Security hardening, multi-site portability, and a documentation and API-surface sweep

shopdb/__init__.py

@@ -48,7 +48,16 @@ from .plugins import plugin_manager
 # the literal values of C:\Enrollment\display-type.txt - so a plugin holding its
 # own copy of that map (geenforce did) can read core's instead of drifting from
 # it. Additive names on the import surface, minor bump.
-__contract_version__ = '0.18.0'
+# 0.19.0: get_dashboard_widgets returns DATA AND SHAPE, not a component name.
+# The old shape ('name' + 'component' + 'size') named a Vue component per
+# widget, which cannot survive a lean build - a plugin's component may never be
+# staged into the frontend bundle (ADR-013) - and five plugins were declaring
+# widgets that pointed at components nobody had written. Core now owns the
+# renderers and a card declares id / title / endpoint / render / severity /
+# permission / empty / position. BREAKING for any plugin still using the old
+# shape, which is why it is recorded here: the change itself shipped earlier
+# without a bump, and a contract that changes silently is not a contract.
+__contract_version__ = '0.19.0'
 
 # Product release version (see ADR-007). The product version and the
 # plugin-contract version above are distinct series with independent
@@ -134,6 +143,41 @@ def create_app(config_name: str = None) -> Flask:
         identity = jwt_data["sub"]
         return db.session.get(User, int(identity))
 
+    @app.after_request
+    def apply_security_headers(response):
+        """Baseline response headers. The app shipped with none of these.
+
+        Deliberately the three that cost nothing and break nothing:
+
+          nosniff        a response whose bytes and declared type disagree is
+                         not re-typed by the browser into something executable.
+                         This is the general form of the upload problem that
+                         shopdb/utils/uploads.py addresses per-file.
+          frame-ancestors
+                         same-origin only. The kiosks open routes directly
+                         rather than framing them, so this costs the fleet
+                         nothing and stops the UI being framed elsewhere and
+                         clicked through. Sent as X-Frame-Options too, because
+                         the display bays run browsers old enough to want it.
+          Referrer-Policy
+                         an asset id or a hostname in a path is not handed to
+                         whatever a user clicks through to.
+
+        NOT a full page CSP. This app serves an SPA with inline styles, so a
+        real script-src policy is a change worth making on its own with the
+        frontend in front of you - claiming one here by adding a permissive
+        header would be worse than having none.
+        """
+        response.headers.setdefault('X-Content-Type-Options', 'nosniff')
+        response.headers.setdefault('X-Frame-Options', 'SAMEORIGIN')
+        response.headers.setdefault('Referrer-Policy',
+                                    'strict-origin-when-cross-origin')
+        # setdefault: an upload response has already declared its own, stricter
+        # Content-Security-Policy, and this must not weaken it.
+        response.headers.setdefault('Content-Security-Policy',
+                                    "frame-ancestors 'self'")
+        return response
+
     return app