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// Copyright 2015 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "apmanager/firewall_manager.h"
#include <base/bind.h>
#include <chromeos/dbus/service_constants.h>
#include <chromeos/errors/error.h>
using std::string;
namespace apmanager {
namespace {
const uint16_t kDhcpServerPort = 67;
const int kInvalidFd = -1;
} // namespace
FirewallManager::FirewallManager()
: lifeline_read_fd_(kInvalidFd),
lifeline_write_fd_(kInvalidFd) {}
FirewallManager::~FirewallManager() {
if (lifeline_read_fd_ != kInvalidFd) {
close(lifeline_read_fd_);
close(lifeline_write_fd_);
}
}
void FirewallManager::Init(const scoped_refptr<dbus::Bus>& bus) {
CHECK(!permission_broker_proxy_) << "Already started";
if (!SetupLifelinePipe()) {
return;
}
permission_broker_proxy_.reset(
new org::chromium::PermissionBrokerProxy(
bus,
permission_broker::kPermissionBrokerServiceName));
// This will connect the name owner changed signal in DBus object proxy,
// The callback will be invoked as soon as service is avalilable. and will
// be cleared after it is invoked. So this will be an one time callback.
permission_broker_proxy_->GetObjectProxy()->WaitForServiceToBeAvailable(
base::Bind(&FirewallManager::OnServiceAvailable, base::Unretained(this)));
// This will continuously monitor the name owner of the service. However,
// it does not connect the name owner changed signal in DBus object proxy
// for some reason. In order to connect the name owner changed signal,
// either WaitForServiceToBeAvaiable or ConnectToSignal need to be invoked.
// Since we're not interested in any signals from the proxy,
// WaitForServiceToBeAvailable is used.
permission_broker_proxy_->GetObjectProxy()->SetNameOwnerChangedCallback(
base::Bind(&FirewallManager::OnServiceNameChanged,
base::Unretained(this)));
}
void FirewallManager::RequestDHCPPortAccess(const std::string& interface) {
CHECK(permission_broker_proxy_) << "Proxy not initialized yet";
if (dhcp_access_interfaces_.find(interface) !=
dhcp_access_interfaces_.end()) {
LOG(ERROR) << "DHCP access already requested for interface: " << interface;
return;
}
RequestUdpPortAccess(interface, kDhcpServerPort);
dhcp_access_interfaces_.insert(interface);
}
void FirewallManager::ReleaseDHCPPortAccess(const std::string& interface) {
CHECK(permission_broker_proxy_) << "Proxy not initialized yet";
if (dhcp_access_interfaces_.find(interface) ==
dhcp_access_interfaces_.end()) {
LOG(ERROR) << "DHCP access has not been requested for interface: "
<< interface;
return;
}
ReleaseUdpPortAccess(interface, kDhcpServerPort);
dhcp_access_interfaces_.erase(interface);
}
bool FirewallManager::SetupLifelinePipe() {
if (lifeline_read_fd_ != kInvalidFd) {
LOG(ERROR) << "Lifeline pipe already created";
return false;
}
// Setup lifeline pipe.
int fds[2];
if (pipe(fds) != 0) {
PLOG(ERROR) << "Failed to create lifeline pipe";
return false;
}
lifeline_read_fd_ = fds[0];
lifeline_write_fd_ = fds[1];
return true;
}
void FirewallManager::OnServiceAvailable(bool service_available) {
LOG(INFO) << "FirewallManager::OnServiceAvailabe " << service_available;
// Nothing to be done if proxy service is not available.
if (!service_available) {
return;
}
RequestAllPortsAccess();
}
void FirewallManager::OnServiceNameChanged(const string& old_owner,
const string& new_owner) {
LOG(INFO) << "FirewallManager::OnServiceNameChanged old " << old_owner
<< " new " << new_owner;
// Nothing to be done if no owner is attached to the proxy service.
if (new_owner.empty()) {
return;
}
RequestAllPortsAccess();
}
void FirewallManager::RequestAllPortsAccess() {
// Request access to DHCP port for all specified interfaces.
for (const auto& dhcp_interface : dhcp_access_interfaces_) {
RequestUdpPortAccess(dhcp_interface, kDhcpServerPort);
}
}
void FirewallManager::RequestUdpPortAccess(const string& interface,
uint16_t port) {
bool allowed = false;
// Pass the read end of the pipe to permission_broker, for it to monitor this
// process.
dbus::FileDescriptor fd(lifeline_read_fd_);
fd.CheckValidity();
chromeos::ErrorPtr error;
if (!permission_broker_proxy_->RequestUdpPortAccess(port,
interface,
fd,
&allowed,
&error)) {
LOG(ERROR) << "Failed to request UDP port access: "
<< error->GetCode() << " " << error->GetMessage();
return;
}
if (!allowed) {
LOG(ERROR) << "Access request for UDP port " << port
<< " on interface " << interface << " is denied";
return;
}
LOG(INFO) << "Access granted for UDP port " << port
<< " on interface " << interface;;
}
void FirewallManager::ReleaseUdpPortAccess(const string& interface,
uint16_t port) {
chromeos::ErrorPtr error;
bool success;
if (!permission_broker_proxy_->ReleaseUdpPort(port,
interface,
&success,
&error)) {
LOG(ERROR) << "Failed to release UDP port access: "
<< error->GetCode() << " " << error->GetMessage();
return;
}
if (!success) {
LOG(ERROR) << "Release request for UDP port " << port
<< " on interface " << interface << " is denied";
return;
}
LOG(INFO) << "Access released for UDP port " << port
<< " on interface " << interface;
}
} // namespace apmanager
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