WireGuard rework for Linux

client/platforms/linux/daemon/dnsutilslinux.cpp

@@ -0,0 +1,212 @@
+/* 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/. */
+
+#include "dnsutilslinux.h"
+
+#include <net/if.h>
+
+#include <QDBusVariant>
+#include <QtDBus/QtDBus>
+
+#include "leakdetector.h"
+#include "logger.h"
+
+constexpr const char* DBUS_RESOLVE_SERVICE = "org.freedesktop.resolve1";
+constexpr const char* DBUS_RESOLVE_PATH = "/org/freedesktop/resolve1";
+constexpr const char* DBUS_RESOLVE_MANAGER = "org.freedesktop.resolve1.Manager";
+constexpr const char* DBUS_PROPERTY_INTERFACE =
+    "org.freedesktop.DBus.Properties";
+
+namespace {
+Logger logger("DnsUtilsLinux");
+}
+
+DnsUtilsLinux::DnsUtilsLinux(QObject* parent) : DnsUtils(parent) {
+  MZ_COUNT_CTOR(DnsUtilsLinux);
+  logger.debug() << "DnsUtilsLinux created.";
+
+  QDBusConnection conn = QDBusConnection::systemBus();
+  m_resolver = new QDBusInterface(DBUS_RESOLVE_SERVICE, DBUS_RESOLVE_PATH,
+                                  DBUS_RESOLVE_MANAGER, conn, this);
+}
+
+DnsUtilsLinux::~DnsUtilsLinux() {
+  MZ_COUNT_DTOR(DnsUtilsLinux);
+
+  for (auto iterator = m_linkDomains.constBegin();
+       iterator != m_linkDomains.constEnd(); ++iterator) {
+    QList<QVariant> argumentList;
+    argumentList << QVariant::fromValue(iterator.key());
+    argumentList << QVariant::fromValue(iterator.value());
+    m_resolver->asyncCallWithArgumentList(QStringLiteral("SetLinkDomains"),
+                                          argumentList);
+  }
+
+  if (m_ifindex > 0) {
+    m_resolver->asyncCall(QStringLiteral("RevertLink"), m_ifindex);
+  }
+
+  logger.debug() << "DnsUtilsLinux destroyed.";
+}
+
+bool DnsUtilsLinux::updateResolvers(const QString& ifname,
+                                    const QList<QHostAddress>& resolvers) {
+  m_ifindex = if_nametoindex(qPrintable(ifname));
+  if (m_ifindex <= 0) {
+    logger.error() << "Unable to resolve ifindex for" << ifname;
+    return false;
+  }
+
+  setLinkDNS(m_ifindex, resolvers);
+  setLinkDefaultRoute(m_ifindex, true);
+  updateLinkDomains();
+  return true;
+}
+
+bool DnsUtilsLinux::restoreResolvers() {
+  for (auto iterator = m_linkDomains.constBegin();
+       iterator != m_linkDomains.constEnd(); ++iterator) {
+    setLinkDomains(iterator.key(), iterator.value());
+  }
+  m_linkDomains.clear();
+
+  /* Revert the VPN interface's DNS configuration */
+  if (m_ifindex > 0) {
+    QList<QVariant> argumentList = {QVariant::fromValue(m_ifindex)};
+    QDBusPendingReply<> reply = m_resolver->asyncCallWithArgumentList(
+        QStringLiteral("RevertLink"), argumentList);
+
+    QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher(reply, this);
+    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this,
+                     SLOT(dnsCallCompleted(QDBusPendingCallWatcher*)));
+
+    m_ifindex = 0;
+  }
+
+  return true;
+}
+
+void DnsUtilsLinux::dnsCallCompleted(QDBusPendingCallWatcher* call) {
+  QDBusPendingReply<> reply = *call;
+  if (reply.isError()) {
+    logger.error() << "Error received from the DBus service";
+  }
+  delete call;
+}
+
+void DnsUtilsLinux::setLinkDNS(int ifindex,
+                               const QList<QHostAddress>& resolvers) {
+  QList<DnsResolver> resolverList;
+  char ifnamebuf[IF_NAMESIZE];
+  const char* ifname = if_indextoname(ifindex, ifnamebuf);
+  for (const auto& ip : resolvers) {
+    resolverList.append(ip);
+    if (ifname) {
+      logger.debug() << "Adding DNS resolver" << ip.toString() << "via"
+                     << ifname;
+    }
+  }
+
+  QList<QVariant> argumentList;
+  argumentList << QVariant::fromValue(ifindex);
+  argumentList << QVariant::fromValue(resolverList);
+  QDBusPendingReply<> reply = m_resolver->asyncCallWithArgumentList(
+      QStringLiteral("SetLinkDNS"), argumentList);
+
+  QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher(reply, this);
+  QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this,
+                   SLOT(dnsCallCompleted(QDBusPendingCallWatcher*)));
+}
+
+void DnsUtilsLinux::setLinkDomains(int ifindex,
+                                   const QList<DnsLinkDomain>& domains) {
+  char ifnamebuf[IF_NAMESIZE];
+  const char* ifname = if_indextoname(ifindex, ifnamebuf);
+  if (ifname) {
+    for (const auto& d : domains) {
+      // The DNS search domains often winds up revealing user's ISP which
+      // can correlate back to their location.
+      logger.debug() << "Setting DNS domain:" << logger.sensitive(d.domain)
+                     << "via" << ifname << (d.search ? "search" : "");
+    }
+  }
+
+  QList<QVariant> argumentList;
+  argumentList << QVariant::fromValue(ifindex);
+  argumentList << QVariant::fromValue(domains);
+  QDBusPendingReply<> reply = m_resolver->asyncCallWithArgumentList(
+      QStringLiteral("SetLinkDomains"), argumentList);
+
+  QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher(reply, this);
+  QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this,
+                   SLOT(dnsCallCompleted(QDBusPendingCallWatcher*)));
+}
+
+void DnsUtilsLinux::setLinkDefaultRoute(int ifindex, bool enable) {
+  QList<QVariant> argumentList;
+  argumentList << QVariant::fromValue(ifindex);
+  argumentList << QVariant::fromValue(enable);
+  QDBusPendingReply<> reply = m_resolver->asyncCallWithArgumentList(
+      QStringLiteral("SetLinkDefaultRoute"), argumentList);
+
+  QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher(reply, this);
+  QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this,
+                   SLOT(dnsCallCompleted(QDBusPendingCallWatcher*)));
+}
+
+void DnsUtilsLinux::updateLinkDomains() {
+  /* Get the list of search domains, and remove any others that might conspire
+   * to satisfy DNS resolution. Unfortunately, this is a pain because Qt doesn't
+   * seem to be able to demarshall complex property types.
+   */
+  QDBusMessage message = QDBusMessage::createMethodCall(
+      DBUS_RESOLVE_SERVICE, DBUS_RESOLVE_PATH, DBUS_PROPERTY_INTERFACE, "Get");
+  message << QString(DBUS_RESOLVE_MANAGER);
+  message << QString("Domains");
+  QDBusPendingReply<QVariant> reply =
+      m_resolver->connection().asyncCall(message);
+
+  QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher(reply, this);
+  QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this,
+                   SLOT(dnsDomainsReceived(QDBusPendingCallWatcher*)));
+}
+
+void DnsUtilsLinux::dnsDomainsReceived(QDBusPendingCallWatcher* call) {
+  QDBusPendingReply<QVariant> reply = *call;
+  if (reply.isError()) {
+    logger.error() << "Error retrieving the DNS  domains from the DBus service";
+    delete call;
+    return;
+  }
+
+  /* Update the state of the DNS domains */
+  m_linkDomains.clear();
+  QDBusArgument args = qvariant_cast<QDBusArgument>(reply.value());
+  QList<DnsDomain> list = qdbus_cast<QList<DnsDomain>>(args);
+  for (const auto& d : list) {
+    if (d.ifindex == 0) {
+      continue;
+    }
+    m_linkDomains[d.ifindex].append(DnsLinkDomain(d.domain, d.search));
+  }
+
+  /* Drop any competing root search domains. */
+  DnsLinkDomain root = DnsLinkDomain(".", true);
+  for (auto iterator = m_linkDomains.constBegin();
+       iterator != m_linkDomains.constEnd(); ++iterator) {
+    if (!iterator.value().contains(root)) {
+      continue;
+    }
+    QList<DnsLinkDomain> newlist = iterator.value();
+    newlist.removeAll(root);
+    setLinkDomains(iterator.key(), newlist);
+  }
+
+  /* Add a root search domain for the new interface. */
+  QList<DnsLinkDomain> newlist = {root};
+  setLinkDomains(m_ifindex, newlist);
+  delete call;
+}
+
+static DnsMetatypeRegistrationProxy s_dnsMetatypeProxy;