wifi: mac80211: clear frame buffer to never leak stack

JIRA: https://issues.redhat.com/browse/RHEL-114889

commit 8af596e
Author: Johannes Berg <johannes.berg@intel.com>
Date:   Tue Jul 1 09:22:13 2025 +0200

    wifi: mac80211: clear frame buffer to never leak stack
    
    In disconnect paths paths, local frame buffers are used
    to build deauthentication frames to send them over the
    air and as notifications to userspace. Some internal
    error paths (that, given no other bugs, cannot happen)
    don't always initialize the buffers before sending them
    to userspace, so in the presence of other bugs they can
    leak stack content. Initialize the buffers to avoid the
    possibility of this happening.
    
    Suggested-by: Zhongqiu Han <quic_zhonhan@quicinc.com>
    Link: https://patch.msgid.link/20250701072213.13004-2-johannes@sipsolutions.net
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Author: jtornosm

net/mac80211/mlme.c

@@ -3934,6 +3934,9 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
+	if (frame_buf)
+		memset(frame_buf, 0, IEEE80211_DEAUTH_FRAME_LEN);
+
 	if (WARN_ON(!ap_sta))
 		return;