scanner.Text()
+		parts := strings.Split(line, ":")
+		if len(parts) != 5 {
+			t.Fatalf("bad number of parts on line %d", lineNo)
+		}
+
+		privBytes, _ := hex.DecodeString(parts[0])
+		pubKey, _ := hex.DecodeString(parts[1])
+		msg, _ := hex.DecodeString(parts[2])
+		sig, _ := hex.DecodeString(parts[3])
+		// The signatures in the test vectors also include the message
+		// at the end, but we just want R and S.
+		sig = sig[:SignatureSize]
+
+		if l := len(pubKey); l != PublicKeySize {
+			t.Fatalf("bad public key length on line %d: got %d bytes", lineNo, l)
+		}
+
+		var priv [PrivateKeySize]byte
+		copy(priv[:], privBytes)
+		copy(priv[32:], pubKey)
+
+		sig2 := Sign(priv[:], msg)
+		if !bytes.Equal(sig, sig2[:]) {
+			t.Errorf("different signature result on line %d: %x vs %x", lineNo, sig, sig2)
+		}
+
+		if !Verify(pubKey, msg, sig2) {
+			t.Errorf("signature failed to verify on line %d", lineNo)
+		}
+
+		priv2 := NewKeyFromSeed(priv[:32])
+		if !bytes.Equal(priv[:], priv2) {
+			t.Errorf("recreating key pair gave different private key on line %d: %x vs %x", lineNo, priv[:], priv2)
+		}
+
+		if pubKey2 := priv2.Public().(PublicKey); !bytes.Equal(pubKey, pubKey2) {
+			t.Errorf("recreating key pair gave different public key on line %d: %x vs %x", lineNo, pubKey, pubKey2)
+		}
+
+		if seed := priv2.Seed(); !bytes.Equal(priv[:32], seed) {
+			t.Errorf("recreating key pair gave different seed on line %d: %x vs %x", lineNo, priv[:32], seed)
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		t.Fatalf("error reading test data: %s", err)
+	}
+}
+
+func TestMalleability(t *testing.T) {
+	// https://tools.ietf.org/html/rfc8032#section-5.1.7 adds an additional test
+	// that s be in [0, order). This prevents someone from adding a multiple of
+	// order to s and obtaining a second valid signature for the same message.
+	msg := []byte{0x54, 0x65, 0x73, 0x74}
+	sig := []byte{
+		0x7c, 0x38, 0xe0, 0x26, 0xf2, 0x9e, 0x14, 0xaa, 0xbd, 0x05, 0x9a,
+		0x0f, 0x2d, 0xb8, 0xb0, 0xcd, 0x78, 0x30, 0x40, 0x60, 0x9a, 0x8b,
+		0xe6, 0x84, 0xdb, 0x12, 0xf8, 0x2a, 0x27, 0x77, 0x4a, 0xb0, 0x67,
+		0x65, 0x4b, 0xce, 0x38, 0x32, 0xc2, 0xd7, 0x6f, 0x8f, 0x6f, 0x5d,
+		0xaf, 0xc0, 0x8d, 0x93, 0x39, 0xd4, 0xee, 0xf6, 0x76, 0x57, 0x33,
+		0x36, 0xa5, 0xc5, 0x1e, 0xb6, 0xf9, 0x46, 0xb3, 0x1d,
+	}
+	publicKey := []byte{
+		0x7d, 0x4d, 0x0e, 0x7f, 0x61, 0x53, 0xa6, 0x9b, 0x62, 0x42, 0xb5,
+		0x22, 0xab, 0xbe, 0xe6, 0x85, 0xfd, 0xa4, 0x42, 0x0f, 0x88, 0x34,
+		0xb1, 0x08, 0xc3, 0xbd, 0xae, 0x36, 0x9e, 0xf5, 0x49, 0xfa,
+	}
+
+	if Verify(publicKey, msg, sig) {
+		t.Fatal("non-canonical signature accepted")
+	}
+}
+
+func BenchmarkKeyGeneration(b *testing.B) {
+	var zero zeroReader
+	for i := 0; i < b.N; i++ {
+		if _, _, err := GenerateKey(zero); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkSigning(b *testing.B) {
+	var zero zeroReader
+	_, priv, err := GenerateKey(zero)
+	if err != nil {
+		b.Fatal(err)
+	}
+	message := []byte("Hello, world!")
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Sign(priv, message)
+	}
+}
+
+func BenchmarkVerification(b *testing.B) {
+	var zero zeroReader
+	pub, priv, err := GenerateKey(zero)
+	if err != nil {
+		b.Fatal(err)
+	}
+	message := []byte("Hello, world!")
+	signature := Sign(priv, message)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Verify(pub, message, signature)
+	}
+}

src/go/build/deps_test.go

@@ -375,6 +375,10 @@ var pkgDeps = map[string][]string{
 	// math/big, which imports fmt.
 	"crypto/rand": {"L4", "CRYPTO", "OS", "math/big", "syscall", "syscall/js", "internal/syscall/unix"},
 
+	// Not part of CRYPTO because it imports crypto/rand and crypto/sha512.
+	"crypto/ed25519":                       {"L3", "CRYPTO", "crypto/rand", "crypto/ed25519/internal/edwards25519"},
+	"crypto/ed25519/internal/edwards25519": {"encoding/binary"},
+
 	// Mathematical crypto: dependencies on fmt (L4) and math/big.
 	// We could avoid some of the fmt, but math/big imports fmt anyway.
 	"crypto/dsa":      {"L4", "CRYPTO", "math/big"},