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Input: evdev - limit amount of data for writes

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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 <jeff@labundy.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Link: https://lore.kernel.org/r/Zr5L8TUzkJcB9HcF@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov 2024-08-15 11:41:53 -07:00
parent 6c65914a40
commit 6994d8b84b
1 changed files with 7 additions and 0 deletions
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7
drivers/input/evdev.c
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@ -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;