Huh. I must be outdated. I didn’t know they got secure boot working. So what do you do when you need to update your kernel? Or does the fact that it comes from the package manager mean that it is allowed to update that?
Generally yes. For many distros, the kernel signing key is with the distro maintainers and so the package comes with pre-signed kernel images. For distros like Arch and Gentoo, it’s the user’s responsibility to maintain the signing key and sign each updated kernel
The firmware has to allow it, so if you’ve got physical access to the machine that’s possible. Remote access root, on the other hand, can’t tell the firmware to register new keys as long as it’s configured correctly
Huh. I must be outdated. I didn’t know they got secure boot working. So what do you do when you need to update your kernel? Or does the fact that it comes from the package manager mean that it is allowed to update that?
The package manager doesn’t have special permission. The new kernel you download is also signed for you and trusted by your system.
If it wasn’t trusted, would the next time you boot the kernel won’t load because the bootloader will refuse to load the unsigned code.
Generally yes. For many distros, the kernel signing key is with the distro maintainers and so the package comes with pre-signed kernel images. For distros like Arch and Gentoo, it’s the user’s responsibility to maintain the signing key and sign each updated kernel
So why can’t root add new keys?
The firmware has to allow it, so if you’ve got physical access to the machine that’s possible. Remote access root, on the other hand, can’t tell the firmware to register new keys as long as it’s configured correctly