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_attachment_set.h"
  23 #include "ipc/ipc_message_utils.h"
  24
  25 namespace IPC {
  26
  27 ChannelWin::State::State(ChannelWin* channel) : is_pending(false) {
  28   memset(&context.overlapped, 0, sizeof(context.overlapped));
  29   context.handler = channel;
  30 }
  31
  32 ChannelWin::State::~State() {
  33   static_assert(offsetof(ChannelWin::State, context) == 0,
  34                 "ChannelWin::State should have context as its first data"
  35                 "member.");
  36 }
  37
  38 ChannelWin::ChannelWin(const IPC::ChannelHandle& channel_handle,
  39                        Mode mode,
  40                        Listener* listener,
  41                        AttachmentBroker* broker)
  42     : ChannelReader(listener),
  43       input_state_(this),
  44       output_state_(this),
  45       peer_pid_(base::kNullProcessId),
  46       waiting_connect_(mode & MODE_SERVER_FLAG),
  47       processing_incoming_(false),
  48       validate_client_(false),
  49       client_secret_(0),
  50       broker_(broker),
  51       weak_factory_(this) {
  52   CreatePipe(channel_handle, mode);
  53 }
  54
  55 ChannelWin::~ChannelWin() {
  56   Close();
  57 }
  58
  59 void ChannelWin::Close() {
  60   if (thread_check_.get())
  61     DCHECK(thread_check_->CalledOnValidThread());
  62
  63   if (input_state_.is_pending || output_state_.is_pending)
  64     CancelIo(pipe_.Get());
  65
  66   // Closing the handle at this point prevents us from issuing more requests
  67   // form OnIOCompleted().
  68   if (pipe_.IsValid())
  69     pipe_.Close();
  70
  71   // Make sure all IO has completed.
  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 ChannelWin::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   if (!prelim_queue_.empty()) {
  90     prelim_queue_.push(message);
  91     return true;
  92   }
  93
  94   if (message->HasBrokerableAttachments() &&
  95       peer_pid_ == base::kNullProcessId) {
  96     prelim_queue_.push(message);
  97     return true;
  98   }
  99
 100   return ProcessMessageForDelivery(message);
 101 }
 102
 103 bool ChannelWin::ProcessMessageForDelivery(Message* message) {
 104   // Sending a brokerable attachment requires a call to Channel::Send(), so
 105   // both Send() and ProcessMessageForDelivery() may be re-entrant. Brokered
 106   // attachments must be sent before the Message itself.
 107   if (message->HasBrokerableAttachments()) {
 108     DCHECK(broker_);
 109     DCHECK(peer_pid_ != base::kNullProcessId);
 110     for (const BrokerableAttachment* attachment :
 111          message->attachment_set()->PeekBrokerableAttachments()) {
 112       if (!broker_->SendAttachmentToProcess(attachment, peer_pid_)) {
 113         delete message;
 114         return false;
 115       }
 116     }
 117   }
 118
 119 #ifdef IPC_MESSAGE_LOG_ENABLED
 120   Logging::GetInstance()->OnSendMessage(message, "");
 121 #endif
 122
 123   message->TraceMessageBegin();
 124
 125   // |output_queue_| takes ownership of |message|.
 126   output_queue_.push(message);
 127   // ensure waiting to write
 128   if (!waiting_connect_) {
 129     if (!output_state_.is_pending) {
 130       if (!ProcessOutgoingMessages(NULL, 0))
 131         return false;
 132     }
 133   }
 134
 135   return true;
 136 }
 137
 138 void ChannelWin::FlushPrelimQueue() {
 139   DCHECK_NE(peer_pid_, base::kNullProcessId);
 140
 141   // Due to the possibly re-entrant nature of ProcessMessageForDelivery(), it
 142   // is critical that |prelim_queue_| appears empty.
 143   std::queue<Message*> prelim_queue;
 144   prelim_queue_.swap(prelim_queue);
 145
 146   while (!prelim_queue.empty()) {
 147     Message* m = prelim_queue.front();
 148     ProcessMessageForDelivery(m);
 149     prelim_queue.pop();
 150   }
 151 }
 152
 153 AttachmentBroker* ChannelWin::GetAttachmentBroker() {
 154   return broker_;
 155 }
 156
 157 base::ProcessId ChannelWin::GetPeerPID() const {
 158   return peer_pid_;
 159 }
 160
 161 base::ProcessId ChannelWin::GetSelfPID() const {
 162   return GetCurrentProcessId();
 163 }
 164
 165 // static
 166 bool ChannelWin::IsNamedServerInitialized(
 167     const std::string& channel_id) {
 168   if (WaitNamedPipe(PipeName(channel_id, NULL).c_str(), 1))
 169     return true;
 170   // If ERROR_SEM_TIMEOUT occurred, the pipe exists but is handling another
 171   // connection.
 172   return GetLastError() == ERROR_SEM_TIMEOUT;
 173 }
 174
 175 ChannelWin::ReadState ChannelWin::ReadData(
 176     char* buffer,
 177     int buffer_len,
 178     int* /* bytes_read */) {
 179   if (!pipe_.IsValid())
 180     return READ_FAILED;
 181
 182   DWORD bytes_read = 0;
 183   BOOL ok = ReadFile(pipe_.Get(), buffer, buffer_len,
 184                      &bytes_read, &input_state_.context.overlapped);
 185   if (!ok) {
 186     DWORD err = GetLastError();
 187     if (err == ERROR_IO_PENDING) {
 188       input_state_.is_pending = true;
 189       return READ_PENDING;
 190     }
 191     LOG(ERROR) << "pipe error: " << err;
 192     return READ_FAILED;
 193   }
 194
 195   // We could return READ_SUCCEEDED here. But the way that this code is
 196   // structured we instead go back to the message loop. Our completion port
 197   // will be signalled even in the "synchronously completed" state.
 198   //
 199   // This allows us to potentially process some outgoing messages and
 200   // interleave other work on this thread when we're getting hammered with
 201   // input messages. Potentially, this could be tuned to be more efficient
 202   // with some testing.
 203   input_state_.is_pending = true;
 204   return READ_PENDING;
 205 }
 206
 207 bool ChannelWin::ShouldDispatchInputMessage(Message* msg) {
 208   // Make sure we get a hello when client validation is required.
 209   if (validate_client_)
 210     return IsHelloMessage(*msg);
 211   return true;
 212 }
 213
 214 bool ChannelWin::GetNonBrokeredAttachments(Message* msg) {
 215   return true;
 216 }
 217
 218 void ChannelWin::HandleInternalMessage(const Message& msg) {
 219   DCHECK_EQ(msg.type(), static_cast<unsigned>(Channel::HELLO_MESSAGE_TYPE));
 220   // The hello message contains one parameter containing the PID.
 221   base::PickleIterator it(msg);
 222   int32 claimed_pid;
 223   bool failed = !it.ReadInt(&claimed_pid);
 224
 225   if (!failed && validate_client_) {
 226     int32 secret;
 227     failed = it.ReadInt(&secret) ? (secret != client_secret_) : true;
 228   }
 229
 230   if (failed) {
 231     NOTREACHED();
 232     Close();
 233     listener()->OnChannelError();
 234     return;
 235   }
 236
 237   peer_pid_ = claimed_pid;
 238   // Validation completed.
 239   validate_client_ = false;
 240
 241   FlushPrelimQueue();
 242
 243   listener()->OnChannelConnected(claimed_pid);
 244 }
 245
 246 base::ProcessId ChannelWin::GetSenderPID() {
 247   return GetPeerPID();
 248 }
 249
 250 bool ChannelWin::IsAttachmentBrokerEndpoint() {
 251   return is_attachment_broker_endpoint();
 252 }
 253
 254 bool ChannelWin::DidEmptyInputBuffers() {
 255   // We don't need to do anything here.
 256   return true;
 257 }
 258
 259 // static
 260 const base::string16 ChannelWin::PipeName(
 261     const std::string& channel_id, int32* secret) {
 262   std::string name("\\\\.\\pipe\\chrome.");
 263
 264   // Prevent the shared secret from ending up in the pipe name.
 265   size_t index = channel_id.find_first_of('\\');
 266   if (index != std::string::npos) {
 267     if (secret)  // Retrieve the secret if asked for.
 268       base::StringToInt(channel_id.substr(index + 1), secret);
 269     return base::ASCIIToUTF16(name.append(channel_id.substr(0, index - 1)));
 270   }
 271
 272   // This case is here to support predictable named pipes in tests.
 273   if (secret)
 274     *secret = 0;
 275   return base::ASCIIToUTF16(name.append(channel_id));
 276 }
 277
 278 bool ChannelWin::CreatePipe(const IPC::ChannelHandle &channel_handle,
 279                             Mode mode) {
 280   DCHECK(!pipe_.IsValid());
 281   base::string16 pipe_name;
 282   // If we already have a valid pipe for channel just copy it.
 283   if (channel_handle.pipe.handle) {
 284     // TODO(rvargas) crbug.com/415294: ChannelHandle should either go away in
 285     // favor of two independent entities (name/file), or it should be a move-
 286     // only type with a base::File member. In any case, this code should not
 287     // call DuplicateHandle.
 288     DCHECK(channel_handle.name.empty());
 289     pipe_name = L"Not Available";  // Just used for LOG
 290     // Check that the given pipe confirms to the specified mode.  We can
 291     // only check for PIPE_TYPE_MESSAGE & PIPE_SERVER_END flags since the
 292     // other flags (PIPE_TYPE_BYTE, and PIPE_CLIENT_END) are defined as 0.
 293     DWORD flags = 0;
 294     GetNamedPipeInfo(channel_handle.pipe.handle, &flags, NULL, NULL, NULL);
 295     DCHECK(!(flags & PIPE_TYPE_MESSAGE));
 296     if (((mode & MODE_SERVER_FLAG) && !(flags & PIPE_SERVER_END)) ||
 297         ((mode & MODE_CLIENT_FLAG) && (flags & PIPE_SERVER_END))) {
 298       LOG(WARNING) << "Inconsistent open mode. Mode :" << mode;
 299       return false;
 300     }
 301     HANDLE local_handle;
 302     if (!DuplicateHandle(GetCurrentProcess(),
 303                          channel_handle.pipe.handle,
 304                          GetCurrentProcess(),
 305                          &local_handle,
 306                          0,
 307                          FALSE,
 308                          DUPLICATE_SAME_ACCESS)) {
 309       LOG(WARNING) << "DuplicateHandle failed. Error :" << GetLastError();
 310       return false;
 311     }
 312     pipe_.Set(local_handle);
 313   } else if (mode & MODE_SERVER_FLAG) {
 314     DCHECK(!channel_handle.pipe.handle);
 315     const DWORD open_mode = PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED |
 316                             FILE_FLAG_FIRST_PIPE_INSTANCE;
 317     pipe_name = PipeName(channel_handle.name, &client_secret_);
 318     validate_client_ = !!client_secret_;
 319     pipe_.Set(CreateNamedPipeW(pipe_name.c_str(),
 320                                open_mode,
 321                                PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
 322                                1,
 323                                Channel::kReadBufferSize,
 324                                Channel::kReadBufferSize,
 325                                5000,
 326                                NULL));
 327   } else if (mode & MODE_CLIENT_FLAG) {
 328     DCHECK(!channel_handle.pipe.handle);
 329     pipe_name = PipeName(channel_handle.name, &client_secret_);
 330     pipe_.Set(CreateFileW(pipe_name.c_str(),
 331                           GENERIC_READ | GENERIC_WRITE,
 332                           0,
 333                           NULL,
 334                           OPEN_EXISTING,
 335                           SECURITY_SQOS_PRESENT | SECURITY_ANONYMOUS |
 336                               FILE_FLAG_OVERLAPPED,
 337                           NULL));
 338   } else {
 339     NOTREACHED();
 340   }
 341
 342   if (!pipe_.IsValid()) {
 343     // If this process is being closed, the pipe may be gone already.
 344     PLOG(WARNING) << "Unable to create pipe \"" << pipe_name << "\" in "
 345                   << (mode & MODE_SERVER_FLAG ? "server" : "client") << " mode";
 346     return false;
 347   }
 348
 349   // Create the Hello message to be sent when Connect is called
 350   scoped_ptr<Message> m(new Message(MSG_ROUTING_NONE,
 351                                     HELLO_MESSAGE_TYPE,
 352                                     IPC::Message::PRIORITY_NORMAL));
 353
 354   // Don't send the secret to the untrusted process, and don't send a secret
 355   // if the value is zero (for IPC backwards compatability).
 356   int32 secret = validate_client_ ? 0 : client_secret_;
 357   if (!m->WriteInt(GetCurrentProcessId()) ||
 358       (secret && !m->WriteUInt32(secret))) {
 359     pipe_.Close();
 360     return false;
 361   }
 362
 363   output_queue_.push(m.release());
 364   return true;
 365 }
 366
 367 bool ChannelWin::Connect() {
 368   DLOG_IF(WARNING, thread_check_.get()) << "Connect called more than once";
 369
 370   if (!thread_check_.get())
 371     thread_check_.reset(new base::ThreadChecker());
 372
 373   if (!pipe_.IsValid())
 374     return false;
 375
 376   base::MessageLoopForIO::current()->RegisterIOHandler(pipe_.Get(), this);
 377
 378   // Check to see if there is a client connected to our pipe...
 379   if (waiting_connect_)
 380     ProcessConnection();
 381
 382   if (!input_state_.is_pending) {
 383     // Complete setup asynchronously. By not setting input_state_.is_pending
 384     // to true, we indicate to OnIOCompleted that this is the special
 385     // initialization signal.
 386     base::MessageLoopForIO::current()->PostTask(
 387         FROM_HERE,
 388         base::Bind(&ChannelWin::OnIOCompleted,
 389                    weak_factory_.GetWeakPtr(),
 390                    &input_state_.context,
 391                    0,
 392                    0));
 393   }
 394
 395   if (!waiting_connect_)
 396     ProcessOutgoingMessages(NULL, 0);
 397   return true;
 398 }
 399
 400 bool ChannelWin::ProcessConnection() {
 401   DCHECK(thread_check_->CalledOnValidThread());
 402   if (input_state_.is_pending)
 403     input_state_.is_pending = false;
 404
 405   // Do we have a client connected to our pipe?
 406   if (!pipe_.IsValid())
 407     return false;
 408
 409   BOOL ok = ConnectNamedPipe(pipe_.Get(), &input_state_.context.overlapped);
 410   DWORD err = GetLastError();
 411   if (ok) {
 412     // Uhm, the API documentation says that this function should never
 413     // return success when used in overlapped mode.
 414     NOTREACHED();
 415     return false;
 416   }
 417
 418   switch (err) {
 419   case ERROR_IO_PENDING:
 420     input_state_.is_pending = true;
 421     break;
 422   case ERROR_PIPE_CONNECTED:
 423     waiting_connect_ = false;
 424     break;
 425   case ERROR_NO_DATA:
 426     // The pipe is being closed.
 427     return false;
 428   default:
 429     NOTREACHED();
 430     return false;
 431   }
 432
 433   return true;
 434 }
 435
 436 bool ChannelWin::ProcessOutgoingMessages(
 437     base::MessageLoopForIO::IOContext* context,
 438     DWORD bytes_written) {
 439   DCHECK(!waiting_connect_);  // Why are we trying to send messages if there's
 440                               // no connection?
 441   DCHECK(thread_check_->CalledOnValidThread());
 442
 443   if (output_state_.is_pending) {
 444     DCHECK(context);
 445     output_state_.is_pending = false;
 446     if (!context || bytes_written == 0) {
 447       DWORD err = GetLastError();
 448       LOG(ERROR) << "pipe error: " << err;
 449       return false;
 450     }
 451     // Message was sent.
 452     CHECK(!output_queue_.empty());
 453     Message* m = output_queue_.front();
 454     output_queue_.pop();
 455     delete m;
 456   }
 457
 458   if (output_queue_.empty())
 459     return true;
 460
 461   if (!pipe_.IsValid())
 462     return false;
 463
 464   // Write to pipe...
 465   Message* m = output_queue_.front();
 466   DCHECK(m->size() <= INT_MAX);
 467   BOOL ok = WriteFile(pipe_.Get(),
 468                       m->data(),
 469                       static_cast<uint32>(m->size()),
 470                       NULL,
 471                       &output_state_.context.overlapped);
 472   if (!ok) {
 473     DWORD write_error = GetLastError();
 474     if (write_error == ERROR_IO_PENDING) {
 475       output_state_.is_pending = true;
 476
 477       DVLOG(2) << "sent pending message @" << m << " on channel @" << this
 478                << " with type " << m->type();
 479
 480       return true;
 481     }
 482     LOG(ERROR) << "pipe error: " << write_error;
 483     return false;
 484   }
 485
 486   DVLOG(2) << "sent message @" << m << " on channel @" << this
 487            << " with type " << m->type();
 488
 489   output_state_.is_pending = true;
 490   return true;
 491 }
 492
 493 void ChannelWin::OnIOCompleted(
 494     base::MessageLoopForIO::IOContext* context,
 495     DWORD bytes_transfered,
 496     DWORD error) {
 497   bool ok = true;
 498   DCHECK(thread_check_->CalledOnValidThread());
 499   if (context == &input_state_.context) {
 500     if (waiting_connect_) {
 501       if (!ProcessConnection())
 502         return;
 503       // We may have some messages queued up to send...
 504       if (!output_queue_.empty() && !output_state_.is_pending)
 505         ProcessOutgoingMessages(NULL, 0);
 506       if (input_state_.is_pending)
 507         return;
 508       // else, fall-through and look for incoming messages...
 509     }
 510
 511     // We don't support recursion through OnMessageReceived yet!
 512     DCHECK(!processing_incoming_);
 513     base::AutoReset<bool> auto_reset_processing_incoming(
 514         &processing_incoming_, true);
 515
 516     // Process the new data.
 517     if (input_state_.is_pending) {
 518       // This is the normal case for everything except the initialization step.
 519       input_state_.is_pending = false;
 520       if (!bytes_transfered) {
 521         ok = false;
 522       } else if (pipe_.IsValid()) {
 523         ok = (AsyncReadComplete(bytes_transfered) != DISPATCH_ERROR);
 524       }
 525     } else {
 526       DCHECK(!bytes_transfered);
 527     }
 528
 529     // Request more data.
 530     if (ok)
 531       ok = (ProcessIncomingMessages() != DISPATCH_ERROR);
 532   } else {
 533     DCHECK(context == &output_state_.context);
 534     CHECK(output_state_.is_pending);
 535     ok = ProcessOutgoingMessages(context, bytes_transfered);
 536   }
 537   if (!ok && pipe_.IsValid()) {
 538     // We don't want to re-enter Close().
 539     Close();
 540     listener()->OnChannelError();
 541   }
 542 }
 543
 544 //------------------------------------------------------------------------------
 545 // Channel's methods
 546
 547 // static
 548 scoped_ptr<Channel> Channel::Create(const IPC::ChannelHandle& channel_handle,
 549                                     Mode mode,
 550                                     Listener* listener,
 551                                     AttachmentBroker* broker) {
 552   return scoped_ptr<Channel>(
 553       new ChannelWin(channel_handle, mode, listener, broker));
 554 }
 555
 556 // static
 557 bool Channel::IsNamedServerInitialized(const std::string& channel_id) {
 558   return ChannelWin::IsNamedServerInitialized(channel_id);
 559 }
 560
 561 // static
 562 std::string Channel::GenerateVerifiedChannelID(const std::string& prefix) {
 563   // Windows pipes can be enumerated by low-privileged processes. So, we
 564   // append a strong random value after the \ character. This value is not
 565   // included in the pipe name, but sent as part of the client hello, to
 566   // hijacking the pipe name to spoof the client.
 567
 568   std::string id = prefix;
 569   if (!id.empty())
 570     id.append(".");
 571
 572   int secret;
 573   do {  // Guarantee we get a non-zero value.
 574     secret = base::RandInt(0, std::numeric_limits<int>::max());
 575   } while (secret == 0);
 576
 577   id.append(GenerateUniqueRandomChannelID());
 578   return id.append(base::StringPrintf("\\%d", secret));
 579 }
 580
 581 }  // namespace IPC