Add `ciphers_tls1.3` option, to allow setting TLS v1.3 ciphersuites.

Closes #1825. Thanks to Valentin Dimov.

ChangeLog.txt

@@ -86,6 +86,8 @@ Broker:
 - Fix file logging on Windows. Closes #1880.
 - Fix bridge sock not being removed from sock hash on error. Closes #1897.
 - Default for max_queued_messages has been changed to 1000.
+- Add `ciphers_tls1.3` option, to allow setting TLS v1.3 ciphersuites.
+  Closes #1825.
 
 Client library:
 - Client no longer generates random client ids for v3.1.1 clients, these are

man/mosquitto.conf.5.xml

@@ -1171,8 +1171,8 @@ log_timestamp_format %Y-%m-%dT%H:%M:%S
 							default at compile time. Certificate based TLS may be used
 							with websockets, except that only the
 							<option>cafile</option>, <option>certfile</option>,
-							<option>keyfile</option> and
-							<option>ciphers</option> options are
+							<option>keyfile</option>, <option>ciphers</option>, and
+							<option>ciphers_tls1.3</option> options are
 							supported.</para>
 						<para>Not reloaded on reload signal.</para>
 					</listitem>
@@ -1289,9 +1289,21 @@ log_timestamp_format %Y-%m-%dT%H:%M:%S
 				<varlistentry>
 					<term><option>ciphers</option> <replaceable>cipher:list</replaceable></term>
 					<listitem>
-						<para>The list of allowed ciphers, each separated with
-							a colon. Available ciphers can be obtained using
-							the "openssl ciphers" command.</para>
+                        <para>
+                            The list of allowed ciphers for this listener, for
+                            TLS v1.2 and earlier only, each separated with
+                            a colon. Available ciphers can be obtained using
+                            the "openssl ciphers" command.
+                        </para>
+					</listitem>
+				</varlistentry>
+				<varlistentry>
+					<term><option>ciphers_tls1.3</option> <replaceable>cipher:list</replaceable></term>
+					<listitem>
+                        <para>
+                            The list of allowed ciphersuites for this listener,
+                            for TLS v1.3, each separated with a colon.
+                        </para>
 					</listitem>
 				</varlistentry>
 				<varlistentry>

mosquitto.conf

@@ -257,7 +257,7 @@
 # Choose the protocol to use when listening.
 # This can be either mqtt or websockets.
 # Certificate based TLS may be used with websockets, except that only the
-# cafile, certfile, keyfile and ciphers options are supported.
+# cafile, certfile, keyfile, ciphers, and ciphers_tls13 options are supported.
 #protocol mqtt
 
 # Set use_username_as_clientid to true to replace the clientid that a client
@@ -300,9 +300,14 @@
 # If you wish to control which encryption ciphers are used, use the ciphers
 # option. The list of available ciphers can be optained using the "openssl
 # ciphers" command and should be provided in the same format as the output of
-# that command.
+# that command. This applies to TLS 1.2 and earlier versions only. Use
+# ciphers_tls1.3 for TLS v1.3.
 #ciphers
 
+# Choose which TLS v1.3 ciphersuites are used for this listener.
+# Defaults to "TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256"
+#ciphers_tls1.3
+
 # If you have require_certificate set to true, you can create a certificate
 # revocation list file to revoke access to particular client certificates. If
 # you have done this, use crlfile to point to the PEM encoded revocation file.

src/conf.c

@@ -278,6 +278,7 @@ void config__cleanup(struct mosquitto__config *config)
 			mosquitto__free(config->listeners[i].certfile);
 			mosquitto__free(config->listeners[i].keyfile);
 			mosquitto__free(config->listeners[i].ciphers);
+			mosquitto__free(config->listeners[i].ciphers_tls13);
 			mosquitto__free(config->listeners[i].psk_hint);
 			mosquitto__free(config->listeners[i].crlfile);
 			mosquitto__free(config->listeners[i].dhparamfile);
@@ -428,6 +429,7 @@ int config__parse_args(struct mosquitto__config *config, int argc, char *argv[])
 			|| config->default_listener.tls_keyform != mosq_k_pem
 			|| config->default_listener.tls_engine_kpass_sha1
 			|| config->default_listener.ciphers
+			|| config->default_listener.ciphers_tls13
 			|| config->default_listener.dhparamfile
 			|| config->default_listener.psk_hint
 			|| config->default_listener.require_certificate
@@ -492,6 +494,7 @@ int config__parse_args(struct mosquitto__config *config, int argc, char *argv[])
 		config->listeners[config->listener_count-1].certfile = config->default_listener.certfile;
 		config->listeners[config->listener_count-1].keyfile = config->default_listener.keyfile;
 		config->listeners[config->listener_count-1].ciphers = config->default_listener.ciphers;
+		config->listeners[config->listener_count-1].ciphers_tls13 = config->default_listener.ciphers_tls13;
 		config->listeners[config->listener_count-1].dhparamfile = config->default_listener.dhparamfile;
 		config->listeners[config->listener_count-1].psk_hint = config->default_listener.psk_hint;
 		config->listeners[config->listener_count-1].require_certificate = config->default_listener.require_certificate;
@@ -1173,6 +1176,13 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, struct
 					if(conf__parse_string(&token, "ciphers", &cur_listener->ciphers, saveptr)) return MOSQ_ERR_INVAL;
 #else
 					log__printf(NULL, MOSQ_LOG_WARNING, "Warning: TLS support not available.");
+#endif
+				}else if(!strcmp(token, "ciphers_tls1.3")){
+#ifdef WITH_TLS
+					if(reload) continue; /* Listeners not valid for reloading. */
+					if(conf__parse_string(&token, "ciphers_tls1.3", &cur_listener->ciphers_tls13, saveptr)) return MOSQ_ERR_INVAL;
+#else
+					log__printf(NULL, MOSQ_LOG_WARNING, "Warning: TLS support not available.");
 #endif
 				}else if(!strcmp(token, "clientid") || !strcmp(token, "remote_clientid")){
 #ifdef WITH_BRIDGE

src/mosquitto_broker_internal.h

@@ -228,6 +228,7 @@ struct mosquitto__listener {
 	char *tls_engine;
 	char *tls_engine_kpass_sha1;
 	char *ciphers;
+	char *ciphers_tls13;
 	char *psk_hint;
 	SSL_CTX *ssl_ctx;
 	char *crlfile;

src/net.c

@@ -386,6 +386,16 @@ int net__tls_server_ctx(struct mosquitto__listener *listener)
 			return MOSQ_ERR_TLS;
 		}
 	}
+#if OPENSSL_VERSION_NUMBER >= 0x10101000
+	if(listener->ciphers_tls13){
+		rc = SSL_CTX_set_ciphersuites(listener->ssl_ctx, listener->ciphers_tls13);
+		if(rc == 0){
+			log__printf(NULL, MOSQ_LOG_ERR, "Error: Unable to set TLS 1.3 ciphersuites. Check cipher_tls13 list \"%s\".", listener->ciphers_tls13);
+			return MOSQ_ERR_TLS;
+		}
+	}
+#endif
+
 	if(listener->dhparamfile){
 		dhparamfile = fopen(listener->dhparamfile, "r");
 		if(!dhparamfile){

src/websockets.c

@@ -753,6 +753,9 @@ struct libwebsocket_context *mosq_websockets_init(struct mosquitto__listener *li
 	info.ssl_cert_filepath = listener->certfile;
 	info.ssl_private_key_filepath = listener->keyfile;
 	info.ssl_cipher_list = listener->ciphers;
+#if defined(WITH_WEBSOCKETS) && LWS_LIBRARY_VERSION_NUMBER>=3001000
+	info->tls_1_3_plus_cipher_list = listener->ciphers_tls13;
+#endif
 	if(listener->require_certificate){
 		info.options |= LWS_SERVER_OPTION_REQUIRE_VALID_OPENSSL_CLIENT_CERT;
 	}