mike-jumper commented on a change in pull request #243: GUACAMOLE-249: Migrate to FreeRDP 2.x URL: https://github.com/apache/guacamole-server/pull/243#discussion_r365556483
########## File path: src/protocols/rdp/channels/cliprdr.c ########## @@ -0,0 +1,601 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 "channels/cliprdr.h" +#include "client.h" +#include "common/clipboard.h" +#include "common/iconv.h" +#include "plugins/channels.h" +#include "rdp.h" + +#include <freerdp/client/cliprdr.h> +#include <freerdp/event.h> +#include <freerdp/freerdp.h> +#include <guacamole/client.h> +#include <guacamole/stream.h> +#include <guacamole/user.h> +#include <winpr/wtsapi.h> +#include <winpr/wtypes.h> + +#include <assert.h> +#include <stdlib.h> +#include <string.h> + +/** + * Sends a Format List PDU to the RDP server containing the formats of + * clipboard data supported. This PDU is used both to indicate the general + * clipboard formats supported at the begining of an RDP session and to inform + * the RDP server that new clipboard data is available within the listed + * formats. + * + * @param cliprdr + * The CliprdrClientContext structure used by FreeRDP to handle the + * CLIPRDR channel for the current RDP session. + * + * @return + * CHANNEL_RC_OK (zero) if the Format List PDU was sent successfully, an + * error code (non-zero) otherwise. + */ +static UINT guac_rdp_cliprdr_send_format_list(CliprdrClientContext* cliprdr) { + + /* This function is only invoked within FreeRDP-specific handlers for + * CLIPRDR, which are not assigned, and thus not callable, until after the + * relevant guac_rdp_clipboard structure is allocated and associated with + * the CliprdrClientContext */ + guac_rdp_clipboard* clipboard = (guac_rdp_clipboard*) cliprdr->custom; + assert(clipboard != NULL); + + /* We support CP-1252 and UTF-16 text */ + CLIPRDR_FORMAT_LIST format_list = { + .formats = (CLIPRDR_FORMAT[]) { + { .formatId = CF_TEXT }, + { .formatId = CF_UNICODETEXT } + }, + .numFormats = 2 + }; + + guac_client_log(clipboard->client, GUAC_LOG_TRACE, "CLIPRDR: Sending " + "format list"); + + return cliprdr->ClientFormatList(cliprdr, &format_list); + +} + +/** + * Sends a Clipboard Capabilities PDU to the RDP server describing the features + * of the CLIPRDR channel that are supported by the client. + * + * @param cliprdr + * The CliprdrClientContext structure used by FreeRDP to handle the + * CLIPRDR channel for the current RDP session. + * + * @return + * CHANNEL_RC_OK (zero) if the Clipboard Capabilities PDU was sent + * successfully, an error code (non-zero) otherwise. + */ +static UINT guac_rdp_cliprdr_send_capabilities(CliprdrClientContext* cliprdr) { + + CLIPRDR_GENERAL_CAPABILITY_SET cap_set = { + .capabilitySetType = CB_CAPSTYPE_GENERAL, /* CLIPRDR specification requires that this is CB_CAPSTYPE_GENERAL, the only defined set type */ + .capabilitySetLength = 12, /* The size of the capability set within the PDU - for CB_CAPSTYPE_GENERAL, this is ALWAYS 12 bytes */ + .version = CB_CAPS_VERSION_2, /* The version of the CLIPRDR specification supported */ + .generalFlags = CB_USE_LONG_FORMAT_NAMES /* Bitwise OR of all supported feature flags */ + }; + + CLIPRDR_CAPABILITIES caps = { + .cCapabilitiesSets = 1, + .capabilitySets = (CLIPRDR_CAPABILITY_SET*) &cap_set + }; + + return cliprdr->ClientCapabilities(cliprdr, &caps); + +} + +/** + * Callback invoked by the FreeRDP CLIPRDR plugin for received Monitor Ready + * PDUs. The Monitor Ready PDU is sent by the RDP server only during + * initialization of the CLIPRDR channel. It is part of the CLIPRDR channel + * handshake and indicates that the RDP server's handling of clipboard + * redirection is ready to proceed. + * + * @param cliprdr + * The CliprdrClientContext structure used by FreeRDP to handle the CLIPRDR + * channel for the current RDP session. + * + * @param monitor_ready + * The CLIPRDR_MONITOR_READY structure representing the Monitor Ready PDU + * that was received. + * + * @return + * CHANNEL_RC_OK (zero) if the PDU was handled successfully, an error code + * (non-zero) otherwise. + */ +static UINT guac_rdp_cliprdr_monitor_ready(CliprdrClientContext* cliprdr, + const CLIPRDR_MONITOR_READY* monitor_ready) { + + /* FreeRDP-specific handlers for CLIPRDR are not assigned, and thus not + * callable, until after the relevant guac_rdp_clipboard structure is + * allocated and associated with the CliprdrClientContext */ + guac_rdp_clipboard* clipboard = (guac_rdp_clipboard*) cliprdr->custom; + assert(clipboard != NULL); + + guac_client_log(clipboard->client, GUAC_LOG_TRACE, "CLIPRDR: Received " + "monitor ready."); + + /* Respond with capabilities and supported format list */ + guac_rdp_cliprdr_send_capabilities(cliprdr); + return guac_rdp_cliprdr_send_format_list(cliprdr); + +} + +/** + * Sends a Format Data Request PDU to the RDP server, requesting that available + * clipboard data be sent to the client in the specified format. This PDU is + * sent when the server indicating that clipboard data is available via a + * Format List PDU. + * + * @param client + * The guac_client associated with the current RDP session. + * + * @param format + * The clipboard format to request. This format must be one of the + * documented values used by the CLIPRDR channel for clipboard format IDs. + * + * @return + * CHANNEL_RC_OK (zero) if the PDU was handled successfully, an error code + * (non-zero) otherwise. + */ +static UINT guac_rdp_cliprdr_send_format_data_request( + CliprdrClientContext* cliprdr, UINT32 format) { + + /* FreeRDP-specific handlers for CLIPRDR are not assigned, and thus not + * callable, until after the relevant guac_rdp_clipboard structure is + * allocated and associated with the CliprdrClientContext */ + guac_rdp_clipboard* clipboard = (guac_rdp_clipboard*) cliprdr->custom; + assert(clipboard != NULL); + + /* Create new data request */ + CLIPRDR_FORMAT_DATA_REQUEST data_request = { + .requestedFormatId = format + }; + + /* Note the format we've requested for reference later when the requested + * data is received via a Format Data Response PDU */ + clipboard->requested_format = format; + + guac_client_log(clipboard->client, GUAC_LOG_TRACE, "CLIPRDR: Sending " + "format data request."); + + /* Send request */ + return cliprdr->ClientFormatDataRequest(cliprdr, &data_request); + +} + +/** + * Returns whether the given Format List PDU indicates support for the given + * clipboard format. + * + * @param format_list + * The CLIPRDR_FORMAT_LIST structure representing the Format List PDU + * being tested. + * + * @param format_id + * The ID of the clipboard format to test, such as CF_TEXT or + * CF_UNICODETEXT. + * + * @return + * Non-zero if the given Format List PDU indicates support for the given + * clipboard format, zero otherwise. + */ +static int guac_rdp_cliprdr_format_supported(const CLIPRDR_FORMAT_LIST* format_list, + UINT format_id) { + + /* Search format list for matching ID */ + for (int i = 0; i < format_list->numFormats; i++) { + if (format_list->formats[i].formatId == format_id) + return 1; + } + + /* If no matching ID, format is not supported */ + return 0; + +} + +/** + * Callback invoked by the FreeRDP CLIPRDR plugin for received Format List + * PDUs. The Format List PDU is sent by the RDP server to indicate that new + * clipboard data has been copied and is available for retrieval in the formats + * listed. A client wishing to retrieve that data responds with a Format Data + * Request PDU. + * + * @param cliprdr + * The CliprdrClientContext structure used by FreeRDP to handle the CLIPRDR + * channel for the current RDP session. + * + * @param format_list + * The CLIPRDR_FORMAT_LIST structure representing the Format List PDU that + * was received. + * + * @return + * CHANNEL_RC_OK (zero) if the PDU was handled successfully, an error code + * (non-zero) otherwise. + */ +static UINT guac_rdp_cliprdr_format_list(CliprdrClientContext* cliprdr, + const CLIPRDR_FORMAT_LIST* format_list) { + + /* FreeRDP-specific handlers for CLIPRDR are not assigned, and thus not + * callable, until after the relevant guac_rdp_clipboard structure is + * allocated and associated with the CliprdrClientContext */ + guac_rdp_clipboard* clipboard = (guac_rdp_clipboard*) cliprdr->custom; + assert(clipboard != NULL); + + guac_client_log(clipboard->client, GUAC_LOG_TRACE, "CLIPRDR: Received " + "format list."); + + CLIPRDR_FORMAT_LIST_RESPONSE format_list_response = { + .msgFlags = CB_RESPONSE_OK + }; + + /* Report successful processing of format list */ + cliprdr->ClientFormatListResponse(cliprdr, &format_list_response); + + /* Prefer Unicode (in this case, UTF-16) */ + if (guac_rdp_cliprdr_format_supported(format_list, CF_UNICODETEXT)) + return guac_rdp_cliprdr_send_format_data_request(cliprdr, CF_UNICODETEXT); + + /* Use Windows' CP-1252 if Unicode unavailable */ + if (guac_rdp_cliprdr_format_supported(format_list, CF_TEXT)) + return guac_rdp_cliprdr_send_format_data_request(cliprdr, CF_TEXT); + + /* Ignore any unsupported data */ + guac_client_log(clipboard->client, GUAC_LOG_DEBUG, "Ignoring unsupported " + "clipboard data. Only Unicode and text clipboard formats are " + "currently supported."); + + return CHANNEL_RC_OK; + +} + +/** + * Callback invoked by the FreeRDP CLIPRDR plugin for received Format Data + * Request PDUs. The Format Data Request PDU is sent by the RDP server when + * requesting that clipboard data be sent, in response to a received Format + * List PDU. The client is required to respond with a Format Data Response PDU + * containing the requested data. + * + * @param cliprdr + * The CliprdrClientContext structure used by FreeRDP to handle the CLIPRDR + * channel for the current RDP session. + * + * @param format_data_request + * The CLIPRDR_FORMAT_DATA_REQUEST structure representing the Format Data + * Request PDU that was received. + * + * @return + * CHANNEL_RC_OK (zero) if the PDU was handled successfully, an error code + * (non-zero) otherwise. + */ +static UINT guac_rdp_cliprdr_format_data_request(CliprdrClientContext* cliprdr, + const CLIPRDR_FORMAT_DATA_REQUEST* format_data_request) { + + /* FreeRDP-specific handlers for CLIPRDR are not assigned, and thus not + * callable, until after the relevant guac_rdp_clipboard structure is + * allocated and associated with the CliprdrClientContext */ + guac_rdp_clipboard* clipboard = (guac_rdp_clipboard*) cliprdr->custom; + assert(clipboard != NULL); + + guac_client_log(clipboard->client, GUAC_LOG_TRACE, "CLIPRDR: Received " + "format data request."); + + guac_iconv_write* writer; + const char* input = clipboard->clipboard->buffer; + char* output = malloc(GUAC_RDP_CLIPBOARD_MAX_LENGTH); + + /* Map requested clipboard format to a guac_iconv writer */ + switch (format_data_request->requestedFormatId) { + + case CF_TEXT: + writer = GUAC_WRITE_CP1252; + break; + + case CF_UNICODETEXT: + writer = GUAC_WRITE_UTF16; + break; + + /* Warn if clipboard data cannot be sent as intended due to a violation + * of the CLIPRDR spec */ + default: + guac_client_log(clipboard->client, GUAC_LOG_WARNING, "Received " + "clipboard data cannot be sent to the RDP server because " + "the RDP server has requested a clipboard format which " + "was not declared as available. This violates the " + "specification for the CLIPRDR channel."); + free(output); + return CHANNEL_RC_OK; + + } + + /* Send received clipboard data to the RDP server in the format + * requested */ + BYTE* start = (BYTE*) output; + guac_iconv(GUAC_READ_UTF8, &input, clipboard->clipboard->length, + writer, &output, GUAC_RDP_CLIPBOARD_MAX_LENGTH); + + CLIPRDR_FORMAT_DATA_RESPONSE data_response = { + .requestedFormatData = (BYTE*) start, + .dataLen = ((BYTE*) output) - start, + .msgFlags = CB_RESPONSE_OK + }; + + guac_client_log(clipboard->client, GUAC_LOG_TRACE, "CLIPRDR: Sending " + "format data response."); + + return cliprdr->ClientFormatDataResponse(cliprdr, &data_response); + +} + +/** + * Callback invoked by the FreeRDP CLIPRDR plugin for received Format Data + * Response PDUs. The Format Data Response PDU is sent by the RDP server when + * fullfilling a request for clipboard data received via a Format Data Request + * PDU. + * + * @param cliprdr + * The CliprdrClientContext structure used by FreeRDP to handle the CLIPRDR + * channel for the current RDP session. + * + * @param format_data_response + * The CLIPRDR_FORMAT_DATA_RESPONSE structure representing the Format Data + * Response PDU that was received. + * + * @return + * CHANNEL_RC_OK (zero) if the PDU was handled successfully, an error code + * (non-zero) otherwise. + */ +static UINT guac_rdp_cliprdr_format_data_response(CliprdrClientContext* cliprdr, + const CLIPRDR_FORMAT_DATA_RESPONSE* format_data_response) { + + /* FreeRDP-specific handlers for CLIPRDR are not assigned, and thus not + * callable, until after the relevant guac_rdp_clipboard structure is + * allocated and associated with the CliprdrClientContext */ + guac_rdp_clipboard* clipboard = (guac_rdp_clipboard*) cliprdr->custom; + assert(clipboard != NULL); + + guac_client_log(clipboard->client, GUAC_LOG_TRACE, "CLIPRDR: Received " + "format data response."); + + char received_data[GUAC_RDP_CLIPBOARD_MAX_LENGTH]; + + guac_iconv_read* reader; + const char* input = (char*) format_data_response->requestedFormatData; + char* output = received_data; + + /* Find correct source encoding */ + switch (clipboard->requested_format) { + + /* Non-Unicode (Windows CP-1252) */ + case CF_TEXT: + reader = GUAC_READ_CP1252; + break; + + /* Unicode (UTF-16) */ + case CF_UNICODETEXT: + reader = GUAC_READ_UTF16; + break; + + /* If the format ID stored within the guac_rdp_clipboard structure is actually + * not supported here, then something has been implemented incorrectly. + * Either incorrect values are (somehow) being stored, or support for + * the format indicated by that value is incomplete and must be added + * here. The values which may be stored within requested_format are + * completely within our control. */ Review comment: I believe so (see my other response regarding FreeRDP's CLIPRDR thread and its error handling). ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
