lkml.org 
[lkml]   [2018]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.18 177/235] gpiolib: dont allow userspace to set values of input lines
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bartosz Golaszewski <brgl@bgdev.pl>

[ Upstream commit e5332d5437764f775cf4e3b8ca3bf592af063a02 ]

User space can currently both read and set values of input lines using
the character device. This was not allowed by the old sysfs interface
nor is it a correct behavior.

Check the first descriptor in the set for the OUT flag when asked to
set values and return -EPERM if the line is input.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpio/gpiolib.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -449,7 +449,13 @@ static long linehandle_ioctl(struct file

return 0;
} else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
- /* TODO: check if descriptors are really output */
+ /*
+ * All line descriptors were created at once with the same
+ * flags so just check if the first one is really output.
+ */
+ if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
+ return -EPERM;
+
if (copy_from_user(&ghd, ip, sizeof(ghd)))
return -EFAULT;


\
 
 \ /
  Last update: 2018-09-24 14:49    [W:0.940 / U:2.784 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site