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Diffstat (limited to 'data/extensions/jsr@javascriptrestrictor/wrappingS-DM.js')
| -rw-r--r-- | data/extensions/jsr@javascriptrestrictor/wrappingS-DM.js | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/data/extensions/jsr@javascriptrestrictor/wrappingS-DM.js b/data/extensions/jsr@javascriptrestrictor/wrappingS-DM.js new file mode 100644 index 0000000..2df5996 --- /dev/null +++ b/data/extensions/jsr@javascriptrestrictor/wrappingS-DM.js @@ -0,0 +1,107 @@ +/** \file + * \brief Wrappers for navigator.deviceMemory property + * + * \see https://xhr.spec.whatwg.org/ + * + * \author Copyright (C) 2019 Libor Polcak + * \author Copyright (C) 2021 Matus Svancar + * + * \license SPDX-License-Identifier: GPL-3.0-or-later + * \license SPDX-License-Identifier: MPL-2.0 + */ +// +// 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/>. +// +// Alternatively, the contents of this file may be used under the terms +// of the Mozilla Public License, v. 2.0, as described below: +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this file, +// You can obtain one at http://mozilla.org/MPL/2.0/. +// +// \copyright Copyright (c) 2020 The Brave Authors. + +/** \file + * This file contains a wrapper for [navigator.deviceMemory](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/deviceMemory). + * \ingroup wrappers + * + * The goal is to prevent fingerprinting by modifying the return value of the `navigator.deviceMemory` parameter. + * + * This wrapper operates with three levels of protection: + * + * * (0) - return random valid value from range [0.25 - real value] + * * (1) - return random valid value from range [0.25 - 8] + * * (2) - return 4 + * + * 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/core/frame/navigator_device_memory.cc). + * + */ + +/* + * Create private namespace + */ +(function() { + var wrappers = [ + { + parent_object: "Navigator.prototype", + parent_object_property: "deviceMemory", + wrapped_objects: [], + helping_code: ` + let dm_prng = alea(domainHash, "navigator.deviceMemory"); + var validValues = [0.25, 0.5, 1.0, 2.0, 4.0, 8.0]; + var ret = 4; + var realValue = navigator.deviceMemory; + if(args[0]!=2 && realValue==0.25){ + ret = realValue; + } + else if(args[0]==0){ + var maxIndex = validValues.indexOf(realValue); + if(maxIndex == -1){ + maxIndex = validValues.length-1; + } + ret = validValues[Math.floor((dm_prng()*(maxIndex+1)))]; + } + else if(args[0]==1){ + ret = validValues[Math.floor(dm_prng()*(validValues.length))]; + } + `, + post_wrapping_code: [ + { + code_type: "object_properties", + parent_object: "Navigator.prototype", + parent_object_property: "deviceMemory", + wrapped_objects: [], + /** \brief replaces navigator.deviceMemory getter + * + * Depending on level chosen this property returns: + * * (0) - random valid value from range [0.25 - real value] + * * (1) - random valid value from range [0.25 - 8] + * * (2) - 4 + */ + wrapped_properties: [ + { + property_name: "get", + property_value: ` + function() { + return ret; + }`, + }, + ], + } + ], + }, + ] + add_wrappers(wrappers); +})(); |