Merge #1997

1997: Prevent traceback when using non-email in login r=mergify[bot] a=ghostwheel42

There's a traceback when the username used to log via SMTPAUTH
in is not an email address:

=== before ===
```
[...] ERROR in app: Exception on /internal/auth/email [GET]
Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 1179, in _execute_context
    context = constructor(dialect, self, conn, *args)
  File "/usr/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 719, in _init_compiled
    param.append(processors[key](compiled_params[key]))
  File "/usr/lib/python3.9/site-packages/sqlalchemy/sql/type_api.py", line 1201, in process
    return process_param(value, dialect)
  File "/app/mailu/models.py", line 60, in process_bind_param
    localpart, domain_name = value.lower().rsplit('`@',` 1)
ValueError: not enough values to unpack (expected 2, got 1)
[...]
[parameters: [{'%(140657157923216 param)s': 'foobar'}]]
```

=== after ===
```
[...] WARNING in nginx: Invalid user 'foobar': (builtins.ValueError) invalid email address (no "`@")`
```

## What type of PR?

enhancement

## What does this PR do?

replace traceback (ERROR) with error message (WARNING)

### Related issue(s)

## Prerequisites
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [ ] In case of feature or enhancement: documentation updated accordingly
- [ ] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/workflow.html#changelog) entry file.


Co-authored-by: Alexander Graf <ghostwheel42@users.noreply.github.com>

core/admin/mailu/internal/nginx.py

@@ -5,6 +5,7 @@ import re
 import urllib
 import ipaddress
 import socket
+import sqlalchemy.exc
 import tenacity
 
 SUPPORTED_AUTH_METHODS = ["none", "plain"]
@@ -90,9 +91,13 @@ def handle_authentication(headers):
         except:
             app.logger.warn(f'Received undecodable user/password from nginx: {raw_user_email!r}/{raw_password!r}')
         else:
+            try:
                 user = models.User.query.get(user_email)
-            ip = urllib.parse.unquote(headers["Client-Ip"])
-            if check_credentials(user, password, ip, protocol):
+            except sqlalchemy.exc.StatementError as exc:
+                exc = str(exc).split('\n', 1)[0]
+                app.logger.warn(f'Invalid user {user_email!r}: {exc}')
+            else:
+                if check_credentials(user, password, urllib.parse.unquote(headers["Client-Ip"]), protocol):
                     server, port = get_server(headers["Auth-Protocol"], True)
                     return {
                         "Auth-Status": "OK",

core/admin/mailu/models.py

@@ -57,6 +57,8 @@ class IdnaEmail(db.TypeDecorator):
 
     def process_bind_param(self, value, dialect):
         """ encode unicode domain part of email address to punycode """
+        if not '@' in value:
+            raise ValueError('invalid email address (no "@")')
         localpart, domain_name = value.lower().rsplit('@', 1)
         if '@' in localpart:
             raise ValueError('email local part must not contain "@"')