chore: surface event if proxy token mismatches

tests/unit/utils/test_wsgi.py

@@ -12,6 +12,7 @@
 
 import pretend
 import pytest
+import sentry_sdk
 
 from sqlalchemy import type_coerce
 from sqlalchemy.dialects.postgresql import INET
@@ -43,6 +44,32 @@ def test_skips_headers(self):
         assert resp is response
         assert app.calls == [pretend.call({}, start_response)]
 
+    def test_token_mismatch_sends_sentry(self, monkeypatch):
+        """In the event someone submits the WAREHOUSE_TOKEN header with an
+        incorrect value, we send a Sentry.
+        """
+        mock_set_context = pretend.call_recorder(lambda *a, **kw: None)
+        monkeypatch.setattr(sentry_sdk, "set_context", mock_set_context)
+        mock_capture_message = pretend.call_recorder(lambda *a, **kw: None)
+        monkeypatch.setattr(sentry_sdk, "capture_message", mock_capture_message)
+
+        response = pretend.stub()
+        app = pretend.call_recorder(lambda e, s: response)
+
+        environ = {"HTTP_WAREHOUSE_TOKEN": "NOPE"}
+        start_response = pretend.stub()
+
+        resp = wsgi.ProxyFixer(app, token="1234", ip_salt="pepa")(
+            environ, start_response
+        )
+
+        assert resp is response
+        assert app.calls == [pretend.call({}, start_response)]
+        assert mock_set_context.calls == [pretend.call("ProxyFixer", {"token": "NOPE"})]
+        assert mock_capture_message.calls == [
+            pretend.call("Invalid Proxy Token", level="warning")
+        ]
+
     def test_accepts_warehouse_headers(self):
         response = pretend.stub()
         app = pretend.call_recorder(lambda e, s: response)

warehouse/utils/wsgi.py

@@ -16,6 +16,8 @@
 
 from typing import TYPE_CHECKING
 
+import sentry_sdk
+
 from sqlalchemy import type_coerce
 from sqlalchemy.dialects.postgresql import INET
 from sqlalchemy.exc import NoResultFound
@@ -66,11 +68,24 @@ def __call__(self, environ, start_response):
             }
 
             host = environ.get("HTTP_WAREHOUSE_HOST", "")
+
         # If we're not getting headers from a trusted third party via the
         # specialized Warehouse-* headers, then we'll fall back to looking at
         # X-Forwarded-* headers, assuming that whatever we have in front of us
         # will strip invalid ones.
         else:
+            # If there IS a token, but it doesn't match, then tell us about it.
+            if request_token is not None and not hmac.compare_digest(
+                self.token, request_token
+            ):
+                sentry_sdk.set_context(
+                    self.__class__.__name__, {"token": request_token}
+                )
+                sentry_sdk.capture_message(
+                    "Invalid Proxy Token",
+                    level="warning",
+                )
+
             proto = environ.get("HTTP_X_FORWARDED_PROTO", "")
 
             # Special case: if we don't see a X-Forwarded-For, this may be a local