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

  • clone this repo (preferably fork it)
  • 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 it 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 or systemd-boot on Linux, so asking us to endorse anything else for signing is going to require some convincing on your part.

Hint: check the docs directory in this repo for guidance on submission and getting your shim signed.

Here's the template:

What organization or people are asking to have this signed?

Organization name and website: VyOS Networks (VyOS Inc)

12585 Kirkham Ct, Suite 1 Poway, California 92604 United States of America

Email: sales@vyos.io https://vyos.io

What's the legal data that proves the organization's genuineness?

The reviewers should be able to easily verify, that your organization is a legal entity, to prevent abuse. Provide the information, which can prove the genuineness with certainty.

Company/tax register entries or equivalent: (a link to the organization entry in your jurisdiction's register will do)

https://opencorporates.com/companies/us_ca/4578449

The public details of both your organization and the issuer in the EV certificate used for signing .cab files at Microsoft Hardware Dev Center File Signing Services. (not the CA certificate embedded in your shim binary)

Issuer: O = SSL Corp, CN = SSL.com EV Code Signing Intermediate CA RSA R3
Subject: C = US, VyOS Networks (VyOS Inc), CN = VyOS Inc

What product or service is this for?

VyOS is a fully open-source, enterprise-grade router platform.

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

VyOS is a software only product. We do not control our users systems/hardware.

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

VyOS is Debian (bookworm - and soon trixie) based. We have our own custom Kernel built by us to provide a stable experience for our (enterprise) users.

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.

  • Name: Christian Breunig
  • Position: Software Developer
  • Email address: christian@breunig.cc
  • PGP key fingerprint: 98D3 C8D2 EEF1 896E EBB5 260C 034E 04D5 3FB8 7A81

(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.?

  • Name: Daniil Baturin
  • Position: Chief Technology Officer
  • Email address: daniil@baturin.org
  • PGP key fingerprint: E8AE FF29 318E EAEB A007 2538 0FBA 4E27 36B7 F57A

(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 16.0 shim release tar?

Please create your shim binaries starting with the 16.0 shim release tar file: https://github.com/rhboot/shim/releases/download/16.0/shim-16.0.tar.bz2

This matches https://github.com/rhboot/shim/releases/tag/16.0 and contains the appropriate gnu-efi source.

Make sure the tarball is correct by verifying your download's checksum with the following ones:

7b518edd63eb840081912f095ed1487a  shim-16.0.tar.bz2
c2453b9b3c02bc01eea248e9cf634a179ff8828c  shim-16.0.tar.bz2
d503f778dc75895d3130da07e2ff23d2393862f95b6cd3d24b10cbd4af847217  shim-16.0.tar.bz2
b4367f3b1e0716d093f4230902e392d3228bd346e2e07a9377c498d8b3b08a5c0ad25c31aa03af66f54648618074a29b55a3e51925e5cfe5c7ac97257bd25880  shim-16.0.tar.bz2

Make sure that you've verified that your build process uses that file as a source of truth (excluding external patches) and its checksum matches. You can also further validate the release by checking the PGP signature: there's a detached signature

The release is signed by the maintainer Peter Jones - his master key has the fingerprint B00B48BC731AA8840FED9FB0EED266B70F4FEF10 and the signing sub-key in the signature here has the fingerprint 02093E0D19DDE0F7DFFBB53C1FD3F540256A1372. A copy of his public key is included here for reference: pjones.asc

Once you're sure that the tarball you are using is correct and authentic, please confirm this here with a simple yes.

A short guide on verifying public keys and signatures should be available in the docs directory.

yes

URL for a repo that contains the exact code which was built to result in your binary:

Hint: If you attach all the patches and modifications that are being used to your application, you can point to the URL of your application here (https://github.com/YOUR_ORGANIZATION/shim-review).

You can also point to your custom git servers, where the code is hosted.

What patches are being applied and why:

Mention all the external patches and build process modifications, which are used during your building process, that make your shim binary be the exact one that you posted as part of this application.

Patch from rhboot/shim#739

Some VyOS releases will get secure-boot enabled later in their release cycle but are based on Debian Bookworm and we wan't to reuse the signed SHIM.

Do you have the NX bit set in your shim? If so, is your entire boot stack NX-compatible and what testing have you done to ensure such compatibility?

See https://techcommunity.microsoft.com/t5/hardware-dev-center/nx-exception-for-shim-community/ba-p/3976522 for more details on the signing of shim without NX bit.

No, not yet - we are waiting for the rest of our boot stack to support it before enabling it.

What exact implementation of Secure Boot in GRUB2 do you have? (Either Upstream GRUB2 shim_lock verifier or Downstream RHEL/Fedora/Debian/Canonical-like implementation)

Skip this, if you're not using GRUB2.

We re-use Debians version of GRUB2 - this is why we also include the Debian Secure Boot CA in this shim binary for maximum compatibility.

Do you have fixes for all the following GRUB2 CVEs applied?

Skip this, if you're not using GRUB2, otherwise make sure these are present and confirm with yes.

Yes - we're reusing Debian 12 and Debian 13 GRUB2 versions

If shim is loading GRUB2 bootloader, and if these fixes have been applied, is the upstream global SBAT generation in your GRUB2 binary set to 4?

Skip this, if you're not using GRUB2, otherwise do you have an entry in your GRUB2 binary similar to:
grub,4,Free Software Foundation,grub,GRUB_UPSTREAM_VERSION,https://www.gnu.org/software/grub/?

We're reusing Debian 12 and Debian 13 GRUB2 versions

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?

If you had no previous signed shim, say so here. Otherwise a simple yes will do.

No previous signed shim

If your boot chain of trust includes a Linux kernel:

Is upstream commit 1957a85b0032a81e6482ca4aab883643b8dae06e "efi: Restrict efivar_ssdt_load when the kernel is locked down" applied?

Is upstream commit 75b0cea7bf307f362057cc778efe89af4c615354 "ACPI: configfs: Disallow loading ACPI tables when locked down" applied?

Is upstream commit eadb2f47a3ced5c64b23b90fd2a3463f63726066 "lockdown: also lock down previous kgdb use" applied?

Hint: upstream kernels should have all these applied, but if you ship your own heavily-modified older kernel version, that is being maintained separately from upstream, this may not be the case.
If you are shipping an older kernel, double-check your sources; maybe you do not have all the patches, but ship a configuration, that does not expose the issue(s).

Yes - our Kernels are 6.6 or higher

How does your signed kernel enforce lockdown when your system runs

with Secure Boot enabled?

Hint: If it does not, we are not likely to sign your shim.

Using all the standard upstream mechanisms/security features, most prominently the lockdown LSM.

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

Yes. https://github.com/vyos/vyos-build/tree/current/scripts/package-build/linux-kernel/patches/kernel

These include networking patches and inotify support for stackable filesystems.

Do you use an ephemeral key for signing kernel modules?

If not, please describe how you ensure that one kernel build does not load modules built for another kernel.

Yes

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.

In addition to our VyOS Networks Secure Boot CA we also embed the Debian Secure Boot CA in order to re-use their bianry components like GRUB2.

If you are re-using the CA certificate from your last shim binary, you will need to add the hashes of the previous GRUB2 binaries exposed to the CVEs mentioned earlier to vendor_dbx in shim. Please describe your strategy.

This ensures that your new shim+GRUB2 can no longer chainload those older GRUB2 binaries with issues.

If this is your first application or you're using a new CA certificate, please say so here.

This is out first application

Is the Dockerfile in your repository the recipe for reproducing the building of your shim binary?

A reviewer should always be able to run docker build . to get the exact binary you attached in your application.

Hint: Prefer using frozen packages for your toolchain, since an update to GCC, binutils, gnu-efi may result in building a shim binary with a different checksum.

If your shim binaries can't be reproduced using the provided Dockerfile, please explain why that's the case, what the differences would be and what build environment (OS and toolchain) is being used to reproduce this build? In this case please write a detailed guide, how to setup this build environment from scratch.

Yes

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.

What changes were made in the distro's secure boot chain since your SHIM was last signed?

For example, signing new kernel's variants, UKI, systemd-boot, new certs, new CA, etc..

Skip this, if this is your first application for having shim signed.

SKIP - first application

What is the SHA256 hash of your final shim binary?

64c945dd275a6d95cb97a79a208b3ddcc6fb42706e67de58206c77d023c7ef99

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

Describe the security strategy that is used for key protection. This can range from using hardware tokens like HSMs or Smartcards, air-gapped vaults, physical safes to other good practices.

The keys are stored on a FIPS certified HSM with restricted access.

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

A yes or no will do. There's no penalty for the latter.

No

Are you embedding a CA certificate in your shim?

A yes or no will do. There's no penalty for the latter. However, if yes: does that certificate include the X509v3 Basic Constraints to say that it is a CA? See the docs for more guidance about this.

Yes

For the well known Debian Secure Boot CA

X509v3 extensions:
    Authority Information Access:
        CA Issuers - URI:https://dsa.debian.org/secure-boot-ca
    X509v3 Authority Key Identifier:
        6C:CE:CE:7E:4C:6C:0D:1F:61:49:F3:DD:27:DF:CC:5C:BB:41:9E:A1
    Netscape Cert Type: critical
        SSL Client, SSL Server, S/MIME, Object Signing, SSL CA, S/MIME CA, Object Signing CA
    X509v3 Extended Key Usage:
        Code Signing
    X509v3 Key Usage: critical
        Digital Signature, Certificate Sign, CRL Sign
    X509v3 Basic Constraints: critical
        CA:TRUE
    X509v3 Subject Key Identifier:
        6C:CE:CE:7E:4C:6C:0D:1F:61:49:F3:DD:27:DF:CC:5C:BB:41:9E:A1

For VyOS Networks Secure Boot CA

X509v3 extensions:
    X509v3 Subject Key Identifier:
        78:99:6C:D5:B5:0A:E3:7A:C8:DB:82:85:DF:94:6F:57:F1:D1:E5:46
    X509v3 Authority Key Identifier:
        78:99:6C:D5:B5:0A:E3:7A:C8:DB:82:85:DF:94:6F:57:F1:D1:E5:46
    X509v3 Basic Constraints: critical
        CA:TRUE

Do you add a vendor-specific SBAT entry to the SBAT section in each binary that supports SBAT metadata ( GRUB2, fwupd, fwupdate, systemd-boot, systemd-stub, shim + all child shim binaries )?

Please provide the exact SBAT entries for all binaries you are booting directly through shim.

Hint: The history of SBAT and more information on how it works can be found here. That document is large, so for just some examples check out SBAT.example.md

If you are using a downstream implementation of GRUB2 (e.g. from Fedora or Debian), make sure you have their SBAT entries preserved and that you append your own (don't replace theirs) to simplify revocation.

Remember to post the entries of all the binaries. Apart from your bootloader, you may also be shipping e.g. a firmware updater, which will also have these.

Hint: run objcopy --only-section .sbat -O binary YOUR_EFI_BINARY /dev/stdout to get these entries. Paste them here. Preferably surround each listing with three backticks (```), so they render well.

shim:

sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
shim,4,UEFI shim,shim,1,https://github.com/rhboot/shim
shim.vyos,1,VyOS,shim,16.0,https://github.com/vyos/efi-boot-shim.git

If shim is loading GRUB2 bootloader, which modules are built into your signed GRUB2 image?

Skip this, if you're not using GRUB2.

Hint: this is about those modules that are in the binary itself, not the .mod files in your filesystem.

all_video boot btrfs cat chain configfile cpuid cryptodisk echo
efifwsetup efinet ext2 f2fs fat fdt font gcry_arcfour gcry_blowfish
gcry_camellia gcry_cast5 gcry_crc gcry_des gcry_dsa gcry_idea gcry_md4
gcry_md5 gcry_rfc2268 gcry_rijndael gcry_rmd160 gcry_rsa gcry_seed
gcry_serpent gcry_sha1 gcry_sha256 gcry_sha512 gcry_tiger gcry_twofish
gcry_whirlpool gettext gfxmenu gfxterm gfxterm_background gzio
halt help hfsplus http iso9660 jfs jpeg keystatus linux loadenv
loopback ls lsefi lsefimmap lsefisystab lssal luks luks2 lvm mdraid09
mdraid1x memdisk minicmd normal ntfs part_apple part_gpt part_msdos
password_pbkdf2 peimage play png probe raid5rec raid6rec reboot regexp
search search_fs_file search_fs_uuid search_label serial sleep smbios
squash4 test tftp tpm true video xfs zfs zfscrypt zfsinfo

If you are using systemd-boot on arm64 or riscv, is the fix for unverified Devicetree Blob loading included?

We only support amd64/x86_64 at the moment.

What is the origin and full version number of your bootloader (GRUB2 or systemd-boot or other)?

  • grub-efi-amd64 (2.06-13+deb12u1)

If your shim launches any other components apart from your bootloader, please provide further details on what is launched.

Hint: The most common case here will be a firmware updater like fwupd.

Not applicable

If your GRUB2 or systemd-boot 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.

Skip this, if you're not using GRUB2 or systemd-boot.

It will only launch Linux in SecureBoot mode.

How do the launched components prevent execution of unauthenticated code?

Summarize in one or two sentences, how your secure bootchain works on higher level.

GRUB is built with SecureBoot support, the Linux kernel with Lockdown support.

systemd-boot is currently not used

Does your shim load any loaders that support loading unsigned kernels (e.g. certain GRUB2 configurations)?

No

What kernel are you using? Which patches and configuration does it include to enforce Secure Boot?

Currently 6.6 - soon 6.12 or newer LTS version.

Relevant KConfig values:

CONFIG_MODULE_SIG=y
CONFIG_MODULE_SIG_FORCE=y
CONFIG_MODULE_SIG_ALL=y
CONFIG_MODULE_SIG_SHA512=y
CONFIG_MODULE_SIG_HASH="sha512"
# CONFIG_TRUSTED_KEYS is not set
CONFIG_MODULE_SIG_KEY="certs/signing_key.pem"
CONFIG_MODULE_SIG_KEY_TYPE_RSA=y
CONFIG_SYSTEM_TRUSTED_KEYRING=y
CONFIG_SYSTEM_TRUSTED_KEYS=""

We might add an intermediate key to CONFIG_SYSTEM_TRUSTED_KEYS for additional module signing.

What contributions have you made to help us review the applications of other applicants?

The reviewing process is meant to be a peer-review effort and the best way to have your application reviewed faster is to help with reviewing others. We are in most cases volunteers working on this venue in our free time, rather than being employed and paid to review the applications during our business hours.

A reasonable timeframe of waiting for a review can reach 2-3 months. Helping us is the best way to shorten this period. The more help we get, the faster and the smoother things will go.

For newcomers, the applications labeled as easy to review are recommended to start the contribution process.

I tried to read up as much other applications for a SHIM to understand your work and effort and not waste anyones time.

I plan to start by reviewing issues tagged easy to review to contribute.

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

Thank you for your effort!

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