added support for none, hopefully in a way you can't use accidentally

none.go

@@ -0,0 +1,54 @@
+package jwt
+
+// Implements the none signing method.  This is required by the spec
+// but you probably should never use it.
+var SigningMethodNone *signingMethodNone
+
+const UnsafeAllowNoneSignatureType unsafeNoneMagicConstant = "none signing method allowed"
+
+var NoneSignatureTypeDisallowedError error
+
+type signingMethodNone struct{}
+type unsafeNoneMagicConstant string
+
+func init() {
+	SigningMethodNone = &signingMethodNone{}
+	NoneSignatureTypeDisallowedError = &ValidationError{
+		"'none' signature type is not allowed",
+		ValidationErrorSignatureInvalid,
+	}
+	RegisterSigningMethod(SigningMethodNone.Alg(), func() SigningMethod {
+		return SigningMethodNone
+	})
+}
+
+func (m *signingMethodNone) Alg() string {
+	return "none"
+}
+
+// Only allow 'none' alg type if UnsafeAllowNoneSignatureType is specified as the key
+func (m *signingMethodNone) Verify(signingString, signature string, key interface{}) (err error) {
+	// Key must be UnsafeAllowNoneSignatureType to prevent accidentally
+	// accepting 'none' signing method
+	if _, ok := key.(unsafeNoneMagicConstant); !ok {
+		return NoneSignatureTypeDisallowedError
+	}
+	// If signing method is none, signature must be an empty string
+	if signature != "" {
+		return &ValidationError{
+			"'none' signing method with non-empty signature",
+			ValidationErrorSignatureInvalid,
+		}
+	}
+
+	// Accept 'none' signing method.
+	return nil
+}
+
+// Only allow 'none' signing if UnsafeAllowNoneSignatureType is specified as the key
+func (m *signingMethodNone) Sign(signingString string, key interface{}) (string, error) {
+	if _, ok := key.(unsafeNoneMagicConstant); ok {
+		return "", nil
+	}
+	return "", NoneSignatureTypeDisallowedError
+}

none_test.go

@@ -0,0 +1,72 @@
+package jwt_test
+
+import (
+	"github.com/dgrijalva/jwt-go"
+	"strings"
+	"testing"
+)
+
+var noneTestData = []struct {
+	name        string
+	tokenString string
+	alg         string
+	key         interface{}
+	claims      map[string]interface{}
+	valid       bool
+}{
+	{
+		"Basic",
+		"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJmb28iOiJiYXIifQ.",
+		"none",
+		jwt.UnsafeAllowNoneSignatureType,
+		map[string]interface{}{"foo": "bar"},
+		true,
+	},
+	{
+		"Basic - no key",
+		"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJmb28iOiJiYXIifQ.",
+		"none",
+		nil,
+		map[string]interface{}{"foo": "bar"},
+		false,
+	},
+	{
+		"Signed",
+		"eyJhbGciOiJSUzM4NCIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIifQ.W-jEzRfBigtCWsinvVVuldiuilzVdU5ty0MvpLaSaqK9PlAWWlDQ1VIQ_qSKzwL5IXaZkvZFJXT3yL3n7OUVu7zCNJzdwznbC8Z-b0z2lYvcklJYi2VOFRcGbJtXUqgjk2oGsiqUMUMOLP70TTefkpsgqDxbRh9CDUfpOJgW-dU7cmgaoswe3wjUAUi6B6G2YEaiuXC0XScQYSYVKIzgKXJV8Zw-7AN_DBUI4GkTpsvQ9fVVjZM9csQiEXhYekyrKu1nu_POpQonGd8yqkIyXPECNmmqH5jH4sFiF67XhD7_JpkvLziBpI-uh86evBUadmHhb9Otqw3uV3NTaXLzJw",
+		"none",
+		jwt.UnsafeAllowNoneSignatureType,
+		map[string]interface{}{"foo": "bar"},
+		false,
+	},
+}
+
+func TestNoneVerify(t *testing.T) {
+	for _, data := range noneTestData {
+		parts := strings.Split(data.tokenString, ".")
+
+		method := jwt.GetSigningMethod(data.alg)
+		err := method.Verify(strings.Join(parts[0:2], "."), parts[2], data.key)
+		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 TestNoneSign(t *testing.T) {
+	for _, data := range noneTestData {
+		if data.valid {
+			parts := strings.Split(data.tokenString, ".")
+			method := jwt.GetSigningMethod(data.alg)
+			sig, err := method.Sign(strings.Join(parts[0:2], "."), data.key)
+			if err != nil {
+				t.Errorf("[%v] Error signing token: %v", data.name, err)
+			}
+			if sig != parts[2] {
+				t.Errorf("[%v] Incorrect signature.\nwas:\n%v\nexpecting:\n%v", data.name, sig, parts[2])
+			}
+		}
+	}
+}