Commit 0f4bbb23 authored Oct 18, 2016 by Lars-Peter Clausen Committed by Linus Walleij Oct 21, 2016

gpio: GPIO_GET_CHIPINFO_IOCTL: Fix information leak



The GPIO_GET_CHIPINFO_IOCTL handler allocates a gpiochip_info struct on the
stack and then passes it to copy_to_user(). But depending on the length of
the GPIO chip name and label the struct is only partially initialized.

This exposes the previous, potentially sensitive, stack content to the
issuing userspace application. To avoid this make sure that the struct is
fully initialized.

Cc: stable@vger.kernel.org
Fixes: 521a2ad6 ("gpio: add userspace ABI for GPIO line information")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

parent 1f1cc456

drivers/gpio/gpiolib.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -823,6 +823,8 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
	if (cmd == GPIO_GET_CHIPINFO_IOCTL) {		if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
	struct gpiochip_info chipinfo;		struct gpiochip_info chipinfo;

			memset(&chipinfo, 0, sizeof(chipinfo));

	strncpy(chipinfo.name, dev_name(&gdev->dev),		strncpy(chipinfo.name, dev_name(&gdev->dev),
	sizeof(chipinfo.name));		sizeof(chipinfo.name));
	chipinfo.name[sizeof(chipinfo.name)-1] = '\0';		chipinfo.name[sizeof(chipinfo.name)-1] = '\0';