Verification-done on cosmic with grub2 / grub2-signed. Forcing an unsigned copy of the kernel, or one signed by an unknown key leads to the system failing to upgrade, as expected:
ubuntu@ubuntu:~$ dpkg -l grub-efi\* | grep ii | awk '{ print $2" "$3 }' grub-efi-amd64 2.02+dfsg1-5ubuntu8.1 grub-efi-amd64-bin 2.02+dfsg1-5ubuntu8.1 grub-efi-amd64-signed 1.110.1+2.02+dfsg1-5ubuntu8.1 ubuntu@ubuntu:~$ sudo apt install --reinstall grub-efi-amd64-signed Reading package lists... Done Building dependency tree Reading state information... Done 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded. Need to get 295 kB of archives. After this operation, 0 B of additional disk space will be used. Get:1 http://us.archive.ubuntu.com/ubuntu cosmic-proposed/main amd64 grub-efi-amd64-signed amd64 1.110.1+2.02+dfsg1-5ubuntu8.1 [295 kB] Fetched 295 kB in 0s (742 kB/s) (Reading database ... 106062 files and directories currently installed.) Preparing to unpack .../grub-efi-amd64-signed_1.110.1+2.02+dfsg1-5ubuntu8.1_amd64.deb ... Unpacking grub-efi-amd64-signed (1.110.1+2.02+dfsg1-5ubuntu8.1) over (1.110.1+2.02+dfsg1-5ubuntu8.1) ... Setting up grub-efi-amd64-signed (1.110.1+2.02+dfsg1-5ubuntu8.1) ... /boot/vmlinuz-4.18.0-14-matt is unsigned. E: Your kernels are not signed with a key known to your firmware. This system will fail to boot in a Secure Boot environment. dpkg: error processing package grub-efi-amd64-signed (--configure): installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1 Errors were encountered while processing: grub-efi-amd64-signed E: Sub-process /usr/bin/dpkg returned an error code (1) ubuntu@ubuntu:~$ ubuntu@ubuntu:~$ sudo sbsign --key ~/uefi-keys/uefi. uefi.crt uefi.key ubuntu@ubuntu:~$ sudo sbsign --key ~/uefi-keys/uefi.key --cert ~/uefi-keys/uefi.crt /boot/vmlinuz-4.18.0-14-matt ubuntu@ubuntu:~$ sudo apt install grub-efi-amd64-signed Reading package lists... Done Building dependency tree Reading state information... Done grub-efi-amd64-signed is already the newest version (1.110.1+2.02+dfsg1-5ubuntu8.1). 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Setting up grub-efi-amd64-signed (1.110.1+2.02+dfsg1-5ubuntu8.1) ... /boot/vmlinuz-4.18.0-14-matt.signed is signed, but using an unknown key: Subject: CN = PPA cyphermox efi /boot/vmlinuz-4.18.0-14-matt is unsigned. E: Your kernels are not signed with a key known to your firmware. This system will fail to boot in a Secure Boot environment. dpkg: error processing package grub-efi-amd64-signed (--configure): installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1 Errors were encountered while processing: grub-efi-amd64-signed E: Sub-process /usr/bin/dpkg returned an error code (1) ** Tags removed: verification-needed verification-needed-cosmic ** Tags added: verification-done-cosmic -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1789918 Title: grub2 signed kernel enforcement doesn't check on upgrade that signatures are from trusted keys To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1789918/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs