Issue with overwriting .sig and resigning .efi

[bandie]

Issue with overwriting .sig and resigning .efi

[Bandie]

Hey,

1. Which script are you talking about?
2. I have barely experience in having EFI. If you say that this script should exclude them, we could do that.

[StarryTony]

Hi, 1. It’s the grub-sign scripts which sign all files in esp. But it also signs *.sig generated by itself and leads overwriting. 2. As .EFI have signatures signed by Microsoft to enable secure boot, resign could make their signatures be invalid. Thank you. On 2 Feb 2021, at 12:38, Bandie <[email protected]> wrote:  Hey, 1. Which script are you talking about? 2. I have barely experience in having EFI. If you say that this script should exclude them, we could do that. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#10 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ACINJO27TPXELNVIB5J3BTTS47W5ZANCNFSM4W6O5U6A>.

[Bandie]

To 1.: This sounds like it couldn't delete the old signatures before creating the new ones.. Do you run it as root?
To 2.: I'll look into that then.

[StarryTony]

To 1.: Sure, I run as root. It prompts me to overwrite each .sig file (Y/N). No existing .sig file before running the script. I can see all existing .sig files are generated by the script. So they are not old? Thank you. On 2 Feb 2021, at 12:55, Bandie <[email protected]> wrote:  To 1.: This sounds like it couldn't delete the old signatures before creating the new ones.. Do you run it as root? To 2.: I'll look into that then. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#10 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ACINJOYLA6HJO57AMEFB5N3S47Y45ANCNFSM4W6O5U6A>.

[Bandie]

hmh.. can you tell me which signature files exactly it tries to overwrite?

[StarryTony]

Hi, the script generates signatures for all files in esp. Therefore, it overwrites all .sig. For example, it generates a vmlinuz-linux.sig for vmlinuz-linux and then overwrites itself. On 2 Feb 2021, at 13:10, Bandie <[email protected]> wrote:  hmh.. can you tell me which signature files exactly it tries to overwrite? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#10 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ACINJOZBZ2VHO34ZHFL57NDS472SZANCNFSM4W6O5U6A>.

[Bandie]

Right now grub-sign signs every file in /boot. This is a script you use only once per grub-install.
If you do kernel upgrades, one should run grub-update-kernel-signature as it removes /boot/*.sig and resigns it.

[StarryTony]

Hi, Understand. But EFI are validated by shim as secure boot used. The validation chain looks like this: shim -> EFI -> Grub -> other grub files. I guess no need to re-sign EFI and Grub themselves. And most importantly, by removing an .efi file’s signature will prevent the computer boot from secure boot mode. Because EFI signatures have to be validated by UEFI boot loader. The issue is that grub-sign signs everything without excluding EFI. But it’s a must to keep EFI’s signatures to be validated by shim. On 6 Feb 2021, at 22:15, Bandie <[email protected]> wrote:  Right now grub-sign signs every file in /boot. This is a script you use only once per grub-install. If you do kernel upgrades, one should run grub-update-kernel-signature as it removes /boot/*.sig and resigns it. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#10 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ACINJO7UZNCKNNA7BQPFWR3S5W5PXANCNFSM4W6O5U6A>.