Enabling the TLS layer to get a HTTPS connection going.

[Tudor B.]

7343.nrf7002dk_nrf5340_cpuapp_ns.conf3124.prj.confHello everyone.

WE're trying to make a https connection with google.com and execute a GET request.

Wifi connection is working; DHCP seems to be working (my personal assumption given the log message we get: "Resolved: [(1, 1, 6, '', ('142.250.201.206', 443))]" which indicates that getaddrinfo() works); but when trying to initiate the socket via TLS, something strange happens: we get the error "OSError: 109".

Inserting some debug prints inside subsys/net/lib/sockets/, we found the culprit to be the function "int zsock_setsockopt_ctx(struct net_context *ctx, int level, int optname, const void *optval, socklen_t optlen)".

The function call that triggers error 109 is:  res = setsockopt(socket->ctx, SOL_TLS, TLS_PEER_VERIFY, &verify, sizeof(verify));

No matter what other option we try to set via setsockopt(), it will fail with the 109 error since the implementation for setsockopt() is somehow set to sockets_inet.c (whose implementation does not recognise SOL_TLS as a valid in its switches) instead of sockets_tls.c (which has handling for SOL_TLS in its switches). My personal hunch is that the config options set in the project are somehow wrong. Can someone please take a look over our .conf files? Maybe we can find the culprit. :)

We can provide any extra code snippets that are necessary for debugging and/ or run any tests. Have a great day and hope to hear from you soon!

[Håkon Alseth]

Hi,

 

I used net/https_client for this exercise.

You need to download r1.pem from here: https://pki.goog/repository/

 

Place this in certs/ folder, and make sure that you change the file in CMakeLists.txt, change the domain in kconfig, and add the required configurations in the board .conf file:

diff --git a/samples/net/https_client/CMakeLists.txt b/samples/net/https_client/CMakeLists.txt
index 2a937786ed..39276fd2e2 100644
--- a/samples/net/https_client/CMakeLists.txt
+++ b/samples/net/https_client/CMakeLists.txt
@@ -14,7 +14,7 @@ set(gen_dir ${CMAKE_CURRENT_BINARY_DIR}/certs)
 zephyr_include_directories(${gen_dir})
 generate_inc_file_for_target(
     app
-    cert/DigiCertGlobalG2.pem
+    cert/r1.pem
     ${gen_dir}/DigiCertGlobalG2.pem.inc
     )
 
diff --git a/samples/net/https_client/Kconfig b/samples/net/https_client/Kconfig
index 90ad33f42e..bb22e82794 100644
--- a/samples/net/https_client/Kconfig
+++ b/samples/net/https_client/Kconfig
@@ -15,7 +15,7 @@ config SAMPLE_TFM_MBEDTLS
 
 config HTTPS_HOSTNAME
        string "HTTPS hostname"
-       default "example.com"
+       default "google.com"
 
 endmenu
 
diff --git a/samples/net/https_client/boards/nrf7002dk_nrf5340_cpuapp_ns.conf b/samples/net/https_client/boards/nrf7002dk_nrf5340_cpuapp_ns.conf
index 9eb362cb16..8366313af8 100644
--- a/samples/net/https_client/boards/nrf7002dk_nrf5340_cpuapp_ns.conf
+++ b/samples/net/https_client/boards/nrf7002dk_nrf5340_cpuapp_ns.conf
@@ -69,3 +69,20 @@ CONFIG_MBEDTLS_TLS_LIBRARY=y
 CONFIG_TFM_PROFILE_TYPE_SMALL=y
 CONFIG_PM_PARTITION_SIZE_TFM_SRAM=0xc000
 CONFIG_PM_PARTITION_SIZE_TFM=0x20000
+
+CONFIG_MBEDTLS_SSL_SERVER_NAME_INDICATION=y
+CONFIG_MBEDTLS_SSL_RENEGOTIATION=y
+CONFIG_MBEDTLS_SSL_MAX_FRAGMENT_LENGTH=y
+CONFIG_MBEDTLS_SSL_SESSION_TICKETS=y
+CONFIG_PSA_WANT_RSA_KEY_SIZE_4096=y
+CONFIG_MBEDTLS_MPI_MAX_SIZE=512
+
+CONFIG_LOG=y
+CONFIG_MBEDTLS_DEBUG=y
+CONFIG_MBEDTLS_SSL_DEBUG_ALL=y
+CONFIG_MBEDTLS_LOG_LEVEL_DBG=y
+CONFIG_MBEDTLS_DEBUG_C=y
+CONFIG_MBEDTLS_DEBUG_LEVEL=4
+# Handle the large influx of prints
+CONFIG_LOG_BUFFER_SIZE=16384
+CONFIG_LOG_BACKEND_UART=y

I also need to add CONFIG_NET_IPV6=n due to a local network issue at my end.

 

Kind regards,

Håkon

[Tudor B.]

There are many options and suboptions in the link you sent me. Which one is the correct one?

When attempting to get it working, I got r1.der and then created r1.der.inc. But I'm not sure which option I chose.

[Håkon Alseth]

This one:

 

Kind regards,

Håkon

[Tudor B.]

Thank you! Sadly, when I add those config options, I get a DNS error:
DNS Error: 536969132

Without them, DNS successfully resolves google.com:
Resolved: [(1, 1, 6, '', ('142.250.180.206', 443))]

[Håkon Alseth]

Hi,

 

Could you try with https_client first, to see if this works there?

Add the cmd's (assuming WPA2) to store your SSID like this:

wifi_cred add -s SSID -k 1 -p PASSWORD
wifi_cred auto_connect

 

Kind regards,

Håkon

[Tudor B.]

Hey there Håkon,

I tried those commands, but I had to alter them a bit to get them to work on SDK v3.0.0. More specifically:
wifi cred add -s SSID -k 1 -p PASSWORD
wifi cred auto_connect

Also, this is my log from running them:

uart:~$ wifi cred auto_connect
uart:~$
uart:~$
uart:~$
uart:~$
uart:~$
--- 50 messages dropped ---
00 00 --- 67 messages dropped ---
01 17 00 04 17 d7 00 8a c0 0c 00 01 00 01 00 00 00 f7 00 10 26 00 14 06 3a 00 00 21 00 00 00 00 17 3e 2e 65 c0 0c 00 1c 00 01 00
uart:~$
Sent 61 bytes
Received 318 bytes

> HTTP/1.1 200 OK

Finished, closing socket.
Disconnected
Network connectivity lost
Disconnected from the network
uart:~$
uart:~$
uart:~$

[Tudor B.]

Also worth noting: by taking the https_client sample's config as a 1-to-1 reference, we overflow by ~130kb (region `FLASH' overflowed by 138084 bytes). I assume this is to the more "generous" sizes in the example. Are they truly necessary?