feat: call page on its own origin, http://127.0.0.1:44548 (cinny #43)

The bundled Element Call page ran on the app's own origin
(http://localhost:44548), so the call frame could read the app's storage
(login token) and DOM. Serve it from http://127.0.0.1:44548 instead: the
same local server and bundle, a different origin.

- The local server binds 127.0.0.1 explicitly. The app is still loaded as
  http://localhost:44548 (its storage stays where it is; the engines try
  127.0.0.1 for `localhost`). Binding the name `localhost` could pick ::1
  only (Windows lists it first), and then 127.0.0.1 wouldn't answer.
- config.json: desktopCallOrigin = http://127.0.0.1:44548. cinny loads the
  call page from there only when this is set (cinny #43 PR).
- CSP frame-src allows http://127.0.0.1:44548.
- Permissions (on top of #22): the call page's origin gets microphone/
  camera/screen only; nothing else.
- The call page gets no IPC: the capability only matches
  http://localhost:44548.

Tested (Linux release build): the server listens on 127.0.0.1:44548 and
the app loads as http://localhost:44548; the call page loads from
127.0.0.1 inside the app under its CSP; from that frame parent.localStorage
and parent.document are SecurityError, while a same-origin frame (the old
setup) reads the app's storage. The call itself was tested in a simulated
desktop (Chromium, the WebView2 engine) against a local Synapse + LiveKit;
see the cinny PR. Rust tests 17 passed; Windows code type-checked.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

config.json

@@ -24,5 +24,6 @@
     "basename": "/"
   },
   "gifApiKey": "",
-  "webAppUrl": "https://chat.lotusguild.org"
+  "webAppUrl": "https://chat.lotusguild.org",
+  "desktopCallOrigin": "http://127.0.0.1:44548"
 }

src-tauri/src/lib.rs

@@ -955,7 +955,17 @@ pub fn run() {
             native::hotkeys::global_hotkeys_supported,
             native::hotkeys::set_global_hotkeys,
         ])
-        .plugin(tauri_plugin_localhost::Builder::new(port).build())
+        // Bound to 127.0.0.1 explicitly (cinny #43). The app is still loaded as
+        // http://localhost:{port} (its storage lives under that origin, and the
+        // engines try 127.0.0.1 for `localhost`); the bundled call page is
+        // loaded as http://127.0.0.1:{port}, a separate origin on the same
+        // server. Binding the name `localhost` could pick ::1 only (Windows
+        // lists it first), and then the call page wouldn't load.
+        .plugin(
+            tauri_plugin_localhost::Builder::new(port)
+                .host("127.0.0.1")
+                .build(),
+        )
         .plugin(
             // DECORATIONS is excluded: the custom-chrome toggle (set_custom_chrome)
             // owns the decorated flag. Letting window-state restore a saved

src-tauri/src/webview_permissions.rs

@@ -12,8 +12,13 @@
 //! - WebKitGTK doesn't say which frame asked; the check is on the page loaded
 //!   in the window. Frames are gated before the request gets this far by the
 //!   Permissions Policy: cinny only puts `microphone; camera` in the `allow=`
-//!   of the call frame (same origin on desktop), and cross-origin frames get
-//!   neither location nor notifications.
+//!   of the call frame, and cross-origin frames get neither location nor
+//!   notifications.
+//!
+//! The call frame (cinny #43): the bundled Element Call page is loaded from
+//! `http://127.0.0.1:{port}`, the same local server on a second origin, so it
+//! can't reach the app's storage. WebView2 reports that origin for the call's
+//! microphone/camera requests; it gets media and nothing else.
 
 use tauri::Url;
 
@@ -57,6 +62,14 @@ pub(crate) fn decide(kind: Kind, uri: &str, app: &AppOrigins, grants: &[Kind]) -
     if kind == Kind::Other {
         return Decision::Default;
     }
+    if app.is_call_frame(uri) {
+        // The call page: microphone/camera/screen only.
+        return if kind == Kind::Media && grants.contains(&kind) {
+            Decision::Allow
+        } else {
+            Decision::Deny
+        };
+    }
     if !app.contains(uri) {
         return Decision::Deny;
     }
@@ -76,9 +89,12 @@ fn origin_of(uri: &str) -> Option<Origin> {
     Some((url.scheme().to_owned(), host, url.port_or_known_default()))
 }
 
-/// The origins the app's own page is served from.
+/// The origins the app's own page is served from, and the call page's.
 #[derive(Clone, Debug)]
-pub(crate) struct AppOrigins(Vec<Origin>);
+pub(crate) struct AppOrigins {
+    app: Vec<Origin>,
+    call: Option<Origin>,
+}
 
 impl AppOrigins {
     /// Release builds load `http://localhost:{port}` (tauri-plugin-localhost).
@@ -93,11 +109,20 @@ impl AppOrigins {
                 uris.push(dev.to_string());
             }
         }
-        Self(uris.iter().filter_map(|u| origin_of(u)).collect())
+        Self {
+            app: uris.iter().filter_map(|u| origin_of(u)).collect(),
+            call: origin_of(&format!("http://127.0.0.1:{port}/")),
+        }
     }
 
+    /// The app's own page.
     pub(crate) fn contains(&self, uri: &str) -> bool {
-        origin_of(uri).is_some_and(|o| self.0.contains(&o))
+        origin_of(uri).is_some_and(|o| self.app.contains(&o))
+    }
+
+    /// The call page on its own origin (`http://127.0.0.1:{port}`).
+    pub(crate) fn is_call_frame(&self, uri: &str) -> bool {
+        origin_of(uri).is_some_and(|o| self.call.as_ref() == Some(&o))
     }
 }
 
@@ -204,6 +229,33 @@ mod tests {
         }
     }
 
+    #[test]
+    fn call_frame_gets_media_only() {
+        let app = app();
+        let call = "http://127.0.0.1:44548/public/element-call/index.html?widgetId=x";
+        assert!(app.is_call_frame(call));
+        assert!(!app.contains(call));
+        for grants in [LINUX_GRANTS, WINDOWS_GRANTS] {
+            assert_eq!(decide(Kind::Media, call, &app, grants), Decision::Allow);
+            for kind in [Kind::DeviceInfo, Kind::Notifications, Kind::Geolocation] {
+                assert_eq!(decide(kind, call, &app, grants), Decision::Deny, "{kind:?}");
+            }
+            assert_eq!(decide(Kind::Other, call, &app, grants), Decision::Default);
+        }
+        for not_call in [
+            "http://127.0.0.1:44549/",
+            "https://127.0.0.1:44548/",
+            "http://127.0.0.2:44548/",
+            "http://[::1]:44548/",
+        ] {
+            assert!(!app.is_call_frame(not_call), "{not_call}");
+            assert_eq!(
+                decide(Kind::Media, not_call, &app, WINDOWS_GRANTS),
+                Decision::Deny
+            );
+        }
+    }
+
     #[test]
     fn other_kinds_are_left_to_the_engine() {
         let app = app();

src-tauri/tauri.conf.json

@@ -71,7 +71,7 @@
   },
   "app": {
     "security": {
-      "csp": "default-src 'self'; script-src 'self' 'unsafe-eval' 'sha256-dT6noyex1I8o5CS9Sx/y8UOqwpZYIridpGz92gcObIM='; style-src 'self' 'unsafe-inline'; font-src 'self' data:; img-src 'self' data: blob: http: https:; media-src 'self' blob: data: mediastream: http: https:; worker-src 'self' blob:; frame-src 'self' blob: https://www.openstreetmap.org https://www.youtube-nocookie.com https://www.youtube.com https://player.vimeo.com https://www.tiktok.com https://www.dailymotion.com https://geo.dailymotion.com https://streamable.com https://player.twitch.tv https://clips.twitch.tv https://open.spotify.com https://w.soundcloud.com https://embed.music.apple.com https://platform.twitter.com https://www.instagram.com https://embed.tidal.com https://www.redditmedia.com https://embed.reddit.com https://embed.bsky.app https://www.loom.com https://player.kick.com https://www.mixcloud.com https://widget.deezer.com https://store.steampowered.com; connect-src 'self' blob: data: ipc: ws: wss: http: https: http://ipc.localhost; object-src 'none'; base-uri 'self'"
+      "csp": "default-src 'self'; script-src 'self' 'unsafe-eval' 'sha256-dT6noyex1I8o5CS9Sx/y8UOqwpZYIridpGz92gcObIM='; style-src 'self' 'unsafe-inline'; font-src 'self' data:; img-src 'self' data: blob: http: https:; media-src 'self' blob: data: mediastream: http: https:; worker-src 'self' blob:; frame-src 'self' blob: http://127.0.0.1:44548 https://www.openstreetmap.org https://www.youtube-nocookie.com https://www.youtube.com https://player.vimeo.com https://www.tiktok.com https://www.dailymotion.com https://geo.dailymotion.com https://streamable.com https://player.twitch.tv https://clips.twitch.tv https://open.spotify.com https://w.soundcloud.com https://embed.music.apple.com https://platform.twitter.com https://www.instagram.com https://embed.tidal.com https://www.redditmedia.com https://embed.reddit.com https://embed.bsky.app https://www.loom.com https://player.kick.com https://www.mixcloud.com https://widget.deezer.com https://store.steampowered.com; connect-src 'self' blob: data: ipc: ws: wss: http: https: http://ipc.localhost; object-src 'none'; base-uri 'self'"
     }
   }
 }