A bug just got reported as a result of this for mac80211 drivers.
https://bugzilla.redhat.com/show_bug.cgi?id=459399
The basic problem is that since taking the device down clears the keys
from the driver on many mac80211-based cards, and since the mode gets
set _after_ the keys have been set in the driver, the keys get cleared
on a mode switch and the resulting association is wrong. The report is
about ad-hoc mode specifically, but this could happen when switching
from adhoc back to managed mode.
IEEE 802.11w/D6.0 defines new AKMPs to indicate SHA256-based algorithms for
key derivation (and AES-CMAC for EAPOL-Key MIC). Add support for using new
AKMPs and clean up AKMP processing with helper functions in defs.h.
This adds most of the new frame format and identifier definitions from IEEE
802.11w/D6.0. In addition, the RSN IE capability field values for MFP is
replaced with the new two-bit version with MFPC (capable) and MFPR
(required) processing.
Depending on how the driver implements IBSS searching and creation, it
may need to perform one or more scans before successfully completing the
association operation. Therefore, increase the timeout for IBSS
association operations so that the supplicant doesn't interrupt the
driver as much.
