FreeRDP/server/proxy/pf_cliprdr.c

/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * FreeRDP Proxy Server
 *
 * Copyright 2019 Kobi Mizrachi <kmizrachi18@gmail.com>
 * Copyright 2019 Idan Freiberg <speidy@gmail.com>
 *
 * 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 "pf_cliprdr.h"
#include "pf_log.h"

#define TAG PROXY_TAG("cliprdr")
#define TEXT_FORMATS_COUNT 2

/* used for createing a fake format list response, containing only text formats */
static CLIPRDR_FORMAT g_text_formats[] = { { CF_TEXT, '\0' }, { CF_UNICODETEXT, '\0' } };

BOOL pf_server_cliprdr_init(pServerContext* ps)
{
	CliprdrServerContext* cliprdr;
	cliprdr = ps->cliprdr = cliprdr_server_context_new(ps->vcm);

	if (!cliprdr)
	{
		WLog_ERR(TAG, "cliprdr_server_context_new failed.");
		return FALSE;
	}

	cliprdr->rdpcontext = (rdpContext*)ps;

	/* enable all capabilities */
	cliprdr->useLongFormatNames = TRUE;
	cliprdr->streamFileClipEnabled = TRUE;
	cliprdr->fileClipNoFilePaths = TRUE;
	cliprdr->canLockClipData = TRUE;

	/* disable initialization sequence, for caps sync */
	cliprdr->autoInitializationSequence = FALSE;
	return TRUE;
}

static INLINE BOOL pf_cliprdr_is_text_format(UINT32 format)
{
	switch (format)
	{
		case CF_TEXT:
		case CF_UNICODETEXT:
			return TRUE;
	}

	return FALSE;
}

static INLINE void pf_cliprdr_create_text_only_format_list(CLIPRDR_FORMAT_LIST* list)
{
	list->msgFlags = CB_RESPONSE_OK;
	list->msgType = CB_FORMAT_LIST;
	list->dataLen = (4 + 1) * TEXT_FORMATS_COUNT;
	list->numFormats = TEXT_FORMATS_COUNT;
	list->formats = g_text_formats;
}

/* format data response PDU returns the copied text as a unicode buffer.
 * pf_cliprdr_is_copy_paste_valid returns TRUE if the length of the copied
 * text is valid according to the configuration value of `MaxTextLength`.
 */
static BOOL pf_cliprdr_is_copy_paste_valid(proxyConfig* config,
        const CLIPRDR_FORMAT_DATA_RESPONSE* pdu, UINT32 format)
{
	size_t copy_len;
	if (config->MaxTextLength == 0)
	{
		/* no size limit */
		return TRUE;
	}

	if (pdu->dataLen == 0)
	{
		/* no data */
		return FALSE;
	}

	WLog_DBG(TAG, "pf_cliprdr_is_copy_paste_valid(): checking format %"PRIu32"", format);

	switch (format)
	{
		case CF_UNICODETEXT:
			copy_len = (pdu->dataLen / 2) - 1;
			break;
		case CF_TEXT:
			copy_len = pdu->dataLen;
			break;
		default:
			WLog_WARN(TAG, "received unknown format: %"PRIu32", format");
			return FALSE;
	}

	if (copy_len > config->MaxTextLength)
	{
		WLog_WARN(TAG, "text size is too large: %"PRIu32" (max %"PRIu32")", copy_len,
		          config->MaxTextLength);
		return FALSE;
	}

	return TRUE;
}

/*
 * if the requested text size is too long, we need a way to return a message to the other side of
 * the connection, indicating that the copy/paste operation failed, instead of just not forwarding
 * the response (because that destroys the state of the RDPECLIP channel). This is done by sending a
 * `format_data_response` PDU with msgFlags = CB_RESPONSE_FAIL.
 */
static INLINE void pf_cliprdr_create_failed_format_data_response(CLIPRDR_FORMAT_DATA_RESPONSE* dst)
{
	dst->requestedFormatData = NULL;
	dst->dataLen = 0;
	dst->msgType = CB_FORMAT_DATA_RESPONSE;
	dst->msgFlags = CB_RESPONSE_FAIL;
}

/* server callbacks */
static UINT pf_cliprdr_ClientCapabilities(CliprdrServerContext* context,
        const CLIPRDR_CAPABILITIES* capabilities)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return client->ClientCapabilities(client, capabilities);
}

static UINT pf_cliprdr_TempDirectory(CliprdrServerContext* context,
                                     const CLIPRDR_TEMP_DIRECTORY* tempDirectory)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return client->TempDirectory(client, tempDirectory);
}

static UINT pf_cliprdr_ClientFormatList(CliprdrServerContext* context,
                                        const CLIPRDR_FORMAT_LIST* formatList)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly)
	{
		CLIPRDR_FORMAT_LIST list;
		pf_cliprdr_create_text_only_format_list(&list);
		return client->ClientFormatList(client, &list);
	}

	/* send a format list that allows only text */
	return client->ClientFormatList(client, formatList);
}

static UINT pf_cliprdr_ClientFormatListResponse(CliprdrServerContext* context,
        const CLIPRDR_FORMAT_LIST_RESPONSE* formatListResponse)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return client->ClientFormatListResponse(client, formatListResponse);
}

static UINT pf_cliprdr_ClientLockClipboardData(CliprdrServerContext* context,
        const CLIPRDR_LOCK_CLIPBOARD_DATA* lockClipboardData)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return client->ClientLockClipboardData(client, lockClipboardData);
}

static UINT pf_cliprdr_ClientUnlockClipboardData(CliprdrServerContext* context,
        const CLIPRDR_UNLOCK_CLIPBOARD_DATA* unlockClipboardData)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return client->ClientUnlockClipboardData(client, unlockClipboardData);
}

static UINT pf_cliprdr_ClientFormatDataRequest(CliprdrServerContext* context,
        const CLIPRDR_FORMAT_DATA_REQUEST* formatDataRequest)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly &&
	    !pf_cliprdr_is_text_format(formatDataRequest->requestedFormatId))
	{
		CLIPRDR_FORMAT_DATA_RESPONSE resp;
		pf_cliprdr_create_failed_format_data_response(&resp);
		return server->ServerFormatDataResponse(server, &resp);
	}

	return client->ClientFormatDataRequest(client, formatDataRequest);
}

static UINT pf_cliprdr_ClientFormatDataResponse(CliprdrServerContext* context,
        const CLIPRDR_FORMAT_DATA_RESPONSE* formatDataResponse)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pf_cliprdr_is_text_format(client->lastRequestedFormatId))
	{
		if (!pf_cliprdr_is_copy_paste_valid(pdata->config, formatDataResponse, client->lastRequestedFormatId))
		{
			CLIPRDR_FORMAT_DATA_RESPONSE resp;
			pf_cliprdr_create_failed_format_data_response(&resp);
			return client->ClientFormatDataResponse(client, &resp);
		}
	}

	return client->ClientFormatDataResponse(client, formatDataResponse);
}

static UINT pf_cliprdr_ClientFileContentsRequest(CliprdrServerContext* context,
        const CLIPRDR_FILE_CONTENTS_REQUEST* fileContentsRequest)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly)
		return CHANNEL_RC_OK;

	return client->ClientFileContentsRequest(client, fileContentsRequest);
}

static UINT pf_cliprdr_ClientFileContentsResponse(CliprdrServerContext* context,
        const CLIPRDR_FILE_CONTENTS_RESPONSE* fileContentsResponse)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly)
		return CHANNEL_RC_OK;

	return client->ClientFileContentsResponse(client, fileContentsResponse);
}

/* client callbacks */

static UINT pf_cliprdr_ServerCapabilities(CliprdrClientContext* context,
        const CLIPRDR_CAPABILITIES* capabilities)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return server->ServerCapabilities(server, capabilities);
}

static UINT pf_cliprdr_MonitorReady(CliprdrClientContext* context,
                                    const CLIPRDR_MONITOR_READY* monitorReady)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return server->MonitorReady(server, monitorReady);
}

static UINT pf_cliprdr_ServerFormatList(CliprdrClientContext* context,
                                        const CLIPRDR_FORMAT_LIST* formatList)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly)
	{
		CLIPRDR_FORMAT_LIST list;
		pf_cliprdr_create_text_only_format_list(&list);
		return server->ServerFormatList(server, &list);
	}

	return server->ServerFormatList(server, formatList);
}


static UINT pf_cliprdr_ServerFormatListResponse(CliprdrClientContext* context,
        const CLIPRDR_FORMAT_LIST_RESPONSE* formatListResponse)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return server->ServerFormatListResponse(server, formatListResponse);
}


static UINT pf_cliprdr_ServerLockClipboardData(CliprdrClientContext* context,
        const CLIPRDR_LOCK_CLIPBOARD_DATA* lockClipboardData)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return server->ServerLockClipboardData(server, lockClipboardData);
}


static UINT pf_cliprdr_ServerUnlockClipboardData(CliprdrClientContext* context,
        const CLIPRDR_UNLOCK_CLIPBOARD_DATA* unlockClipboardData)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);
	return server->ServerUnlockClipboardData(server, unlockClipboardData);
}


static UINT pf_cliprdr_ServerFormatDataRequest(CliprdrClientContext* context,
        const CLIPRDR_FORMAT_DATA_REQUEST* formatDataRequest)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	CliprdrClientContext* client = pdata->pc->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly &&
	    !pf_cliprdr_is_text_format(formatDataRequest->requestedFormatId))
	{
		/* proxy's client needs to return a failed response directly to the client */
		CLIPRDR_FORMAT_DATA_RESPONSE resp;
		pf_cliprdr_create_failed_format_data_response(&resp);
		return client->ClientFormatDataResponse(client, &resp);
	}

	return server->ServerFormatDataRequest(server, formatDataRequest);
}

static UINT pf_cliprdr_ServerFormatDataResponse(CliprdrClientContext* context,
        const CLIPRDR_FORMAT_DATA_RESPONSE* formatDataResponse)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pf_cliprdr_is_text_format(server->lastRequestedFormatId))
	{
		if (!pf_cliprdr_is_copy_paste_valid(pdata->config, formatDataResponse, server->lastRequestedFormatId))
		{
			CLIPRDR_FORMAT_DATA_RESPONSE resp;
			pf_cliprdr_create_failed_format_data_response(&resp);
			return server->ServerFormatDataResponse(server, &resp);
		}
	}

	return server->ServerFormatDataResponse(server, formatDataResponse);
}


static UINT pf_cliprdr_ServerFileContentsRequest(CliprdrClientContext* context,
        const CLIPRDR_FILE_CONTENTS_REQUEST* fileContentsRequest)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly)
		return CHANNEL_RC_OK;

	return server->ServerFileContentsRequest(server, fileContentsRequest);
}


static UINT pf_cliprdr_ServerFileContentsResponse(CliprdrClientContext* context,
        const CLIPRDR_FILE_CONTENTS_RESPONSE* fileContentsResponse)
{
	proxyData* pdata = (proxyData*) context->custom;
	CliprdrServerContext* server = pdata->ps->cliprdr;
	WLog_VRB(TAG, __FUNCTION__);

	if (pdata->config->TextOnly)
		return CHANNEL_RC_OK;

	return server->ServerFileContentsResponse(server, fileContentsResponse);
}

void pf_cliprdr_register_callbacks(CliprdrClientContext* cliprdr_client,
                                 CliprdrServerContext* cliprdr_server,
                                 proxyData* pdata)
{
	/* Set server and client side references to proxy data */
	cliprdr_server->custom = (void*) pdata;
	cliprdr_client->custom = (void*) pdata;
	/* Set server callbacks */
	cliprdr_server->ClientCapabilities = pf_cliprdr_ClientCapabilities;
	cliprdr_server->TempDirectory = pf_cliprdr_TempDirectory;
	cliprdr_server->ClientFormatList = pf_cliprdr_ClientFormatList;
	cliprdr_server->ClientFormatListResponse = pf_cliprdr_ClientFormatListResponse;
	cliprdr_server->ClientLockClipboardData = pf_cliprdr_ClientLockClipboardData;
	cliprdr_server->ClientUnlockClipboardData = pf_cliprdr_ClientUnlockClipboardData;
	cliprdr_server->ClientFormatDataRequest = pf_cliprdr_ClientFormatDataRequest;
	cliprdr_server->ClientFormatDataResponse = pf_cliprdr_ClientFormatDataResponse;
	cliprdr_server->ClientFileContentsRequest = pf_cliprdr_ClientFileContentsRequest;
	cliprdr_server->ClientFileContentsResponse = pf_cliprdr_ClientFileContentsResponse;
	/* Set client callbacks */
	cliprdr_client->ServerCapabilities = pf_cliprdr_ServerCapabilities;
	cliprdr_client->MonitorReady = pf_cliprdr_MonitorReady;
	cliprdr_client->ServerFormatList = pf_cliprdr_ServerFormatList;
	cliprdr_client->ServerFormatListResponse = pf_cliprdr_ServerFormatListResponse;
	cliprdr_client->ServerLockClipboardData = pf_cliprdr_ServerLockClipboardData;
	cliprdr_client->ServerUnlockClipboardData = pf_cliprdr_ServerUnlockClipboardData;
	cliprdr_client->ServerFormatDataRequest = pf_cliprdr_ServerFormatDataRequest;
	cliprdr_client->ServerFormatDataResponse = pf_cliprdr_ServerFormatDataResponse;
	cliprdr_client->ServerFileContentsRequest = pf_cliprdr_ServerFileContentsRequest;
	cliprdr_client->ServerFileContentsResponse = pf_cliprdr_ServerFileContentsResponse;
}