Windows 7 uses incorrect way of figuring out AP's WPS capabilities by
acting as a Registrar and using M1 from the AP. The config methods
attribute in that message is supposed to indicate only the configuration
method supported by the AP in Enrollee role, i.e., to add an external
Registrar. For that case, PBC shall not be used and as such, the
PushButton config method is removed from M1 by default. If pbc_in_m1=1
is included in the configuration file, the PushButton config method is
left in M1 (if included in config_methods parameter) to allow Windows 7
to use PBC instead of PIN (e.g., from a label in the AP).
An optional parameter, p2p_dev_addr, can now be given to WPS_PBC
command on P2P GO to indicate that only the P2P device with the
specified P2P Device Address is allowed to connect using PBC. If
any other device tries to use PBC, a session overlap is indicated
and the negotiation is rejected with M2D. The command format for
specifying the address is "WPS_PBC p2p_dev_addr=<address>", e.g.,
WPS_PBC p2p_dev_addr=02:03:04:05:06:07
In addition, show the PBC session overlap indication as a WPS failure
event on an AP/GO interface. This particular new case shows up as
"WPS-FAIL msg=4 config_error=12".
Prior to commit 6195adda9b the sm->user
dereference did not exist here. While this is in practice non-NULL,
better use more defensive construction here to avoid NULL pointer
dereference should this ever change.
In theory, this should not really be needed, but Windows 7 uses
Registrar mode to probe AP's WPS capabilities before trying to use
Enrollee and fails if the AP does not allow that probing to happen.
This allows the AP to start as an Enrollee and send M1, but refuse
to continue beyond that (M3 will not be sent if AP PIN is not known).
