Allow marshaling/unmarshaling zero value keys

go/nebula/certificate.go

@@ -2,6 +2,7 @@ package nebula
 
 import (
 	"fmt"
+	"reflect"
 
 	"github.com/slackhq/nebula/cert"
 )
@@ -37,14 +38,22 @@ func (c Certificate) Unwrap() *cert.NebulaCertificate {
 
 // MarshalText implements the encoding.TextMarshaler interface.
 func (c Certificate) MarshalText() ([]byte, error) {
+	if reflect.DeepEqual(c, Certificate{}) {
+		return []byte(""), nil
+	}
 	return c.inner.MarshalToPEM()
 }
 
 // UnmarshalText implements the encoding.TextUnmarshaler interface.
 func (c *Certificate) UnmarshalText(b []byte) error {
+	if len(b) == 0 {
+		*c = Certificate{}
+		return nil
+	}
+
 	nebCrt, _, err := cert.UnmarshalNebulaCertificateFromPEM(b)
 	if err != nil {
-		return err
+		return fmt.Errorf("unmarshaling nebula certificate from PEM: %w", err)
 	}
 	c.inner = *nebCrt
 	return nil

go/nebula/encrypting_key.go

@@ -21,19 +21,31 @@ type EncryptingPublicKey struct{ inner *ecdh.PublicKey }
 
 // MarshalText implements the encoding.TextMarshaler interface.
 func (pk EncryptingPublicKey) MarshalText() ([]byte, error) {
-	return encodeWithPrefix(encPubKeyPrefix, pk.inner.Bytes()), nil
+	if pk == (EncryptingPublicKey{}) {
+		return []byte(""), nil
+	}
+	return encodeWithPrefix(encPubKeyPrefix, pk.Bytes()), nil
 }
 
-// Bytes returns the raw bytes of the EncryptingPublicKey.
+// Bytes returns the raw bytes of the EncryptingPublicKey, or nil if it is the
+// zero value.
 func (k EncryptingPublicKey) Bytes() []byte {
+	if k == (EncryptingPublicKey{}) {
+		return nil
+	}
 	return k.inner.Bytes()
 }
 
 // UnmarshalText implements the encoding.TextUnmarshaler interface.
 func (pk *EncryptingPublicKey) UnmarshalText(b []byte) error {
+	if len(b) == 0 {
+		*pk = EncryptingPublicKey{}
+		return nil
+	}
+
 	b, err := decodeWithPrefix(encPubKeyPrefix, b)
 	if err != nil {
-		return fmt.Errorf("unmarshaling: %w", err)
+		return fmt.Errorf("unmarshaling encrypting public key: %w", err)
 	}
 
 	if pk.inner, err = x25519.NewPublicKey(b); err != nil {
@@ -48,7 +60,7 @@ func (pk *EncryptingPublicKey) UnmarshalText(b []byte) error {
 func (pk *EncryptingPublicKey) UnmarshalNebulaPEM(b []byte) error {
 	b, _, err := cert.UnmarshalX25519PublicKey(b)
 	if err != nil {
-		return fmt.Errorf("unmarshaling: %w", err)
+		return fmt.Errorf("unmarshaling nebula PEM as encrypting public key: %w", err)
 	}
 
 	if pk.inner, err = x25519.NewPublicKey(b); err != nil {
@@ -86,19 +98,31 @@ func (k EncryptingPrivateKey) PublicKey() EncryptingPublicKey {
 
 // MarshalText implements the encoding.TextMarshaler interface.
 func (k EncryptingPrivateKey) MarshalText() ([]byte, error) {
-	return encodeWithPrefix(encPrivKeyPrefix, k.inner.Bytes()), nil
+	if k == (EncryptingPrivateKey{}) {
+		return []byte(""), nil
+	}
+	return encodeWithPrefix(encPrivKeyPrefix, k.Bytes()), nil
 }
 
-// Bytes returns the raw bytes of the EncryptingPrivateKey.
+// Bytes returns the raw bytes of the EncryptingPrivateKey, or nil if it is the
+// zero value.
 func (k EncryptingPrivateKey) Bytes() []byte {
+	if k == (EncryptingPrivateKey{}) {
+		return nil
+	}
 	return k.inner.Bytes()
 }
 
 // UnmarshalText implements the encoding.TextUnmarshaler interface.
 func (k *EncryptingPrivateKey) UnmarshalText(b []byte) error {
+	if len(b) == 0 {
+		*k = EncryptingPrivateKey{}
+		return nil
+	}
+
 	b, err := decodeWithPrefix(encPrivKeyPrefix, b)
 	if err != nil {
-		return fmt.Errorf("unmarshaling: %w", err)
+		return fmt.Errorf("unmarshaling encrypting private key: %w", err)
 	}
 
 	if k.inner, err = x25519.NewPrivateKey(b); err != nil {

go/nebula/signed.go

@@ -1,6 +1,7 @@
 package nebula
 
 import (
+	"bytes"
 	"crypto"
 	"crypto/ed25519"
 	"crypto/rand"
@@ -47,13 +48,23 @@ func Sign[T any](v T, k SigningPrivateKey) (Signed[T], error) {
 	return json.Marshal(signed[T]{Signature: sig, Body: json.RawMessage(b)})
 }
 
+var jsonNull = []byte("null")
+
 // MarshalJSON implements the json.Marshaler interface.
 func (s Signed[T]) MarshalJSON() ([]byte, error) {
+	if s == nil {
+		return jsonNull, nil
+	}
 	return []byte(s), nil
 }
 
 // UnmarshalJSON implements the json.Unmarshaler interface.
 func (s *Signed[T]) UnmarshalJSON(b []byte) error {
+	if bytes.Equal(b, jsonNull) {
+		*s = nil
+		return nil
+	}
+
 	*s = b
 	return nil
 }

go/nebula/signed_test.go

@@ -34,7 +34,7 @@ func TestSigned(t *testing.T) {
 
 	_, err = signedB.Unwrap(hostPubCredsB.SigningKey)
 	if !errors.Is(err, ErrInvalidSignature) {
-		t.Fatalf("expected ErrInvalidSignature but got %v", err)
+		t.Fatalf("expected ErrInvalidSignature but got: %v", err)
 	}
 
 	b, err := signedB.Unwrap(hostPubCredsA.SigningKey)

go/nebula/signing_key.go

@@ -17,14 +17,22 @@ type SigningPrivateKey ed25519.PrivateKey
 
 // MarshalText implements the encoding.TextMarshaler interface.
 func (k SigningPrivateKey) MarshalText() ([]byte, error) {
+	if k == nil {
+		return []byte(""), nil
+	}
 	return encodeWithPrefix(sigPrivKeyPrefix, k), nil
 }
 
 // UnmarshalText implements the encoding.TextUnmarshaler interface.
 func (k *SigningPrivateKey) UnmarshalText(b []byte) error {
+	if len(b) == 0 {
+		*k = SigningPrivateKey{}
+		return nil
+	}
+
 	b, err := decodeWithPrefix(sigPrivKeyPrefix, b)
 	if err != nil {
-		return fmt.Errorf("unmarshaling: %w", err)
+		return fmt.Errorf("unmarshaling signing private key: %w", err)
 	}
 
 	*k = SigningPrivateKey(b)
@@ -45,14 +53,22 @@ type SigningPublicKey ed25519.PublicKey
 
 // MarshalText implements the encoding.TextMarshaler interface.
 func (pk SigningPublicKey) MarshalText() ([]byte, error) {
+	if pk == nil {
+		return []byte(""), nil
+	}
 	return encodeWithPrefix(sigPubKeyPrefix, pk), nil
 }
 
 // UnmarshalText implements the encoding.TextUnmarshaler interface.
 func (pk *SigningPublicKey) UnmarshalText(b []byte) error {
+	if len(b) == 0 {
+		*pk = SigningPublicKey{}
+		return nil
+	}
+
 	b, err := decodeWithPrefix(sigPubKeyPrefix, b)
 	if err != nil {
-		return fmt.Errorf("unmarshaling: %w", err)
+		return fmt.Errorf("unmarshaling signing public key: %w", err)
 	}
 
 	*pk = SigningPublicKey(b)