From cc45f313d85533d647ce619326302aad6f797c14 Mon Sep 17 00:00:00 2001 From: Zhao Li Date: Mon, 14 Sep 2026 23:28:25 +0800 Subject: [PATCH] wifi: cfg80211: preserve hidden-group beacon IE ownership A hidden-group probe-response entry borrows its beacon IEs from the group's beacon entry. cfg80211_update_assoc_bss_entry() can pass such an entry to cfg80211_update_known_bss() when merging scan entries after a channel switch. Copying the borrowed beacon_ies into the associated entry gives the same allocation two owners. Releasing the group's beacon entry can then leave the associated entry pointing to freed IEs, which are freed again when that entry is released. Skip beacon IE replacement when the source entry belongs to a hidden group. Preserve probe-response processing, the subsequent metadata updates, and the existing rejection path for conflicting hidden beacon updates. Fixes: 0afd425b1b64 ("cfg80211: fix duplicated scan entries after channel switch") Reported-by: Yilin Zhang Closes: https://lore.kernel.org/linux-wireless/20260901080427.1983015-1-yilinzhang@moonshot.ai/ Assisted-by: Codex:gpt-6-astra Signed-off-by: Zhao Li Signed-off-by: Johannes Berg --- net/wireless/scan.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index caa9c6495f20..d35c826c4b1a 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -1992,20 +1992,22 @@ cfg80211_update_known_bss(struct cfg80211_registered_device *rdev, return false; } - old = rcu_access_pointer(known->pub.beacon_ies); + if (!new->pub.hidden_beacon_bss) { + old = rcu_access_pointer(known->pub.beacon_ies); - rcu_assign_pointer(known->pub.beacon_ies, new->pub.beacon_ies); + rcu_assign_pointer(known->pub.beacon_ies, new->pub.beacon_ies); - /* Override IEs if they were from a beacon before */ - if (old == rcu_access_pointer(known->pub.ies)) - rcu_assign_pointer(known->pub.ies, new->pub.beacon_ies); + /* Override IEs if they were from a beacon before */ + if (old == rcu_access_pointer(known->pub.ies)) + rcu_assign_pointer(known->pub.ies, new->pub.beacon_ies); - cfg80211_update_hidden_bsses(known, - rcu_access_pointer(new->pub.beacon_ies), - old); + cfg80211_update_hidden_bsses(known, + rcu_access_pointer(new->pub.beacon_ies), + old); - if (old) - kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head); + if (old) + kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head); + } } known->pub.beacon_interval = new->pub.beacon_interval;