forked from Minki/linux
c49a8682fc
Problem: The Linux Bluetooth stack yields complete control over the BLE connection interval to the remote device. The Linux Bluetooth stack provides access to the BLE connection interval min and max values through /sys/kernel/debug/bluetooth/hci0/ conn_min_interval and /sys/kernel/debug/bluetooth/hci0/conn_max_interval. These values are used for initial BLE connections, but the remote device has the ability to request a connection parameter update. In the event that the remote side requests to change the connection interval, the Linux kernel currently only validates that the desired value is within the acceptable range in the Bluetooth specification (6 - 3200, corresponding to 7.5ms - 4000ms). There is currently no validation that the desired value requested by the remote device is within the min/max limits specified in the conn_min_interval/conn_max_interval configurations. This essentially leads to Linux yielding complete control over the connection interval to the remote device. The proposed patch adds a verification step to the connection parameter update mechanism, ensuring that the desired value is within the min/max bounds of the current connection. If the desired value is outside of the current connection min/max values, then the connection parameter update request is rejected and the negative response is returned to the remote device. Recall that the initial connection is established using the local conn_min_interval/conn_max_interval values, so this allows the Linux administrator to retain control over the BLE connection interval. The one downside that I see is that the current default Linux values for conn_min_interval and conn_max_interval typically correspond to 30ms and 50ms respectively. If this change were accepted, then it is feasible that some devices would no longer be able to negotiate to their desired connection interval values. This might be remedied by setting the default Linux conn_min_interval and conn_max_interval values to the widest supported range (6 - 3200 / 7.5ms - 4000ms). This could lead to the same behavior as the current implementation, where the remote device could request to change the connection interval value to any value that is permitted by the Bluetooth specification, and Linux would accept the desired value. Signed-off-by: Carey Sonsino <csonsino@gmail.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> |
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| .. | ||
| bnep | ||
| cmtp | ||
| hidp | ||
| rfcomm | ||
| 6lowpan.c | ||
| a2mp.c | ||
| a2mp.h | ||
| af_bluetooth.c | ||
| amp.c | ||
| amp.h | ||
| ecdh_helper.c | ||
| ecdh_helper.h | ||
| hci_conn.c | ||
| hci_core.c | ||
| hci_debugfs.c | ||
| hci_debugfs.h | ||
| hci_event.c | ||
| hci_request.c | ||
| hci_request.h | ||
| hci_sock.c | ||
| hci_sysfs.c | ||
| Kconfig | ||
| l2cap_core.c | ||
| l2cap_sock.c | ||
| leds.c | ||
| leds.h | ||
| lib.c | ||
| Makefile | ||
| mgmt_util.c | ||
| mgmt_util.h | ||
| mgmt.c | ||
| sco.c | ||
| selftest.c | ||
| selftest.h | ||
| smp.c | ||
| smp.h | ||