fix: Prevent login via credentials when Auth Method is Mealie (#4370)

docs/docs/documentation/getting-started/authentication/oidc-v2.md

@@ -18,6 +18,8 @@ Mealie supports 3rd party authentication via [OpenID Connect (OIDC)](https://ope
 
 Signing in with OAuth will automatically find your account in Mealie and link to it. If a user does not exist in Mealie, then one will be created (if enabled), but will be unable to log in with any other authentication method. An admin can configure another authentication method for such a user.
 
+If a user previously accessed Mealie via credentials and you want to no longer allow users to log in with `LDAP` or `Mealie` credentials, then you can set the user's *Authentication Method* to `OIDC`. Conversely, if a user's auth method is not `OIDC`, then they can still log in with whatever their auth method is as well as OIDC.
+
 ## Provider Setup
 
 Before you can start using OIDC Authentication, you must first configure a new client application in your identity provider. Your identity provider must support the OAuth **Authorization Code flow with PKCE**. The steps will vary by provider, but generally, the steps are as follows.

mealie/core/security/providers/credentials_provider.py

@@ -7,6 +7,7 @@
 from mealie.core.exceptions import UserLockedOut
 from mealie.core.security.hasher import get_hasher
 from mealie.core.security.providers.auth_provider import AuthProvider
+from mealie.db.models.users.users import AuthMethod
 from mealie.repos.all_repositories import get_repositories
 from mealie.schema.user.auth import CredentialsRequest
 from mealie.services.user_services.user_service import UserService
@@ -27,11 +28,13 @@ def authenticate(self) -> tuple[str, timedelta] | None:
         user = self.try_get_user(self.data.username)
 
         if not user:
-            # To prevent user enumeration we perform the verify_password computation to ensure
-            # server side time is relatively constant and not vulnerable to timing attacks.
-            CredentialsProvider.verify_password(
-                "abc123cba321",
-                "$2b$12$JdHtJOlkPFwyxdjdygEzPOtYmdQF5/R5tHxw5Tq8pxjubyLqdIX5i",
+            self.verify_fake_password()
+            return None
+
+        if user.auth_method != AuthMethod.MEALIE:
+            self.verify_fake_password()
+            self._logger.warning(
+                "Found user but their auth method is not 'Mealie'. Unable to continue with credentials login"
             )
             return None
 
@@ -52,6 +55,14 @@ def authenticate(self) -> tuple[str, timedelta] | None:
         user = db.users.update(user.id, user)
         return self.get_access_token(user, self.data.remember_me)  # type: ignore
 
+    def verify_fake_password(self):
+        # To prevent user enumeration we perform the verify_password computation to ensure
+        # server side time is relatively constant and not vulnerable to timing attacks.
+        CredentialsProvider.verify_password(
+            "abc123cba321",
+            "$2b$12$JdHtJOlkPFwyxdjdygEzPOtYmdQF5/R5tHxw5Tq8pxjubyLqdIX5i",
+        )
+
     @staticmethod
     def verify_password(plain_password: str, hashed_password: str) -> bool:
         """Compares a plain string to a hashed password"""

mealie/core/security/providers/ldap_provider.py

@@ -23,9 +23,13 @@ def __init__(self, session: Session, data: CredentialsRequest) -> None:
         self.conn = None
 
     def authenticate(self) -> tuple[str, timedelta] | None:
-        """Attempt to authenticate a user given a username and password"""
+        """Attempt to authenticate a user given a username and password against an LDAP provider"""
+        # When LDAP is enabled, we need to still also support authentication with Mealie backend
+        # First we look to see if we have a user. If we don't we'll attempt to create one with LDAP
+        # If we do find a user, we will check if their auth method is LDAP and attempt to authenticate
+        # Otherwise, we will proceed with Mealie authentication
         user = self.try_get_user(self.data.username)
-        if not user or user.password == "LDAP" or user.auth_method == AuthMethod.LDAP:
+        if not user or user.auth_method == AuthMethod.LDAP:
             user = self.get_user()
             if user:
                 return self.get_access_token(user, self.data.remember_me)

tests/unit_tests/core/security/providers/test_credentials_provider.py

@@ -0,0 +1,23 @@
+from mealie.core.security.providers.credentials_provider import CredentialsProvider
+from mealie.db.models.users.users import AuthMethod
+from mealie.schema.user.auth import CredentialsRequest
+from tests.utils.fixture_schemas import TestUser
+
+
+def test_login(unique_user: TestUser):
+    data = {"username": unique_user.username, "password": unique_user.password}
+    auth_provider = CredentialsProvider(unique_user.repos.session, CredentialsRequest(**data))
+
+    assert auth_provider.authenticate() is not None
+
+
+def test_login_incorrect_auth_method(unique_user: TestUser):
+    db = unique_user.repos
+    user = db.users.get_by_username(unique_user.username)
+    user.auth_method = AuthMethod.OIDC
+    db.users.update(unique_user.user_id, user)
+
+    data = {"username": unique_user.username, "password": unique_user.password}
+    auth_provider = CredentialsProvider(db.session, CredentialsRequest(**data))
+
+    assert auth_provider.authenticate() is None