feat: add a master OAuth / OIDC enable toggle in Authentication settings (#26988)

The OAuth / OIDC section in Admin Settings > Authentication had no
enable/disable switch, unlike the LDAP section above it. Add one that
persists via the existing Save flow and actually gates OAuth sign-in,
mirroring how the LDAP toggle works.

- config: new ENABLE_OAUTH persistent config ('oauth.enable'), defaulting
  to True so existing deployments with a provider configured keep working.
- oauth: expose ENABLE_OAUTH via the OAuth runtime config and reject the
  login and callback handlers with 404 when it is disabled.
- /api/config: report no OAuth providers when disabled so the login page
  hides the OAuth buttons (and cannot auto-redirect), without clearing the
  admin's provider configuration.
- auths: expose ENABLE_OAUTH through the admin OAuth config get/update
  endpoints (OAuthConfigForm + OAUTH_CONFIG_KEYS).
- Authentication.svelte: bind the OAuth / OIDC header Switch to the
  persisted oauthConfig.ENABLE_OAUTH and collapse the section when off,
  matching the LDAP header (size, weight, alignment).

backend/open_webui/config.py

@@ -2429,6 +2429,11 @@ if JWT_EXPIRES_IN == '-1':
 # OAuth config
 ####################################
 
+# Master switch for OAuth/OIDC sign-in. Defaults to enabled so existing
+# deployments that already have a provider configured keep working; admins can
+# turn it off to disable OAuth login without clearing their provider settings.
+ENABLE_OAUTH = os.getenv('ENABLE_OAUTH', 'True').lower() == 'true'
+
 ENABLE_OAUTH_SIGNUP = os.getenv('ENABLE_OAUTH_SIGNUP', 'False').lower() == 'true'
 
 OAUTH_AUTO_REDIRECT = os.getenv('OAUTH_AUTO_REDIRECT', 'False').lower() == 'true'
@@ -3091,6 +3096,7 @@ DEFAULT_CONFIG = {
     'auth.api_key.endpoint_restrictions': ENABLE_API_KEYS_ENDPOINT_RESTRICTIONS,
     'auth.api_key.allowed_endpoints': API_KEYS_ALLOWED_ENDPOINTS,
     'auth.jwt_expiry': JWT_EXPIRES_IN,
+    'oauth.enable': ENABLE_OAUTH,
     'oauth.enable_signup': ENABLE_OAUTH_SIGNUP,
     'oauth.auto_redirect': OAUTH_AUTO_REDIRECT,
     'oauth.refresh_token.include_scope': OAUTH_REFRESH_TOKEN_INCLUDE_SCOPE,

backend/open_webui/main.py

@@ -1998,6 +1998,7 @@ async def get_app_config(request: Request):
     license_metadata = getattr(app.state, 'LICENSE_METADATA', None)
     user_count = await Users.get_num_users() if license_metadata else None
     config = await Config.get_many(
+        'oauth.enable',
         'oauth.auto_redirect',
         'ldap.enable',
         'ui.enable_signup',
@@ -2052,7 +2053,13 @@ async def get_app_config(request: Request):
         'version': VERSION,
         'default_locale': str(DEFAULT_LOCALE),
         'oauth': {
-            'providers': {name: config.get('name', name) for name, config in OAUTH_PROVIDERS.items()},
+            # Hide providers (and thus the login buttons / auto-redirect) when OAuth
+            # is disabled, without clearing the admin's provider configuration.
+            'providers': (
+                {name: provider.get('name', name) for name, provider in OAUTH_PROVIDERS.items()}
+                if config.get('oauth.enable', True)
+                else {}
+            ),
             'auto_redirect': config.get('oauth.auto_redirect'),
         },
         'features': {

backend/open_webui/routers/auths.py

@@ -1304,6 +1304,7 @@ class OAuthConfigForm(BaseModel):
     """All OAuth/OIDC settings exposed to the admin panel."""
 
     # General OAuth
+    ENABLE_OAUTH: bool | None = None
     ENABLE_OAUTH_SIGNUP: bool | None = None
     OAUTH_MERGE_ACCOUNTS_BY_EMAIL: bool | None = None
     OAUTH_AUTO_REDIRECT: bool | None = None
@@ -1359,6 +1360,7 @@ OAUTH_COMMA_LIST_FIELDS = {
 
 
 OAUTH_CONFIG_KEYS = {
+    'ENABLE_OAUTH': 'oauth.enable',
     'ENABLE_OAUTH_SIGNUP': 'oauth.enable_signup',
     'OAUTH_MERGE_ACCOUNTS_BY_EMAIL': 'oauth.merge_accounts_by_email',
     'OAUTH_AUTO_REDIRECT': 'oauth.auto_redirect',

backend/open_webui/utils/oauth.py

@@ -35,6 +35,7 @@ from mcp.shared.auth import (
 from open_webui.config import (
     DEFAULT_USER_ROLE,
     ENABLE_OAUTH_GROUP_CREATION,
+    ENABLE_OAUTH,
     ENABLE_OAUTH_GROUP_MANAGEMENT,
     ENABLE_OAUTH_ROLE_MANAGEMENT,
     ENABLE_OAUTH_SIGNUP,
@@ -120,6 +121,7 @@ OAUTH_RESOURCE_PARAMETER_MODES = {'auto', 'include', 'omit'}
 
 OAUTH_RUNTIME_CONFIG = {
     'DEFAULT_USER_ROLE': ('ui.default_user_role', DEFAULT_USER_ROLE),
+    'ENABLE_OAUTH': ('oauth.enable', ENABLE_OAUTH),
     'ENABLE_OAUTH_SIGNUP': ('oauth.enable_signup', ENABLE_OAUTH_SIGNUP),
     'OAUTH_REFRESH_TOKEN_INCLUDE_SCOPE': (
         'oauth.refresh_token.include_scope',
@@ -1670,6 +1672,8 @@ class OAuthManager:
 
     async def handle_login(self, request, provider):
         auth_config = await get_oauth_runtime_config()
+        if not auth_config.ENABLE_OAUTH:
+            raise HTTPException(404)
         if provider not in OAUTH_PROVIDERS:
             raise HTTPException(404)
         # If the provider has a custom redirect URL, use that, otherwise automatically generate one
@@ -1690,6 +1694,8 @@ class OAuthManager:
 
     async def handle_callback(self, request, provider, response, db=None):
         auth_config = await get_oauth_runtime_config()
+        if not auth_config.ENABLE_OAUTH:
+            raise HTTPException(404)
         if provider not in OAUTH_PROVIDERS:
             raise HTTPException(404)