src/webui/webapplication.cpp

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2014, 2022-2023  Vladimir Golovnev <glassez@yandex.ru>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  *
  19  * In addition, as a special exception, the copyright holders give permission to
  20  * link this program with the OpenSSL project's "OpenSSL" library (or with
  21  * modified versions of it that use the same license as the "OpenSSL" library),
  22  * and distribute the linked executables. You must obey the GNU General Public
  23  * License in all respects for all of the code used other than "OpenSSL".  If you
  24  * modify file(s), you may extend this exception to your version of the file(s),
  25  * but you are not obligated to do so. If you do not wish to do so, delete this
  26  * exception statement from your version.
  27  */
  28
  29 #include "webapplication.h"
  30
  31 #include <algorithm>
  32 #include <chrono>
  33
  34 #include <QDateTime>
  35 #include <QDebug>
  36 #include <QDir>
  37 #include <QFileInfo>
  38 #include <QJsonDocument>
  39 #include <QMetaObject>
  40 #include <QMimeDatabase>
  41 #include <QMimeType>
  42 #include <QNetworkCookie>
  43 #include <QRegularExpression>
  44 #include <QThread>
  45 #include <QTimer>
  46 #include <QUrl>
  47
  48 #include "base/algorithm.h"
  49 #include "base/http/httperror.h"
  50 #include "base/logger.h"
  51 #include "base/preferences.h"
  52 #include "base/types.h"
  53 #include "base/utils/fs.h"
  54 #include "base/utils/io.h"
  55 #include "base/utils/misc.h"
  56 #include "base/utils/random.h"
  57 #include "base/utils/string.h"
  58 #include "api/apierror.h"
  59 #include "api/appcontroller.h"
  60 #include "api/authcontroller.h"
  61 #include "api/logcontroller.h"
  62 #include "api/rsscontroller.h"
  63 #include "api/searchcontroller.h"
  64 #include "api/synccontroller.h"
  65 #include "api/torrentscontroller.h"
  66 #include "api/transfercontroller.h"
  67 #include "freediskspacechecker.h"
  68
  69 const int MAX_ALLOWED_FILESIZE = 10 * 1024 * 1024;
  70 const QString DEFAULT_SESSION_COOKIE_NAME = u"SID"_s;
  71
  72 const QString WWW_FOLDER = u":/www"_s;
  73 const QString PUBLIC_FOLDER = u"/public"_s;
  74 const QString PRIVATE_FOLDER = u"/private"_s;
  75
  76 using namespace std::chrono_literals;
  77
  78 const std::chrono::seconds FREEDISKSPACE_CHECK_TIMEOUT = 30s;
  79
  80 namespace
  81 {
  82     QStringMap parseCookie(const QStringView cookieStr)
  83     {
  84         // [rfc6265] 4.2.1. Syntax
  85         QStringMap ret;
  86         const QList<QStringView> cookies = cookieStr.split(u';', Qt::SkipEmptyParts);
  87
  88         for (const auto &cookie : cookies)
  89         {
  90             const int idx = cookie.indexOf(u'=');
  91             if (idx < 0)
  92                 continue;
  93
  94             const QString name = cookie.left(idx).trimmed().toString();
  95             const QString value = Utils::String::unquote(cookie.mid(idx + 1).trimmed()).toString();
  96             ret.insert(name, value);
  97         }
  98         return ret;
  99     }
 100
 101     QUrl urlFromHostHeader(const QString &hostHeader)
 102     {
 103         if (!hostHeader.contains(u"://"))
 104             return {u"http://"_s + hostHeader};
 105         return hostHeader;
 106     }
 107
 108     QString getCachingInterval(QString contentType)
 109     {
 110         contentType = contentType.toLower();
 111
 112         if (contentType.startsWith(u"image/"))
 113             return u"private, max-age=604800"_s;  // 1 week
 114
 115         if ((contentType == Http::CONTENT_TYPE_CSS)
 116             || (contentType == Http::CONTENT_TYPE_JS))
 117             {
 118             // short interval in case of program update
 119             return u"private, max-age=43200"_s;  // 12 hrs
 120         }
 121
 122         return u"no-store"_s;
 123     }
 124
 125     QString createLanguagesOptionsHtml()
 126     {
 127         // List language files
 128         const QDir langDir {u":/www/translations"_s};
 129         const QStringList langFiles = langDir.entryList(QStringList(u"webui_*.qm"_s), QDir::Files);
 130         QStringList languages;
 131         for (const QString &langFile : langFiles)
 132         {
 133             const QString localeStr = langFile.section(u"_"_s, 1, -1).section(u"."_s, 0, 0); // remove "webui_" and ".qm"
 134             languages << u"<option value=\"%1\">%2</option>"_s.arg(localeStr, Utils::Misc::languageToLocalizedString(localeStr));
 135             qDebug() << "Supported locale:" << localeStr;
 136         }
 137
 138         return languages.join(u'\n');
 139     }
 140
 141     bool isValidCookieName(const QString &cookieName)
 142     {
 143         if (cookieName.isEmpty() || (cookieName.size() > 128))
 144             return false;
 145
 146         const QRegularExpression invalidNameRegex {u"[^a-zA-Z0-9_\\-]"_s};
 147         if (invalidNameRegex.match(cookieName).hasMatch())
 148             return false;
 149
 150         return true;
 151     }
 152 }
 153
 154 WebApplication::WebApplication(IApplication *app, QObject *parent)
 155     : QObject(parent)
 156     , ApplicationComponent(app)
 157     , m_cacheID {QString::number(Utils::Random::rand(), 36)}
 158     , m_authController {new AuthController(this, app, this)}
 159     , m_workerThread {new QThread}
 160     , m_freeDiskSpaceChecker {new FreeDiskSpaceChecker}
 161     , m_freeDiskSpaceCheckingTimer {new QTimer(this)}
 162 {
 163     declarePublicAPI(u"auth/login"_s);
 164
 165     configure();
 166     connect(Preferences::instance(), &Preferences::changed, this, &WebApplication::configure);
 167
 168     m_sessionCookieName = Preferences::instance()->getWebAPISessionCookieName();
 169     if (!isValidCookieName(m_sessionCookieName))
 170     {
 171         if (!m_sessionCookieName.isEmpty())
 172         {
 173             LogMsg(tr("Unacceptable session cookie name is specified: '%1'. Default one is used.")
 174                    .arg(m_sessionCookieName), Log::WARNING);
 175         }
 176         m_sessionCookieName = DEFAULT_SESSION_COOKIE_NAME;
 177     }
 178
 179     m_freeDiskSpaceChecker->moveToThread(m_workerThread.get());
 180     connect(m_workerThread.get(), &QThread::finished, m_freeDiskSpaceChecker, &QObject::deleteLater);
 181     m_workerThread->start();
 182
 183     m_freeDiskSpaceCheckingTimer->setInterval(FREEDISKSPACE_CHECK_TIMEOUT);
 184     m_freeDiskSpaceCheckingTimer->setSingleShot(true);
 185     connect(m_freeDiskSpaceCheckingTimer, &QTimer::timeout, m_freeDiskSpaceChecker, &FreeDiskSpaceChecker::check);
 186     connect(m_freeDiskSpaceChecker, &FreeDiskSpaceChecker::checked, m_freeDiskSpaceCheckingTimer, qOverload<>(&QTimer::start));
 187     QMetaObject::invokeMethod(m_freeDiskSpaceChecker, &FreeDiskSpaceChecker::check);
 188 }
 189
 190 WebApplication::~WebApplication()
 191 {
 192     // cleanup sessions data
 193     qDeleteAll(m_sessions);
 194 }
 195
 196 void WebApplication::sendWebUIFile()
 197 {
 198     if (request().path.contains(u'\\'))
 199         throw BadRequestHTTPError();
 200
 201     if (const QList<QStringView> pathItems = QStringView(request().path).split(u'/', Qt::SkipEmptyParts)
 202             ; pathItems.contains(u".") || pathItems.contains(u".."))
 203     {
 204         throw BadRequestHTTPError();
 205     }
 206
 207     const QString path = (request().path != u"/")
 208         ? request().path
 209         : u"/index.html"_s;
 210
 211     Path localPath = m_rootFolder
 212                 / Path(session() ? PRIVATE_FOLDER : PUBLIC_FOLDER)
 213                 / Path(path);
 214     if (!localPath.exists() && session())
 215     {
 216         // try to send public file if there is no private one
 217         localPath = m_rootFolder / Path(PUBLIC_FOLDER) / Path(path);
 218     }
 219
 220     if (m_isAltUIUsed)
 221     {
 222         if (!Utils::Fs::isRegularFile(localPath))
 223             throw InternalServerErrorHTTPError(tr("Unacceptable file type, only regular file is allowed."));
 224
 225         const QString rootFolder = m_rootFolder.data();
 226
 227         QFileInfo fileInfo {localPath.parentPath().data()};
 228         while (fileInfo.path() != rootFolder)
 229         {
 230             if (fileInfo.isSymLink())
 231                 throw InternalServerErrorHTTPError(tr("Symlinks inside alternative UI folder are forbidden."));
 232
 233             fileInfo.setFile(fileInfo.path());
 234         }
 235     }
 236
 237     sendFile(localPath);
 238 }
 239
 240 void WebApplication::translateDocument(QString &data) const
 241 {
 242     const QRegularExpression regex(u"QBT_TR\\((([^\\)]|\\)(?!QBT_TR))+)\\)QBT_TR\\[CONTEXT=([a-zA-Z_][a-zA-Z0-9_]*)\\]"_s);
 243
 244     int i = 0;
 245     bool found = true;
 246     while (i < data.size() && found)
 247     {
 248         QRegularExpressionMatch regexMatch;
 249         i = data.indexOf(regex, i, &regexMatch);
 250         if (i >= 0)
 251         {
 252             const QString sourceText = regexMatch.captured(1);
 253             const QString context = regexMatch.captured(3);
 254
 255             const QString loadedText = m_translationFileLoaded
 256                 ? m_translator.translate(context.toUtf8().constData(), sourceText.toUtf8().constData())
 257                 : QString();
 258             // `loadedText` is empty when translation is not provided
 259             // it should fallback to `sourceText`
 260             QString translation = loadedText.isEmpty() ? sourceText : loadedText;
 261
 262             // Use HTML code for quotes to prevent issues with JS
 263             translation.replace(u'\'', u"&#39;"_s);
 264             translation.replace(u'\"', u"&#34;"_s);
 265
 266             data.replace(i, regexMatch.capturedLength(), translation);
 267             i += translation.length();
 268         }
 269         else
 270         {
 271             found = false; // no more translatable strings
 272         }
 273
 274         data.replace(u"${LANG}"_s, m_currentLocale.left(2));
 275         data.replace(u"${CACHEID}"_s, m_cacheID);
 276     }
 277 }
 278
 279 WebSession *WebApplication::session()
 280 {
 281     return m_currentSession;
 282 }
 283
 284 const Http::Request &WebApplication::request() const
 285 {
 286     return m_request;
 287 }
 288
 289 const Http::Environment &WebApplication::env() const
 290 {
 291     return m_env;
 292 }
 293
 294 void WebApplication::setUsername(const QString &username)
 295 {
 296     m_authController->setUsername(username);
 297 }
 298
 299 void WebApplication::setPasswordHash(const QByteArray &passwordHash)
 300 {
 301     m_authController->setPasswordHash(passwordHash);
 302 }
 303
 304 void WebApplication::doProcessRequest()
 305 {
 306     const QRegularExpressionMatch match = m_apiPathPattern.match(request().path);
 307     if (!match.hasMatch())
 308     {
 309         sendWebUIFile();
 310         return;
 311     }
 312
 313     const QString action = match.captured(u"action"_s);
 314     const QString scope = match.captured(u"scope"_s);
 315
 316     // Check public/private scope
 317     if (!session() && !isPublicAPI(scope, action))
 318         throw ForbiddenHTTPError();
 319
 320     // Find matching API
 321     APIController *controller = nullptr;
 322     if (session())
 323         controller = session()->getAPIController(scope);
 324     if (!controller)
 325     {
 326         if (scope == u"auth")
 327             controller = m_authController;
 328         else
 329             throw NotFoundHTTPError();
 330     }
 331
 332     // Filter HTTP methods
 333     const auto allowedMethodIter = m_allowedMethod.find({scope, action});
 334     if (allowedMethodIter == m_allowedMethod.end())
 335     {
 336         // by default allow both GET, POST methods
 337         if ((m_request.method != Http::METHOD_GET) && (m_request.method != Http::METHOD_POST))
 338             throw MethodNotAllowedHTTPError();
 339     }
 340     else
 341     {
 342         if (*allowedMethodIter != m_request.method)
 343             throw MethodNotAllowedHTTPError();
 344     }
 345
 346     DataMap data;
 347     for (const Http::UploadedFile &torrent : request().files)
 348         data[torrent.filename] = torrent.data;
 349
 350     try
 351     {
 352         const QVariant result = controller->run(action, m_params, data);
 353         switch (result.userType())
 354         {
 355         case QMetaType::QJsonDocument:
 356             print(result.toJsonDocument().toJson(QJsonDocument::Compact), Http::CONTENT_TYPE_JSON);
 357             break;
 358         case QMetaType::QByteArray:
 359             print(result.toByteArray(), Http::CONTENT_TYPE_TXT);
 360             break;
 361         case QMetaType::QString:
 362         default:
 363             print(result.toString(), Http::CONTENT_TYPE_TXT);
 364             break;
 365         }
 366     }
 367     catch (const APIError &error)
 368     {
 369         // re-throw as HTTPError
 370         switch (error.type())
 371         {
 372         case APIErrorType::AccessDenied:
 373             throw ForbiddenHTTPError(error.message());
 374         case APIErrorType::BadData:
 375             throw UnsupportedMediaTypeHTTPError(error.message());
 376         case APIErrorType::BadParams:
 377             throw BadRequestHTTPError(error.message());
 378         case APIErrorType::Conflict:
 379             throw ConflictHTTPError(error.message());
 380         case APIErrorType::NotFound:
 381             throw NotFoundHTTPError(error.message());
 382         default:
 383             Q_ASSERT(false);
 384         }
 385     }
 386 }
 387
 388 void WebApplication::configure()
 389 {
 390     const auto *pref = Preferences::instance();
 391
 392     const bool isAltUIUsed = pref->isAltWebUIEnabled();
 393     const Path rootFolder = (!isAltUIUsed ? Path(WWW_FOLDER) : pref->getWebUIRootFolder());
 394     if ((isAltUIUsed != m_isAltUIUsed) || (rootFolder != m_rootFolder))
 395     {
 396         m_isAltUIUsed = isAltUIUsed;
 397         m_rootFolder = rootFolder;
 398         m_translatedFiles.clear();
 399         if (!m_isAltUIUsed)
 400             LogMsg(tr("Using built-in WebUI."));
 401         else
 402             LogMsg(tr("Using custom WebUI. Location: \"%1\".").arg(m_rootFolder.toString()));
 403     }
 404
 405     const QString newLocale = pref->getLocale();
 406     if (m_currentLocale != newLocale)
 407     {
 408         m_currentLocale = newLocale;
 409         m_translatedFiles.clear();
 410
 411         m_translationFileLoaded = m_translator.load((m_rootFolder / Path(u"translations/webui_"_s) + newLocale).data());
 412         if (m_translationFileLoaded)
 413         {
 414             LogMsg(tr("WebUI translation for selected locale (%1) has been successfully loaded.")
 415                    .arg(newLocale));
 416         }
 417         else
 418         {
 419             LogMsg(tr("Couldn't load WebUI translation for selected locale (%1).").arg(newLocale), Log::WARNING);
 420         }
 421     }
 422
 423     m_isLocalAuthEnabled = pref->isWebUILocalAuthEnabled();
 424     m_isAuthSubnetWhitelistEnabled = pref->isWebUIAuthSubnetWhitelistEnabled();
 425     m_authSubnetWhitelist = pref->getWebUIAuthSubnetWhitelist();
 426     m_sessionTimeout = pref->getWebUISessionTimeout();
 427
 428     m_domainList = pref->getServerDomains().split(u';', Qt::SkipEmptyParts);
 429     std::for_each(m_domainList.begin(), m_domainList.end(), [](QString &entry) { entry = entry.trimmed(); });
 430
 431     m_isCSRFProtectionEnabled = pref->isWebUICSRFProtectionEnabled();
 432     m_isSecureCookieEnabled = pref->isWebUISecureCookieEnabled();
 433     m_isHostHeaderValidationEnabled = pref->isWebUIHostHeaderValidationEnabled();
 434     m_isHttpsEnabled = pref->isWebUIHttpsEnabled();
 435
 436     m_prebuiltHeaders.clear();
 437     m_prebuiltHeaders.push_back({Http::HEADER_X_XSS_PROTECTION, u"1; mode=block"_s});
 438     m_prebuiltHeaders.push_back({Http::HEADER_X_CONTENT_TYPE_OPTIONS, u"nosniff"_s});
 439
 440     if (!m_isAltUIUsed)
 441     {
 442         m_prebuiltHeaders.push_back({Http::HEADER_CROSS_ORIGIN_OPENER_POLICY, u"same-origin"_s});
 443         m_prebuiltHeaders.push_back({Http::HEADER_REFERRER_POLICY, u"same-origin"_s});
 444     }
 445
 446     const bool isClickjackingProtectionEnabled = pref->isWebUIClickjackingProtectionEnabled();
 447     if (isClickjackingProtectionEnabled)
 448         m_prebuiltHeaders.push_back({Http::HEADER_X_FRAME_OPTIONS, u"SAMEORIGIN"_s});
 449
 450     const QString contentSecurityPolicy =
 451         (m_isAltUIUsed
 452             ? QString()
 453             : u"default-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; script-src 'self' 'unsafe-inline'; object-src 'none'; form-action 'self';"_s)
 454         + (isClickjackingProtectionEnabled ? u" frame-ancestors 'self';"_s : QString())
 455         + (m_isHttpsEnabled ? u" upgrade-insecure-requests;"_s : QString());
 456     if (!contentSecurityPolicy.isEmpty())
 457         m_prebuiltHeaders.push_back({Http::HEADER_CONTENT_SECURITY_POLICY, contentSecurityPolicy});
 458
 459     if (pref->isWebUICustomHTTPHeadersEnabled())
 460     {
 461         const QString customHeaders = pref->getWebUICustomHTTPHeaders();
 462         const QList<QStringView> customHeaderLines = QStringView(customHeaders).trimmed().split(u'\n', Qt::SkipEmptyParts);
 463
 464         for (const QStringView line : customHeaderLines)
 465         {
 466             const int idx = line.indexOf(u':');
 467             if (idx < 0)
 468             {
 469                 // require separator `:` to be present even if `value` field can be empty
 470                 LogMsg(tr("Missing ':' separator in WebUI custom HTTP header: \"%1\"").arg(line.toString()), Log::WARNING);
 471                 continue;
 472             }
 473
 474             const QString header = line.left(idx).trimmed().toString();
 475             const QString value = line.mid(idx + 1).trimmed().toString();
 476             m_prebuiltHeaders.push_back({header, value});
 477         }
 478     }
 479
 480     m_isReverseProxySupportEnabled = pref->isWebUIReverseProxySupportEnabled();
 481     if (m_isReverseProxySupportEnabled)
 482     {
 483         const QStringList proxyList = pref->getWebUITrustedReverseProxiesList().split(u';', Qt::SkipEmptyParts);
 484
 485         m_trustedReverseProxyList.clear();
 486         m_trustedReverseProxyList.reserve(proxyList.size());
 487
 488         for (QString proxy : proxyList)
 489         {
 490             if (!proxy.contains(u'/'))
 491             {
 492                 const QAbstractSocket::NetworkLayerProtocol protocol = QHostAddress(proxy).protocol();
 493                 if (protocol == QAbstractSocket::IPv4Protocol)
 494                 {
 495                     proxy.append(u"/32");
 496                 }
 497                 else if (protocol == QAbstractSocket::IPv6Protocol)
 498                 {
 499                     proxy.append(u"/128");
 500                 }
 501             }
 502
 503             const std::optional<Utils::Net::Subnet> subnet = Utils::Net::parseSubnet(proxy);
 504             if (subnet)
 505                 m_trustedReverseProxyList.push_back(subnet.value());
 506         }
 507
 508         if (m_trustedReverseProxyList.isEmpty())
 509             m_isReverseProxySupportEnabled = false;
 510     }
 511 }
 512
 513 void WebApplication::declarePublicAPI(const QString &apiPath)
 514 {
 515     m_publicAPIs << apiPath;
 516 }
 517
 518 void WebApplication::sendFile(const Path &path)
 519 {
 520     const QDateTime lastModified = Utils::Fs::lastModified(path);
 521
 522     // find translated file in cache
 523     if (!m_isAltUIUsed)
 524     {
 525         if (const auto it = m_translatedFiles.constFind(path);
 526             (it != m_translatedFiles.constEnd()) && (lastModified <= it->lastModified))
 527         {
 528             print(it->data, it->mimeType);
 529             setHeader({Http::HEADER_CACHE_CONTROL, getCachingInterval(it->mimeType)});
 530             return;
 531         }
 532     }
 533
 534     const auto readResult = Utils::IO::readFile(path, MAX_ALLOWED_FILESIZE);
 535     if (!readResult)
 536     {
 537         const QString message = tr("Web server error. %1").arg(readResult.error().message);
 538
 539         switch (readResult.error().status)
 540         {
 541         case Utils::IO::ReadError::NotExist:
 542             qDebug("%s", qUtf8Printable(message));
 543             // don't write log messages here to avoid exhausting the disk space
 544             throw NotFoundHTTPError();
 545
 546         case Utils::IO::ReadError::ExceedSize:
 547             qWarning("%s", qUtf8Printable(message));
 548             LogMsg(message, Log::WARNING);
 549             throw InternalServerErrorHTTPError(readResult.error().message);
 550
 551         case Utils::IO::ReadError::Failed:
 552         case Utils::IO::ReadError::SizeMismatch:
 553             LogMsg(message, Log::WARNING);
 554             throw InternalServerErrorHTTPError(readResult.error().message);
 555         }
 556
 557         throw InternalServerErrorHTTPError(tr("Web server error. Unknown error."));
 558     }
 559
 560     QByteArray data = readResult.value();
 561     const QMimeType mimeType = QMimeDatabase().mimeTypeForFileNameAndData(path.data(), data);
 562     const bool isTranslatable = !m_isAltUIUsed && mimeType.inherits(u"text/plain"_s);
 563
 564     if (isTranslatable)
 565     {
 566         auto dataStr = QString::fromUtf8(data);
 567         // Translate the file
 568         translateDocument(dataStr);
 569
 570         // Add the language options
 571         if (path == (m_rootFolder / Path(PRIVATE_FOLDER) / Path(u"views/preferences.html"_s)))
 572             dataStr.replace(u"${LANGUAGE_OPTIONS}"_s, createLanguagesOptionsHtml());
 573
 574         data = dataStr.toUtf8();
 575         m_translatedFiles[path] = {data, mimeType.name(), lastModified}; // caching translated file
 576     }
 577
 578     print(data, mimeType.name());
 579     setHeader({Http::HEADER_CACHE_CONTROL, getCachingInterval(mimeType.name())});
 580 }
 581
 582 Http::Response WebApplication::processRequest(const Http::Request &request, const Http::Environment &env)
 583 {
 584     m_currentSession = nullptr;
 585     m_request = request;
 586     m_env = env;
 587     m_params.clear();
 588
 589     if (m_request.method == Http::METHOD_GET)
 590     {
 591         for (auto iter = m_request.query.cbegin(); iter != m_request.query.cend(); ++iter)
 592             m_params[iter.key()] = QString::fromUtf8(iter.value());
 593     }
 594     else
 595     {
 596         m_params = m_request.posts;
 597     }
 598
 599     // clear response
 600     clear();
 601
 602     try
 603     {
 604         // block suspicious requests
 605         if ((m_isCSRFProtectionEnabled && isCrossSiteRequest(m_request))
 606             || (m_isHostHeaderValidationEnabled && !validateHostHeader(m_domainList)))
 607         {
 608             throw UnauthorizedHTTPError();
 609         }
 610
 611         // reverse proxy resolve client address
 612         m_clientAddress = resolveClientAddress();
 613
 614         sessionInitialize();
 615         doProcessRequest();
 616     }
 617     catch (const HTTPError &error)
 618     {
 619         status(error.statusCode(), error.statusText());
 620         print((!error.message().isEmpty() ? error.message() : error.statusText()), Http::CONTENT_TYPE_TXT);
 621     }
 622
 623     for (const Http::Header &prebuiltHeader : asConst(m_prebuiltHeaders))
 624         setHeader(prebuiltHeader);
 625
 626     return response();
 627 }
 628
 629 QString WebApplication::clientId() const
 630 {
 631     return m_clientAddress.toString();
 632 }
 633
 634 void WebApplication::sessionInitialize()
 635 {
 636     Q_ASSERT(!m_currentSession);
 637
 638     const QString sessionId {parseCookie(m_request.headers.value(u"cookie"_s)).value(m_sessionCookieName)};
 639
 640     // TODO: Additional session check
 641
 642     if (!sessionId.isEmpty())
 643     {
 644         m_currentSession = m_sessions.value(sessionId);
 645         if (m_currentSession)
 646         {
 647             if (m_currentSession->hasExpired(m_sessionTimeout))
 648             {
 649                 // session is outdated - removing it
 650                 delete m_sessions.take(sessionId);
 651                 m_currentSession = nullptr;
 652             }
 653             else
 654             {
 655                 m_currentSession->updateTimestamp();
 656             }
 657         }
 658         else
 659         {
 660             qDebug() << Q_FUNC_INFO << "session does not exist!";
 661         }
 662     }
 663
 664     if (!m_currentSession && !isAuthNeeded())
 665         sessionStart();
 666 }
 667
 668 QString WebApplication::generateSid() const
 669 {
 670     QString sid;
 671
 672     do
 673     {
 674         const quint32 tmp[] =
 675         {Utils::Random::rand(), Utils::Random::rand(), Utils::Random::rand()
 676                 , Utils::Random::rand(), Utils::Random::rand(), Utils::Random::rand()};
 677         sid = QString::fromLatin1(QByteArray::fromRawData(reinterpret_cast<const char *>(tmp), sizeof(tmp)).toBase64());
 678     }
 679     while (m_sessions.contains(sid));
 680
 681     return sid;
 682 }
 683
 684 bool WebApplication::isAuthNeeded()
 685 {
 686     if (!m_isLocalAuthEnabled && Utils::Net::isLoopbackAddress(m_clientAddress))
 687         return false;
 688     if (m_isAuthSubnetWhitelistEnabled && Utils::Net::isIPInSubnets(m_clientAddress, m_authSubnetWhitelist))
 689         return false;
 690     return true;
 691 }
 692
 693 bool WebApplication::isPublicAPI(const QString &scope, const QString &action) const
 694 {
 695     return m_publicAPIs.contains(u"%1/%2"_s.arg(scope, action));
 696 }
 697
 698 void WebApplication::sessionStart()
 699 {
 700     Q_ASSERT(!m_currentSession);
 701
 702     // remove outdated sessions
 703     Algorithm::removeIf(m_sessions, [this](const QString &, const WebSession *session)
 704     {
 705         if (session->hasExpired(m_sessionTimeout))
 706         {
 707             delete session;
 708             return true;
 709         }
 710
 711         return false;
 712     });
 713
 714     m_currentSession = new WebSession(generateSid(), app());
 715     m_sessions[m_currentSession->id()] = m_currentSession;
 716
 717     m_currentSession->registerAPIController<AppController>(u"app"_s);
 718     m_currentSession->registerAPIController<LogController>(u"log"_s);
 719     m_currentSession->registerAPIController<RSSController>(u"rss"_s);
 720     m_currentSession->registerAPIController<SearchController>(u"search"_s);
 721     m_currentSession->registerAPIController<TorrentsController>(u"torrents"_s);
 722     m_currentSession->registerAPIController<TransferController>(u"transfer"_s);
 723
 724     auto *syncController = m_currentSession->registerAPIController<SyncController>(u"sync"_s);
 725     syncController->updateFreeDiskSpace(m_freeDiskSpaceChecker->lastResult());
 726     connect(m_freeDiskSpaceChecker, &FreeDiskSpaceChecker::checked, syncController, &SyncController::updateFreeDiskSpace);
 727
 728     QNetworkCookie cookie {m_sessionCookieName.toLatin1(), m_currentSession->id().toUtf8()};
 729     cookie.setHttpOnly(true);
 730     cookie.setSecure(m_isSecureCookieEnabled && m_isHttpsEnabled);
 731     cookie.setPath(u"/"_s);
 732     QByteArray cookieRawForm = cookie.toRawForm();
 733     if (m_isCSRFProtectionEnabled)
 734         cookieRawForm.append("; SameSite=Strict");
 735     else if (cookie.isSecure())
 736         cookieRawForm.append("; SameSite=None");
 737     setHeader({Http::HEADER_SET_COOKIE, QString::fromLatin1(cookieRawForm)});
 738 }
 739
 740 void WebApplication::sessionEnd()
 741 {
 742     Q_ASSERT(m_currentSession);
 743
 744     QNetworkCookie cookie {m_sessionCookieName.toLatin1()};
 745     cookie.setPath(u"/"_s);
 746     cookie.setExpirationDate(QDateTime::currentDateTime().addDays(-1));
 747
 748     delete m_sessions.take(m_currentSession->id());
 749     m_currentSession = nullptr;
 750
 751     setHeader({Http::HEADER_SET_COOKIE, QString::fromLatin1(cookie.toRawForm())});
 752 }
 753
 754 bool WebApplication::isCrossSiteRequest(const Http::Request &request) const
 755 {
 756     // https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet#Verifying_Same_Origin_with_Standard_Headers
 757
 758     const auto isSameOrigin = [](const QUrl &left, const QUrl &right) -> bool
 759     {
 760         // [rfc6454] 5. Comparing Origins
 761         return ((left.port() == right.port())
 762                 // && (left.scheme() == right.scheme())  // not present in this context
 763                 && (left.host() == right.host()));
 764     };
 765
 766     const QString targetOrigin = request.headers.value(Http::HEADER_X_FORWARDED_HOST, request.headers.value(Http::HEADER_HOST));
 767     const QString originValue = request.headers.value(Http::HEADER_ORIGIN);
 768     const QString refererValue = request.headers.value(Http::HEADER_REFERER);
 769
 770     if (originValue.isEmpty() && refererValue.isEmpty())
 771     {
 772         // owasp.org recommends to block this request, but doing so will inevitably lead Web API users to spoof headers
 773         // so lets be permissive here
 774         return false;
 775     }
 776
 777     // sent with CORS requests, as well as with POST requests
 778     if (!originValue.isEmpty())
 779     {
 780         const bool isInvalid = !isSameOrigin(urlFromHostHeader(targetOrigin), originValue);
 781         if (isInvalid)
 782         {
 783             LogMsg(tr("WebUI: Origin header & Target origin mismatch! Source IP: '%1'. Origin header: '%2'. Target origin: '%3'")
 784                    .arg(m_env.clientAddress.toString(), originValue, targetOrigin)
 785                    , Log::WARNING);
 786         }
 787         return isInvalid;
 788     }
 789
 790     if (!refererValue.isEmpty())
 791     {
 792         const bool isInvalid = !isSameOrigin(urlFromHostHeader(targetOrigin), refererValue);
 793         if (isInvalid)
 794         {
 795             LogMsg(tr("WebUI: Referer header & Target origin mismatch! Source IP: '%1'. Referer header: '%2'. Target origin: '%3'")
 796                    .arg(m_env.clientAddress.toString(), refererValue, targetOrigin)
 797                    , Log::WARNING);
 798         }
 799         return isInvalid;
 800     }
 801
 802     return true;
 803 }
 804
 805 bool WebApplication::validateHostHeader(const QStringList &domains) const
 806 {
 807     const QUrl hostHeader = urlFromHostHeader(m_request.headers[Http::HEADER_HOST]);
 808     const QString requestHost = hostHeader.host();
 809
 810     // (if present) try matching host header's port with local port
 811     const int requestPort = hostHeader.port();
 812     if ((requestPort != -1) && (m_env.localPort != requestPort))
 813     {
 814         LogMsg(tr("WebUI: Invalid Host header, port mismatch. Request source IP: '%1'. Server port: '%2'. Received Host header: '%3'")
 815                .arg(m_env.clientAddress.toString()).arg(m_env.localPort)
 816                .arg(m_request.headers[Http::HEADER_HOST])
 817                 , Log::WARNING);
 818         return false;
 819     }
 820
 821     // try matching host header with local address
 822     const bool sameAddr = m_env.localAddress.isEqual(QHostAddress(requestHost));
 823
 824     if (sameAddr)
 825         return true;
 826
 827     // try matching host header with domain list
 828     for (const auto &domain : domains)
 829     {
 830         const QRegularExpression domainRegex {Utils::String::wildcardToRegexPattern(domain), QRegularExpression::CaseInsensitiveOption};
 831         if (requestHost.contains(domainRegex))
 832             return true;
 833     }
 834
 835     LogMsg(tr("WebUI: Invalid Host header. Request source IP: '%1'. Received Host header: '%2'")
 836            .arg(m_env.clientAddress.toString(), m_request.headers[Http::HEADER_HOST])
 837             , Log::WARNING);
 838     return false;
 839 }
 840
 841 QHostAddress WebApplication::resolveClientAddress() const
 842 {
 843     if (!m_isReverseProxySupportEnabled)
 844         return m_env.clientAddress;
 845
 846     // Only reverse proxy can overwrite client address
 847     if (!Utils::Net::isIPInSubnets(m_env.clientAddress, m_trustedReverseProxyList))
 848         return m_env.clientAddress;
 849
 850     const QString forwardedFor = m_request.headers.value(Http::HEADER_X_FORWARDED_FOR);
 851
 852     if (!forwardedFor.isEmpty())
 853     {
 854         // client address is the 1st global IP in X-Forwarded-For or, if none available, the 1st IP in the list
 855         const QStringList remoteIpList = forwardedFor.split(u',', Qt::SkipEmptyParts);
 856
 857         if (!remoteIpList.isEmpty())
 858         {
 859             QHostAddress clientAddress;
 860
 861             for (const QString &remoteIp : remoteIpList)
 862             {
 863                 if (clientAddress.setAddress(remoteIp) && clientAddress.isGlobal())
 864                     return clientAddress;
 865             }
 866
 867             if (clientAddress.setAddress(remoteIpList[0]))
 868                 return clientAddress;
 869         }
 870     }
 871
 872     return m_env.clientAddress;
 873 }
 874
 875 // WebSession
 876
 877 WebSession::WebSession(const QString &sid, IApplication *app)
 878     : ApplicationComponent(app)
 879     , m_sid {sid}
 880 {
 881     updateTimestamp();
 882 }
 883
 884 QString WebSession::id() const
 885 {
 886     return m_sid;
 887 }
 888
 889 bool WebSession::hasExpired(const qint64 seconds) const
 890 {
 891     if (seconds <= 0)
 892         return false;
 893     return m_timer.hasExpired(seconds * 1000);
 894 }
 895
 896 void WebSession::updateTimestamp()
 897 {
 898     m_timer.start();
 899 }
 900
 901 APIController *WebSession::getAPIController(const QString &scope) const
 902 {
 903     return m_apiControllers.value(scope);
 904 }