From 6310aafd42674e162b9f996ddd76f6fe0d8bf321 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 24 Jun 2025 13:07:49 +0200 Subject: [PATCH] wifi: mac80211: finish link init before RCU publish [ Upstream commit d87c3ca0f8f1ca4c25f2ed819e954952f4d8d709 ] Since the link/conf pointers can be accessed without any protection other than RCU, make sure the data is actually set up before publishing the structures. Fixes: b2e8434f1829 ("wifi: mac80211: set up/tear down client vif links properly") Link: https://patch.msgid.link/20250624130749.9a308b713c74.I4a80f5eead112a38730939ea591d2e275c721256@changeid Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/link.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/net/mac80211/link.c b/net/mac80211/link.c index 16cbaea93fc3..af4d2b2e9a26 100644 --- a/net/mac80211/link.c +++ b/net/mac80211/link.c @@ -28,8 +28,16 @@ void ieee80211_link_init(struct ieee80211_sub_if_data *sdata, if (link_id < 0) link_id = 0; - rcu_assign_pointer(sdata->vif.link_conf[link_id], link_conf); - rcu_assign_pointer(sdata->link[link_id], link); + if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) { + struct ieee80211_sub_if_data *ap_bss; + struct ieee80211_bss_conf *ap_bss_conf; + + ap_bss = container_of(sdata->bss, + struct ieee80211_sub_if_data, u.ap); + ap_bss_conf = sdata_dereference(ap_bss->vif.link_conf[link_id], + ap_bss); + memcpy(link_conf, ap_bss_conf, sizeof(*link_conf)); + } link->sdata = sdata; link->link_id = link_id; @@ -65,6 +73,9 @@ void ieee80211_link_init(struct ieee80211_sub_if_data *sdata, ieee80211_link_debugfs_add(link); } + + rcu_assign_pointer(sdata->vif.link_conf[link_id], link_conf); + rcu_assign_pointer(sdata->link[link_id], link); } void ieee80211_link_stop(struct ieee80211_link_data *link)