From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754886AbbBSAwX (ORCPT ); Wed, 18 Feb 2015 19:52:23 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:35574 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753876AbbBSAeT (ORCPT ); Wed, 18 Feb 2015 19:34:19 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Johan Hovold , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 058/103] USB: console: fix potential use after free Date: Wed, 18 Feb 2015 16:32:25 -0800 Message-Id: <1424305990-17983-59-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1424305990-17983-1-git-send-email-kamal@canonical.com> References: <1424305990-17983-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt16 -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: Kamal Mostafa --- 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 3cf2de4..e4ce48c 100644 --- a/drivers/usb/serial/console.c +++ b/drivers/usb/serial/console.c @@ -47,6 +47,8 @@ static struct console usbcons; * ------------------------------------------------------------ */ +static const struct tty_operations usb_console_fake_tty_ops = { +}; /* * The parsing of the command line works exactly like the @@ -139,15 +141,18 @@ 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; dev_err(&port->dev, "no more memory\n"); - goto free_tty; + goto put_tty; } + tty_port_tty_set(&port->port, tty); } /* only call the device specific open if this @@ -165,7 +170,7 @@ 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); } @@ -181,8 +186,8 @@ 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); -- 1.9.1