SMP Bluetooth Authentication Inusfficient

[LukeC]

I am using the NCS (2.0.2) SMP SRVR example with the bt-overlay.

I can connect via Bluetooth, but once I start the DFU update via nRF Connect I get an "Authentication is Insufficient" error 

See the screenshot of the app below.

Does the SMP protocol over BLE require some extra security settings?

[Vidar Berg]

Hello,

You should only get this authentication error if you have CONFIG_MCUMGR_SMP_BT_AUTHEN is enabled in your project. However,  this symbol is disabled by default in the bt overlay file: https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1-branch/samples/subsys/mgmt/mcumgr/smp_svr/overlay-bt.conf#L9, so I would not expect this error with the original sample code.

Could you please double check the .config output to verify that it is not enabled in your build?

Here is where the SMP characteristic permission levels gets set:

https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1-branch/subsys/mgmt/mcumgr/smp_bt.c#L281 

Best regards,

Vidar

[LukeC]

I also believe you need to increase the following from 10 to something higher for the SMP example: 

CONFIG_BT_L2CAP_TX_BUF_COUNT