If a STA reassociates and changes key_mgmt (e.g., from WPA-PSK to WPS),
hostapd needs to reset some of the existing STA and WPA state machine
variables to allow correct processing for the new association.
Added a new configuration option, wpa_ptk_rekey, that can be used to
enforce frequent PTK rekeying, e.g., to mitigate some attacks against TKIP
deficiencies. This can be set either by the Authenticator (to initiate
periodic 4-way handshake to rekey PTK) or by the Supplicant (to request
Authenticator to rekey PTK).
With both wpa_ptk_rekey and wpa_group_rekey (in hostapd) set to 600, TKIP
keys will not be used for more than 10 minutes which may make some attacks
against TKIP more difficult to implement.
Previous version could have allowed a broken client to complete WPA (or
WPA2) authentication even if the selected proto was not enabled in hostapd
configuration.
