It looks like some Windows NDIS drivers (e.g., Intel) do not clear the
PMKID list even when wpa_supplicant explicitly sets the list to be
empty. In such a case, the driver ends up trying to use PMKSA caching
with the AP and wpa_supplicant may not have the PMK that would be needed
to complete 4-way handshake.
RSN processing already had some code for aborting PMKSA caching by
sending EAPOL-Start. However, this was not triggered in this particular
case where the driver generates the RSN IE. With this change, this case
is included, too, and the failed PMKSA caching attempt is cleanly
canceled and wpa_supplicant can fall back to full EAP authentication.
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.
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.
wpa_sm_set_config() can be called even if the network block does not
change. However, the previous version ended up calling
pmksa_cache_notify_reconfig() every time and this cleared the network
context from PMKSA cache entries. This prevented OKC from ever being used.
Do not call pmksa_cache_notify_reconfig() if the network context remains
unchanged to allow OKC to be used.
Function 'wpa_sm_set_config' used the argument 'config' as the network
context which is a pointer to a local variable of the function
'wpa_supplicant_rsn_supp_set_config'.
This is one reason why no proactive key was generated. This network
context never matched with the network context saved in the pmksa cache
entries.
The structure 'rsn_supp_config' has already a member 'network_ctx' which
is now filled in by this patch with 'ssid'.
Signed-off-by: Michael Bernhard <michael.bernhard@bfh.ch>
This avoids getting stuck in state where wpa_supplicant has canceled scans,
but the driver is actually in disassociated state. The previously used code
that controlled scan timeout from WPA module is not really needed anymore
(and has not been needed for past four years since authentication timeout
was separated from scan request timeout), so this can simply be removed to
resolved the race condition. As an extra bonus, this simplifies the
interface to WPA module.
[Bug 261]
Transition. This fixes a potential issue where an incorrectly behaving AP
could send a group key update using the old (now invalid after reassociate)
PTK. This could also happen if there is a race condition between reporting
received EAPOL frames and association events.
