rhboot/shim-reviewReviews of shim
This repo is for review of requests for signing shim. To create a request for review:
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.
As of 20 October 2025, shims sent to Microsoft will be signed with the 2011 and 2023 keys. For each shim you submit, you will receive two copies back, each signed by a different key. Here is the latest information from Microsoft: https://techcommunity.microsoft.com/blog/hardware-dev-center/signing-with-the-new-2023-microsoft-uefi-certificates-what-submitters-need-to-kn/4455787
New signing requirements have also taken effect, and are available here: https://techcommunity.microsoft.com/blog/hardware-dev-center/updated-microsoft-uefi-signing-requirements/1062916 Please note that undergoing this shim review exempts you from yearly security audits, as long as your shim only hands off to open source boot loaders.
Hint: check the docs directory in this repo for guidance on submission and getting your shim signed.
Here's the template:
Organization name and website:
[your text here]
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)
[your text here]
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)
Example:
Issuer: O=MyIssuer, Ltd., CN=MyIssuer EV Code Signing CA
Subject: C=XX, O=MyCompany, Inc., CN=MyCompany, Inc.
[your text here]
[your text here]
[your text here]
[your text here]
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.
Please upload the PGP keys to a well-known keyserver like keyserver.ubuntu.com and/or include them in the review as an .asc file, and point to them here.
Please create your shim binaries starting with the 16.1 shim release tar file: https://github.com/rhboot/shim/releases/download/16.1/shim-16.1.tar.bz2
This matches https://github.com/rhboot/shim/releases/tag/16.1 and contains the appropriate gnu-efi source.
Make sure the tarball is correct by verifying your download's checksum (SHA256, SHA512) with the following ones:
46319cd228d8f2c06c744241c0f342412329a7c630436fce7f82cf6936b1d603 shim-16.1.tar.bz2
ca5f80e82f3b80b622028f03ef23105c98ee1b6a25f52a59c823080a3202dd4b9962266489296e99f955eb92e36ce13e0b1d57f688350006bba45f2718f159fb shim-16.1.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.
[your text here]
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.
[your url here]
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.
[your text here]
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.
[your text here]
Skip this, if you're not using GRUB2.
[your text here]
Skip this, if you're not using GRUB2, otherwise make sure these are present and confirm with yes.
[your text here]
Skip this, if you're not using GRUB2, otherwise do you have an entry in your GRUB2 binary similar to:
grub,5,Free Software Foundation,grub,GRUB_UPSTREAM_VERSION,https://www.gnu.org/software/grub/?
[your text here]
If you had no previous signed shim, say so here. Otherwise a simple yes will do.
[your text here]
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).
[your text here]
Hint: If it does not, we are not likely to sign your shim.
[your text here]
[your text here]
[your text here]
[your text here]
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.
[your text here]
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.
[your text here]
This should include logs for creating the buildroots, applying patches, doing the build, creating the archives, etc.
[your text here]
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.
[your text here]
[your text here]
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.
[your text here]
A yes or no will do. There's no penalty for the latter.
[your text here]
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.
[your text here]
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 --dump-section .sbat=/dev/stdout YOUR_EFI_BINARY to get these entries. Paste them here. Preferably surround each listing with three backticks (```), so they render well.
[your text here]
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.
[your text here]
[your text here]
[your text here]
Hint: The most common case here will be a firmware updater like fwupd.
[your text here]
Skip this, if you're not using GRUB2 or systemd-boot.
[your text here]
Summarize in one or two sentences, how your secure bootchain works on higher level.
[your text here]
[your text here]
[your text here]
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.
[your text here]
[your text here]