src/base/http/server.cpp

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2014  Vladimir Golovnev <glassez@yandex.ru>
   4  * Copyright (C) 2006  Christophe Dumez <chris@qbittorrent.org>
   5  * Copyright (C) 2006  Ishan Arora <ishan@qbittorrent.org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20  *
  21  * In addition, as a special exception, the copyright holders give permission to
  22  * link this program with the OpenSSL project's "OpenSSL" library (or with
  23  * modified versions of it that use the same license as the "OpenSSL" library),
  24  * and distribute the linked executables. You must obey the GNU General Public
  25  * License in all respects for all of the code used other than "OpenSSL".  If you
  26  * modify file(s), you may extend this exception to your version of the file(s),
  27  * but you are not obligated to do so. If you do not wish to do so, delete this
  28  * exception statement from your version.
  29  */
  30
  31 #include "server.h"
  32
  33 #include <algorithm>
  34 #include <chrono>
  35 #include <memory>
  36 #include <new>
  37
  38 #include <QtLogging>
  39 #include <QNetworkProxy>
  40 #include <QSslCertificate>
  41 #include <QSslCipher>
  42 #include <QSslKey>
  43 #include <QSslSocket>
  44 #include <QStringList>
  45 #include <QTimer>
  46
  47 #include "base/global.h"
  48 #include "base/utils/net.h"
  49 #include "base/utils/sslkey.h"
  50 #include "connection.h"
  51
  52 using namespace std::chrono_literals;
  53
  54 namespace
  55 {
  56     const int KEEP_ALIVE_DURATION = std::chrono::milliseconds(7s).count();
  57     const int CONNECTIONS_LIMIT = 500;
  58     const std::chrono::seconds CONNECTIONS_SCAN_INTERVAL {2};
  59
  60     QList<QSslCipher> safeCipherList()
  61     {
  62         const QStringList badCiphers {u"idea"_s, u"rc4"_s};
  63         // Contains Ciphersuites that use RSA for the Key Exchange but they don't mention it in their name
  64         const QStringList badRSAShorthandSuites {
  65             u"AES256-GCM-SHA384"_s, u"AES128-GCM-SHA256"_s, u"AES256-SHA256"_s,
  66             u"AES128-SHA256"_s, u"AES256-SHA"_s, u"AES128-SHA"_s};
  67         // Contains Ciphersuites that use AES CBC mode but they don't mention it in their name
  68         const QStringList badAESShorthandSuites {
  69             u"ECDHE-ECDSA-AES256-SHA384"_s, u"ECDHE-RSA-AES256-SHA384"_s, u"DHE-RSA-AES256-SHA256"_s,
  70             u"ECDHE-ECDSA-AES128-SHA256"_s, u"ECDHE-RSA-AES128-SHA256"_s, u"DHE-RSA-AES128-SHA256"_s,
  71             u"ECDHE-ECDSA-AES256-SHA"_s, u"ECDHE-RSA-AES256-SHA"_s, u"DHE-RSA-AES256-SHA"_s,
  72             u"ECDHE-ECDSA-AES128-SHA"_s, u"ECDHE-RSA-AES128-SHA"_s, u"DHE-RSA-AES128-SHA"_s};
  73         const QList<QSslCipher> allCiphers {QSslConfiguration::supportedCiphers()};
  74         QList<QSslCipher> safeCiphers;
  75         std::copy_if(allCiphers.cbegin(), allCiphers.cend(), std::back_inserter(safeCiphers),
  76                      [&badCiphers, &badRSAShorthandSuites, &badAESShorthandSuites](const QSslCipher &cipher)
  77         {
  78             const QString name = cipher.name();
  79             if (name.contains(u"-cbc-"_s, Qt::CaseInsensitive) // AES CBC mode is considered vulnerable to BEAST attack
  80                 || name.startsWith(u"adh-"_s, Qt::CaseInsensitive) // Key Exchange: Diffie-Hellman, doesn't support Perfect Forward Secrecy
  81                 || name.startsWith(u"aecdh-"_s, Qt::CaseInsensitive) // Key Exchange: Elliptic Curve Diffie-Hellman, doesn't support Perfect Forward Secrecy
  82                 || name.startsWith(u"psk-"_s, Qt::CaseInsensitive) // Key Exchange: Pre-Shared Key, doesn't support Perfect Forward Secrecy
  83                 || name.startsWith(u"rsa-"_s, Qt::CaseInsensitive) // Key Exchange: Rivest Shamir Adleman (RSA), doesn't support Perfect Forward Secrecy
  84                 || badRSAShorthandSuites.contains(name, Qt::CaseInsensitive)
  85                 || badAESShorthandSuites.contains(name, Qt::CaseInsensitive))
  86             {
  87                 return false;
  88             }
  89
  90             return std::none_of(badCiphers.cbegin(), badCiphers.cend(), [&cipher](const QString &badCipher)
  91             {
  92                 return cipher.name().contains(badCipher, Qt::CaseInsensitive);
  93             });
  94         });
  95         return safeCiphers;
  96     }
  97 }
  98
  99 using namespace Http;
 100
 101 Server::Server(IRequestHandler *requestHandler, QObject *parent)
 102     : QTcpServer(parent)
 103     , m_requestHandler(requestHandler)
 104     , m_sslConfig {QSslConfiguration::defaultConfiguration()}
 105 {
 106     setProxy(QNetworkProxy::NoProxy);
 107
 108     m_sslConfig.setCiphers(safeCipherList());
 109     m_sslConfig.setPeerVerifyMode(QSslSocket::VerifyNone);
 110
 111     auto *dropConnectionTimer = new QTimer(this);
 112     connect(dropConnectionTimer, &QTimer::timeout, this, &Server::dropTimedOutConnection);
 113     dropConnectionTimer->start(CONNECTIONS_SCAN_INTERVAL);
 114 }
 115
 116 void Server::incomingConnection(const qintptr socketDescriptor)
 117 {
 118     std::unique_ptr<QTcpSocket> serverSocket = isHttps() ? std::make_unique<QSslSocket>(this) : std::make_unique<QTcpSocket>(this);
 119     if (!serverSocket->setSocketDescriptor(socketDescriptor))
 120         return;
 121
 122     if (m_connections.size() >= CONNECTIONS_LIMIT)
 123     {
 124         qWarning("Too many connections. Exceeded CONNECTIONS_LIMIT (%d). Connection closed.", CONNECTIONS_LIMIT);
 125         return;
 126     }
 127
 128     try
 129     {
 130         if (isHttps())
 131         {
 132             auto *sslSocket = static_cast<QSslSocket *>(serverSocket.get());
 133             sslSocket->setSslConfiguration(m_sslConfig);
 134             sslSocket->startServerEncryption();
 135         }
 136
 137         auto *connection = new Connection(serverSocket.release(), m_requestHandler, this);
 138         m_connections.insert(connection);
 139         connect(connection, &Connection::closed, this, [this, connection] { removeConnection(connection); });
 140     }
 141     catch (const std::bad_alloc &exception)
 142     {
 143         // drop the connection instead of throwing exception and crash
 144         qWarning("Failed to allocate memory for HTTP connection. Connection closed.");
 145         return;
 146     }
 147 }
 148
 149 void Server::removeConnection(Connection *connection)
 150 {
 151     m_connections.remove(connection);
 152     connection->deleteLater();
 153 }
 154
 155 void Server::dropTimedOutConnection()
 156 {
 157     m_connections.removeIf([](Connection *connection)
 158     {
 159         if (!connection->hasExpired(KEEP_ALIVE_DURATION))
 160             return false;
 161
 162         connection->deleteLater();
 163         return true;
 164     });
 165 }
 166
 167 bool Server::setupHttps(const QByteArray &certificates, const QByteArray &privateKey)
 168 {
 169     const QList<QSslCertificate> certs {Utils::Net::loadSSLCertificate(certificates)};
 170     const QSslKey key {Utils::SSLKey::load(privateKey)};
 171
 172     if (certs.isEmpty() || key.isNull())
 173     {
 174         disableHttps();
 175         return false;
 176     }
 177
 178     m_sslConfig.setLocalCertificateChain(certs);
 179     m_sslConfig.setPrivateKey(key);
 180     m_https = true;
 181     return true;
 182 }
 183
 184 void Server::disableHttps()
 185 {
 186     m_sslConfig.setLocalCertificateChain({});
 187     m_sslConfig.setPrivateKey({});
 188     m_https = false;
 189 }
 190
 191 bool Server::isHttps() const
 192 {
 193     return m_https;
 194 }