Add timeout task to U2F HID state machine

device/u2f/u2f_hid_device.cc

 // Copyright 2017 The Chromium 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 "u2f_hid_device.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "crypto/random.h"
 #include "device/base/device_client.h"
 #include "device/hid/hid_connection.h"
 #include "u2f_apdu_command.h"
 #include "u2f_message.h"
 
 namespace device {
 
 namespace switches {
 static constexpr char kEnableU2fHidTest[] = "enable-u2f-hid-tests";
 }  // namespace switches
 
 U2fHidDevice::U2fHidDevice(scoped_refptr<HidDeviceInfo> device_info)
     : U2fDevice(),
       state_(State::INIT),
       device_info_(device_info),
       weak_factory_(this) {
   channel_id_ = kBroadcastChannel;
 }
 
 U2fHidDevice::~U2fHidDevice() {
   // Cleanup connection
-  if (connection_)
+  if (connection_ && !connection_->closed())
     connection_->Close();
 }
 
 void U2fHidDevice::DeviceTransact(std::unique_ptr<U2fApduCommand> command,
                                   const DeviceCallback& callback) {
   Transition(std::move(command), callback);
 }
 
 void U2fHidDevice::Transition(std::unique_ptr<U2fApduCommand> command,
                               const DeviceCallback& callback) {
   switch (state_) {
-    case State::INIT:
+    case State::INIT: {
       state_ = State::BUSY;
+      ArmTimeout(callback);
       Connect(base::Bind(&U2fHidDevice::OnConnect, weak_factory_.GetWeakPtr(),
                          base::Passed(&command), callback));
       break;
-    case State::CONNECTED:
+    }

[Reilly Grant (use Gerrit), 2017/04/17 23:31:05]

nit: braces unnecessary

[piperc, 2017/04/17 23:43:59]

Acknowledged.

+    case State::CONNECTED: {
       state_ = State::BUSY;
+      ArmTimeout(callback);
       AllocateChannel(std::move(command), callback);
       break;
+    }

[Reilly Grant (use Gerrit), 2017/04/17 23:31:05]

nit: braces unnecessary

[piperc, 2017/04/17 23:43:59]

Acknowledged.

     case State::IDLE: {
       state_ = State::BUSY;
       std::unique_ptr<U2fMessage> msg = U2fMessage::Create(
           channel_id_, U2fMessage::Type::CMD_MSG, command->GetEncodedCommand());
+
+      ArmTimeout(callback);
+      // Write message to the device
       WriteMessage(std::move(msg), true,
                    base::Bind(&U2fHidDevice::MessageReceived,
                               weak_factory_.GetWeakPtr(), callback));
       break;
     }
     case State::BUSY:
       pending_transactions_.push_back({std::move(command), callback});
       break;
     case State::DEVICE_ERROR:
     default:
@@ skipping 12 matching lines @@
 
 void U2fHidDevice::Connect(const HidService::ConnectCallback& callback) {
   HidService* hid_service = DeviceClient::Get()->GetHidService();
 
   hid_service->Connect(device_info_->device_id(), callback);
 }
 
 void U2fHidDevice::OnConnect(std::unique_ptr<U2fApduCommand> command,
                              const DeviceCallback& callback,
                              scoped_refptr<HidConnection> connection) {
+  if (state_ == State::DEVICE_ERROR)
+    return;
+  timeout_callback_.Cancel();
+
   if (connection) {
     connection_ = connection;
     state_ = State::CONNECTED;
   } else {
     state_ = State::DEVICE_ERROR;
   }
   Transition(std::move(command), callback);
 }
 
 void U2fHidDevice::AllocateChannel(std::unique_ptr<U2fApduCommand> command,
                                    const DeviceCallback& callback) {
   // Send random nonce to device to verify received message
   std::vector<uint8_t> nonce(8);
   crypto::RandBytes(nonce.data(), nonce.size());
   std::unique_ptr<U2fMessage> message =
       U2fMessage::Create(channel_id_, U2fMessage::Type::CMD_INIT, nonce);
 
   WriteMessage(
       std::move(message), true,
       base::Bind(&U2fHidDevice::OnAllocateChannel, weak_factory_.GetWeakPtr(),
                  nonce, base::Passed(&command), callback));
 }
 
 void U2fHidDevice::OnAllocateChannel(std::vector<uint8_t> nonce,
                                      std::unique_ptr<U2fApduCommand> command,
                                      const DeviceCallback& callback,
                                      bool success,
                                      std::unique_ptr<U2fMessage> message) {
+  if (state_ == State::DEVICE_ERROR)
+    return;
+  timeout_callback_.Cancel();
+
   if (!success || !message) {
     state_ = State::DEVICE_ERROR;
     Transition(nullptr, callback);
     return;
   }
   // Channel allocation response is defined as:
   // 0: 8 byte nonce
   // 8: 4 byte channel id
   // 12: Protocol version id
   // 13: Major device version
@@ skipping 79 matching lines @@
   std::unique_ptr<U2fMessage> read_message =
       U2fMessage::CreateFromSerializedData(read_buffer);
 
   if (!read_message) {
     std::move(callback).Run(false, nullptr);
     return;
   }
 
   // Received a message from a different channel, so try again
   if (channel_id_ != read_message->channel_id()) {
-    connection_->Read(base::Bind(&U2fHidDevice::OnRead,
-                                 weak_factory_.GetWeakPtr(),
-                                 base::Passed(&callback)));
+    base::ThreadTaskRunnerHandle::Get()->PostTask(

[Reilly Grant (use Gerrit), 2017/04/17 23:31:05]

I think my recent changes to HidConnection make it safe to call Read directly
again.

[piperc, 2017/04/17 23:43:59]

Acknowledged.

+        FROM_HERE,
+        base::Bind(&U2fHidDevice::ReadMessage, weak_factory_.GetWeakPtr(),
+                   base::Passed(&callback)));
     return;
   }
 
   if (read_message->MessageComplete()) {
     std::move(callback).Run(success, std::move(read_message));
     return;
   }
 
   // Continue reading additional packets
   connection_->Read(
@@ skipping 18 matching lines @@
     return;
   }
   connection_->Read(
       base::Bind(&U2fHidDevice::OnReadContinuation, weak_factory_.GetWeakPtr(),
                  base::Passed(&message), base::Passed(&callback)));
 }
 
 void U2fHidDevice::MessageReceived(const DeviceCallback& callback,
                                    bool success,
                                    std::unique_ptr<U2fMessage> message) {
+  if (state_ == State::DEVICE_ERROR)
+    return;
+  timeout_callback_.Cancel();
+
   if (!success) {
     state_ = State::DEVICE_ERROR;
     Transition(nullptr, callback);
     return;
   }
+
   std::unique_ptr<U2fApduResponse> response = nullptr;
   if (message)
     response = U2fApduResponse::CreateFromMessage(message->GetMessagePayload());
   state_ = State::IDLE;
   base::WeakPtr<U2fHidDevice> self = weak_factory_.GetWeakPtr();
   callback.Run(success, std::move(response));
 
   // Executing |callback| may have freed |this|. Check |self| first.
   if (self && !pending_transactions_.empty()) {
     // If any transactions were queued, process the first one
@@ skipping 18 matching lines @@
       std::move(wink_message), true,
       base::Bind(&U2fHidDevice::OnWink, weak_factory_.GetWeakPtr(), callback));
 }
 
 void U2fHidDevice::OnWink(const WinkCallback& callback,
                           bool success,
                           std::unique_ptr<U2fMessage> response) {
   callback.Run();
 }
 
+void U2fHidDevice::ArmTimeout(const DeviceCallback& callback) {
+  DCHECK(timeout_callback_.IsCancelled());
+  timeout_callback_.Reset(base::Bind(&U2fHidDevice::OnTimeout,
+                                     weak_factory_.GetWeakPtr(), callback));
+  // Setup timeout task for 3 seconds
+  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE, timeout_callback_.callback(),
+      base::TimeDelta::FromMilliseconds(3000));
+}
+
+void U2fHidDevice::OnTimeout(const DeviceCallback& callback) {
+  state_ = State::DEVICE_ERROR;
+  Transition(nullptr, callback);
+}
+
 std::string U2fHidDevice::GetId() {
-  std::ostringstream id("hid:");
+  std::ostringstream id("hid:", std::ios::ate);
   id << device_info_->device_id();
   return id.str();
 }
 
 // static
 bool U2fHidDevice::IsTestEnabled() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   return command_line->HasSwitch(switches::kEnableU2fHidTest);
 }
 
 }  // namespace device