ematrix/js/cookies.js

/*******************************************************************************

    ηMatrix - a browser extension to black/white list requests.
    Copyright (C) 2013-2019 Raymond Hill
    Copyright (C) 2019-2022 Alessio Vanni

    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 {http://www.gnu.org/licenses/}.

    Home: https://gitlab.com/vannilla/ematrix
    uMatrix Home: https://github.com/gorhill/uMatrix
*/

// rhill 2013-12-14: the whole cookie management has been rewritten so as
// to avoid having to call chrome API whenever a single cookie changes, and
// to record cookie for a web page *only* when its value changes.
// https://github.com/gorhill/httpswitchboard/issues/79

"use strict";

// Isolate from global namespace

// Use cached-context approach rather than object-based approach, as details
// of the implementation do not need to be visible

ηMatrix.cookieHunter = (function () {
    Cu.import('chrome://ematrix/content/lib/UriTools.jsm');
    Cu.import('chrome://ematrix/content/lib/CookieCache.jsm');

    let ηm = ηMatrix;

    let recordPageCookiesQueue = new Map();
    let removePageCookiesQueue = new Map();
    let removeCookieQueue = new Set();
    let processRemoveQueuePeriod = 2 * 60 * 1000;
    let processCleanPeriod = 10 * 60 * 1000;
    let processPageRecordQueueTimer = null;
    let processPageRemoveQueueTimer = null;

    // Look for cookies to record for a specific web page

    let recordPageCookiesAsync = function (pageStats) {
	// Store the page stats objects so that it doesn't go away
	// before we handle the job.
	// rhill 2013-10-19: pageStats could be nil, for example, this can
	// happens if a file:// ... makes an xmlHttpRequest
	if (!pageStats) {
            return;
	}
	recordPageCookiesQueue.set(pageStats.pageUrl, pageStats);
	if (processPageRecordQueueTimer === null) {
            processPageRecordQueueTimer =
		vAPI.setTimeout(processPageRecordQueue, 1000);
	}
    };

    let cookieLogEntryBuilder = [
	'',
	'{',
	'',
	'-cookie:',
	'',
	'}'
    ];

    let recordPageCookie = function (pageStore, key) {
	if (vAPI.isBehindTheSceneTabId(pageStore.tabId)) {
	    return;
	}

	let entry = CookieCache.get(key);
	let pageHostname = pageStore.pageHostname;
	let block = ηm.mustBlock(pageHostname, entry.hostname, 'cookie');

	cookieLogEntryBuilder[0] = CookieUtils.urlFromEntry(entry);
	cookieLogEntryBuilder[2] = entry.session ? 'session' : 'persistent';
	cookieLogEntryBuilder[4] = encodeURIComponent(entry.name);

	let cookieURL = cookieLogEntryBuilder.join('');

	// rhill 2013-11-20:
	// https://github.com/gorhill/httpswitchboard/issues/60
	// Need to URL-encode cookie name
	pageStore.recordRequest('cookie', cookieURL, block);
	ηm.logger.writeOne(pageStore.tabId, 'net',
			   pageHostname, cookieURL, 'cookie', block);

	entry.usedOn.add(pageHostname);

	// rhill 2013-11-21:
	// https://github.com/gorhill/httpswitchboard/issues/65
	// Leave alone cookies from behind-the-scene requests if
	// behind-the-scene processing is disabled.
	if (!block) {
            return;
	}
	if (!ηm.userSettings.deleteCookies) {
            return;
	}
	removeCookieAsync(key);
    };

    // Look for cookies to potentially remove for a specific web page

    let removePageCookiesAsync = function (pageStats) {
	// Hold onto pageStats objects so that it doesn't go away
	// before we handle the job.
	// rhill 2013-10-19: pageStats could be nil, for example, this can
	// happens if a file:// ... makes an xmlHttpRequest
	if (!pageStats) {
            return;
	}
	removePageCookiesQueue.set(pageStats.pageUrl, pageStats);
	if (processPageRemoveQueueTimer === null) {
            processPageRemoveQueueTimer =
		vAPI.setTimeout(processPageRemoveQueue, 15 * 1000);
	}
    };

    // Candidate for removal

    let removeCookieAsync = function (key) {
	removeCookieQueue.add(key);
    };

    let chromeCookieRemove = function (entry, name) {
	let url = CookieUtils.urlFromEntry(entry);
	if (url === '') {
            return;
	}
	let sessionKey = CookieUtils.keyFromURL(UriTools.set(url),
						'session', name);
	let persistKey = CookieUtils.keyFromURL(UriTools.set(url),
						'persistent', name);

	let callback = function(details) {
            let success = !!details;
            let template = success ?
		i18nCookieDeleteSuccess :
		i18nCookieDeleteFailure;

            if (CookieCache.remove(sessionKey)) {
		if (success) {
                    ηm.cookieRemovedCounter += 1;
		}
		ηm.logger.writeOne('', 'info', 'cookie',
				   template.replace('{{value}}',
						    sessionKey));
            }
            if (CookieCache.remove(persistKey)) {
		if (success) {
                    ηm.cookieRemovedCounter += 1;
		}
		ηm.logger.writeOne('', 'info', 'cookie',
				   template.replace('{{value}}',
						    persistKey));
            }
	};

	vAPI.cookies.remove({
	    url: url, name: name
	}, callback);
    };

    let i18nCookieDeleteSuccess = vAPI.i18n('loggerEntryCookieDeleted');
    let i18nCookieDeleteFailure = vAPI.i18n('loggerEntryDeleteCookieError');

    let processPageRecordQueue = function () {
	processPageRecordQueueTimer = null;

	for (let pageStore of recordPageCookiesQueue.values()) {
            findAndRecordPageCookies(pageStore);
	}
	recordPageCookiesQueue.clear();
    };

    let processPageRemoveQueue = function () {
	processPageRemoveQueueTimer = null;

	for (let pageStore of removePageCookiesQueue.values()) {
            findAndRemovePageCookies(pageStore);
	}
	removePageCookiesQueue.clear();
    };

    // Effectively remove cookies.

    let processRemoveQueue = function () {
	let userSettings = ηm.userSettings;
	let deleteCookies = userSettings.deleteCookies;

	// Session cookies which timestamp is *after* tstampObsolete will
	// be left untouched
	// https://github.com/gorhill/httpswitchboard/issues/257
	let dusc = userSettings.deleteUnusedSessionCookies;
	let dusca = userSettings.deleteUnusedSessionCookiesAfter;
	let tstampObsolete = dusc ?
	    Date.now() - dusca * 60 * 1000 :
            0;

	let srcHostnames;
	let entry;

	for (let key of removeCookieQueue) {
            // rhill 2014-05-12: Apparently this can happen. I have to
            // investigate how (A session cookie has same name as a
            // persistent cookie?)
            entry = CookieCache.get(key);
            if (entry === undefined) {
		continue;
	    }

            // Delete obsolete session cookies: enabled.
            if (tstampObsolete !== 0 && entry.session) {
		if (entry.tstamp < tstampObsolete) {
                    chromeCookieRemove(entry, entry.name);
                    continue;
		}
            }

            // Delete all blocked cookies: disabled.
            if (deleteCookies === false) {
		continue;
            }

            // Query scopes only if we are going to use them
            if (srcHostnames === undefined) {
		srcHostnames = ηm.tMatrix.extractAllSourceHostnames();
            }

            // Ensure cookie is not allowed on ALL current web pages: It can
            // happen that a cookie is blacklisted on one web page while
            // being whitelisted on another (because of per-page permissions).
            if (canRemoveCookie(key, srcHostnames)) {
		chromeCookieRemove(entry, entry.name);
            }
	}

	removeCookieQueue.clear();

	vAPI.setTimeout(processRemoveQueue, processRemoveQueuePeriod);
    };

    // Once in a while, we go ahead and clean everything that might have been
    // left behind.

    // Remove only some of the cookies which are candidate for removal: who knows,
    // maybe a user has 1000s of cookies sitting in his browser...

    let processClean = function () {
	let us = ηm.userSettings;

	if (us.deleteCookies || us.deleteUnusedSessionCookies) {
            let keys = Array.from(CookieCache.keys());
	    let len = keys.length;
	    let step, offset, n;

            if (len > 25) {
		step = len / 25;
		offset = Math.floor(Math.random() * len);
		n = 25;
            } else {
		step = 1;
		offset = 0;
		n = len;
            }

            let i = offset;
            while (n--) {
		removeCookieAsync(keys[Math.floor(i % len)]);
		i += step;
            }
	}

	vAPI.setTimeout(processClean, processCleanPeriod);
    };

    let findAndRecordPageCookies = function (pageStore) {
	for (let key of CookieCache.keys()) {
            if (CookieUtils.matchDomains(key, pageStore.allHostnamesString)) {
		recordPageCookie(pageStore, key);
            }
	}
    };

    let findAndRemovePageCookies = function (pageStore) {
	for (let key of CookieCache.keys()) {
            if (CookieUtils.matchDomains(key, pageStore.allHostnamesString)) {
		removeCookieAsync(key);
            }
	}
    };

    let canRemoveCookie = function (key, srcHostnames) {
	let entry = CookieCache.get(key);
	if (entry === undefined) {
	    return false;
	}

	let cookieHostname = entry.hostname;
	let srcHostname;

	for (srcHostname of entry.usedOn) {
            if (ηm.mustAllow(srcHostname, cookieHostname, 'cookie')) {
		return false;
            }
	}

	// Maybe there is a scope in which the cookie is 1st-party-allowed.
	// For example, if I am logged in into `github.com`, I do not want to be
	// logged out just because I did not yet open a `github.com` page after
	// re-starting the browser.
	srcHostname = cookieHostname;

	let pos;

	for (;;) {
            if (srcHostnames.has(srcHostname)) {
		if (ηm.mustAllow(srcHostname, cookieHostname, 'cookie')) {
                    return false;
		}
            }
            if (srcHostname === entry.domain) {
		break;
            }
            pos = srcHostname.indexOf('.');
            if (pos === -1) {
		break;
            }
            srcHostname = srcHostname.slice(pos + 1);
	}
	return true;
    };

    // Listen to any change in cookieland, we will update page stats accordingly.

    vAPI.cookies.onChanged = function (cookie) {
	// rhill 2013-12-11: If cookie value didn't change, no need to record.
	// https://github.com/gorhill/httpswitchboard/issues/79
	let key = CookieUtils.keyFromCookie(cookie);
	let entry = CookieCache.get(key);

	if (entry === undefined) {
            entry = CookieCache.add(cookie);
	} else {
            entry.tstamp = Date.now();
            if (cookie.value === entry.value) {
		return;
	    }
            entry.value = cookie.value;
	}

	// Go through all pages and update if needed, as one cookie can be used
	// by many web pages, so they need to be recorded for all these pages.
	let pageStores = ηm.pageStores;
	let pageStore;
	for (let tabId in pageStores) {
            if (pageStores.hasOwnProperty(tabId) === false) {
		continue;
            }
            pageStore = pageStores[tabId];
            if (!CookieUtils.matchDomains(key, pageStore.allHostnamesString)) {
		continue;
            }
            recordPageCookie(pageStore, key);
	}
    };

    // Listen to any change in cookieland, we will update page stats accordingly.

    vAPI.cookies.onRemoved = function (cookie) {
	let key = CookieUtils.keyFromCookie(cookie);
	if (CookieCache.remove(key)) {
            ηm.logger.writeOne('', 'info', 'cookie',
			       i18nCookieDeleteSuccess.replace('{{value}}',
							       key));
	}
    };

    // Listen to any change in cookieland, we will update page stats accordingly.

    vAPI.cookies.onAllRemoved = function () {
	for (let key of CookieCache.keys()) {
            if (CookieCache.remove(key)) {
		ηm.logger.writeOne('', 'info', 'cookie',
				   i18nCookieDeleteSuccess.replace('{{value}}',
								   key));
            }
	}
    };

    vAPI.cookies.getAll(CookieCache.addVector);
    vAPI.cookies.start();

    vAPI.setTimeout(processRemoveQueue, processRemoveQueuePeriod);
    vAPI.setTimeout(processClean, processCleanPeriod);

    // Expose only what is necessary

    return {
	recordPageCookies: recordPageCookiesAsync,
	removePageCookies: removePageCookiesAsync
    };
})();