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 bool ChannelWin::DidEmptyInputBuffers() {
 247   // We don't need to do anything here.
 248   return true;
 249 }
 250
 251 // static
 252 const base::string16 ChannelWin::PipeName(
 253     const std::string& channel_id, int32* secret) {
 254   std::string name("\\\\.\\pipe\\chrome.");
 255
 256   // Prevent the shared secret from ending up in the pipe name.
 257   size_t index = channel_id.find_first_of('\\');
 258   if (index != std::string::npos) {
 259     if (secret)  // Retrieve the secret if asked for.
 260       base::StringToInt(channel_id.substr(index + 1), secret);
 261     return base::ASCIIToUTF16(name.append(channel_id.substr(0, index - 1)));
 262   }
 263
 264   // This case is here to support predictable named pipes in tests.
 265   if (secret)
 266     *secret = 0;
 267   return base::ASCIIToUTF16(name.append(channel_id));
 268 }
 269
 270 bool ChannelWin::CreatePipe(const IPC::ChannelHandle &channel_handle,
 271                             Mode mode) {
 272   DCHECK(!pipe_.IsValid());
 273   base::string16 pipe_name;
 274   // If we already have a valid pipe for channel just copy it.
 275   if (channel_handle.pipe.handle) {
 276     // TODO(rvargas) crbug.com/415294: ChannelHandle should either go away in
 277     // favor of two independent entities (name/file), or it should be a move-
 278     // only type with a base::File member. In any case, this code should not
 279     // call DuplicateHandle.
 280     DCHECK(channel_handle.name.empty());
 281     pipe_name = L"Not Available";  // Just used for LOG
 282     // Check that the given pipe confirms to the specified mode.  We can
 283     // only check for PIPE_TYPE_MESSAGE & PIPE_SERVER_END flags since the
 284     // other flags (PIPE_TYPE_BYTE, and PIPE_CLIENT_END) are defined as 0.
 285     DWORD flags = 0;
 286     GetNamedPipeInfo(channel_handle.pipe.handle, &flags, NULL, NULL, NULL);
 287     DCHECK(!(flags & PIPE_TYPE_MESSAGE));
 288     if (((mode & MODE_SERVER_FLAG) && !(flags & PIPE_SERVER_END)) ||
 289         ((mode & MODE_CLIENT_FLAG) && (flags & PIPE_SERVER_END))) {
 290       LOG(WARNING) << "Inconsistent open mode. Mode :" << mode;
 291       return false;
 292     }
 293     HANDLE local_handle;
 294     if (!DuplicateHandle(GetCurrentProcess(),
 295                          channel_handle.pipe.handle,
 296                          GetCurrentProcess(),
 297                          &local_handle,
 298                          0,
 299                          FALSE,
 300                          DUPLICATE_SAME_ACCESS)) {
 301       LOG(WARNING) << "DuplicateHandle failed. Error :" << GetLastError();
 302       return false;
 303     }
 304     pipe_.Set(local_handle);
 305   } else if (mode & MODE_SERVER_FLAG) {
 306     DCHECK(!channel_handle.pipe.handle);
 307     const DWORD open_mode = PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED |
 308                             FILE_FLAG_FIRST_PIPE_INSTANCE;
 309     pipe_name = PipeName(channel_handle.name, &client_secret_);
 310     validate_client_ = !!client_secret_;
 311     pipe_.Set(CreateNamedPipeW(pipe_name.c_str(),
 312                                open_mode,
 313                                PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
 314                                1,
 315                                Channel::kReadBufferSize,
 316                                Channel::kReadBufferSize,
 317                                5000,
 318                                NULL));
 319   } else if (mode & MODE_CLIENT_FLAG) {
 320     DCHECK(!channel_handle.pipe.handle);
 321     pipe_name = PipeName(channel_handle.name, &client_secret_);
 322     pipe_.Set(CreateFileW(pipe_name.c_str(),
 323                           GENERIC_READ | GENERIC_WRITE,
 324                           0,
 325                           NULL,
 326                           OPEN_EXISTING,
 327                           SECURITY_SQOS_PRESENT | SECURITY_ANONYMOUS |
 328                               FILE_FLAG_OVERLAPPED,
 329                           NULL));
 330   } else {
 331     NOTREACHED();
 332   }
 333
 334   if (!pipe_.IsValid()) {
 335     // If this process is being closed, the pipe may be gone already.
 336     PLOG(WARNING) << "Unable to create pipe \"" << pipe_name << "\" in "
 337                   << (mode & MODE_SERVER_FLAG ? "server" : "client") << " mode";
 338     return false;
 339   }
 340
 341   // Create the Hello message to be sent when Connect is called
 342   scoped_ptr<Message> m(new Message(MSG_ROUTING_NONE,
 343                                     HELLO_MESSAGE_TYPE,
 344                                     IPC::Message::PRIORITY_NORMAL));
 345
 346   // Don't send the secret to the untrusted process, and don't send a secret
 347   // if the value is zero (for IPC backwards compatability).
 348   int32 secret = validate_client_ ? 0 : client_secret_;
 349   if (!m->WriteInt(GetCurrentProcessId()) ||
 350       (secret && !m->WriteUInt32(secret))) {
 351     pipe_.Close();
 352     return false;
 353   }
 354
 355   output_queue_.push(m.release());
 356   return true;
 357 }
 358
 359 bool ChannelWin::Connect() {
 360   DLOG_IF(WARNING, thread_check_.get()) << "Connect called more than once";
 361
 362   if (!thread_check_.get())
 363     thread_check_.reset(new base::ThreadChecker());
 364
 365   if (!pipe_.IsValid())
 366     return false;
 367
 368   base::MessageLoopForIO::current()->RegisterIOHandler(pipe_.Get(), this);
 369
 370   // Check to see if there is a client connected to our pipe...
 371   if (waiting_connect_)
 372     ProcessConnection();
 373
 374   if (!input_state_.is_pending) {
 375     // Complete setup asynchronously. By not setting input_state_.is_pending
 376     // to true, we indicate to OnIOCompleted that this is the special
 377     // initialization signal.
 378     base::MessageLoopForIO::current()->PostTask(
 379         FROM_HERE,
 380         base::Bind(&ChannelWin::OnIOCompleted,
 381                    weak_factory_.GetWeakPtr(),
 382                    &input_state_.context,
 383                    0,
 384                    0));
 385   }
 386
 387   if (!waiting_connect_)
 388     ProcessOutgoingMessages(NULL, 0);
 389   return true;
 390 }
 391
 392 bool ChannelWin::ProcessConnection() {
 393   DCHECK(thread_check_->CalledOnValidThread());
 394   if (input_state_.is_pending)
 395     input_state_.is_pending = false;
 396
 397   // Do we have a client connected to our pipe?
 398   if (!pipe_.IsValid())
 399     return false;
 400
 401   BOOL ok = ConnectNamedPipe(pipe_.Get(), &input_state_.context.overlapped);
 402   DWORD err = GetLastError();
 403   if (ok) {
 404     // Uhm, the API documentation says that this function should never
 405     // return success when used in overlapped mode.
 406     NOTREACHED();
 407     return false;
 408   }
 409
 410   switch (err) {
 411   case ERROR_IO_PENDING:
 412     input_state_.is_pending = true;
 413     break;
 414   case ERROR_PIPE_CONNECTED:
 415     waiting_connect_ = false;
 416     break;
 417   case ERROR_NO_DATA:
 418     // The pipe is being closed.
 419     return false;
 420   default:
 421     NOTREACHED();
 422     return false;
 423   }
 424
 425   return true;
 426 }
 427
 428 bool ChannelWin::ProcessOutgoingMessages(
 429     base::MessageLoopForIO::IOContext* context,
 430     DWORD bytes_written) {
 431   DCHECK(!waiting_connect_);  // Why are we trying to send messages if there's
 432                               // no connection?
 433   DCHECK(thread_check_->CalledOnValidThread());
 434
 435   if (output_state_.is_pending) {
 436     DCHECK(context);
 437     output_state_.is_pending = false;
 438     if (!context || bytes_written == 0) {
 439       DWORD err = GetLastError();
 440       LOG(ERROR) << "pipe error: " << err;
 441       return false;
 442     }
 443     // Message was sent.
 444     CHECK(!output_queue_.empty());
 445     Message* m = output_queue_.front();
 446     output_queue_.pop();
 447     delete m;
 448   }
 449
 450   if (output_queue_.empty())
 451     return true;
 452
 453   if (!pipe_.IsValid())
 454     return false;
 455
 456   // Write to pipe...
 457   Message* m = output_queue_.front();
 458   DCHECK(m->size() <= INT_MAX);
 459   BOOL ok = WriteFile(pipe_.Get(),
 460                       m->data(),
 461                       static_cast<uint32>(m->size()),
 462                       NULL,
 463                       &output_state_.context.overlapped);
 464   if (!ok) {
 465     DWORD write_error = GetLastError();
 466     if (write_error == ERROR_IO_PENDING) {
 467       output_state_.is_pending = true;
 468
 469       DVLOG(2) << "sent pending message @" << m << " on channel @" << this
 470                << " with type " << m->type();
 471
 472       return true;
 473     }
 474     LOG(ERROR) << "pipe error: " << write_error;
 475     return false;
 476   }
 477
 478   DVLOG(2) << "sent message @" << m << " on channel @" << this
 479            << " with type " << m->type();
 480
 481   output_state_.is_pending = true;
 482   return true;
 483 }
 484
 485 void ChannelWin::OnIOCompleted(
 486     base::MessageLoopForIO::IOContext* context,
 487     DWORD bytes_transfered,
 488     DWORD error) {
 489   bool ok = true;
 490   DCHECK(thread_check_->CalledOnValidThread());
 491   if (context == &input_state_.context) {
 492     if (waiting_connect_) {
 493       if (!ProcessConnection())
 494         return;
 495       // We may have some messages queued up to send...
 496       if (!output_queue_.empty() && !output_state_.is_pending)
 497         ProcessOutgoingMessages(NULL, 0);
 498       if (input_state_.is_pending)
 499         return;
 500       // else, fall-through and look for incoming messages...
 501     }
 502
 503     // We don't support recursion through OnMessageReceived yet!
 504     DCHECK(!processing_incoming_);
 505     base::AutoReset<bool> auto_reset_processing_incoming(
 506         &processing_incoming_, true);
 507
 508     // Process the new data.
 509     if (input_state_.is_pending) {
 510       // This is the normal case for everything except the initialization step.
 511       input_state_.is_pending = false;
 512       if (!bytes_transfered) {
 513         ok = false;
 514       } else if (pipe_.IsValid()) {
 515         ok = (AsyncReadComplete(bytes_transfered) != DISPATCH_ERROR);
 516       }
 517     } else {
 518       DCHECK(!bytes_transfered);
 519     }
 520
 521     // Request more data.
 522     if (ok)
 523       ok = (ProcessIncomingMessages() != DISPATCH_ERROR);
 524   } else {
 525     DCHECK(context == &output_state_.context);
 526     CHECK(output_state_.is_pending);
 527     ok = ProcessOutgoingMessages(context, bytes_transfered);
 528   }
 529   if (!ok && pipe_.IsValid()) {
 530     // We don't want to re-enter Close().
 531     Close();
 532     listener()->OnChannelError();
 533   }
 534 }
 535
 536 //------------------------------------------------------------------------------
 537 // Channel's methods
 538
 539 // static
 540 scoped_ptr<Channel> Channel::Create(const IPC::ChannelHandle& channel_handle,
 541                                     Mode mode,
 542                                     Listener* listener,
 543                                     AttachmentBroker* broker) {
 544   return scoped_ptr<Channel>(
 545       new ChannelWin(channel_handle, mode, listener, broker));
 546 }
 547
 548 // static
 549 bool Channel::IsNamedServerInitialized(const std::string& channel_id) {
 550   return ChannelWin::IsNamedServerInitialized(channel_id);
 551 }
 552
 553 // static
 554 std::string Channel::GenerateVerifiedChannelID(const std::string& prefix) {
 555   // Windows pipes can be enumerated by low-privileged processes. So, we
 556   // append a strong random value after the \ character. This value is not
 557   // included in the pipe name, but sent as part of the client hello, to
 558   // hijacking the pipe name to spoof the client.
 559
 560   std::string id = prefix;
 561   if (!id.empty())
 562     id.append(".");
 563
 564   int secret;
 565   do {  // Guarantee we get a non-zero value.
 566     secret = base::RandInt(0, std::numeric_limits<int>::max());
 567   } while (secret == 0);
 568
 569   id.append(GenerateUniqueRandomChannelID());
 570   return id.append(base::StringPrintf("\\%d", secret));
 571 }
 572
 573 }  // namespace IPC