Fix/slack pre auth media download

plugins/platforms/slack/adapter.py

@@ -2572,6 +2572,28 @@ async def _handle_slack_message(self, event: dict) -> None:
             channel_type = "im"
         is_dm = channel_type in {"im", "mpim"}  # Both 1:1 and group DMs
 
+        # Reject unauthorized users before thread lookups, name resolution,
+        # or file downloads.  The final gateway runner auth check happens
+        # after MessageEvent construction, so adapter-side media fetches need
+        # the same auth chain up front.
+        _runner = getattr(getattr(self, "_message_handler", None), "__self__", None)
+        _auth_fn = getattr(_runner, "_is_user_authorized", None)
+        if user_id and callable(_auth_fn):
+            _source = self.build_source(
+                chat_id=channel_id,
+                chat_name="",
+                chat_type="dm" if is_dm else "group",
+                user_id=user_id,
+                user_name="",
+            )
+            if not _auth_fn(_source):
+                logger.warning(
+                    "[Slack] Early reject of unauthorized user %s in channel %s",
+                    user_id,
+                    channel_id,
+                )
+                return
+
         # Build thread_ts for session keying.
         # In channels: fall back to ts so each top-level @mention starts a
         #   new thread/session (the bot always replies in a thread).

tests/gateway/test_slack.py

@@ -1525,6 +1525,49 @@ async def test_file_shared_video_fallback_fetches_file_info(self, adapter):
         assert os.path.exists(msg_event.media_urls[0])
         assert msg_event.media_types == [SUPPORTED_VIDEO_TYPES[".mp4"]]
 
+    @pytest.mark.asyncio
+    async def test_unauthorized_message_does_not_fetch_file_info(
+        self,
+        adapter,
+        monkeypatch,
+    ):
+        """Global gateway auth must run before Slack file metadata fetches."""
+        monkeypatch.delenv("SLACK_ALLOW_ALL_USERS", raising=False)
+        monkeypatch.delenv("GATEWAY_ALLOW_ALL_USERS", raising=False)
+        monkeypatch.delenv("SLACK_ALLOWED_USERS", raising=False)
+        monkeypatch.setenv("GATEWAY_ALLOWED_USERS", "U_ALLOWED")
+
+        class Runner:
+            def _is_user_authorized(self, source):
+                return source.user_id == "U_ALLOWED"
+
+            async def handle(self, _event):
+                raise AssertionError("gateway handler should not run")
+
+        adapter._message_handler = Runner().handle
+        adapter._app.client.files_info = AsyncMock()
+
+        await adapter._handle_slack_message(
+            {
+                "type": "message",
+                "channel": "D123",
+                "channel_type": "im",
+                "user": "U_INTRUDER",
+                "text": "please read this",
+                "ts": "1234567890.000001",
+                "files": [
+                    {
+                        "id": "FSECRET",
+                        "mimetype": "text/plain",
+                        "name": "secret.txt",
+                    }
+                ],
+            }
+        )
+
+        adapter._app.client.files_info.assert_not_awaited()
+        adapter.handle_message.assert_not_called()
+
     @pytest.mark.asyncio
     async def test_download_failure_is_surfaced_in_message_text(self, adapter):
         """Attachment download failures (401/403/HTML-body/etc.) should be