tests: net: socket_tls: test different TLS configurations with sockets

This commit adds a test to showcase how to configure TLS 1.2 and 1.3
socket connections against an OpenSSL server. Only a limited number
of combinations are available for now:

- TLS 1.2
	- RSA certificate and key exchange.
	- ECDSA certificate and ECDHE key exchange.

- TLS 1.3 only supports ephemeral (ECDHE) key exchange with/without
  session tickets.

Since the goal is to test TLS connection and not low level ethernet
functionalities or similar, the only supported platform is "native_sim"
where Linux sockets are used to connect to the OpenSSL server locally.

The idea is that the Zephyr application acts a client and tries to connect
to the OpenSSL server running on the same PC. For sake of simplificity a
bash script is provided to start the OpenSSL server properly.
For completeness a bash script is also provided to re-generate
certificates and keys.

Signed-off-by: Valerio Setti <[email protected]>

tests/net/socket/tls_configurations/CMakeLists.txt

@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(tls_configurations)
+
+target_sources(app PRIVATE src/main.c)
+
+set(gen_dir ${ZEPHYR_BINARY_DIR}/include/generated/)
+
+# Helper function to convert the content of a PEM file (generated by OpenSSL)
+# to a C string that can be parsed by Mbed TLS. The format is unchanged, it's
+# still PEM, but new lines are replaced by "\n", so that both C compiler and
+# Mbed TLS parser are happy.
+function(pem_to_mbedtls target input_file)
+  file(READ credentials/${input_file} input_file_content)
+  string(REGEX REPLACE "\n" "\\\\n" input_file_content ${input_file_content})
+  set(GENERATED_FILE ${gen_dir}/${input_file}.inc)
+  file(WRITE ${GENERATED_FILE} "\"${input_file_content}\"\n")
+  generate_unique_target_name_from_filename(${input_file} generated_target_name)
+  add_custom_target(${generated_target_name} DEPENDS ${GENERATED_FILE})
+  add_dependencies(${target} ${generated_target_name})
+endfunction()
+
+pem_to_mbedtls(app ec.crt)
+pem_to_mbedtls(app rsa.crt)

tests/net/socket/tls_configurations/Kconfig

@@ -0,0 +1,8 @@
+# Copyright (c) 2024 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+config SERVER_PORT
+	int "Server port to connect to"
+	default 4242
+
+source "Kconfig.zephyr"

tests/net/socket/tls_configurations/credentials/ec-priv.key

@@ -0,0 +1,5 @@
+-----BEGIN PRIVATE KEY-----
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgwecn6Plv8ONZs2cF
+IIlr4B4xaoPYEMHm9mSG4esgQ2uhRANCAARVR4/COFJhHmmGdERod/1DhM5hBcq/
+xQHuUtxC1a977tMFCzINWTy155+/E8uj35FUhsLeFMoyGtgvKHKIBpgt
+-----END PRIVATE KEY-----

tests/net/socket/tls_configurations/credentials/ec.crt

@@ -0,0 +1,10 @@
+-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

tests/net/socket/tls_configurations/credentials/rsa-priv.key

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----

tests/net/socket/tls_configurations/credentials/rsa.crt

@@ -0,0 +1,19 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

tests/net/socket/tls_configurations/overlay-ec.conf

@@ -0,0 +1,5 @@
+CONFIG_PSA_WANT_ALG_ECDH=y
+CONFIG_PSA_WANT_ALG_ECDSA=y
+CONFIG_PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_BASIC=y
+CONFIG_PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_GENERATE=y
+CONFIG_PSA_WANT_ECC_SECP_R1_256=y

tests/net/socket/tls_configurations/overlay-rsa.conf

@@ -0,0 +1,4 @@
+CONFIG_PSA_WANT_ALG_RSA_OAEP=y
+CONFIG_PSA_WANT_ALG_RSA_PKCS1V15_CRYPT=y
+CONFIG_PSA_WANT_ALG_RSA_PKCS1V15_SIGN=y
+CONFIG_PSA_WANT_ALG_RSA_PSS=y

tests/net/socket/tls_configurations/overlay-tls12.conf

@@ -0,0 +1,8 @@
+CONFIG_MBEDTLS_TLS_VERSION_1_2=y
+CONFIG_PSA_WANT_ALG_TLS12_PRF=y
+CONFIG_PSA_WANT_KEY_TYPE_AES=y
+CONFIG_PSA_WANT_ALG_CBC_NO_PADDING=y
+CONFIG_PSA_WANT_ALG_SHA_256=y
+CONFIG_PSA_WANT_ALG_SHA_384=y
+CONFIG_PSA_WANT_KEY_TYPE_HMAC=y
+CONFIG_PSA_WANT_ALG_HMAC=y

tests/net/socket/tls_configurations/overlay-tls13.conf

@@ -0,0 +1,8 @@
+CONFIG_MBEDTLS_TLS_VERSION_1_3=y
+CONFIG_PSA_WANT_ALG_HKDF_EXTRACT=y
+CONFIG_PSA_WANT_ALG_HKDF_EXPAND=y
+
+CONFIG_PSA_WANT_ALG_GCM=y
+CONFIG_PSA_WANT_KEY_TYPE_AES=y
+CONFIG_PSA_WANT_ALG_CBC_NO_PADDING=y
+CONFIG_PSA_WANT_ALG_SHA_256=y

tests/net/socket/tls_configurations/prj.conf

@@ -0,0 +1,52 @@
+# Kernel options
+CONFIG_MAIN_STACK_SIZE=4096
+CONFIG_POSIX_API=y
+CONFIG_HEAP_MEM_POOL_SIZE=2048
+
+# Generic networking options
+CONFIG_NETWORKING=y
+
+# Socket
+CONFIG_NET_SOCKETS=y
+CONFIG_NET_SOCKETS_SOCKOPT_TLS=y
+
+# Disable native ethernet driver (using native sockets instead)
+CONFIG_ETH_NATIVE_POSIX=n
+
+# Use native sockets
+CONFIG_NET_SOCKETS=y
+CONFIG_NET_SOCKETS_OFFLOAD=y
+CONFIG_NET_DRIVERS=y
+CONFIG_NET_NATIVE_OFFLOADED_SOCKETS=y
+
+# Mbed TLS configuration
+CONFIG_MBEDTLS=y
+CONFIG_MBEDTLS_BUILTIN=y
+CONFIG_MBEDTLS_ENABLE_HEAP=y
+CONFIG_MBEDTLS_HEAP_SIZE=60000
+CONFIG_MBEDTLS_SSL_MAX_CONTENT_LEN=2048
+CONFIG_MBEDTLS_PEM_CERTIFICATE_FORMAT=y
+# Build the PSA Crypto core so that the TLS stack uses the PSA crypto API.
+CONFIG_MBEDTLS_PSA_CRYPTO_C=y
+CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG=y
+CONFIG_ENTROPY_GENERATOR=y
+
+# Disable some Kconfigs that are implied by CONFIG_NET_SOCKETS_SOCKOPT_TLS.
+# These are not wrong in general, but specific to a certain case (TLS 1.2 + RSA
+# key exchange/certificate + AES encryption). What we want here instead is to
+# have a basic configuration in this "prj.conf" file and then add algorithm
+# support in overlay files.
+CONFIG_MBEDTLS_TLS_VERSION_1_2=n
+CONFIG_MBEDTLS_KEY_EXCHANGE_RSA_ENABLED=n
+CONFIG_MBEDTLS_CIPHER_AES_ENABLED=n
+CONFIG_PSA_WANT_KEY_TYPE_AES=n
+CONFIG_PSA_WANT_ALG_CBC_NO_PADDING=n
+
+# Logging
+CONFIG_LOG=y
+CONFIG_PRINTK=y
+
+# Debug log options (optional)
+# CONFIG_NET_LOG=y
+# CONFIG_MBEDTLS_LOG_LEVEL_DBG=y
+# CONFIG_MBEDTLS_DEBUG=y

tests/net/socket/tls_configurations/pytest/conftest.py

@@ -0,0 +1,17 @@
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import pytest
+
+def pytest_addoption(parser):
+    parser.addoption('--server-type')
+    parser.addoption('--port')
+
+@pytest.fixture()
+def server_type(request):
+    return request.config.getoption('--server-type')
+
+@pytest.fixture()
+def port(request):
+    return request.config.getoption('--port')

tests/net/socket/tls_configurations/pytest/test_app_vs_openssl.py

@@ -0,0 +1,80 @@
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import logging
+import os
+import subprocess
+from twister_harness import DeviceAdapter
+
+logger = logging.getLogger(__name__)
+
+def get_arguments_from_server_type(server_type, port):
+    this_path = os.path.dirname(os.path.abspath(__file__))
+    certs_path = os.path.join(this_path, "..", "credentials")
+
+    args = ["openssl", "s_server"]
+    if server_type == "1.2-rsa":
+        args.extend(["-cert", "{}/rsa.crt".format(certs_path),
+                     "-key", "{}/rsa-priv.key".format(certs_path),
+                     "-certform", "PEM",
+                     "-tls1_2",
+                     "-cipher", "AES128-SHA256,AES256-SHA256"])
+    elif server_type == "1.2-ec":
+        args.extend(["-cert", "{}/ec.crt".format(certs_path),
+                     "-key", "{}/ec-priv.key".format(certs_path),
+                     "-certform", "PEM",
+                     "-tls1_2",
+                     "-cipher", "ECDHE-ECDSA-AES128-SHA256"])
+    elif server_type == "1.3-ephemeral":
+        args.extend(["-cert", "{}/ec.crt".format(certs_path),
+                     "-key", "{}/ec-priv.key".format(certs_path),
+                     "-certform", "PEM",
+                     "-tls1_3",
+                     "-ciphersuites", "TLS_AES_128_GCM_SHA256",
+                     "-num_tickets", "0"])
+    elif server_type == "1.3-ephemeral-tickets":
+        args.extend(["-cert", "{}/ec.crt".format(certs_path),
+                     "-key", "{}/ec-priv.key".format(certs_path),
+                     "-certform", "PEM",
+                     "-tls1_3",
+                     "-ciphersuites", "TLS_AES_128_GCM_SHA256"])
+    elif server_type == "1.3-psk-tickets":
+        args.extend(["-tls1_3",
+                     "-ciphersuites", "TLS_AES_128_GCM_SHA256",
+                     "-psk_identity", "PSK_identity", "-psk", "0102030405",
+                     "-allow_no_dhe_kex", "-nocert"])
+    else:
+        raise Exception("Wrong server type")
+
+    args.extend(["-serverpref", "-state", "-debug", "-status_verbose", "-rev",
+                 "-accept", "{}".format(port)])
+    return args
+
+def start_server(server_type, port):
+    logger.info("Server type: " + server_type)
+    args = get_arguments_from_server_type(server_type, port)
+    logger.info("Launch command:")
+    print(" ".join(args))
+    openssl = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+
+    try:
+        openssl.wait(1)
+        logger.error("Server startup failed. Here's the logs from OpenSSL:")
+        for line in openssl.stdout.readlines():
+            logger.error(line)
+        raise Exception("Server startup failed")
+    except subprocess.TimeoutExpired:
+        logger.info("Server is up")
+
+    return openssl
+
+def test_app_vs_openssl(dut: DeviceAdapter, server_type, port):
+    server = start_server(server_type, port)
+
+    logger.info("Launch Zephyr application")
+    dut.launch()
+    dut.readlines_until("Test PASSED", timeout=3.0)
+
+    logger.info("Kill server")
+    server.kill()