Commit 6994d8b8 authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: evdev - limit amount of data for writes 



Limit amount of data that can be written into an evdev instance at
a given time to 4096 bytes (170 input events) to avoid holding
evdev->mutex for too long and starving other users.

Reviewed-by: default avatarJeff LaBundy <jeff@labundy.com>
Reviewed-by: default avatarPeter Hutterer <peter.hutterer@who-t.net>
Link: https://lore.kernel.org/r/Zr5L8TUzkJcB9HcF@google.com


Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 6c65914a

drivers/input/evdev.c

+7 −0
Original line number Diff line number Diff line
@@ -498,6 +498,13 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer, 
	struct input_event event;

	int retval = 0;



	/*

	 * Limit amount of data we inject into the input subsystem so that

	 * we do not hold evdev->mutex for too long. 4096 bytes corresponds

	 * to 170 input events.

	 */

	count = min(count, 4096);



	if (count != 0 && count < input_event_size())

		return -EINVAL;