crypto: add additional validation before importing a certificate

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

authentik/crypto/models.py

@@ -11,10 +11,13 @@ from cryptography.hazmat.primitives.serialization import load_pem_private_key
 from cryptography.x509 import Certificate, load_pem_x509_certificate
 from django.db import models
 from django.utils.translation import gettext_lazy as _
+from structlog.stdlib import get_logger
 
 from authentik.lib.models import CreatedUpdatedModel
 from authentik.managed.models import ManagedModel
 
+LOGGER = get_logger()
+
 
 class CertificateKeyPair(ManagedModel, CreatedUpdatedModel):
     """CertificateKeyPair that can be used for signing or encrypting if `key_data`
@@ -62,7 +65,8 @@ class CertificateKeyPair(ManagedModel, CreatedUpdatedModel):
                     password=None,
                     backend=default_backend(),
                 )
-            except ValueError:
+            except ValueError as exc:
+                LOGGER.warning(exc)
                 return None
         return self._private_key
 

authentik/crypto/tasks.py

@@ -2,6 +2,9 @@
 from glob import glob
 from pathlib import Path
 
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives.serialization import load_pem_private_key
+from cryptography.x509.base import load_pem_x509_certificate
 from django.utils.translation import gettext_lazy as _
 from structlog.stdlib import get_logger
 
@@ -20,6 +23,22 @@ LOGGER = get_logger()
 MANAGED_DISCOVERED = "goauthentik.io/crypto/discovered/%s"
 
 
+def ensure_private_key_valid(body: str):
+    """Attempt loading of an RSA Private key without password"""
+    load_pem_private_key(
+        str.encode("\n".join([x.strip() for x in body.split("\n")])),
+        password=None,
+        backend=default_backend(),
+    )
+    return body
+
+
+def ensure_certificate_valid(body: str):
+    """Attempt loading of a PEM-encoded certificate"""
+    load_pem_x509_certificate(body.encode("utf-8"), default_backend())
+    return body
+
+
 @CELERY_APP.task(bind=True, base=MonitoredTask)
 @prefill_task
 def certificate_discovery(self: MonitoredTask):
@@ -42,11 +61,11 @@ def certificate_discovery(self: MonitoredTask):
             with open(path, "r+", encoding="utf-8") as _file:
                 body = _file.read()
                 if "BEGIN RSA PRIVATE KEY" in body:
-                    private_keys[cert_name] = body
+                    private_keys[cert_name] = ensure_private_key_valid(body)
                 else:
-                    certs[cert_name] = body
-        except OSError as exc:
-            LOGGER.warning("Failed to open file", exc=exc, file=path)
+                    certs[cert_name] = ensure_certificate_valid(body)
+        except (OSError, ValueError) as exc:
+            LOGGER.warning("Failed to open file or invalid format", exc=exc, file=path)
         discovered += 1
     for name, cert_data in certs.items():
         cert = CertificateKeyPair.objects.filter(managed=MANAGED_DISCOVERED % name).first()