From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758797AbbA0MZJ (ORCPT ); Tue, 27 Jan 2015 07:25:09 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:35412 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932549AbbA0MTy (ORCPT ); Tue, 27 Jan 2015 07:19:54 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Johan Hovold , Luis Henriques Subject: [PATCH 3.16.y-ckt 108/126] USB: console: fix potential use after free Date: Tue, 27 Jan 2015 12:16:53 +0000 Message-Id: <1422361031-19364-109-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1422361031-19364-1-git-send-email-luis.henriques@canonical.com> References: <1422361031-19364-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 32a4bf2e81ec378e5925d4e069e0677a6c86a6ad upstream. Use tty kref to release the fake tty in usb_console_setup to avoid use after free if the underlying serial driver has acquired a reference. Note that using the tty destructor release_one_tty requires some more state to be initialised. Fixes: 4a90f09b20f4 ("tty: usb-serial krefs") Signed-off-by: Johan Hovold Signed-off-by: Luis Henriques --- drivers/usb/serial/console.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c index e56f394b58d8..29fa1c3d0089 100644 --- a/drivers/usb/serial/console.c +++ b/drivers/usb/serial/console.c @@ -46,6 +46,8 @@ static struct console usbcons; * ------------------------------------------------------------ */ +static const struct tty_operations usb_console_fake_tty_ops = { +}; /* * The parsing of the command line works exactly like the @@ -137,14 +139,17 @@ static int usb_console_setup(struct console *co, char *options) goto reset_open_count; } kref_init(&tty->kref); - tty_port_tty_set(&port->port, tty); tty->driver = usb_serial_tty_driver; tty->index = co->index; init_ldsem(&tty->ldisc_sem); + INIT_LIST_HEAD(&tty->tty_files); + kref_get(&tty->driver->kref); + tty->ops = &usb_console_fake_tty_ops; if (tty_init_termios(tty)) { retval = -ENOMEM; - goto free_tty; + goto put_tty; } + tty_port_tty_set(&port->port, tty); } /* only call the device specific open if this @@ -162,7 +167,7 @@ static int usb_console_setup(struct console *co, char *options) serial->type->set_termios(tty, port, &dummy); tty_port_tty_set(&port->port, NULL); - kfree(tty); + tty_kref_put(tty); } set_bit(ASYNCB_INITIALIZED, &port->port.flags); } @@ -178,8 +183,8 @@ static int usb_console_setup(struct console *co, char *options) fail: tty_port_tty_set(&port->port, NULL); - free_tty: - kfree(tty); + put_tty: + tty_kref_put(tty); reset_open_count: port->port.count = 0; usb_autopm_put_interface(serial->interface); -- 2.1.4