//
// Copyright (C) 2012 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// The term "L2TP / IPSec" refers to a pair of layered protocols used
// together to establish a tunneled VPN connection. First, an "IPSec"
// link is created, which secures a single IP traffic pair between the
// client and server. For this link to complete, one or two levels of
// authentication are performed. The first, inner mandatory authentication
// ensures the two parties establishing the IPSec link are correct. This
// can use a certificate exchange or a less secure "shared group key"
// (PSK) authentication. An optional outer IPSec authentication can also be
// performed, which is not fully supported by shill's implementation.
// In order to support "tunnel groups" from some vendor VPNs shill supports
// supplying the authentication realm portion during the outer authentication.
// Notably, XAUTH and other forms of user authentication on this outer link
// are not supported.
//
// When IPSec authentication completes, traffic is tunneled through a
// layer 2 tunnel, called "L2TP". Using the secured link, we tunnel a
// PPP link, through which a second layer of authentication is performed,
// using the provided "user" and "password" properties.
#include "shill/vpn/l2tp_ipsec_driver.h"
#include <base/bind.h>
#include <base/files/file_util.h>
#include <base/strings/string_util.h>
#include <base/strings/stringprintf.h>
#if defined(__ANDROID__)
#include <dbus/service_constants.h>
#else
#include <chromeos/dbus/service_constants.h>
#endif // __ANDROID__
#include <vpn-manager/service_error.h>
#include "shill/certificate_file.h"
#include "shill/device_info.h"
#include "shill/error.h"
#include "shill/external_task.h"
#include "shill/ipconfig.h"
#include "shill/logging.h"
#include "shill/manager.h"
#include "shill/ppp_daemon.h"
#include "shill/ppp_device.h"
#include "shill/ppp_device_factory.h"
#include "shill/process_manager.h"
#include "shill/vpn/vpn_service.h"
using base::Bind;
using base::Closure;
using base::FilePath;
using std::map;
using std::string;
using std::vector;
namespace shill {
namespace Logging {
static auto kModuleLogScope = ScopeLogger::kVPN;
static string ObjectID(L2TPIPSecDriver* l) {
return l->GetServiceRpcIdentifier();
}
}
namespace {
const char kL2TPIPSecIPSecTimeoutProperty[] = "L2TPIPsec.IPsecTimeout";
const char kL2TPIPSecLeftProtoPortProperty[] = "L2TPIPsec.LeftProtoPort";
const char kL2TPIPSecLengthBitProperty[] = "L2TPIPsec.LengthBit";
const char kL2TPIPSecPFSProperty[] = "L2TPIPsec.PFS";
const char kL2TPIPSecRefusePapProperty[] = "L2TPIPsec.RefusePap";
const char kL2TPIPSecRekeyProperty[] = "L2TPIPsec.Rekey";
const char kL2TPIPSecRequireAuthProperty[] = "L2TPIPsec.RequireAuth";
const char kL2TPIPSecRequireChapProperty[] = "L2TPIPsec.RequireChap";
const char kL2TPIPSecRightProtoPortProperty[] = "L2TPIPsec.RightProtoPort";
} // namespace
// static
const char L2TPIPSecDriver::kL2TPIPSecVPNPath[] = "/usr/sbin/l2tpipsec_vpn";
// static
const VPNDriver::Property L2TPIPSecDriver::kProperties[] = {
{ kL2tpIpsecAuthenticationType, 0 },
{ kL2tpIpsecCaCertNssProperty, 0 },
{ kL2tpIpsecClientCertIdProperty, 0 },
{ kL2tpIpsecClientCertSlotProperty, 0 },
{ kL2tpIpsecIkeVersion, 0 },
{ kL2tpIpsecPasswordProperty, Property::kCredential | Property::kWriteOnly },
{ kL2tpIpsecPinProperty, Property::kCredential },
{ kL2tpIpsecPskProperty, Property::kCredential | Property::kWriteOnly },
{ kL2tpIpsecUserProperty, 0 },
{ kProviderHostProperty, 0 },
{ kProviderTypeProperty, 0 },
{ kL2tpIpsecCaCertPemProperty, Property::kArray },
{ kL2tpIpsecTunnelGroupProperty, 0 },
{ kL2TPIPSecIPSecTimeoutProperty, 0 },
{ kL2TPIPSecLeftProtoPortProperty, 0 },
{ kL2TPIPSecLengthBitProperty, 0 },
{ kL2TPIPSecPFSProperty, 0 },
{ kL2TPIPSecRefusePapProperty, 0 },
{ kL2TPIPSecRekeyProperty, 0 },
{ kL2TPIPSecRequireAuthProperty, 0 },
{ kL2TPIPSecRequireChapProperty, 0 },
{ kL2TPIPSecRightProtoPortProperty, 0 },
{ kL2tpIpsecXauthUserProperty, Property::kCredential | Property::kWriteOnly },
{ kL2tpIpsecXauthPasswordProperty,
Property::kCredential | Property::kWriteOnly },
{ kL2tpIpsecLcpEchoDisabledProperty, 0 },
};
L2TPIPSecDriver::L2TPIPSecDriver(ControlInterface* control,
EventDispatcher* dispatcher,
Metrics* metrics,
Manager* manager,
DeviceInfo* device_info,
ProcessManager* process_manager)
: VPNDriver(dispatcher, manager, kProperties, arraysize(kProperties)),
control_(control),
metrics_(metrics),
device_info_(device_info),
process_manager_(process_manager),
ppp_device_factory_(PPPDeviceFactory::GetInstance()),
certificate_file_(new CertificateFile()),
weak_ptr_factory_(this) {}
L2TPIPSecDriver::~L2TPIPSecDriver() {
IdleService();
}
std::string L2TPIPSecDriver::GetServiceRpcIdentifier() {
if (service_ == nullptr)
return "(l2tp_ipsec_driver)";
return service_->GetRpcIdentifier();
}
bool L2TPIPSecDriver::ClaimInterface(const string& link_name,
int interface_index) {
// TODO(petkov): crbug.com/212446.
NOTIMPLEMENTED();
return false;
}
void L2TPIPSecDriver::Connect(const VPNServiceRefPtr& service, Error* error) {
StartConnectTimeout(kDefaultConnectTimeoutSeconds);
service_ = service;
service_->SetState(Service::kStateConfiguring);
if (!SpawnL2TPIPSecVPN(error)) {
FailService(Service::kFailureInternal);
}
}
void L2TPIPSecDriver::Disconnect() {
SLOG(this, 2) << __func__;
IdleService();
}
void L2TPIPSecDriver::OnConnectionDisconnected() {
LOG(INFO) << "Underlying connection disconnected.";
IdleService();
}
void L2TPIPSecDriver::OnConnectTimeout() {
VPNDriver::OnConnectTimeout();
FailService(Service::kFailureConnect);
}
string L2TPIPSecDriver::GetProviderType() const {
return kProviderL2tpIpsec;
}
void L2TPIPSecDriver::IdleService() {
Cleanup(Service::kStateIdle, Service::kFailureUnknown);
}
void L2TPIPSecDriver::FailService(Service::ConnectFailure failure) {
Cleanup(Service::kStateFailure, failure);
}
void L2TPIPSecDriver::Cleanup(Service::ConnectState state,
Service::ConnectFailure failure) {
SLOG(this, 2) << __func__ << "("
<< Service::ConnectStateToString(state) << ", "
<< Service::ConnectFailureToString(failure) << ")";
StopConnectTimeout();
DeleteTemporaryFiles();
external_task_.reset();
if (device_) {
device_->DropConnection();
device_->SetEnabled(false);
device_ = nullptr;
}
if (service_) {
if (state == Service::kStateFailure) {
service_->SetFailure(failure);
} else {
service_->SetState(state);
}
service_ = nullptr;
}
}
void L2TPIPSecDriver::DeleteTemporaryFile(base::FilePath* temporary_file) {
if (!temporary_file->empty()) {
base::DeleteFile(*temporary_file, false);
temporary_file->clear();
}
}
void L2TPIPSecDriver::DeleteTemporaryFiles() {
DeleteTemporaryFile(&psk_file_);
DeleteTemporaryFile(&xauth_credentials_file_);
}
bool L2TPIPSecDriver::SpawnL2TPIPSecVPN(Error* error) {
SLOG(this, 2) << __func__;
std::unique_ptr<ExternalTask> external_task_local(
new ExternalTask(control_,
process_manager_,
weak_ptr_factory_.GetWeakPtr(),
Bind(&L2TPIPSecDriver::OnL2TPIPSecVPNDied,
weak_ptr_factory_.GetWeakPtr())));
vector<string> options;
map<string, string> environment; // No env vars passed.
if (!InitOptions(&options, error)) {
return false;
}
LOG(INFO) << "L2TP/IPSec VPN process options: "
<< base::JoinString(options, " ");
if (external_task_local->Start(
FilePath(kL2TPIPSecVPNPath), options, environment, true, error)) {
external_task_ = std::move(external_task_local);
return true;
}
return false;
}
bool L2TPIPSecDriver::InitOptions(vector<string>* options, Error* error) {
string vpnhost = args()->LookupString(kProviderHostProperty, "");
if (vpnhost.empty()) {
Error::PopulateAndLog(
FROM_HERE, error, Error::kInvalidArguments, "VPN host not specified.");
return false;
}
if (!InitPSKOptions(options, error)) {
return false;
}
if (!InitXauthOptions(options, error)) {
return false;
}
options->push_back(base::StringPrintf("--remote_host=%s", vpnhost.c_str()));
options->push_back(base::StringPrintf("--pppd_plugin=%s",
PPPDaemon::kShimPluginPath));
// Disable pppd from configuring IP addresses, routes, DNS.
options->push_back("--nosystemconfig");
// Accept a PEM CA certificate.
InitPEMOptions(options);
AppendValueOption(kL2tpIpsecClientCertIdProperty,
"--client_cert_id", options);
AppendValueOption(kL2tpIpsecClientCertSlotProperty,
"--client_cert_slot", options);
AppendValueOption(kL2tpIpsecPinProperty, "--user_pin", options);
AppendValueOption(kL2tpIpsecUserProperty, "--user", options);
AppendValueOption(kL2TPIPSecIPSecTimeoutProperty, "--ipsec_timeout", options);
AppendValueOption(kL2TPIPSecLeftProtoPortProperty,
"--leftprotoport", options);
AppendFlag(kL2TPIPSecPFSProperty, "--pfs", "--nopfs", options);
AppendFlag(kL2TPIPSecRekeyProperty, "--rekey", "--norekey", options);
AppendValueOption(kL2TPIPSecRightProtoPortProperty,
"--rightprotoport", options);
AppendFlag(kL2TPIPSecRequireChapProperty,
"--require_chap", "--norequire_chap", options);
AppendFlag(kL2TPIPSecRefusePapProperty,
"--refuse_pap", "--norefuse_pap", options);
AppendFlag(kL2TPIPSecRequireAuthProperty,
"--require_authentication", "--norequire_authentication", options);
AppendFlag(kL2TPIPSecLengthBitProperty,
"--length_bit", "--nolength_bit", options);
AppendFlag(kL2tpIpsecLcpEchoDisabledProperty,
"--noppp_lcp_echo", "--ppp_lcp_echo", options);
AppendValueOption(kL2tpIpsecTunnelGroupProperty, "--tunnel_group", options);
if (SLOG_IS_ON(VPN, 0)) {
options->push_back("--debug");
}
return true;
}
bool L2TPIPSecDriver::InitPSKOptions(vector<string>* options, Error* error) {
string psk = args()->LookupString(kL2tpIpsecPskProperty, "");
if (!psk.empty()) {
if (!base::CreateTemporaryFileInDir(manager()->run_path(), &psk_file_) ||
chmod(psk_file_.value().c_str(), S_IRUSR | S_IWUSR) ||
base::WriteFile(psk_file_, psk.data(), psk.size()) !=
static_cast<int>(psk.size())) {
Error::PopulateAndLog(
FROM_HERE, error, Error::kInternalError, "Unable to setup psk file.");
return false;
}
options->push_back(base::StringPrintf("--psk_file=%s",
psk_file_.value().c_str()));
}
return true;
}
bool L2TPIPSecDriver::InitPEMOptions(vector<string>* options) {
vector<string> ca_certs;
if (args()->ContainsStrings(kL2tpIpsecCaCertPemProperty)) {
ca_certs = args()->GetStrings(kL2tpIpsecCaCertPemProperty);
}
if (ca_certs.empty()) {
return false;
}
FilePath certfile = certificate_file_->CreatePEMFromStrings(ca_certs);
if (certfile.empty()) {
LOG(ERROR) << "Unable to extract certificates from PEM string.";
return false;
}
options->push_back(base::StringPrintf("--server_ca_file=%s",
certfile.value().c_str()));
return true;
}
bool L2TPIPSecDriver::InitXauthOptions(vector<string>* options, Error* error) {
string user = args()->LookupString(kL2tpIpsecXauthUserProperty, "");
string password = args()->LookupString(kL2tpIpsecXauthPasswordProperty, "");
if (user.empty() && password.empty()) {
// Xauth credentials not configured.
return true;
}
if (user.empty() || password.empty()) {
Error::PopulateAndLog(
FROM_HERE, error, Error::kInvalidArguments,
"XAUTH credentials are partially configured.");
return false;
}
string xauth_credentials = user + "\n" + password + "\n";
if (!base::CreateTemporaryFileInDir(manager()->run_path(),
&xauth_credentials_file_) ||
chmod(xauth_credentials_file_.value().c_str(), S_IRUSR | S_IWUSR) ||
base::WriteFile(xauth_credentials_file_, xauth_credentials.data(),
xauth_credentials.size()) !=
static_cast<int>(xauth_credentials.size())) {
Error::PopulateAndLog(
FROM_HERE, error, Error::kInternalError,
"Unable to setup XAUTH credentials file.");
return false;
}
options->push_back(base::StringPrintf("--xauth_credentials_file=%s",
xauth_credentials_file_.value().c_str()));
return true;
}
bool L2TPIPSecDriver::AppendValueOption(
const string& property, const string& option, vector<string>* options) {
string value = args()->LookupString(property, "");
if (!value.empty()) {
options->push_back(base::StringPrintf("%s=%s", option.c_str(),
value.c_str()));
return true;
}
return false;
}
bool L2TPIPSecDriver::AppendFlag(const string& property,
const string& true_option,
const string& false_option,
vector<string>* options) {
string value = args()->LookupString(property, "");
if (!value.empty()) {
options->push_back(value == "true" ? true_option : false_option);
return true;
}
return false;
}
void L2TPIPSecDriver::OnL2TPIPSecVPNDied(pid_t /*pid*/, int status) {
FailService(TranslateExitStatusToFailure(status));
// TODO(petkov): Figure if we need to restart the connection.
}
// static
Service::ConnectFailure L2TPIPSecDriver::TranslateExitStatusToFailure(
int status) {
if (!WIFEXITED(status)) {
return Service::kFailureInternal;
}
switch (WEXITSTATUS(status)) {
case vpn_manager::kServiceErrorResolveHostnameFailed:
return Service::kFailureDNSLookup;
case vpn_manager::kServiceErrorIpsecConnectionFailed:
case vpn_manager::kServiceErrorL2tpConnectionFailed:
case vpn_manager::kServiceErrorPppConnectionFailed:
return Service::kFailureConnect;
case vpn_manager::kServiceErrorIpsecPresharedKeyAuthenticationFailed:
return Service::kFailureIPSecPSKAuth;
case vpn_manager::kServiceErrorIpsecCertificateAuthenticationFailed:
return Service::kFailureIPSecCertAuth;
case vpn_manager::kServiceErrorPppAuthenticationFailed:
return Service::kFailurePPPAuth;
default:
break;
}
return Service::kFailureUnknown;
}
void L2TPIPSecDriver::GetLogin(string* user, string* password) {
LOG(INFO) << "Login requested.";
string user_property =
args()->LookupString(kL2tpIpsecUserProperty, "");
if (user_property.empty()) {
LOG(ERROR) << "User not set.";
return;
}
string password_property =
args()->LookupString(kL2tpIpsecPasswordProperty, "");
if (password_property.empty()) {
LOG(ERROR) << "Password not set.";
return;
}
*user = user_property;
*password = password_property;
}
void L2TPIPSecDriver::Notify(
const string& reason, const map<string, string>& dict) {
LOG(INFO) << "IP configuration received: " << reason;
if (reason == kPPPReasonAuthenticating ||
reason == kPPPReasonAuthenticated) {
// These are uninteresting intermediate states that do not indicate failure.
return;
}
if (reason != kPPPReasonConnect) {
DCHECK_EQ(kPPPReasonDisconnect, reason);
// DestroyLater, rather than while on stack.
external_task_.release()->DestroyLater(dispatcher());
FailService(Service::kFailureUnknown);
return;
}
DeleteTemporaryFiles();
string interface_name = PPPDevice::GetInterfaceName(dict);
int interface_index = device_info_->GetIndex(interface_name);
if (interface_index < 0) {
// TODO(petkov): Consider handling the race when the RTNL notification about
// the new PPP device has not been received yet. We can keep the IP
// configuration and apply it when ClaimInterface is
// invoked. crbug.com/212446.
NOTIMPLEMENTED() << ": No device info for " << interface_name << ".";
return;
}
// There is no IPv6 support for L2TP/IPsec VPN at this moment, so create a
// blackhole route for IPv6 traffic after establishing a IPv4 VPN.
// TODO(benchan): Generalize this when IPv6 support is added.
bool blackhole_ipv6 = true;
if (!device_) {
device_ = ppp_device_factory_->CreatePPPDevice(
control_, dispatcher(), metrics_, manager(), interface_name,
interface_index);
}
device_->SetEnabled(true);
device_->SelectService(service_);
// Reduce MTU to the minimum viable for IPv6, since the IPSec layer consumes
// some variable portion of the payload. Although this system does not yet
// support IPv6, it is a reasonable value to start with, since the minimum
// IPv6 packet size will plausibly be a size any gateway would support, and
// is also larger than the IPv4 minimum size.
device_->UpdateIPConfigFromPPPWithMTU(
dict, blackhole_ipv6, IPConfig::kMinIPv6MTU);
ReportConnectionMetrics();
StopConnectTimeout();
}
bool L2TPIPSecDriver::IsPskRequired() const {
return
const_args()->LookupString(kL2tpIpsecPskProperty, "").empty() &&
const_args()->LookupString(kL2tpIpsecClientCertIdProperty, "").empty();
}
KeyValueStore L2TPIPSecDriver::GetProvider(Error* error) {
SLOG(this, 2) << __func__;
KeyValueStore props = VPNDriver::GetProvider(error);
props.SetBool(kPassphraseRequiredProperty,
args()->LookupString(kL2tpIpsecPasswordProperty, "").empty());
props.SetBool(kL2tpIpsecPskRequiredProperty, IsPskRequired());
return props;
}
void L2TPIPSecDriver::ReportConnectionMetrics() {
metrics_->SendEnumToUMA(
Metrics::kMetricVpnDriver,
Metrics::kVpnDriverL2tpIpsec,
Metrics::kMetricVpnDriverMax);
// We output an enum for each of the authentication types specified,
// even if more than one is set at the same time.
bool has_remote_authentication = false;
if (args()->LookupString(kL2tpIpsecPskProperty, "") != "") {
metrics_->SendEnumToUMA(
Metrics::kMetricVpnRemoteAuthenticationType,
Metrics::kVpnRemoteAuthenticationTypeL2tpIpsecPsk,
Metrics::kMetricVpnRemoteAuthenticationTypeMax);
has_remote_authentication = true;
}
if (!has_remote_authentication) {
metrics_->SendEnumToUMA(
Metrics::kMetricVpnRemoteAuthenticationType,
Metrics::kVpnRemoteAuthenticationTypeL2tpIpsecDefault,
Metrics::kMetricVpnRemoteAuthenticationTypeMax);
}
bool has_user_authentication = false;
if (args()->LookupString(kL2tpIpsecClientCertIdProperty,
"") != "") {
metrics_->SendEnumToUMA(
Metrics::kMetricVpnUserAuthenticationType,
Metrics::kVpnUserAuthenticationTypeL2tpIpsecCertificate,
Metrics::kMetricVpnUserAuthenticationTypeMax);
has_user_authentication = true;
}
if (args()->LookupString(kL2tpIpsecPasswordProperty, "") != "") {
metrics_->SendEnumToUMA(
Metrics::kMetricVpnUserAuthenticationType,
Metrics::kVpnUserAuthenticationTypeL2tpIpsecUsernamePassword,
Metrics::kMetricVpnUserAuthenticationTypeMax);
has_user_authentication = true;
}
if (!has_user_authentication) {
metrics_->SendEnumToUMA(
Metrics::kMetricVpnUserAuthenticationType,
Metrics::kVpnUserAuthenticationTypeL2tpIpsecNone,
Metrics::kMetricVpnUserAuthenticationTypeMax);
}
}
} // namespace shill