Thanks Marcel, that looks good to me. I agree it's more than the customer asked for, but it's completely transparent :) On Wed, Mar 25, 2020 at 2:19 PM Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote: > > Hi Alain, > > >> I suspect we'd want bluetoothd to have a configuration that can enforce a more secure posture. > >> > >> Unfortunately when the command isn't supported, the platform is left between a rock and hard place... There isn't much we can do but to block the use of Bluetooth if the platform requires a more secure posture. > > > > so if the BR/EDR part is not up to the policy that the host requires, we could still configure the LE part. BlueZ is set up in this way that you can run a dual-mode controller as just a LE controller. > > > > I would also opt for the kernel just tells us what options it have. Then at least we can provide some feedback to the end-user on why Bluetooth is not available or why only selected features are available. > > what about something like this: > > +Read Security Features Command > +============================== > + > + Command Code: 0x0048 > + Controller Index: <controller id> > + Command Parameters: > + Return Parameters: Security_Data_Length (2 Octets) > + Security_Data (0-65535 Octets) > + > + This command is used to retrieve the supported security features > + by the controller or the kernel. > + > + The Security_Data_Length and Security_Data parameters provide > + a list of security settings, features and information. It uses > + the same format as EIR_Data, but with the namespace defined here. > + > + Data Type Name > + -------------------- > + 0x01 Flags > + 0x02 Max Encryption Key Size (BR/EDR) > + 0x03 Max Encryption Key Size (LE) > + 0x04 Encryption Key Size enforcement (BR/EDR) > + 0x05 Encryption Key Size enforcement (LE) > + 0x06 ECDH Public Key validation (BR/EDR) > + 0x07 ECDH Public Key validation (LE) > + > + > + Max Encryption Key Size (BR/EDR and LE) > + > + When the field is present, then it provides 1 Octet value > + indicating the max encryption key size. If the field is not > + present, then it is unknown what the max encryption key > + size of the controller or host is in use. > + > + Encryption Key Size Enforcement (BR/EDR and LE) > + > + When the field is present, then it provides 1 Octet value > + indicating the min encryption key size that is enforced by > + the controller or host. If the field is not present, then > + it is unknown what the controller or host are enforcing. > + > + ECDH Public Key validation (BR/EDR and LE) > + > + When the field is present, then it provides 1 Octet value > + indicating if public key validation is in use (0x01) or not > + available (0x00). If the field is not present, then it is > + unknown if the controller or host are validating public keys. > + > + This command generates a Command Complete event on success or > + a Command Status event on failure. > + > + Possible errors: Invalid Parameters > + Invalid Index > > Maybe this is overkill, but it would give us some flexible way of having the kernel tell us what is supported. Then bluetoothd can decide to power a controller or parts of a controller. > > Regards > > Marcel >
