Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933681AbcKILgO (ORCPT ); Wed, 9 Nov 2016 06:36:14 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:53892 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932981AbcKILFM (ORCPT ); Wed, 9 Nov 2016 06:05:12 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Linus Walleij Subject: [PATCH 4.8 015/138] gpio: GPIO_GET_LINEEVENT_IOCTL: Reject invalid line and event flags Date: Wed, 9 Nov 2016 11:44:58 +0100 Message-Id: <20161109102845.476286321@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161109102844.808685475@linuxfoundation.org> References: <20161109102844.808685475@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1997 Lines: 60 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lars-Peter Clausen commit ac7dbb991ee5afc0beacce3a252dcaaa249a7786 upstream. The GPIO_GET_LINEEVENT_IOCTL currently ignores unknown or undefined linehandle and lineevent flags. From a backwards and forwards compatibility viewpoint it is highly desirable to reject unknown flags though. On one hand an application that is using newer flags and is running on an older kernel has no way to detect if the new flags were handled correctly if they are silently discarded. On the other hand an application that (accidentally) passes undefined flags will run fine on an older kernel, but may break on a newer kernel when these flags get defined. Ensure that requests that have undefined flags set are rejected with an error, rather than silently discarding the undefined flags. Fixes: 61f922db7221 ("gpio: userspace ABI for reading GPIO line events") Signed-off-by: Lars-Peter Clausen Signed-off-by: Linus Walleij Signed-off-by: Greg Kroah-Hartman --- drivers/gpio/gpiolib.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -554,6 +554,10 @@ struct lineevent_state { struct mutex read_lock; }; +#define GPIOEVENT_REQUEST_VALID_FLAGS \ + (GPIOEVENT_REQUEST_RISING_EDGE | \ + GPIOEVENT_REQUEST_FALLING_EDGE) + static unsigned int lineevent_poll(struct file *filep, struct poll_table_struct *wait) { @@ -748,6 +752,13 @@ static int lineevent_create(struct gpio_ ret = -EINVAL; goto out_free_label; } + + /* Return an error if a unknown flag is set */ + if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || + (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) { + ret = -EINVAL; + goto out_free_label; + } /* This is just wrong: we don't look for events on output lines */ if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {