MQTT TLS dual mode (CA or fingeprint) in same firmware, `SetOption132 1` to force fingerprint

BUILDS.md

@@ -14,7 +14,6 @@ Note: `minimal` variant is not listed as it shouldn't be used outside of the [up
 | USE_DOMOTICZ          | - | x / x | x | x | x | - |
 | USE_HOME_ASSISTANT    | - | x / x | x | x | x | - |
 | USE_MQTT_TLS          | - | - / - | - | - | - | - |
-| USE_MQTT_TLS_CA_CERT  | - | - / - | - | - | - | - |
 | USE_MQTT_AWS_IOT      | - | - / - | - | - | - | - |
 | USE_4K_RSA            | - | - / - | - | - | - | - |
 | USE_TELEGRAM          | - | - / - | - | - | - | - |

CHANGELOG.md

@@ -11,6 +11,7 @@ All notable changes to this project will be documented in this file.
 ### Changed
 - (Internal) Range conversion edge values
 - NimBLE to v.1.3.3
+- MQTT TLS dual mode (CA or fingeprint) in same firmware, ``SetOption132 1`` to force fingerprint
 
 ### Fixed
 - Tuya dimmer range issue (#13849)

lib/lib_ssl/tls_mini/src/StackThunk_light.cpp

@@ -43,10 +43,8 @@ uint32_t stack_thunk_light_refcnt = 0;
 //#define _stackSize (5600/4)
 #if defined(USE_MQTT_AWS_IOT) || defined(USE_MQTT_AWS_IOT_LIGHT) || defined(USE_MQTT_AZURE_IOT)
   #define _stackSize (5300/4)   // using a light version of bearssl we can save 300 bytes
-#elif defined(USE_MQTT_TLS_FORCE_EC_CIPHER) || defined(USE_4K_RSA)
-  #define _stackSize (4800/4)   // no private key, we can reduce a little, max observed 4300
 #else
-  #define _stackSize (3800/4)   // using a light version of bearssl we can save 2k
+  #define _stackSize (4800/4)   // no private key, we can reduce a little, max observed 4300
 #endif
 #define _stackPaint 0xdeadbeef
 

lib/lib_ssl/tls_mini/src/WiFiClientSecureLightBearSSL.cpp

@@ -191,11 +191,7 @@ void WiFiClientSecure_light::_clear() {
   _last_error = 0;
   _recvapp_buf = nullptr;
   _recvapp_len = 0;
-#ifdef USE_MQTT_TLS_CA_CERT
+  _insecure = false;  // set to true when calling setPubKeyFingerprint()
-  _insecure = false;        // insecure (fingerprint) mode is only enabled if setPubKeyFingerprint() is called
-#else
-  _insecure = true;        // force insecure if CA validation is not enabled
-#endif
   _fingerprint_any = true; // by default accept all fingerprints
   _fingerprint1 = nullptr;
   _fingerprint2 = nullptr;
@@ -920,11 +916,7 @@ extern "C" {
   // We limit to a single cipher to reduce footprint
   // we reference it, don't put in PROGMEM
   static const uint16_t suites[] = {
-#ifdef USE_MQTT_TLS_FORCE_EC_CIPHER
     BR_TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
-#else
-    BR_TLS_RSA_WITH_AES_128_GCM_SHA256
-#endif
   };
 
   // Default initializion for our SSL clients
@@ -947,10 +939,8 @@ extern "C" {
     br_ssl_engine_set_aes_ctr(&cc->eng, &br_aes_small_ctr_vtable);
     br_ssl_engine_set_ghash(&cc->eng, &br_ghash_ctmul32);
 
-#ifdef USE_MQTT_TLS_FORCE_EC_CIPHER
     // we support only P256 EC curve for AWS IoT, no EC curve for Letsencrypt unless forced
     br_ssl_engine_set_ec(&cc->eng, &br_ec_p256_m15); // TODO
-#endif
   }
 }
 
@@ -958,9 +948,8 @@ extern "C" {
 // Returns if the SSL handshake succeeded.
 bool WiFiClientSecure_light::_connectSSL(const char* hostName) {
   // Validation context, either full CA validation or checking only fingerprints
-#ifdef USE_MQTT_TLS_CA_CERT
+
   br_x509_minimal_context *x509_minimal = nullptr;
-#endif
   br_x509_pubkeyfingerprint_context *x509_insecure = nullptr;
 
   LOG_HEAP_SIZE("_connectSSL.start");
@@ -998,7 +987,6 @@ bool WiFiClientSecure_light::_connectSSL(const char* hostName) {
     br_x509_pubkeyfingerprint_init(x509_insecure, _fingerprint1, _fingerprint2, _recv_fingerprint, _fingerprint_any);
     br_ssl_engine_set_x509(_eng, &x509_insecure->vtable);
 
-  #ifdef USE_MQTT_TLS_CA_CERT
     if (!_insecure) {
       x509_minimal = (br_x509_minimal_context*) malloc(sizeof(br_x509_minimal_context));
       if (!x509_minimal) break;
@@ -1011,7 +999,6 @@ bool WiFiClientSecure_light::_connectSSL(const char* hostName) {
       if (cfg_time > now) { now = cfg_time; }
       br_x509_minimal_set_time(x509_minimal, now / 86400 + 719528, now % 86400);
     }
-  #endif
     LOG_HEAP_SIZE("_connectSSL after DecoderContext allocation");
 
     // ============================================================
@@ -1050,9 +1037,7 @@ bool WiFiClientSecure_light::_connectSSL(const char* hostName) {
     LOG_HEAP_SIZE("_connectSSL.end, freeing StackThunk");
 #endif // ESP8266
 
-  #ifdef USE_MQTT_TLS_CA_CERT
+    free(x509_minimal);   // safe to call if nullptr
-    free(x509_minimal);
-  #endif
     free(x509_insecure);
     LOG_HEAP_SIZE("_connectSSL after release of Priv Key");
     return ret;
@@ -1065,9 +1050,7 @@ bool WiFiClientSecure_light::_connectSSL(const char* hostName) {
 #ifdef ESP8266
   stack_thunk_light_del_ref();
 #endif
-#ifdef USE_MQTT_TLS_CA_CERT
+  free(x509_minimal);   // safe to call if nullptr
-  free(x509_minimal);
-#endif
   free(x509_insecure);
   LOG_HEAP_SIZE("_connectSSL clean_on_error");
   return false;

tasmota/i18n.h

@@ -371,6 +371,7 @@
 // Commands xdrv_02_mqtt.ino
 #define D_SO_MQTTJSONONLY "MqttJSONOnly"
 #define D_SO_MQTTTLS "MqttTLS"
+#define D_SO_MQTTTLS_FINGERPRINT "MqttTLSFingerprint"
 #define D_SO_MQTTNORETAIN "MqttNoRetain"
 #define D_SO_MQTTDETACHRELAY "MqttDetachRelay"
 #define D_CMND_MQTTLOG "MqttLog"

tasmota/my_user_config.h

@@ -170,6 +170,7 @@
 #define MQTT_INDEX_SEPARATOR   false             // [SetOption64] Enable "_" instead of "-" as sensor index separator
 #define MQTT_TUYA_RECEIVED     false             // [SetOption66] Enable TuyaMcuReceived messages over Mqtt
 #define MQTT_TLS_ENABLED       false             // [SetOption103] Enable TLS mode (requires TLS version)
+#define MQTT_TLS_FINGERPRINT   false             // [SetOption132] Force TLS fingerprint validation instead of CA (requires TLS version)
 
 // -- HTTP ----------------------------------------
 #define WEB_SERVER             2                 // [WebServer] Web server (0 = Off, 1 = Start as User, 2 = Start as Admin)
@@ -430,9 +431,7 @@
 // -- MQTT - TLS - AWS IoT ------------------------
 // Using TLS starting with version v6.5.0.16 compilation will only work using Core 2.4.2 and 2.5.2. No longer supported: 2.3.0
 //#define USE_MQTT_TLS                             // Use TLS for MQTT connection (+34.5k code, +7.0k mem and +4.8k additional during connection handshake)
-//  #define USE_MQTT_TLS_CA_CERT                   // Force full CA validation instead of fingerprints, slower, but simpler to use.  (+2.2k code, +1.9k mem during connection handshake)
+//  #define USE_MQTT_TLS_CA_CERT                   // [DEPRECATED] Now TLS supports dual mode using SetOption132 - this flag is now ignored
-                                                   // This includes the LetsEncrypt CA in tasmota_ca.ino for verifying server certificates
-//  #define USE_MQTT_TLS_FORCE_EC_CIPHER           // Force Elliptic Curve cipher (higher security) required by some servers (automatically enabled with USE_MQTT_AWS_IOT) (+11.4k code, +0.4k mem)
 //  #define USE_MQTT_AWS_IOT_LIGHT                 // Enable MQTT for AWS IoT in light mode, with user/password instead of private certificate
 //  #define USE_MQTT_AWS_IOT                       // [Deprecated] Enable MQTT for AWS IoT - requires a private key (+11.9k code, +0.4k mem)
                                                  //   Note: you need to generate a private key + certificate per device and update 'tasmota/tasmota_aws_iot.cpp'
@@ -453,7 +452,6 @@
 // -- Telegram Protocol ---------------------------
 //#define USE_TELEGRAM                             // Support for Telegram protocol (+49k code, +7.0k mem and +4.8k additional during connection handshake)
   #define USE_TELEGRAM_FINGERPRINT "\xB2\x72\x47\xA6\x69\x8C\x3C\x69\xF9\x58\x6C\xF3\x60\x02\xFB\x83\xFA\x8B\x1F\x23" // Telegram api.telegram.org TLS public key fingerpring
-//  #define USE_MQTT_TLS_CA_CERT                   // Use certificate instead of fingerprint
 
 // -- KNX IP Protocol -----------------------------
 //#define USE_KNX                                  // Enable KNX IP Protocol Support (+9.4k code, +3k7 mem)
@@ -1117,10 +1115,6 @@
 
 #if defined(USE_MQTT_TLS) || defined(USE_SENDMAIL) || defined(USE_TELEGRAM) || defined(USE_WEBCLIENT_HTTPS) || defined(USE_ALEXA_AVS)
   #define USE_TLS                                  // flag indicates we need to include TLS code
-
-  #if defined(USE_MQTT_AWS_IOT) || defined(USE_TELEGRAM) || defined(USE_WEBCLIENT_HTTPS)
-    #define USE_MQTT_TLS_FORCE_EC_CIPHER           // AWS IoT and TELEGRAM require EC Cipher
-  #endif
 #endif
 
 #endif  // _MY_USER_CONFIG_H_

tasmota/settings.h

@@ -161,7 +161,7 @@ typedef union {                            // Restricted by MISRA-C Rule 18.4 bu
     uint32_t energy_phase : 1;             // bit 15 (v9.5.0.9)  - SetOption129 - (Energy) Show phase information
     uint32_t show_heap_with_timestamp : 1; // bit 16 (v9.5.0.9)  - SetOption130 - (Debug) Show heap with logging timestamp
     uint32_t tuya_allow_dimmer_0 : 1;      // bit 17 (v10.0.0.3) - SetOption131 - (Tuya) Allow save dimmer = 0 receved by MCU
-    uint32_t spare18 : 1;                  // bit 18
+    uint32_t tls_use_fingerprint : 1;      // bit 18 (v10.0.0.4) - SetOption132 - (TLS) use fingerprint validation instead of CA based
     uint32_t spare19 : 1;                  // bit 19
     uint32_t spare20 : 1;                  // bit 20
     uint32_t spare21 : 1;                  // bit 21

tasmota/settings.ino

@@ -1458,6 +1458,14 @@ void SettingsDelta(void) {
     if (Settings->version < 0x0A000003) {
       if (0 == Settings->param[P_ARP_GRATUITOUS]) {
         Settings->param[P_ARP_GRATUITOUS] = WIFI_ARP_INTERVAL;
+#ifdef USE_TLS
+        for (uint32_t i = 0; i < 20; i++) {
+          if (Settings->mqtt_fingerprint[0][i]) {
+            Settings->flag5.tls_use_fingerprint = true;   // if the fingerprint1 is non null we expect it to be actually used
+            break;
+          }
+        }
+#endif
       }
     }
 

tasmota/support_command.ino

@@ -1068,6 +1068,9 @@ void CmndSetoptionBase(bool indexed) {
                   TasmotaGlobal.restart_flag = 2;
                 }
                 break;
+              case 18:                     // SetOption132 - TLS Fingerprint
+                TasmotaGlobal.restart_flag = 2;
+                break;
             }
           }
         } else {

tasmota/tasmota_ca.ino

@@ -21,7 +21,7 @@
 // Please use fingerprint validation instead
 // However, the CA are available below for future use if it appears to be useful
 
-#if defined(USE_TLS) && defined(USE_MQTT_TLS_CA_CERT)
+#if defined(USE_TLS)
 
 /*********************************************************************************************\
  * LetsEncrypt R3 certificate, RSA 2048 bits SHA 256, valid until 20250915
@@ -232,4 +232,4 @@ const br_x509_trust_anchor GoDaddyCAG2_TA PROGMEM = {
 	}
 };
 
-#endif // defined(USE_TLS) && defined(USE_MQTT_TLS_CA_CERT)
+#endif // defined(USE_TLS)

tasmota/tasmota_configurations.h

@@ -497,9 +497,6 @@
 // -- MQTT - TLS - AWS IoT ------------------------
 #ifdef USE_ZBBRIDGE_TLS                            // Enable TLS for ZbBridge
   #define USE_MQTT_TLS                             // Use TLS for MQTT connection (+34.5k code, +7.0k mem and +4.8k additional during connection handshake)
-    #define USE_MQTT_TLS_CA_CERT                   // Force full CA validation instead of fingerprints, slower, but simpler to use.  (+2.2k code, +1.9k mem during connection handshake)
-                                                   // This includes the LetsEncrypt CA in tasmota_ca.ino for verifying server certificates
-    #define USE_MQTT_TLS_FORCE_EC_CIPHER           // Force Elliptic Curve cipher (higher security) required by some servers (automatically enabled with USE_MQTT_AWS_IOT) (+11.4k code, +0.4k mem)
     #define USE_MQTT_AWS_IOT_LIGHT                 // Enable MQTT for AWS IoT in light mode, with user/password instead of private certificate
   #define USE_TLS                                  // flag indicates we need to include TLS code
 #endif                                             // USE_ZBBRIDGE_TLS

tasmota/xdrv_02_9_mqtt.ino

@@ -48,11 +48,11 @@ const char kMqttCommands[] PROGMEM = "|"  // No prefix
   // SetOption synonyms
   D_SO_MQTTJSONONLY "|"
 #ifdef USE_MQTT_TLS
-  D_SO_MQTTTLS "|"
+  D_SO_MQTTTLS "|" D_SO_MQTTTLS_FINGERPRINT "|"
 #endif
   D_SO_MQTTNORETAIN "|" D_SO_MQTTDETACHRELAY "|"
   // regular commands
-#if defined(USE_MQTT_TLS) && !defined(USE_MQTT_TLS_CA_CERT)
+#if defined(USE_MQTT_TLS)
   D_CMND_MQTTFINGERPRINT "|"
 #endif
   D_CMND_MQTTUSER "|" D_CMND_MQTTPASSWORD "|" D_CMND_MQTTKEEPALIVE "|" D_CMND_MQTTTIMEOUT "|" D_CMND_MQTTWIFITIMEOUT "|"
@@ -70,18 +70,13 @@ const char kMqttCommands[] PROGMEM = "|"  // No prefix
 SO_SYNONYMS(kMqttSynonyms,
   90,
 #ifdef USE_MQTT_TLS
-  103,
+  103, 132,
 #endif
   104, 114
 );
 
-// const uint8_t kMqttSynonyms[] PROGMEM = {
-//   4,  // number of synonyms
-//   90, 103, 104, 114,
-// };
-
 void (* const MqttCommand[])(void) PROGMEM = {
-#if defined(USE_MQTT_TLS) && !defined(USE_MQTT_TLS_CA_CERT)
+#if defined(USE_MQTT_TLS)
   &CmndMqttFingerprint,
 #endif
   &CmndMqttUser, &CmndMqttPassword, &CmndMqttKeepAlive, &CmndMqttTimeout, &CmndMqttWifiTimeout,
@@ -231,9 +226,9 @@ void MqttInit(void) {
     }
 #endif
 
-#ifdef USE_MQTT_TLS_CA_CERT
+    if (!Settings->flag5.tls_use_fingerprint) {
       tlsClient->setTrustAnchor(Tasmota_TA, nitems(Tasmota_TA));
-#endif // USE_MQTT_TLS_CA_CERT
+    }
 
     MqttClient.setClient(*tlsClient);
   } else {
@@ -953,7 +948,7 @@ void MqttConnected(void) {
 void MqttReconnect(void) {
   char stopic[TOPSZ];
 
-  Mqtt.allowed = Settings->flag.mqtt_enabled;  // SetOption3 - Enable MQTT
+  Mqtt.allowed = Settings->flag.mqtt_enabled && (TasmotaGlobal.restart_flag == 0);  // SetOption3 - Enable MQTT, and don't connect if restart in process
   if (Mqtt.allowed) {
 #if defined(USE_MQTT_AZURE_DPS_SCOPEID) && defined(USE_MQTT_AZURE_DPS_PRESHAREDKEY)
   ProvisionAzureDPS();
@@ -1043,11 +1038,11 @@ void MqttReconnect(void) {
   MqttClient.setServer(SettingsText(SET_MQTT_HOST), Settings->mqtt_port);
 
   uint32_t mqtt_connect_time = millis();
-#if defined(USE_MQTT_TLS) && !defined(USE_MQTT_TLS_CA_CERT)
+#if defined(USE_MQTT_TLS)
-  bool allow_all_fingerprints;
+  bool allow_all_fingerprints = false;
-  bool learn_fingerprint1;
+  bool learn_fingerprint1 = false;
-  bool learn_fingerprint2;
+  bool learn_fingerprint2 = false;
-  if (Mqtt.mqtt_tls) {
+  if (Mqtt.mqtt_tls && Settings->flag5.tls_use_fingerprint) {
     allow_all_fingerprints = false;
     learn_fingerprint1 = is_fingerprint_mono_value(Settings->mqtt_fingerprint[0], 0x00);
     learn_fingerprint2 = is_fingerprint_mono_value(Settings->mqtt_fingerprint[1], 0x00);
@@ -1094,7 +1089,8 @@ void MqttReconnect(void) {
       if (!tlsClient->getMFLNStatus()) {
         AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_MQTT "MFLN not supported by TLS server"));
       }
-#ifndef USE_MQTT_TLS_CA_CERT  // don't bother with fingerprints if using CA validation
+
+      if (Settings->flag5.tls_use_fingerprint) {    // CA validation
         const uint8_t *recv_fingerprint = tlsClient->getRecvPubKeyFingerprint();
         // create a printable version of the fingerprint received
         char buf_fingerprint[64];
@@ -1122,7 +1118,8 @@ void MqttReconnect(void) {
 
           SettingsSaveAll();  // save settings
         }
-#endif // !USE_MQTT_TLS_CA_CERT
+      }
+
     }
 #endif // USE_MQTT_TLS
     MqttConnected();
@@ -1275,7 +1272,7 @@ bool KeyTopicActive(uint32_t key) {
  * Commands
 \*********************************************************************************************/
 
-#if defined(USE_MQTT_TLS) && !defined(USE_MQTT_TLS_CA_CERT)
+#if defined(USE_MQTT_TLS)
 void CmndMqttFingerprint(void) {
   if ((XdrvMailbox.index > 0) && (XdrvMailbox.index <= 2)) {
     char fingerprint[60];

tasmota/xdrv_40_telegram.ino

@@ -47,13 +47,8 @@
 #define TELEGRAM_SEND_RETRY        4    // Retries
 #define TELEGRAM_MAX_MESSAGES      2
 
-#ifdef USE_MQTT_TLS_CA_CERT
 static const uint32_t tls_rx_size = 2048;   // since Telegram CA is bigger than 1024 bytes, we need to increase rx buffer
 static const uint32_t tls_tx_size = 1024;
-#else
-  static const uint32_t tls_rx_size = 1024;
-  static const uint32_t tls_tx_size = 1024;
-#endif
 
 #include "WiFiClientSecureLightBearSSL.h"
 BearSSL::WiFiClientSecure_light *telegramClient = nullptr;
@@ -87,11 +82,13 @@ bool TelegramInit(void) {
   if (strlen(SettingsText(SET_TELEGRAM_TOKEN))) {
     if (!telegramClient) {
       telegramClient = new BearSSL::WiFiClientSecure_light(tls_rx_size, tls_tx_size);
-#ifdef USE_MQTT_TLS_CA_CERT
+
-      telegramClient->setTrustAnchor(&GoDaddyCAG2_TA, 1);
+      if (Settings.flag5.tls_use_fingerprint) {
-#else
         telegramClient->setPubKeyFingerprint(Telegram_Fingerprint, Telegram_Fingerprint, false); // check server fingerprint
-#endif
+      } else {
+        telegramClient->setTrustAnchor(&GoDaddyCAG2_TA, 1);
+      }
+
       Telegram.message_count = 0;     // Number of received messages
       Telegram.next_update_id = 0;    // Code of last read Message
       Telegram.message[0].text = "";