From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9FDD33B3BE1; Wed, 30 Sep 2026 18:11:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791920; cv=none; b=NZ2D/8G1Ea3kK2gCcXew74cH612K7q1Lnkp6qbqVuCNiu2KPk8BmDlvxQCC3Gtn6WGsTKQkA1FxRRBtWP58+bqv8ZW+l0m9qcKropC7S00i1hRfCIghGj1Q/iLmk3n2bHrRaE+gIW4Gtqn0Qia29aLHGdJBL4iRIWDL6QrsmRyc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791920; c=relaxed/simple; bh=mt5o9BcMkfrkrauM/Xcszwb4CDb62T9W2Se0rSxBLjs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gGstjUWlX0C3dj+2cXdQTbdOFcQGBlYFg62tDFbbalbQMs8w1+3GADvVDeWaTX5lfH1CCObq4Uf58u6LRBiHr19CfoOb8hIIKejxZC2ekcWG8tgXGyOG6Ol4n0b1XRbwCMLM4UlWkKuTGRMewKPmqGHSz+4WwGrF9gwa4EIYVjg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JtONx3ja; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="JtONx3ja" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 058E01F000FF; Wed, 30 Sep 2026 18:11:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791919; bh=9dXjyP03x9ONCOhHMdtM1EFjPw42xpRWLLc2i2HnloA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JtONx3ja45uiRvFGrl/jlZelNbdj3dihB0B27W7YehcHE6HzR/wrdiA5ZG8m5E67W 20NNuRbjqY+7WQ7lQCb9uMWsIDiVDtWOe3B1al9Utymm1CQine0PhKMquFq3OHH8mL iW4RTYGAWrvVnetWAyKOhyL4aSGcAXDn6lrXidA8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+1a797e1c81be78a2ace7@syzkaller.appspotmail.com, Johannes Berg , Sasha Levin Subject: [PATCH 5.15 473/752] wifi: cfg80211: only group hidden BSSes with beacon entries Date: Wed, 30 Sep 2026 17:25:43 +0200 Message-ID: <20260930152408.508549030@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Berg [ Upstream commit 068843ed0902c552a13860c5ec6b2ca65b57a065 ] When a probe response for an unknown BSS comes in, __cfg80211_bss_update() looks for an existing entry with the same BSSID and a hidden (zero-length or NUL-filled) SSID, and if it finds one it groups them, using the beacon IEs from the existing entry. But that could find another entry without a beacon, if it was also from a probe response (with SSID), so there's a group without beacon elements. If a beacon with a hidden SSID for that BSSID arrives later, cfg80211_combine_bsses() goes looking for the probe response entries that belong to it - i.e. entries with the same BSSID and channel that have no beacon IEs - and finds those two. They are already grouped with each other, so it hits its WARN_ON_ONCE(bss->pub.hidden_beacon_bss) WARN_ON_ONCE(!list_empty(&bss->hidden_list)) which are there because an entry without beacon elements is not supposed to be part of a group yet. Only combine entries when a beacon was already received, ones that are kept separate will be combined when a beacon arrives. Assisted-by: LLM Fixes: 4593c4cbe1c9 ("cfg80211: fix BSS list hidden SSID lookup") Reported-by: syzbot+1a797e1c81be78a2ace7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=1a797e1c81be78a2ace7 Link: https://patch.msgid.link/20260904165614.bcfa64715745.Iad740347c86de56d4ff4f96a95f3c3afc47c42de@changeid Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/wireless/scan.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index df9d0431864d3..de1e89f471a17 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -1862,6 +1862,13 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev, if (!hidden) hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_NUL); + /* + * Only group with an entry with beacon data, otherwise + * beacon data can never be filled/updated. + */ + if (hidden && + !rcu_access_pointer(hidden->pub.beacon_ies)) + hidden = NULL; if (hidden) { new->pub.hidden_beacon_bss = &hidden->pub; list_add(&new->hidden_list, -- 2.53.0