add ed25519 support (#36)

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

cmd/jwt/app.go

@@ -136,6 +136,8 @@ func verifyToken() error {
 			return jwt.ParseECPublicKeyFromPEM(data)
 		} else if isRs() {
 			return jwt.ParseRSAPublicKeyFromPEM(data)
+		} else if isEd() {
+			return jwt.ParseEdPublicKeyFromPEM(data)
 		}
 		return data, nil
 	})
@@ -229,6 +231,15 @@ func signToken() error {
 				return err
 			}
 		}
+	} else if isEd() {
+		if k, ok := key.([]byte); !ok {
+			return fmt.Errorf("Couldn't convert key data to key")
+		} else {
+			key, err = jwt.ParseEdPrivateKeyFromPEM(k)
+			if err != nil {
+				return err
+			}
+		}
 	}
 
 	if out, err := token.SignedString(key); err == nil {
@@ -280,3 +291,7 @@ func isEs() bool {
 func isRs() bool {
 	return strings.HasPrefix(*flagAlg, "RS") || strings.HasPrefix(*flagAlg, "PS")
 }
+
+func isEd() bool {
+	return strings.HasPrefix(strings.ToUpper(*flagAlg), "Ed")
+}

ed25519.go

@@ -0,0 +1,81 @@
+package jwt
+
+import (
+	"errors"
+
+	"crypto/ed25519"
+)
+
+var (
+	ErrEd25519Verification = errors.New("ed25519: verification error")
+)
+
+// Implements the EdDSA family
+// Expects ed25519.PrivateKey for signing and ed25519.PublicKey for verification
+type SigningMethodEd25519 struct{}
+
+// Specific instance for EdDSA
+var (
+	SigningMethodEdDSA *SigningMethodEd25519
+)
+
+func init() {
+	SigningMethodEdDSA = &SigningMethodEd25519{}
+	RegisterSigningMethod(SigningMethodEdDSA.Alg(), func() SigningMethod {
+		return SigningMethodEdDSA
+	})
+}
+
+func (m *SigningMethodEd25519) Alg() string {
+	return "EdDSA"
+}
+
+// Implements the Verify method from SigningMethod
+// For this verify method, key must be an ed25519.PublicKey
+func (m *SigningMethodEd25519) Verify(signingString, signature string, key interface{}) error {
+	var err error
+	var ed25519Key ed25519.PublicKey
+	var ok bool
+
+	if ed25519Key, ok = key.(ed25519.PublicKey); !ok {
+		return ErrInvalidKeyType
+	}
+
+	if len(ed25519Key) != ed25519.PublicKeySize {
+		return ErrInvalidKey
+	}
+
+	// Decode the signature
+	var sig []byte
+	if sig, err = DecodeSegment(signature); err != nil {
+		return err
+	}
+
+	// Verify the signature
+	if !ed25519.Verify(ed25519Key, []byte(signingString), sig) {
+		return ErrEd25519Verification
+	}
+
+	return nil
+}
+
+// Implements the Sign method from SigningMethod
+// For this signing method, key must be an ed25519.PrivateKey
+func (m *SigningMethodEd25519) Sign(signingString string, key interface{}) (string, error) {
+	var ed25519Key ed25519.PrivateKey
+	var ok bool
+
+	if ed25519Key, ok = key.(ed25519.PrivateKey); !ok {
+		return "", ErrInvalidKeyType
+	}
+
+	// ed25519.Sign panics if private key not equal to ed25519.PrivateKeySize
+	// this allows to avoid recover usage
+	if len(ed25519Key) != ed25519.PrivateKeySize {
+		return "", ErrInvalidKey
+	}
+
+	// Sign the string and return the encoded result
+	sig := ed25519.Sign(ed25519Key, []byte(signingString))
+	return EncodeSegment(sig), nil
+}

ed25519_test.go

@@ -0,0 +1,84 @@
+package jwt_test
+
+import (
+	"io/ioutil"
+	"strings"
+	"testing"
+
+	"github.com/golang-jwt/jwt"
+)
+
+var ed25519TestData = []struct {
+	name        string
+	keys        map[string]string
+	tokenString string
+	alg         string
+	claims      map[string]interface{}
+	valid       bool
+}{
+	{
+		"Basic Ed25519",
+		map[string]string{"private": "test/ed25519-private.pem", "public": "test/ed25519-public.pem"},
+		"eyJhbGciOiJFRDI1NTE5IiwidHlwIjoiSldUIn0.eyJmb28iOiJiYXIifQ.ESuVzZq1cECrt9Od_gLPVG-_6uRP_8Nq-ajx6CtmlDqRJZqdejro2ilkqaQgSL-siE_3JMTUW7UwAorLaTyFCw",
+		"EdDSA",
+		map[string]interface{}{"foo": "bar"},
+		true,
+	},
+	{
+		"Basic Ed25519",
+		map[string]string{"private": "test/ed25519-private.pem", "public": "test/ed25519-public.pem"},
+		"eyJhbGciOiJFRDI1NTE5IiwidHlwIjoiSldUIn0.eyJmb28iOiJiYXoifQ.ESuVzZq1cECrt9Od_gLPVG-_6uRP_8Nq-ajx6CtmlDqRJZqdejro2ilkqaQgSL-siE_3JMTUW7UwAorLaTyFCw",
+		"EdDSA",
+		map[string]interface{}{"foo": "bar"},
+		false,
+	},
+}
+
+func TestEd25519Verify(t *testing.T) {
+	for _, data := range ed25519TestData {
+		var err error
+
+		key, _ := ioutil.ReadFile(data.keys["public"])
+
+		ed25519Key, err := jwt.ParseEdPublicKeyFromPEM(key)
+		if err != nil {
+			t.Errorf("Unable to parse Ed25519 public key: %v", err)
+		}
+
+		parts := strings.Split(data.tokenString, ".")
+
+		method := jwt.GetSigningMethod(data.alg)
+
+		err = method.Verify(strings.Join(parts[0:2], "."), parts[2], ed25519Key)
+		if data.valid && err != nil {
+			t.Errorf("[%v] Error while verifying key: %v", data.name, err)
+		}
+		if !data.valid && err == nil {
+			t.Errorf("[%v] Invalid key passed validation", data.name)
+		}
+	}
+}
+
+func TestEd25519Sign(t *testing.T) {
+	for _, data := range ed25519TestData {
+		var err error
+		key, _ := ioutil.ReadFile(data.keys["private"])
+
+		ed25519Key, err := jwt.ParseEdPrivateKeyFromPEM(key)
+		if err != nil {
+			t.Errorf("Unable to parse Ed25519 private key: %v", err)
+		}
+
+		parts := strings.Split(data.tokenString, ".")
+
+		method := jwt.GetSigningMethod(data.alg)
+
+		sig, err := method.Sign(strings.Join(parts[0:2], "."), ed25519Key)
+		if err != nil {
+			t.Errorf("[%v] Error signing token: %v", data.name, err)
+		}
+		if sig == parts[2] && !data.valid {
+			t.Errorf("[%v] Identical signatures\nbefore:\n%v\nafter:\n%v", data.name, parts[2], sig)
+		}
+	}
+}

ed25519_utils.go

@@ -0,0 +1,64 @@
+package jwt
+
+import (
+	"crypto"
+	"crypto/ed25519"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+)
+
+var (
+	ErrNotEdPrivateKey = errors.New("Key is not a valid Ed25519 private key")
+	ErrNotEdPublicKey  = errors.New("Key is not a valid Ed25519 public key")
+)
+
+// Parse PEM-encoded Edwards curve private key
+func ParseEdPrivateKeyFromPEM(key []byte) (crypto.PrivateKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	// Parse the key
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKCS8PrivateKey(block.Bytes); err != nil {
+		return nil, err
+	}
+
+	var pkey ed25519.PrivateKey
+	var ok bool
+	if pkey, ok = parsedKey.(ed25519.PrivateKey); !ok {
+		return nil, ErrNotEdPrivateKey
+	}
+
+	return pkey, nil
+}
+
+// Parse PEM-encoded Edwards curve public key
+func ParseEdPublicKeyFromPEM(key []byte) (crypto.PublicKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	// Parse the key
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
+		return nil, err
+	}
+
+	var pkey ed25519.PublicKey
+	var ok bool
+	if pkey, ok = parsedKey.(ed25519.PublicKey); !ok {
+		return nil, ErrNotEdPublicKey
+	}
+
+	return pkey, nil
+}

test/ed25519-private.pem

@@ -0,0 +1,3 @@
+-----BEGIN PRIVATE KEY-----
+MC4CAQAwBQYDK2VwBCIEIEFMEZrmlYxczXKFxIlNvNGR5JQvDhTkLovJYxwQd3ua
+-----END PRIVATE KEY-----

test/ed25519-public.pem

@@ -0,0 +1,3 @@
+-----BEGIN PUBLIC KEY-----
+MCowBQYDK2VwAyEAWH7z6hpYqvPns2i4n9yymwvB3APhi4LyQ7iHOT6crtE=
+-----END PUBLIC KEY-----