Disabling P2P-device MAC Address randomization for P2P persistent groups

Macrì Alberto amacri at tiscali.it
Tue Dec 29 10:19:01 EST 2020


The current versions of the nl80211 device drivers enable MAC 
randomization by default, so that, when wpa_supplicant creates the 
"P2P-Device" virtual interface, a randomized MAC address is used and 
this breaks the persistent P2P Group reuse when the "P2P-Device" virtual 
interface is recreated. A persistent P2P-GO group works correctly while 
wpa_supplicant is running. After restarting wpa_supplicant, it creates a 
new "P2P-device type" interface with a different (randomized) MAC 
address and the saved persistent group in the peer device becomes no 
more usable for reconnection: only a new persistent group can be 
established (through new authorization process), usable until 
wpa_supplicant is subsequently restarted.

The expected behaviour is that a reconnection to the previously saved 
group is possible also after restarting wpa_supplicant.

After experimenting a modification in wpa_supplicant so that it forces a 
fixed MAC address during the "P2P-Device" virtual interface creation, I 
performed some tests using an Android device as P2P Client and a Linux 
server running the modified wpa_supplicant: in such case the issue is 
overcome.

Can someone confirm that a change has to be done in wpa_supplicant in 
order to support such feature?

Thanks




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