Samples: Bluetooth: peripheral_hids fails to set security (Android central)

[Thalley]

Describe the bug The sample has

    if (bt_conn_set_security(conn, BT_SECURITY_L2)) {
        printk("Failed to set security\n");
    }

in the connected callback, but it seems to fail to do encryption when connected to an Android Phone.

To Reproduce

1. Build the sample with CONFIG_SAMPLE_BT_USE_AUTHENTICATION=n
2. Flash the sample
3. Connect an Android Phone
4. See error

Expected behavior Expect the security to be set to level 2.

Impact Depends. If it was something that used to work and stopped working at some point, it is caused by a change in the stack that may not be documented.

Logs and console output

Advertising successfully started
Connected 51:9E:D8:12:F4:4F (random)
Security failed: 51:9E:D8:12:F4:4F (random) level 1 err (2)
Disconnected from 51:9E:D8:12:F4:4F (random), reason 0x13 

Environment (please complete the following information):

• Commit SHA or Version used: afce5329f772a4306af699c7a06efddf93cadca0

Additional context Tested on a nRF5340 DK for the Zephyr sample with the hci_ipc sample with the nrf5340_cpunet_iso-bt_ll_sw_split.conf overlay for the network core. Tested on an Pixel 8 running Android 14

[alwa-nordic]

Would you be able to get an HCI pcap? Would be great if you could test with an older version of Zephyr too.

[Thalley]

Would you be able to get an HCI pcap? Would be great if you could test with an older version of Zephyr too.

Trying to, but I have some issues getting the log with btmon. Not sure what the cause is yet.

[jhedberg]

Shouldn't the bt_conn_set_security() call be excluded when CONFIG_SAMPLE_BT_USE_AUTHENTICATION=n? I.e. is the sample simply missing an #ifdef?

[Thalley]

Shouldn't the bt_conn_set_security() call be excluded when CONFIG_SAMPLE_BT_USE_AUTHENTICATION=n? I.e. is the sample simply missing an #ifdef?

Security level 2 can be done without authentication

[jhedberg]

Security level 2 can be done without authentication

Right, and I checked that smp.c should correctly fall back to just-works when there are no authentication callbacks registered.

[Thalley]

Security level 2 can be done without authentication

Right, and I checked that smp.c should correctly fall back to just-works when there are no authentication callbacks registered.

Indeed. I've tested the same with the BT shell and works fine there, so I believe the issue is that it is being called in the connected callback, or related to timing