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Delta Between Two Patch Sets: lib/content/snippets.js

Issue 29886700: Issue 6969 - Implement abort-on-property-read snippet (Closed) Base URL: https://hg.adblockplus.org/adblockpluscore/
Left Patch Set: Minor style changes Created Oct. 3, 2018, 10:19 p.m.
Right Patch Set: Another round of changes Created Oct. 31, 2018, 8:43 p.m.
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1 /* 1 /*
2 * This file is part of Adblock Plus <https://adblockplus.org/>, 2 * This file is part of Adblock Plus <https://adblockplus.org/>,
3 * Copyright (C) 2006-present eyeo GmbH 3 * Copyright (C) 2006-present eyeo GmbH
4 * 4 *
5 * Adblock Plus is free software: you can redistribute it and/or modify 5 * Adblock Plus is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 3 as 6 * it under the terms of the GNU General Public License version 3 as
7 * published by the Free Software Foundation. 7 * published by the Free Software Foundation.
8 * 8 *
9 * Adblock Plus is distributed in the hope that it will be useful, 9 * Adblock Plus is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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485 (!re || re.test(target.textContent))) 485 (!re || re.test(target.textContent)))
486 { 486 {
487 event.preventDefault(); 487 event.preventDefault();
488 } 488 }
489 }, 489 },
490 true); 490 true);
491 } 491 }
492 492
493 exports["prevent-inline-scripts"] = preventInlineScripts; 493 exports["prevent-inline-scripts"] = preventInlineScripts;
494 494
495 /**
496 * Generates a random alphanumeric ID consisting of 6 base-36 digits
497 * from the range 100000..zzzzzz (both inclusive).
498 *
499 * @returns {string} The random ID.
500 */
495 function randomId() 501 function randomId()
496 { 502 {
497 // 2176782336 is 36^6 which mean 6 chars [a-z0-9] 503 // 2176782336 is 36^6 which mean 6 chars [a-z0-9]
498 // 60466176 is 36^5 504 // 60466176 is 36^5
499 // 2176782336 - 60466176 = 2116316160. This ensure always 6 chars 505 // 2176782336 - 60466176 = 2116316160. This ensure to always have 6
500 // for when Math.random() returns 0.0 506 // chars even if Math.random() returns its minimum value 0.0
507 //
501 return Math.floor(Math.random() * 2116316160 + 60466176).toString(36); 508 return Math.floor(Math.random() * 2116316160 + 60466176).toString(36);
502 } 509 }
503 510
504 /** 511 function wrapPropertyAccess(object, property, descriptor)
505 * Will patch a property on the window object to abort when read. 512 {
506 * It will intercept the onerror callback and block it if tagged. 513 let currentDescriptor = Object.getOwnPropertyDescriptor(object, property);
507 * 514 if (currentDescriptor && !currentDescriptor.configurable)
508 * @todo handle properties of properties. 515 return false;
509 * 516
510 * @param {string} prop the name of the property. 517 Object.defineProperty(object, property, descriptor);
511 */ 518 return true;
512 function abortOnPropertyRead(prop) 519 }
513 { 520
514 if (!prop) 521 /**
522 * Patches a property on the window object to abort execution when the
523 * property is read.
524 *
525 * No error is be printed to the console.
526 *
527 * The idea originates from
528 * {@link https://github.com/uBlockOrigin/uAssets/blob/80b195436f8f8d78ba713237b fc268ecfc9d9d2b/filters/resources.txt#L1703 uBlock Origin}.
529 *
530 * @param {string} property The name of the property.
531 */
532 function abortOnPropertyRead(property)
533 {
534 if (!property)
515 return; 535 return;
516 536
517 let rid = randomId(); 537 let rid = randomId();
518 538
519 function canceller() 539 function abort()
520 { 540 {
521 throw new ReferenceError(rid); 541 throw new ReferenceError(rid);
522 } 542 }
523 543
524 let {onerror} = window; 544 let {onerror} = window;
525 window.onerror = (message, ...rest) => 545 if (wrapPropertyAccess(window, property, {get: abort, set() {}}))
526 { 546 {
527 if (typeof message == "string" && message.includes(rid)) 547 window.onerror = (message, ...rest) =>
528 return true; 548 {
529 if (onerror && typeof onerror == "function") 549 if (typeof message == "string" && message.includes(rid))
530 return onerror(this, message, ...rest); 550 return true;
Manish Jethani 2018/10/23 15:31:24 This needs to be onerror.call
hub 2018/10/23 18:23:17 Done.
531 }; 551 if (typeof onerror == "function")
532 552 return (() => {}).call.call(onerror, this, message, ...rest);
533 (function(o, p) 553 };
Manish Jethani 2018/10/23 15:31:24 I think this should be a separate function: fun
hub 2018/10/23 18:23:17 Done.
534 { 554 }
535 // simple property 555 }
536 let d = Object.getOwnPropertyDescriptor(o, p); 556
537 if (!d || d.get != canceller) 557 exports["abort-on-property-read"] = makeInjector(abortOnPropertyRead,
538 Object.defineProperty(o, p, {get: canceller, set() {}}); 558 wrapPropertyAccess,
539 })(window, prop); 559 randomId);
540 }
541
542 exports["abort-on-property-read"] = makeInjector(abortOnPropertyRead, randomId);
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