Support self signed certificates (espressif#291)

* Support self signed certificates Fix for espressif#265 mbedtls_ssl_conf_authmode was defined before mbedtls_ssl_config_defaults causing several bugs when no CA certificate is defined. * Implement Arduino's log facility Replace printf by ESP log handling * Remove \n from debug messages log_ doesn't need \n to break line.

Author: copercini

libraries/WiFiClientSecure/src/ssl_client.cpp

@@ -1,118 +1,55 @@
 /* Provide SSL/TLS functions to ESP32 with Arduino IDE
 *
-* Adapted from the ssl_client1 example in mbedtls.
+* Adapted from the ssl_client1 example of mbedtls.
 *
 * Original Copyright (C) 2006-2015, ARM Limited, All Rights Reserved, Apache 2.0 License.
 * Additions Copyright (C) 2017 Evandro Luis Copercini, Apache 2.0 License.
 */
 
 #include "Arduino.h"
+#include <esp32-hal-log.h>
 #include <lwip/sockets.h>
 #include <lwip/err.h>
 #include <lwip/sockets.h>
 #include <lwip/sys.h>
 #include <lwip/netdb.h>
-
 #include "ssl_client.h"
 
-
 const char *pers = "esp32-tls";
 
-#define DEBUG //Comment to supress debug messages
-
-#ifdef DEBUG
-#define DEBUG_PRINT(...) printf( __VA_ARGS__ )
-#else
-#define DEBUG_PRINT(x)
-#endif
-
-#ifdef CONFIG_MBEDTLS_DEBUG
-
-#define MBEDTLS_DEBUG_LEVEL 4
-
-/* mbedtls debug function that translates mbedTLS debug output
-to ESP_LOGx debug output.
-
-MBEDTLS_DEBUG_LEVEL 4 means all mbedTLS debug output gets sent here,
-and then filtered to the ESP logging mechanism.
-*/
-static void mbedtls_debug(void *ctx, int level,
- const char *file, int line,
- const char *str)
-{
- const char *MBTAG = "mbedtls";
- char *file_sep;
-
- /* 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.
- */
- file_sep = rindex(file, '/');
- if (file_sep) {
- file = file_sep + 1;
- }
-
- switch (level) {
- case 1:
- printf( "%s:%d %s \n", file, line, str);
- break;
- case 2:
- case 3:
- printf( "%s:%d %s \n", file, line, str);
- case 4:
- printf( "%s:%d %s \n", file, line, str);
- break;
- default:
- printf( "Unexpected log level %d: %s \n", level, str);
- break;
- }
-}
-
-#endif
-
-
 static int handle_error(int err)
 {
 #ifdef MBEDTLS_ERROR_C
  char error_buf[100];
-
  mbedtls_strerror(err, error_buf, 100);
- printf("\n%s\n", error_buf);
+ log_e("%s", error_buf);
 #endif
- printf("\nMbedTLS message code: %d\n", err);
+ log_e("MbedTLS message code: %d", err);
  return err;
 }
 
 
-
 void ssl_init(sslclient_context *ssl_client)
 {
- /*
- * Initialize the RNG and the session data
- */
-
  mbedtls_ssl_init(&ssl_client->ssl_ctx);
  mbedtls_ssl_config_init(&ssl_client->ssl_conf);
-
  mbedtls_ctr_drbg_init(&ssl_client->drbg_ctx);
 }
 
 
-
 int start_ssl_client(sslclient_context *ssl_client, uint32_t ipAddress, uint32_t port, const char *rootCABuff, const char *cli_cert, const char *cli_key)
 {
  char buf[512];
  int ret, flags, len, timeout;
  int enable = 1;
- DEBUG_PRINT("Free heap before TLS %u\n", xPortGetFreeHeapSize());
-
+ log_i("Free heap before TLS %u", xPortGetFreeHeapSize());
 
+ log_i("Starting socket");
  ssl_client->socket = -1;
-
+
  ssl_client->socket = lwip_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (ssl_client->socket < 0) {
- printf("\r\nERROR opening socket\r\n");
+ log_e("ERROR opening socket");
  return ssl_client->socket;
  }
 
@@ -129,69 +66,61 @@ int start_ssl_client(sslclient_context *ssl_client, uint32_t ipAddress, uint32_t
  lwip_setsockopt(ssl_client->socket, IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(enable));
  lwip_setsockopt(ssl_client->socket, SOL_SOCKET, SO_KEEPALIVE, &enable, sizeof(enable));
  } else {
- printf("\r\nConnect to Server failed!\r\n");
+ log_e("Connect to Server failed!");
  return -1;
- 
  }
 
  fcntl( ssl_client->socket, F_SETFL, fcntl( ssl_client->socket, F_GETFL, 0 ) | O_NONBLOCK );
 
-
- DEBUG_PRINT( "Seeding the random number generator\n");
+ log_i("Seeding the random number generator");
  mbedtls_entropy_init(&ssl_client->entropy_ctx);
 
  ret = mbedtls_ctr_drbg_seed(&ssl_client->drbg_ctx, mbedtls_entropy_func,
  &ssl_client->entropy_ctx, (const unsigned char *) pers, strlen(pers));
- 
- 
- 
-
  if (ret < 0) {
  return handle_error(ret);
  }
 
+ log_i("Setting up the SSL/TLS structure...");
+
+ if ((ret = mbedtls_ssl_config_defaults(&ssl_client->ssl_conf,
+ MBEDTLS_SSL_IS_CLIENT,
+ MBEDTLS_SSL_TRANSPORT_STREAM,
+ MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
+ return handle_error(ret);
+ }
 
  /* MBEDTLS_SSL_VERIFY_REQUIRED if a CA certificate is defined on Arduino IDE and
  MBEDTLS_SSL_VERIFY_NONE if not.
  */
  if (rootCABuff != NULL) {
- DEBUG_PRINT( "Loading CA cert\n");
+ log_i("Loading CA cert");
  mbedtls_x509_crt_init(&ssl_client->ca_cert);
  mbedtls_ssl_conf_authmode(&ssl_client->ssl_conf, MBEDTLS_SSL_VERIFY_REQUIRED);
  ret = mbedtls_x509_crt_parse(&ssl_client->ca_cert, (const unsigned char *)rootCABuff, strlen(rootCABuff) + 1);
  mbedtls_ssl_conf_ca_chain(&ssl_client->ssl_conf, &ssl_client->ca_cert, NULL);
  //mbedtls_ssl_conf_verify(&ssl_client->ssl_ctx, my_verify, NULL );
  if (ret < 0) {
  return handle_error(ret);
- 
- 
-
- 
  }
  } else {
- 
  mbedtls_ssl_conf_authmode(&ssl_client->ssl_conf, MBEDTLS_SSL_VERIFY_NONE);
+ log_i("WARNING: Use certificates for a more secure communication!");
  }
 
  if (cli_cert != NULL && cli_key != NULL) {
  mbedtls_x509_crt_init(&ssl_client->client_cert);
  mbedtls_pk_init(&ssl_client->client_key);
 
- DEBUG_PRINT( "Loading CRT cert\n");
+ log_i("Loading CRT cert");
 
  ret = mbedtls_x509_crt_parse(&ssl_client->client_cert, (const unsigned char *)cli_cert, strlen(cli_cert) + 1);
- 
- 
- 
-
  if (ret < 0) {
  return handle_error(ret);
  }
 
- DEBUG_PRINT( "Loading private key\n");
+ log_i("Loading private key");
  ret = mbedtls_pk_parse_key(&ssl_client->client_key, (const unsigned char *)cli_key, strlen(cli_key) + 1, NULL, 0);
- 
- 
 
  if (ret != 0) {
  return handle_error(ret);
@@ -203,89 +132,66 @@ int start_ssl_client(sslclient_context *ssl_client, uint32_t ipAddress, uint32_t
  /*
  // TODO: implement match CN verification
 
- DEBUG_PRINT( "Setting hostname for TLS session...\n");
+ log_i("Setting hostname for TLS session...");
 
  // Hostname set here should match CN in server certificate
  if((ret = mbedtls_ssl_set_hostname(&ssl_client->ssl_ctx, host)) != 0)
  {
  return handle_error(ret);
- 
- }
- */
 
- DEBUG_PRINT( "Setting up the SSL/TLS structure...\n");
-
- if ((ret = mbedtls_ssl_config_defaults(&ssl_client->ssl_conf,
- MBEDTLS_SSL_IS_CLIENT,
- MBEDTLS_SSL_TRANSPORT_STREAM,
- MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
- return handle_error(ret);
- 
- }
+ }
+ */
 
  mbedtls_ssl_conf_rng(&ssl_client->ssl_conf, mbedtls_ctr_drbg_random, &ssl_client->drbg_ctx);
-#ifdef CONFIG_MBEDTLS_DEBUG
- mbedtls_debug_set_threshold(MBEDTLS_DEBUG_LEVEL);
- mbedtls_ssl_conf_dbg(&ssl_client->ssl_conf, mbedtls_debug, NULL);
-#endif
 
  if ((ret = mbedtls_ssl_setup(&ssl_client->ssl_ctx, &ssl_client->ssl_conf)) != 0) {
  return handle_error(ret);
- 
  }
 
  mbedtls_ssl_set_bio(&ssl_client->ssl_ctx, &ssl_client->socket, mbedtls_net_send, mbedtls_net_recv, NULL );
 
- DEBUG_PRINT( "Performing the SSL/TLS handshake...\n");
+ log_i("Performing the SSL/TLS handshake...");
 
  while ((ret = mbedtls_ssl_handshake(&ssl_client->ssl_ctx)) != 0) {
- if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret != -76) {
+ if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret != -76) { //workaround for bug: https://github.com/espressif/esp-idf/issues/434
  return handle_error(ret);
- 
- 
- 
- 
  }
  delay(10);
  vPortYield();
  }
 
 
  if (cli_cert != NULL && cli_key != NULL) {
- DEBUG_PRINT("Protocol is %s \nCiphersuite is %s\n", mbedtls_ssl_get_version(&ssl_client->ssl_ctx), mbedtls_ssl_get_ciphersuite(&ssl_client->ssl_ctx));
+ log_i("Protocol is %s Ciphersuite is %s", mbedtls_ssl_get_version(&ssl_client->ssl_ctx), mbedtls_ssl_get_ciphersuite(&ssl_client->ssl_ctx));
  if ((ret = mbedtls_ssl_get_record_expansion(&ssl_client->ssl_ctx)) >= 0) {
- DEBUG_PRINT("Record expansion is %d\n", ret);
+ log_i("Record expansion is %d", ret);
  } else {
- DEBUG_PRINT("Record expansion is unknown (compression)\n");
- 
+ log_i("Record expansion is unknown (compression)");
  }
  }
 
-
- DEBUG_PRINT( "Verifying peer X.509 certificate...\n");
+ log_i("Verifying peer X.509 certificate...");
 
  if ((flags = mbedtls_ssl_get_verify_result(&ssl_client->ssl_ctx)) != 0) {
- printf( "Failed to verify peer certificate!\n");
+ log_e("Failed to verify peer certificate!");
  bzero(buf, sizeof(buf));
  mbedtls_x509_crt_verify_info(buf, sizeof(buf), " ! ", flags);
- printf( "verification info: %s\n", buf);
+ log_e("verification info: %s", buf);
  stop_ssl_socket(ssl_client, rootCABuff, cli_cert, cli_key); //It's not safe continue.
  return handle_error(ret);
  } else {
- DEBUG_PRINT( "Certificate verified.\n");
+ log_i("Certificate verified.");
  }
 
-
-
- DEBUG_PRINT("Free heap after TLS %u\n", xPortGetFreeHeapSize());
+ log_i("Free heap after TLS %u", xPortGetFreeHeapSize());
 
  return ssl_client->socket;
 }
 
 
 void stop_ssl_socket(sslclient_context *ssl_client, const char *rootCABuff, const char *cli_cert, const char *cli_key)
 {
- DEBUG_PRINT( "\nCleaning SSL connection.\n");
+ log_i("Cleaning SSL connection.");
 
  if (ssl_client->socket >= 0) {
  close(ssl_client->socket);
@@ -313,47 +219,43 @@ void stop_ssl_socket(sslclient_context *ssl_client, const char *rootCABuff, cons
 
 int data_to_read(sslclient_context *ssl_client)
 {
-
  int ret, res;
  ret = mbedtls_ssl_read(&ssl_client->ssl_ctx, NULL, 0);
- //printf("RET: %i\n",ret); //for low level debug
+ //log_e("RET: %i",ret); //for low level debug
  res = mbedtls_ssl_get_bytes_avail(&ssl_client->ssl_ctx);
- //printf("RES: %i\n",res);
- if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret < 0 && ret != -76) { //RC:76 sockets is not connected
+ //log_e("RES: %i",res);
+ if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret < 0 && ret != -76) {
  return handle_error(ret);
  }
 
  return res;
 }
 
 
-
 int send_ssl_data(sslclient_context *ssl_client, const uint8_t *data, uint16_t len)
 {
- //DEBUG_PRINT( "Writing HTTP request...\n"); //for low level debug
+ //log_i("Writing HTTP request..."); //for low level debug
  int ret = -1;
 
  while ((ret = mbedtls_ssl_write(&ssl_client->ssl_ctx, data, len)) <= 0) {
- if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret != -76) { //RC:76 sockets is not connected
+ if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret != -76) {
  return handle_error(ret);
- 
  }
  }
 
  len = ret;
- //DEBUG_PRINT( "%d bytes written\n", len); //for low level debug
+ //log_i("%d bytes written", len); //for low level debug
  return ret;
 }
 
 
-
 int get_ssl_receive(sslclient_context *ssl_client, uint8_t *data, int length)
 {
- //DEBUG_PRINT( "Reading HTTP response...\n"); //for low level debug
+ //log_i( "Reading HTTP response..."); //for low level debug
  int ret = -1;
 
  ret = mbedtls_ssl_read(&ssl_client->ssl_ctx, data, length);
 
- //DEBUG_PRINT( "%d bytes readed\n", ret); //for low level debug
+ //log_i( "%d bytes readed", ret); //for low level debug
  return ret;
 }