Commit 8a122b5e authored by Dan Carpenter's avatar Dan Carpenter Committed by Bartosz Golaszewski
Browse files

gpio: virtuser: Fix uninitialized data bug in gpio_virtuser_direction_do_write() 



If *ppos is non-zero (user-space write split over multiple calls to
write()) then simple_write_to_buffer() won't initialize the start of the
buffer. Really, non-zero values for *ppos aren't going to work at all.
Check for that and return -EINVAL at the start of the function.

Fixes: 91581c4b ("gpio: virtuser: new virtual testing driver for the GPIO API")
Signed-off-by: default avatarDan Carpenter <error27@gmail.com>
Link: https://patch.msgid.link/ahP3BJWWy-m_qI0X@stanley.mountain


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
parent 9d7697fa

drivers/gpio/gpio-virtuser.c

+2 −2
Original line number Diff line number Diff line
@@ -397,7 +397,7 @@ static ssize_t gpio_virtuser_direction_do_write(struct file *file, 
	char buf[32], *trimmed;

	int ret, dir, val = 0;



	if (count >= sizeof(buf))

	if (*ppos != 0 || count >= sizeof(buf))

		return -EINVAL;



	ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, user_buf, count);
@@ -622,7 +622,7 @@ static ssize_t gpio_virtuser_consumer_write(struct file *file, 
	char buf[GPIO_VIRTUSER_NAME_BUF_LEN + 2];

	int ret;



	if (count >= sizeof(buf))

	if (*ppos != 0 || count >= sizeof(buf))

		return -EINVAL;



	ret = simple_write_to_buffer(buf, GPIO_VIRTUSER_NAME_BUF_LEN, ppos,