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This repo is for review of requests for signing shim. To create a request for review:

  • clone this repo
  • edit the template below
  • add the shim.efi to be signed
  • add build logs
  • add any additional binaries/certificates/SHA256 hashes that may be needed
  • commit all of that
  • tag it with a tag of the form "myorg-shim-arch-YYYYMMDD"
  • push that to github
  • file an issue at https://github.com/rhboot/shim-review/issues with a link to your tag
  • approval is ready when the "accepted" label is added to your issue

Note that we really only have experience with using GRUB2 on Linux, so asking us to endorse anything else for signing is going to require some convincing on your part.

Here's the template:


What organization or people are asking to have this signed?


Certus Software S.R.L.


What product or service is this for?


Certus Erasure (https://www.certus.software/en/certus-erasure-for-storage-devices/)


What's the justification that this really does need to be signed for the whole world to be able to boot it?


The main reason for this is to easier the effort of Certus Erasure user when booting the software products on machines where he needs to securely remove the data from the attached storage devices. The most affected users are the technicians working with the ITAD companies which are required to remove the data stored on a great amount of machines, on a daily basis.


Why are you unable to reuse shim from another distro that is already signed?


Reusing the shim of another distribution would also require reusing the grub and kernel. We have to build our own kernel.


Who is the primary contact for security updates, etc.?

The security contacts need to be verified before the shim can be accepted. For subsequent requests, contact verification is only necessary if the security contacts or their PGP keys have changed since the last successful verification.

An authorized reviewer will initiate contact verification by sending each security contact a PGP-encrypted email containing random words. You will be asked to post the contents of these mails in your shim-review issue to prove ownership of the email addresses and PGP keys.


(Key should be signed by the other security contacts, pushed to a keyserver like keyserver.ubuntu.com, and preferably have signatures that are reasonably well known in the Linux community.)


Who is the secondary contact for security updates, etc.?


(Key should be signed by the other security contacts, pushed to a keyserver like keyserver.ubuntu.com, and preferably have signatures that are reasonably well known in the Linux community.)


Were these binaries created from the 15.7 shim release tar?

Please create your shim binaries starting with the 15.7 shim release tar file: https://github.com/rhboot/shim/releases/download/15.7/shim-15.7.tar.bz2

This matches https://github.com/rhboot/shim/releases/tag/15.7 and contains the appropriate gnu-efi source.


We confirm that our shim binaries are built from the referenced tarball.


URL for a repo that contains the exact code which was built to get this binary:


https://github.com/rhboot/shim/releases/tag/15.7


What patches are being applied and why:


Backport upstream commit 657b2483ca6e9fcf2ad8ac7ee577ff546d24c3aa to fix issue #533. (Make sbat_var.S parse right with buggy gcc/binutils) Backport upstream commit a53b9f7ceec1dfa1487f4d675573449c5b2a16fb to fix issue #307. (Enable the NX compatibility flag by default)


If shim is loading GRUB2 bootloader what exact implementation of Secureboot in GRUB2 do you have? (Either Upstream GRUB2 shim_lock verifier or Downstream RHEL/Fedora/Debian/Canonical-like implementation)


Using upstream GRUB2 with shim_lock verifier.


If shim is loading GRUB2 bootloader and your previously released shim booted a version of grub affected by any of the CVEs in the July 2020 grub2 CVE list, the March 2021 grub2 CVE list, the June 7th 2022 grub2 CVE list, or the November 15th 2022 list, have fixes for all these CVEs been applied?

  • CVE-2020-14372

  • CVE-2020-25632

  • CVE-2020-25647

  • CVE-2020-27749

  • CVE-2020-27779

  • CVE-2021-20225

  • CVE-2021-20233

  • CVE-2020-10713

  • CVE-2020-14308

  • CVE-2020-14309

  • CVE-2020-14310

  • CVE-2020-14311

  • CVE-2020-15705

  • CVE-2021-3418 (if you are shipping the shim_lock module)

  • CVE-2021-3695

  • CVE-2021-3696

  • CVE-2021-3697

  • CVE-2022-28733

  • CVE-2022-28734

  • CVE-2022-28735

  • CVE-2022-28736

  • CVE-2022-28737

  • CVE-2022-2601

  • CVE-2022-3775


Yes.


If these fixes have been applied, have you set the global SBAT generation on your GRUB binary to 3?


Yes.


Were old shims hashes provided to Microsoft for verification and to be added to future DBX updates?

Does your new chain of trust disallow booting old GRUB2 builds affected by the CVEs?


First time submission, upstream GRUB2 and shim 15,6 have all above CVEs fixed.


If your boot chain of trust includes a Linux kernel:


Yes.


Do you build your signed kernel with additional local patches? What do they do?


No additional local patches, just custom config.


If you use vendor_db functionality of providing multiple certificates and/or hashes please briefly describe your certificate setup.

If there are allow-listed hashes please provide exact binaries for which hashes are created via file sharing service, available in public with anonymous access for verification.


We do not use this functionality.


If you are re-using a previously used (CA) certificate, you will need to add the hashes of the previous GRUB2 binaries exposed to the CVEs to vendor_dbx in shim in order to prevent GRUB2 from being able to chainload those older GRUB2 binaries. If you are changing to a new (CA) certificate, this does not apply.

Please describe your strategy.


N/A, first time submission.


What OS and toolchain must we use to reproduce this build? Include where to find it, etc. We're going to try to reproduce your build as closely as possible to verify that it's really a build of the source tree you tell us it is, so these need to be fairly thorough. At the very least include the specific versions of gcc, binutils, and gnu-efi which were used, and where to find those binaries.

If the shim binaries can't be reproduced using the provided Dockerfile, please explain why that's the case and what the differences would be.


docker build . --no-cache


Which files in this repo are the logs for your build?

This should include logs for creating the buildroots, applying patches, doing the build, creating the archives, etc.

build_log.txt


What changes were made since your SHIM was last signed?


N/A, first time submission.


What is the SHA256 hash of your final SHIM binary?


0f2802ed2653323c1376e4345b49f4d5bc0f3c4348dbd2a91964df3eb345c5d9


How do you manage and protect the keys used in your SHIM?


Keys are stored in a FIPS 140-2 certified HW token provided by Certification Authorities.


Do you use EV certificates as embedded certificates in the SHIM?


Yes.


Do you add a vendor-specific SBAT entry to the SBAT section in each binary that supports SBAT metadata ( grub2, fwupd, fwupdate, shim + all child shim binaries )?

Please provide exact SBAT entries for all SBAT binaries you are booting or planning to boot directly through shim.

Where your code is only slightly modified from an upstream vendor's, please also preserve their SBAT entries to simplify revocation.


Yes.

shim SBAT:

sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
shim,3,UEFI shim,shim,1,https://github.com/rhboot/shim
shim.certus,1,Certus Software S.R.L.,shim,15.7,mail:security@certussoftware.ro

grub SBAT:

sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
grub,3,Free Software Foundation,grub,2.06,https://www.gnu.org/software/grub/
grub.debian,1,Debian,grub2,2.06-5,https://tracker.debian.org/pkg/grub2
grub.certus,1,Certus Software S.R.L.,grub2,2.06-5,mail:security@certussoftware.ro

Which modules are built into your signed grub image?


iso9660 linux normal search efi_gop efi_uga all_video gfxmenu linuxefi


What is the origin and full version number of your bootloader (GRUB or other)?


2.06-5 from https://salsa.debian.org/grub-team/grub/-/tree/debian/2.06-5/debian


If your SHIM launches any other components, please provide further details on what is launched.


N/A


If your GRUB2 launches any other binaries that are not the Linux kernel in SecureBoot mode, please provide further details on what is launched and how it enforces Secureboot lockdown.


N/A


How do the launched components prevent execution of unauthenticated code?


Our shim launches grub2 built with secure-boot support.


Does your SHIM load any loaders that support loading unsigned kernels (e.g. GRUB)?


It launched grub, nothing else.


What kernel are you using? Which patches does it includes to enforce Secure Boot?


Kernel 5.15.42 and has secure boot enabled.


Add any additional information you think we may need to validate this shim.


N/A