delaying Michael MIC error reports by a random amount of time between 0 and
60 seconds if multiple Michael MIC failures are detected with the same PTK
(i.e., the Authenticator does not rekey PTK on first failure report). This
is disabled by default and can be enabled with a build option
CONFIG_DELAYED_MIC_ERROR_REPORT=y in .config.
This may help in making a chopchop attack take much longer time by forcing
the attacker to wait 60 seconds before knowing whether a modified frame
resulted in a MIC failure.
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.
