Patch "gpio: GPIO_GET_LINEEVENT_IOCTL: Reject invalid line and event flags" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

gpio: GPIO_GET_LINEEVENT_IOCTL: Reject invalid line and event flags

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
gpio-gpio_get_lineevent_ioctl-reject-invalid-line-and-event-flags.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Lars-Peter Clausen <[email protected]>
Date: Tue, 18 Oct 2016 16:54:06 +0200
Subject: gpio: GPIO_GET_LINEEVENT_IOCTL: Reject invalid line and event flags

From: Lars-Peter Clausen <[email protected]>

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.

---
 drivers/gpio/gpiolib.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

@@ -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) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/gpio-gpio_get_chipinfo_ioctl-fix-line-offset-validation.patch queue-4.8/gpio-gpio_get_line-handle-event-_ioctl-fix-file-descriptor-leak.patch queue-4.8/gpio-gpio_get_chipinfo_ioctl-fix-information-leak.patch queue-4.8/gpio-gpio_get_lineevent_ioctl-reject-invalid-line-and-event-flags.patch queue-4.8/gpio-gpiohandle_get_line_values_ioctl-fix-another-information-leak.patch queue-4.8/gpio-gpio_get_linehandle_ioctl-reject-invalid-line-flags.patch queue-4.8/gpio-gpio_get_lineevent_ioctl-validate-line-offset.patch queue-4.8/gpio-gpiohandle_get_line_values_ioctl-fix-information-leak.patch queue-4.8/gpio-gpio_get_linehandle_ioctl-validate-line-offset.patch