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Diffstat (limited to 'data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js')
| -rw-r--r-- | data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js | 136 |
1 files changed, 0 insertions, 136 deletions
diff --git a/data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js b/data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js deleted file mode 100644 index a61b617..0000000 --- a/data/extensions/jsr@javascriptrestrictor/wrappingS-SENSOR.js +++ /dev/null @@ -1,136 +0,0 @@ -/** \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); - })() |