Bug 1882422: Use a local testing page to return complex data and make use of it in C++-land r=peterv

- Create a local page we will access via an about: URL
- In that page, demonstrate how to do some stuff, then fire a custom event
  indicating its stuff is done _and_ return complex data in that event.
  console.log() didn't seem to be visible in the HiddenWindow, so I also
  piped out debug strings for development purposes, so they can be
  console.logged in the Service, where we can see them.
- Instead of listening for DOMContentLoaded/pageshow, instead listen for
  the new CustomEvent.
- In UserCharacteristicsPageService, receive the data from the page and
  populate the appropriate Glean metrics
- Refactor the calling of nsUserCharacteristics::PopulateData() and
  SubmitPing().  Now we call PopulateDataAndEventuallySubmit() which will
  eventually call SubmitPing after our promise is resolved.
- To make it a little cleaner (so ContentPageStuff() isn't calling
  SubmitPing()) we return the promise out of ContentPageStuff() that
  PopulateDataAndEventuallySubmit() will await and then call SubmitPing()
  when that promise resolves

Differential Revision: https://phabricator.services.mozilla.com/D203055

docshell/base/nsAboutRedirector.cpp

@@ -108,6 +108,12 @@ static const RedirEntry kRedirMap[] = {
     {"credits", "https://www.mozilla.org/credits/",
      nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
          nsIAboutModule::URI_MUST_LOAD_IN_CHILD},
+    {"fingerprinting",
+     "chrome://global/content/usercharacteristics/usercharacteristics.html",
+     nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
+         nsIAboutModule::HIDE_FROM_ABOUTABOUT | nsIAboutModule::ALLOW_SCRIPT |
+         nsIAboutModule::URI_MUST_LOAD_IN_CHILD |
+         nsIAboutModule::URI_CAN_LOAD_IN_PRIVILEGEDABOUT_PROCESS},
     {"httpsonlyerror", "chrome://global/content/httpsonlyerror/errorpage.html",
      nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
          nsIAboutModule::URI_CAN_LOAD_IN_CHILD | nsIAboutModule::ALLOW_SCRIPT |

docshell/build/components.conf

@@ -16,6 +16,7 @@ about_pages = [
     'crashgpu',
     'crashextensions',
     'credits',
+    'fingerprinting',
     'httpsonlyerror',
     'license',
     'logging',

dom/security/nsContentSecurityUtils.cpp

@@ -1367,6 +1367,7 @@ void nsContentSecurityUtils::AssertAboutPageHasCSP(Document* aDocument) {
                  StringBeginsWith(aboutSpec, "about:preferences"_ns) ||
                  StringBeginsWith(aboutSpec, "about:settings"_ns) ||
                  StringBeginsWith(aboutSpec, "about:downloads"_ns) ||
+                 StringBeginsWith(aboutSpec, "about:fingerprinting"_ns) ||
                  StringBeginsWith(aboutSpec, "about:asrouter"_ns) ||
                  StringBeginsWith(aboutSpec, "about:newtab"_ns) ||
                  StringBeginsWith(aboutSpec, "about:logins"_ns) ||

toolkit/actors/UserCharacteristicsChild.sys.mjs

@@ -16,12 +16,11 @@ export class UserCharacteristicsChild extends JSWindowActorChild {
   handleEvent(event) {
     lazy.console.debug("Got ", event.type);
     switch (event.type) {
-      case "DOMContentLoaded":
-      case "pageshow":
+      case "UserCharacteristicsDataDone":
         lazy.console.debug("creating IdleDispatch");
         ChromeUtils.idleDispatch(() => {
           lazy.console.debug("sending PageReady");
-          this.sendAsyncMessage("UserCharacteristics::PageReady");
+          this.sendAsyncMessage("UserCharacteristics::PageReady", event.detail);
         });
         break;
     }

toolkit/actors/UserCharacteristicsParent.sys.mjs

@@ -3,7 +3,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
-//import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
 
 const lazy = {};
 ChromeUtils.defineLazyGetter(lazy, "console", () => {
@@ -13,20 +13,22 @@ ChromeUtils.defineLazyGetter(lazy, "console", () => {
   });
 });
 
-/*
 XPCOMUtils.defineLazyServiceGetter(
   lazy,
   "UserCharacteristicsPageService",
   "@mozilla.org/user-characteristics-page;1",
   "nsIUserCharacteristicsPageService"
 );
-*/
 
 export class UserCharacteristicsParent extends JSWindowActorParent {
   receiveMessage(aMessage) {
     lazy.console.debug("Got ", aMessage.name);
     if (aMessage.name == "UserCharacteristics::PageReady") {
       lazy.console.debug("Got pageReady");
+      lazy.UserCharacteristicsPageService.pageLoaded(
+        this.browsingContext,
+        aMessage.data
+      );
     }
   }
 }

toolkit/components/resistfingerprinting/RFPHelper.sys.mjs

@@ -114,10 +114,11 @@ class _RFPHelper {
       child: {
         esModuleURI: "resource://gre/actors/UserCharacteristicsChild.sys.mjs",
         events: {
-          DOMContentLoaded: {},
-          pageshow: {},
+          UserCharacteristicsDataDone: { wantUntrusted: true },
         },
       },
+      matches: ["about:fingerprinting"],
+      remoteTypes: ["privilegedabout"],
     });
   }
 

toolkit/components/resistfingerprinting/UserCharacteristicsPageService.sys.mjs

@@ -145,13 +145,9 @@ export class UserCharacteristicsPageService {
       return;
     }
     this._initialized = true;
-
-    lazy.console.debug("Init completes");
   }
 
-  shutdown() {
-    lazy.console.debug("shutdown");
-  }
+  shutdown() {}
 
   createContentPage() {
     lazy.console.debug("called createContentPage");
@@ -161,38 +157,51 @@ export class UserCharacteristicsPageService {
         let { promise, resolve } = Promise.withResolvers();
         this._backgroundBrowsers.set(browser, resolve);
 
-        let userCharacteristicsPageURI =
-          Services.io.newURI("https://ritter.vg");
         let principal = Services.scriptSecurityManager.getSystemPrincipal();
         let loadURIOptions = {
           triggeringPrincipal: principal,
         };
+
+        let userCharacteristicsPageURI = Services.io.newURI(
+          "about:fingerprinting"
+        );
+
         browser.loadURI(userCharacteristicsPageURI, loadURIOptions);
 
-        await promise;
+        let data = await promise;
+        if (data.debug) {
+          lazy.console.debug(`Debugging Output:`);
+          for (let line of data.debug) {
+            lazy.console.debug(line);
+          }
+          lazy.console.debug(`(debugging output done)`);
+        }
+        lazy.console.debug(`Data:`, data.output);
+
+        lazy.console.debug("Populating Glean metrics...");
+        // e.g. Glean.characteristics.timezone.set(data.output.foo)
 
         lazy.console.debug("Unregistering actor");
         Services.obs.notifyObservers(
           null,
           "user-characteristics-populating-data-done"
         );
-
-        lazy.console.debug(`Returning`);
       } finally {
-        lazy.console.debug(`In finally`);
         this._backgroundBrowsers.delete(browser);
       }
     });
   }
 
-  async pageLoaded(browsingContext) {
-    lazy.console.debug(`pageLoaded browsingContext=${browsingContext}`);
+  async pageLoaded(browsingContext, data) {
+    lazy.console.debug(
+      `pageLoaded browsingContext=${browsingContext} data=${data}`
+    );
 
     let browser = browsingContext.embedderElement;
 
     let backgroundResolve = this._backgroundBrowsers.get(browser);
     if (backgroundResolve) {
-      backgroundResolve();
+      backgroundResolve(data);
       return;
     }
     throw new Error(`No backround resolve for ${browser} found`);

toolkit/components/resistfingerprinting/content/usercharacteristics.html

@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at https://mozilla.org/MPL/2.0/. -->
+
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8" />
+    <meta
+      http-equiv="Content-Security-Policy"
+      content="default-src 'none'; object-src 'none'; script-src chrome:"
+    />
+    <title>about:fingerprinting</title>
+  </head>
+  <body>
+    <script src="chrome://global/content/usercharacteristics/usercharacteristics.js"></script>
+  </body>
+</html>

toolkit/components/resistfingerprinting/content/usercharacteristics.js

@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+var debugMsgs = [];
+function debug(...args) {
+  let msg = "";
+  if (!args.length) {
+    debugMsgs.push("");
+    return;
+  }
+
+  let stringify = o => {
+    if (typeof o == "string") {
+      return o;
+    }
+    return JSON.stringify(o);
+  };
+
+  let stringifiedArgs = args.map(stringify);
+  msg += stringifiedArgs.join(" ");
+  debugMsgs.push(msg);
+}
+
+debug("Debug Line");
+debug("Another debug line, with", { an: "object" });
+
+let output = {
+  foo: "Hello World",
+};
+
+document.dispatchEvent(
+  new CustomEvent("UserCharacteristicsDataDone", {
+    bubbles: true,
+    detail: {
+      debug: debugMsgs,
+      output,
+    },
+  })
+);

toolkit/components/resistfingerprinting/jar.mn

@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+toolkit.jar:
+  content/global/usercharacteristics/usercharacteristics.html (content/usercharacteristics.html)
+  content/global/usercharacteristics/usercharacteristics.js (content/usercharacteristics.js)

toolkit/components/resistfingerprinting/moz.build

@@ -9,6 +9,8 @@ with Files("**"):
 
 TEST_DIRS += ["tests"]
 
+JAR_MANIFESTS += ["jar.mn"]
+
 UNIFIED_SOURCES += [
     "nsRFPService.cpp",
     "RelativeTimeline.cpp",

toolkit/components/resistfingerprinting/nsIUserCharacteristicsPageService.idl

@@ -9,7 +9,7 @@ webidl BrowsingContext;
 [scriptable, uuid(ce3e9659-e311-49fb-b18b-7f27c6659b23)]
 interface nsIUserCharacteristicsPageService : nsISupports {
 
-    /* (In the next patch, this will:)
+    /*
      * Create the UserCharacteristics about: page as a HiddenFrame
      * and begin the data collection.
      */
@@ -17,6 +17,7 @@ interface nsIUserCharacteristicsPageService : nsISupports {
 
     /*
      * Called when the UserCharacteristics about: page has been loaded
+     * and supplied data back to the actor, which is passed as `data`
      */
-    void pageLoaded(in BrowsingContext browsingContext);
+    void pageLoaded(in BrowsingContext browsingContext, in jsval data);
 };

toolkit/components/resistfingerprinting/nsUserCharacteristics.cpp

@@ -10,12 +10,14 @@
 #include "nsIUserCharacteristicsPageService.h"
 #include "nsServiceManagerUtils.h"
 
-#include "mozilla/Components.h"
 #include "mozilla/Logging.h"
-#include "mozilla/dom/Promise-inl.h"
 #include "mozilla/glean/GleanPings.h"
 #include "mozilla/glean/GleanMetrics.h"
 
+#include "jsapi.h"
+#include "mozilla/Components.h"
+#include "mozilla/dom/Promise-inl.h"
+
 #include "mozilla/StaticPrefs_dom.h"
 #include "mozilla/StaticPrefs_general.h"
 #include "mozilla/StaticPrefs_media.h"
@@ -62,13 +64,23 @@ int MaxTouchPoints() {
 };  // namespace testing
 
 // ==================================================================
-void CanvasStuff() {
+// ==================================================================
+already_AddRefed<mozilla::dom::Promise> ContentPageStuff() {
   nsCOMPtr<nsIUserCharacteristicsPageService> ucp =
       do_GetService("@mozilla.org/user-characteristics-page;1");
   MOZ_ASSERT(ucp);
 
   RefPtr<mozilla::dom::Promise> promise;
-  mozilla::Unused << ucp->CreateContentPage(getter_AddRefs(promise));
+  nsresult rv = ucp->CreateContentPage(getter_AddRefs(promise));
+  if (NS_FAILED(rv)) {
+    MOZ_LOG(gUserCharacteristicsLog, mozilla::LogLevel::Error,
+            ("Could not create Content Page"));
+    return nullptr;
+  }
+  MOZ_LOG(gUserCharacteristicsLog, mozilla::LogLevel::Debug,
+          ("Created Content Page"));
+
+  return promise.forget();
 }
 
 void PopulateCSSProperties() {
@@ -168,6 +180,11 @@ void PopulatePrefs() {
 // the source of the data we are looking at.
 const int kSubmissionSchema = 1;
 
+const auto* const kLastVersionPref =
+    "toolkit.telemetry.user_characteristics_ping.last_version_sent";
+const auto* const kCurrentVersionPref =
+    "toolkit.telemetry.user_characteristics_ping.current_version";
+
 /* static */
 void nsUserCharacteristics::MaybeSubmitPing() {
   MOZ_LOG(gUserCharacteristicsLog, LogLevel::Debug, ("In MaybeSubmitPing()"));
@@ -188,11 +205,6 @@ void nsUserCharacteristics::MaybeSubmitPing() {
    * Sent = Current Version.
    *
    */
-  const auto* const kLastVersionPref =
-      "toolkit.telemetry.user_characteristics_ping.last_version_sent";
-  const auto* const kCurrentVersionPref =
-      "toolkit.telemetry.user_characteristics_ping.current_version";
-
   auto lastSubmissionVersion = Preferences::GetInt(kLastVersionPref, 0);
   auto currentVersion = Preferences::GetInt(kCurrentVersionPref, 0);
 
@@ -216,9 +228,7 @@ void nsUserCharacteristics::MaybeSubmitPing() {
     // currentVersion = -1 is a development value to force a ping submission
     MOZ_LOG(gUserCharacteristicsLog, LogLevel::Debug,
             ("Force-Submitting Ping"));
-    if (NS_SUCCEEDED(PopulateData())) {
-      SubmitPing();
-    }
+    PopulateDataAndEventuallySubmit(false);
     return;
   }
   if (lastSubmissionVersion > currentVersion) {
@@ -237,11 +247,7 @@ void nsUserCharacteristics::MaybeSubmitPing() {
     return;
   }
   if (lastSubmissionVersion < currentVersion) {
-    if (NS_SUCCEEDED(PopulateData())) {
-      if (NS_SUCCEEDED(SubmitPing())) {
-        Preferences::SetInt(kLastVersionPref, currentVersion);
-      }
-    }
+    PopulateDataAndEventuallySubmit(false);
   } else {
     MOZ_ASSERT_UNREACHABLE("Should never reach here");
   }
@@ -251,13 +257,18 @@ const auto* const kUUIDPref =
     "toolkit.telemetry.user_characteristics_ping.uuid";
 
 /* static */
-nsresult nsUserCharacteristics::PopulateData(bool aTesting /* = false */) {
+void nsUserCharacteristics::PopulateDataAndEventuallySubmit(
+    bool aUpdatePref /* = true */, bool aTesting /* = false */
+) {
   MOZ_LOG(gUserCharacteristicsLog, LogLevel::Warning, ("Populating Data"));
   MOZ_ASSERT(XRE_IsParentProcess());
 
   nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
-  NS_ENSURE_TRUE(obs, NS_ERROR_NOT_AVAILABLE);
+  if (!obs) {
+    return;
+  }
 
+  // This notification tells us to register the actor
   obs->NotifyObservers(nullptr, "user-characteristics-populating-data",
                        nullptr);
 
@@ -268,12 +279,17 @@ nsresult nsUserCharacteristics::PopulateData(bool aTesting /* = false */) {
   if (NS_FAILED(rv) || uuidString.Length() == 0) {
     nsCOMPtr<nsIUUIDGenerator> uuidgen =
         do_GetService("@mozilla.org/uuid-generator;1", &rv);
-    NS_ENSURE_SUCCESS(rv, rv);
+    if (NS_FAILED(rv)) {
+      return;
+    }
 
     nsIDToCString id(nsID::GenerateUUID());
     uuidString = id.get();
     Preferences::SetCString(kUUIDPref, uuidString);
   }
+
+  // ------------------------------------------------------------------------
+
   glean::characteristics::client_identifier.Set(uuidString);
 
   glean::characteristics::max_touch_points.Set(testing::MaxTouchPoints());
@@ -281,9 +297,11 @@ nsresult nsUserCharacteristics::PopulateData(bool aTesting /* = false */) {
   if (aTesting) {
     // Many of the later peices of data do not work in a gtest
     // so just populate something, and return
-    return NS_OK;
+    return;
   }
 
+  // ------------------------------------------------------------------------
+
   PopulateMissingFonts();
   PopulateCSSProperties();
   PopulateScreenProperties();
@@ -318,13 +336,47 @@ nsresult nsUserCharacteristics::PopulateData(bool aTesting /* = false */) {
   intl::OSPreferences::GetInstance()->GetSystemLocale(locale);
   glean::characteristics::system_locale.Set(locale);
 
-  return NS_OK;
+  // When this promise resolves, everything succeeded and we can submit.
+  RefPtr<mozilla::dom::Promise> promise = ContentPageStuff();
+
+  // ------------------------------------------------------------------------
+
+  auto fulfillSteps = [aUpdatePref, aTesting](
+                          JSContext* aCx, JS::Handle<JS::Value> aPromiseResult,
+                          mozilla::ErrorResult& aRv) {
+    MOZ_LOG(gUserCharacteristicsLog, mozilla::LogLevel::Debug,
+            ("ContentPageStuff Promise Resolved"));
+
+    nsUserCharacteristics::SubmitPing();
+
+    if (aUpdatePref) {
+      MOZ_LOG(gUserCharacteristicsLog, mozilla::LogLevel::Debug,
+              ("Updating preference"));
+      auto current_version =
+          mozilla::Preferences::GetInt(kCurrentVersionPref, 0);
+      mozilla::Preferences::SetInt(kLastVersionPref, current_version);
+    }
+  };
+
+  // Something failed in the Content Page...
+  auto rejectSteps = [](JSContext* aCx, JS::Handle<JS::Value> aReason,
+                        mozilla::ErrorResult& aRv) {
+    MOZ_LOG(gUserCharacteristicsLog, mozilla::LogLevel::Error,
+            ("ContentPageStuff Promise Rejected"));
+  };
+
+  if (promise) {
+    promise->AddCallbacksWithCycleCollectedArgs(std::move(fulfillSteps),
+                                                std::move(rejectSteps));
+  } else {
+    MOZ_LOG(gUserCharacteristicsLog, mozilla::LogLevel::Error,
+            ("Did not get a Promise back from ContentPageStuff"));
+  }
 }
 
 /* static */
-nsresult nsUserCharacteristics::SubmitPing() {
-  MOZ_LOG(gUserCharacteristicsLog, LogLevel::Warning, ("Submitting Ping"));
+void nsUserCharacteristics::SubmitPing() {
+  MOZ_LOG(gUserCharacteristicsLog, mozilla::LogLevel::Warning,
+          ("Submitting Ping"));
   glean_pings::UserCharacteristics.Submit();
-
-  return NS_OK;
 }

toolkit/components/resistfingerprinting/nsUserCharacteristics.h

@@ -12,9 +12,15 @@ class nsUserCharacteristics {
  public:
   static void MaybeSubmitPing();
 
-  // Public For testing
-  static nsresult PopulateData(bool aTesting = false);
-  static nsresult SubmitPing();
+  /*
+   * These APIs are public only for testing using the gtest
+   * When PopulateDataAndEventuallySubmit is called with aTesting = true
+   *   it will not submit the data, and SubmitPing must be called explicitly.
+   *   This is perfect because that's what we want for the gtest.
+   */
+  static void PopulateDataAndEventuallySubmit(bool aUpdatePref = true,
+                                              bool aTesting = false);
+  static void SubmitPing();
 };
 
 namespace testing {

toolkit/components/resistfingerprinting/tests/gtest/test_usercharping.cpp

@@ -35,7 +35,8 @@ TEST(ResistFingerprinting, UserCharacteristics_Simple)
 
 TEST(ResistFingerprinting, UserCharacteristics_Complex)
 {
-  nsUserCharacteristics::PopulateData(true);
+  nsUserCharacteristics::PopulateDataAndEventuallySubmit(
+      /* aUpdatePref = */ false, /* aTesting = */ true);
 
   bool submitted = false;
   mozilla::glean_pings::UserCharacteristics.TestBeforeNextSubmit(
@@ -102,7 +103,8 @@ TEST(ResistFingerprinting, UserCharacteristics_ClearPref)
                 .value()
                 .get());
       });
-  nsUserCharacteristics::PopulateData(true);
+  nsUserCharacteristics::PopulateDataAndEventuallySubmit(
+      /* aUpdatePref = */ false, /* aTesting = */ true);
   nsUserCharacteristics::SubmitPing();
 
   auto original_value =
@@ -135,7 +137,8 @@ TEST(ResistFingerprinting, UserCharacteristics_ClearPref)
         Preferences::GetCString(kUUIDPref, uuidValue);
         ASSERT_STRNE("", uuidValue.get());
       });
-  nsUserCharacteristics::PopulateData(true);
+  nsUserCharacteristics::PopulateDataAndEventuallySubmit(
+      /* aUpdatePref = */ false, /* aTesting = */ true);
   nsUserCharacteristics::SubmitPing();
 
   Preferences::SetBool("datareporting.healthreport.uploadEnabled",