[PATCH 3.12 001/101] Input: evdev - fix EVIOCG{type} ioctl

From: Jiri Slaby
Date: Wed Dec 03 2014 - 07:01:21 EST

From: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


commit 7c4f56070fde2367766fa1fb04852599b5e1ad35 upstream.

The 'max' size passed into the function is measured in number of bits
(KEY_MAX, LED_MAX, etc) so we need to convert it accordingly before trying
to copy the data out, otherwise we will try copying too much and end up
with up with a page fault.

Reported-by: Pavel Machek <pavel@xxxxxx>
Reviewed-by: Pavel Machek <pavel@xxxxxx>
Reviewed-by: David Herrmann <dh.herrmann@xxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
drivers/input/evdev.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index a06e12552886..694af4958a98 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -757,20 +757,23 @@ static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
static int evdev_handle_get_val(struct evdev_client *client,
struct input_dev *dev, unsigned int type,
- unsigned long *bits, unsigned int max,
- unsigned int size, void __user *p, int compat)
+ unsigned long *bits, unsigned int maxbit,
+ unsigned int maxlen, void __user *p,
+ int compat)
int ret;
unsigned long *mem;
+ size_t len;

- mem = kmalloc(sizeof(unsigned long) * max, GFP_KERNEL);
+ len = BITS_TO_LONGS(maxbit) * sizeof(unsigned long);
+ mem = kmalloc(len, GFP_KERNEL);
if (!mem)
return -ENOMEM;


- memcpy(mem, bits, sizeof(unsigned long) * max);
+ memcpy(mem, bits, len);


@@ -778,7 +781,7 @@ static int evdev_handle_get_val(struct evdev_client *client,


- ret = bits_to_user(mem, max, size, p, compat);
+ ret = bits_to_user(mem, maxbit, maxlen, p, compat);
if (ret < 0)


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