From 283fc9e44ff5b5ac967439b4951b80bd4299f4e4 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 5 May 2026 15:15:34 +0200 Subject: [PATCH] wifi: mac80211: remove station if connection prep fails If connection preparation fails for MLO connections, then the interface is completely reset to non-MLD. In this case, we must not keep the station since it's related to the link of the vif being removed. Delete an existing station. Any "new_sta" is already being removed, so that doesn't need changes. This fixes a use-after-free/double-free in debugfs if that's enabled, because a vif going from MLD (and to MLD, but that's not relevant here) recreates its entire debugfs. Cc: stable@vger.kernel.org Fixes: 81151ce462e5 ("wifi: mac80211: support MLO authentication/association with one link") Reviewed-by: Miriam Rachel Korenblit Link: https://patch.msgid.link/20260505151533.c4e52deb06ad.Iafe56cec7de8512626169496b134bce3a6c17010@changeid Signed-off-by: Johannes Berg --- net/mac80211/mlme.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index 298ebff6bbf8..0a0f27836d57 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -9149,7 +9149,7 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata, struct ieee80211_bss *bss = (void *)cbss->priv; struct sta_info *new_sta = NULL; struct ieee80211_link_data *link; - bool have_sta = false; + struct sta_info *have_sta = NULL; bool mlo; int err; u16 new_links; @@ -9168,11 +9168,8 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata, mlo = false; } - if (assoc) { - rcu_read_lock(); + if (assoc) have_sta = sta_info_get(sdata, ap_mld_addr); - rcu_read_unlock(); - } if (mlo && !have_sta && WARN_ON(sdata->vif.valid_links || sdata->vif.active_links)) @@ -9336,6 +9333,8 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata, out_release_chan: ieee80211_link_release_channel(link); out_err: + if (mlo && have_sta) + WARN_ON(__sta_info_destroy(have_sta)); ieee80211_vif_set_links(sdata, 0, 0); return err; }