esp-idf/components/wpa_supplicant/esp_supplicant/src/crypto/tls_mbedtls.c

1226 wiersze
35 KiB
C

/*
* SPDX-FileCopyrightText: 2020-2024 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "utils/includes.h"
#include "utils/common.h"
#include "crypto/tls.h"
#include "crypto/sha1.h"
#include "crypto/md5.h"
#include "crypto/sha256.h"
#include "crypto/sha384.h"
/* TODO: Remove this once the appropriate solution is found
*
* ssl_misc.h header uses private elements from
* mbedtls, which become undefined if the following flag
* is not defined
*/
#define MBEDTLS_ALLOW_PRIVATE_ACCESS
// located at mbedtls/library/ssl_misc.h
#include "ssl_misc.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/entropy.h"
#include "mbedtls/debug.h"
#include "mbedtls/oid.h"
#ifdef ESPRESSIF_USE
#include "mbedtls/esp_debug.h"
#include "mbedtls/esp_config.h"
#else
#include "mbedtls/config.h"
#endif
#include "mbedtls/platform.h"
#include "eap_peer/eap.h"
#ifdef CONFIG_TLSV13
#include "psa/crypto.h"
#include "md_psa.h"
#include "ssl_tls13_keys.h"
#define PSA_TO_MBEDTLS_ERR(status) PSA_TO_MBEDTLS_ERR_LIST(status, \
psa_to_ssl_errors, \
psa_generic_status_to_mbedtls)
#endif /* CONFIG_TLSV13 */
#define TLS_RANDOM_LEN 32
#define TLS_HASH_MAX_SIZE 64
#define TLS_MASTER_SECRET_LEN 48
#define MAX_CIPHERSUITE 32
#define MAX_EXPORTER_CONTEXT_LEN 65535
/* Throw a compilation error if basic requirements in mbedtls are not enabled */
#if !defined(MBEDTLS_SSL_TLS_C)
#error "TLS not enabled in mbedtls config"
#endif
#if !defined(MBEDTLS_SHA256_C)
#error "SHA256 is disabled in mbedtls config"
#endif
#if !defined(MBEDTLS_AES_C)
#error "AES support is disabled in mbedtls config"
#endif
uint32_t tls_instance_count;
struct tls_data {
/* Data for mbedlts */
struct wpabuf *in_data;
/* Data from mbedtls */
struct wpabuf *out_data;
};
typedef struct tls_context {
mbedtls_ssl_context ssl; /*!< TLS/SSL context */
mbedtls_entropy_context entropy; /*!< mbedTLS entropy context structure */
mbedtls_ctr_drbg_context ctr_drbg; /*!< mbedTLS ctr drbg context structure */
mbedtls_ssl_config conf; /*!< TLS/SSL config to be shared structures */
mbedtls_x509_crt cacert; /*!< Container for X.509 CA certificate */
mbedtls_x509_crt *cacert_ptr; /*!< Pointer to the cacert being used. */
mbedtls_x509_crt clientcert; /*!< Container for X.509 client certificate */
mbedtls_pk_context clientkey; /*!< Private key of client certificate */
int ciphersuite[MAX_CIPHERSUITE];
} tls_context_t;
struct tls_connection {
tls_context_t *tls;
struct tls_data tls_io_data;
unsigned char master_secret[TLS_MASTER_SECRET_LEN];
unsigned char randbytes[2 * TLS_RANDOM_LEN];
mbedtls_tls_prf_types tls_prf_type;
#ifdef CONFIG_TLSV13
unsigned char exporter_master_secret[TLS_HASH_MAX_SIZE];
#endif /* CONFIG_TLSV13 */
};
static void tls_mbedtls_cleanup(tls_context_t *tls)
{
if (!tls) {
return;
}
tls->cacert_ptr = NULL;
mbedtls_x509_crt_free(&tls->cacert);
mbedtls_x509_crt_free(&tls->clientcert);
mbedtls_pk_free(&tls->clientkey);
mbedtls_entropy_free(&tls->entropy);
mbedtls_ssl_config_free(&tls->conf);
mbedtls_ctr_drbg_free(&tls->ctr_drbg);
mbedtls_ssl_free(&tls->ssl);
}
static void tls_mbedtls_conn_delete(tls_context_t *tls)
{
if (tls != NULL) {
tls_mbedtls_cleanup(tls);
}
}
static int tls_mbedtls_write(void *ctx, const unsigned char *buf, size_t len)
{
struct tls_connection *conn = (struct tls_connection *)ctx;
struct tls_data *data = &conn->tls_io_data;
if (wpabuf_resize(&data->out_data, len) < 0)
return 0;
wpabuf_put_data(data->out_data, buf, len);
return len;
}
static int tls_mbedtls_read(void *ctx, unsigned char *buf, size_t len)
{
struct tls_connection *conn = (struct tls_connection *)ctx;
struct tls_data *data = &conn->tls_io_data;
struct wpabuf *local_buf;
if (data->in_data == NULL || len > wpabuf_len(data->in_data)) {
/* We don't have suffient buffer available for read */
wpa_printf(MSG_INFO, "len=%zu not available in input", len);
return MBEDTLS_ERR_SSL_WANT_READ;
}
os_memcpy(buf, wpabuf_head(data->in_data), len);
/* adjust buffer */
if (len < wpabuf_len(data->in_data)) {
/* TODO optimize this operation */
local_buf = wpabuf_alloc_copy(wpabuf_mhead_u8(data->in_data) + len,
wpabuf_len(data->in_data) - len);
wpabuf_free(data->in_data);
data->in_data = local_buf;
} else {
wpabuf_free(data->in_data);
data->in_data = NULL;
}
return len;
}
static int set_pki_context(tls_context_t *tls, const struct tls_connection_params *cfg)
{
int ret;
if (cfg->client_cert_blob == NULL || cfg->private_key_blob == NULL) {
wpa_printf(MSG_ERROR, "%s: config not correct", __func__);
return -1;
}
mbedtls_x509_crt_init(&tls->clientcert);
mbedtls_pk_init(&tls->clientkey);
ret = mbedtls_x509_crt_parse(&tls->clientcert,
cfg->client_cert_blob, cfg->client_cert_blob_len);
if (ret < 0) {
wpa_printf(MSG_ERROR, "mbedtls_x509_crt_parse returned -0x%x", -ret);
return ret;
}
ret = mbedtls_pk_parse_key(&tls->clientkey, cfg->private_key_blob, cfg->private_key_blob_len,
(const unsigned char *)cfg->private_key_passwd,
cfg->private_key_passwd ? os_strlen(cfg->private_key_passwd) : 0, mbedtls_ctr_drbg_random, &tls->ctr_drbg);
if (ret < 0) {
wpa_printf(MSG_ERROR, "mbedtls_pk_parse_keyfile returned -0x%x", -ret);
return ret;
}
ret = mbedtls_ssl_conf_own_cert(&tls->conf, &tls->clientcert, &tls->clientkey);
if (ret < 0) {
wpa_printf(MSG_ERROR, "mbedtls_ssl_conf_own_cert returned -0x%x", -ret);
return ret;
}
return 0;
}
static int set_ca_cert(tls_context_t *tls, const unsigned char *cacert, size_t cacert_len)
{
tls->cacert_ptr = &tls->cacert;
mbedtls_x509_crt_init(tls->cacert_ptr);
int ret = mbedtls_x509_crt_parse(tls->cacert_ptr, cacert, cacert_len);
if (ret < 0) {
wpa_printf(MSG_ERROR, "mbedtls_x509_crt_parse returned -0x%x", -ret);
return ret;
}
mbedtls_ssl_conf_authmode(&tls->conf, MBEDTLS_SSL_VERIFY_REQUIRED);
mbedtls_ssl_conf_ca_chain(&tls->conf, tls->cacert_ptr, NULL);
return 0;
}
#ifdef CONFIG_SUITEB192
static uint16_t tls_sig_algs_for_suiteb[] = {
#ifdef CONFIG_TLSV13
#if defined(MBEDTLS_KEY_EXCHANGE_ECDSA_CERT_REQ_ANY_ALLOWED_ENABLED) && \
defined(MBEDTLS_MD_CAN_SHA384) && \
defined(PSA_WANT_ECC_SECP_R1_384)
MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384,
// == MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG(MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA384)
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECDSA_CERT_REQ_ANY_ALLOWED_ENABLED) && \
defined(MBEDTLS_MD_CAN_SHA512) && \
defined(PSA_WANT_ECC_SECP_R1_521)
MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512,
// == MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG(MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA512)
#endif
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT) && \
defined(MBEDTLS_MD_CAN_SHA512)
MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512,
#endif \
/* MBEDTLS_X509_RSASSA_PSS_SUPPORT && MBEDTLS_MD_CAN_SHA512 */
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT) && \
defined(MBEDTLS_MD_CAN_SHA384)
MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384,
#endif \
/* MBEDTLS_X509_RSASSA_PSS_SUPPORT && MBEDTLS_MD_CAN_SHA384 */
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_MD_CAN_SHA512)
MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA512,
#endif /* MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA512 */
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_MD_CAN_SHA384)
MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA384,
#endif /* MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA384 */
#endif /* CONFIG_TLSV13 */
#if defined(MBEDTLS_SHA512_C)
#if defined(MBEDTLS_ECDSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA512 ),
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA384 ),
#endif
#if defined(MBEDTLS_RSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_RSA, MBEDTLS_SSL_HASH_SHA512 ),
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_RSA, MBEDTLS_SSL_HASH_SHA384 ),
#endif
#endif /* MBEDTLS_SHA512_C */
MBEDTLS_TLS_SIG_NONE
};
const mbedtls_x509_crt_profile suiteb_mbedtls_x509_crt_profile =
{
#if defined(MBEDTLS_SHA512_C)
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ) |
#endif
0,
0xFFFFFFF, /* Any PK alg */
MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP384R1),
1024,
};
static void tls_set_suiteb_config(tls_context_t *tls)
{
const mbedtls_x509_crt_profile *crt_profile = &suiteb_mbedtls_x509_crt_profile;
mbedtls_ssl_conf_cert_profile(&tls->conf, crt_profile);
mbedtls_ssl_conf_sig_algs(&tls->conf, tls_sig_algs_for_suiteb);
}
#endif
static uint16_t tls_sig_algs_for_eap[] = {
#ifdef CONFIG_TLSV13
#if defined(MBEDTLS_KEY_EXCHANGE_ECDSA_CERT_REQ_ANY_ALLOWED_ENABLED) && \
defined(MBEDTLS_MD_CAN_SHA256) && \
defined(PSA_WANT_ECC_SECP_R1_256)
MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256,
// == MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG(MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA256)
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECDSA_CERT_REQ_ANY_ALLOWED_ENABLED) && \
defined(MBEDTLS_MD_CAN_SHA384) && \
defined(PSA_WANT_ECC_SECP_R1_384)
MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384,
// == MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG(MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA384)
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECDSA_CERT_REQ_ANY_ALLOWED_ENABLED) && \
defined(MBEDTLS_MD_CAN_SHA512) && \
defined(PSA_WANT_ECC_SECP_R1_521)
MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512,
// == MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG(MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA512)
#endif
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT) && \
defined(MBEDTLS_MD_CAN_SHA512)
MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512,
#endif \
/* MBEDTLS_X509_RSASSA_PSS_SUPPORT && MBEDTLS_MD_CAN_SHA512 */
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT) && \
defined(MBEDTLS_MD_CAN_SHA384)
MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384,
#endif \
/* MBEDTLS_X509_RSASSA_PSS_SUPPORT && MBEDTLS_MD_CAN_SHA384 */
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT) && \
defined(MBEDTLS_MD_CAN_SHA256)
MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256,
#endif \
/* MBEDTLS_X509_RSASSA_PSS_SUPPORT && MBEDTLS_MD_CAN_SHA256 */
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_MD_CAN_SHA512)
MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA512,
#endif /* MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA512 */
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_MD_CAN_SHA384)
MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA384,
#endif /* MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA384 */
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_MD_CAN_SHA256)
MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA256,
#endif /* MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA256 */
#endif /* CONFIG_TLSV13 */
#if defined(MBEDTLS_SHA512_C)
#if defined(MBEDTLS_ECDSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA512 ),
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA384 ),
#endif
#if defined(MBEDTLS_RSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_RSA, MBEDTLS_SSL_HASH_SHA512 ),
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_RSA, MBEDTLS_SSL_HASH_SHA384 ),
#endif
#endif /* MBEDTLS_SHA512_C */
#if defined(MBEDTLS_SHA256_C)
#if defined(MBEDTLS_ECDSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA256 ),
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA224 ),
#endif
#if defined(MBEDTLS_RSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_RSA, MBEDTLS_SSL_HASH_SHA256 ),
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_RSA, MBEDTLS_SSL_HASH_SHA224 ),
#endif
#endif /* MBEDTLS_SHA256_C */
#if defined(MBEDTLS_SHA1_C)
#if defined(MBEDTLS_ECDSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_ECDSA, MBEDTLS_SSL_HASH_SHA1 ),
#endif
#if defined(MBEDTLS_RSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG( MBEDTLS_SSL_SIG_RSA, MBEDTLS_SSL_HASH_SHA1 ),
#endif
#endif /* MBEDTLS_SHA1_C */
MBEDTLS_TLS_SIG_NONE
};
const mbedtls_x509_crt_profile eap_mbedtls_x509_crt_profile =
{
#if defined(MBEDTLS_SHA1_C)
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA1 ) |
#endif
#if defined(MBEDTLS_SHA256_C)
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA224 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
#endif
#if defined(MBEDTLS_SHA512_C)
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ) |
#endif
0,
0xFFFFFFF, /* Any PK alg */
0xFFFFFFF, /* Any curve */
1024,
};
static void tls_enable_sha1_config(tls_context_t *tls)
{
const mbedtls_x509_crt_profile *crt_profile = &eap_mbedtls_x509_crt_profile;
mbedtls_ssl_conf_cert_profile(&tls->conf, crt_profile);
mbedtls_ssl_conf_sig_algs(&tls->conf, tls_sig_algs_for_eap);
}
#ifdef CONFIG_ESP_WIFI_DISABLE_KEY_USAGE_CHECK
static int tls_disable_key_usages(void *data, mbedtls_x509_crt *cert, int depth, uint32_t *flags)
{
cert->MBEDTLS_PRIVATE(ext_types) &= ~MBEDTLS_X509_EXT_KEY_USAGE;
cert->MBEDTLS_PRIVATE(ext_types) &= ~MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE;
return 0;
}
#endif /*CONFIG_ESP_WIFI_DISABLE_KEY_USAGE_CHECK*/
#ifdef CONFIG_SUITEB192
static const int suiteb_rsa_ciphersuite_preference[] =
{
#if defined(CONFIG_ESP_WIFI_EAP_TLS1_3)
MBEDTLS_TLS1_3_AES_256_GCM_SHA384,
#endif /* CONFIG_ESP_WIFI_EAP_TLS1_3 */
#if defined(MBEDTLS_GCM_C)
#if defined(MBEDTLS_SHA512_C)
MBEDTLS_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
MBEDTLS_TLS_DHE_RSA_WITH_AES_256_GCM_SHA384,
#endif
#endif
0
};
static const int suiteb_ecc_ciphersuite_preference[] =
{
#if defined(CONFIG_ESP_WIFI_EAP_TLS1_3)
MBEDTLS_TLS1_3_AES_256_GCM_SHA384,
#endif /* CONFIG_ESP_WIFI_EAP_TLS1_3 */
#if defined(MBEDTLS_GCM_C)
#if defined(MBEDTLS_SHA512_C)
MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
#endif
#endif
0
};
static const int suiteb_ciphersuite_preference[] =
{
#if defined(CONFIG_ESP_WIFI_EAP_TLS1_3)
MBEDTLS_TLS1_3_AES_256_GCM_SHA384,
#endif /* CONFIG_ESP_WIFI_EAP_TLS1_3 */
#if defined(MBEDTLS_GCM_C)
#if defined(MBEDTLS_SHA512_C)
MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
MBEDTLS_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
MBEDTLS_TLS_DHE_RSA_WITH_AES_256_GCM_SHA384,
#endif
#endif
0
};
#endif
static void tls_set_ciphersuite(const struct tls_connection_params *cfg, tls_context_t *tls)
{
/* Only set ciphersuite if cert's key length is high or ciphersuites are set by user */
#ifdef CONFIG_SUITEB192
if (cfg->flags & TLS_CONN_SUITEB) {
/* cipher suites will be set based on certificate */
mbedtls_pk_type_t pk_alg = mbedtls_pk_get_type(&tls->clientkey);
if (pk_alg == MBEDTLS_PK_RSA || pk_alg == MBEDTLS_PK_RSASSA_PSS) {
mbedtls_ssl_conf_ciphersuites(&tls->conf,
suiteb_rsa_ciphersuite_preference);
} else if (pk_alg == MBEDTLS_PK_ECDSA ||
pk_alg == MBEDTLS_PK_ECKEY ||
pk_alg == MBEDTLS_PK_ECKEY_DH) {
mbedtls_ssl_conf_ciphersuites(&tls->conf,
suiteb_ecc_ciphersuite_preference);
} else {
mbedtls_ssl_conf_ciphersuites(&tls->conf,
suiteb_ciphersuite_preference);
}
} else
#endif
/* Set cipher suites if User has explicitly set those
* TODO: public API to set EAP ciphers */
if (tls->ciphersuite[0]) {
mbedtls_ssl_conf_ciphersuites(&tls->conf, tls->ciphersuite);
}
}
static int set_client_config(const struct tls_connection_params *cfg, tls_context_t *tls)
{
int ret;
int preset = MBEDTLS_SSL_PRESET_DEFAULT;
assert(cfg != NULL);
assert(tls != NULL);
#ifdef CONFIG_SUITEB192
if (cfg->flags & TLS_CONN_SUITEB)
preset = MBEDTLS_SSL_PRESET_SUITEB;
#endif
ret = mbedtls_ssl_config_defaults(&tls->conf,
MBEDTLS_SSL_IS_CLIENT,
MBEDTLS_SSL_TRANSPORT_STREAM,
preset);
if (ret != 0) {
wpa_printf(MSG_ERROR, "mbedtls_ssl_config_defaults returned -0x%x", -ret);
return ret;
}
if (preset != MBEDTLS_SSL_PRESET_SUITEB) {
/* Enable SHA1 support since it's not enabled by default in mbedtls */
tls_enable_sha1_config(tls);
#ifdef CONFIG_SUITEB192
} else {
tls_set_suiteb_config(tls);
#endif
}
if (cfg->ca_cert_blob != NULL) {
ret = set_ca_cert(tls, cfg->ca_cert_blob, cfg->ca_cert_blob_len);
if (ret != 0) {
return ret;
}
} else {
mbedtls_ssl_conf_authmode(&tls->conf, MBEDTLS_SSL_VERIFY_NONE);
}
if (cfg->client_cert_blob != NULL && cfg->private_key_blob != NULL) {
ret = set_pki_context(tls, cfg);
if (ret != 0) {
wpa_printf(MSG_ERROR, "Failed to set client pki context");
return ret;
}
}
/* Usages of default ciphersuites can take a lot of time on low end device
* and can cause watchdog. Enabling the ciphers which are secured enough
* but doesn't take that much processing power */
tls_set_ciphersuite(cfg, tls);
#ifdef CONFIG_ESP_WIFI_DISABLE_KEY_USAGE_CHECK
mbedtls_ssl_set_verify( &tls->ssl, tls_disable_key_usages, NULL );
#endif /*CONFIG_ESP_WIFI_DISABLE_KEY_USAGE_CHECK*/
#ifdef CONFIG_MBEDTLS_CERTIFICATE_BUNDLE
if (cfg->flags & TLS_CONN_USE_DEFAULT_CERT_BUNDLE) {
wpa_printf(MSG_INFO, "Using default cert bundle");
if (esp_crt_bundle_attach_fn) {
ret = (*esp_crt_bundle_attach_fn)(&tls->conf);
}
if (ret != 0) {
wpa_printf(MSG_ERROR, "Failed to set default cert bundle");
return ret;
}
}
#endif
return 0;
}
#ifdef CONFIG_TLSV13
static void tls13_extract_exporter_master_secret(struct tls_connection *conn)
{
mbedtls_ssl_context *ssl = &conn->tls->ssl;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info;
psa_algorithm_t hash_alg = mbedtls_md_psa_alg_from_type(ciphersuite_info->mac);
size_t hash_len = PSA_HASH_LENGTH(hash_alg);
assert(hash_len != 0);
mbedtls_ssl_tls13_application_secrets *app_secrets =
&ssl->session_negotiate->app_secrets;
os_memcpy(conn->exporter_master_secret, app_secrets->exporter_master_secret, hash_len);
}
#endif /* CONFIG_TLSV13 */
static void tls_key_derivation(void *ctx,
mbedtls_ssl_key_export_type secret_type,
const unsigned char *secret,
size_t secret_len,
const unsigned char client_random[TLS_RANDOM_LEN],
const unsigned char server_random[TLS_RANDOM_LEN],
mbedtls_tls_prf_types tls_prf_type)
{
struct tls_connection *conn = (struct tls_connection *)ctx;
os_memcpy(conn->master_secret, secret, sizeof(conn->master_secret));
os_memcpy(conn->randbytes, client_random, TLS_RANDOM_LEN);
os_memcpy(conn->randbytes + 32, server_random, TLS_RANDOM_LEN);
conn->tls_prf_type = tls_prf_type;
#ifdef CONFIG_TLSV13
if (secret_type == MBEDTLS_SSL_KEY_EXPORT_TLS1_3_SERVER_APPLICATION_TRAFFIC_SECRET) {
tls13_extract_exporter_master_secret(conn);
}
#endif /* CONFIG_TLSV13 */
}
static int tls_create_mbedtls_handle(struct tls_connection *conn,
const struct tls_connection_params *params,
tls_context_t *tls)
{
int ret;
assert(params != NULL);
assert(tls != NULL);
mbedtls_ssl_init(&tls->ssl);
mbedtls_ctr_drbg_init(&tls->ctr_drbg);
mbedtls_ssl_config_init(&tls->conf);
mbedtls_entropy_init(&tls->entropy);
ret = set_client_config(params, tls);
if (ret != 0) {
wpa_printf(MSG_ERROR, "Failed to set client configurations");
goto exit;
}
ret = mbedtls_ctr_drbg_seed(&tls->ctr_drbg, mbedtls_entropy_func,
&tls->entropy, NULL, 0);
if (ret != 0) {
wpa_printf(MSG_ERROR, "mbedtls_ctr_drbg_seed returned -0x%x", -ret);
goto exit;
}
mbedtls_ssl_conf_rng(&tls->conf, mbedtls_ctr_drbg_random, &tls->ctr_drbg);
#if defined(CONFIG_MBEDTLS_SSL_PROTO_TLS1_3) && !defined(CONFIG_TLSV13)
/* Disable TLSv1.3 even when enabled in MbedTLS and not enabled in WiFi config.
* TODO: Remove Kconfig option for TLSv1.3 when it is matured enough */
mbedtls_ssl_conf_max_tls_version(&tls->conf, MBEDTLS_SSL_VERSION_TLS1_2);
#endif /* CONFIG_MBEDTLS_SSL_PROTO_TLS1_3 && !CONFIG_TLSV13 */
ret = mbedtls_ssl_setup(&tls->ssl, &tls->conf);
if (ret != 0) {
wpa_printf(MSG_ERROR, "mbedtls_ssl_setup returned -0x%x", -ret);
goto exit;
}
mbedtls_ssl_set_export_keys_cb(&tls->ssl, tls_key_derivation, conn);
#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
/* Disable BEAST attack countermeasures for Windows 2008 interoperability */
mbedtls_ssl_conf_cbc_record_splitting(&tls->conf, MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED);
#endif
/* Enable debug prints in case supplicant's prints are enabled */
#if defined(CONFIG_MBEDTLS_DEBUG) && defined(ESPRESSIF_USE)
mbedtls_esp_enable_debug_log(&tls->conf, 2);
#endif
return 0;
exit:
tls_mbedtls_cleanup(tls);
return ret;
}
void *tls_init(const struct tls_config *conf)
{
tls_instance_count++;
return &tls_instance_count;
}
void tls_deinit(void *tls_ctx)
{
tls_instance_count--;
}
struct tls_connection * tls_connection_init(void *tls_ctx)
{
struct tls_connection *conn = os_zalloc(sizeof(*conn));
if (!conn) {
wpa_printf(MSG_ERROR, "TLS: Failed to allocate connection memory");
return NULL;
}
#ifdef CONFIG_TLSV13
psa_status_t status = psa_crypto_init();
if (status != PSA_SUCCESS) {
wpa_printf(MSG_ERROR, "Failed to initialize PSA crypto, returned %d", (int) status);
return NULL;
}
#endif /* CONFIG_TLSV13 */
return conn;
}
void tls_connection_deinit(void *tls_ctx, struct tls_connection *conn)
{
/* case: tls init failed */
if (!conn) {
return;
}
/* Free ssl ctx and data */
tls_mbedtls_conn_delete((tls_context_t *) conn->tls);
os_free(conn->tls);
conn->tls = NULL;
/* Data in in ssl ctx, free connection */
os_free(conn);
}
int tls_get_errors(void *tls_ctx)
{
return 0;
}
int tls_connection_established(void *tls_ctx, struct tls_connection *conn)
{
mbedtls_ssl_context *ssl = &conn->tls->ssl;
return mbedtls_ssl_is_handshake_over(ssl);
}
int tls_global_set_verify(void *tls_ctx, int check_crl, int strict)
{
wpa_printf(MSG_INFO, "TLS: global settings are not supported");
return -1;
}
int tls_connection_set_verify(void *tls_ctx, struct tls_connection *conn,
int verify_peer, unsigned int flags,
const u8 *session_ctx, size_t session_ctx_len)
{
wpa_printf(MSG_INFO, "TLS: tls_connection_set_verify not supported");
return -1;
}
#ifdef CONFIG_ESP_WIFI_ENT_FREE_DYNAMIC_BUFFER
static void esp_mbedtls_free_dhm(mbedtls_ssl_context *ssl)
{
#ifdef CONFIG_MBEDTLS_DHM_C
const mbedtls_ssl_config *conf = mbedtls_ssl_context_get_config(ssl);
mbedtls_mpi_free((mbedtls_mpi *)&conf->MBEDTLS_PRIVATE(dhm_P));
mbedtls_mpi_free((mbedtls_mpi *)&conf->MBEDTLS_PRIVATE(dhm_G));
#endif /* CONFIG_MBEDTLS_DHM_C */
}
static void esp_mbedtls_free_keycert(mbedtls_ssl_context *ssl)
{
mbedtls_ssl_config *conf = (mbedtls_ssl_config * )mbedtls_ssl_context_get_config(ssl);
mbedtls_ssl_key_cert *keycert = conf->MBEDTLS_PRIVATE(key_cert), *next;
while (keycert) {
next = keycert->next;
if (keycert) {
mbedtls_free(keycert);
}
keycert = next;
}
conf->MBEDTLS_PRIVATE(key_cert) = NULL;
}
static void esp_mbedtls_free_keycert_key(mbedtls_ssl_context *ssl)
{
const mbedtls_ssl_config *conf = mbedtls_ssl_context_get_config(ssl);
mbedtls_ssl_key_cert *keycert = conf->MBEDTLS_PRIVATE(key_cert);
while (keycert) {
if (keycert->key) {
mbedtls_pk_free(keycert->key);
keycert->key = NULL;
}
keycert = keycert->next;
}
}
static void esp_mbedtls_free_cacert(mbedtls_ssl_context *ssl)
{
if (ssl->MBEDTLS_PRIVATE(conf)->MBEDTLS_PRIVATE(ca_chain)) {
mbedtls_ssl_config *conf = (mbedtls_ssl_config * )mbedtls_ssl_context_get_config(ssl);
mbedtls_x509_crt_free(conf->MBEDTLS_PRIVATE(ca_chain));
conf->MBEDTLS_PRIVATE(ca_chain) = NULL;
}
}
#endif
struct wpabuf * tls_connection_handshake(void *tls_ctx,
struct tls_connection *conn,
const struct wpabuf *in_data,
struct wpabuf **appl_data)
{
tls_context_t *tls = conn->tls;
int ret = 0;
struct wpabuf *resp;
/* data freed by sender */
conn->tls_io_data.out_data = NULL;
if (wpabuf_len(in_data)) {
conn->tls_io_data.in_data = wpabuf_dup(in_data);
}
/* Multiple reads */
while (!mbedtls_ssl_is_handshake_over(&tls->ssl)) {
#ifdef CONFIG_ESP_WIFI_ENT_FREE_DYNAMIC_BUFFER
int cli_state = tls->ssl.MBEDTLS_PRIVATE(state);
#endif /* CONFIG_ESP_WIFI_ENT_FREE_DYNAMIC_BUFFER */
ret = mbedtls_ssl_handshake_step(&tls->ssl);
if (ret < 0) {
break;
}
#ifdef CONFIG_ESP_WIFI_ENT_FREE_DYNAMIC_BUFFER
if (mbedtls_ssl_get_version_number(&tls->ssl) == MBEDTLS_SSL_VERSION_TLS1_2) {
if (cli_state == MBEDTLS_SSL_SERVER_CERTIFICATE) {
esp_mbedtls_free_cacert(&tls->ssl);
} else if (cli_state == MBEDTLS_SSL_CERTIFICATE_VERIFY) {
esp_mbedtls_free_dhm(&tls->ssl);
esp_mbedtls_free_keycert_key(&tls->ssl);
esp_mbedtls_free_keycert(&tls->ssl);
}
}
#endif
}
if (ret < 0 && ret != MBEDTLS_ERR_SSL_WANT_READ) {
wpa_printf(MSG_INFO, "%s: ret is %d line:%d", __func__, ret, __LINE__);
goto end;
}
if (!conn->tls_io_data.out_data) {
wpa_printf(MSG_INFO, "application data is null, adding one byte for ack");
u8 *dummy = os_zalloc(1);
if (dummy == NULL) {
wpa_printf(MSG_INFO, "%s: memory allocation failure. line:%d", __func__, __LINE__);
goto end;
}
#ifdef CONFIG_TLSV13
if (mbedtls_ssl_get_version_number(&conn->tls->ssl) == MBEDTLS_SSL_VERSION_TLS1_3) {
*appl_data = wpabuf_alloc_ext_data(dummy, 1);
if (appl_data == NULL) {
wpa_printf(MSG_INFO, "%s: memory allocation failure. line:%d", __func__, __LINE__);
os_free(dummy);
goto end;
}
return NULL;
}
#endif /* CONFIG_TLSV13 */
conn->tls_io_data.out_data = wpabuf_alloc_ext_data(dummy, 0);
if (conn->tls_io_data.out_data == NULL) {
wpa_printf(MSG_INFO, "%s: memory allocation failure. line:%d", __func__, __LINE__);
os_free(dummy);
goto end;
}
}
end:
resp = conn->tls_io_data.out_data;
conn->tls_io_data.out_data = NULL;
return resp;
}
struct wpabuf * tls_connection_server_handshake(void *tls_ctx,
struct tls_connection *conn,
const struct wpabuf *in_data,
struct wpabuf **appl_data)
{
wpa_printf(MSG_ERROR, "%s: not supported %d", __func__, __LINE__);
return NULL;
}
struct wpabuf * tls_connection_encrypt(void *tls_ctx,
struct tls_connection *conn,
const struct wpabuf *in_data)
{
struct wpabuf *resp;
size_t ret;
/* Reset dangling pointer */
conn->tls_io_data.out_data = NULL;
ret = mbedtls_ssl_write(&conn->tls->ssl,
(unsigned char*) wpabuf_head(in_data), wpabuf_len(in_data));
if (ret < wpabuf_len(in_data)) {
wpa_printf(MSG_ERROR, "%s:%d, not able to write whole data",
__func__, __LINE__);
}
resp = conn->tls_io_data.out_data;
conn->tls_io_data.out_data = NULL;
return resp;
}
struct wpabuf *tls_connection_decrypt(void *tls_ctx,
struct tls_connection *conn,
const struct wpabuf *in_data)
{
#define MAX_PHASE2_BUFFER 1536
struct wpabuf *out = NULL;
int ret;
unsigned char *buf = os_malloc(MAX_PHASE2_BUFFER);
if (!buf) {
return NULL;
}
/* Reset dangling output buffer before setting data, data was freed by caller */
conn->tls_io_data.out_data = NULL;
conn->tls_io_data.in_data = wpabuf_dup(in_data);
if (!conn->tls_io_data.in_data) {
goto cleanup;
}
ret = mbedtls_ssl_read(&conn->tls->ssl, buf, MAX_PHASE2_BUFFER);
if (ret < 0) {
wpa_printf(MSG_ERROR, "%s:%d, not able to read data",
__func__, __LINE__);
goto cleanup;
}
out = wpabuf_alloc_copy(buf, ret);
cleanup:
/* there may be some error written in output buffer */
if (conn->tls_io_data.out_data) {
os_free(conn->tls_io_data.out_data);
conn->tls_io_data.out_data = NULL;
}
os_free(buf);
return out;
#undef MAX_PHASE2_BUFFER
}
int tls_connection_resumed(void *tls_ctx, struct tls_connection *conn)
{
if (conn && conn->tls && conn->tls->ssl.MBEDTLS_PRIVATE(handshake)) {
return conn->tls->ssl.MBEDTLS_PRIVATE(handshake)->resume;
}
return 0;
}
/* cipher array should contain cipher number in mbedtls num as per IANA
* Please see cipherlist is u8, therefore only initial ones are supported */
int tls_connection_set_cipher_list(void *tls_ctx, struct tls_connection *conn,
u8 *ciphers)
{
int i = 0;
while (*ciphers != 0 && i < MAX_CIPHERSUITE) {
conn->tls->ciphersuite[i] = ciphers[i];
i++;
}
return 0;
}
int tls_get_version(void *tls_ctx, struct tls_connection *conn,
char *buf, size_t buflen)
{
const char *name;
if (conn == NULL) {
return -1;
}
name = mbedtls_ssl_get_version(&conn->tls->ssl);
if (name == NULL) {
return -1;
}
os_strlcpy(buf, name, buflen);
return 0;
}
int tls_get_cipher(void *tls_ctx, struct tls_connection *conn,
char *buf, size_t buflen)
{
const char *name;
if (conn == NULL) {
return -1;
}
name = mbedtls_ssl_get_ciphersuite(&conn->tls->ssl);
if (name == NULL) {
return -1;
}
os_strlcpy(buf, name, buflen);
return 0;
}
int tls_connection_enable_workaround(void *tls_ctx,
struct tls_connection *conn)
{
wpa_printf(MSG_ERROR, "%s: not supported %d", __func__, __LINE__);
return -1;
}
int tls_connection_get_failed(void *tls_ctx, struct tls_connection *conn)
{
return 0;
}
int tls_connection_get_read_alerts(void *tls_ctx, struct tls_connection *conn)
{
wpa_printf(MSG_ERROR, "%s: not supported %d", __func__, __LINE__);
return 0;
}
int tls_connection_get_write_alerts(void *tls_ctx, struct tls_connection *conn)
{
wpa_printf(MSG_ERROR, "%s: not supported %d", __func__, __LINE__);
return 0;
}
int tls_connection_set_params(void *tls_ctx, struct tls_connection *conn,
const struct tls_connection_params *params)
{
int ret = 0;
tls_context_t *tls = (tls_context_t *)os_zalloc(sizeof(tls_context_t));
if (!tls) {
wpa_printf(MSG_ERROR, "failed to allocate tls context");
return -1;
}
if (!params) {
wpa_printf(MSG_ERROR, "configuration is null");
ret = -1;
goto err;
}
ret = tls_create_mbedtls_handle(conn, params, tls);
if (ret < 0) {
wpa_printf(MSG_ERROR, "failed to create ssl handle");
goto err;
}
mbedtls_ssl_set_bio(&tls->ssl, conn, tls_mbedtls_write, tls_mbedtls_read, NULL);
conn->tls = (tls_context_t *)tls;
return ret;
err:
os_free(tls);
return ret;
}
int tls_global_set_params(void *tls_ctx,
const struct tls_connection_params *params)
{
wpa_printf(MSG_INFO, "TLS: Global parameters not supported");
return -1;
}
int tls_connection_set_session_ticket_cb(void *tls_ctx,
struct tls_connection *conn,
tls_session_ticket_cb cb,
void *ctx)
{
wpa_printf(MSG_ERROR, "TLS: %s not supported", __func__);
return -1;
}
static int tls_connection_prf(void *tls_ctx, struct tls_connection *conn,
const char *label, const u8 *context,
size_t context_len, int server_random_first,
u8 *out, size_t out_len)
{
int ret;
u8 *seed, *pos;
size_t seed_len = 2 * TLS_RANDOM_LEN;
mbedtls_ssl_context *ssl = &conn->tls->ssl;
if (context_len > MAX_EXPORTER_CONTEXT_LEN) {
return -1;
}
if (context) {
// The magic value 2 represents the memory required to store the context length.
seed_len += 2 + context_len;
}
if (!ssl) {
wpa_printf(MSG_ERROR, "TLS: %s, session ingo is null", __func__);
return -1;
}
if (!mbedtls_ssl_is_handshake_over(ssl)) {
wpa_printf(MSG_ERROR, "TLS: %s, incorrect tls state=%d", __func__, ssl->MBEDTLS_PRIVATE(state));
return -1;
}
seed = os_malloc(seed_len);
if (!seed) {
return -1;
}
if (server_random_first) {
os_memcpy(seed, conn->randbytes + TLS_RANDOM_LEN, TLS_RANDOM_LEN);
os_memcpy(seed + TLS_RANDOM_LEN, conn->randbytes, TLS_RANDOM_LEN);
} else {
os_memcpy(seed, conn->randbytes, 2 * TLS_RANDOM_LEN);
}
if (context) {
pos = seed + 2 * TLS_RANDOM_LEN;
WPA_PUT_BE16(pos, context_len);
pos += 2;
os_memcpy(pos, context, context_len);
}
wpa_hexdump_key(MSG_MSGDUMP, "random", seed, 2 * TLS_RANDOM_LEN);
wpa_hexdump_key(MSG_MSGDUMP, "master", ssl->MBEDTLS_PRIVATE(session)->MBEDTLS_PRIVATE(master), TLS_MASTER_SECRET_LEN);
ret = mbedtls_ssl_tls_prf(conn->tls_prf_type, conn->master_secret, TLS_MASTER_SECRET_LEN,
label, seed, seed_len, out, out_len);
os_free(seed);
if (ret < 0) {
wpa_printf(MSG_ERROR, "prf failed, ret=%d", ret);
return -1;
}
wpa_hexdump_key(MSG_MSGDUMP, "key", out, out_len);
return ret;
}
#ifdef CONFIG_TLSV13
/* RFC 8446 Section 7.5 */
static int tls13_connection_export_key(void *tls_ctx, struct tls_connection *conn,
const char *label, const u8 *context,
size_t context_len, u8 *out, size_t out_len)
{
int ret;
mbedtls_ssl_context *ssl = &conn->tls->ssl;
psa_algorithm_t hash_alg;
size_t hash_len;
unsigned char tmp_secret[PSA_MAC_MAX_SIZE] = { 0 };
unsigned char hashed_context[PSA_HASH_MAX_SIZE] = { 0 };
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info;
hash_alg = mbedtls_md_psa_alg_from_type(ciphersuite_info->mac);
hash_len = PSA_HASH_LENGTH(hash_alg);
ret = mbedtls_ssl_tls13_derive_secret(hash_alg,
conn->exporter_master_secret, hash_len,
(unsigned char const *) label, (size_t) strlen(label),
NULL, 0,
MBEDTLS_SSL_TLS1_3_CONTEXT_UNHASHED,
tmp_secret, hash_len);
if (ret != 0) {
wpa_printf(MSG_ERROR, "%s(): mbedtls_ssl_tls13_derive_secret() failed",
__func__);
return ret;
}
status = psa_hash_compute(hash_alg, context, context_len, hashed_context,
PSA_HASH_LENGTH(hash_alg), &context_len);
if (status != PSA_SUCCESS) {
wpa_printf(MSG_ERROR, "%s(): psa_hash_compute() failed",
__func__);
ret = PSA_TO_MBEDTLS_ERR(status);
return ret;
}
ret = mbedtls_ssl_tls13_hkdf_expand_label(hash_alg,
tmp_secret, hash_len,
MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(exporter),
hashed_context, context_len,
out, out_len);
if (ret != 0) {
wpa_printf(MSG_ERROR, "%s(): psa_hash_compute() failed",
__func__);
return ret;
}
return 0;
}
#endif /* CONFIG_TLSV13 */
int tls_connection_export_key(void *tls_ctx, struct tls_connection *conn,
const char *label, const u8 *context,
size_t context_len, u8 *out, size_t out_len)
{
#ifdef CONFIG_TLSV13
if (mbedtls_ssl_get_version_number(&conn->tls->ssl) == MBEDTLS_SSL_VERSION_TLS1_3)
return tls13_connection_export_key(tls_ctx, conn, label, context, context_len,
out, out_len);
#endif /* CONFIG_TLSV13 */
return tls_connection_prf(tls_ctx, conn, label, context, context_len,
0, out, out_len);
}
int tls_connection_get_eap_fast_key(void *tls_ctx, struct tls_connection *conn,
u8 *out, size_t out_len)
{
wpa_printf(MSG_INFO, "TLS: tls_connection_get_eap_fast_key not supported, please unset mbedtls crypto and try again");
return -1;
}
int tls_connection_client_hello_ext(void *tls_ctx, struct tls_connection *conn,
int ext_type, const u8 *data,
size_t data_len)
{
wpa_printf(MSG_INFO, "TLS: tls_connection_client_hello_ext not supported, please unset mbedtls crypto and try again");
return -1;
}
int tls_connection_shutdown(void *tls_ctx, struct tls_connection *conn)
{
if (conn->tls_io_data.in_data) {
wpabuf_free(conn->tls_io_data.in_data);
}
conn->tls_io_data.in_data = NULL;
/* outdata may have dangling pointer */
conn->tls_io_data.out_data = NULL;
return mbedtls_ssl_session_reset(&conn->tls->ssl);
}
int tls_connection_get_random(void *tls_ctx, struct tls_connection *conn,
struct tls_random *data)
{
mbedtls_ssl_context *ssl = &conn->tls->ssl;
os_memset(data, 0, sizeof(*data));
if (ssl->MBEDTLS_PRIVATE(state) == MBEDTLS_SSL_CLIENT_HELLO) {
return -1;
}
data->client_random = conn->randbytes;
data->client_random_len = TLS_RANDOM_LEN;
if (ssl->MBEDTLS_PRIVATE(state) != MBEDTLS_SSL_SERVER_HELLO) {
data->server_random = conn->randbytes + TLS_RANDOM_LEN;
data->server_random_len = TLS_RANDOM_LEN;
}
return 0;
}