From 26e84445f02ce6b2fe5f3e0e28ff7add77f35e08 Mon Sep 17 00:00:00 2001 From: Dmitry Antipov Date: Wed, 13 Aug 2025 16:52:36 +0300 Subject: [PATCH] wifi: cfg80211: fix use-after-free in cmp_bss() Following bss_free() quirk introduced in commit 776b3580178f ("cfg80211: track hidden SSID networks properly"), adjust cfg80211_update_known_bss() to free the last beacon frame elements only if they're not shared via the corresponding 'hidden_beacon_bss' pointer. Reported-by: syzbot+30754ca335e6fb7e3092@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=30754ca335e6fb7e3092 Fixes: 3ab8227d3e7d ("cfg80211: refactor cfg80211_bss_update") Signed-off-by: Dmitry Antipov Link: https://patch.msgid.link/20250813135236.799384-1-dmantipov@yandex.ru Signed-off-by: Johannes Berg --- net/wireless/scan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index a8339ed52404c..6c7b7c3828a41 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -1916,7 +1916,8 @@ cfg80211_update_known_bss(struct cfg80211_registered_device *rdev, */ f = rcu_access_pointer(new->pub.beacon_ies); - kfree_rcu((struct cfg80211_bss_ies *)f, rcu_head); + if (!new->pub.hidden_beacon_bss) + kfree_rcu((struct cfg80211_bss_ies *)f, rcu_head); return false; } -- 2.39.5