From fa5c0b073214191e6996ba0b5bc8e61560ff822c Mon Sep 17 00:00:00 2001
From: Mark H Weaver <mhw@netris.org>
Date: Wed, 27 Sep 2023 00:53:30 -0400
Subject: Update the JShelter extension to 0.15.2.

---
 .../jsr@javascriptrestrictor/wrappingS-NP.js       | 79 +++++++++++++++-------
 1 file changed, 55 insertions(+), 24 deletions(-)

(limited to 'data/extensions/jsr@javascriptrestrictor/wrappingS-NP.js')

diff --git a/data/extensions/jsr@javascriptrestrictor/wrappingS-NP.js b/data/extensions/jsr@javascriptrestrictor/wrappingS-NP.js
index 018eaee..4bcd333 100644
--- a/data/extensions/jsr@javascriptrestrictor/wrappingS-NP.js
+++ b/data/extensions/jsr@javascriptrestrictor/wrappingS-NP.js
@@ -47,6 +47,19 @@
  * These approaches are inspired by the algorithms created by [Brave Software](https://brave.com)
  * available [here](https://github.com/brave/brave-core/blob/master/chromium_src/third_party/blink/renderer/modules/plugins/dom_plugin_array.cc).
  *
+ * The purpose of the wrappers is solely to prevent fingerprinting. However,
+ * browsers modyfing the array stand out of the crowd, which makes them more
+ * fingerprintable. Consequently, JShelter does not modify an empty list. So
+ * no matter the configuration, an empty list is not populated by the wrappers.
+ *
+ *  If PDF inline viewing is supported, Firefox returns 5 plugins:
+ *    * "PDF Viewer"
+ *    * "Chrome PDF Viewer"
+ *    * "Chromium PDF Viewer"
+ *    * "Microsoft Edge PDF Viewer"
+ *    * "WebKit built-in PDF"
+ *
+ *  A list containing exactly these plugins is treated as the empty list and it is not modified.
  */
 
 /*
@@ -269,36 +282,54 @@
 		{
 			parent_object: "Navigator.prototype",
 			parent_object_property: "plugins",
-			apply_if: "navigator.plugins.length > 0",
+			apply_if: "applyWrapper",
 			wrapped_objects: [],
 			helping_code:
 				methods + farbles + fakes +`
-				var fp_prng = alea(domainHash, "S-NP");
-				var plugins = navigator.plugins;
-				var buffer = [];
-				if(args[0]==0){
-					for(var i = 0;i<plugins.length;i++){
-						buffer.push(farblePlugin(plugins[i]), fp_prng);
-					}
+				var applyWrapper = true; // Possibly overridden below
+				if (navigator.plugins.length === 0) {
+					applyWrapper = false;
 				}
-				if(args[0]==1){
-					for(var i = 0;i<plugins.length;i++){
-						buffer.push(plugins[i]);
+				if (navigator.plugins.length === 5) {
+					let plugins = Array.prototype.reduce.call(
+							navigator.plugins,
+							function (acc, o) {acc.push(o.name); return acc;}, []);
+					if (plugins.includes("PDF Viewer") &&
+							plugins.includes("Chrome PDF Viewer") &&
+							plugins.includes("Chromium PDF Viewer") &&
+							plugins.includes("Microsoft Edge PDF Viewer") &&
+							plugins.includes( "WebKit built-in PDF")) {
+						applyWrapper = false; // See https://developer.mozilla.org/en-US/docs/Web/API/Navigator/plugins
 					}
-					shuffleArray(buffer);
-				}
-				if(args[0]==0 || args[0]==1){
-					var fakePlugin1 = fakePlugin(32, 16, 8);
-					var fakePlugin2 = fakePlugin(31, 15, 7);
-					buffer.push(fakePlugin1, fakePlugin2);
-					shuffleArray(buffer);
-				}
-				var fakePluginArray = fakePluginArrayF(buffer);
-				if(args[0]==1 || args[0]==2){
-					var fakeMimeTypeArray = fakeMimeTypeArrayF([]);
 				}
-				else {
-					var fakeMimeTypeArray = fakeMimeTypeArrayF(fakePluginArray);
+				if (applyWrapper) {
+					var fp_prng = alea(domainHash, "S-NP");
+					var plugins = navigator.plugins;
+					var buffer = [];
+					if(args[0]==0){
+						for(var i = 0;i<plugins.length;i++){
+							buffer.push(farblePlugin(plugins[i], fp_prng));
+						}
+					}
+					if(args[0]==1){
+						for(var i = 0;i<plugins.length;i++){
+							buffer.push(plugins[i]);
+						}
+						shuffleArray(buffer);
+					}
+					if(args[0]==0 || args[0]==1){
+						var fakePlugin1 = fakePlugin(32, 16, 8);
+						var fakePlugin2 = fakePlugin(31, 15, 7);
+						buffer.push(fakePlugin1, fakePlugin2);
+						shuffleArray(buffer);
+					}
+					var fakePluginArray = fakePluginArrayF(buffer);
+					if(args[0]==1 || args[0]==2){
+						var fakeMimeTypeArray = fakeMimeTypeArrayF([]);
+					}
+					else {
+						var fakeMimeTypeArray = fakeMimeTypeArrayF(fakePluginArray);
+					}
 				}
 			`,
 			post_wrapping_code: [
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