feat: add LoadRSACrt

tool/rsa.go

@@ -184,3 +184,72 @@ func RSADecrypt(encryptedBase64 string, cfg *tls.Config) ([]byte, error) {
 
 	return decrypted, nil
 }
+
+func LoadRSACertificate(pubKeyBytes, priKeyBytes []byte) (*rsa.PublicKey, *rsa.PrivateKey, error) {
+	var (
+		err    error
+		pubKey *rsa.PublicKey
+		priKey *rsa.PrivateKey
+	)
+
+	if len(pubKeyBytes) == 0 && len(priKeyBytes) == 0 {
+		return nil, nil, errors.New("both public and private key bytes are empty")
+	}
+
+	if len(pubKeyBytes) > 0 {
+		pubKey, err = parsePublicKey(pubKeyBytes)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	if len(priKeyBytes) > 0 {
+		priKey, err = parsePrivateKey(priKeyBytes)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	return pubKey, priKey, nil
+}
+
+func parsePublicKey(pubKeyBytes []byte) (*rsa.PublicKey, error) {
+	block, _ := pem.Decode(pubKeyBytes)
+	if block == nil {
+		return nil, errors.New("failed to decode public key")
+	}
+
+	pubKey, err := x509.ParsePKIXPublicKey(block.Bytes)
+	if err != nil {
+		return nil, err
+	}
+
+	rsaPubKey, ok := pubKey.(*rsa.PublicKey)
+	if !ok {
+		return nil, errors.New("not an RSA public key")
+	}
+
+	return rsaPubKey, nil
+}
+
+func parsePrivateKey(priKeyBytes []byte) (*rsa.PrivateKey, error) {
+	block, _ := pem.Decode(priKeyBytes)
+	if block == nil {
+		return nil, errors.New("failed to decode private key")
+	}
+
+	priKey, err := x509.ParsePKCS8PrivateKey(block.Bytes)
+	if err != nil {
+		priKey, err = x509.ParsePKCS1PrivateKey(block.Bytes)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	rsaPriKey, ok := priKey.(*rsa.PrivateKey)
+	if !ok {
+		return nil, errors.New("not an RSA private key")
+	}
+
+	return rsaPriKey, nil
+}