[PATCH wireless-next 03/15] wifi: mac80211: verify state before connection

[Miri Korenblit <miriam.rachel.korenblit@xxxxxxxxx>]

ieee80211_prep_connection is supposed to be called when both bitmaps
(valid_links and active_links) are cleared.
Make sure of it and WARN if this is not the case, to avoid weird issues.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@xxxxxxxxx>
Reviewed-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
 net/mac80211/mlme.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index d8953a855ab4..c8bf810ff5d8 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -8694,21 +8694,33 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata,
 	bool have_sta = false;
 	bool mlo;
 	int err;
+	u16 new_links;
 
 	if (link_id >= 0) {
 		mlo = true;
 		if (WARN_ON(!ap_mld_addr))
 			return -EINVAL;
-		err = ieee80211_vif_set_links(sdata, BIT(link_id), 0);
+		new_links = BIT(link_id);
 	} else {
 		if (WARN_ON(ap_mld_addr))
 			return -EINVAL;
 		ap_mld_addr = cbss->bssid;
-		err = ieee80211_vif_set_links(sdata, 0, 0);
+		new_links = 0;
 		link_id = 0;
 		mlo = false;
 	}
 
+	if (assoc) {
+		rcu_read_lock();
+		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))
+		return -EINVAL;
+
+	err = ieee80211_vif_set_links(sdata, new_links, 0);
 	if (err)
 		return err;
 
@@ -8729,12 +8741,6 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata,
 		goto out_err;
 	}
 
-	if (assoc) {
-		rcu_read_lock();
-		have_sta = sta_info_get(sdata, ap_mld_addr);
-		rcu_read_unlock();
-	}
-
 	if (!have_sta) {
 		if (mlo)
 			new_sta = sta_info_alloc_with_link(sdata, ap_mld_addr,
-- 
2.34.1