[PATCH 5.2 25/85] gpio: fix line flag validation in lineevent_create

Greg Kroah-Hartman
2019-09-18T06:25:06Z

From: Kent Gibson <warthog618@gmail.com>

commit 5ca2f54b597c816df54ff1b28eb99cf7262b955d upstream.

lineevent_create should not allow any of GPIOHANDLE_REQUEST_OUTPUT,
GPIOHANDLE_REQUEST_OPEN_DRAIN or GPIOHANDLE_REQUEST_OPEN_SOURCE to be set.

Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpio/gpiolib.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -934,7 +934,9 @@ static int lineevent_create(struct gpio_
}

/* This is just wrong: we don't look for events on output lines */
- if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
+ if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
+ (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+ (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) {
ret = -EINVAL;
goto out_free_label;
}
@@ -948,10 +950,6 @@ static int lineevent_create(struct gpio_

if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
set_bit(FLAG_ACTIVE_LOW, &desc->flags);
- if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN)
- set_bit(FLAG_OPEN_DRAIN, &desc->flags);
- if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
- set_bit(FLAG_OPEN_SOURCE, &desc->flags);

ret = gpiod_direction_input(desc);
if (ret)