esp-idf/components/aws_iot/port/network_mbedtls_wrapper.c

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/*
* Copyright 2010-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
* Additions Copyright 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.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 <sys/param.h>
#include <stdbool.h>
#include <string.h>
#include <timer_platform.h>
#include <network_interface.h>
#include "aws_iot_config.h"
#include "aws_iot_error.h"
#include "network_interface.h"
#include "network_platform.h"
#include "mbedtls/esp_debug.h"
#include "esp_log.h"
#include "esp_vfs.h"
static const char *TAG = "aws_iot";
/* This is the value used for ssl read timeout */
#define IOT_SSL_READ_TIMEOUT 10
/*
* This is a function to do further verification if needed on the cert received.
*
* Currently used to print debug-level information about each cert.
*/
static int _iot_tls_verify_cert(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags) {
char buf[256];
((void) data);
if (LOG_LOCAL_LEVEL >= ESP_LOG_DEBUG) {
ESP_LOGD(TAG, "Verify requested for (Depth %d):", depth);
mbedtls_x509_crt_info(buf, sizeof(buf) - 1, "", crt);
ESP_LOGD(TAG, "%s", buf);
if((*flags) == 0) {
ESP_LOGD(TAG, " This certificate has no flags");
} else {
ESP_LOGD(TAG, "Verify result:%s", buf);
}
}
return 0;
}
static void _iot_tls_set_connect_params(Network *pNetwork, const char *pRootCALocation, const char *pDeviceCertLocation,
const char *pDevicePrivateKeyLocation, const char *pDestinationURL,
uint16_t destinationPort, uint32_t timeout_ms, bool ServerVerificationFlag) {
pNetwork->tlsConnectParams.DestinationPort = destinationPort;
pNetwork->tlsConnectParams.pDestinationURL = pDestinationURL;
pNetwork->tlsConnectParams.pDeviceCertLocation = pDeviceCertLocation;
pNetwork->tlsConnectParams.pDevicePrivateKeyLocation = pDevicePrivateKeyLocation;
pNetwork->tlsConnectParams.pRootCALocation = pRootCALocation;
pNetwork->tlsConnectParams.timeout_ms = timeout_ms;
pNetwork->tlsConnectParams.ServerVerificationFlag = ServerVerificationFlag;
}
IoT_Error_t iot_tls_init(Network *pNetwork, const char *pRootCALocation, const char *pDeviceCertLocation,
const char *pDevicePrivateKeyLocation, const char *pDestinationURL,
uint16_t destinationPort, uint32_t timeout_ms, bool ServerVerificationFlag) {
_iot_tls_set_connect_params(pNetwork, pRootCALocation, pDeviceCertLocation, pDevicePrivateKeyLocation,
pDestinationURL, destinationPort, timeout_ms, ServerVerificationFlag);
pNetwork->connect = iot_tls_connect;
pNetwork->read = iot_tls_read;
pNetwork->write = iot_tls_write;
pNetwork->disconnect = iot_tls_disconnect;
pNetwork->isConnected = iot_tls_is_connected;
pNetwork->destroy = iot_tls_destroy;
pNetwork->tlsDataParams.flags = 0;
return SUCCESS;
}
IoT_Error_t iot_tls_is_connected(Network *pNetwork) {
/* Use this to add implementation which can check for physical layer disconnect */
return NETWORK_PHYSICAL_LAYER_CONNECTED;
}
IoT_Error_t iot_tls_connect(Network *pNetwork, TLSConnectParams *params) {
int ret = SUCCESS;
TLSDataParams *tlsDataParams = NULL;
char portBuffer[6];
char info_buf[256];
if(NULL == pNetwork) {
return NULL_VALUE_ERROR;
}
if(NULL != params) {
_iot_tls_set_connect_params(pNetwork, params->pRootCALocation, params->pDeviceCertLocation,
params->pDevicePrivateKeyLocation, params->pDestinationURL,
params->DestinationPort, params->timeout_ms, params->ServerVerificationFlag);
}
tlsDataParams = &(pNetwork->tlsDataParams);
mbedtls_net_init(&(tlsDataParams->server_fd));
mbedtls_ssl_init(&(tlsDataParams->ssl));
mbedtls_ssl_config_init(&(tlsDataParams->conf));
#ifdef CONFIG_MBEDTLS_DEBUG
mbedtls_esp_enable_debug_log(&(tlsDataParams->conf), 4);
#endif
mbedtls_ctr_drbg_init(&(tlsDataParams->ctr_drbg));
mbedtls_x509_crt_init(&(tlsDataParams->cacert));
mbedtls_x509_crt_init(&(tlsDataParams->clicert));
mbedtls_pk_init(&(tlsDataParams->pkey));
ESP_LOGD(TAG, "Seeding the random number generator...");
mbedtls_entropy_init(&(tlsDataParams->entropy));
if((ret = mbedtls_ctr_drbg_seed(&(tlsDataParams->ctr_drbg), mbedtls_entropy_func, &(tlsDataParams->entropy),
(const unsigned char *) TAG, strlen(TAG))) != 0) {
ESP_LOGE(TAG, "failed! mbedtls_ctr_drbg_seed returned -0x%x", -ret);
return NETWORK_MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED;
}
/* Load root CA...
Certs/keys can be paths or they can be raw data. These use a
very basic heuristic: if the cert starts with '/' then it's a
path, if it's longer than this then it's raw cert data (PEM or DER,
neither of which can start with a slash. */
if (pNetwork->tlsConnectParams.pRootCALocation[0] == '/') {
ESP_LOGD(TAG, "Loading CA root certificate from file ...");
ret = mbedtls_x509_crt_parse_file(&(tlsDataParams->cacert), pNetwork->tlsConnectParams.pRootCALocation);
} else {
ESP_LOGD(TAG, "Loading embedded CA root certificate ...");
ret = mbedtls_x509_crt_parse(&(tlsDataParams->cacert), (const unsigned char *)pNetwork->tlsConnectParams.pRootCALocation,
strlen(pNetwork->tlsConnectParams.pRootCALocation)+1);
}
if(ret < 0) {
ESP_LOGE(TAG, "failed! mbedtls_x509_crt_parse returned -0x%x while parsing root cert", -ret);
return NETWORK_X509_ROOT_CRT_PARSE_ERROR;
}
ESP_LOGD(TAG, "ok (%d skipped)", ret);
/* Load client certificate... */
if (pNetwork->tlsConnectParams.pDeviceCertLocation[0] == '/') {
ESP_LOGD(TAG, "Loading client cert from file...");
ret = mbedtls_x509_crt_parse_file(&(tlsDataParams->clicert),
pNetwork->tlsConnectParams.pDeviceCertLocation);
} else {
ESP_LOGD(TAG, "Loading embedded client certificate...");
ret = mbedtls_x509_crt_parse(&(tlsDataParams->clicert),
(const unsigned char *)pNetwork->tlsConnectParams.pDeviceCertLocation,
strlen(pNetwork->tlsConnectParams.pDeviceCertLocation)+1);
}
if(ret != 0) {
ESP_LOGE(TAG, "failed! mbedtls_x509_crt_parse returned -0x%x while parsing device cert", -ret);
return NETWORK_X509_DEVICE_CRT_PARSE_ERROR;
}
/* Parse client private key... */
if (pNetwork->tlsConnectParams.pDevicePrivateKeyLocation[0] == '/') {
ESP_LOGD(TAG, "Loading client private key from file...");
ret = mbedtls_pk_parse_keyfile(&(tlsDataParams->pkey),
pNetwork->tlsConnectParams.pDevicePrivateKeyLocation,
"");
} else {
ESP_LOGD(TAG, "Loading embedded client private key...");
ret = mbedtls_pk_parse_key(&(tlsDataParams->pkey),
(const unsigned char *)pNetwork->tlsConnectParams.pDevicePrivateKeyLocation,
strlen(pNetwork->tlsConnectParams.pDevicePrivateKeyLocation)+1,
(const unsigned char *)"", 0);
}
if(ret != 0) {
ESP_LOGE(TAG, "failed! mbedtls_pk_parse_key returned -0x%x while parsing private key", -ret);
return NETWORK_PK_PRIVATE_KEY_PARSE_ERROR;
}
/* Done parsing certs */
ESP_LOGD(TAG, "ok");
snprintf(portBuffer, 6, "%d", pNetwork->tlsConnectParams.DestinationPort);
ESP_LOGD(TAG, "Connecting to %s/%s...", pNetwork->tlsConnectParams.pDestinationURL, portBuffer);
if((ret = mbedtls_net_connect(&(tlsDataParams->server_fd), pNetwork->tlsConnectParams.pDestinationURL,
portBuffer, MBEDTLS_NET_PROTO_TCP)) != 0) {
ESP_LOGE(TAG, "failed! mbedtls_net_connect returned -0x%x", -ret);
switch(ret) {
case MBEDTLS_ERR_NET_SOCKET_FAILED:
return NETWORK_ERR_NET_SOCKET_FAILED;
case MBEDTLS_ERR_NET_UNKNOWN_HOST:
return NETWORK_ERR_NET_UNKNOWN_HOST;
case MBEDTLS_ERR_NET_CONNECT_FAILED:
default:
return NETWORK_ERR_NET_CONNECT_FAILED;
};
}
ret = mbedtls_net_set_block(&(tlsDataParams->server_fd));
if(ret != 0) {
ESP_LOGE(TAG, "failed! net_set_(non)block() returned -0x%x", -ret);
return SSL_CONNECTION_ERROR;
} ESP_LOGD(TAG, "ok");
ESP_LOGD(TAG, "Setting up the SSL/TLS structure...");
if((ret = mbedtls_ssl_config_defaults(&(tlsDataParams->conf), MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM,
MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
ESP_LOGE(TAG, "failed! mbedtls_ssl_config_defaults returned -0x%x", -ret);
return SSL_CONNECTION_ERROR;
}
mbedtls_ssl_conf_verify(&(tlsDataParams->conf), _iot_tls_verify_cert, NULL);
if(pNetwork->tlsConnectParams.ServerVerificationFlag == true) {
mbedtls_ssl_conf_authmode(&(tlsDataParams->conf), MBEDTLS_SSL_VERIFY_REQUIRED);
} else {
mbedtls_ssl_conf_authmode(&(tlsDataParams->conf), MBEDTLS_SSL_VERIFY_OPTIONAL);
}
mbedtls_ssl_conf_rng(&(tlsDataParams->conf), mbedtls_ctr_drbg_random, &(tlsDataParams->ctr_drbg));
mbedtls_ssl_conf_ca_chain(&(tlsDataParams->conf), &(tlsDataParams->cacert), NULL);
ret = mbedtls_ssl_conf_own_cert(&(tlsDataParams->conf), &(tlsDataParams->clicert), &(tlsDataParams->pkey));
if(ret != 0) {
ESP_LOGE(TAG, "failed! mbedtls_ssl_conf_own_cert returned %d", ret);
return SSL_CONNECTION_ERROR;
}
mbedtls_ssl_conf_read_timeout(&(tlsDataParams->conf), pNetwork->tlsConnectParams.timeout_ms);
#ifdef CONFIG_MBEDTLS_SSL_ALPN
/* Use the AWS IoT ALPN extension for MQTT, if port 443 is requested */
if (pNetwork->tlsConnectParams.DestinationPort == 443) {
const char *alpnProtocols[] = { "x-amzn-mqtt-ca", NULL };
if ((ret = mbedtls_ssl_conf_alpn_protocols(&(tlsDataParams->conf), alpnProtocols)) != 0) {
ESP_LOGE(TAG, "failed! mbedtls_ssl_conf_alpn_protocols returned -0x%x", -ret);
return SSL_CONNECTION_ERROR;
}
}
#endif
if((ret = mbedtls_ssl_setup(&(tlsDataParams->ssl), &(tlsDataParams->conf))) != 0) {
ESP_LOGE(TAG, "failed! mbedtls_ssl_setup returned -0x%x", -ret);
return SSL_CONNECTION_ERROR;
}
if((ret = mbedtls_ssl_set_hostname(&(tlsDataParams->ssl), pNetwork->tlsConnectParams.pDestinationURL)) != 0) {
ESP_LOGE(TAG, "failed! mbedtls_ssl_set_hostname returned %d", ret);
return SSL_CONNECTION_ERROR;
}
ESP_LOGD(TAG, "SSL state connect : %d ", tlsDataParams->ssl.state);
mbedtls_ssl_set_bio(&(tlsDataParams->ssl), &(tlsDataParams->server_fd), mbedtls_net_send, NULL,
mbedtls_net_recv_timeout);
ESP_LOGD(TAG, "ok");
ESP_LOGD(TAG, "SSL state connect : %d ", tlsDataParams->ssl.state);
ESP_LOGD(TAG, "Performing the SSL/TLS handshake...");
while((ret = mbedtls_ssl_handshake(&(tlsDataParams->ssl))) != 0) {
if(ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
ESP_LOGE(TAG, "failed! mbedtls_ssl_handshake returned -0x%x", -ret);
if(ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
ESP_LOGE(TAG, " Unable to verify the server's certificate. ");
}
return SSL_CONNECTION_ERROR;
}
}
ESP_LOGD(TAG, "ok [ Protocol is %s ] [ Ciphersuite is %s ]", mbedtls_ssl_get_version(&(tlsDataParams->ssl)),
mbedtls_ssl_get_ciphersuite(&(tlsDataParams->ssl)));
if((ret = mbedtls_ssl_get_record_expansion(&(tlsDataParams->ssl))) >= 0) {
ESP_LOGD(TAG, " [ Record expansion is %d ]", ret);
} else {
ESP_LOGD(TAG, " [ Record expansion is unknown (compression) ]");
}
ESP_LOGD(TAG, "Verifying peer X.509 certificate...");
if(pNetwork->tlsConnectParams.ServerVerificationFlag == true) {
if((tlsDataParams->flags = mbedtls_ssl_get_verify_result(&(tlsDataParams->ssl))) != 0) {
ESP_LOGE(TAG, "failed");
mbedtls_x509_crt_verify_info(info_buf, sizeof(info_buf), " ! ", tlsDataParams->flags);
ESP_LOGE(TAG, "%s", info_buf);
ret = SSL_CONNECTION_ERROR;
} else {
ESP_LOGD(TAG, "ok");
ret = SUCCESS;
}
} else {
ESP_LOGW(TAG, " Server Verification skipped");
ret = SUCCESS;
}
if(LOG_LOCAL_LEVEL >= ESP_LOG_DEBUG) {
if (mbedtls_ssl_get_peer_cert(&(tlsDataParams->ssl)) != NULL) {
ESP_LOGD(TAG, "Peer certificate information:");
mbedtls_x509_crt_info((char *) info_buf, sizeof(info_buf) - 1, " ", mbedtls_ssl_get_peer_cert(&(tlsDataParams->ssl)));
ESP_LOGD(TAG, "%s", info_buf);
}
}
return (IoT_Error_t) ret;
}
IoT_Error_t iot_tls_write(Network *pNetwork, unsigned char *pMsg, size_t len, Timer *timer, size_t *written_len) {
size_t written_so_far;
bool isErrorFlag = false;
int frags, ret = 0;
TLSDataParams *tlsDataParams = &(pNetwork->tlsDataParams);
for(written_so_far = 0, frags = 0;
written_so_far < len && !has_timer_expired(timer); written_so_far += ret, frags++) {
while(!has_timer_expired(timer) &&
(ret = mbedtls_ssl_write(&(tlsDataParams->ssl), pMsg + written_so_far, len - written_so_far)) <= 0) {
if(ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
ESP_LOGE(TAG, "failed! mbedtls_ssl_write returned -0x%x", -ret);
/* All other negative return values indicate connection needs to be reset.
* Will be caught in ping request so ignored here */
isErrorFlag = true;
break;
}
}
if(isErrorFlag) {
break;
}
}
*written_len = written_so_far;
if(isErrorFlag) {
return NETWORK_SSL_WRITE_ERROR;
} else if(has_timer_expired(timer) && written_so_far != len) {
return NETWORK_SSL_WRITE_TIMEOUT_ERROR;
}
return SUCCESS;
}
IoT_Error_t iot_tls_read(Network *pNetwork, unsigned char *pMsg, size_t len, Timer *timer, size_t *read_len) {
TLSDataParams *tlsDataParams = &(pNetwork->tlsDataParams);
mbedtls_ssl_context *ssl = &(tlsDataParams->ssl);
mbedtls_ssl_config *ssl_conf = &(tlsDataParams->conf);
uint32_t read_timeout;
size_t rxLen = 0;
int ret;
read_timeout = ssl_conf->read_timeout;
while (len > 0) {
/* Make sure we never block on read for longer than timer has left,
but also that we don't block indefinitely (ie read_timeout > 0) */
mbedtls_ssl_conf_read_timeout(ssl_conf, MAX(1, MIN(read_timeout, left_ms(timer))));
ret = mbedtls_ssl_read(ssl, pMsg, len);
/* Restore the old timeout */
mbedtls_ssl_conf_read_timeout(ssl_conf, read_timeout);
if (ret > 0) {
rxLen += ret;
pMsg += ret;
len -= ret;
} else if (ret == 0 || (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret != MBEDTLS_ERR_SSL_TIMEOUT)) {
return NETWORK_SSL_READ_ERROR;
}
// Evaluate timeout after the read to make sure read is done at least once
if (has_timer_expired(timer)) {
break;
}
}
if (len == 0) {
*read_len = rxLen;
return SUCCESS;
}
if (rxLen == 0) {
return NETWORK_SSL_NOTHING_TO_READ;
} else {
return NETWORK_SSL_READ_TIMEOUT_ERROR;
}
}
IoT_Error_t iot_tls_disconnect(Network *pNetwork) {
mbedtls_ssl_context *ssl = &(pNetwork->tlsDataParams.ssl);
int ret = 0;
do {
ret = mbedtls_ssl_close_notify(ssl);
} while(ret == MBEDTLS_ERR_SSL_WANT_WRITE);
/* All other negative return values indicate connection needs to be reset.
* No further action required since this is disconnect call */
return SUCCESS;
}
IoT_Error_t iot_tls_destroy(Network *pNetwork) {
TLSDataParams *tlsDataParams = &(pNetwork->tlsDataParams);
mbedtls_net_free(&(tlsDataParams->server_fd));
mbedtls_x509_crt_free(&(tlsDataParams->clicert));
mbedtls_x509_crt_free(&(tlsDataParams->cacert));
mbedtls_pk_free(&(tlsDataParams->pkey));
mbedtls_ssl_free(&(tlsDataParams->ssl));
mbedtls_ssl_config_free(&(tlsDataParams->conf));
mbedtls_ctr_drbg_free(&(tlsDataParams->ctr_drbg));
mbedtls_entropy_free(&(tlsDataParams->entropy));
return SUCCESS;
}