fix: suppress interactive OpenSSL stdin passphrase prompts during mTLS cert loading fallbacks

Author: nbayati

packages/google-auth/google/auth/aio/transport/mtls.py

@@ -54,7 +54,9 @@ def make_client_cert_ssl_context(
         try:
             context = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
             context.load_cert_chain(
-                certfile=cert_path, keyfile=key_path, password=passphrase_val
+                certfile=cert_path,
+                keyfile=key_path,
+                password=passphrase_val or "",
             )
             return context
         except (ssl.SSLError, OSError, IOError, ValueError, RuntimeError) as exc:

packages/google-auth/google/auth/compute_engine/_mtls.py

@@ -120,7 +120,7 @@ def __init__(
         self.ssl_context = ssl.create_default_context()
         self.ssl_context.load_verify_locations(cafile=mds_mtls_config.ca_cert_path)
         self.ssl_context.load_cert_chain(
-            certfile=mds_mtls_config.client_combined_cert_path
+            certfile=mds_mtls_config.client_combined_cert_path, password=""
         )
         super(MdsMtlsAdapter, self).__init__(*args, **kwargs)