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| 1 // Copyright 2016 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "remoting/host/security_key/security_key_auth_handler.h" | |
| 6 | |
| 7 #include <cstdint> | |
| 8 #include <map> | |
| 9 #include <memory> | |
| 10 #include <string> | |
| 11 | |
| 12 #include "base/bind.h" | |
| 13 #include "base/location.h" | |
| 14 #include "base/logging.h" | |
| 15 #include "base/memory/weak_ptr.h" | |
| 16 #include "base/strings/stringprintf.h" | |
| 17 #include "base/strings/utf_string_conversions.h" | |
| 18 #include "base/threading/thread_checker.h" | |
| 19 #include "base/threading/thread_task_runner_handle.h" | |
| 20 #include "base/time/time.h" | |
| 21 #include "base/timer/timer.h" | |
| 22 #include "base/win/win_util.h" | |
| 23 #include "ipc/ipc_channel.h" | |
| 24 #include "ipc/ipc_listener.h" | |
| 25 #include "ipc/ipc_message.h" | |
| 26 #include "ipc/ipc_message_macros.h" | |
| 27 #include "remoting/base/logging.h" | |
| 28 #include "remoting/host/chromoting_messages.h" | |
| 29 #include "remoting/host/client_session_details.h" | |
| 30 #include "remoting/host/ipc_util.h" | |
| 31 #include "remoting/host/security_key/security_key_ipc_constants.h" | |
| 32 #include "remoting/host/security_key/security_key_ipc_server.h" | |
| 33 | |
| 34 namespace { | |
| 35 | |
| 36 // The timeout used to disconnect a client from the IPC Server channel if it | |
| 37 // forgets to do so. This ensures the server channel is not blocked forever. | |
| 38 const int kInitialRequestTimeoutSeconds = 5; | |
| 39 | |
| 40 // This value represents the amount of time to wait for a security key request | |
| 41 // from the client before terminating the connection. | |
| 42 const int kSecurityKeyRequestTimeoutSeconds = 60; | |
| 43 | |
| 44 } // namespace | |
| 45 | |
| 46 namespace remoting { | |
| 47 | |
| 48 // Creates an IPC server channel which services IPC clients that want to start | |
| 49 // a security key forwarding session. Once an IPC Client connects to the | |
| 50 // server, the SecurityKeyAuthHandlerWin class will create a new | |
| 51 // SecurityKeyIpcServer instance that will service that request. The new | |
| 52 // instance will exist for the lifetime of the security key request and will be | |
| 53 // assigned a unique IPC channel name and connection id. The channel name is | |
| 54 // sent to the client which should disconnect the IPC server channel and | |
| 55 // connect to the security key forwarding session IPC channel to send/receive | |
| 56 // security key messages. The IPC server channel will then be reset so it can | |
| 57 // can service the next client/request. This system allows multiple security | |
| 58 // key forwarding sessions to occur concurrently. | |
| 59 // TODO(joedow): Update SecurityKeyAuthHandler impls to run on a separate IO | |
| 60 // thread instead of the thread it was created on: crbug.com/591739 | |
| 61 class SecurityKeyAuthHandlerWin : public SecurityKeyAuthHandler, | |
| 62 public IPC::Listener { | |
| 63 public: | |
| 64 explicit SecurityKeyAuthHandlerWin( | |
| 65 ClientSessionDetails* client_session_details); | |
| 66 ~SecurityKeyAuthHandlerWin() override; | |
| 67 | |
| 68 private: | |
| 69 typedef std::map<int, std::unique_ptr<SecurityKeyIpcServer>> ActiveChannels; | |
| 70 | |
| 71 // SecurityKeyAuthHandler interface. | |
| 72 void CreateSecurityKeyConnection() override; | |
| 73 bool IsValidConnectionId(int security_key_connection_id) const override; | |
| 74 void SendClientResponse(int security_key_connection_id, | |
| 75 const std::string& response) override; | |
| 76 void SendErrorAndCloseConnection(int security_key_connection_id) override; | |
| 77 void SetSendMessageCallback(const SendMessageCallback& callback) override; | |
| 78 size_t GetActiveConnectionCountForTest() const override; | |
| 79 void SetRequestTimeoutForTest(base::TimeDelta timeout) override; | |
| 80 | |
| 81 // IPC::Listener implementation. | |
| 82 bool OnMessageReceived(const IPC::Message& message) override; | |
| 83 void OnChannelConnected(int32_t peer_pid) override; | |
| 84 void OnChannelError() override; | |
| 85 | |
| 86 // Creates the IPC server channel and waits for a connection using | |
| 87 // |ipc_server_channel_name_|. | |
| 88 void StartIpcServerChannel(); | |
| 89 | |
| 90 // Restarts the IPC server channel to prepare for another connection. | |
| 91 void RecreateIpcServerChannel(); | |
| 92 | |
| 93 // Closes the IPC channel created for a security key forwarding session. | |
| 94 void CloseSecurityKeyRequestIpcChannel(int connection_id); | |
| 95 | |
| 96 // Returns the IPC Channel instance created for |connection_id|. | |
| 97 ActiveChannels::const_iterator GetChannelForConnectionId( | |
| 98 int connection_id) const; | |
| 99 | |
| 100 // Creates a unique name based on the well-known IPC channel name. | |
| 101 std::string GenerateUniqueChannelName(); | |
| 102 | |
| 103 // Represents the last id assigned to a new security key request IPC channel. | |
| 104 int last_connection_id_ = 0; | |
| 105 | |
| 106 // Sends a security key extension message to the client when called. | |
| 107 SendMessageCallback send_message_callback_; | |
| 108 | |
| 109 // Interface which provides details about the client session. | |
| 110 ClientSessionDetails* client_session_details_ = nullptr; | |
| 111 | |
| 112 // Tracks the IPC channel created for each security key forwarding session. | |
| 113 ActiveChannels active_channels_; | |
| 114 | |
| 115 // The amount of time to wait for a client to process the connection details | |
| 116 // message and disconnect from the IPC server channel before disconnecting it. | |
| 117 base::TimeDelta disconnect_timeout_; | |
| 118 | |
| 119 // Used to recreate the IPC server channel if a client forgets to disconnect. | |
| 120 base::OneShotTimer timer_; | |
| 121 | |
| 122 // IPC Clients connect to this channel first to receive their own IPC | |
| 123 // channel to start a security key forwarding session on. | |
| 124 std::unique_ptr<IPC::Channel> ipc_server_channel_; | |
| 125 | |
| 126 // Ensures SecurityKeyAuthHandlerWin methods are called on the same thread. | |
| 127 base::ThreadChecker thread_checker_; | |
| 128 | |
| 129 base::WeakPtrFactory<SecurityKeyAuthHandlerWin> weak_factory_; | |
| 130 | |
| 131 DISALLOW_COPY_AND_ASSIGN(SecurityKeyAuthHandlerWin); | |
| 132 }; | |
| 133 | |
| 134 std::unique_ptr<SecurityKeyAuthHandler> SecurityKeyAuthHandler::Create( | |
| 135 ClientSessionDetails* client_session_details, | |
| 136 const SendMessageCallback& send_message_callback) { | |
| 137 std::unique_ptr<SecurityKeyAuthHandler> auth_handler( | |
| 138 new SecurityKeyAuthHandlerWin(client_session_details)); | |
| 139 auth_handler->SetSendMessageCallback(send_message_callback); | |
| 140 return auth_handler; | |
| 141 } | |
| 142 | |
| 143 SecurityKeyAuthHandlerWin::SecurityKeyAuthHandlerWin( | |
| 144 ClientSessionDetails* client_session_details) | |
| 145 : client_session_details_(client_session_details), | |
| 146 disconnect_timeout_( | |
| 147 base::TimeDelta::FromSeconds(kInitialRequestTimeoutSeconds)), | |
| 148 weak_factory_(this) { | |
| 149 DCHECK(client_session_details_); | |
| 150 } | |
| 151 | |
| 152 SecurityKeyAuthHandlerWin::~SecurityKeyAuthHandlerWin() {} | |
| 153 | |
| 154 void SecurityKeyAuthHandlerWin::CreateSecurityKeyConnection() { | |
| 155 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 156 StartIpcServerChannel(); | |
| 157 } | |
| 158 | |
| 159 bool SecurityKeyAuthHandlerWin::IsValidConnectionId(int connection_id) const { | |
| 160 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 161 return (GetChannelForConnectionId(connection_id) != active_channels_.end()); | |
| 162 } | |
| 163 | |
| 164 void SecurityKeyAuthHandlerWin::SendClientResponse( | |
| 165 int connection_id, | |
| 166 const std::string& response_data) { | |
| 167 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 168 | |
| 169 ActiveChannels::const_iterator iter = | |
| 170 GetChannelForConnectionId(connection_id); | |
| 171 if (iter == active_channels_.end()) { | |
| 172 HOST_LOG << "Invalid security key connection ID received: " | |
| 173 << connection_id; | |
| 174 return; | |
| 175 } | |
| 176 | |
| 177 if (!iter->second->SendResponse(response_data)) { | |
| 178 CloseSecurityKeyRequestIpcChannel(connection_id); | |
| 179 } | |
| 180 } | |
| 181 | |
| 182 void SecurityKeyAuthHandlerWin::SendErrorAndCloseConnection(int connection_id) { | |
| 183 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 184 | |
| 185 SendClientResponse(connection_id, kSecurityKeyConnectionError); | |
| 186 CloseSecurityKeyRequestIpcChannel(connection_id); | |
| 187 } | |
| 188 | |
| 189 void SecurityKeyAuthHandlerWin::SetSendMessageCallback( | |
| 190 const SendMessageCallback& callback) { | |
| 191 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 192 send_message_callback_ = callback; | |
| 193 } | |
| 194 | |
| 195 size_t SecurityKeyAuthHandlerWin::GetActiveConnectionCountForTest() const { | |
| 196 return active_channels_.size(); | |
| 197 } | |
| 198 | |
| 199 void SecurityKeyAuthHandlerWin::SetRequestTimeoutForTest( | |
| 200 base::TimeDelta timeout) { | |
| 201 disconnect_timeout_ = timeout; | |
| 202 } | |
| 203 | |
| 204 void SecurityKeyAuthHandlerWin::StartIpcServerChannel() { | |
| 205 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 206 | |
| 207 // Create a named pipe owned by the current user (the LocalService account | |
| 208 // (SID: S-1-5-19) when running in the network process) which is available to | |
| 209 // all authenticated users. | |
| 210 // presubmit: allow wstring | |
| 211 std::wstring user_sid; | |
| 212 CHECK(base::win::GetUserSidString(&user_sid)); | |
| 213 std::string user_sid_utf8 = base::WideToUTF8(user_sid); | |
| 214 std::string security_descriptor = base::StringPrintf( | |
| 215 "O:%sG:%sD:(A;;GA;;;AU)", user_sid_utf8.c_str(), user_sid_utf8.c_str()); | |
| 216 | |
| 217 base::win::ScopedHandle pipe; | |
| 218 CHECK(CreateIpcChannel(remoting::GetSecurityKeyIpcChannelName(), | |
| 219 security_descriptor, &pipe)); | |
| 220 ipc_server_channel_ = | |
| 221 IPC::Channel::CreateNamedServer(IPC::ChannelHandle(pipe.Get()), this); | |
| 222 CHECK(ipc_server_channel_->Connect()); | |
| 223 } | |
| 224 | |
| 225 void SecurityKeyAuthHandlerWin::RecreateIpcServerChannel() { | |
| 226 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 227 | |
| 228 timer_.Stop(); | |
| 229 ipc_server_channel_.reset(); | |
| 230 | |
| 231 StartIpcServerChannel(); | |
| 232 } | |
| 233 | |
| 234 void SecurityKeyAuthHandlerWin::CloseSecurityKeyRequestIpcChannel( | |
| 235 int connection_id) { | |
| 236 active_channels_.erase(connection_id); | |
| 237 } | |
| 238 | |
| 239 SecurityKeyAuthHandlerWin::ActiveChannels::const_iterator | |
| 240 SecurityKeyAuthHandlerWin::GetChannelForConnectionId(int connection_id) const { | |
| 241 return active_channels_.find(connection_id); | |
| 242 } | |
| 243 | |
| 244 std::string SecurityKeyAuthHandlerWin::GenerateUniqueChannelName() { | |
| 245 return GetSecurityKeyIpcChannelName() + "." + | |
| 246 IPC::Channel::GenerateUniqueRandomChannelID(); | |
| 247 } | |
| 248 | |
| 249 bool SecurityKeyAuthHandlerWin::OnMessageReceived(const IPC::Message& message) { | |
| 250 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 251 // This class does handle any IPC messages sent by the client. | |
| 252 return false; | |
| 253 } | |
| 254 | |
| 255 void SecurityKeyAuthHandlerWin::OnChannelConnected(int32_t peer_pid) { | |
| 256 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 257 | |
| 258 timer_.Start(FROM_HERE, disconnect_timeout_, | |
| 259 base::Bind(&SecurityKeyAuthHandlerWin::OnChannelError, | |
| 260 base::Unretained(this))); | |
| 261 | |
| 262 // Verify the IPC connection attempt originated from the session we are | |
| 263 // currently remoting. We don't want to service requests from arbitrary | |
| 264 // Windows sessions. | |
| 265 bool close_connection = false; | |
| 266 DWORD peer_session_id; | |
| 267 if (!ProcessIdToSessionId(peer_pid, &peer_session_id)) { | |
| 268 PLOG(ERROR) << "ProcessIdToSessionId() failed"; | |
| 269 close_connection = true; | |
| 270 } else if (peer_session_id != client_session_details_->desktop_session_id()) { | |
| 271 LOG(INFO) << "Ignoring connection attempt from outside remoted session."; | |
| 272 close_connection = true; | |
| 273 } | |
| 274 if (close_connection) { | |
| 275 base::ThreadTaskRunnerHandle::Get()->PostTask( | |
| 276 FROM_HERE, base::Bind(&SecurityKeyAuthHandlerWin::OnChannelError, | |
| 277 weak_factory_.GetWeakPtr())); | |
| 278 return; | |
| 279 } | |
| 280 | |
| 281 int new_connection_id = ++last_connection_id_; | |
| 282 std::unique_ptr<SecurityKeyIpcServer> ipc_server(SecurityKeyIpcServer::Create( | |
| 283 new_connection_id, peer_session_id, disconnect_timeout_, | |
| 284 send_message_callback_, | |
| 285 base::Bind(&SecurityKeyAuthHandlerWin::CloseSecurityKeyRequestIpcChannel, | |
| 286 base::Unretained(this), new_connection_id))); | |
| 287 | |
| 288 std::string unique_channel_name = GenerateUniqueChannelName(); | |
| 289 if (ipc_server->CreateChannel( | |
| 290 unique_channel_name, | |
| 291 base::TimeDelta::FromSeconds(kSecurityKeyRequestTimeoutSeconds))) { | |
| 292 active_channels_[new_connection_id] = std::move(ipc_server); | |
| 293 ipc_server_channel_->Send( | |
| 294 new ChromotingNetworkToRemoteSecurityKeyMsg_ConnectionDetails( | |
| 295 unique_channel_name)); | |
| 296 } | |
| 297 } | |
| 298 | |
| 299 void SecurityKeyAuthHandlerWin::OnChannelError() { | |
| 300 DCHECK(thread_checker_.CalledOnValidThread()); | |
| 301 | |
| 302 // Could be an error, most likely the client disconnected though. Either way | |
| 303 // we should restart the server to prepare for the next connection. | |
| 304 RecreateIpcServerChannel(); | |
| 305 } | |
| 306 | |
| 307 } // namespace remoting | |
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