mac80211: accept key reinstall without changing anything

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commit fdf7cb4185 upstream.

When a key is reinstalled we can reset the replay counters
etc. which can lead to nonce reuse and/or replay detection
being impossible, breaking security properties, as described
in the "KRACK attacks".

In particular, CVE-2017-13080 applies to GTK rekeying that
happened in firmware while the host is in D3, with the second
part of the attack being done after the host wakes up. In
this case, the wpa_supplicant mitigation isn't sufficient
since wpa_supplicant doesn't know the GTK material.

In case this happens, simply silently accept the new key
coming from userspace but don't take any action on it since
it's the same key; this keeps the PN replay counters intact.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

...

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Johannes Berg 2017-09-05 14:54:54 +02:00 • committed by Ben Hutchings

parent c42ab77ec3

commit a0a8a11d16

1 changed files with 17 additions and 3 deletions

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net/mac80211/key.c

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