shim VS sbctl

Microsoft doesn't really sign other people's code for UEFI. They do sign shim (https://github.com/rhboot/shim) which will look at other keys the user registered with UEFI to load other components to enable you to write custom third party UEFI modules while still supporting secure boot.

In this case, the distros first boot loader is shim, which is signed by Microsoft. Shim is FOSS: https://github.com/rhboot/shim

How do I get dual boot set up and running? There doesn't seem so much documentation about this sbat chicanery as it was introduced to shim in 2021 and patched in rEFInd a bit more than a month ago, so I suppose not enough people have had this trouble yet.

Secure boot still isn't "secure" at all because microsoft has signed multiple bootloaders with their own keys, which exist only to chain load a second bootloader. See https://github.com/rhboot/shim and https://blog.hansenpartnership.com/linux-foundation-secure-boot-system-released/

A new mechanism called SBAT (https://github.com/rhboot/shim/blob/main/SBAT.md) is now used to allow revocation of groups of bootloaders rather than individual hashes in order to mitigate the resource consumption

{ echo "sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md" echo "systemd-boot,1,systemd,systemd-boot,1,https://systemd.io" } > sbat.csv

Yeah, that incident instigated a totally new approach to revoking bad bootloaders that everybody (including Microsoft) should be using nowadays. So I guess HP just never got the memo.

No, this isn't true nor correct.

Secure Boot and TPM do offer tangible security benefits and is security features you can take ownership of.

Secure Boot allows your own key hierarchy, and TPM allows you to take ownership.

The linked boot disk isn't really proof that Secure Boot is useless. If you don't set a MOKManager password (as you should), and you change the security state of the machine while present at the keyboard. Yes you can boot things.

This is intended to make sure people can actually decide to trust things. And having insecure defaults makes this less useful. Not very surprising.

TPMs could also prevent attacks like this on your machine.

Incidentally I've invested quite a bit of time in making user-friendly Secure Boot tooling as well. https://github.com/Foxboron/sbctl

No problem! The sbctl package ships with a pretty extensive hook out of the box (https://github.com/Foxboron/sbctl/blob/master/contrib/pacman/ZZ-sbctl.hook). It's been very reliable for automatically resigning .efi executables after updates for me.

sbctl verify returns failed to find EFI system partition despite it definitely is there. It's the same issue as this but remounting or restarting doesn't fix it.

lol

Must actually prevent unsigned images from booting

sudo dnf install asciidoc golang -y VERSION=0.11 cd /tmp curl -L "https://github.com/Foxboron/sbctl/releases/download/${VERSION}/sbctl-${VERSION}.tar.gz" | tar zxvf - cd "sbctl-${VERSION}" make sudo make install cd ~

By far the easiest is to use sbctl to generate, install and use keys to sign your efi images. You can use mkinitcpio to build the unified kernels automatically and a pacman trigger to rerun the sbctl signing when the kernel is updated. Pretty straightforward (once you've done it once).

The question is whether you have any UEFI drivers or not. If they're in the ESP you can just look there to check, but UEFI drivers can also be loaded from PCI cards or baked in the firmware itself.

If you're using a TPM for Secure Boot, you can use the command in https://github.com/Foxboron/sbctl/wiki/FAQ#option-rom to know for sure.