wifi: mac80211: do not use old MBSSID elements

When userspace brings down and deletes a non-transmitted profile,
it is expected to send a new updated Beacon template for the
transmitted profile of that multiple BSSID (MBSSID) group which
does not include the removed profile in MBSSID element. This
update comes via NL80211_CMD_SET_BEACON.

Such updates work well as long as the group continues to have at
least one non-transmitted profile as NL80211_ATTR_MBSSID_ELEMS
is included in the new Beacon template.

But when the last non-trasmitted profile is removed, it still
gets included in Beacon templates sent to driver. This happens
because when no MBSSID elements are sent by the userspace,
ieee80211_assign_beacon() ends up using the element stored from
earlier Beacon template.

Do not copy old MBSSID elements, instead userspace should always
include these when applicable.

Fixes: 2b3171c6fe0a ("mac80211: MBSSID beacon handling in AP mode")
Signed-off-by: Aloka Dixit <aloka.dixit@oss.qualcomm.com>
Link: https://patch.msgid.link/20251215174656.2866319-2-aloka.dixit@oss.qualcomm.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index b51c2c8584ae09dab745c9b0972d3a43ede05676..c81091a5cc3a33bea9a814ce3323aaa38447dd3e 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1345,7 +1345,6 @@ ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
 
        size = sizeof(*new) + new_head_len + new_tail_len;
 
-       /* new or old multiple BSSID elements? */
        if (params->mbssid_ies) {
                mbssid = params->mbssid_ies;
                size += struct_size(new->mbssid_ies, elem, mbssid->cnt);
@@ -1355,15 +1354,6 @@ ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
                }
                size += ieee80211_get_mbssid_beacon_len(mbssid, rnr,
                                                        mbssid->cnt);
-       } else if (old && old->mbssid_ies) {
-               mbssid = old->mbssid_ies;
-               size += struct_size(new->mbssid_ies, elem, mbssid->cnt);
-               if (old && old->rnr_ies) {
-                       rnr = old->rnr_ies;
-                       size += struct_size(new->rnr_ies, elem, rnr->cnt);
-               }
-               size += ieee80211_get_mbssid_beacon_len(mbssid, rnr,
-                                                       mbssid->cnt);
        }
 
        new = kzalloc(size, GFP_KERNEL);