vpn-manager: Add l2tp/ipsec vpn manager

ipsec_manager.cc

+// Copyright (c) 2011 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 "vpn-manager/ipsec_manager.h"
+
+#include <arpa/inet.h>  // for inet_ntop and inet_pton
+#include <grp.h>
+#include <netdb.h>  // for getaddrinfo
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "base/eintr_wrapper.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "chromeos/process.h"
+#include "gflags/gflags.h"
+
+#pragma GCC diagnostic ignored "-Wstrict-aliasing"
+DEFINE_int32(ipsec_timeout, 10, "timeout for ipsec to be established");
+DEFINE_string(leftprotoport, "17/1701", "client protocol/port");
+DEFINE_bool(pfs, false, "pfs");
+DEFINE_bool(rekey, false, "rekey");
+DEFINE_string(rightprotoport, "17/1701", "server protocol/port");
+#pragma GCC diagnostic error "-Wstrict-aliasing"
+
+const char kIpsecConnectionName[] = "ipsec_managed";
+const char kIpsecGroupName[] = "ipsec";
+const char kIpsecRunPath[] = "/var/run/ipsec";
+const char kIpsecUpFile[] = "/var/run/ipsec/up";
+const char kIpsecServiceName[] = "ipsec";
+const char kStarterPidFile[] = "/var/run/starter.pid";
+const mode_t kIpsecRunPathMode = (S_IRUSR | S_IWUSR | S_IXUSR |
+                                  S_IRGRP | S_IWGRP | S_IXGRP);
+const char kStatefulContainer[] = "/mnt/stateful_partition/etc";
+
+// Give IPsec layer 2 seconds to shut down before killing it.
+const int kTermTimeout = 2;
+
+using ::chromeos::Process;
+using ::chromeos::ProcessImpl;
+
+IpsecManager::IpsecManager()
+    : ServiceManager(kIpsecServiceName),
+      force_local_address_(NULL),
+      output_fd_(-1),
+      ike_version_(0),
+      ipsec_group_(0),
+      stateful_container_(kStatefulContainer),
+      ipsec_run_path_(kIpsecRunPath),
+      ipsec_up_file_(kIpsecUpFile),
+      starter_pid_file_(kStarterPidFile),
+      starter_(new ProcessImpl) {
+}
+
+bool IpsecManager::Initialize(int ike_version,
+                              const std::string& remote_address,
+                              const std::string& psk_file,
+                              const std::string& server_ca_file,
+                              const std::string& client_key_file,
+                              const std::string& client_cert_file) {
+  if (remote_address.empty()) {
+    LOG(ERROR) << "Missing remote address to IPsec layer";
+    return false;
+  }
+  remote_address_ = remote_address;
+
+  if (psk_file.empty()) {
+    if (server_ca_file.empty() && client_key_file.empty() &&
+        client_cert_file.empty()) {
+      LOG(ERROR) << "Must specify either PSK or certificates for IPsec layer";
+      return false;
+    }
+
+    // Must be a certificate based connection.
+    if (!file_util::PathExists(FilePath(server_ca_file))) {
+      LOG(ERROR) << "Invalid server CA file for IPsec layer: "
+                 << server_ca_file;
+      return false;
+    }
+    server_ca_file_ = server_ca_file;
+
+    if (!file_util::PathExists(FilePath(client_key_file))) {
+      LOG(ERROR) << "Invalid client key file for IPsec layer: "
+                 << client_key_file;
+      return false;
+    }
+    client_key_file_ = client_key_file;
+
+    if (!file_util::PathExists(FilePath(client_cert_file))) {
+      LOG(ERROR) << "Invalid client certificate file for IPsec layer: "
+                 << client_key_file;
+      return false;
+    }
+    client_cert_file_ = client_cert_file;
+  } else {
+    if (!server_ca_file.empty() ||
+        !client_key_file.empty() ||
+        !client_cert_file.empty()) {
+      LOG(ERROR) << "Specified both PSK and certificates for IPsec layer";
+      return false;
+    }
+    if (!file_util::PathExists(FilePath(psk_file))) {
+      LOG(ERROR) << "Invalid PSK file for IPsec layer: " << psk_file;
+      return false;
+    }
+    psk_file_ = psk_file;
+  }
+
+  if (ike_version != 1 && ike_version != 2) {
+    LOG(ERROR) << "Unsupported IKE version" << ike_version;
+    return false;
+  }
+  ike_version_ = ike_version;
+
+  file_util::Delete(FilePath(kIpsecUpFile), false);
+
+  return true;
+}
+
+bool IpsecManager::GetLocalAddressForRemote(const std::string& remote_address_text,

[petkov, 2011/03/11 19:12:53]

80 chars

[kmixter1, 2011/03/11 20:53:04]

Done.

+                                            std::string* local_address_text) {
+  static const char kService[] = "80";
+  if (force_local_address_ != NULL) {
+    *local_address_text = force_local_address_;
+    return true;
+  }
+  struct addrinfo *remote_address;
+  int s = getaddrinfo(remote_address_text.c_str(), kService, NULL,
+                      &remote_address);
+  if (s != 0) {
+    LOG(ERROR) << "getaddrinfo failed: " << gai_strerror(s);
+    return false;
+  }
+  int sock = HANDLE_EINTR(socket(AF_INET, SOCK_DGRAM, 0));
+  if (sock < 0) {
+    LOG(ERROR) << "Unable to create socket";
+    return false;
+  }
+  if (HANDLE_EINTR(
+          connect(sock, remote_address->ai_addr, sizeof(sockaddr))) != 0) {
+    LOG(ERROR) << "Unable to connect";
+    HANDLE_EINTR(close(sock));
+    return false;
+  }
+  bool result = false;
+  struct sockaddr local_address;
+  socklen_t addr_len = sizeof(local_address);
+  char str[INET6_ADDRSTRLEN] = { 0 };
+  if (getsockname(sock, &local_address, &addr_len) != 0) {
+    int saved_errno = errno;
+    LOG(ERROR) << "getsockname failed on socket connecting to "
+               << remote_address_text << ": " << saved_errno;
+    goto error_label;

[petkov, 2011/03/11 19:12:53]

You could define a ScopedSocketCloser and ScopedAddrInfoReleaser and avoid gotos
(and close(sock) above).

[kmixter1, 2011/03/11 20:53:04]

Noted.  If I need to write this kind of code again I will.

+  }
+  // convert local_address to local_address_text.
+  switch (local_address.sa_family) {
+    case AF_INET:
+      if (!inet_ntop(AF_INET, &reinterpret_cast<sockaddr_in*>(
+              &local_address)->sin_addr, str, INET6_ADDRSTRLEN)) {
+        LOG(ERROR) << "inet_ntop failed on " << remote_address_text;
+        goto error_label;
+      }
+      break;
+    case AF_INET6:
+      if (!inet_ntop(AF_INET6, &reinterpret_cast<sockaddr_in6*>(
+              &local_address)->sin6_addr, str, INET6_ADDRSTRLEN)) {
+        LOG(ERROR) << "inet_ntop failed on " << remote_address_text;
+        goto error_label;
+      }
+      break;
+    default:
+      LOG(ERROR) << "Unknown address family converting " << remote_address_text;
+      goto error_label;
+  }
+  *local_address_text = str;
+  LOG(INFO) << "Remote address " << remote_address_text << " has local address "
+            << *local_address_text;
+  result = true;
+
+ error_label:
+  HANDLE_EINTR(close(sock));
+  freeaddrinfo(remote_address);
+  return result;
+}
+
+bool IpsecManager::FormatPsk(const FilePath& input_file,
+                             std::string* formatted) {
+  std::string psk;
+  if (!file_util::ReadFileToString(input_file, &psk)) {
+    LOG(ERROR) << "Unable to read PSK from " << input_file.value();
+    return false;
+  }
+  std::string local_address;
+  if (!GetLocalAddressForRemote(remote_address_, &local_address)) {
+    LOG(ERROR) << "Local IP address could not be determined for PSK mode";
+    return false;
+  }
+  TrimWhitespaceASCII(psk, TRIM_TRAILING, &psk);
+  *formatted =
+      StringPrintf("%s %s : PSK \"%s\"\n", local_address.c_str(),
+                   remote_address_.c_str(), psk.c_str());
+  return true;
+}
+
+void IpsecManager::KillCurrentlyRunning() {
+  if (!file_util::PathExists(FilePath(starter_pid_file_)))
+    return;
+  starter_->ResetPidByFile(starter_pid_file_);
+  if (Process::ProcessExists(starter_->pid()))
+    starter_->Reset(0);
+  else
+    starter_->Release();
+  file_util::Delete(FilePath(starter_pid_file_), false);
+}
+
+bool IpsecManager::StartStarter() {
+  KillCurrentlyRunning();
+  LOG(INFO) << "Starting starter";
+  starter_->AddArg(IPSEC_STARTER);
+  starter_->AddArg("--nofork");
+  starter_->RedirectUsingPipe(STDERR_FILENO, false);
+  if (!starter_->Start()) {
+    LOG(ERROR) << "Starter did not start successfully";
+    return false;
+  }
+  output_fd_ = starter_->GetPipe(STDERR_FILENO);
+  pid_t starter_pid = starter_->pid();
+  LOG(INFO) << "Starter started as pid " << starter_pid;
+  ipsec_prefix_ = StringPrintf("ipsec[%d]: ", starter_pid);
+  return true;
+}
+
+inline void AppendBoolSetting(std::string* config, const char* key,
+                              bool value) {
+  config->append(StringPrintf("\t%s=%s\n", key, value ? "yes" : "no"));
+}
+
+inline void AppendStringSetting(std::string* config, const char* key,
+                                const std::string& value) {
+  config->append(StringPrintf("\t%s=%s\n", key, value.c_str()));
+}
+
+inline void AppendIntSetting(std::string* config, const char* key,
+                             int value) {
+  config->append(StringPrintf("\t%s=%d\n", key, value));
+}
+
+std::string IpsecManager::FormatStarterConfigFile() {
+  std::string config;
+  config.append("config setup\n");
+  if (ike_version_ == 1) {
+    AppendBoolSetting(&config, "charonstart", false);
+  } else {
+    AppendBoolSetting(&config, "plutostart", false);
+  }
+  config.append("conn managed\n");
+  AppendStringSetting(&config, "keyexchange",
+                      ike_version_ == 1 ? "ikev1" : "ikev2");
+  if (!psk_file_.empty()) AppendStringSetting(&config, "authby", "psk");
+  AppendBoolSetting(&config, "pfs", FLAGS_pfs);
+  AppendBoolSetting(&config, "rekey", FLAGS_rekey);
+  AppendStringSetting(&config, "left", "%defaultroute");
+  AppendStringSetting(&config, "leftprotoport", FLAGS_leftprotoport);
+  AppendStringSetting(&config, "leftupdown", IPSEC_UPDOWN);
+  AppendStringSetting(&config, "right", remote_address_);
+  AppendStringSetting(&config, "rightprotoport", FLAGS_rightprotoport);
+  AppendStringSetting(&config, "auto", "start");
+  return config;
+}
+
+bool IpsecManager::SetIpsecGroup(const FilePath& file_path) {
+  return chown(file_path.value().c_str(), getuid(), ipsec_group_) == 0;
+}
+
+bool IpsecManager::WriteConfigFiles() {
+  // We need to keep secrets in /mnt/stateful_partition/etc for now
+  // because pluto loses permissions to /home/chronos before it tries
+  // reading secrets.
+  // TODO(kmixter): write this via a fifo.
+  FilePath secrets_path_ = FilePath(stateful_container_).
+      Append("ipsec.secrets");
+  file_util::Delete(secrets_path_, false);
+  if (!psk_file_.empty()) {
+    std::string formatted;
+    if (!FormatPsk(FilePath(psk_file_), &formatted)) {
+      LOG(ERROR) << "Unable to create secrets contents";
+      return false;
+    }
+    if (!file_util::WriteFile(secrets_path_, formatted.c_str(),
+                              formatted.length()) ||
+        !SetIpsecGroup(secrets_path_)) {
+      LOG(ERROR) << "Unable to write secrets file " << secrets_path_.value();
+      return false;
+    }
+  } else {
+    LOG(FATAL) << "Certificate mode not yet implemented";
+  }
+  FilePath starter_config_path = temp_path()->Append("ipsec.conf");
+  std::string starter_config = FormatStarterConfigFile();
+  if (!file_util::WriteFile(starter_config_path, starter_config.c_str(),
+                            starter_config.size()) ||
+      !SetIpsecGroup(starter_config_path)) {
+    LOG(ERROR) << "Unable to write ipsec config files";
+    return false;
+  }
+  FilePath config_symlink_path = FilePath(stateful_container_).
+      Append("ipsec.conf");
+  // Use unlink to remove the symlink directly since file_util::Delete
+  // cannot delete dangling symlinks.
+  unlink(config_symlink_path.value().c_str());
+  if (file_util::PathExists(config_symlink_path)) {
+    LOG(ERROR) << "Unable to remove existing file "
+               << config_symlink_path.value();
+    return false;
+  }
+  if (symlink(starter_config_path.value().c_str(),
+              config_symlink_path.value().c_str()) < 0) {
+    int saved_errno = errno;
+    LOG(ERROR) << "Unable to symlink config file "
+               << config_symlink_path.value() << " -> "
+               << starter_config_path.value() << ": " << saved_errno;
+    return false;
+  }
+  return true;
+}
+
+bool IpsecManager::CreateIpsecRunDirectory() {
+  if (!file_util::CreateDirectory(FilePath(ipsec_run_path_)) ||
+      !SetIpsecGroup(FilePath(ipsec_run_path_)) ||
+      chmod(ipsec_run_path_.c_str(), kIpsecRunPathMode) != 0) {
+    LOG(ERROR) << "Unable to create " << ipsec_run_path_;
+    return false;
+  }
+  return true;
+}
+
+bool IpsecManager::Start() {
+  if (!ipsec_group_) {
+    struct group group_buffer;
+    struct group* group_result = NULL;
+    char buffer[256];
+    if (getgrnam_r(kIpsecGroupName, &group_buffer, buffer,
+                   sizeof(buffer), &group_result) != 0 || !group_result) {
+      LOG(ERROR) << "Cannot find group id for " << kIpsecGroupName;
+      return false;
+    }
+    ipsec_group_ = group_result->gr_gid;
+    DLOG(INFO) << "Using ipsec group " << ipsec_group_;
+  }
+  if (!WriteConfigFiles())
+    return false;
+  if (!CreateIpsecRunDirectory())
+    return false;
+  if (!StartStarter())
+    return false;
+
+  start_ticks_ = base::TimeTicks::Now();
+
+  return true;
+}
+
+int IpsecManager::Poll() {
+  if (is_running()) return -1;
+  if (start_ticks_.is_null()) return -1;
+  if (!file_util::PathExists(FilePath(ipsec_up_file_))) {
+    if (base::TimeTicks::Now() - start_ticks_ >
+        base::TimeDelta::FromSeconds(FLAGS_ipsec_timeout)) {
+      LOG(ERROR) << "IPsec connection timed out";
+      OnStopped(false);
+      // Poll in 1 second in order to check exit conditions.
+    }
+    return 1000;
+  }
+
+  // This indicates that the connection came up successfully.
+  LOG(INFO) << "IPsec connection now up";
+  OnStarted();
+  return -1;
+}
+
+void IpsecManager::ProcessOutput() {
+  ServiceManager::WriteFdToSyslog(output_fd_, ipsec_prefix_,
+                                  &partial_output_line_);
+}
+
+bool IpsecManager::IsChild(pid_t pid) {
+  return pid == starter_->pid();
+}
+
+void IpsecManager::Stop() {
+  if (starter_->pid() == 0) {
+    return;
+  }
+
+  if (!starter_->Kill(SIGTERM, kTermTimeout)) {
+    starter_->Kill(SIGKILL, 0);
+    OnStopped(true);
+    return;
+  }
+  OnStopped(false);
+}