The group key state machine needs to be re-initialized with possible
updated GTK length when restarting WPA (e.g., when WPS was used to
reconfigure the AP).
Previously, we would have allowed both the WPA and RSN EAPOL-Key
types to be used regardless of whether the association is using
WPA or RSN/WPA2. This shouldn't result in any significant problems
on the Authenticator side, but anyway, we should check the type and
ignore the EAPOL-Key frames that used unexpected type.
IEEE 802.11r KDF uses key length in the derivation and as such, the PTK
length must be specified correctly. The previous version was deriving
using 512-bit PTK regardless of the negotiated cipher suite; this works
for TKIP, but not for CCMP. Update the code to use proper PTK length
based on the pairwise cipher.
This fixed PTK derivation for both IEEE 802.11r and IEEE 802.11w (when
using AKMP that specifies SHA-256-based key derivation). The fixed
version does not interoperate with the previous versions. [Bug 307]
dot11RSNAConfigGroupUpdateTimeOut and
dot11RSNAConfigPairwiseUpdateTimeOut MIB variables were only used in
draft versions of IEEE 802.11i, so rename these in order not to use
confusing name here.
Replaced EAPOL-Key timeout to use following timeouts (in
milliseconds): 100,1000,1000,1000 (this was 1000,1000,1000,0). There
is no point in sending out the final EAPOL-Key frame which would be
immediately followed by disconnection. After the change to allow
response to any pending EAPOL-Key frame, it is fine to send the first
retransmission quickly to avoid long wait in cases where Supplicant
did not receive the first frame for any reason. The new sequence will
still provide 3.1 seconds of time to get any response frame, so this
does not reduce the previous time.
Accept response to any pending request, not just the last one. This
gives the Supplicant more time to reply since hostapd will now allow up
to three seconds for the reply to the first EAPOL-Key frame transmission
(and two seconds for the first retry and one second for the last) while
the previous version invalidated any old request immediately when
sending a retransmitted frame.
If the Supplicant replies to more than one request, only the first reply
to arrive at the Authenticator will be processed. As far as the
Supplicant is concerned, this behavior does not differ from the previous
one except for being less likely to cause unneeded retransmissions of
EAPOL-Key frames.
This can help in cases where power saving is used when the group key is
rekeyed or when there is excessive traffic on the channel that can delay
(or drop) EAPOL-Key frames.
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.
This adds WPS support for both hostapd and wpa_supplicant. Both programs
can be configured to act as WPS Enrollee and Registrar. Both PBC and PIN
methods are supported.
Currently, hostapd has more complete configuration option for WPS
parameters and wpa_supplicant configuration style will likely change in
the future. External Registrars are not yet supported in hostapd or
wpa_supplicant. While wpa_supplicant has initial support for acting as
an Registrar to configure an AP, this is still using number of hardcoded
parameters which will need to be made configurable for proper operation.
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.
We need to cancel the group key update for a STA if a reauthentication
request is received while the STA is in pending group key update. When
canceling the update, we will also need to make sure that the PTK Group Key
state machine ends up in the correct state (IDLE) to allow future updates
in case of WPA2.
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 updates management frame protection to use the assocition ping process
from the latest draft (D6.0) to protect against unauthenticated
authenticate or (re)associate frames dropping association.
