fixup! Bug 27476: Implement about:torconnect captive portal within Tor Browser

Bug 42184: Make torconnect redirect compatible with blank home page.

browser/components/torconnect/TorConnectChild.sys.mjs

@@ -2,4 +2,78 @@
 
 import { RemotePageChild } from "resource://gre/actors/RemotePageChild.sys.mjs";
 
-export class TorConnectChild extends RemotePageChild {}
+export class TorConnectChild extends RemotePageChild {
+  /**
+   * Whether we have redirected the page (after bootstrapping) or not.
+   *
+   * @type {boolean}
+   */
+  #redirected = false;
+
+  /**
+   * If bootstrapping is complete, or TorConnect is disabled, we redirect the
+   * page.
+   */
+  async #maybeRedirect() {
+    if (await this.sendQuery("torconnect:should-show")) {
+      // Enabled and not yet bootstrapped.
+      return;
+    }
+    if (this.#redirected) {
+      return;
+    }
+    this.#redirected = true;
+
+    const redirect = new URLSearchParams(
+      new URL(this.contentWindow.document.location.href).search
+    ).get("redirect");
+
+    // Fallback in error cases:
+    let replaceURI = "about:tor";
+    try {
+      const url = new URL(
+        redirect
+          ? decodeURIComponent(redirect)
+          : // NOTE: We expect no redirect when address is entered manually, or
+            // about:torconnect is opened from preferences or urlbar.
+            // Go to the home page.
+            await this.sendQuery("torconnect:home-page")
+      );
+      // Do not allow javascript URI. See tor-browser#41766
+      if (
+        ["about:", "file:", "https:", "http:"].includes(url.protocol) ||
+        // Allow blank page. See tor-browser#42184.
+        // Blank page's are given as a chrome URL rather than "about:blank".
+        url.href === "chrome://browser/content/blanktab.html"
+      ) {
+        replaceURI = url.href;
+      } else {
+        console.error(`Scheme is not allowed "${redirect}"`);
+      }
+    } catch {
+      console.error(`Invalid redirect URL "${redirect}"`);
+    }
+
+    // Replace the destination to prevent "about:torconnect" entering the
+    // history.
+    // NOTE: This is done here, in the window actor, rather than in content
+    // because we have the privilege to redirect to a "chrome:" uri here (for
+    // when the HomePage is set to be blank).
+    this.contentWindow.location.replace(replaceURI);
+  }
+
+  actorCreated() {
+    super.actorCreated();
+    // about:torconnect could need to be immediately redirected. E.g. if it is
+    // reached after bootstrapping.
+    this.#maybeRedirect();
+  }
+
+  receiveMessage(message) {
+    super.receiveMessage(message);
+
+    if (message.name === "torconnect:state-change") {
+      this.#maybeRedirect();
+    }
+  }
+}

browser/components/torconnect/TorConnectParent.sys.mjs

 // Copyright (c) 2021, The Tor Project, Inc.
 
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
 const { TorStrings } = ChromeUtils.import("resource:///modules/TorStrings.jsm");
 import {
   InternetStatus,
@@ -15,6 +17,12 @@ import {
 
 const BroadcastTopic = "about-torconnect:broadcast";
 
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  HomePage: "resource:///modules/HomePage.jsm",
+});
+
 /*
 This object is basically a marshalling interface between the TorConnect module
 and a particular about:torconnect page
@@ -167,6 +175,11 @@ export class TorConnectParent extends JSWindowActorParent {
 
   async receiveMessage(message) {
     switch (message.name) {
+      case "torconnect:should-show":
+        return Promise.resolve(TorConnect.shouldShowTorConnect);
+      case "torconnect:home-page":
+        // If there are multiple home pages, just load the first one.
+        return Promise.resolve(TorConnect.fixupURIs(lazy.HomePage.get())[0]);
       case "torconnect:set-quickstart":
         TorSettings.quickstart.enabled = message.data;
         TorSettings.saveToPrefs().applySettings();

browser/components/torconnect/content/aboutTorConnect.js

@@ -136,10 +136,6 @@ class AboutTorConnect {
     tryBridgeButton: document.querySelector(this.selectors.buttons.tryBridge),
   });
 
-  // a redirect url can be passed as a query parameter for the page to
-  // forward us to once bootstrap completes (otherwise the window will just close)
-  redirect = null;
-
   uiState = {
     currentState: UIStates.ConnectToTor,
     allowAutomaticLocation: true,
@@ -425,11 +421,6 @@ class AboutTorConnect {
     this.setLongText(TorStrings.settings.torPreferencesDescription);
     this.setProgress("", showProgressbar, 100);
     this.hideButtons();
-
-    // redirects page to the requested redirect url, removes about:torconnect
-    // from the page stack, so users cannot accidentally go 'back' to the
-    // now unresponsive page
-    window.location.replace(this.redirect);
   }
 
   update_Disabled(state) {
@@ -822,23 +813,6 @@ class AboutTorConnect {
   }
 
   async init() {
-    // if the user gets here manually or via the button in the urlbar
-    // then we will redirect to about:tor
-    this.redirect = "about:tor";
-
-    // see if a user has a final destination after bootstrapping
-    let params = new URLSearchParams(new URL(document.location.href).search);
-    if (params.has("redirect")) {
-      try {
-        const redirect = new URL(decodeURIComponent(params.get("redirect")));
-        if (/^(?:https?|about):$/.test(redirect.protocol)) {
-          this.redirect = redirect.href;
-        }
-      } catch (e) {
-        console.error(e, `Invalid redirect URL "${params.get("redirect")}"!`);
-      }
-    }
-
     let args = await RPMSendQuery("torconnect:get-init-args");
 
     // various constants