FreeRDP/libfreerdp/core/utils.c

/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * Terminal Server Gateway (utils)
 *
 * Copyright 2021 Armin Novak <armin.novak@thincast.com>
 * Copyright 2021 Thincast Technologies GmbH
 *
 * 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 <freerdp/config.h>

#include "settings.h"

#include <winpr/assert.h>

#include <freerdp/freerdp.h>
#include <freerdp/channels/cliprdr.h>
#include <freerdp/channels/rdpdr.h>

#include <freerdp/log.h>
#define TAG FREERDP_TAG("core.gateway.utils")

#include "utils.h"

#include "../core/rdp.h"

BOOL utils_str_copy(const char* value, char** dst)
{
	WINPR_ASSERT(dst);

	free(*dst);
	*dst = NULL;
	if (!value)
		return TRUE;

	(*dst) = _strdup(value);
	return (*dst) != NULL;
}

static BOOL utils_copy_smartcard_settings(const rdpSettings* settings, rdpSettings* origSettings)
{
	/* update original settings with provided smart card settings */
	origSettings->SmartcardLogon = settings->SmartcardLogon;
	origSettings->PasswordIsSmartcardPin = settings->PasswordIsSmartcardPin;
	if (!utils_str_copy(settings->ReaderName, &origSettings->ReaderName))
		return FALSE;
	if (!utils_str_copy(settings->CspName, &origSettings->CspName))
		return FALSE;
	if (!utils_str_copy(settings->ContainerName, &origSettings->ContainerName))
		return FALSE;

	return TRUE;
}

auth_status utils_authenticate_gateway(freerdp* instance, rdp_auth_reason reason)
{
	rdpSettings* settings = NULL;
	rdpSettings* origSettings = NULL;
	BOOL prompt = FALSE;
	BOOL proceed = 0;

	WINPR_ASSERT(instance);
	WINPR_ASSERT(instance->context);
	WINPR_ASSERT(instance->context->settings);
	WINPR_ASSERT(instance->context->rdp);
	WINPR_ASSERT(instance->context->rdp->originalSettings);

	settings = instance->context->settings;
	origSettings = instance->context->rdp->originalSettings;

	if (freerdp_shall_disconnect_context(instance->context))
		return AUTH_FAILED;

	if (utils_str_is_empty(freerdp_settings_get_string(settings, FreeRDP_GatewayPassword)))
		prompt = TRUE;
	if (utils_str_is_empty(freerdp_settings_get_string(settings, FreeRDP_GatewayUsername)))
		prompt = TRUE;

	if (!prompt)
		return AUTH_SKIP;

	if (!instance->GatewayAuthenticate && !instance->AuthenticateEx)
		return AUTH_NO_CREDENTIALS;

	if (!instance->GatewayAuthenticate)
	{
		proceed =
		    instance->AuthenticateEx(instance, &settings->GatewayUsername,
		                             &settings->GatewayPassword, &settings->GatewayDomain, reason);
		if (!proceed)
			return AUTH_CANCELLED;
	}
	else
	{
		proceed =
		    instance->GatewayAuthenticate(instance, &settings->GatewayUsername,
		                                  &settings->GatewayPassword, &settings->GatewayDomain);
		if (!proceed)
			return AUTH_CANCELLED;
	}

	if (utils_str_is_empty(settings->GatewayUsername) ||
	    utils_str_is_empty(settings->GatewayPassword))
		return AUTH_NO_CREDENTIALS;

	if (!utils_sync_credentials(settings, FALSE))
		return AUTH_FAILED;

	/* update original settings with provided user credentials */
	if (!utils_str_copy(settings->GatewayUsername, &origSettings->GatewayUsername))
		return AUTH_FAILED;
	if (!utils_str_copy(settings->GatewayDomain, &origSettings->GatewayDomain))
		return AUTH_FAILED;
	if (!utils_str_copy(settings->GatewayPassword, &origSettings->GatewayPassword))
		return AUTH_FAILED;
	if (!utils_sync_credentials(origSettings, FALSE))
		return AUTH_FAILED;

	if (!utils_copy_smartcard_settings(settings, origSettings))
		return AUTH_FAILED;

	return AUTH_SUCCESS;
}

auth_status utils_authenticate(freerdp* instance, rdp_auth_reason reason, BOOL override)
{
	rdpSettings* settings = NULL;
	rdpSettings* origSettings = NULL;
	BOOL prompt = !override;
	BOOL proceed = 0;

	WINPR_ASSERT(instance);
	WINPR_ASSERT(instance->context);
	WINPR_ASSERT(instance->context->settings);
	WINPR_ASSERT(instance->context->rdp);
	WINPR_ASSERT(instance->context->rdp->originalSettings);

	settings = instance->context->settings;
	origSettings = instance->context->rdp->originalSettings;

	if (freerdp_shall_disconnect_context(instance->context))
		return AUTH_FAILED;

	if (settings->ConnectChildSession)
		return AUTH_NO_CREDENTIALS;

	/* Ask for auth data if no or an empty username was specified or no password was given */
	if (utils_str_is_empty(freerdp_settings_get_string(settings, FreeRDP_Username)) ||
	    (settings->Password == NULL && settings->RedirectionPassword == NULL))
		prompt = TRUE;

	if (!prompt)
		return AUTH_SKIP;

	switch (reason)
	{
		case AUTH_RDP:
		case AUTH_TLS:
			if (settings->SmartcardLogon)
			{
				if (!utils_str_is_empty(settings->Password))
				{
					WLog_INFO(TAG, "Authentication via smartcard");
					return AUTH_SUCCESS;
				}
				reason = AUTH_SMARTCARD_PIN;
			}
			break;
		case AUTH_NLA:
			if (settings->SmartcardLogon)
				reason = AUTH_SMARTCARD_PIN;
			break;
		default:
			break;
	}

	/* If no callback is specified still continue connection */
	if (!instance->Authenticate && !instance->AuthenticateEx)
		return AUTH_NO_CREDENTIALS;

	if (!instance->Authenticate)
	{
		proceed = instance->AuthenticateEx(instance, &settings->Username, &settings->Password,
		                                   &settings->Domain, reason);
		if (!proceed)
			return AUTH_CANCELLED;
	}
	else
	{
		proceed = instance->Authenticate(instance, &settings->Username, &settings->Password,
		                                 &settings->Domain);
		if (!proceed)
			return AUTH_NO_CREDENTIALS;
	}

	if (utils_str_is_empty(settings->Username) || utils_str_is_empty(settings->Password))
		return AUTH_NO_CREDENTIALS;

	if (!utils_sync_credentials(settings, TRUE))
		return AUTH_FAILED;

	/* update original settings with provided user credentials */
	if (!utils_str_copy(settings->Username, &origSettings->Username))
		return AUTH_FAILED;
	if (!utils_str_copy(settings->Domain, &origSettings->Domain))
		return AUTH_FAILED;
	if (!utils_str_copy(settings->Password, &origSettings->Password))
		return AUTH_FAILED;
	if (!utils_sync_credentials(origSettings, TRUE))
		return AUTH_FAILED;

	if (!utils_copy_smartcard_settings(settings, origSettings))
		return AUTH_FAILED;

	return AUTH_SUCCESS;
}

BOOL utils_sync_credentials(rdpSettings* settings, BOOL toGateway)
{
	WINPR_ASSERT(settings);
	if (!settings->GatewayUseSameCredentials)
		return TRUE;

	if (toGateway)
	{
		if (!utils_str_copy(settings->Username, &settings->GatewayUsername))
			return FALSE;
		if (!utils_str_copy(settings->Domain, &settings->GatewayDomain))
			return FALSE;
		if (!utils_str_copy(settings->Password, &settings->GatewayPassword))
			return FALSE;
	}
	else
	{
		if (!utils_str_copy(settings->GatewayUsername, &settings->Username))
			return FALSE;
		if (!utils_str_copy(settings->GatewayDomain, &settings->Domain))
			return FALSE;
		if (!utils_str_copy(settings->GatewayPassword, &settings->Password))
			return FALSE;
	}
	return TRUE;
}

BOOL utils_str_is_empty(const char* str)
{
	if (!str)
		return TRUE;
	if (*str == '\0')
		return TRUE;
	return FALSE;
}

BOOL utils_abort_connect(rdpRdp* rdp)
{
	if (!rdp)
		return FALSE;

	return SetEvent(rdp->abortEvent);
}

BOOL utils_reset_abort(rdpRdp* rdp)
{
	WINPR_ASSERT(rdp);

	return ResetEvent(rdp->abortEvent);
}

HANDLE utils_get_abort_event(rdpRdp* rdp)
{
	WINPR_ASSERT(rdp);
	return rdp->abortEvent;
}

BOOL utils_abort_event_is_set(const rdpRdp* rdp)
{
	DWORD status = 0;
	WINPR_ASSERT(rdp);
	status = WaitForSingleObject(rdp->abortEvent, 0);
	return status == WAIT_OBJECT_0;
}

const char* utils_is_vsock(const char* hostname)
{
	if (!hostname)
		return NULL;

	const char vsock[8] = "vsock://";
	if (strncmp(hostname, vsock, sizeof(vsock)) == 0)
		return &hostname[sizeof(vsock)];
	return NULL;
}

static BOOL remove_rdpdr_type(rdpSettings* settings, UINT32 type)
{
	RDPDR_DEVICE* printer = NULL;
	do
	{
		printer = freerdp_device_collection_find_type(settings, type);
		freerdp_device_collection_del(settings, printer);
		freerdp_device_free(printer);
	} while (printer);
	return TRUE;
}

static BOOL disable_clipboard(rdpSettings* settings)
{
	if (!freerdp_settings_set_bool(settings, FreeRDP_RedirectClipboard, FALSE))
		return FALSE;
	freerdp_static_channel_collection_del(settings, CLIPRDR_SVC_CHANNEL_NAME);
	return TRUE;
}

static BOOL disable_drive(rdpSettings* settings)
{
	if (!freerdp_settings_set_bool(settings, FreeRDP_RedirectDrives, FALSE))
		return FALSE;
	if (!freerdp_settings_set_bool(settings, FreeRDP_RedirectHomeDrive, FALSE))
		return FALSE;

	return remove_rdpdr_type(settings, RDPDR_DTYP_FILESYSTEM);
}

static BOOL disable_printers(rdpSettings* settings)
{
	if (!freerdp_settings_set_bool(settings, FreeRDP_RedirectPrinters, FALSE))
		return FALSE;

	return remove_rdpdr_type(settings, RDPDR_DTYP_PRINT);
}

static BOOL disable_port(rdpSettings* settings)
{
	if (!freerdp_settings_set_bool(settings, FreeRDP_RedirectParallelPorts, FALSE))
		return FALSE;
	if (!freerdp_settings_set_bool(settings, FreeRDP_RedirectSerialPorts, FALSE))
		return FALSE;
	if (!remove_rdpdr_type(settings, RDPDR_DTYP_SERIAL))
		return FALSE;
	return remove_rdpdr_type(settings, RDPDR_DTYP_PARALLEL);
}

static BOOL disable_pnp(rdpSettings* settings)
{
	// TODO(akallabeth): [MS-RDPEPNP] related stuff is disabled.
	return TRUE;
}

static BOOL apply_gw_policy(rdpContext* context)
{
	WINPR_ASSERT(context);
	return utils_reload_channels(context);
}

BOOL utils_apply_gateway_policy(wLog* log, rdpContext* context, UINT32 flags, const char* module)
{
	WINPR_ASSERT(log);
	WINPR_ASSERT(context);

	rdpSettings* settings = context->settings;
	WINPR_ASSERT(settings);

	if (flags & HTTP_TUNNEL_REDIR_ENABLE_ALL)
	{
		WLog_Print(log, WLOG_DEBUG, "[%s] policy allows all redirections", module);
	}
	else if (freerdp_settings_get_bool(settings, FreeRDP_GatewayIgnoreRedirectionPolicy))
	{
		char buffer[128] = { 0 };
		WLog_Print(log, WLOG_INFO, "[%s] policy ignored on user request %s", module,
		           utils_redir_flags_to_string(flags, buffer, sizeof(buffer)));
	}
	else if (flags & HTTP_TUNNEL_REDIR_DISABLE_ALL)
	{
		WLog_Print(log, WLOG_INFO, "[%s] policy denies all redirections", module);
		if (!disable_drive(settings))
			return FALSE;
		if (!disable_printers(settings))
			return FALSE;
		if (!disable_clipboard(settings))
			return FALSE;
		if (!disable_port(settings))
			return FALSE;
		if (!disable_pnp(settings))
			return FALSE;
		if (!apply_gw_policy(context))
			return FALSE;
	}
	else
	{
		if (flags & HTTP_TUNNEL_REDIR_DISABLE_DRIVE)
		{
			WLog_Print(log, WLOG_INFO, "[%s] policy denies drive redirections", module);
			if (!disable_drive(settings))
				return FALSE;
		}
		if (flags & HTTP_TUNNEL_REDIR_DISABLE_PRINTER)
		{
			WLog_Print(log, WLOG_INFO, "[%s] policy denies printer redirections", module);
			if (!disable_printers(settings))
				return FALSE;
		}
		if (flags & HTTP_TUNNEL_REDIR_DISABLE_PORT)
		{
			WLog_Print(log, WLOG_INFO, "[%s] policy denies port redirections", module);
			if (!disable_port(settings))
				return FALSE;
		}
		if (flags & HTTP_TUNNEL_REDIR_DISABLE_CLIPBOARD)
		{
			WLog_Print(log, WLOG_INFO, "[%s] policy denies clipboard redirections", module);
			if (!disable_clipboard(settings))
				return FALSE;
		}
		if (flags & HTTP_TUNNEL_REDIR_DISABLE_PNP)
		{
			WLog_Print(log, WLOG_INFO, "[%s] policy denies PNP redirections", module);
			if (!disable_pnp(settings))
				return FALSE;
		}
		if (flags != 0)
		{
			if (!apply_gw_policy(context))
				return FALSE;
		}
	}
	return TRUE;
}

char* utils_redir_flags_to_string(UINT32 flags, char* buffer, size_t size)
{
	winpr_str_append("{", buffer, size, "");
	if (flags & HTTP_TUNNEL_REDIR_ENABLE_ALL)
		winpr_str_append("ENABLE_ALL", buffer, size, "|");
	if (flags & HTTP_TUNNEL_REDIR_DISABLE_ALL)
		winpr_str_append("DISABLE_ALL", buffer, size, "|");
	if (flags & HTTP_TUNNEL_REDIR_DISABLE_DRIVE)
		winpr_str_append("DISABLE_DRIVE", buffer, size, "|");
	if (flags & HTTP_TUNNEL_REDIR_DISABLE_PRINTER)
		winpr_str_append("DISABLE_PRINTER", buffer, size, "|");
	if (flags & HTTP_TUNNEL_REDIR_DISABLE_PORT)
		winpr_str_append("DISABLE_PORT", buffer, size, "|");
	if (flags & HTTP_TUNNEL_REDIR_DISABLE_CLIPBOARD)
		winpr_str_append("DISABLE_CLIPBOARD", buffer, size, "|");
	if (flags & HTTP_TUNNEL_REDIR_DISABLE_PNP)
		winpr_str_append("DISABLE_PNP", buffer, size, "|");

	char fbuffer[16] = { 0 };
	(void)_snprintf(fbuffer, sizeof(fbuffer), "[0x%08" PRIx32 "]", flags);

	winpr_str_append(fbuffer, buffer, size, " ");
	winpr_str_append("{", buffer, size, "}");
	return buffer;
}

BOOL utils_reload_channels(rdpContext* context)
{
	WINPR_ASSERT(context);

	freerdp_channels_disconnect(context->channels, context->instance);
	freerdp_channels_close(context->channels, context->instance);
	freerdp_channels_free(context->channels);
	context->channels = freerdp_channels_new(context->instance);
	WINPR_ASSERT(context->channels);

	BOOL rc = TRUE;
	IFCALLRET(context->instance->LoadChannels, rc, context->instance);
	if (rc)
		return freerdp_channels_pre_connect(context->channels, context->instance) == CHANNEL_RC_OK;
	return rc;
}