Bug 1838856 - Add a telemetry for measuring the calculating time of canvas random noises. r=tjr

Differential Revision: https://phabricator.services.mozilla.com/D181574

toolkit/components/glean/metrics_index.py

@@ -27,6 +27,7 @@ gecko_metrics = [
     "toolkit/components/extensions/metrics.yaml",
     "toolkit/components/glean/metrics.yaml",
     "toolkit/components/pdfjs/metrics.yaml",
+    "toolkit/components/resistfingerprinting/metrics.yaml",
     "toolkit/mozapps/extensions/metrics.yaml",
     "toolkit/components/processtools/metrics.yaml",
     "toolkit/components/translations/metrics.yaml",

toolkit/components/resistfingerprinting/metrics.yaml

@@ -0,0 +1,27 @@
+# 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 http://mozilla.org/MPL/2.0/.
+
+# Adding a new metric? We have docs for that!
+# https://firefox-source-docs.mozilla.org/toolkit/components/glean/user/new_definitions_file.html
+
+$schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
+$tags:
+  - 'Core :: Privacy: Anti-Tracking'
+
+fingerprinting.protection:
+  canvas_noise_calculate_time:
+    type: timing_distribution
+    time_unit: millisecond
+    description: >
+      Counts how long to generate canvas random noises.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1838856
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1838856#c1
+    notification_emails:
+      - tihuang@mozilla.com
+      - tom@mozilla.com
+      - tschuster@mozilla.com
+    expires: never
+    telemetry_mirror: FINGERPRINTING_PROTECTION_CANVAS_NOISE_CALCULATE_TIME_MS

toolkit/components/resistfingerprinting/nsRFPService.cpp

@@ -24,6 +24,7 @@
 #include "mozilla/Atomics.h"
 #include "mozilla/Casting.h"
 #include "mozilla/ClearOnShutdown.h"
+#include "mozilla/glean/GleanMetrics.h"
 #include "mozilla/HashFunctions.h"
 #include "mozilla/HelperMacros.h"
 #include "mozilla/Likely.h"
@@ -1296,10 +1297,17 @@ nsresult nsRFPService::RandomizePixels(nsICookieJarSettings* aCookieJarSettings,
     return NS_OK;
   }
 
+  auto timerId =
+      glean::fingerprinting_protection::canvas_noise_calculate_time.Start();
+
   nsTArray<uint8_t> canvasKey;
   nsresult rv = GenerateCanvasKeyFromImageData(aCookieJarSettings, aData, aSize,
                                                canvasKey);
-  NS_ENSURE_SUCCESS(rv, rv);
+  if (NS_FAILED(rv)) {
+    glean::fingerprinting_protection::canvas_noise_calculate_time.Cancel(
+        std::move(timerId));
+    return rv;
+  }
 
   // Calculate the number of pixels based on the given data size. One pixel uses
   // 4 bytes that contains ARGB information.
@@ -1352,5 +1360,8 @@ nsresult nsRFPService::RandomizePixels(nsICookieJarSettings* aCookieJarSettings,
     aData[idx] = aData[idx] ^ (bit & 0x1);
   }
 
+  glean::fingerprinting_protection::canvas_noise_calculate_time
+      .StopAndAccumulate(std::move(timerId));
+
   return NS_OK;
 }

toolkit/components/resistfingerprinting/tests/browser/browser_canvas_randomization.js

@@ -510,6 +510,10 @@ async function runTest(enabled) {
 
   for (let test of TEST_CASES) {
     info(`Testing ${test.name}`);
+
+    // Clear telemetry before starting test.
+    Services.fog.testResetFOG();
+
     let data = await test.extractCanvasData(tab.linkedBrowser);
     let result = test.isDataRandomized(data[0], test.originalData);
 
@@ -549,6 +553,17 @@ async function runTest(enabled) {
         enabled ? "different" : "the same"
       }.`
     );
+
+    // Verify the telemetry is recorded if canvas randomization is enabled.
+    if (enabled) {
+      await Services.fog.testFlushAllChildren();
+
+      ok(
+        Glean.fingerprintingProtection.canvasNoiseCalculateTime.testGetValue()
+          .sum > 0,
+        "The telemetry of canvas randomization is recorded."
+      );
+    }
   }
 
   BrowserTestUtils.removeTab(tab);

toolkit/components/resistfingerprinting/tests/browser/browser_canvas_randomization_worker.js

@@ -235,6 +235,10 @@ async function runTest(enabled) {
 
   for (let test of TEST_CASES) {
     info(`Testing ${test.name} in the worker`);
+
+    // Clear telemetry before starting test.
+    Services.fog.testResetFOG();
+
     let data = await await runFunctionInWorker(
       tab.linkedBrowser,
       test.extractCanvasData
@@ -282,6 +286,17 @@ async function runTest(enabled) {
     );
   }
 
+  // Verify the telemetry is recorded if canvas randomization is enabled.
+  if (enabled) {
+    await Services.fog.testFlushAllChildren();
+
+    ok(
+      Glean.fingerprintingProtection.canvasNoiseCalculateTime.testGetValue()
+        .sum > 0,
+      "The telemetry of canvas randomization is recorded."
+    );
+  }
+
   BrowserTestUtils.removeTab(tab);
   BrowserTestUtils.removeTab(privateTab);
   await BrowserTestUtils.closeWindow(privateWindow);

toolkit/components/telemetry/Histograms.json

@@ -663,6 +663,21 @@
     "releaseChannelCollection": "opt-out",
     "description": "GPU Device Reset Reason (ok, hung, removed, reset, internal error, invalid call, out of memory)"
   },
+  "FINGERPRINTING_PROTECTION_CANVAS_NOISE_CALCULATE_TIME_MS": {
+    "record_in_processes": ["content"],
+    "products": ["firefox"],
+    "alert_emails": [
+      "tihuang@mozilla.com",
+      "tom@mozilla.com",
+      "tschuster@mozilla.com"
+    ],
+    "expires_in_version": "never",
+    "bug_numbers": [1838856],
+    "kind": "exponential",
+    "high": 600000,
+    "n_buckets": 100,
+    "description": "Counts how long to generate canvas random noises."
+  },
   "FORCED_DEVICE_RESET_REASON": {
     "record_in_processes": ["main", "content", "gpu"],
     "products": ["firefox", "fennec"],