providers/oauth2: fix CVE-2024-21637 (#8104)

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

authentik/providers/oauth2/tests/test_authorize.py

@@ -87,6 +87,25 @@ class TestAuthorize(OAuthTestCase):
             )
             OAuthAuthorizationParams.from_request(request)
 
+    def test_blocked_redirect_uri(self):
+        """test missing/invalid redirect URI"""
+        OAuth2Provider.objects.create(
+            name=generate_id(),
+            client_id="test",
+            authorization_flow=create_test_flow(),
+            redirect_uris="data:local.invalid",
+        )
+        with self.assertRaises(RedirectUriError):
+            request = self.factory.get(
+                "/",
+                data={
+                    "response_type": "code",
+                    "client_id": "test",
+                    "redirect_uri": "data:localhost",
+                },
+            )
+            OAuthAuthorizationParams.from_request(request)
+
     def test_invalid_redirect_uri_empty(self):
         """test missing/invalid redirect URI"""
         provider = OAuth2Provider.objects.create(

authentik/providers/oauth2/views/authorize.py

@@ -76,6 +76,7 @@ PLAN_CONTEXT_PARAMS = "goauthentik.io/providers/oauth2/params"
 SESSION_KEY_LAST_LOGIN_UID = "authentik/providers/oauth2/last_login_uid"
 
 ALLOWED_PROMPT_PARAMS = {PROMPT_NONE, PROMPT_CONSENT, PROMPT_LOGIN}
+FORBIDDEN_URI_SCHEMES = {"javascript", "data", "vbscript"}
 
 
 @dataclass(slots=True)
@@ -179,6 +180,10 @@ class OAuthAuthorizationParams:
         self.check_scope(github_compat)
         self.check_nonce()
         self.check_code_challenge()
+        if self.request:
+            raise AuthorizeError(
+                self.redirect_uri, "request_not_supported", self.grant_type, self.state
+            )
 
     def check_redirect_uri(self):
         """Redirect URI validation."""
@@ -216,10 +221,9 @@ class OAuthAuthorizationParams:
                     redirect_uri_expected=allowed_redirect_urls,
                 )
                 raise RedirectUriError(self.redirect_uri, allowed_redirect_urls)
-        if self.request:
-            raise AuthorizeError(
-                self.redirect_uri, "request_not_supported", self.grant_type, self.state
-            )
+        # Check against forbidden schemes
+        if urlparse(self.redirect_uri).scheme in FORBIDDEN_URI_SCHEMES:
+            raise RedirectUriError(self.redirect_uri, allowed_redirect_urls)
 
     def check_scope(self, github_compat=False):
         """Ensure openid scope is set in Hybrid flows, or when requesting an id_token"""

authentik/providers/oauth2/views/token.py

@@ -6,6 +6,7 @@ from hashlib import sha256
 from re import error as RegexError
 from re import fullmatch
 from typing import Any, Optional
+from urllib.parse import urlparse
 
 from django.http import HttpRequest, HttpResponse
 from django.utils import timezone
@@ -55,6 +56,7 @@ from authentik.providers.oauth2.models import (
     RefreshToken,
 )
 from authentik.providers.oauth2.utils import TokenResponse, cors_allow, extract_client_auth
+from authentik.providers.oauth2.views.authorize import FORBIDDEN_URI_SCHEMES
 from authentik.sources.oauth.models import OAuthSource
 from authentik.stages.password.stage import PLAN_CONTEXT_METHOD, PLAN_CONTEXT_METHOD_ARGS
 
@@ -206,6 +208,10 @@ class TokenParams:
                 ).from_http(request)
                 raise TokenError("invalid_client")
 
+        # Check against forbidden schemes
+        if urlparse(self.redirect_uri).scheme in FORBIDDEN_URI_SCHEMES:
+            raise TokenError("invalid_request")
+
         self.authorization_code = AuthorizationCode.objects.filter(code=raw_code).first()
         if not self.authorization_code:
             LOGGER.warning("Code does not exist", code=raw_code)