Re: USB Denial Of Service
From: Oliver Neukum
Date: Wed Jun 12 2024 - 04:00:56 EST
On 11.06.24 16:35, Alan Stern wrote:
Greg, Oliver, or anyone else:
Questions:
If a broken or malicious device causes a USB class driver to add a
thousand (or more) error messages per second to the kernel log,
indefinitely, would that be considered a form of DOS?
Yes.
Should the driver be fixed?
If a broken device can do that, definitely.
What is an acceptable rate for an unending stream of error messages?
Once a second? Once a minute?
Definitely not once a second. I'd be tempted to call a neverending stream
an issue by itself. The approach the SCSI layer takes by giving up on
a device if all else fails seems wise to me.
At what point should the driver give up and stop trying to communicate
with the device?
I would propose after five cycles of all error handling.
The exact number, as long as it is greater than 1 and a small integer
does not really matter, as long as it exists.
Regards
Oliver