Log failed login attempts

src/paperless/apps.py

@@ -0,0 +1,15 @@
+from django.apps import AppConfig
+from django.utils.translation import gettext_lazy as _
+from paperless.signals import handle_failed_login
+
+
+class PaperlessConfig(AppConfig):
+    name = "paperless"
+
+    verbose_name = _("Paperless")
+
+    def ready(self):
+        from django.contrib.auth.signals import user_login_failed
+
+        user_login_failed.connect(handle_failed_login)
+        AppConfig.ready(self)

src/paperless/settings.py

@@ -416,6 +416,13 @@ if _paperless_url:
         # always allow localhost. Necessary e.g. for healthcheck in docker.
         ALLOWED_HOSTS = [_paperless_uri.hostname] + ["localhost"]
 
+# For use with trusted proxies
+_trusted_proxies = os.getenv("PAPERLESS_TRUSTED_PROXIES")
+if _trusted_proxies:
+    TRUSTED_PROXIES = _trusted_proxies.split(",")
+else:
+    TRUSTED_PROXIES = []
+
 # The secret key has a default that should be fine so long as you're hosting
 # Paperless on a closed network.  However, if you're putting this anywhere
 # public, you should change the key to something unique and verbose.

src/paperless/signals.py

@@ -0,0 +1,32 @@
+import logging
+
+from django.conf import settings
+from ipware import get_client_ip
+
+logger = logging.getLogger("paperless.auth")
+
+
+# https://docs.djangoproject.com/en/4.1/ref/contrib/auth/#django.contrib.auth.signals.user_login_failed
+def handle_failed_login(sender, credentials, request, **kwargs):
+    client_ip, is_routable = get_client_ip(
+        request,
+        proxy_trusted_ips=settings.TRUSTED_PROXIES,
+    )
+    if client_ip is None:
+        logger.info(
+            f"Login failed for user `{credentials['username']}`."
+            + " Unable to determine IP address.",
+        )
+    else:
+        if is_routable:
+            # We got the client's IP address
+            logger.info(
+                f"Login failed for user `{credentials['username']}`"
+                + f" from IP `{client_ip}.`",
+            )
+        else:
+            # The client's IP address is private
+            logger.info(
+                f"Login failed for user `{credentials['username']}`"
+                + f" from private IP `{client_ip}.`",
+            )