Milestone 5: deliver embedded RDP sessions and lifecycle hardening

third_party/FreeRDP/channels/rdpecam/server/CMakeLists.txt

@@ -0,0 +1,24 @@
+# FreeRDP: A Remote Desktop Protocol Implementation
+# FreeRDP cmake build script
+#
+# Copyright 2022 Pascal Nowack <Pascal.Nowack@gmx.de>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+define_channel_server("rdpecam")
+
+set(${MODULE_PREFIX}_SRCS camera_device_enumerator_main.c camera_device_main.c)
+
+set(${MODULE_PREFIX}_LIBS freerdp)
+
+add_channel_server_library(${MODULE_PREFIX} ${MODULE_NAME} ${CHANNEL_NAME} FALSE "DVCPluginEntry")

third_party/FreeRDP/channels/rdpecam/server/camera_device_enumerator_main.c

@@ -0,0 +1,627 @@
+/**
+ * FreeRDP: A Remote Desktop Protocol Implementation
+ * Video Capture Virtual Channel Extension
+ *
+ * Copyright 2022 Pascal Nowack <Pascal.Nowack@gmx.de>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	 http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <winpr/cast.h>
+
+#include <freerdp/config.h>
+
+#include <freerdp/freerdp.h>
+#include <freerdp/channels/log.h>
+#include <freerdp/server/rdpecam-enumerator.h>
+
+#include "rdpecam-utils.h"
+
+#define TAG CHANNELS_TAG("rdpecam-enumerator.server")
+
+typedef enum
+{
+	ENUMERATOR_INITIAL,
+	ENUMERATOR_OPENED,
+} eEnumeratorChannelState;
+
+typedef struct
+{
+	CamDevEnumServerContext context;
+
+	HANDLE stopEvent;
+
+	HANDLE thread;
+	void* enumerator_channel;
+
+	DWORD SessionId;
+
+	BOOL isOpened;
+	BOOL externalThread;
+
+	/* Channel state */
+	eEnumeratorChannelState state;
+
+	wStream* buffer;
+} enumerator_server;
+
+static UINT enumerator_server_initialize(CamDevEnumServerContext* context, BOOL externalThread)
+{
+	UINT error = CHANNEL_RC_OK;
+	enumerator_server* enumerator = (enumerator_server*)context;
+
+	WINPR_ASSERT(enumerator);
+
+	if (enumerator->isOpened)
+	{
+		WLog_WARN(TAG, "Application error: Camera Device Enumerator channel already initialized, "
+		               "calling in this state is not possible!");
+		return ERROR_INVALID_STATE;
+	}
+
+	enumerator->externalThread = externalThread;
+
+	return error;
+}
+
+static UINT enumerator_server_open_channel(enumerator_server* enumerator)
+{
+	CamDevEnumServerContext* context = &enumerator->context;
+	DWORD Error = ERROR_SUCCESS;
+	HANDLE hEvent = nullptr;
+	DWORD BytesReturned = 0;
+	PULONG pSessionId = nullptr;
+	UINT32 channelId = 0;
+	BOOL status = TRUE;
+
+	WINPR_ASSERT(enumerator);
+
+	if (WTSQuerySessionInformationA(enumerator->context.vcm, WTS_CURRENT_SESSION, WTSSessionId,
+	                                (LPSTR*)&pSessionId, &BytesReturned) == FALSE)
+	{
+		WLog_ERR(TAG, "WTSQuerySessionInformationA failed!");
+		return ERROR_INTERNAL_ERROR;
+	}
+
+	enumerator->SessionId = (DWORD)*pSessionId;
+	WTSFreeMemory(pSessionId);
+	hEvent = WTSVirtualChannelManagerGetEventHandle(enumerator->context.vcm);
+
+	if (WaitForSingleObject(hEvent, 1000) == WAIT_FAILED)
+	{
+		Error = GetLastError();
+		WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "!", Error);
+		return Error;
+	}
+
+	enumerator->enumerator_channel = WTSVirtualChannelOpenEx(
+	    enumerator->SessionId, RDPECAM_CONTROL_DVC_CHANNEL_NAME, WTS_CHANNEL_OPTION_DYNAMIC);
+	if (!enumerator->enumerator_channel)
+	{
+		Error = GetLastError();
+		WLog_ERR(TAG, "WTSVirtualChannelOpenEx failed with error %" PRIu32 "!", Error);
+		return Error;
+	}
+
+	channelId = WTSChannelGetIdByHandle(enumerator->enumerator_channel);
+
+	IFCALLRET(context->ChannelIdAssigned, status, context, channelId);
+	if (!status)
+	{
+		WLog_ERR(TAG, "context->ChannelIdAssigned failed!");
+		return ERROR_INTERNAL_ERROR;
+	}
+
+	return Error;
+}
+
+static UINT enumerator_server_handle_select_version_request(CamDevEnumServerContext* context,
+                                                            WINPR_ATTR_UNUSED wStream* s,
+                                                            const CAM_SHARED_MSG_HEADER* header)
+{
+	CAM_SELECT_VERSION_REQUEST pdu = WINPR_C_ARRAY_INIT;
+	UINT error = CHANNEL_RC_OK;
+
+	WINPR_ASSERT(context);
+	WINPR_ASSERT(header);
+
+	pdu.Header = *header;
+
+	IFCALLRET(context->SelectVersionRequest, error, context, &pdu);
+	if (error)
+		WLog_ERR(TAG, "context->SelectVersionRequest failed with error %" PRIu32 "", error);
+
+	return error;
+}
+
+static UINT enumerator_server_recv_device_added_notification(CamDevEnumServerContext* context,
+                                                             wStream* s,
+                                                             const CAM_SHARED_MSG_HEADER* header)
+{
+	CAM_DEVICE_ADDED_NOTIFICATION pdu;
+	UINT error = CHANNEL_RC_OK;
+	size_t remaining_length = 0;
+	WCHAR* channel_name_start = nullptr;
+
+	WINPR_ASSERT(context);
+	WINPR_ASSERT(header);
+
+	pdu.Header = *header;
+
+	/*
+	 * RequiredLength 4:
+	 *
+	 * Nullterminator DeviceName (2),
+	 * VirtualChannelName (>= 1),
+	 * Nullterminator VirtualChannelName (1)
+	 */
+	if (!Stream_CheckAndLogRequiredLength(TAG, s, 4))
+		return ERROR_NO_DATA;
+
+	pdu.DeviceName = Stream_Pointer(s);
+
+	remaining_length = Stream_GetRemainingLength(s);
+	channel_name_start = Stream_Pointer(s);
+
+	/* Search for null terminator of DeviceName */
+	size_t i = 0;
+	for (; i < remaining_length; i += sizeof(WCHAR), ++channel_name_start)
+	{
+		if (*channel_name_start == L'\0')
+			break;
+	}
+
+	if (*channel_name_start != L'\0')
+	{
+		WLog_ERR(TAG, "enumerator_server_recv_device_added_notification: Invalid DeviceName!");
+		return ERROR_INVALID_DATA;
+	}
+
+	pdu.VirtualChannelName = (char*)++channel_name_start;
+	++i;
+
+	if (i >= remaining_length || *pdu.VirtualChannelName == '\0')
+	{
+		WLog_ERR(TAG,
+		         "enumerator_server_recv_device_added_notification: Invalid VirtualChannelName!");
+		return ERROR_INVALID_DATA;
+	}
+
+	char* tmp = pdu.VirtualChannelName;
+	for (; i < remaining_length; ++i, ++tmp)
+	{
+		if (*tmp == '\0')
+			break;
+	}
+
+	if (*tmp != '\0')
+	{
+		WLog_ERR(TAG,
+		         "enumerator_server_recv_device_added_notification: Invalid VirtualChannelName!");
+		return ERROR_INVALID_DATA;
+	}
+
+	IFCALLRET(context->DeviceAddedNotification, error, context, &pdu);
+	if (error)
+		WLog_ERR(TAG, "context->DeviceAddedNotification failed with error %" PRIu32 "", error);
+
+	return error;
+}
+
+static UINT enumerator_server_recv_device_removed_notification(CamDevEnumServerContext* context,
+                                                               wStream* s,
+                                                               const CAM_SHARED_MSG_HEADER* header)
+{
+	CAM_DEVICE_REMOVED_NOTIFICATION pdu;
+	UINT error = CHANNEL_RC_OK;
+	size_t remaining_length = 0;
+
+	WINPR_ASSERT(context);
+	WINPR_ASSERT(header);
+
+	pdu.Header = *header;
+
+	if (!Stream_CheckAndLogRequiredLength(TAG, s, 2))
+		return ERROR_NO_DATA;
+
+	pdu.VirtualChannelName = Stream_Pointer(s);
+
+	remaining_length = Stream_GetRemainingLength(s);
+	char* tmp = pdu.VirtualChannelName + 1;
+
+	for (size_t i = 1; i < remaining_length; ++i, ++tmp)
+	{
+		if (*tmp == '\0')
+			break;
+	}
+
+	if (*tmp != '\0')
+	{
+		WLog_ERR(TAG,
+		         "enumerator_server_recv_device_removed_notification: Invalid VirtualChannelName!");
+		return ERROR_INVALID_DATA;
+	}
+
+	IFCALLRET(context->DeviceRemovedNotification, error, context, &pdu);
+	if (error)
+		WLog_ERR(TAG, "context->DeviceRemovedNotification failed with error %" PRIu32 "", error);
+
+	return error;
+}
+
+static UINT enumerator_process_message(enumerator_server* enumerator)
+{
+	BOOL rc = 0;
+	UINT error = ERROR_INTERNAL_ERROR;
+	ULONG BytesReturned = 0;
+	CAM_SHARED_MSG_HEADER header = WINPR_C_ARRAY_INIT;
+	wStream* s = nullptr;
+
+	WINPR_ASSERT(enumerator);
+	WINPR_ASSERT(enumerator->enumerator_channel);
+
+	s = enumerator->buffer;
+	WINPR_ASSERT(s);
+
+	Stream_ResetPosition(s);
+	rc = WTSVirtualChannelRead(enumerator->enumerator_channel, 0, nullptr, 0, &BytesReturned);
+	if (!rc)
+		goto out;
+
+	if (BytesReturned < 1)
+	{
+		error = CHANNEL_RC_OK;
+		goto out;
+	}
+
+	if (!Stream_EnsureRemainingCapacity(s, BytesReturned))
+	{
+		WLog_ERR(TAG, "Stream_EnsureRemainingCapacity failed!");
+		error = CHANNEL_RC_NO_MEMORY;
+		goto out;
+	}
+
+	if (WTSVirtualChannelRead(enumerator->enumerator_channel, 0, Stream_BufferAs(s, char),
+	                          (ULONG)Stream_Capacity(s), &BytesReturned) == FALSE)
+	{
+		WLog_ERR(TAG, "WTSVirtualChannelRead failed!");
+		goto out;
+	}
+
+	Stream_SetLength(s, BytesReturned);
+	if (!Stream_CheckAndLogRequiredLength(TAG, s, CAM_HEADER_SIZE))
+		return ERROR_NO_DATA;
+
+	Stream_Read_UINT8(s, header.Version);
+	{
+		const UINT8 id = Stream_Get_UINT8(s);
+		if (!rdpecam_valid_messageId(id))
+			return ERROR_INVALID_DATA;
+		header.MessageId = (CAM_MSG_ID)id;
+	}
+
+	switch (header.MessageId)
+	{
+		case CAM_MSG_ID_SelectVersionRequest:
+			error =
+			    enumerator_server_handle_select_version_request(&enumerator->context, s, &header);
+			break;
+		case CAM_MSG_ID_DeviceAddedNotification:
+			error =
+			    enumerator_server_recv_device_added_notification(&enumerator->context, s, &header);
+			break;
+		case CAM_MSG_ID_DeviceRemovedNotification:
+			error = enumerator_server_recv_device_removed_notification(&enumerator->context, s,
+			                                                           &header);
+			break;
+		default:
+			WLog_ERR(TAG, "enumerator_process_message: unknown or invalid MessageId %" PRIu8 "",
+			         header.MessageId);
+			break;
+	}
+
+out:
+	if (error)
+		WLog_ERR(TAG, "Response failed with error %" PRIu32 "!", error);
+
+	return error;
+}
+
+static UINT enumerator_server_context_poll_int(CamDevEnumServerContext* context)
+{
+	enumerator_server* enumerator = (enumerator_server*)context;
+	UINT error = ERROR_INTERNAL_ERROR;
+
+	WINPR_ASSERT(enumerator);
+
+	switch (enumerator->state)
+	{
+		case ENUMERATOR_INITIAL:
+			error = enumerator_server_open_channel(enumerator);
+			if (error)
+				WLog_ERR(TAG, "enumerator_server_open_channel failed with error %" PRIu32 "!",
+				         error);
+			else
+				enumerator->state = ENUMERATOR_OPENED;
+			break;
+		case ENUMERATOR_OPENED:
+			error = enumerator_process_message(enumerator);
+			break;
+		default:
+			break;
+	}
+
+	return error;
+}
+
+static HANDLE enumerator_server_get_channel_handle(enumerator_server* enumerator)
+{
+	void* buffer = nullptr;
+	DWORD BytesReturned = 0;
+	HANDLE ChannelEvent = nullptr;
+
+	WINPR_ASSERT(enumerator);
+
+	if (WTSVirtualChannelQuery(enumerator->enumerator_channel, WTSVirtualEventHandle, &buffer,
+	                           &BytesReturned) == TRUE)
+	{
+		if (BytesReturned == sizeof(HANDLE))
+			ChannelEvent = *(HANDLE*)buffer;
+
+		WTSFreeMemory(buffer);
+	}
+
+	return ChannelEvent;
+}
+
+static DWORD WINAPI enumerator_server_thread_func(LPVOID arg)
+{
+	DWORD nCount = 0;
+	HANDLE events[2] = WINPR_C_ARRAY_INIT;
+	enumerator_server* enumerator = (enumerator_server*)arg;
+	UINT error = CHANNEL_RC_OK;
+	DWORD status = 0;
+
+	WINPR_ASSERT(enumerator);
+
+	nCount = 0;
+	events[nCount++] = enumerator->stopEvent;
+
+	while ((error == CHANNEL_RC_OK) && (WaitForSingleObject(events[0], 0) != WAIT_OBJECT_0))
+	{
+		switch (enumerator->state)
+		{
+			case ENUMERATOR_INITIAL:
+				error = enumerator_server_context_poll_int(&enumerator->context);
+				if (error == CHANNEL_RC_OK)
+				{
+					events[1] = enumerator_server_get_channel_handle(enumerator);
+					nCount = 2;
+				}
+				break;
+			case ENUMERATOR_OPENED:
+				status = WaitForMultipleObjects(nCount, events, FALSE, INFINITE);
+				switch (status)
+				{
+					case WAIT_OBJECT_0:
+						break;
+					case WAIT_OBJECT_0 + 1:
+					case WAIT_TIMEOUT:
+						error = enumerator_server_context_poll_int(&enumerator->context);
+						break;
+
+					case WAIT_FAILED:
+					default:
+						error = ERROR_INTERNAL_ERROR;
+						break;
+				}
+				break;
+			default:
+				break;
+		}
+	}
+
+	(void)WTSVirtualChannelClose(enumerator->enumerator_channel);
+	enumerator->enumerator_channel = nullptr;
+
+	if (error && enumerator->context.rdpcontext)
+		setChannelError(enumerator->context.rdpcontext, error,
+		                "enumerator_server_thread_func reported an error");
+
+	ExitThread(error);
+	return error;
+}
+
+static UINT enumerator_server_open(CamDevEnumServerContext* context)
+{
+	enumerator_server* enumerator = (enumerator_server*)context;
+
+	WINPR_ASSERT(enumerator);
+
+	if (!enumerator->externalThread && (enumerator->thread == nullptr))
+	{
+		enumerator->stopEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr);
+		if (!enumerator->stopEvent)
+		{
+			WLog_ERR(TAG, "CreateEvent failed!");
+			return ERROR_INTERNAL_ERROR;
+		}
+
+		enumerator->thread =
+		    CreateThread(nullptr, 0, enumerator_server_thread_func, enumerator, 0, nullptr);
+		if (!enumerator->thread)
+		{
+			WLog_ERR(TAG, "CreateThread failed!");
+			(void)CloseHandle(enumerator->stopEvent);
+			enumerator->stopEvent = nullptr;
+			return ERROR_INTERNAL_ERROR;
+		}
+	}
+	enumerator->isOpened = TRUE;
+
+	return CHANNEL_RC_OK;
+}
+
+static UINT enumerator_server_close(CamDevEnumServerContext* context)
+{
+	UINT error = CHANNEL_RC_OK;
+	enumerator_server* enumerator = (enumerator_server*)context;
+
+	WINPR_ASSERT(enumerator);
+
+	if (!enumerator->externalThread && enumerator->thread)
+	{
+		(void)SetEvent(enumerator->stopEvent);
+
+		if (WaitForSingleObject(enumerator->thread, INFINITE) == WAIT_FAILED)
+		{
+			error = GetLastError();
+			WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "", error);
+			return error;
+		}
+
+		(void)CloseHandle(enumerator->thread);
+		(void)CloseHandle(enumerator->stopEvent);
+		enumerator->thread = nullptr;
+		enumerator->stopEvent = nullptr;
+	}
+	if (enumerator->externalThread)
+	{
+		if (enumerator->state != ENUMERATOR_INITIAL)
+		{
+			(void)WTSVirtualChannelClose(enumerator->enumerator_channel);
+			enumerator->enumerator_channel = nullptr;
+			enumerator->state = ENUMERATOR_INITIAL;
+		}
+	}
+	enumerator->isOpened = FALSE;
+
+	return error;
+}
+
+static UINT enumerator_server_context_poll(CamDevEnumServerContext* context)
+{
+	enumerator_server* enumerator = (enumerator_server*)context;
+
+	WINPR_ASSERT(enumerator);
+
+	if (!enumerator->externalThread)
+		return ERROR_INTERNAL_ERROR;
+
+	return enumerator_server_context_poll_int(context);
+}
+
+static BOOL enumerator_server_context_handle(CamDevEnumServerContext* context, HANDLE* handle)
+{
+	enumerator_server* enumerator = (enumerator_server*)context;
+
+	WINPR_ASSERT(enumerator);
+	WINPR_ASSERT(handle);
+
+	if (!enumerator->externalThread)
+		return FALSE;
+	if (enumerator->state == ENUMERATOR_INITIAL)
+		return FALSE;
+
+	*handle = enumerator_server_get_channel_handle(enumerator);
+
+	return TRUE;
+}
+
+static UINT enumerator_server_packet_send(CamDevEnumServerContext* context, wStream* s)
+{
+	enumerator_server* enumerator = (enumerator_server*)context;
+	UINT error = CHANNEL_RC_OK;
+	ULONG written = 0;
+
+	const size_t len = Stream_GetPosition(s);
+	WINPR_ASSERT(len <= UINT32_MAX);
+	if (!WTSVirtualChannelWrite(enumerator->enumerator_channel, Stream_BufferAs(s, char),
+	                            (UINT32)len, &written))
+	{
+		WLog_ERR(TAG, "WTSVirtualChannelWrite failed!");
+		error = ERROR_INTERNAL_ERROR;
+		goto out;
+	}
+
+	if (written < Stream_GetPosition(s))
+	{
+		WLog_WARN(TAG, "Unexpected bytes written: %" PRIu32 "/%" PRIuz "", written,
+		          Stream_GetPosition(s));
+	}
+
+out:
+	Stream_Free(s, TRUE);
+	return error;
+}
+
+static UINT enumerator_send_select_version_response_pdu(
+    CamDevEnumServerContext* context, const CAM_SELECT_VERSION_RESPONSE* selectVersionResponse)
+{
+	wStream* s = nullptr;
+
+	s = Stream_New(nullptr, CAM_HEADER_SIZE);
+	if (!s)
+	{
+		WLog_ERR(TAG, "Stream_New failed!");
+		return ERROR_NOT_ENOUGH_MEMORY;
+	}
+
+	Stream_Write_UINT8(s, selectVersionResponse->Header.Version);
+	Stream_Write_UINT8(s,
+	                   WINPR_ASSERTING_INT_CAST(uint8_t, selectVersionResponse->Header.MessageId));
+
+	return enumerator_server_packet_send(context, s);
+}
+
+CamDevEnumServerContext* cam_dev_enum_server_context_new(HANDLE vcm)
+{
+	enumerator_server* enumerator = (enumerator_server*)calloc(1, sizeof(enumerator_server));
+
+	if (!enumerator)
+		return nullptr;
+
+	enumerator->context.vcm = vcm;
+	enumerator->context.Initialize = enumerator_server_initialize;
+	enumerator->context.Open = enumerator_server_open;
+	enumerator->context.Close = enumerator_server_close;
+	enumerator->context.Poll = enumerator_server_context_poll;
+	enumerator->context.ChannelHandle = enumerator_server_context_handle;
+
+	enumerator->context.SelectVersionResponse = enumerator_send_select_version_response_pdu;
+
+	enumerator->buffer = Stream_New(nullptr, 4096);
+	if (!enumerator->buffer)
+		goto fail;
+
+	return &enumerator->context;
+fail:
+	WINPR_PRAGMA_DIAG_PUSH
+	WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC
+	cam_dev_enum_server_context_free(&enumerator->context);
+	WINPR_PRAGMA_DIAG_POP
+	return nullptr;
+}
+
+void cam_dev_enum_server_context_free(CamDevEnumServerContext* context)
+{
+	enumerator_server* enumerator = (enumerator_server*)context;
+
+	if (enumerator)
+	{
+		enumerator_server_close(context);
+		Stream_Free(enumerator->buffer, TRUE);
+	}
+
+	free(enumerator);
+}