fix(security): widget consents and shared files cleared on logout; forged shares refused (#266, #267)

#266: remembered widget approvals (lotus.widgetConsent.*) survived logout,
so they applied silently to the next account on the device and listed the
previous account's rooms; clearPlaintextCaches now sweeps them. Space
structure, call membership and Lotus room-policy state join
PROTECTED_STATE_TYPES, so no widget can be granted them.

#267: any website could auto-submit a form to /share-target and land the
user in the share picker with attacker-chosen text and files. The worker
now refuses a share whose Origin is another site. (Sec-Fetch-Site, as the
issue suggested, never reaches a service worker: checked in Chromium.)
Origin null/absent, as the OS share sheet sends, stays accepted, and
/share now says the content came from another app or website. Both logout
paths await clearSharedPayload(); the server-forced one also clears the
soundboard clip cache, as #57 intended.

Fixes #266
Fixes #267

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/features/room/widgets/widgetUtils.test.ts

@@ -106,3 +106,19 @@ test('classifyWidgetCapabilities: reading protected state is fine, changing unpr
 test('loadWidgetConsent tolerates missing storage', () => {
   assert.equal(loadWidgetConsent('!r:x', 'w', 'https://w.example'), undefined);
 });
+
+test('[#266] space structure, call membership and Lotus room policy can never be granted', () => {
+  const { auto, ask } = classifyWidgetCapabilities(
+    [
+      'm.space.child',
+      'm.space.parent',
+      'org.matrix.msc3401.call',
+      'org.matrix.msc3401.call.member',
+      'm.call.member',
+      'io.lotus.voice_limit',
+      'io.lotus.room_quality',
+    ].map((t) => `org.matrix.msc2762.send.state_event:${t}`),
+  );
+  assert.equal(auto.size, 0);
+  assert.deepEqual(ask, []);
+});

src/app/features/room/widgets/widgetUtils.ts

@@ -67,6 +67,16 @@ export const PROTECTED_STATE_TYPES: ReadonlySet<string> = new Set([
   'm.room.third_party_invite',
   'im.vector.modular.widgets',
   'm.widget',
+  // [Gitea #266] Space structure, call membership and Lotus room policy: a
+  // widget could restructure a space, fake call membership or lift the
+  // voice-channel limit, so these can't be granted even with consent.
+  'm.space.child',
+  'm.space.parent',
+  'org.matrix.msc3401.call',
+  'org.matrix.msc3401.call.member',
+  'm.call.member',
+  'io.lotus.voice_limit',
+  'io.lotus.room_quality',
 ]);
 
 export type WidgetPermissionRequest = {
@@ -137,8 +147,11 @@ export const classifyWidgetCapabilities = (
  */
 export type StoredWidgetConsent = { url: string; allowed: Capability[]; denied: Capability[] };
 
+// [Gitea #266] Swept on logout by clearPlaintextCaches, so one account's
+// approvals never apply to the next account on the same device.
+export const WIDGET_CONSENT_PREFIX = 'lotus.widgetConsent.';
 export const widgetConsentKey = (roomId: string, widgetId: string): string =>
-  `lotus.widgetConsent.${roomId}.${widgetId}`;
+  `${WIDGET_CONSENT_PREFIX}${roomId}.${widgetId}`;
 
 export const loadWidgetConsent = (
   roomId: string,