How to test TLS 1.3 in zephyr?

[SanjayyyV]

Hi all, I am running into an issue while trying to use the tests/net/socket/tls_configurations/ to test the working of TLS v1.3.

Though, I've explicitly disabled the CONFIG_MBEDTLS_TLS_VERSION_1_2 and I've created the socket using TLS 1.3, I've still only been able to view the TLS 1.2 Client hello messages on wireshark. Is there any MbedTLS configuration that I am missing or some other configuration that defaults to TLS 1.2 by default?

Here's the diff:
`diff --git a/tests/net/socket/tls_configurations/overlay-tls13.conf b/tests/net/socket/tls_configurations/overlay-tls13.conf
index 5c311f3027c..6464f49b7af 100644
--- a/tests/net/socket/tls_configurations/overlay-tls13.conf
+++ b/tests/net/socket/tls_configurations/overlay-tls13.conf
@@ -1,3 +1,4 @@
+CONFIG_MBEDTLS_TLS_VERSION_1_2=n
CONFIG_MBEDTLS_TLS_VERSION_1_3=y
CONFIG_PSA_WANT_ALG_HKDF_EXTRACT=y
CONFIG_PSA_WANT_ALG_HKDF_EXPAND=y
@@ -6,3 +7,7 @@ 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
+CONFIG_PSA_WANT_KEY_TYPE_AES=y
+CONFIG_PSA_WANT_ALG_SHA_384=y
+CONFIG_PSA_WANT_KEY_TYPE_HMAC=y
+CONFIG_PSA_WANT_ALG_HMAC=y

diff --git a/tests/net/socket/tls_configurations/prj.conf b/tests/net/socket/tls_configurations/prj.conf
index 6e8c9e15c1c..3e6ea837b0c 100644
--- a/tests/net/socket/tls_configurations/prj.conf
+++ b/tests/net/socket/tls_configurations/prj.conf
@@ -35,13 +35,13 @@ CONFIG_ENTROPY_GENERATOR=y

-CONFIG_MBEDTLS_TLS_VERSION_1_2=n
-CONFIG_MBEDTLS_KEY_EXCHANGE_RSA_ENABLED=n
-CONFIG_MBEDTLS_MD=n
-CONFIG_MBEDTLS_RSA_C=n
-CONFIG_MBEDTLS_CIPHER_AES_ENABLED=n
-CONFIG_PSA_WANT_KEY_TYPE_AES=n
-CONFIG_PSA_WANT_ALG_CBC_NO_PADDING=n
+# CONFIG_MBEDTLS_TLS_VERSION_1_2=n
+# CONFIG_MBEDTLS_KEY_EXCHANGE_RSA_ENABLED=n
+# CONFIG_MBEDTLS_MD=n
+# CONFIG_MBEDTLS_RSA_C=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
@@ -51,3 +51,16 @@ CONFIG_PRINTK=y
+# CONFIG_NET_LOG=y
+# CONFIG_MBEDTLS_LOG_LEVEL_DBG=y
+# CONFIG_MBEDTLS_DEBUG=y
+#
+CONFIG_SHELL=y
+CONFIG_NET_SHELL=y
+CONFIG_NET_IPV4=y
+CONFIG_NET_TCP=y
+
+CONFIG_NET_CONFIG_SETTINGS=y
+CONFIG_NET_CONFIG_NEED_IPV4=y
+CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.168.1.xx"
+CONFIG_NET_CONFIG_PEER_IPV4_ADDR="192.168.1.xxx"
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
+CONFIG_NET_CONFIG_MY_IPV4_NETMASK="255.255.255.0"
+CONFIG_NET_CONFIG_MY_IPV4_GW="192.168.1.1"`

[carlescufi]

@rlubos should know

[rlubos]

The default configuration in that test suite for TLS 1.3 is enough to establish TLS 1.3 handshake (just confirmed that). Perhaps you're getting confused by the legacy version field which is set to 1.2 for backwards compability reasons? This shows in the wireshark for the Client Hello:

But the extension is present and version set to 1.3:

[rlubos]

Is offloaded sockets mandatory for TLS 1.3 in zephyr?

No, it was just used to simplify testing setup.

It clearly seems like some mbed TLS misconfiguration, I can't tell for sure what's missing/wrong though, I'm not that proficient with the new mbed TLS configuration options. One idea, one of these configs is missing perhaps?

CONFIG_MBEDTLS_TLS_SESSION_TICKETS=y
CONFIG_MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED=y
CONFIG_MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED=y

For some reason those were not specified in the test configuration files, but in the testcase.yaml.

[SanjayyyV]

Thanks for the suggestion but I have tried this as well. But I have been unable to succeed with the Signature algorithm extension. Would you be able to share the config files of yours and also the diff, if possible?

[rlubos]

I don't have any custom local changes, I just ran the tests/net/socket/tls_configurations/ defaults.

[SanjayyyV]

Oh, that's interesting. Do you test it using twister or just regular west build and flash?

[rlubos]

Twister