107 lines
3.5 KiB
JavaScript
107 lines
3.5 KiB
JavaScript
/** \file
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* \brief Wrappers for navigator.deviceMemory property
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*
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* \see https://xhr.spec.whatwg.org/
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*
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* \author Copyright (C) 2019 Libor Polcak
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* \author Copyright (C) 2021 Matus Svancar
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*
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* \license SPDX-License-Identifier: GPL-3.0-or-later
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* \license SPDX-License-Identifier: MPL-2.0
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*/
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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//
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// Alternatively, the contents of this file may be used under the terms
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// of the Mozilla Public License, v. 2.0, as described below:
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at http://mozilla.org/MPL/2.0/.
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//
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// \copyright Copyright (c) 2020 The Brave Authors.
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/** \file
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* This file contains a wrapper for [navigator.deviceMemory](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/deviceMemory).
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* \ingroup wrappers
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*
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* The goal is to prevent fingerprinting by modifying the return value of the `navigator.deviceMemory` parameter.
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*
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* This wrapper operates with three levels of protection:
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*
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* * (0) - return random valid value from range [0.25 - real value]
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* * (1) - return random valid value from range [0.25 - 8]
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* * (2) - return 4
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*
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* These approaches are inspired by the algorithms created by [Brave Software](https://brave.com)
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* available [here](https://github.com/brave/brave-core/blob/master/chromium_src/third_party/blink/renderer/core/frame/navigator_device_memory.cc).
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*
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*/
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/*
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* Create private namespace
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*/
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(function() {
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var wrappers = [
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{
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parent_object: "Navigator.prototype",
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parent_object_property: "deviceMemory",
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wrapped_objects: [],
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helping_code: `
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let dm_prng = alea(domainHash, "navigator.deviceMemory");
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var validValues = [0.25, 0.5, 1.0, 2.0, 4.0, 8.0];
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var ret = 4;
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var realValue = navigator.deviceMemory;
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if(args[0]!=2 && realValue==0.25){
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ret = realValue;
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}
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else if(args[0]==0){
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var maxIndex = validValues.indexOf(realValue);
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if(maxIndex == -1){
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maxIndex = validValues.length-1;
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}
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ret = validValues[Math.floor((dm_prng()*(maxIndex+1)))];
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}
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else if(args[0]==1){
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ret = validValues[Math.floor(dm_prng()*(validValues.length))];
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}
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`,
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post_wrapping_code: [
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{
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code_type: "object_properties",
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parent_object: "Navigator.prototype",
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parent_object_property: "deviceMemory",
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wrapped_objects: [],
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/** \brief replaces navigator.deviceMemory getter
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*
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* Depending on level chosen this property returns:
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* * (0) - random valid value from range [0.25 - real value]
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* * (1) - random valid value from range [0.25 - 8]
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* * (2) - 4
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*/
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wrapped_properties: [
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{
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property_name: "get",
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property_value: `
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function() {
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return ret;
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}`,
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},
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],
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}
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],
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},
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]
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add_wrappers(wrappers);
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})();
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