jpictl/dns: introduce add command to register new machines

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/wireguard/keys.go

@@ -207,14 +207,20 @@ type KeyPair struct {
 // Validate checks the PublicKey matches the PrivateKey,
 // and sets the PublicKey if missing
 func (kp *KeyPair) Validate() error {
+	keyLen := len(kp.PrivateKey)
+	pubLen := len(kp.PublicKey)
+
 	switch {
-	case kp.PrivateKey.IsZero():
-		// no private key
+	case keyLen != PrivateKeySize:
+		// bad private key
 		return ErrInvalidPrivateKey
-	case kp.PublicKey.IsZero():
+	case pubLen == 0:
 		// no public key, set it
 		kp.PublicKey = kp.PrivateKey.Public()
 		return nil
+	case pubLen != PublicKeySize:
+		// bad public key
+		return ErrInvalidPublicKey
 	case !kp.PrivateKey.Public().Equal(kp.PublicKey):
 		// wrong public key
 		return ErrInvalidPublicKey