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 3274432A3C9; Sun, 7 Jun 2026 10:28:26 +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=1780828109; cv=none; b=fz/aXiOaekilCU5Fi+uWwzqY1+4QEfpoFWvZ+354xfy5/tEqTN0KN2gRCBMF7CwmuQDpkN6IusvPFdsYiL27O6RAOxuDFSPx5UGEHotz7GlQPkZywSpIJv+9swQuqpyDZfXm16x8DcL9HP5h17V9Rdw3yXBPSCB6QfM2T+8r4WM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780828109; c=relaxed/simple; bh=X/LJ4ghTWOi2qVDxJCGe9Cv/XhyuAOFN3Zlgx0gON+E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FGsChNXJ0SXB0d3TrvfjiVhDCUoW4umsFiuTIQjQM/I9SJm9dJjbz0dfFGPY+8FQ6X2zzCKyEbkscqLJnUtc965KmvMCtLJjntIvxQvqrbAXlV2XsS9tZuN+QJ4jm3P85WEjFPiwJP6p+ibk8ON1MYqwZSd1Ss39pGmQu+zRxr0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hgt7OWO5; 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="hgt7OWO5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 261A31F00898; Sun, 7 Jun 2026 10:28:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780828105; bh=vdkRaFC8Uxh+nfzVJaFmNhnFuUiEhfreC5e8GuI86As=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hgt7OWO5W/SbZvivdjBsZ7LIcxaaU+yOcbds0BWoXySLioKb2yYgjE52DjYlM+c9w HRR2UXGFg98gwOo9szM7jIVkrKwJyhAyq05WpnZ12uApV6kKySRN5WAzLu9X3FuZ+Z oIxnq9R6H6VV/IuV4D88bGBJUpG166xc6FqLvdVw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Siwei Zhang , Luiz Augusto von Dentz Subject: [PATCH 6.18 128/315] Bluetooth: L2CAP: use chan timer to close channels in cleanup_listen() Date: Sun, 7 Jun 2026 11:58:35 +0200 Message-ID: <20260607095732.326093089@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260607095727.528828913@linuxfoundation.org> References: <20260607095727.528828913@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Siwei Zhang commit 8c8e620467a7b51562dbcefbd1f09f288d7d710d upstream. l2cap_chan_close() removes the channel from conn->chan_l, which must be done under conn->lock. cleanup_listen() runs under the parent sk_lock, so acquiring conn->lock would invert the established conn->lock -> chan->lock -> sk_lock order. Instead of calling l2cap_chan_close() directly, schedule l2cap_chan_timeout with delay 0 to close the channel asynchronously. The timeout handler already acquires conn->lock and chan->lock in the correct order. The timer is only armed when chan->conn is still set: if it is already NULL, l2cap_conn_del() has already processed this channel (l2cap_chan_del + l2cap_sock_teardown_cb + l2cap_sock_close_cb), so there is nothing left to do. If l2cap_conn_del() races in after the timer is armed, __clear_chan_timer() inside l2cap_chan_del() cancels it; if the timer has already fired, the handler returns harmlessly because chan->conn was cleared. Fixes: 3df91ea20e74 ("Bluetooth: Revert to mutexes from RCU list") Cc: # 0b58004: Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del() Signed-off-by: Siwei Zhang Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/l2cap_sock.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1481,6 +1481,10 @@ static void l2cap_sock_cleanup_listen(st * pin it (hold_unless_zero() additionally skips a chan already past * its last reference). We then drop the sk lock before taking * chan->lock, so sk and chan locks are never held together. + * + * Since we cannot call l2cap_chan_close() without conn->lock, + * schedule l2cap_chan_timeout to close the channel; it already + * acquires conn->lock -> chan->lock in the correct order. */ while ((sk = bt_accept_dequeue(parent, NULL))) { struct l2cap_chan *chan; @@ -1498,14 +1502,12 @@ static void l2cap_sock_cleanup_listen(st state_to_string(chan->state)); l2cap_chan_lock(chan); - __clear_chan_timer(chan); - l2cap_chan_close(chan, ECONNRESET); - /* l2cap_conn_del() may already have killed this socket - * (it sets SOCK_DEAD); skip the duplicate to avoid a - * double sock_put()/l2cap_chan_put(). + /* Since we cannot call l2cap_chan_close() without + * conn->lock, schedule its timer to trigger the close + * and cleanup of this channel. */ - if (!sock_flag(sk, SOCK_DEAD)) - l2cap_sock_kill(sk); + if (chan->conn) + __set_chan_timer(chan, 0); l2cap_chan_unlock(chan); l2cap_chan_put(chan);