tor-browser

commit a80c99ed577d91c78909f004a347563898338a53
parent cd9bb28c070b2873ad77a3d96456ce686b052e68
Author: Tom Ritter <tom@mozilla.com>
Date:   Mon, 29 Dec 2025 20:28:59 +0000

Bug 2005866: Collect more detailed Math operation data r=timhuang

Differential Revision: https://phabricator.services.mozilla.com/D276713

Diffstat:
M
toolkit/components/resistfingerprinting/UserCharacteristicsPageService.sys.mjs
 | 
80
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
toolkit/components/resistfingerprinting/metrics.yaml
 | 
20
++++++++++++++++++++

2 files changed, 100 insertions(+), 0 deletions(-)
diff --git a/toolkit/components/resistfingerprinting/UserCharacteristicsPageService.sys.mjs b/toolkit/components/resistfingerprinting/UserCharacteristicsPageService.sys.mjs
@@ -158,6 +158,7 @@ export class UserCharacteristicsPageService {
       [this.populateZoomPrefs, []],
       [this.populateDisabledMediaPrefs, []],
       [this.populateMathOps, []],
+      [this.populateMathOpsFdlibm2, []],
       [this.populateMappableData, [data.output]],
       [this.populateGamepads, [data.gamepads]],
       [this.populateClientInfo, []],
@@ -724,6 +725,85 @@ export class UserCharacteristicsPageService {
     }
   }
 
+  async populateMathOpsFdlibm2() {
+    // IF YOU ADD ENTRIES TO THIS LIST, PLEASE ALSO UPDATE THE COUNT IN
+    // toolkit/components/resistfingerprinting/tests/browser/browser_usercharacteristics_math.js
+    const getResults = () => {
+      const results = [];
+
+      // Math constants
+      results.push(Math.PI);
+      results.push(Math.E);
+      results.push(Math.SQRT2);
+      results.push(Math.SQRT1_2);
+      results.push(Math.LN2);
+      results.push(Math.LN10);
+      results.push(Math.LOG2E);
+      results.push(Math.LOG10E);
+
+      // Intermediate values from operation 15: Math.pow(Math.PI, -100)
+      results.push(Math.pow(Math.PI, -100));
+
+      // Intermediate values from operation 16: Math.log(1e154 + Math.sqrt(1e154^2 - 1))
+      const v16 = 1e154;
+      results.push(v16);
+      results.push(v16 * v16);
+      const sqrt16 = Math.sqrt(v16 * v16 - 1);
+      results.push(sqrt16);
+      results.push(v16 + sqrt16);
+
+      // Intermediate values from operation 17: Math.log(1 + Math.sqrt(2))
+      const sqrt2 = Math.sqrt(2);
+      results.push(sqrt2);
+      results.push(1 + sqrt2);
+
+      // Intermediate values from operation 18: Math.log((1 + 0.5) / (1 - 0.5)) / 2
+      results.push(1 + 0.5);
+      results.push(1 - 0.5);
+      results.push((1 + 0.5) / (1 - 0.5));
+
+      // Intermediate values from operation 19: Math.exp(1) - 1 / Math.exp(1) / 2
+      const exp1 = Math.exp(1);
+      results.push(exp1);
+      results.push(1 / exp1);
+      results.push(1 / exp1 / 2);
+      results.push(exp1 - 1 / exp1 / 2);
+
+      // Intermediate values from operation 20: (Math.exp(1) + 1 / Math.exp(1)) / 2
+      results.push(exp1 + 1 / exp1);
+      results.push((exp1 + 1 / exp1) / 2);
+
+      // Intermediate values from operation 21: Math.exp(1) - 1
+      results.push(exp1 - 1);
+
+      // Intermediate values from operation 22: (Math.exp(2) - 1) / (Math.exp(2) + 1)
+      const exp2 = Math.exp(2);
+      results.push(exp2);
+      results.push(exp2 - 1);
+      results.push(exp2 + 1);
+      results.push((exp2 - 1) / (exp2 + 1));
+
+      // Intermediate values from operation 23: Math.log(1 + 10)
+      results.push(1 + 10);
+
+      // Additional illustrative values
+      results.push(Math.sqrt(3));
+      results.push(Math.sqrt(5));
+      results.push(Math.pow(2, 0.5));
+      results.push(Math.pow(Math.E, 2));
+      results.push(Math.log(Math.E));
+      results.push(Math.log(10));
+
+      return results;
+    };
+
+    const sandbox = Cu.Sandbox(null, {
+      alwaysUseFdlibm: true,
+    });
+    const results = Cu.evalInSandbox(`(${getResults.toString()})()`, sandbox);
+    Glean.characteristics.mathOpsFdlibm2.set(JSON.stringify(results));
+  }
+
   async populateClientInfo() {
     const buildID = Services.appinfo.appBuildID;
     const buildDate =
diff --git a/toolkit/components/resistfingerprinting/metrics.yaml b/toolkit/components/resistfingerprinting/metrics.yaml
@@ -3415,6 +3415,26 @@ characteristics:
       # is more like 'technical' (per the Data Review), I'm marking highly sensitive.
       - highly_sensitive
 
+  math_ops_fdlibm_2:
+    type: text
+    description: >
+      Result of additional fingerprintable math operations, with fdlibm enabled
+    lifetime: application
+    send_in_pings:
+      - user-characteristics
+    notification_emails:
+      - tom@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1879151
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=2005866
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=2005866
+    expires: never
+    data_sensitivity:
+      # Text metrics are _required_ to be web_activity or highly_sensitive, so even though this
+      # is more like 'technical' (per the Data Review), I'm marking highly sensitive.
+      - highly_sensitive
+
   keyboard_layout:
     type: string
     description: >