On Mon, Jan 14, 2008 at 06:18:18AM -0300, Werner Almesberger wrote: > OpenMoko has recently obtained its own OUI, so we can now (finally :-) > assign proper MAC addresses. In GTA02, the following items needs one: > > - BlueTooth > - WLAN > - Ethernet over USB. Two of them, one for the device and one for the host: > http://bugzilla.openmoko.org/cgi-bin/bugzilla/show_bug.cgi?id=1023 > > WLAN hardware brings its own MAC address, so we can just use that one. > BT comes with a set of MAC addresses from the vendor (en bloc, so we'd > still have to handle the assignment of individual addresses ourselves), > but we can choose to ignore them. (Well, politely return them.) > > Now I'd like to get a sanity check for the assignment plan: > > I was thinking of assigning three MAC addresses to each device. Can > anyone think of any other popular protocol sitting on top of something > else that would expect to get its own MAC address, like EoUSB does ? > > Now, how do we assign them ? There are 24 bits to play with. I was > thinking of making allocations in blocks from which the factory then > picks addresses randomly. I think a block size around 16-18 bits > should do nicely. > > Does anyone see a problem with using consecutive addresses for the same > device ? E.g., BT = base, EoUSB.device = base+1, EoUSB.host = base+2
No, I cannot think of any problems with that. In fact, this is what multi-port ethernet cards seem to do, too. Now sure, people can determine that a neo1973 is used by looking at the OUI prefix, and then if they have the Wifi MAC, they can predict the bluetooth or ethernet-over-usb MAC. The latter is of no use since it's only private to the pc-neo USB link anyway. I have very little knowledge of the bluetooth security world. I don't think any of it relies on unpredictable mac addresses, though. As soon as a device talks, you would see its mac address anyway. Marcel: Do you see any problems if the Bluetooth MAC address can be predicted if somebody has seen the WiFI MAC Address (or vice versa)? -- - Harald Welte <[EMAIL PROTECTED]> http://openmoko.org/ ============================================================================ Software for the world's first truly open Free Software mobile phone
