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 33352433045; Thu, 16 Jul 2026 14:28:06 +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=1784212090; cv=none; b=QCwrLk62vkPyB4VvhLTwalr9pOURNiIWvg1RgoVbjEqtMcpTi5nONIvf7jmUyo4ZZd69S6ir8LUIZz5DbVzzprQXfQY0q7i5eDoVFszoLW+/j9sXP2j0aOsn/eGMxVaSCPfsdTVkYFQ6buu44o0eYoYXCKXo1OrXMqRthMW8AMs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784212090; c=relaxed/simple; bh=gxZePhAwWpPoG5TstdY6EydsyMDTwy4PI0khKIhhqoo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eFc7H1EUtZRe3YDieLzxqBopP2bKeHJAx5WiZ/oNPUjCVE8gIr0Fw9KWFdzV+ICGZJMokcuEX5zPwJ6/Wf0IeQndNSdoByzLKE5CoIo3RLBcD+PLgwh5Ow8VMaWfWB7xnqAq6vhtllJCL68xczZzLQgDKOeNoexlujk2aVAlfKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jm/bs/Hu; 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="jm/bs/Hu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12A801F00A3A; Thu, 16 Jul 2026 14:28:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784212086; bh=rN8kBXupdd0bd/sHc+GcJZjmkoGu8RXqJuvrMtNEAv4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jm/bs/HuJy5L+T8okdkN0BEfyNODoeh5pns5m16A676StqqNEZvIRSEIp9vO9dvJG Ir4W3yV1ZY4Y+OImvRYqYhOdW26Xk+2GDDAk8G6nCIgSsOj5E+3d0NQFhjRSDcP/hS IddSn+7nMQc+9uEKKS7pTOj2/EhzIdmnMhaNSx/s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+fed5dce4553262f3b35c@syzkaller.appspotmail.com, Yousef Alhouseen , Luiz Augusto von Dentz Subject: [PATCH 6.12 151/349] Bluetooth: bnep: pin L2CAP connection during netdev registration Date: Thu, 16 Jul 2026 15:31:25 +0200 Message-ID: <20260716133036.763857705@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133033.287196923@linuxfoundation.org> References: <20260716133033.287196923@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yousef Alhouseen commit bb067a99a0356196c0b89a95721985485ebce5a5 upstream. bnep_add_connection() reads the L2CAP connection without holding the channel lock, then passes its HCI device to register_netdev(). Controller teardown can clear and release that connection concurrently, leaving the network device registration path to dereference a freed parent device. Take a reference to the L2CAP connection while holding the channel lock. Retain it until register_netdev() has taken the parent device reference. Fixes: 65f53e9802db ("Bluetooth: Access BNEP session addresses through L2CAP channel") Reported-by: syzbot+fed5dce4553262f3b35c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=fed5dce4553262f3b35c Cc: stable@vger.kernel.org Signed-off-by: Yousef Alhouseen Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/bnep/core.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) --- a/net/bluetooth/bnep/core.c +++ b/net/bluetooth/bnep/core.c @@ -562,14 +562,18 @@ static int bnep_session(void *arg) return 0; } -static struct device *bnep_get_device(struct bnep_session *session) +static struct l2cap_conn *bnep_get_conn(struct bnep_session *session) { - struct l2cap_conn *conn = l2cap_pi(session->sock->sk)->chan->conn; + struct l2cap_chan *chan = l2cap_pi(session->sock->sk)->chan; + struct l2cap_conn *conn; - if (!conn || !conn->hcon) - return NULL; + l2cap_chan_lock(chan); + conn = chan->conn; + if (conn) + l2cap_conn_get(conn); + l2cap_chan_unlock(chan); - return &conn->hcon->dev; + return conn; } static const struct device_type bnep_type = { @@ -581,6 +585,7 @@ int bnep_add_connection(struct bnep_conn u32 valid_flags = BIT(BNEP_SETUP_RESPONSE); struct net_device *dev; struct bnep_session *s, *ss; + struct l2cap_conn *conn = NULL; u8 dst[ETH_ALEN], src[ETH_ALEN]; int err; @@ -640,10 +645,18 @@ int bnep_add_connection(struct bnep_conn bnep_set_default_proto_filter(s); #endif - SET_NETDEV_DEV(dev, bnep_get_device(s)); + conn = bnep_get_conn(s); + if (!conn) { + err = -ENOTCONN; + goto failed; + } + + SET_NETDEV_DEV(dev, &conn->hcon->dev); SET_NETDEV_DEVTYPE(dev, &bnep_type); err = register_netdev(dev); + l2cap_conn_put(conn); + conn = NULL; if (err) goto failed; @@ -665,6 +678,8 @@ int bnep_add_connection(struct bnep_conn return 0; failed: + if (conn) + l2cap_conn_put(conn); up_write(&bnep_session_sem); free_netdev(dev); return err;