lbmk/config/firefox/default/patches/0005-canvas-permission.patch.patch

From e0a864992baea169d5f20b366ecdbe918ce1bcba Mon Sep 17 00:00:00 2001
From: LibreWolf Developers <noreply@librewolf.net>
Date: Sun, 6 Sep 2026 10:09:20 +0100
Subject: [PATCH 05/52] canvas-permission.patch

---
 browser/modules/SitePermissions.sys.mjs       | 98 ++++++++++++++++++-
 .../resistfingerprinting/RFPHelper.sys.mjs    | 10 +-
 2 files changed, 105 insertions(+), 3 deletions(-)

diff --git a/browser/modules/SitePermissions.sys.mjs b/browser/modules/SitePermissions.sys.mjs
index 3cf23c809c23..b112014e0d49 100644
--- a/browser/modules/SitePermissions.sys.mjs
+++ b/browser/modules/SitePermissions.sys.mjs
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+import { RFPHelper } from "resource://gre/modules/RFPHelper.sys.mjs";
 
 var gStringBundle = Services.strings.createBundle(
   "chrome://browser/locale/sitePermissions.properties"
@@ -807,6 +808,67 @@ export var SitePermissions = {
         return null;
     }
   },
+
+  /**
+   * Computes whether the canvas image extraction prompt is enabled
+   * based on Baseline/FPP settings and their respective overrides.
+   *
+   * @returns {boolean} true if CanvasImageExtractionPrompt/AllTargets is active
+   */
+  _computeCanvasImageExtractionEnabled() {
+    const fppEnabled = this.fingerprintingProtectionEnabled;
+    const baselineEnabled = this.baselineFingerprintingProtectionEnabled;
+
+    if (fppEnabled) {
+      const defaults = RFPHelper.getTargetDefaults();
+      const active = new Set(defaults);
+      const overrides = this.fingerprintingProtectionOverrides;
+      this._applyOverrides(active, overrides);
+      if (active.has("CanvasImageExtractionPrompt")) {
+        return true;
+      }
+    }
+
+    if (baselineEnabled) {
+      const defaults = RFPHelper.getTargetDefaultsBaseline();
+      const active = new Set(defaults);
+      const overrides = this.baselineFingerprintingProtectionOverrides;
+      this._applyOverrides(active, overrides);
+      if (active.has("CanvasImageExtractionPrompt")) {
+        return true;
+      }
+    }
+
+    return false;
+  },
+
+  /**
+   * Applies override flags to an active set of targets.
+   *
+   * @param {Set} active - The active targets set
+   * @param {string} overridesString - The override string (e.g., "+CanvasImageExtractionPrompt,+AllTargets")
+   */
+  _applyOverrides(active, overridesString) {
+    for (const flag of overridesString.split(",").filter(Boolean)) {
+      if (flag.startsWith("+")) {
+        const target = flag.slice(1);
+        if (
+          target === "AllTargets" ||
+          target === "CanvasImageExtractionPrompt"
+        ) {
+          active.add("CanvasImageExtractionPrompt");
+        }
+      } else if (flag.startsWith("-")) {
+        const target = flag.slice(1);
+        if (
+          target === "AllTargets" ||
+          target === "CanvasImageExtractionPrompt"
+        ) {
+          active.delete("CanvasImageExtractionPrompt");
+        }
+      }
+    }
+  },
 };
 
 let gPermissions = {
@@ -1069,7 +1131,10 @@ let gPermissions = {
 
     canvas: {
       get disabled() {
-        return !SitePermissions.resistFingerprinting;
+        return (
+          !SitePermissions.resistFingerprinting &&
+          !SitePermissions._computeCanvasImageExtractionEnabled()
+        );
       },
     },
 
@@ -1133,6 +1198,37 @@ XPCOMUtils.defineLazyPreferenceGetter(
   false,
   SitePermissions.invalidatePermissionList.bind(SitePermissions)
 );
+XPCOMUtils.defineLazyPreferenceGetter(
+  SitePermissions,
+  "fingerprintingProtectionEnabled",
+  "privacy.fingerprintingProtection",
+  false,
+  SitePermissions.invalidatePermissionList.bind(SitePermissions)
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  SitePermissions,
+  "fingerprintingProtectionOverrides",
+  "privacy.fingerprintingProtection.overrides",
+  "",
+  SitePermissions.invalidatePermissionList.bind(SitePermissions)
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  SitePermissions,
+  "baselineFingerprintingProtectionEnabled",
+  "privacy.baselineFingerprintingProtection",
+  false,
+  SitePermissions.invalidatePermissionList.bind(SitePermissions)
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  SitePermissions,
+  "baselineFingerprintingProtectionOverrides",
+  "privacy.baselineFingerprintingProtection.overrides",
+  "",
+  SitePermissions.invalidatePermissionList.bind(SitePermissions)
+);
 
 XPCOMUtils.defineLazyPreferenceGetter(
   SitePermissions,
diff --git a/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs b/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs
index f82d7309e129..d11f8a011fac 100644
--- a/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs
+++ b/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs
@@ -208,8 +208,14 @@ class _RFPHelper {
       return;
     }
 
-    let loadContext = notificationCallbacks.getInterface(Ci.nsILoadContext);
-    if (!loadContext || !loadContext.isContent) {
+    let loadContext;
+    try {
+      loadContext = notificationCallbacks.getInterface(Ci.nsILoadContext);
+    } catch (e) {
+      return;
+    }
+
+    if (!loadContext.isContent) {
       return;
     }
 
-- 
2.47.3