From patchwork Fri Oct 8 09:25:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathias Nyman X-Patchwork-Id: 12544711 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B7B2C433EF for ; Fri, 8 Oct 2021 09:23:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71CBD60FDC for ; Fri, 8 Oct 2021 09:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237822AbhJHJZP (ORCPT ); Fri, 8 Oct 2021 05:25:15 -0400 Received: from mga01.intel.com ([192.55.52.88]:41430 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237621AbhJHJZO (ORCPT ); Fri, 8 Oct 2021 05:25:14 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10130"; a="249830689" X-IronPort-AV: E=Sophos;i="5.85,357,1624345200"; d="scan'208";a="249830689" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Oct 2021 02:23:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.85,357,1624345200"; d="scan'208";a="489390518" Received: from mattu-haswell.fi.intel.com ([10.237.72.170]) by orsmga008.jf.intel.com with ESMTP; 08 Oct 2021 02:23:17 -0700 From: Mathias Nyman To: Cc: , Johan Hovold , stable@vger.kernel.org, Lu Baolu , Mathias Nyman Subject: [PATCH 3/5] USB: xhci: dbc: fix tty registration race Date: Fri, 8 Oct 2021 12:25:45 +0300 Message-Id: <20211008092547.3996295-4-mathias.nyman@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211008092547.3996295-1-mathias.nyman@linux.intel.com> References: <20211008092547.3996295-1-mathias.nyman@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Johan Hovold Make sure to allocate resources before registering the tty device to avoid having a racing open() and write() fail to enable rx or dereference a NULL pointer when accessing the uninitialised fifo. Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver") Cc: stable@vger.kernel.org # 4.16 Cc: Lu Baolu Signed-off-by: Johan Hovold Signed-off-by: Mathias Nyman --- drivers/usb/host/xhci-dbgtty.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c index 6e784f2fc26d..eb46e642e87a 100644 --- a/drivers/usb/host/xhci-dbgtty.c +++ b/drivers/usb/host/xhci-dbgtty.c @@ -408,40 +408,38 @@ static int xhci_dbc_tty_register_device(struct xhci_dbc *dbc) return -EBUSY; xhci_dbc_tty_init_port(dbc, port); - tty_dev = tty_port_register_device(&port->port, - dbc_tty_driver, 0, NULL); - if (IS_ERR(tty_dev)) { - ret = PTR_ERR(tty_dev); - goto register_fail; - } ret = kfifo_alloc(&port->write_fifo, DBC_WRITE_BUF_SIZE, GFP_KERNEL); if (ret) - goto buf_alloc_fail; + goto err_exit_port; ret = xhci_dbc_alloc_requests(dbc, BULK_IN, &port->read_pool, dbc_read_complete); if (ret) - goto request_fail; + goto err_free_fifo; ret = xhci_dbc_alloc_requests(dbc, BULK_OUT, &port->write_pool, dbc_write_complete); if (ret) - goto request_fail; + goto err_free_requests; + + tty_dev = tty_port_register_device(&port->port, + dbc_tty_driver, 0, NULL); + if (IS_ERR(tty_dev)) { + ret = PTR_ERR(tty_dev); + goto err_free_requests; + } port->registered = true; return 0; -request_fail: +err_free_requests: xhci_dbc_free_requests(&port->read_pool); xhci_dbc_free_requests(&port->write_pool); +err_free_fifo: kfifo_free(&port->write_fifo); - -buf_alloc_fail: - tty_unregister_device(dbc_tty_driver, 0); - -register_fail: +err_exit_port: xhci_dbc_tty_exit_port(port); dev_err(dbc->dev, "can't register tty port, err %d\n", ret);