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:
Organization name and website:
Company: HP Development Company
Email: [email protected]
https://www.hp.com
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:
https://eintaxid.com/company/941081436-hp-inc/
Master cert x509 information:
Serial Number: 87:02:80:ee:3e:ad:e5:31 Signature Algorithm: sha256WithRSAEncryption Issuer: C = US, ST = Colorado, L = Fort Collins, O = HP, OU = ThinPro, CN = ThinPro SecureBoot Master CA 2021 Validity Not Before: May 27 22:03:26 2021 GMT Not After : May 25 22:03:26 2031 GMT Subject: C = US, ST = Colorado, L = Fort Collins, O = HP, OU = ThinPro, CN = ThinPro SecureBoot Master CA 2021
HP ThinPro is a Linux distro that is specifically built to run on ThinClients
What's the justification that this really does need to be signed for the whole world to be able to boot it?
Previous ThinPro are only released with HP hardwares support. The next ThinPro release is targeted for not just HP's machines, but also general PC from other vendors. We need our bootloader to be signed by MS UEFI key for it to be bootable there.
HP ThinPro use an LTS kernel built by us to provide a stable/secure foundation for the OS that runs on top of it. We use a set of drivers and new features that are not always available in other kernels.
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: Eniac Zhang
- Position: Software Developer
- Email address: [email protected]
Already verified as part of the previous accepted submission. See rhboot/shim-review#468
- Name: Michael Frick
- Position: ThinPro Program Manager
- Email address: [email protected]
Already verified as part of the previous accepted submission. See rhboot/shim-review#468
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.
Yes, see Dockerfile for confirmation.
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.
https://github.com/eniaczhp/ThinProShim16
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.
N/A
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 rebuild the package base off Ubuntu's implementation (rebuilding Grub with SBAT adapted to differentiate the ThinPro version).
Skip this, if you're not using GRUB2, otherwise make sure these are present and confirm with yes.
We use latest upstream grub package. The grub doesn't support external module loading to minimize the attack surface.
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/?
The current build up the grub sbat level to 5:
sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md grub,5,Free Software Foundation,grub,2.12,https://www.gnu.org/software/grub/ grub.ubuntu,2,Ubuntu,grub2,2.12-1ubuntu7.3,https://www.ubuntu.com/ grub.thinpro,1,HP,grub2,2.12-1ubuntu7.3,https://www.hp.com/
If you had no previous signed shim, say so here. Otherwise a simple yes will do.
Yes. Additionally, our old shims and Grub binaries will be blocked by SBAT policy as well.
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. We are running 6.12.33 kernel now. It has all these fixes.
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.
Yes, we need to add drivers and tweaks for new device support in HP hardwares.
We also frequently backport or cherry-pick bug and security fixes from the linux-stable tree following HP internal security guideline.
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.
An HP cert: thinpro-ko-signing-cert-2020-09.cer is used to allow kernel to load any out-of-tree driver we need. Those drivers are often provided by vendors for latest hardware.
A copy of said cert is added to this repo.
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.
We are re-using the CA certificate, but we've never signed a previous vulnerable GRUB2 binary without SBAT data.
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
This should include logs for creating the buildroots, applying patches, doing the build, creating the archives, etc.
build.log
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.
Most notably is that the grub and kernel are updated. We have two more signed binaries, one to trigger bios firmware updatae (see fwupd) Another to manage MOK key (mmx64.efi)
$ sha256sum shimx64.efi.unsigned 030271c10704af82dca2dafcce243d0926c8352accca308bfc3d1a88d2b5e403 shimx64.efi.unsigned
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. It's hosted in HP's own Secure Signing Service Cloud. Engineer doesn't have access to the key other than using the Signing API provided by the Security team. Every signing operation is authorized and logged.
A yes or no will do. There's no penalty for the latter.
No.
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.
Here are the X509 extensions of that certificate:
X509v3 extensions:
X509v3 Subject Key Identifier:
46:93:54:BE:ED:2F:84:BB:A8:52:8D:53:53:47:78:F2:45:4E:B3:A0
X509v3 Authority Key Identifier:
46:93:54:BE:ED:2F:84:BB:A8:52:8D:53:53:47:78:F2:45:4E:B3:A0
X509v3 Basic Constraints: critical
CA:TRUE
X509v3 Key Usage:
Digital Signature, Certificate Sign, CRL Sign
X509v3 CRL Distribution Points:
Full Name:
URI:https://ftp.hp.com/pub/tcdebian/thinpro-secureboot-master-ca.crl
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 )?
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.
grub:
sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
grub,5,Free Software Foundation,grub,2.12,https://www.gnu.org/software/grub/
grub.ubuntu,2,Ubuntu,grub2,2.12-1ubuntu7.3,https://www.ubuntu.com/
grub.thinpro,1,HP,grub2,2.12-1ubuntu7.3,https://www.hp.com/
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.thinpro,1,HP,shim,16.1,https://www.hp.com/
mm:
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.thinpro,1,HP,shim,16.1,https://www.hp.com/
fwupd:
sbat,1,UEFI shim,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
fwupd-efi,1,Firmware update daemon,fwupd-efi,1.4,https://github.com/fwupd/fwupd-efi
fwupd-efi.thinpro,1,HP ThinPro,hptc-secureboot,3.0,https://www.hp.com/
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.
This is the command we use to build the grub image:
mods := help part_gpt ntfs ntfscomp part_msdos ext2 btrfs exfat fat linux all_video search configfile echo sleep minicmd regexp probe loadenv test loopback chain reboot tpm
grubx64.efi.unsigned: $(efideb)
dpkg -x $(efideb) efideb
dpkg -x $(bindeb) efibin
echo 'cmdpath=$${fw_path}' > grub.cfg.0
echo 'export cmdpath' >> grub.cfg.0
echo 'configfile $${cmdpath}/grub.cfg' >> grub.cfg.0
./efibin/usr/bin/grub-mkimage -o "grubx64.efi.unsigned" -O x86_64-efi -d "efideb/usr/lib/grub/x86_64-efi" -p "(hd0,msdos1)/grub" -c grub.cfg.0 -s grub.sbat $(mods)
rm -rf efideb efibin grub.cfg.0
note that some of those are disabled under lockdown as per the latest set of Grub CVE fixes.
If you are using systemd-boot on arm64 or riscv, is the fix for unverified Devicetree Blob loading included?
Not applicable.
Based on Ubuntu Noble grub2 2.12-1ubuntu7.3
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.
We are also shipping fwupd and mmx.
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.
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 and fwupd does not chainload any other binaries.
Does your shim load any loaders that support loading unsigned kernels (e.g. certain GRUB2 configurations)?
No.
We ship 6.12.33 today with routine upgrade to align with latest LTS kernel
All in-tree modules are built together with the kernel image and signed using an ephemeral RSA key.
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.
We try to keep an eye out for issues or PRs related to the upstream/Debian/Ubuntu side of the ecosystem and participate in other discussions where our contributions seem worthwhile.
N/A