Updated extensions:

 * Upgraded Privacy Redirect to 1.1.49 and configured to use the 10 most reliable invidious instances
 * Removed ViewTube
 * Added torproxy@icecat.gnu based on 'Proxy toggle' extension
 * Added jShelter 0.11.1
 * Upgraded LibreJS to 7.21.0
 * Upgraded HTTPS Everywhere to 2021.7.13
 * Upgraded SubmitMe to 1.9

1 files changed, 136 insertions, 0 deletions

diff --git a/data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js b/data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js
new file mode 100644
index 0000000..a61b617
--- /dev/null
+++ b/data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js
@@ -0,0 +1,136 @@
+/** \file
+ * \brief Wrappers for Generic Sensor API
+ *
+ * \see https://www.w3.org/TR/generic-sensor/
+ *
+ *  \author Copyright (C) 2021  Radek Hranicky
+ *
+ *  \license SPDX-License-Identifier: GPL-3.0-or-later
+ */
+//
+//  This program is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+/** \file
+ * \ingroup wrappers
+ *
+ * MOTIVATION
+ * The risk of using Generic Sensor API calls for device fingerprinting is
+ * mentioned within the W3C Candidate Recommendation Draft, 29 July 2021
+ * (https://www.w3.org/TR/2021/CRD-generic-sensor-20210729/#device-fingerprinting)
+ * Documented threats include manufacturing imperfections and differences
+ * that are unique to the concrete model of the device and can be used
+ * for fingerprinting.
+ *
+ * We discovered another loophole in the `Sensor.timestamp` attribute. The value
+ * describes when the last `Sensor.onreading` event occurred, in millisecond precision.
+ * We observed the time origin is not the time of browsing context creation
+ * but the last boot time of the device. Exposing such information is dangerous
+ * as it allows to fingerprint the user easily. It is unlikely that two different
+ * devices will boot at exactly the same time.
+ *
+ * Tested with the Magnetometer sensor on the following devices:
+ * - Samsung Galaxy S21 Ultra; Android 11, kernel 5.4.6-215566388-abG99BXXU3AUE1, Build/RP1A.200720.012.G998BXXU3AUE1
+ *   Chrome 94.0.4606.71 and Kiwi (Chromium) 94.0.4606.56
+ * - Xiaomi Redmi Note 5; Android 9, kernel 4.4.156-perf+, Build/9 PKQ1.180901.001
+ *   Chrome 94.0.4606.71
+ *
+ *
+ * WRAPPING
+ *
+ * The wrapper thus protects device by changing the time origin to the browsing context
+ * creation time, whereas the timestamp should still uniquely identify the reading.
+ * This is achieved in the following way:
+ * - At the first reading, we calculate the difference between the original value
+ *   and performance.now(). This gives us the offset between 1) the device boot
+ *   and 2) the page context initialization.
+ * - On every reading, the offset is subtracted from the original value. The resulting
+ *   value then uniquely identifies the reading sample without exposing the boot time.
+ * - Like in the other time precision wrappers, the resulting timestamp is processed
+ *   by the mitigation function before return. The mitigation may round and (optionally)
+ *   add noise to the resulting timestamp.
+ *
+ *
+ * POSSIBLE IMPROVEMENTS
+ * in protection level 2, the timestamp origin may be set to a random value based
+ * on the session hash. This can serve as a "fake boot time."
+ */
+
+ /*
+  * Create private namespace
+  */
+ (function() {
+
+  var remember_past_values = `var precision = args[0];
+ 				var doNoise = args[1];
+ 				var pastValues = {};
+ 				${rounding_function}
+ 				${noise_function}
+ 				var mitigationF = rounding_function;
+ 				if (doNoise === true){
+ 					mitigationF = function(value, precision) {
+ 						let params = [value, precision];
+ 						if (params in pastValues) {
+ 							return pastValues[params];
+ 						}
+ 						let result = noise_function(...params);
+ 						pastValues[params] = result;
+ 						return result;
+ 					}
+ 				}
+ 				var offsetCompStartPageStart = undefined;
+ 			`;
+
+ 	var wrappers = [
+ 		{
+ 			/**
+ 			 * \see https://dom.spec.whatwg.org/#ref-for-dom-event-timestamp%E2%91%A0
+ 			 */
+ 			parent_object: "Sensor.prototype",
+ 			parent_object_property: "timestamp",
+ 			wrapped_objects: [],
+ 			helping_code: remember_past_values + `let origGet = Object.getOwnPropertyDescriptor(Sensor.prototype, "timestamp").get`,
+ 			post_wrapping_code: [
+ 				{
+ 					code_type: "object_properties",
+ 					parent_object: "Sensor.prototype",
+ 					parent_object_property: "timestamp",
+ 					wrapped_objects: [],
+ 					/**  \brief replaces Sensor.prototype.timestamp getter to create
+ 					 * a timestamp with the desired precision.
+ 					 */
+ 					wrapped_properties: [
+ 						{
+ 							property_name: "get",
+ 							property_value: `
+                function() {
+                  orig_val = origGet.call(this);
+                  if (typeof orig_val != 'number') {
+                    // Sensor is not available or there is no reading yet.
+                    return orig_val;
+                  }
+									if (offsetCompStartPageStart === undefined) {
+                    // The offset has not been set yet so it needs to be calculated.
+										offsetCompStartPageStart = orig_val - performance.now();
+									}
+									return mitigationF(orig_val - offsetCompStartPageStart, precision);
+								}`,
+ 						},
+ 					],
+ 				}
+ 			],
+ 		},
+ 	]
+ 	add_wrappers(wrappers);
+ })()