WIP: tests: add protocol-mark-allowlisting

Signed-off-by: Alexander Sosedkin <asosedkin@redhat.com>

tests/Makefile.am

@@ -112,7 +112,7 @@ noinst_LTLIBRARIES = libutils.la
 libutils_la_SOURCES = utils.h utils.c seccomp.c utils-adv.c
 libutils_la_LIBADD = ../lib/libgnutls.la
 
-indirect_tests = system-override-hash system-override-sig system-override-sig-tls
+indirect_tests = system-override-hash system-override-sig system-override-sig-tls protocol-mark-allowlisting
 
 ctests = tls13/supported_versions tls13/tls12-no-tls13-exts \
 	tls13/post-handshake-with-cert tls13/post-handshake-without-cert \
@@ -524,7 +524,8 @@ dist_check_SCRIPTS += system-override-sig-allowlist.sh \
 	system-override-hash-allowlist.sh \
 	system-override-versions-allowlist.sh \
 	system-override-curves-allowlist.sh \
-	system-override-special-allowlist.sh
+	system-override-special-allowlist.sh \
+	protocol-mark-allowlisting.sh
 endif
 
 dist_check_SCRIPTS += gnutls-cli-self-signed.sh gnutls-cli-invalid-crl.sh gnutls-cli-rawpk.sh

tests/protocol-mark-allowlisting.c

+/*
+ * Copyright (C) 2021 Red Hat, Inc.
+ *
+ * Author: Alexander Sosedkin
+ *
+ * This file is part of GnuTLS.
+ *
+ * GnuTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GnuTLS; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <errno.h>
+#include <netinet/tcp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+
+#include "utils.h"
+
+/*
+ * This is not a test!
+ * This is a helper for the real test in protocol-mark-allowlisting.sh.
+ * It executes sequences of commands like:
+ *     > connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+ *     > protocol_mark_disabled TLS1.2 -> OK
+ *     > connect -> bad priority: (actually, any arrow-less text can go here)
+ * where `connect` connects to $TEST_SERVER_PORT using $TEST_SERVER_CA,
+ * and protocol_mark_{disabled,enabled} simply call the underlying API.
+ * leaving the outer test to check return code and output:
+ *     connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+ *     protocol_mark_disabled TLS1.2 -> OK
+ *     connect -> bad priority: No or insufficient priorities were set.
+ */
+
+#define _assert(cond, format, ...) if (!(cond)) \
+	_fail("Assertion `" #cond "` failed: " format "\n", ##__VA_ARGS__)
+#define _check(cond) if (!(cond)) _fail("Assertion `" #cond "` failed.")
+
+unsigned parse_port(const char* port_str);
+gnutls_protocol_t parse_protocol(const char* name);
+void test_echo_server(gnutls_session_t session);
+void cmd_connect(const char* ca_file, unsigned port);
+void cmd_protocol_mark_disabled(const char* name);
+void cmd_protocol_mark_enabled(const char* name);
+const char* unprefix(const char* s, const char* prefix);
+
+
+unsigned parse_port(const char* port_str)
+{
+	unsigned port;
+	errno = 0;
+	port = strtoul(port_str, NULL, 10);
+	_assert(!errno, "Could not parse port value '%s'\n", port_str);
+	_assert(0 < port && port < (1UL << 16), "Invalid port %u\n", port);
+	return port;
+}
+
+
+gnutls_protocol_t parse_protocol(const char* name)
+{
+	gnutls_protocol_t p;
+	p = gnutls_protocol_get_id(name);
+	_assert(p != GNUTLS_VERSION_UNKNOWN, "Unknown protocol `%s`", name);
+	return p;
+}
+
+
+void test_echo_server(gnutls_session_t session)
+{
+	const char buf_out[] = "1234567\n";
+	char buf_in[sizeof(buf_out) - 1];
+	unsigned rd = 0, wr = 0;
+	unsigned LEN = sizeof(buf_out) - 1;
+	int r;
+
+	do {
+                r = gnutls_record_send(session, buf_out + wr, LEN - wr);
+		if (r == GNUTLS_E_AGAIN || r == GNUTLS_E_INTERRUPTED)
+			continue;
+		_assert(r > 0, "error in send: %s\n", gnutls_strerror(r));
+		wr += r;
+        } while(r > 0 && wr < LEN);
+	_assert(wr == LEN, "error sending all data (%u/%u)\n", wr, LEN);
+
+	do {
+                r = gnutls_record_recv(session, buf_in + rd, LEN - rd);
+		if (r == GNUTLS_E_AGAIN || r == GNUTLS_E_INTERRUPTED)
+			continue;
+		_assert(r > 0, "error in recv: %s\n", gnutls_strerror(r));
+		rd += r;
+        } while(r > 0 && rd < LEN);
+	_assert(rd == LEN, "error receiving all data (%u/%u)\n", rd, LEN);
+	_assert(!gnutls_record_check_pending(session), "data left unreceived");
+
+	_assert(!memcmp(buf_in, buf_out, LEN), "send/recv data mismatch\n");
+}
+
+void cmd_connect(const char* ca_file, unsigned port)
+{
+	char* desc;
+	int sock, r;
+	gnutls_session_t session;
+	gnutls_certificate_credentials_t cred;
+	int sock_flags = 1;
+
+	_check(gnutls_init(&session, GNUTLS_CLIENT) >= 0);
+	r = gnutls_set_default_priority(session);
+	if (r < 0) {
+		printf("connect -> bad priority: %s\n", gnutls_strerror(r));
+		gnutls_deinit(session);
+		return;
+	}
+
+	_check(gnutls_server_name_set(session, GNUTLS_NAME_DNS,
+				"example.com", strlen("example.com")) >= 0);
+	gnutls_session_set_verify_cert(session, "example.com", 0);
+
+	_check(gnutls_certificate_allocate_credentials(&cred) >= 0);
+	_check(gnutls_certificate_set_x509_trust_file(cred,
+			ca_file, GNUTLS_X509_FMT_PEM) == 1);
+	_check(gnutls_credentials_set(session,
+			GNUTLS_CRD_CERTIFICATE, cred) >= 0);
+
+	sock = tcp_connect("127.0.0.1", port);
+	_assert(sock != -1, "Connection to 127.0.0.1:%u has failed!", port);
+	_assert(setsockopt(sock, SOL_TCP, TCP_NODELAY,
+			&sock_flags, sizeof(int)) == 0, "setsockopt failed");
+
+	gnutls_transport_set_int(session, sock);
+	gnutls_handshake_set_timeout(session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
+	do {
+		r = gnutls_handshake(session);
+	} while (r < 0 && !gnutls_error_is_fatal(r));
+
+	if (r >= 0) {
+		desc = gnutls_session_get_desc(session);
+		_check(desc);
+		printf("connect -> connection established: %s\n", desc);
+		gnutls_free(desc);
+	} else {
+		printf("connect -> handshake failed: %s\n", gnutls_strerror(r));
+	}
+
+	gnutls_bye(session, GNUTLS_SHUT_RDWR);
+	shutdown(sock, SHUT_RDWR);
+	close(sock);
+	gnutls_certificate_free_credentials(cred);
+	gnutls_deinit(session);
+}
+
+
+void cmd_protocol_mark_disabled(const char* name)
+{
+	_check(gnutls_protocol_mark_disabled(parse_protocol(name)) >= 0);
+	printf("protocol_mark_disabled %s -> OK\n", name);
+}
+
+
+void cmd_protocol_mark_enabled(const char* name)
+{
+	_check(gnutls_protocol_mark_enabled(parse_protocol(name)) >= 0);
+	printf("protocol_mark_enabled %s -> OK\n", name);
+}
+
+
+// Returns 0 if `s` doesn't start with `prefix`, pointer past prefix otherwise.
+const char* unprefix(const char* s, const char* prefix)
+{
+	while (*s && *prefix && *s == *prefix)
+		s++, prefix++;
+	return *prefix ? NULL : s;
+}
+
+
+#define MAX_CMD_LEN 127
+void doit(void)
+{
+	unsigned port;
+	const char* port_str;
+	const char* ca_file;
+	const char* p;
+	char cmd_buf[MAX_CMD_LEN + 1];
+	char* e;
+
+	ca_file = getenv("TEST_SERVER_CA");
+	_assert(ca_file, "TEST_SERVER_CA is not set");
+	port_str = getenv("TEST_SERVER_PORT");
+	_assert(port_str, "TEST_SERVER_PORT is not set");
+	port = parse_port(port_str);
+
+	_check(gnutls_global_init() >= 0);
+
+	while (!feof(stdin)) {
+		memset(cmd_buf, '\0', MAX_CMD_LEN + 1);
+		fgets(cmd_buf, MAX_CMD_LEN, stdin);
+		e = strchr(cmd_buf, '\n');
+		if (e)
+			*e = '\0';
+		if (!*cmd_buf)
+			continue;
+		else if (!strcmp(cmd_buf, "> connect"))
+			cmd_connect(ca_file, port);
+		else if ((p = unprefix(cmd_buf, "> protocol_mark_disabled ")))
+			cmd_protocol_mark_disabled(p);
+		else if ((p = unprefix(cmd_buf, "> protocol_mark_enabled ")))
+			cmd_protocol_mark_enabled(p);
+		else if (unprefix(cmd_buf, "> "))
+			_fail("Unknown command `%s`\n", p);
+		else
+			_fail("Invalid line `%s`, does not start with `> `\n",
+					cmd_buf);
+	}
+
+	gnutls_global_deinit();
+	exit(0);
+}

tests/protocol-mark-allowlisting.sh

+#!/bin/sh
+
+# Copyright (C) 2021 Red Hat, Inc.
+#
+# Author: Alexander Sosedkin
+#
+# This file is part of GnuTLS.
+#
+# GnuTLS is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at
+# your option) any later version.
+#
+# GnuTLS is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GnuTLS; if not, write to the Free Software Foundation,
+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+# The test verifies that gnutls_protocol_mark_{disabled,enabled}
+# behave sensibly. The test requires allowlisting and is to be executed
+# from within the shell wrapper protocol-mark-allowlisting.sh
+# The shell part of it feeds commands into a C helper
+# and compares its output to the reference output.
+
+: ${srcdir=.}
+: ${builddir=.}
+: ${CERTTOOL=../src/certtool${EXEEXT}}
+: ${SERV=../src/gnutls-serv${EXEEXT}}
+: ${CLI=../src/gnutls-cli${EXEEXT}}
+: ${GREP=grep}
+: ${DIFF=diff}
+: ${SED=sed}
+: ${CAT=cat}
+. "${srcdir}/scripts/common.sh"
+
+for tool in "${CERTTOOL}" "${SERV}" "${CLI}"; do
+	if ! test -x "$tool"; then
+		exit 77
+	fi
+done
+
+if ! test -z "${VALGRIND}"; then
+	VALGRIND="${LIBTOOL:-libtool} --mode=execute ${VALGRIND} --error-exitcode=15"
+fi
+
+TMPFILE_TEMPLATE=template.$$.tmpl.tmp
+TMPFILE_CERT=cert.$$.pem.tmp
+TMPFILE_KEY=key.$$.pem.tmp
+TMPFILE_CONFIG=cfg.$$.tmp
+TMPFILE_LIST=lst.$$.tmp
+TMPFILE_INPUT_SCRIPT=input.$$.script.tmp
+TMPFILE_OBSERVED_LOG=observed.$$.log.tmp
+TMPFILE_EXPECTED_LOG=expected.$$.log.tmp
+
+# Set up cleanup
+
+SERVER_PID=""
+cleanup() {
+	test -z "${SERVER_PID}" || kill "${SERVER_PID}"
+	rm -f "${TMPFILE_CERT}" "${TMPFILE_KEY}"
+	rm -f "${TMPFILE_CONFIG}" "${TMPFILE_LIST}"
+	rm -f "${TMPFILE_INPUT_SCRIPT}"
+	rm -f "${TMPFILE_OBSERVED_LOG}" "${TMPFILE_EXPECTED_LOG}"
+}
+trap cleanup 1 15 2 EXIT
+
+# Generate server keys
+
+${CAT} > "$TMPFILE_TEMPLATE" << EOF
+organization = test
+cn = example.com
+ca
+tls_www_server
+dns_name = example.com
+EOF
+"${CERTTOOL}" --generate-privkey --key-type=rsa --hash sha256 \
+	--outfile "${TMPFILE_KEY}"
+"${CERTTOOL}" --generate-self-signed --load-privkey "${TMPFILE_KEY}" \
+	--template "${TMPFILE_TEMPLATE}" --outfile "${TMPFILE_CERT}"
+
+# Set up a configuration file using allowlisting allowing for TLS 1.2 only,
+# but also allowing to enable 1.1 and 1.3.
+
+${CAT} <<_EOF_ > "${TMPFILE_CONFIG}"
+# this following is listed to allow
+# 1.3's TLS_AES_128_GCM_SHA256, but not allowlist 1.3 itself
+# 1.2's TLS_RSA_AES_128_GCM_SHA256
+# 1.1's TLS_RSA_AES_128_CBC_SHA1, but not allowlist 1.1 itself
+
+[global]
+override-mode = allowlist
+
+[overrides]
+secure-hash = SHA256
+tls-enabled-mac = AEAD  # for 1.2, 1.3
+tls-enabled-mac = SHA1  # for 1.1
+tls-enabled-group = GROUP-FFDHE3072
+secure-sig = RSA-PSS-RSAE-SHA256  # for 1.3
+secure-sig = RSA-SHA256           # for 1.2, 1.1
+tls-enabled-cipher = AES-128-GCM  # for 1.2, 1.3
+tls-enabled-cipher = AES-128-CBC  # for 1.1
+tls-enabled-kx = RSA
+# enabled-version = TLS1.3  # intentional, to be tested for reenablement
+enabled-version = TLS1.2    # to be tested for disabling later
+# enabled-version = TLS1.1  # intentional, to be tested for reenablement
+_EOF_
+with_config_file() {
+	GNUTLS_SYSTEM_PRIORITY_FILE="${TMPFILE_CONFIG}" \
+	GNUTLS_SYSTEM_PRIORITY_FAIL_ON_INVALID=1 \
+	"$@"  # preserve $?, callers rely on it
+}
+
+# Smoke --list, @SYSTEM
+
+with_config_file "${CLI}" --list -d 4 --priority @SYSTEM &>"${TMPFILE_LIST}"
+if test $? != 0; then
+	${CAT} "${TMPFILE_LIST}"
+	echo 'fails with just @SYSTEM'
+	exit 1
+fi
+if ! ${GREP} -Fqx 'Protocols: VERS-TLS1.2' "${TMPFILE_LIST}"; then
+	${CAT} "${TMPFILE_LIST}"
+	echo 'unexpected protocol list with @SYSTEM, must be just VERS-TLS1.2'
+	exit 1
+fi
+
+# Smoke-test that TLS 1.3 is enableable with these algorithms
+
+with_config_file \
+	"${CLI}" --list -d 4 --priority @SYSTEM:+VERS-TLS1.3 &>"${TMPFILE_LIST}"
+if test $? != 0; then
+	${CAT} "${TMPFILE_LIST}"
+	echo 'listing algorithms fails with @SYSTEM:+VERS-TLS1.3'
+	exit 1
+fi
+if ! ${GREP} -Fqx 'Protocols: VERS-TLS1.2, VERS-TLS1.3' "${TMPFILE_LIST}"; then
+	${CAT} "${TMPFILE_LIST}"
+	echo 'could not enable TLS 1.3 with a @SYSTEM:+VERS-TLS1.3'
+	exit 1
+fi
+
+# Smoke-test that TLS 1.1 is enableable with these algorithms
+
+with_config_file \
+	"${CLI}" --list -d 4 --priority @SYSTEM:+VERS-TLS1.1 &>"${TMPFILE_LIST}"
+if test $? != 0; then
+	${CAT} "${TMPFILE_LIST}"
+	echo 'listing algorithms fails with @SYSTEM:+VERS-TLS1.1'
+	exit 1
+fi
+if ! ${GREP} -Fqx 'Protocols: VERS-TLS1.2, VERS-TLS1.1' "${TMPFILE_LIST}"; then
+	${CAT} "${TMPFILE_LIST}"
+	echo 'could not enable TLS 1.1 with a @SYSTEM:+VERS-TLS1.1'
+	exit 1
+fi
+
+### Harness for the actual tests
+
+test_with_helper() {
+	${CAT} > "$TMPFILE_EXPECTED_LOG"
+	${SED} 's/\(.*\) -> .*/> \1/' "${TMPFILE_EXPECTED_LOG}" \
+		> "${TMPFILE_INPUT_SCRIPT}"
+	with_config_file env \
+		TEST_SERVER_PORT=$PORT \
+		TEST_SERVER_CA="$TMPFILE_CERT" \
+		GNUTLS_DEBUG_LEVEL=9 \
+		"${builddir}/protocol-mark-allowlisting" \
+			< "${TMPFILE_INPUT_SCRIPT}" > "${TMPFILE_OBSERVED_LOG}"
+	RETCODE=$?
+	${DIFF} -u "${TMPFILE_EXPECTED_LOG}" "${TMPFILE_OBSERVED_LOG}"
+	DIFF_RETCODE=$?
+	if [ $DIFF_RETCODE != 0 ]; then
+		echo
+		echo 'protocol-mark-allowlisting(.c) output is unexpected'
+		echo '--- expected ---'
+		${CAT} "${TMPFILE_EXPECTED_LOG}"
+		echo '--- observed ---'
+		${CAT} "${TMPFILE_OBSERVED_LOG}"
+		exit 1
+	fi
+	if [ $RETCODE != 0 ]; then
+		echo "protocol-mark-allowlisting(.c) failed with $RETCODE"
+		exit 1
+	fi
+}
+
+### Tests against a TLS 1.2 -only server
+
+eval "${GETPORT}"
+# server is launched without allowlisting config file in effect
+launch_server --echo --priority "NORMAL:-VERS-TLS-ALL:+VERS-TLS1.2" \
+	--x509keyfile "${TMPFILE_KEY}" --x509certfile "${TMPFILE_CERT}"
+SERVER_PID=$!
+wait_server ${SERVER_PID}
+
+# ["gnutls_protocol_mark_disabled disables, TLS"]
+# With a configuration file allowlisting a specific TLS protocol version (1.2),
+# gnutls_protocol_mark_disabled with that version.
+test_with_helper <<EOF
+connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+protocol_mark_disabled TLS1.2 -> OK
+connect -> bad priority: No or insufficient priorities were set.
+EOF
+
+# ["gnutls_protocol_mark_disabled disables revertibly, TLS"]
+# consecutive gnutls_protocol_mark_enabled makes connection possible
+# (with a different session handle).
+test_with_helper <<EOF
+connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+protocol_mark_disabled TLS1.2 -> OK
+connect -> bad priority: No or insufficient priorities were set.
+protocol_mark_enabled TLS1.2 -> OK
+connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+EOF
+
+# Just a random long-ish scenario
+test_with_helper <<EOF
+connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+protocol_mark_disabled TLS1.2 -> OK
+connect -> bad priority: No or insufficient priorities were set.
+protocol_mark_enabled TLS1.3 -> OK
+connect -> bad priority: No or insufficient priorities were set.
+protocol_mark_disabled TLS1.3 -> OK
+protocol_mark_enabled TLS1.2 -> OK
+connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+EOF
+
+# !!! CURRENTLY NOT WORKING AS EXPECTED !!!
+# Insufficient priority vs handshake failed
+#test_with_helper <<EOF
+#protocol_mark_disabled TLS1.2 -> OK
+#connect -> bad priority: No or insufficient priorities were set.
+#protocol_mark_enabled TLS1.3 -> OK
+#connect -> handshake failed: A packet with illegal or unsupported version was received.
+#EOF
+
+terminate_proc ${SERVER_PID}
+
+### Tests against a NORMAL server (all three TLS versions enabled)
+
+eval "${GETPORT}"
+# server is launched without allowlisting config file in effect
+launch_server -d9 --echo --priority NORMAL \
+	--x509keyfile "${TMPFILE_KEY}" --x509certfile "${TMPFILE_CERT}"
+SERVER_PID=$!
+wait_server ${SERVER_PID}
+
+# !!! CURRENTLY NOT WORKING AS EXPECTED !!!
+# smoke-test protocol_mark_enabled
+#test_with_helper <<EOF
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#protocol_mark_enabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.3)-(DHE-FFDHE3072)-(RSA-PSS-RSAE-SHA256)-(AES-128-GCM)
+#EOF
+
+# !!! CURRENTLY NOT WORKING AS EXPECTED !!!
+# ["gnutls_protocol_mark_enabled enables, TLS"]
+# with a configuration file not allowlisting a specific TLS protocol version,
+# gnutls_protocol_mark_enabled with that version allows
+# connecting to a server accepting this TLS protocol version alone,
+#test_with_helper <<EOF
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#protocol_mark_enabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.3)-(DHE-FFDHE3072)-(RSA-PSS-RSAE-SHA256)-(AES-128-GCM)
+#EOF
+
+# !!! CURRENTLY NOT WORKING AS EXPECTED !!!
+# ["gnutls_protocol_mark_enabled enables revertibly, TLS"]
+# consecutive gnutls_protocol_mark_disabled
+# prevents the client from connecting (with a different session handle)
+#test_with_helper <<EOF
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#protocol_mark_enabled TLS1.1 -> OK
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#protocol_mark_disabled TLS1.2 -> OK
+#connect -> connection established: (TLS1.1)-(RSA)-(AES-128-CBC)-(SHA1)
+#protocol_mark_disabled TLS1.1 -> OK
+#connect -> bad priority: No or insufficient priorities were set.
+#EOF
+# Alternative one
+#test_with_helper <<EOF
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#protocol_mark_enabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.3)-(DHE-FFDHE3072)-(RSA-PSS-RSAE-SHA256)-(AES-128-GCM)
+#protocol_mark_disabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#EOF
+
+# !!! CURRENTLY NOT WORKING AS EXPECTED !!!
+# ["gnutls_protocol_mark_disabled disables selectively, TLS"]
+# gnutls_protocol_mark_disabled with a specific version
+# doesn't disable other previously enabled version.
+# ["gnutls_protocol_mark_enabled enables selectively, TLS"]
+# gnutls_protocol_mark_enabled with a specific version
+# doesn't enable other previously disabled version.
+#test_with_helper <<EOF
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#protocol_mark_enabled TLS1.3 -> OK
+#protocol_mark_enabled TLS1.2 -> OK
+#protocol_mark_enabled TLS1.1 -> OK
+#connect -> connection established: (TLS1.3)-(DHE-FFDHE3072)-(RSA-PSS-RSAE-SHA256)-(AES-128-GCM)
+#protocol_mark_disabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.2)-(RSA)-(AES-128-GCM)
+#protocol_mark_disabled TLS1.2 -> OK
+#connect -> connection established: (TLS1.1)-(RSA)-(AES-128-CBC)-(SHA1)
+#protocol_mark_disabled TLS1.1 -> OK
+#connect -> bad priority: No or insufficient priorities were set.
+#protocol_mark_enabled TLS1.1 -> OK
+#connect -> connection established: (TLS1.1)-(RSA)-(AES-128-CBC)-(SHA1)
+#protocol_mark_enabled TLS1.2 -> OK
+#connect -> connection established: (TLS1.1)-(RSA)-(AES-128-CBC)-(SHA1)
+#protocol_mark_enabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.3)-(DHE-FFDHE3072)-(RSA-PSS-RSAE-SHA256)-(AES-128-GCM)
+#EOF
+
+terminate_proc ${SERVER_PID}
+
+### Tests against a TLS 1.1 & 1.3 server (1.2 disabled)
+
+eval "${GETPORT}"
+# server is launched without allowlisting config file in effect
+launch_server -d9 --echo \
+	--priority "NORMAL:-VERS-TLS-ALL:+VERS-TLS1.1:+VERS-TLS1.3" \
+	--x509keyfile "${TMPFILE_KEY}" --x509certfile "${TMPFILE_CERT}"
+SERVER_PID=$!
+wait_server ${SERVER_PID}
+
+# !!! CURRENTLY NOT WORKING AS EXPECTED !!!
+#test_with_helper <<EOF
+#connect -> handshake failed: A packet with illegal or unsupported version was received.
+#protocol_mark_enabled TLS1.1 -> OK
+#connect -> connection established: (TLS1.1)-(RSA)-(AES-128-CBC)-(SHA1)
+#protocol_mark_enabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.3)-(DHE-FFDHE3072)-(RSA-PSS-RSAE-SHA256)-(AES-128-GCM)
+#protocol_mark_disabled TLS1.3 -> OK
+#connect -> connection established: (TLS1.1)-(RSA)-(AES-128-CBC)-(SHA1)
+#protocol_mark_disabled TLS1.1 -> OK
+#connect -> handshake failed: A packet with illegal or unsupported version was received.
+#protocol_mark_disabled TLS1.2 -> OK
+#connect -> bad priority: No or insufficient priorities were set.
+#EOF
+
+terminate_proc ${SERVER_PID}
+
+exit 0