wifi: mac80211: Check for MLE before appending in Authentication frame

wifi: mac80211: Check for MLE before appending in Authentication frame

Currently, in MLO connections, userspace constructs most of the
Authentication frame body, excluding the Multi-Link element (MLE),
which mac80211 appends later in ieee80211_send_auth(). At present,
mac80211 always adds the MLE itself, since userspace
(e.g. wpa_supplicant) does not yet include it.

However, for new authentication protocols such as Enhanced Privacy
Protection Key Exchange (EPPKE), as specified in
"IEEE P802.11bi/D3.0 section 12.16.9", the MLE must be included in
userspace so that the Message Integrity Code (MIC) can be computed
correctly over the complete frame body. Table 9-71 specifies that
the MIC is mandatory. If mac80211 appends the MLE again, the
Authentication frame becomes invalid.

Add a check in ieee80211_send_auth() to detect whether the MLE is
already present in the Authentication frame body before appending.
Skip the append if the MLE exists, otherwise add it as before.

Signed-off-by: Kavita Kavita <kavita.kavita@oss.qualcomm.com>
Link: https://patch.msgid.link/20260114111900.2196941-7-kavita.kavita@oss.qualcomm.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>