[patch] gpiolib: shifters used as flags in gpio_ioctl()

[patch] gpiolib: shifters used as flags in gpio_ioctl()

[Dan Carpenter]

We weren't testing whether the bits were set correctly because we used
shifters as flags.  It means that we give the user incorrect line
information in this new ioctl.

Fixes: 521a2ad6f862 ('gpio: add userspace ABI for GPIO line information')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index b816469..d609e03 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -380,17 +380,19 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		 * this GPIO so it can't use it.
 		 */
 		lineinfo.flags = 0;
-		if (desc->flags & (FLAG_REQUESTED | FLAG_IS_HOGGED |
-				   FLAG_USED_AS_IRQ | FLAG_EXPORT |
-				   FLAG_SYSFS))
+		if (desc->flags & ((1 << FLAG_REQUESTED) |
+				   (1 << FLAG_IS_HOGGED) |
+				   (1 << FLAG_USED_AS_IRQ) |
+				   (1 << FLAG_EXPORT) |
+				   (1 << FLAG_SYSFS)))
 			lineinfo.flags |= GPIOLINE_FLAG_KERNEL;
-		if (desc->flags & FLAG_IS_OUT)
+		if (test_bit(FLAG_IS_OUT, &desc->flags))
 			lineinfo.flags |= GPIOLINE_FLAG_IS_OUT;
-		if (desc->flags & FLAG_ACTIVE_LOW)
+		if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
 			lineinfo.flags |= GPIOLINE_FLAG_ACTIVE_LOW;
-		if (desc->flags & FLAG_OPEN_DRAIN)
+		if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
 			lineinfo.flags |= GPIOLINE_FLAG_OPEN_DRAIN;
-		if (desc->flags & FLAG_OPEN_SOURCE)
+		if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
 			lineinfo.flags |= GPIOLINE_FLAG_OPEN_SOURCE;
 
 		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))

Re: [patch] gpiolib: shifters used as flags in gpio_ioctl()

[Linus Walleij]

On Tue, Feb 23, 2016 at 10:44 AM, Dan Carpenter
<dan.carpenter@oracle.com> wrote:

> We weren't testing whether the bits were set correctly because we used
> shifters as flags.  It means that we give the user incorrect line
> information in this new ioctl.
>
> Fixes: 521a2ad6f862 ('gpio: add userspace ABI for GPIO line information')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Already wrote and queued a similar patch yesterday, but thanks anyway Dan!

Yours,
Linus Walleij