Can't get Just Works bonding between nRF5 SDK and nRF Connect SDK to work

RE: Can't get Just Works bonding between nRF5 SDK and nRF Connect SDK to work

Simonr — Thu, 10 Mar 2022 11:44:10 GMT

I assume you haven't set the two devices to bond using the same security levels. What kind of pairing are you looking to do? LESC Just Works, or something more secure? Implementing LESC has already been discussed in detail in this case, where they are eventually able to enable LESC paring for the peripheral_uart example project. Please give it a read and see if you missed any crucial steps.

Best regards,

Simon

RE: Can't get Just Works bonding between nRF5 SDK and nRF Connect SDK to work

tyana — Wed, 09 Mar 2022 13:56:14 GMT

Hello! Sorry it took this long to reply.

For the sake of experiment I took a proper clean peripheral_uart example from NCS 1.8.0 and also added bonding to ble_app_uart_c example from nRF5 SDK 15.3.0 basically by copying parts of ble_app_hrs_c into it.

A simple bonding between these works, but LESC doesn't: with sec_param.lesc set to 1 in peer_manager_init in ble_app_uart_c and the respective conn_auth_callbacks set to NULL in peripheral_uart, the "security failed" with UNSPECIFIED error code at the peripheral device persist; judging by this diagram of LESC bonding, it fails at LESC authentication stage 1 just after DHKEY request is handled by the central, since no requests come after that.

I want to get LESC to work but can't imagine what else is required for it to work.

I'm attaching the modified ble_app_uart_c project/source if you would like to reproduce this behavior.

devzone.nordicsemi.com/.../ble_5F00_app_5F00_uart_5F00_c_5F00_with_5F00_lesc_5F00_bonding.zip

RE: Can't get Just Works bonding between nRF5 SDK and nRF Connect SDK to work

Simonr — Thu, 17 Feb 2022 09:49:33 GMT

Have you enabled the CONFIG_BT_NUS_SECURITY_ENABLED config in the peripheral_uart function? Unfortunately the UNSPECIFIED error could be a lot of things, as it points to that pairing failed, but that the reason could not be specified. For the AUTH_REQUIREMENT error, that points to the requested security level not being reached, which means the central and peripheral is likely not requesting the same security levels.

Best regards,

Simon

RE: Can't get Just Works bonding between nRF5 SDK and nRF Connect SDK to work

tyana — Wed, 16 Feb 2022 11:48:58 GMT

Hello!

The conn_auth_callbacks that should be set as NULL are all set as NULL at peripheral.

I can't say for sure my nRF5 SDK project is based on any example, but when I was adding peer manager to the project I used HRS Central example as a reference. So I just copied peer manager init (but with security settings as in my post above) and pm_evt_handler from that and added a pm_conn_secure call to the discovery complete event in my service event handler.

With that, I got BT_SECURITY_ERR_AUTH_REQUIREMENT error on the peripheral.

I've figured out the NRF_ERROR_INVALID_ADDR that appeared when I tried to have LESC, I didn't have it enabled in peer manager (didn't set PM_LESC_ENABLED). This is no longer as issue.

Now when I set sec_param.lesc to true on the central, I get BT_SECURITY_ERR_UNSPECIFIED error on the peripheral instead.

RE: Can't get Just Works bonding between nRF5 SDK and nRF Connect SDK to work

Simonr — Mon, 14 Feb 2022 07:37:10 GMT

sd_ble_gap_sec_params_reply returning an NRF_ERROR_INVALID_ADDR means that an invalid pointer has been supplied. Have you seen the message sequence chart for "just works Bonding"?

How does the peripheral side's conn_auth_callbacks look? Have you made sure to set passkey_display, passkey_confirm, and pairing_confim to NULL in your conn_auth_callbacks? What central example application is your nRF5 SDK central project based on exactly?

Best regards,

Simon