ipc/ipc_channel_win.cc

   1 // Copyright (c) 2012 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 "ipc/ipc_channel_win.h"
   6
   7 #include <windows.h>
   8
   9 #include "base/auto_reset.h"
  10 #include "base/bind.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/logging.h"
  13 #include "base/pickle.h"
  14 #include "base/process/process_handle.h"
  15 #include "base/rand_util.h"
  16 #include "base/strings/string_number_conversions.h"
  17 #include "base/strings/utf_string_conversions.h"
  18 #include "base/threading/thread_checker.h"
  19 #include "base/win/scoped_handle.h"
  20 #include "ipc/ipc_listener.h"
  21 #include "ipc/ipc_logging.h"
  22 #include "ipc/ipc_message_utils.h"
  23
  24 namespace IPC {
  25
  26 Channel::ChannelImpl::State::State(ChannelImpl* channel) : is_pending(false) {
  27   memset(&context.overlapped, 0, sizeof(context.overlapped));
  28   context.handler = channel;
  29 }
  30
  31 Channel::ChannelImpl::State::~State() {
  32   COMPILE_ASSERT(!offsetof(Channel::ChannelImpl::State, context),
  33                  starts_with_io_context);
  34 }
  35
  36 Channel::ChannelImpl::ChannelImpl(const IPC::ChannelHandle &channel_handle,
  37                                   Mode mode, Listener* listener)
  38     : ChannelReader(listener),
  39       input_state_(this),
  40       output_state_(this),
  41       pipe_(INVALID_HANDLE_VALUE),
  42       peer_pid_(base::kNullProcessId),
  43       waiting_connect_(mode & MODE_SERVER_FLAG),
  44       processing_incoming_(false),
  45       weak_factory_(this),
  46       client_secret_(0),
  47       validate_client_(false) {
  48   CreatePipe(channel_handle, mode);
  49 }
  50
  51 Channel::ChannelImpl::~ChannelImpl() {
  52   Close();
  53 }
  54
  55 void Channel::ChannelImpl::Close() {
  56   if (thread_check_.get()) {
  57     DCHECK(thread_check_->CalledOnValidThread());
  58   }
  59
  60   if (input_state_.is_pending || output_state_.is_pending)
  61     CancelIo(pipe_);
  62
  63   // Closing the handle at this point prevents us from issuing more requests
  64   // form OnIOCompleted().
  65   if (pipe_ != INVALID_HANDLE_VALUE) {
  66     CloseHandle(pipe_);
  67     pipe_ = INVALID_HANDLE_VALUE;
  68   }
  69
  70   // Make sure all IO has completed.
  71   base::Time start = base::Time::Now();
  72   while (input_state_.is_pending || output_state_.is_pending) {
  73     base::MessageLoopForIO::current()->WaitForIOCompletion(INFINITE, this);
  74   }
  75
  76   while (!output_queue_.empty()) {
  77     Message* m = output_queue_.front();
  78     output_queue_.pop();
  79     delete m;
  80   }
  81 }
  82
  83 bool Channel::ChannelImpl::Send(Message* message) {
  84   DCHECK(thread_check_->CalledOnValidThread());
  85   DVLOG(2) << "sending message @" << message << " on channel @" << this
  86            << " with type " << message->type()
  87            << " (" << output_queue_.size() << " in queue)";
  88
  89 #ifdef IPC_MESSAGE_LOG_ENABLED
  90   Logging::GetInstance()->OnSendMessage(message, "");
  91 #endif
  92
  93   message->TraceMessageBegin();
  94   output_queue_.push(message);
  95   // ensure waiting to write
  96   if (!waiting_connect_) {
  97     if (!output_state_.is_pending) {
  98       if (!ProcessOutgoingMessages(NULL, 0))
  99         return false;
 100     }
 101   }
 102
 103   return true;
 104 }
 105
 106 // static
 107 bool Channel::ChannelImpl::IsNamedServerInitialized(
 108     const std::string& channel_id) {
 109   if (WaitNamedPipe(PipeName(channel_id, NULL).c_str(), 1))
 110     return true;
 111   // If ERROR_SEM_TIMEOUT occurred, the pipe exists but is handling another
 112   // connection.
 113   return GetLastError() == ERROR_SEM_TIMEOUT;
 114 }
 115
 116 Channel::ChannelImpl::ReadState Channel::ChannelImpl::ReadData(
 117     char* buffer,
 118     int buffer_len,
 119     int* /* bytes_read */) {
 120   if (INVALID_HANDLE_VALUE == pipe_)
 121     return READ_FAILED;
 122
 123   DWORD bytes_read = 0;
 124   BOOL ok = ReadFile(pipe_, buffer, buffer_len,
 125                      &bytes_read, &input_state_.context.overlapped);
 126   if (!ok) {
 127     DWORD err = GetLastError();
 128     if (err == ERROR_IO_PENDING) {
 129       input_state_.is_pending = true;
 130       return READ_PENDING;
 131     }
 132     LOG(ERROR) << "pipe error: " << err;
 133     return READ_FAILED;
 134   }
 135
 136   // We could return READ_SUCCEEDED here. But the way that this code is
 137   // structured we instead go back to the message loop. Our completion port
 138   // will be signalled even in the "synchronously completed" state.
 139   //
 140   // This allows us to potentially process some outgoing messages and
 141   // interleave other work on this thread when we're getting hammered with
 142   // input messages. Potentially, this could be tuned to be more efficient
 143   // with some testing.
 144   input_state_.is_pending = true;
 145   return READ_PENDING;
 146 }
 147
 148 bool Channel::ChannelImpl::WillDispatchInputMessage(Message* msg) {
 149   // Make sure we get a hello when client validation is required.
 150   if (validate_client_)
 151     return IsHelloMessage(*msg);
 152   return true;
 153 }
 154
 155 void Channel::ChannelImpl::HandleInternalMessage(const Message& msg) {
 156   DCHECK_EQ(msg.type(), static_cast<unsigned>(Channel::HELLO_MESSAGE_TYPE));
 157   // The hello message contains one parameter containing the PID.
 158   PickleIterator it(msg);
 159   int32 claimed_pid;
 160   bool failed = !it.ReadInt(&claimed_pid);
 161
 162   if (!failed && validate_client_) {
 163     int32 secret;
 164     failed = it.ReadInt(&secret) ? (secret != client_secret_) : true;
 165   }
 166
 167   if (failed) {
 168     NOTREACHED();
 169     Close();
 170     listener()->OnChannelError();
 171     return;
 172   }
 173
 174   peer_pid_ = claimed_pid;
 175   // Validation completed.
 176   validate_client_ = false;
 177   listener()->OnChannelConnected(claimed_pid);
 178 }
 179
 180 bool Channel::ChannelImpl::DidEmptyInputBuffers() {
 181   // We don't need to do anything here.
 182   return true;
 183 }
 184
 185 // static
 186 const base::string16 Channel::ChannelImpl::PipeName(
 187     const std::string& channel_id, int32* secret) {
 188   std::string name("\\\\.\\pipe\\chrome.");
 189
 190   // Prevent the shared secret from ending up in the pipe name.
 191   size_t index = channel_id.find_first_of('\\');
 192   if (index != std::string::npos) {
 193     if (secret)  // Retrieve the secret if asked for.
 194       base::StringToInt(channel_id.substr(index + 1), secret);
 195     return base::ASCIIToWide(name.append(channel_id.substr(0, index - 1)));
 196   }
 197
 198   // This case is here to support predictable named pipes in tests.
 199   if (secret)
 200     *secret = 0;
 201   return base::ASCIIToWide(name.append(channel_id));
 202 }
 203
 204 bool Channel::ChannelImpl::CreatePipe(const IPC::ChannelHandle &channel_handle,
 205                                       Mode mode) {
 206   DCHECK_EQ(INVALID_HANDLE_VALUE, pipe_);
 207   base::string16 pipe_name;
 208   // If we already have a valid pipe for channel just copy it.
 209   if (channel_handle.pipe.handle) {
 210     DCHECK(channel_handle.name.empty());
 211     pipe_name = L"Not Available";  // Just used for LOG
 212     // Check that the given pipe confirms to the specified mode.  We can
 213     // only check for PIPE_TYPE_MESSAGE & PIPE_SERVER_END flags since the
 214     // other flags (PIPE_TYPE_BYTE, and PIPE_CLIENT_END) are defined as 0.
 215     DWORD flags = 0;
 216     GetNamedPipeInfo(channel_handle.pipe.handle, &flags, NULL, NULL, NULL);
 217     DCHECK(!(flags & PIPE_TYPE_MESSAGE));
 218     if (((mode & MODE_SERVER_FLAG) && !(flags & PIPE_SERVER_END)) ||
 219         ((mode & MODE_CLIENT_FLAG) && (flags & PIPE_SERVER_END))) {
 220       LOG(WARNING) << "Inconsistent open mode. Mode :" << mode;
 221       return false;
 222     }
 223     if (!DuplicateHandle(GetCurrentProcess(),
 224                          channel_handle.pipe.handle,
 225                          GetCurrentProcess(),
 226                          &pipe_,
 227                          0,
 228                          FALSE,
 229                          DUPLICATE_SAME_ACCESS)) {
 230       LOG(WARNING) << "DuplicateHandle failed. Error :" << GetLastError();
 231       return false;
 232     }
 233   } else if (mode & MODE_SERVER_FLAG) {
 234     DCHECK(!channel_handle.pipe.handle);
 235     const DWORD open_mode = PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED |
 236                             FILE_FLAG_FIRST_PIPE_INSTANCE;
 237     pipe_name = PipeName(channel_handle.name, &client_secret_);
 238     validate_client_ = !!client_secret_;
 239     pipe_ = CreateNamedPipeW(pipe_name.c_str(),
 240                              open_mode,
 241                              PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
 242                              1,
 243                              Channel::kReadBufferSize,
 244                              Channel::kReadBufferSize,
 245                              5000,
 246                              NULL);
 247   } else if (mode & MODE_CLIENT_FLAG) {
 248     DCHECK(!channel_handle.pipe.handle);
 249     pipe_name = PipeName(channel_handle.name, &client_secret_);
 250     pipe_ = CreateFileW(pipe_name.c_str(),
 251                         GENERIC_READ | GENERIC_WRITE,
 252                         0,
 253                         NULL,
 254                         OPEN_EXISTING,
 255                         SECURITY_SQOS_PRESENT | SECURITY_IDENTIFICATION |
 256                             FILE_FLAG_OVERLAPPED,
 257                         NULL);
 258   } else {
 259     NOTREACHED();
 260   }
 261
 262   if (pipe_ == INVALID_HANDLE_VALUE) {
 263     // If this process is being closed, the pipe may be gone already.
 264     LOG(WARNING) << "Unable to create pipe \"" << pipe_name <<
 265                     "\" in " << (mode & MODE_SERVER_FLAG ? "server" : "client")
 266                     << " mode. Error :" << GetLastError();
 267     return false;
 268   }
 269
 270   // Create the Hello message to be sent when Connect is called
 271   scoped_ptr<Message> m(new Message(MSG_ROUTING_NONE,
 272                                     HELLO_MESSAGE_TYPE,
 273                                     IPC::Message::PRIORITY_NORMAL));
 274
 275   // Don't send the secret to the untrusted process, and don't send a secret
 276   // if the value is zero (for IPC backwards compatability).
 277   int32 secret = validate_client_ ? 0 : client_secret_;
 278   if (!m->WriteInt(GetCurrentProcessId()) ||
 279       (secret && !m->WriteUInt32(secret))) {
 280     CloseHandle(pipe_);
 281     pipe_ = INVALID_HANDLE_VALUE;
 282     return false;
 283   }
 284
 285   output_queue_.push(m.release());
 286   return true;
 287 }
 288
 289 bool Channel::ChannelImpl::Connect() {
 290   DLOG_IF(WARNING, thread_check_.get()) << "Connect called more than once";
 291
 292   if (!thread_check_.get())
 293     thread_check_.reset(new base::ThreadChecker());
 294
 295   if (pipe_ == INVALID_HANDLE_VALUE)
 296     return false;
 297
 298   base::MessageLoopForIO::current()->RegisterIOHandler(pipe_, this);
 299
 300   // Check to see if there is a client connected to our pipe...
 301   if (waiting_connect_)
 302     ProcessConnection();
 303
 304   if (!input_state_.is_pending) {
 305     // Complete setup asynchronously. By not setting input_state_.is_pending
 306     // to true, we indicate to OnIOCompleted that this is the special
 307     // initialization signal.
 308     base::MessageLoopForIO::current()->PostTask(
 309         FROM_HERE,
 310         base::Bind(&Channel::ChannelImpl::OnIOCompleted,
 311                    weak_factory_.GetWeakPtr(),
 312                    &input_state_.context,
 313                    0,
 314                    0));
 315   }
 316
 317   if (!waiting_connect_)
 318     ProcessOutgoingMessages(NULL, 0);
 319   return true;
 320 }
 321
 322 bool Channel::ChannelImpl::ProcessConnection() {
 323   DCHECK(thread_check_->CalledOnValidThread());
 324   if (input_state_.is_pending)
 325     input_state_.is_pending = false;
 326
 327   // Do we have a client connected to our pipe?
 328   if (INVALID_HANDLE_VALUE == pipe_)
 329     return false;
 330
 331   BOOL ok = ConnectNamedPipe(pipe_, &input_state_.context.overlapped);
 332
 333   DWORD err = GetLastError();
 334   if (ok) {
 335     // Uhm, the API documentation says that this function should never
 336     // return success when used in overlapped mode.
 337     NOTREACHED();
 338     return false;
 339   }
 340
 341   switch (err) {
 342   case ERROR_IO_PENDING:
 343     input_state_.is_pending = true;
 344     break;
 345   case ERROR_PIPE_CONNECTED:
 346     waiting_connect_ = false;
 347     break;
 348   case ERROR_NO_DATA:
 349     // The pipe is being closed.
 350     return false;
 351   default:
 352     NOTREACHED();
 353     return false;
 354   }
 355
 356   return true;
 357 }
 358
 359 bool Channel::ChannelImpl::ProcessOutgoingMessages(
 360     base::MessageLoopForIO::IOContext* context,
 361     DWORD bytes_written) {
 362   DCHECK(!waiting_connect_);  // Why are we trying to send messages if there's
 363                               // no connection?
 364   DCHECK(thread_check_->CalledOnValidThread());
 365
 366   if (output_state_.is_pending) {
 367     DCHECK(context);
 368     output_state_.is_pending = false;
 369     if (!context || bytes_written == 0) {
 370       DWORD err = GetLastError();
 371       LOG(ERROR) << "pipe error: " << err;
 372       return false;
 373     }
 374     // Message was sent.
 375     CHECK(!output_queue_.empty());
 376     Message* m = output_queue_.front();
 377     output_queue_.pop();
 378     delete m;
 379   }
 380
 381   if (output_queue_.empty())
 382     return true;
 383
 384   if (INVALID_HANDLE_VALUE == pipe_)
 385     return false;
 386
 387   // Write to pipe...
 388   Message* m = output_queue_.front();
 389   DCHECK(m->size() <= INT_MAX);
 390   BOOL ok = WriteFile(pipe_,
 391                       m->data(),
 392                       static_cast<int>(m->size()),
 393                       &bytes_written,
 394                       &output_state_.context.overlapped);
 395   if (!ok) {
 396     DWORD err = GetLastError();
 397     if (err == ERROR_IO_PENDING) {
 398       output_state_.is_pending = true;
 399
 400       DVLOG(2) << "sent pending message @" << m << " on channel @" << this
 401                << " with type " << m->type();
 402
 403       return true;
 404     }
 405     LOG(ERROR) << "pipe error: " << err;
 406     return false;
 407   }
 408
 409   DVLOG(2) << "sent message @" << m << " on channel @" << this
 410            << " with type " << m->type();
 411
 412   output_state_.is_pending = true;
 413   return true;
 414 }
 415
 416 void Channel::ChannelImpl::OnIOCompleted(
 417     base::MessageLoopForIO::IOContext* context,
 418     DWORD bytes_transfered,
 419     DWORD error) {
 420   bool ok = true;
 421   DCHECK(thread_check_->CalledOnValidThread());
 422   if (context == &input_state_.context) {
 423     if (waiting_connect_) {
 424       if (!ProcessConnection())
 425         return;
 426       // We may have some messages queued up to send...
 427       if (!output_queue_.empty() && !output_state_.is_pending)
 428         ProcessOutgoingMessages(NULL, 0);
 429       if (input_state_.is_pending)
 430         return;
 431       // else, fall-through and look for incoming messages...
 432     }
 433
 434     // We don't support recursion through OnMessageReceived yet!
 435     DCHECK(!processing_incoming_);
 436     base::AutoReset<bool> auto_reset_processing_incoming(
 437         &processing_incoming_, true);
 438
 439     // Process the new data.
 440     if (input_state_.is_pending) {
 441       // This is the normal case for everything except the initialization step.
 442       input_state_.is_pending = false;
 443       if (!bytes_transfered)
 444         ok = false;
 445       else if (pipe_ != INVALID_HANDLE_VALUE)
 446         ok = AsyncReadComplete(bytes_transfered);
 447     } else {
 448       DCHECK(!bytes_transfered);
 449     }
 450
 451     // Request more data.
 452     if (ok)
 453       ok = ProcessIncomingMessages();
 454   } else {
 455     DCHECK(context == &output_state_.context);
 456     ok = ProcessOutgoingMessages(context, bytes_transfered);
 457   }
 458   if (!ok && INVALID_HANDLE_VALUE != pipe_) {
 459     // We don't want to re-enter Close().
 460     Close();
 461     listener()->OnChannelError();
 462   }
 463 }
 464
 465 //------------------------------------------------------------------------------
 466 // Channel's methods simply call through to ChannelImpl.
 467 Channel::Channel(const IPC::ChannelHandle &channel_handle, Mode mode,
 468                  Listener* listener)
 469     : channel_impl_(new ChannelImpl(channel_handle, mode, listener)) {
 470 }
 471
 472 Channel::~Channel() {
 473   delete channel_impl_;
 474 }
 475
 476 bool Channel::Connect() {
 477   return channel_impl_->Connect();
 478 }
 479
 480 void Channel::Close() {
 481   if (channel_impl_)
 482     channel_impl_->Close();
 483 }
 484
 485 base::ProcessId Channel::peer_pid() const {
 486   return channel_impl_->peer_pid();
 487 }
 488
 489 bool Channel::Send(Message* message) {
 490   return channel_impl_->Send(message);
 491 }
 492
 493 // static
 494 bool Channel::IsNamedServerInitialized(const std::string& channel_id) {
 495   return ChannelImpl::IsNamedServerInitialized(channel_id);
 496 }
 497
 498 // static
 499 std::string Channel::GenerateVerifiedChannelID(const std::string& prefix) {
 500   // Windows pipes can be enumerated by low-privileged processes. So, we
 501   // append a strong random value after the \ character. This value is not
 502   // included in the pipe name, but sent as part of the client hello, to
 503   // hijacking the pipe name to spoof the client.
 504
 505   std::string id = prefix;
 506   if (!id.empty())
 507     id.append(".");
 508
 509   int secret;
 510   do {  // Guarantee we get a non-zero value.
 511     secret = base::RandInt(0, std::numeric_limits<int>::max());
 512   } while (secret == 0);
 513
 514   id.append(GenerateUniqueRandomChannelID());
 515   return id.append(base::StringPrintf("\\%d", secret));
 516 }
 517
 518 }  // namespace IPC