esp-idf/components/openssl/platform/ssl_pm.c

720 lines
19 KiB
C

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// 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 "ssl_pm.h"
#include "ssl_port.h"
#include "ssl_dbg.h"
/* mbedtls include */
#include "mbedtls/platform.h"
#include "mbedtls/net_sockets.h"
#include "mbedtls/debug.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/error.h"
#include "mbedtls/certs.h"
#define X509_INFO_STRING_LENGTH 8192
struct ssl_pm
{
/* local socket file description */
mbedtls_net_context fd;
/* remote client socket file description */
mbedtls_net_context cl_fd;
mbedtls_ssl_config conf;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_ssl_context ssl;
mbedtls_entropy_context entropy;
};
struct x509_pm
{
mbedtls_x509_crt *x509_crt;
mbedtls_x509_crt *ex_crt;
};
struct pkey_pm
{
mbedtls_pk_context *pkey;
mbedtls_pk_context *ex_pkey;
};
unsigned int max_content_len;
/*********************************************************************************************/
/************************************ SSL arch interface *************************************/
#ifdef CONFIG_OPENSSL_LOWLEVEL_DEBUG
/* mbedtls debug level */
#define MBEDTLS_DEBUG_LEVEL 4
/**
* @brief mbedtls debug function
*/
static void ssl_platform_debug(void *ctx, int level,
const char *file, int line,
const char *str)
{
/* Shorten 'file' from the whole file path to just the filename
This is a bit wasteful because the macros are compiled in with
the full _FILE_ path in each case.
*/
char *file_sep = rindex(file, '/');
if(file_sep)
file = file_sep + 1;
SSL_DEBUG(SSL_DEBUG_ON, "%s:%d %s", file, line, str);
}
#endif
/**
* @brief create SSL low-level object
*/
int ssl_pm_new(SSL *ssl)
{
struct ssl_pm *ssl_pm;
int ret;
const unsigned char pers[] = "OpenSSL PM";
size_t pers_len = sizeof(pers);
int endpoint;
int version;
const SSL_METHOD *method = ssl->method;
ssl_pm = ssl_mem_zalloc(sizeof(struct ssl_pm));
if (!ssl_pm) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "no enough memory > (ssl_pm)");
goto no_mem;
}
max_content_len = ssl->ctx->read_buffer_len;
mbedtls_net_init(&ssl_pm->fd);
mbedtls_net_init(&ssl_pm->cl_fd);
mbedtls_ssl_config_init(&ssl_pm->conf);
mbedtls_ctr_drbg_init(&ssl_pm->ctr_drbg);
mbedtls_entropy_init(&ssl_pm->entropy);
mbedtls_ssl_init(&ssl_pm->ssl);
ret = mbedtls_ctr_drbg_seed(&ssl_pm->ctr_drbg, mbedtls_entropy_func, &ssl_pm->entropy, pers, pers_len);
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ctr_drbg_seed() return -0x%x", -ret);
goto mbedtls_err1;
}
if (method->endpoint) {
endpoint = MBEDTLS_SSL_IS_SERVER;
} else {
endpoint = MBEDTLS_SSL_IS_CLIENT;
}
ret = mbedtls_ssl_config_defaults(&ssl_pm->conf, endpoint, MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT);
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_config_defaults() return -0x%x", -ret);
goto mbedtls_err2;
}
if (TLS_ANY_VERSION != ssl->version) {
if (TLS1_2_VERSION == ssl->version)
version = MBEDTLS_SSL_MINOR_VERSION_3;
else if (TLS1_1_VERSION == ssl->version)
version = MBEDTLS_SSL_MINOR_VERSION_2;
else if (TLS1_VERSION == ssl->version)
version = MBEDTLS_SSL_MINOR_VERSION_1;
else
version = MBEDTLS_SSL_MINOR_VERSION_0;
mbedtls_ssl_conf_max_version(&ssl_pm->conf, MBEDTLS_SSL_MAJOR_VERSION_3, version);
mbedtls_ssl_conf_min_version(&ssl_pm->conf, MBEDTLS_SSL_MAJOR_VERSION_3, version);
} else {
mbedtls_ssl_conf_max_version(&ssl_pm->conf, MBEDTLS_SSL_MAJOR_VERSION_3, MBEDTLS_SSL_MINOR_VERSION_3);
mbedtls_ssl_conf_min_version(&ssl_pm->conf, MBEDTLS_SSL_MAJOR_VERSION_3, MBEDTLS_SSL_MINOR_VERSION_0);
}
if (ssl->ctx->ssl_alpn.alpn_status == ALPN_ENABLE) {
#ifdef MBEDTLS_SSL_ALPN
mbedtls_ssl_conf_alpn_protocols( &ssl_pm->conf, ssl->ctx->ssl_alpn.alpn_list );
#else
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "CONFIG_MBEDTLS_SSL_ALPN must be enabled to use ALPN", -1);
#endif // MBEDTLS_SSL_ALPN
}
mbedtls_ssl_conf_rng(&ssl_pm->conf, mbedtls_ctr_drbg_random, &ssl_pm->ctr_drbg);
#ifdef CONFIG_OPENSSL_LOWLEVEL_DEBUG
mbedtls_debug_set_threshold(MBEDTLS_DEBUG_LEVEL);
mbedtls_ssl_conf_dbg(&ssl_pm->conf, ssl_platform_debug, NULL);
#else
mbedtls_ssl_conf_dbg(&ssl_pm->conf, NULL, NULL);
#endif
ret = mbedtls_ssl_setup(&ssl_pm->ssl, &ssl_pm->conf);
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_setup() return -0x%x", -ret);
goto mbedtls_err2;
}
mbedtls_ssl_set_bio(&ssl_pm->ssl, &ssl_pm->fd, mbedtls_net_send, mbedtls_net_recv, NULL);
ssl->ssl_pm = ssl_pm;
return 0;
mbedtls_err2:
mbedtls_ssl_config_free(&ssl_pm->conf);
mbedtls_ctr_drbg_free(&ssl_pm->ctr_drbg);
mbedtls_err1:
mbedtls_entropy_free(&ssl_pm->entropy);
ssl_mem_free(ssl_pm);
no_mem:
return -1;
}
/**
* @brief free SSL low-level object
*/
void ssl_pm_free(SSL *ssl)
{
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
mbedtls_ctr_drbg_free(&ssl_pm->ctr_drbg);
mbedtls_entropy_free(&ssl_pm->entropy);
mbedtls_ssl_config_free(&ssl_pm->conf);
mbedtls_ssl_free(&ssl_pm->ssl);
ssl_mem_free(ssl_pm);
ssl->ssl_pm = NULL;
}
/**
* @brief reload SSL low-level certification object
*/
static int ssl_pm_reload_crt(SSL *ssl)
{
int ret;
int mode = MBEDTLS_SSL_VERIFY_UNSET;
struct ssl_pm *ssl_pm = ssl->ssl_pm;
struct x509_pm *ca_pm = (struct x509_pm *)ssl->client_CA->x509_pm;
struct pkey_pm *pkey_pm = (struct pkey_pm *)ssl->cert->pkey->pkey_pm;
struct x509_pm *crt_pm = (struct x509_pm *)ssl->cert->x509->x509_pm;
/* OpenSSL verification modes outline (see `man SSL_set_verify` for more details)
*
* | openssl mode | Server | Client |
* | SSL_VERIFY_NONE | will not send a client certificate request | server certificate which will be checked |
* handshake will be continued regardless |
* | SSL_VERIFY_PEER | depends on SSL_VERIFY_FAIL_IF_NO_PEER_CERT | handshake is terminated if verify fails |
* (unless anonymous ciphers--not supported |
* | SSL_VERIFY_FAIL_IF_NO_PEER_CERT | handshake is terminated if | ignored |
* client cert verify fails | |
*/
if (ssl->method->endpoint == MBEDTLS_SSL_IS_SERVER) {
if (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)
mode = MBEDTLS_SSL_VERIFY_REQUIRED;
else if (ssl->verify_mode & SSL_VERIFY_PEER)
mode = MBEDTLS_SSL_VERIFY_OPTIONAL;
else if (ssl->verify_mode == SSL_VERIFY_NONE)
mode = MBEDTLS_SSL_VERIFY_NONE;
} else if (ssl->method->endpoint == MBEDTLS_SSL_IS_CLIENT) {
if (ssl->verify_mode & SSL_VERIFY_PEER)
mode = MBEDTLS_SSL_VERIFY_REQUIRED;
else if (ssl->verify_mode == SSL_VERIFY_NONE)
mode = MBEDTLS_SSL_VERIFY_NONE;
}
mbedtls_ssl_conf_authmode(&ssl_pm->conf, mode);
if (ca_pm->x509_crt) {
mbedtls_ssl_conf_ca_chain(&ssl_pm->conf, ca_pm->x509_crt, NULL);
} else if (ca_pm->ex_crt) {
mbedtls_ssl_conf_ca_chain(&ssl_pm->conf, ca_pm->ex_crt, NULL);
}
if (crt_pm->x509_crt && pkey_pm->pkey) {
ret = mbedtls_ssl_conf_own_cert(&ssl_pm->conf, crt_pm->x509_crt, pkey_pm->pkey);
} else if (crt_pm->ex_crt && pkey_pm->ex_pkey) {
ret = mbedtls_ssl_conf_own_cert(&ssl_pm->conf, crt_pm->ex_crt, pkey_pm->ex_pkey);
} else {
ret = 0;
}
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_conf_own_cert() return -0x%x", -ret);
ret = -1;
}
return ret;
}
/*
* Perform the mbedtls SSL handshake instead of mbedtls_ssl_handshake.
* We can add debug here.
*/
static int mbedtls_handshake( mbedtls_ssl_context *ssl )
{
int ret = 0;
while (ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER) {
ret = mbedtls_ssl_handshake_step(ssl);
SSL_DEBUG(SSL_PLATFORM_DEBUG_LEVEL, "ssl ret %d state %d", ret, ssl->state);
if (ret != 0)
break;
}
return ret;
}
int ssl_pm_handshake(SSL *ssl)
{
int ret;
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
ret = ssl_pm_reload_crt(ssl);
if (ret)
return 0;
ssl_speed_up_enter();
while((ret = mbedtls_handshake(&ssl_pm->ssl)) != 0) {
if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
break;
}
}
ssl_speed_up_exit();
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_handshake() return -0x%x", -ret);
ret = 0;
} else {
struct x509_pm *x509_pm = (struct x509_pm *)ssl->session->peer->x509_pm;
x509_pm->ex_crt = (mbedtls_x509_crt *)mbedtls_ssl_get_peer_cert(&ssl_pm->ssl);
ret = 1;
}
return ret;
}
int ssl_pm_shutdown(SSL *ssl)
{
int ret;
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
ret = mbedtls_ssl_close_notify(&ssl_pm->ssl);
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_close_notify() return -0x%x", -ret);
ret = -1;
} else {
struct x509_pm *x509_pm = (struct x509_pm *)ssl->session->peer->x509_pm;
x509_pm->ex_crt = NULL;
}
return ret;
}
int ssl_pm_clear(SSL *ssl)
{
return ssl_pm_shutdown(ssl);
}
int ssl_pm_read(SSL *ssl, void *buffer, int len)
{
int ret;
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
ret = mbedtls_ssl_read(&ssl_pm->ssl, buffer, len);
if (ret < 0) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_read() return -0x%x", -ret);
ret = -1;
}
return ret;
}
int ssl_pm_send(SSL *ssl, const void *buffer, int len)
{
int ret;
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
ret = mbedtls_ssl_write(&ssl_pm->ssl, buffer, len);
if (ret < 0) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_write() return -0x%x", -ret);
ret = -1;
}
return ret;
}
int ssl_pm_pending(const SSL *ssl)
{
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
return mbedtls_ssl_get_bytes_avail(&ssl_pm->ssl);
}
void ssl_pm_set_fd(SSL *ssl, int fd, int mode)
{
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
ssl_pm->fd.fd = fd;
}
void ssl_pm_set_hostname(SSL *ssl, const char *hostname)
{
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
mbedtls_ssl_set_hostname(&ssl_pm->ssl, hostname);
}
int ssl_pm_get_fd(const SSL *ssl, int mode)
{
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
return ssl_pm->fd.fd;
}
OSSL_HANDSHAKE_STATE ssl_pm_get_state(const SSL *ssl)
{
OSSL_HANDSHAKE_STATE state;
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
switch (ssl_pm->ssl.state)
{
case MBEDTLS_SSL_CLIENT_HELLO:
state = TLS_ST_CW_CLNT_HELLO;
break;
case MBEDTLS_SSL_SERVER_HELLO:
state = TLS_ST_SW_SRVR_HELLO;
break;
case MBEDTLS_SSL_SERVER_CERTIFICATE:
state = TLS_ST_SW_CERT;
break;
case MBEDTLS_SSL_SERVER_HELLO_DONE:
state = TLS_ST_SW_SRVR_DONE;
break;
case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
state = TLS_ST_CW_KEY_EXCH;
break;
case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
state = TLS_ST_CW_CHANGE;
break;
case MBEDTLS_SSL_CLIENT_FINISHED:
state = TLS_ST_CW_FINISHED;
break;
case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
state = TLS_ST_SW_CHANGE;
break;
case MBEDTLS_SSL_SERVER_FINISHED:
state = TLS_ST_SW_FINISHED;
break;
case MBEDTLS_SSL_CLIENT_CERTIFICATE:
state = TLS_ST_CW_CERT;
break;
case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
state = TLS_ST_SR_KEY_EXCH;
break;
case MBEDTLS_SSL_SERVER_NEW_SESSION_TICKET:
state = TLS_ST_SW_SESSION_TICKET;
break;
case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
state = TLS_ST_SW_CERT_REQ;
break;
case MBEDTLS_SSL_HANDSHAKE_OVER:
state = TLS_ST_OK;
break;
default :
state = TLS_ST_BEFORE;
break;
}
return state;
}
int x509_pm_show_info(X509 *x)
{
int ret;
char *buf;
mbedtls_x509_crt *x509_crt;
struct x509_pm *x509_pm = x->x509_pm;
if (x509_pm->x509_crt)
x509_crt = x509_pm->x509_crt;
else if (x509_pm->ex_crt)
x509_crt = x509_pm->ex_crt;
else
x509_crt = NULL;
if (!x509_crt)
return -1;
buf = ssl_mem_malloc(X509_INFO_STRING_LENGTH);
if (!buf) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "no enough memory > (buf)");
goto no_mem;
}
ret = mbedtls_x509_crt_info(buf, X509_INFO_STRING_LENGTH - 1, "", x509_crt);
if (ret <= 0) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_x509_crt_info() return -0x%x", -ret);
goto mbedtls_err1;
}
buf[ret] = 0;
ssl_mem_free(buf);
SSL_DEBUG(SSL_DEBUG_ON, "%s", buf);
return 0;
mbedtls_err1:
ssl_mem_free(buf);
no_mem:
return -1;
}
int x509_pm_new(X509 *x, X509 *m_x)
{
struct x509_pm *x509_pm;
x509_pm = ssl_mem_zalloc(sizeof(struct x509_pm));
if (!x509_pm) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "no enough memory > (x509_pm)");
goto failed1;
}
x->x509_pm = x509_pm;
if (m_x) {
struct x509_pm *m_x509_pm = (struct x509_pm *)m_x->x509_pm;
x509_pm->ex_crt = m_x509_pm->x509_crt;
}
return 0;
failed1:
return -1;
}
void x509_pm_free(X509 *x)
{
struct x509_pm *x509_pm = (struct x509_pm *)x->x509_pm;
if (x509_pm->x509_crt) {
mbedtls_x509_crt_free(x509_pm->x509_crt);
ssl_mem_free(x509_pm->x509_crt);
x509_pm->x509_crt = NULL;
}
ssl_mem_free(x->x509_pm);
x->x509_pm = NULL;
}
int x509_pm_load(X509 *x, const unsigned char *buffer, int len)
{
int ret;
unsigned char *load_buf;
struct x509_pm *x509_pm = (struct x509_pm *)x->x509_pm;
if (x509_pm->x509_crt)
mbedtls_x509_crt_free(x509_pm->x509_crt);
if (!x509_pm->x509_crt) {
x509_pm->x509_crt = ssl_mem_malloc(sizeof(mbedtls_x509_crt));
if (!x509_pm->x509_crt) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "no enough memory > (x509_pm->x509_crt)");
goto no_mem;
}
}
load_buf = ssl_mem_malloc(len + 1);
if (!load_buf) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "no enough memory > (load_buf)");
goto failed;
}
ssl_memcpy(load_buf, buffer, len);
load_buf[len] = '\0';
mbedtls_x509_crt_init(x509_pm->x509_crt);
ret = mbedtls_x509_crt_parse(x509_pm->x509_crt, load_buf, len + 1);
ssl_mem_free(load_buf);
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_x509_crt_parse return -0x%x", -ret);
goto failed;
}
return 0;
failed:
mbedtls_x509_crt_free(x509_pm->x509_crt);
ssl_mem_free(x509_pm->x509_crt);
x509_pm->x509_crt = NULL;
no_mem:
return -1;
}
int pkey_pm_new(EVP_PKEY *pk, EVP_PKEY *m_pkey)
{
struct pkey_pm *pkey_pm;
pkey_pm = ssl_mem_zalloc(sizeof(struct pkey_pm));
if (!pkey_pm)
return -1;
pk->pkey_pm = pkey_pm;
if (m_pkey) {
struct pkey_pm *m_pkey_pm = (struct pkey_pm *)m_pkey->pkey_pm;
pkey_pm->ex_pkey = m_pkey_pm->pkey;
}
return 0;
}
void pkey_pm_free(EVP_PKEY *pk)
{
struct pkey_pm *pkey_pm = (struct pkey_pm *)pk->pkey_pm;
if (pkey_pm->pkey) {
mbedtls_pk_free(pkey_pm->pkey);
ssl_mem_free(pkey_pm->pkey);
pkey_pm->pkey = NULL;
}
ssl_mem_free(pk->pkey_pm);
pk->pkey_pm = NULL;
}
int pkey_pm_load(EVP_PKEY *pk, const unsigned char *buffer, int len)
{
int ret;
unsigned char *load_buf;
struct pkey_pm *pkey_pm = (struct pkey_pm *)pk->pkey_pm;
if (pkey_pm->pkey)
mbedtls_pk_free(pkey_pm->pkey);
if (!pkey_pm->pkey) {
pkey_pm->pkey = ssl_mem_malloc(sizeof(mbedtls_pk_context));
if (!pkey_pm->pkey) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "no enough memory > (pkey_pm->pkey)");
goto no_mem;
}
}
load_buf = ssl_mem_malloc(len + 1);
if (!load_buf) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "no enough memory > (load_buf)");
goto failed;
}
ssl_memcpy(load_buf, buffer, len);
load_buf[len] = '\0';
mbedtls_pk_init(pkey_pm->pkey);
ret = mbedtls_pk_parse_key(pkey_pm->pkey, load_buf, len + 1, NULL, 0);
ssl_mem_free(load_buf);
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_pk_parse_key return -0x%x", -ret);
goto failed;
}
return 0;
failed:
mbedtls_pk_free(pkey_pm->pkey);
ssl_mem_free(pkey_pm->pkey);
pkey_pm->pkey = NULL;
no_mem:
return -1;
}
void ssl_pm_set_bufflen(SSL *ssl, int len)
{
max_content_len = len;
}
long ssl_pm_get_verify_result(const SSL *ssl)
{
uint32_t ret;
long verify_result;
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
ret = mbedtls_ssl_get_verify_result(&ssl_pm->ssl);
if (ret) {
SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "mbedtls_ssl_get_verify_result() return 0x%x", ret);
verify_result = X509_V_ERR_UNSPECIFIED;
} else
verify_result = X509_V_OK;
return verify_result;
}
/**
* @brief set expected hostname on peer cert CN
*/
int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param,
const char *name, size_t namelen)
{
SSL *ssl = (SSL *)((char *)param - offsetof(SSL, param));
struct ssl_pm *ssl_pm = (struct ssl_pm *)ssl->ssl_pm;
char *name_cstr = NULL;
if (namelen) {
name_cstr = malloc(namelen + 1);
if (!name_cstr) {
return 0;
}
memcpy(name_cstr, name, namelen);
name_cstr[namelen] = '\0';
name = name_cstr;
}
mbedtls_ssl_set_hostname(&ssl_pm->ssl, name);
if (namelen) {
free(name_cstr);
}
return 1;
}