Ubuntu
shim package

shim's fallback hangs in CopyMem, can't boot ISOs

Bug #1959618 reported by valdikss
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
shim (Ubuntu)
Triaged
Low
Unassigned

Bug Description

I'm getting black screen trying to boot KDE Neon Unstable neon-unstable-20220130-0332.iso, which uses
shim-signed 1.40.7+15.4-0ubuntu9

This is due to a bug in shim 15.4 fallback (fbx64.efi), it fails on CopyMem inside add_to_boot_list on my Lenovo X220 in this place of fallback.c:

    CopyMem(newbootorder + 1, bootorder, sizeof (CHAR16) * option);
    CopyMem(newbootorder + option + 1, bootorder + option + 1,
        sizeof (CHAR16) * (nbootorder - option - 1));

The fix already present in upstream:
https://github.com/rhboot/shim/commit/41319e14c9144063605750baccd5bb332a3cf4fc

Kindly asking to apply this patch or update shim to current git master.

Revision history for this message
Steve Langasek (vorlon) wrote :

This appears to be a valid bug report against shim based on the described problematic behavior of the upstream binary. However, fbx64.efi should not be included on ISO images; there is also a bug in the mastering of this (non-Ubuntu) ISO image. fbx64.efi is intended to be installed only on fixed disks as part of a *fallback* boot path in the event that the boot variables have been wiped from the firmware's nvram. It should not be installed on removable media.

Changed in shim (Ubuntu):
importance: Undecided → Low
status: New → Triaged
Revision history for this message
valdikss (valdikss1) wrote :

>However, fbx64.efi should not be included on ISO images

Sorry, my fault, there's no fbx64.efi in that ISO, and it doesn't boot due to unrelated issue.
However, I got an issue with fallback on Fedora, and Ubuntu also buggy version of shim.

To post a comment you must log in.
This report contains Public information  
Everyone can see this information.
Subscribing...

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.