outposts: add docker TLS authentication and verification

passbook/outposts/docker_tls.py

@@ -0,0 +1,56 @@
+"""Create Docker TLSConfig from CertificateKeyPair"""
+from pathlib import Path
+from tempfile import gettempdir
+from typing import Optional
+
+from docker.tls import TLSConfig
+
+from passbook.crypto.models import CertificateKeyPair
+
+
+class DockerInlineTLS:
+    """Create Docker TLSConfig from CertificateKeyPair"""
+
+    verification_kp: Optional[CertificateKeyPair]
+    authentication_kp: Optional[CertificateKeyPair]
+
+    def __init__(
+        self,
+        verification_kp: Optional[CertificateKeyPair],
+        authentication_kp: Optional[CertificateKeyPair],
+    ) -> None:
+        self.verification_kp = verification_kp
+        self.authentication_kp = authentication_kp
+
+    def write_file(self, name: str, contents: str) -> str:
+        """Wrapper for mkstemp that uses fdopen"""
+        path = Path(gettempdir(), name)
+        with open(path, "w") as _file:
+            _file.write(contents)
+        return str(path)
+
+    def write(self) -> TLSConfig:
+        """Create TLSConfig with Certificate Keypairs"""
+        # So yes, this is quite ugly. But sadly, there is no clean way to pass
+        # docker-py (which is using requests (which is using urllib3)) a certificate
+        # for verification or authentication as string.
+        # Because we run in docker, and our tmpfs is isolated to us, we can just
+        # write out the certificates and keys to files and use their paths
+        config_args = {}
+        if self.verification_kp:
+            ca_cert_path = self.write_file(
+                f"{self.verification_kp.pk.hex}-cert.pem",
+                self.verification_kp.certificate_data,
+            )
+            config_args["ca_cert"] = ca_cert_path
+        if self.authentication_kp:
+            auth_cert_path = self.write_file(
+                f"{self.authentication_kp.pk.hex}-cert.pem",
+                self.authentication_kp.certificate_data,
+            )
+            auth_key_path = self.write_file(
+                f"{self.authentication_kp.pk.hex}-key.pem",
+                self.authentication_kp.key_data,
+            )
+            config_args["client_cert"] = (auth_cert_path, auth_key_path)
+        return TLSConfig(**config_args)