From: Dmitry Torokhov Date: Thu, 15 Aug 2024 18:41:53 +0000 (-0700) Subject: Input: evdev - limit amount of data for writes X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=6994d8b84bfd71431bfccb5baf84a827086d48a5;p=users%2Fjedix%2Flinux-maple.git 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: Jeff LaBundy Reviewed-by: Peter Hutterer Link: https://lore.kernel.org/r/Zr5L8TUzkJcB9HcF@google.com Signed-off-by: Dmitry Torokhov --- diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index a8ce3d140722..eb4906552ac8 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -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;