The creator of systemd (Lennart Poettering) has recently created a new company dedicated to bringing hardware attestation to open source software.
What might this entail? A previous blog post could provide some clues:
So, let’s see how I would build a desktop OS. The trust chain matters, from the boot loader all the way to the apps. This means all code that is run must be cryptographically validated before it is run. This is in fact where big distributions currently fail pretty badly. This is a fault of current Linux distributions though, not of SecureBoot in general.
If this technology is successful, the end result could be that we would see our Linux laptops one day being as locked down as an Iphone or Android device.
There are lots of others who are equally concerned about this possibility: https://news.ycombinator.com/item?id=46784572
Who decides what SecureBoot considers trustworthy? If SecureBoot is controlled by someone else then it can be used against the user. The aversion to SecureBoot is justified.
Secureboot uses certificates to verify integrity. The user is able to install new certificates. So I’d say it is the user? I’m not an expert though and their may be hardware out there that doesn’t allow new certificates.