Use event source-id to filter out remote CRD input

During a CRD session input can come from 2 sources:
   - The remote user (through CRD).
   - The local user.

All remote input is blocked for 2 seconds when local input is detected,
because we do not want the remote user to steal control of the local user.

Previously this was detected by remembering the location of all remote input,
and then monitoring all local input and filtering out the echos of the
remote input.
However this is not 100% accurate, so in this CL I introduce a system
to use the event's source-id to filter out the echos of the remote
commands.

Bug: b/208370410
Test: manually deployed and tested
Change-Id: I1dfd2afe0ebcd611219509a64b9f7f7bc3faac2a
Cq-Include-Trybots: luci.chrome.try:linux-chromeos-chrome
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3440148
Reviewed-by: Ben Franz <bfranz@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Auto-Submit: Jeroen Dhollander <jeroendh@google.com>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/main@{#987305}

remoting/host/client_session.cc

@@ -105,11 +105,11 @@ ClientSession::ClientSession(
   extension_manager_ =
       std::make_unique<HostExtensionSessionManager>(extensions, this);
 
-#if BUILDFLAG(IS_WIN)
-  // LocalInputMonitorWin filters out an echo of the injected input before it
-  // reaches |remote_input_filter_|.
+#if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_CHROMEOS)
+  // LocalMouseInputMonitorWin and LocalPointerInputMonitorChromeos filter out
+  // an echo of the injected input before it reaches |remote_input_filter_|.
   remote_input_filter_.SetExpectLocalEcho(false);
-#endif  // BUILDFLAG(IS_WIN)
+#endif  // BUILDFLAG(IS_WIN) || BUILDFLAG(IS_CHROMEOS)
 }
 
 ClientSession::~ClientSession() {

remoting/host/client_session_unittest.cc

@@ -600,7 +600,7 @@ TEST_F(ClientSessionTest, LocalInputTest) {
 
   connection_->input_stub()->InjectMouseEvent(MakeMouseMoveEvent(100, 101));
 
-#if !BUILDFLAG(IS_WIN)
+#if !BUILDFLAG(IS_WIN) && !BUILDFLAG(IS_CHROMEOS)
   // The OS echoes the injected event back.
   client_session_->OnLocalPointerMoved(webrtc::DesktopVector(100, 101),
                                        ui::ET_MOUSE_MOVED);
@@ -617,7 +617,7 @@ TEST_F(ClientSessionTest, LocalInputTest) {
   connection_->input_stub()->InjectMouseEvent(MakeMouseMoveEvent(300, 301));
 
   // Verify that we've received correct set of mouse events.
-  EXPECT_EQ(2U, mouse_events.size());
+  ASSERT_EQ(2U, mouse_events.size());
   EXPECT_THAT(mouse_events[0], EqualsMouseMoveEvent(100, 101));
   EXPECT_THAT(mouse_events[1], EqualsMouseMoveEvent(200, 201));
 

remoting/host/input_injector_chromeos.cc

@@ -93,6 +93,7 @@ class SystemInputInjectorStub : public ui::SystemInputInjector {
   ~SystemInputInjectorStub() override = default;
 
   // SystemInputInjector implementation:
+  void SetDeviceId(int device_id) override {}
   void MoveCursorTo(const gfx::PointF& location) override {}
   void InjectMouseButton(ui::EventFlags button, bool down) override {}
   void InjectMouseWheel(int delta_x, int delta_y) override {}
@@ -232,6 +233,8 @@ void InputInjectorChromeos::Core::Start(
   }
   DCHECK(delegate_);
 
+  delegate_->SetDeviceId(ui::ED_REMOTE_INPUT_DEVICE);
+
   // Implemented by remoting::ClipboardAura.
   clipboard_ = Clipboard::Create();
   clipboard_->Start(std::move(client_clipboard));

remoting/host/input_monitor/local_keyboard_input_monitor_chromeos.cc

@@ -22,6 +22,10 @@ namespace remoting {
 
 namespace {
 
+bool IsInjectedByCrd(const ui::PlatformEvent& event) {
+  return event->source_device_id() == ui::ED_REMOTE_INPUT_DEVICE;
+}
+
 class LocalKeyboardInputMonitorChromeos : public LocalKeyboardInputMonitor {
  public:
   LocalKeyboardInputMonitorChromeos(
@@ -105,6 +109,11 @@ void LocalKeyboardInputMonitorChromeos::Core::WillProcessEvent(
 
 void LocalKeyboardInputMonitorChromeos::Core::DidProcessEvent(
     const ui::PlatformEvent& event) {
+  // Do not pass on events remotely injected by CRD, as we're supposed to
+  // monitor for local input only.
+  if (IsInjectedByCrd(event))
+    return;
+
   ui::EventType type = ui::EventTypeFromNative(event);
   if (type == ui::ET_KEY_PRESSED) {
     ui::DomCode dom_code = ui::CodeFromNative(event);

remoting/host/input_monitor/local_pointer_input_monitor_chromeos.cc

@@ -14,6 +14,7 @@
 #include "remoting/host/chromeos/point_transformer.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_geometry.h"
 #include "ui/events/event.h"
+#include "ui/events/event_constants.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/platform/platform_event_observer.h"
 #include "ui/events/platform/platform_event_source.h"
@@ -22,6 +23,10 @@ namespace remoting {
 
 namespace {
 
+bool IsInjectedByCrd(const ui::PlatformEvent& event) {
+  return event->source_device_id() == ui::ED_REMOTE_INPUT_DEVICE;
+}
+
 class LocalPointerInputMonitorChromeos : public LocalPointerInputMonitor {
  public:
   LocalPointerInputMonitorChromeos(
@@ -113,6 +118,11 @@ void LocalPointerInputMonitorChromeos::Core::WillProcessEvent(
 
 void LocalPointerInputMonitorChromeos::Core::DidProcessEvent(
     const ui::PlatformEvent& event) {
+  // Do not pass on events remotely injected by CRD, as we're supposed to
+  // monitor for local input only.
+  if (IsInjectedByCrd(event))
+    return;
+
   ui::EventType type = ui::EventTypeFromNative(event);
   if (type == ui::ET_MOUSE_MOVED || type == ui::ET_TOUCH_MOVED) {
     HandlePointerMove(event, type);

ui/chromeos/events/event_rewriter_chromeos.cc

@@ -1061,8 +1061,10 @@ bool EventRewriterChromeOS::IsLastKeyboardOfType(DeviceType device_type) const {
 
 EventRewriterChromeOS::DeviceType EventRewriterChromeOS::GetLastKeyboardType()
     const {
-  if (last_keyboard_device_id_ == ED_UNKNOWN_DEVICE)
+  if ((last_keyboard_device_id_ == ED_UNKNOWN_DEVICE) ||
+      (last_keyboard_device_id_ == ED_REMOTE_INPUT_DEVICE)) {
     return kDeviceUnknown;
+  }
 
   const auto iter = device_id_to_info_.find(last_keyboard_device_id_);
   if (iter == device_id_to_info_.end()) {

ui/events/event_constants.h

@@ -177,8 +177,12 @@ enum class EventMomentumPhase {
   BLOCKED,
 };
 
-// Device ID for Touch and Key Events.
-enum EventDeviceId { ED_UNKNOWN_DEVICE = -1 };
+enum EventDeviceId {
+  // Device ID for Touch, Mouse and Key Events.
+  ED_UNKNOWN_DEVICE = -1,
+  // Device ID for events injected through a remote connection (like CRD).
+  ED_REMOTE_INPUT_DEVICE = -2,
+};
 
 // Pointing device type.
 enum class EventPointerType : int {

ui/events/ozone/evdev/input_injector_evdev.cc

@@ -19,19 +19,17 @@
 
 namespace ui {
 
-namespace {
-
-const int kDeviceIdForInjection = -1;
-
-}  // namespace
-
 InputInjectorEvdev::InputInjectorEvdev(
     std::unique_ptr<DeviceEventDispatcherEvdev> dispatcher,
     CursorDelegateEvdev* cursor)
     : cursor_(cursor), dispatcher_(std::move(dispatcher)) {}
 
 InputInjectorEvdev::~InputInjectorEvdev() = default;
 
+void InputInjectorEvdev::SetDeviceId(int device_id) {
+  device_id_ = device_id;
+}
+
 void InputInjectorEvdev::InjectMouseButton(EventFlags button, bool down) {
   unsigned int code;
   switch (button) {
@@ -50,15 +48,15 @@ void InputInjectorEvdev::InjectMouseButton(EventFlags button, bool down) {
   }
 
   dispatcher_->DispatchMouseButtonEvent(MouseButtonEventParams(
-      kDeviceIdForInjection, EF_NONE, cursor_->GetLocation(), code, down,
+      device_id_, EF_NONE, cursor_->GetLocation(), code, down,
       MouseButtonMapType::kNone, PointerDetails(EventPointerType::kMouse),
       EventTimeForNow()));
 }
 
 void InputInjectorEvdev::InjectMouseWheel(int delta_x, int delta_y) {
   dispatcher_->DispatchMouseWheelEvent(MouseWheelEventParams(
-      kDeviceIdForInjection, cursor_->GetLocation(),
-      gfx::Vector2d(delta_x, delta_y), EventTimeForNow()));
+      device_id_, cursor_->GetLocation(), gfx::Vector2d(delta_x, delta_y),
+      EventTimeForNow()));
 }
 
 void InputInjectorEvdev::MoveCursorTo(const gfx::PointF& location) {
@@ -76,7 +74,7 @@ void InputInjectorEvdev::MoveCursorTo(const gfx::PointF& location) {
   const int event_flags = EF_NOT_SUITABLE_FOR_MOUSE_WARPING;
 
   dispatcher_->DispatchMouseMoveEvent(MouseMoveEventParams(
-      kDeviceIdForInjection, event_flags, cursor_->GetLocation(),
+      device_id_, event_flags, cursor_->GetLocation(),
       nullptr /* ordinal_delta */, PointerDetails(EventPointerType::kMouse),
       EventTimeForNow()));
 }
@@ -88,9 +86,9 @@ void InputInjectorEvdev::InjectKeyEvent(DomCode physical_key,
     return;
 
   int evdev_code = KeycodeConverter::DomCodeToEvdevCode(physical_key);
-  dispatcher_->DispatchKeyEvent(KeyEventParams(
-      kDeviceIdForInjection, ui::EF_NONE, evdev_code, 0 /*scan_code*/, down,
-      suppress_auto_repeat, EventTimeForNow()));
+  dispatcher_->DispatchKeyEvent(
+      KeyEventParams(device_id_, EF_NONE, evdev_code, 0 /*scan_code*/, down,
+                     suppress_auto_repeat, EventTimeForNow()));
 }
 
 }  // namespace ui

ui/events/ozone/evdev/input_injector_evdev.h

@@ -6,6 +6,7 @@
 #define UI_EVENTS_OZONE_EVDEV_INPUT_INJECTOR_EVDEV_H_
 
 #include "base/component_export.h"
+#include "ui/events/event_constants.h"
 #include "ui/events/ozone/evdev/event_dispatch_callback.h"
 #include "ui/ozone/public/system_input_injector.h"
 
@@ -25,6 +26,7 @@ class COMPONENT_EXPORT(EVDEV) InputInjectorEvdev : public SystemInputInjector {
   ~InputInjectorEvdev() override;
 
   // SystemInputInjector implementation.
+  void SetDeviceId(int device_id) override;
   void InjectMouseButton(EventFlags button, bool down) override;
   void InjectMouseWheel(int delta_x, int delta_y) override;
   void MoveCursorTo(const gfx::PointF& location) override;
@@ -36,6 +38,8 @@ class COMPONENT_EXPORT(EVDEV) InputInjectorEvdev : public SystemInputInjector {
   // Shared cursor state.
   CursorDelegateEvdev* const cursor_;
 
+  int device_id_ = ED_UNKNOWN_DEVICE;
+
   // Interface for dispatching events.
   const std::unique_ptr<DeviceEventDispatcherEvdev> dispatcher_;
 };

ui/ozone/public/system_input_injector.h

@@ -19,12 +19,16 @@ namespace ui {
 // native events.
 class COMPONENT_EXPORT(OZONE) SystemInputInjector {
  public:
-  SystemInputInjector() {}
+  SystemInputInjector() = default;
 
   SystemInputInjector(const SystemInputInjector&) = delete;
   SystemInputInjector& operator=(const SystemInputInjector&) = delete;
 
-  virtual ~SystemInputInjector() {}
+  virtual ~SystemInputInjector() = default;
+
+  // Set the device id that will be used for all the generated events.
+  // The device id is set to |ui::ED_UNKNOWN_DEVICE| by default.
+  virtual void SetDeviceId(int device_id) = 0;
 
   // Moves the cursor on the screen and generates the corresponding MouseMove or
   // MouseDragged event.  |location| is in physical screen coordinates,