[nRF Connect SDK]Force to make pairing(bonding)

[Tim Hwang]

Target nRF52832(nrf52dk_nrf52832)
SDK NCS v2.0.0

I'm testing NCS 2.0 with Android 12.

Making pairing with Android, I call two API when connected.

bt_set_bondable(true);
bt_conn_set_security(conn, BT_SECURITY_L4);

It worked well so far (under Android 11)

BTW Android 12 make trouble security level 1 error.


[log]
00> HS connected
00> HS Connected 4A:B4:CA:22:85:2D (random)
00> Connection parameters updated.
00> interval: 6, latency: 0, timeout: 500
00> Conn params updated: interval 7 ms, latency 0, timeout: 5000 ms
00> Security failed: 4A:B4:CA:22:85:2D (random) level 1 err 2
00> Disconnected: 4A:B4:CA:22:85:2D (random) (reason 34)

Can I have another option to make pairing automatically?

[Tim Hwang]

Thanks for updating.

1) Don't call bt_conn_set_security() on connected() callback, but start it for instance after 100ms after connected() callback or (for test) just use a button to call bt_conn_set_security() after connection is established.

-> I test it but 1000ms delay was not effective. Please see source code attached
main.c
k_work_reschedule(&auth_work, K_MSEC(1000));

8081.peripheral_uart.7z


2) Additional test

13Sep2022_B.zip

You can find full text in readme.txt and snoop log in attached 

I also made same case in MTK. and I am going to make case Qualcomm within a few days.
We don't have another BLE sample that initiate (pairing) bonding so that I cannot tell who made this issue.

*Failure case
#3157: Android send pairing request
-> But Nordic BLE did not send pairing response.

*Success case
#3255: Android send pairing request
#3257: Nordic BLE send pairing response.

It seems that there are no differences between #3255 and #3257 packet.
We can reproduce this issue once when Bluetooth turned on in Android 12.
Once pairing is made, Android can connect to BLE with security level 4.

Please give me your opinion.

[Kenneth]

Kenneth said:

From the on-air sniffer I can find a lot of data is missing, so if possible try to move phone, device and sniffer closer together to ensure that the sniffer log is more complete.

I didn't find a new on-air sniffer log in your latest update?

Kenenth

[Tim Hwang]

I cannot get full sniff log due to security. So I provide you bluetooth snoop log.
You can see the log with comprobe tool.

https://drive.google.com/file/d/1O2GU5AEvjl1B0aN3DnjNBewGMneb4Ywv/view?usp=sharing

Change file extension *.cfa

I'm wondering if you could tell me Android pairing request message have not enough to make bonding from log.
Then we will argue to MTK and Qualcomm HQ about it.

Thanks.

[Kenneth]

Please zip the .caf file, if you are able to retrieve the LTK from the snoop log, then you can insert the LTK in an on-air snifer log to decrypt the data afterwards: https://infocenter.nordicsemi.com/topic/ug_sniffer_ble/UG/sniffer_ble/action_bonded.html 

Kenneth