Commit message: Fixed oob read in cliprdr_read_format_list
CVE: CVE-2020-11085
CWE: CWE-125
Vulnerability description: In FreeRDP before 2.1.0, there is an out-of-bounds read in cliprdr_read_format_list. Clipboard format data read (by client or server) might read data out-of-bounds. This has been fixed in 2.1.0.

Project: FreeRDP
File: cliprdr_common.c

wStream* cliprdr_packet_lock_clipdata_new(const CLIPRDR_LOCK_CLIPBOARD_DATA* lockClipboardData)
{
	wStream* s;

	if (!lockClipboardData)
		return NULL;

	s = cliprdr_packet_new(CB_LOCK_CLIPDATA, 0, 4);

	if (!s)
		return NULL;

	cliprdr_write_lock_clipdata(s, lockClipboardData);
	return s;
}

Project: FreeRDP
File: cliprdr_common.c

wStream* cliprdr_packet_file_contents_request_new(const CLIPRDR_FILE_CONTENTS_REQUEST* request)
{
	wStream* s;

	if (!request)
		return NULL;

	s = cliprdr_packet_new(CB_FILECONTENTS_REQUEST, 0, 28);

	if (!s)
		return NULL;

	cliprdr_write_file_contents_request(s, request);
	return s;
}

Project: FreeRDP
File: cliprdr_common.c

static void cliprdr_write_lock_clipdata(wStream* s,
                                        const CLIPRDR_LOCK_CLIPBOARD_DATA* lockClipboardData)
{
	cliprdr_write_lock_unlock_clipdata(s, lockClipboardData->clipDataId);
}

Project: FreeRDP
File: cliprdr_common.c

static void cliprdr_write_file_contents_response(wStream* s,
                                                 const CLIPRDR_FILE_CONTENTS_RESPONSE* response)
{
	Stream_Write_UINT32(s, response->streamId); /* streamId (4 bytes) */
	Stream_Write(s, response->requestedData, response->cbRequested);
}

Project: FreeRDP
File: cliprdr_common.c

UINT cliprdr_read_format_data_request(wStream* s, CLIPRDR_FORMAT_DATA_REQUEST* request)
{
	if (Stream_GetRemainingLength(s) < 4)
	{
		WLog_ERR(TAG, "not enough data in stream!");
		return ERROR_INVALID_DATA;
	}

	Stream_Read_UINT32(s, request->requestedFormatId); /* requestedFormatId (4 bytes) */
	return CHANNEL_RC_OK;
}

Project: FreeRDP
File: cliprdr_common.c

UINT cliprdr_read_format_data_response(wStream* s, CLIPRDR_FORMAT_DATA_RESPONSE* response)
{
	response->requestedFormatData = NULL;

	if (Stream_GetRemainingLength(s) < response->dataLen)
	{
		WLog_ERR(TAG, "not enough data in stream!");
		return ERROR_INVALID_DATA;
	}

	if (response->dataLen)
		response->requestedFormatData = Stream_Pointer(s);

	return CHANNEL_RC_OK;
}

Project: FreeRDP
File: cliprdr_common.c

wStream* cliprdr_packet_new(UINT16 msgType, UINT16 msgFlags, UINT32 dataLen)
{
	wStream* s;
	s = Stream_New(NULL, dataLen + 8);

	if (!s)
	{
		WLog_ERR(TAG, "Stream_New failed!");
		return NULL;
	}

	Stream_Write_UINT16(s, msgType);
	Stream_Write_UINT16(s, msgFlags);
	/* Write actual length after the entire packet has been constructed. */
	Stream_Seek(s, 4);
	return s;
}

Project: FreeRDP
File: cliprdr_common.c

static void cliprdr_write_file_contents_request(wStream* s,
                                                const CLIPRDR_FILE_CONTENTS_REQUEST* request)
{
	Stream_Write_UINT32(s, request->streamId);      /* streamId (4 bytes) */
	Stream_Write_UINT32(s, request->listIndex);     /* listIndex (4 bytes) */
	Stream_Write_UINT32(s, request->dwFlags);       /* dwFlags (4 bytes) */
	Stream_Write_UINT32(s, request->nPositionLow);  /* nPositionLow (4 bytes) */
	Stream_Write_UINT32(s, request->nPositionHigh); /* nPositionHigh (4 bytes) */
	Stream_Write_UINT32(s, request->cbRequested);   /* cbRequested (4 bytes) */

	if (request->haveClipDataId)
		Stream_Write_UINT32(s, request->clipDataId); /* clipDataId (4 bytes) */
}

Project: FreeRDP
File: cliprdr_common.c

static BOOL cliprdr_validate_file_contents_request(const CLIPRDR_FILE_CONTENTS_REQUEST* request)
{
	/*
	 * [MS-RDPECLIP] 2.2.5.3 File Contents Request PDU (CLIPRDR_FILECONTENTS_REQUEST).
	 *
	 * A request for the size of the file identified by the lindex field. The size MUST be
	 * returned as a 64-bit, unsigned integer. The cbRequested field MUST be set to
	 * 0x00000008 and both the nPositionLow and nPositionHigh fields MUST be
	 * set to 0x00000000.
	 */

	if (request->dwFlags & FILECONTENTS_SIZE)
	{
		if (request->cbRequested != sizeof(UINT64))
		{
			WLog_ERR(TAG, "[%s]: cbRequested must be %" PRIu32 ", got %" PRIu32 "", __FUNCTION__,
			         sizeof(UINT64), request->cbRequested);
			return FALSE;
		}

		if (request->nPositionHigh != 0 || request->nPositionLow != 0)
		{
			WLog_ERR(TAG, "[%s]: nPositionHigh and nPositionLow must be set to 0", __FUNCTION__);
			return FALSE;
		}
	}

	return TRUE;
}

Project: FreeRDP
File: cliprdr_common.c

static INLINE void cliprdr_write_lock_unlock_clipdata(wStream* s, UINT32 clipDataId)
{
	Stream_Write_UINT32(s, clipDataId);
}

Project: FreeRDP
File: cliprdr_common.c

static void cliprdr_write_unlock_clipdata(wStream* s,
                                          const CLIPRDR_UNLOCK_CLIPBOARD_DATA* unlockClipboardData)
{
	cliprdr_write_lock_unlock_clipdata(s, unlockClipboardData->clipDataId);
}

Project: FreeRDP
File: cliprdr_common.c

void cliprdr_free_format_list(CLIPRDR_FORMAT_LIST* formatList)
{
	UINT index = 0;

	if (formatList == NULL)
		return;

	if (formatList->formats)
	{
		for (index = 0; index < formatList->numFormats; index++)
		{
			free(formatList->formats[index].formatName);
		}

		free(formatList->formats);
		formatList->formats = NULL;
		formatList->numFormats = 0;
	}
}

Project: FreeRDP
File: cliprdr_common.c

cliprdr_packet_unlock_clipdata_new(const CLIPRDR_UNLOCK_CLIPBOARD_DATA* unlockClipboardData)
{
	wStream* s;

	if (!unlockClipboardData)
		return NULL;

	s = cliprdr_packet_new(CB_LOCK_CLIPDATA, 0, 4);

	if (!s)
		return NULL;

	cliprdr_write_unlock_clipdata(s, unlockClipboardData);
	return s;
}

Project: FreeRDP
File: cliprdr_common.c

UINT cliprdr_read_format_list(wStream* s, CLIPRDR_FORMAT_LIST* formatList, BOOL useLongFormatNames)
{
	UINT32 index;
	size_t position;
	BOOL asciiNames;
	int formatNameLength;
	char* szFormatName;
	WCHAR* wszFormatName;
	wStream sub1, sub2;
	CLIPRDR_FORMAT* formats = NULL;
	UINT error = CHANNEL_RC_OK;

	asciiNames = (formatList->msgFlags & CB_ASCII_NAMES) ? TRUE : FALSE;

	index = 0;
	/* empty format list */
	formatList->formats = NULL;
	formatList->numFormats = 0;

	Stream_StaticInit(&sub1, Stream_Pointer(s), formatList->dataLen);
	if (!Stream_SafeSeek(s, formatList->dataLen))
		return ERROR_INVALID_DATA;

	if (!formatList->dataLen)
	{
	}
	else if (!useLongFormatNames)
	{
		const size_t cap = Stream_Capacity(&sub1);
		formatList->numFormats = (cap / 36);

		if ((formatList->numFormats * 36) != cap)
		{
			WLog_ERR(TAG, "Invalid short format list length: %" PRIuz "", cap);
			return ERROR_INTERNAL_ERROR;
		}

		if (formatList->numFormats)
			formats = (CLIPRDR_FORMAT*)calloc(formatList->numFormats, sizeof(CLIPRDR_FORMAT));

		if (!formats)
		{
			WLog_ERR(TAG, "calloc failed!");
			return CHANNEL_RC_NO_MEMORY;
		}

		formatList->formats = formats;

		while (Stream_GetRemainingLength(&sub1) >= 4)
		{
			Stream_Read_UINT32(&sub1, formats[index].formatId); /* formatId (4 bytes) */

			formats[index].formatName = NULL;

			/* According to MS-RDPECLIP 2.2.3.1.1.1 formatName is "a 32-byte block containing
			 * the *null-terminated* name assigned to the Clipboard Format: (32 ASCII 8 characters
			 * or 16 Unicode characters)"
			 * However, both Windows RDSH and mstsc violate this specs as seen in the following
			 * example of a transferred short format name string: [R.i.c.h. .T.e.x.t. .F.o.r.m.a.t.]
			 * These are 16 unicode charaters - *without* terminating null !
			 */

			szFormatName = (char*)Stream_Pointer(&sub1);
			wszFormatName = (WCHAR*)Stream_Pointer(&sub1);
			if (!Stream_SafeSeek(&sub1, 32))
				goto error_out;
			if (asciiNames)
			{
				if (szFormatName[0])
				{
					/* ensure null termination */
					formats[index].formatName = (char*)malloc(32 + 1);
					if (!formats[index].formatName)
					{
						WLog_ERR(TAG, "malloc failed!");
						error = CHANNEL_RC_NO_MEMORY;
						goto error_out;
					}
					CopyMemory(formats[index].formatName, szFormatName, 32);
					formats[index].formatName[32] = '\0';
				}
			}
			else
			{
				if (wszFormatName[0])
				{
					/* ConvertFromUnicode always returns a null-terminated
					 * string on success, even if the source string isn't.
					 */
					if (ConvertFromUnicode(CP_UTF8, 0, wszFormatName, 16,
					                       &(formats[index].formatName), 0, NULL, NULL) < 1)
					{
						WLog_ERR(TAG, "failed to convert short clipboard format name");
						error = ERROR_INTERNAL_ERROR;
						goto error_out;
					}
				}
			}

			index++;
		}
	}
	else
	{
		sub2 = sub1;
		while (Stream_GetRemainingLength(&sub1) > 0)
		{
			size_t rest;
			if (!Stream_SafeSeek(&sub1, 4)) /* formatId (4 bytes) */
				goto error_out;

			wszFormatName = (WCHAR*)Stream_Pointer(&sub1);
			rest = Stream_GetRemainingLength(&sub1);
			formatNameLength = _wcsnlen(wszFormatName, rest / sizeof(WCHAR));

			if (!Stream_SafeSeek(&sub1, (formatNameLength + 1) * sizeof(WCHAR)))
				goto error_out;
			formatList->numFormats++;
		}

		if (formatList->numFormats)
			formats = (CLIPRDR_FORMAT*)calloc(formatList->numFormats, sizeof(CLIPRDR_FORMAT));

		if (!formats)
		{
			WLog_ERR(TAG, "calloc failed!");
			return CHANNEL_RC_NO_MEMORY;
		}

		formatList->formats = formats;

		while (Stream_GetRemainingLength(&sub2) >= 4)
		{
			size_t rest;
			Stream_Read_UINT32(&sub2, formats[index].formatId); /* formatId (4 bytes) */

			formats[index].formatName = NULL;

			wszFormatName = (WCHAR*)Stream_Pointer(&sub2);
			rest = Stream_GetRemainingLength(&sub2);
			formatNameLength = _wcsnlen(wszFormatName, rest / sizeof(WCHAR));
			if (!Stream_SafeSeek(&sub2, (formatNameLength + 1) * sizeof(WCHAR)))
				goto error_out;

			if (formatNameLength)
			{
				if (ConvertFromUnicode(CP_UTF8, 0, wszFormatName, formatNameLength,
				                       &(formats[index].formatName), 0, NULL, NULL) < 1)
				{
					WLog_ERR(TAG, "failed to convert long clipboard format name");
					error = ERROR_INTERNAL_ERROR;
					goto error_out;
				}
			}

			index++;
		}
	}

	return error;

error_out:
	cliprdr_free_format_list(formatList);
	return error;
}

Project: FreeRDP
File: cliprdr_common.c

wStream* cliprdr_packet_file_contents_response_new(const CLIPRDR_FILE_CONTENTS_RESPONSE* response)
{
	wStream* s;

	if (!response)
		return NULL;

	s = cliprdr_packet_new(CB_FILECONTENTS_RESPONSE, response->msgFlags, 4 + response->cbRequested);

	if (!s)
		return NULL;

	cliprdr_write_file_contents_response(s, response);
	return s;
}

Project: FreeRDP
File: cliprdr_common.c

wStream* cliprdr_packet_format_list_new(const CLIPRDR_FORMAT_LIST* formatList,
                                        BOOL useLongFormatNames)
{
	wStream* s;
	UINT32 index;
	int cchWideChar;
	LPWSTR lpWideCharStr;
	int formatNameSize;
	char* szFormatName;
	WCHAR* wszFormatName;
	BOOL asciiNames = FALSE;
	CLIPRDR_FORMAT* format;

	if (formatList->msgType != CB_FORMAT_LIST)
		WLog_WARN(TAG, "[%s] called with invalid type %08" PRIx32, __FUNCTION__,
		          formatList->msgType);

	if (!useLongFormatNames)
	{
		UINT32 length = formatList->numFormats * 36;
		s = cliprdr_packet_new(CB_FORMAT_LIST, 0, length);

		if (!s)
		{
			WLog_ERR(TAG, "cliprdr_packet_new failed!");
			return NULL;
		}

		for (index = 0; index < formatList->numFormats; index++)
		{
			size_t formatNameLength = 0;
			format = (CLIPRDR_FORMAT*)&(formatList->formats[index]);
			Stream_Write_UINT32(s, format->formatId); /* formatId (4 bytes) */
			formatNameSize = 0;

			szFormatName = format->formatName;

			if (asciiNames)
			{
				if (szFormatName)
					formatNameLength = strnlen(szFormatName, 32);

				if (formatNameLength > 31)
					formatNameLength = 31;

				Stream_Write(s, szFormatName, formatNameLength);
				Stream_Zero(s, 32 - formatNameLength);
			}
			else
			{
				wszFormatName = NULL;

				if (szFormatName)
					formatNameSize =
					    ConvertToUnicode(CP_UTF8, 0, szFormatName, -1, &wszFormatName, 0);

				if (formatNameSize < 0)
					return NULL;

				if (formatNameSize > 15)
					formatNameSize = 15;

				/* size in bytes  instead of wchar */
				formatNameSize *= 2;

				if (wszFormatName)
					Stream_Write(s, wszFormatName, (size_t)formatNameSize);

				Stream_Zero(s, (size_t)(32 - formatNameSize));
				free(wszFormatName);
			}
		}
	}
	else
	{
		UINT32 length = 0;
		for (index = 0; index < formatList->numFormats; index++)
		{
			format = (CLIPRDR_FORMAT*)&(formatList->formats[index]);
			length += 4;
			formatNameSize = 2;

			if (format->formatName)
				formatNameSize =
				    MultiByteToWideChar(CP_UTF8, 0, format->formatName, -1, NULL, 0) * 2;

			if (formatNameSize < 0)
				return NULL;

			length += (UINT32)formatNameSize;
		}

		s = cliprdr_packet_new(CB_FORMAT_LIST, 0, length);

		if (!s)
		{
			WLog_ERR(TAG, "cliprdr_packet_new failed!");
			return NULL;
		}

		for (index = 0; index < formatList->numFormats; index++)
		{
			format = (CLIPRDR_FORMAT*)&(formatList->formats[index]);
			Stream_Write_UINT32(s, format->formatId); /* formatId (4 bytes) */

			if (format->formatName)
			{
				const size_t cap = Stream_Capacity(s);
				const size_t pos = Stream_GetPosition(s);
				const size_t rem = cap - pos;
				if ((cap < pos) || ((rem / 2) > INT_MAX))
					return NULL;

				lpWideCharStr = (LPWSTR)Stream_Pointer(s);
				cchWideChar = (int)(rem / 2);
				formatNameSize = MultiByteToWideChar(CP_UTF8, 0, format->formatName, -1,
				                                     lpWideCharStr, cchWideChar) *
				                 2;
				if (formatNameSize < 0)
					return NULL;
				Stream_Seek(s, (size_t)formatNameSize);
			}
			else
			{
				Stream_Write_UINT16(s, 0);
			}
		}
	}

	return s;
}

Project: FreeRDP
File: cliprdr_common.c

UINT cliprdr_read_file_contents_request(wStream* s, CLIPRDR_FILE_CONTENTS_REQUEST* request)
{
	if (Stream_GetRemainingLength(s) < 24)
	{
		WLog_ERR(TAG, "not enough remaining data");
		return ERROR_INVALID_DATA;
	}

	request->haveClipDataId = FALSE;
	Stream_Read_UINT32(s, request->streamId);      /* streamId (4 bytes) */
	Stream_Read_UINT32(s, request->listIndex);     /* listIndex (4 bytes) */
	Stream_Read_UINT32(s, request->dwFlags);       /* dwFlags (4 bytes) */
	Stream_Read_UINT32(s, request->nPositionLow);  /* nPositionLow (4 bytes) */
	Stream_Read_UINT32(s, request->nPositionHigh); /* nPositionHigh (4 bytes) */
	Stream_Read_UINT32(s, request->cbRequested);   /* cbRequested (4 bytes) */

	if (Stream_GetRemainingLength(s) >= 4)
	{
		Stream_Read_UINT32(s, request->clipDataId); /* clipDataId (4 bytes) */
		request->haveClipDataId = TRUE;
	}

	if (!cliprdr_validate_file_contents_request(request))
		return ERROR_BAD_ARGUMENTS;

	return CHANNEL_RC_OK;
}

Project: FreeRDP
File: cliprdr_common.c

UINT cliprdr_read_unlock_clipdata(wStream* s, CLIPRDR_UNLOCK_CLIPBOARD_DATA* unlockClipboardData)
{
	if (Stream_GetRemainingLength(s) < 4)
	{
		WLog_ERR(TAG, "not enough remaining data");
		return ERROR_INVALID_DATA;
	}

	Stream_Read_UINT32(s, unlockClipboardData->clipDataId); /* clipDataId (4 bytes) */
	return CHANNEL_RC_OK;
}

Project: FreeRDP
File: cliprdr_common.c

UINT cliprdr_read_file_contents_response(wStream* s, CLIPRDR_FILE_CONTENTS_RESPONSE* response)
{
	if (Stream_GetRemainingLength(s) < 4)
	{
		WLog_ERR(TAG, "not enough remaining data");
		return ERROR_INVALID_DATA;
	}

	Stream_Read_UINT32(s, response->streamId);   /* streamId (4 bytes) */
	response->requestedData = Stream_Pointer(s); /* requestedFileContentsData */
	response->cbRequested = response->dataLen - 4;
	return CHANNEL_RC_OK;
}