Setting IO Capabilities with NCS

[nrbrook]

I've tried searching for some documentation on pairing IO capabilities with NCS/Zephyr but can't find any. I'm trying to modify the peripheral_hids_keyboard example to use "just works" pairing (no input no output device). Looking at the docs for bt_conn_auth_cb I thought simply removing the passkey_* and pairing_confirm callbacks would be sufficient, but pairing fails and I get "Security failed: <addr> (public) level 1 err 4" in the console output. The only reference I can see to IO capabilities is the "CONFIG_BT_SMP_ENFORCE_MITM" option (which is enabled in the example):

"With this option enabled, the Security Manager will set MITM option in the Authentication Requirements Flags whenever local IO Capabilities allow the generated key to be authenticated."

But I can't find any docs that detail how to specify those local IO capabilities.

What else do I need to do? Where is the documentation for this?

[Mttrinh]

Hi,

You can read more about it here.

[nrbrook]

That suggests I was correct in thinking that setting passkey_* and pairing_confirm callbacks to NULL would be sufficient, but then why does pairing fail with error 4? Error 4 is:

/** The requested security level could not be reached. */
	BT_SECURITY_ERR_AUTH_REQUIREMENT,

[nrbrook]

Hi, do you have any more suggestions?

[Mttrinh]

Hi,

It might be related to the CONFIG_BT_HIDS_DEFAULT_PERM_RW_ENCRYPT. 

Can you try setting this to "n" in addition to the changes you already made and see what happens?

[nrbrook]

No, unfortunately the result is the same