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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?

ITRenew Inc

What product or service is this for?

Teraware is a scalable custom data sanitization tool that can be deployed on a variety of platforms and architectures. It comprises an application layer server and a bootable agent that are built to handle a plethora of configurations, from single devices to server farms and data centers via one installation.

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

The Teraware is used by our enterprise, SMB and home customers to process a wide of different models of laptops/PCs/servers. The deployment process is fully automated for these customers. Most of the hardware has Secure Boot enabled by default and may not be disabled in some instances. We are not able to reuse SHIM/GRUB/Kernel from Redhat, or any other distribution, because Teraware software has custom patches for storage drivers. The Linux Kernel must be built and signed with our EV certificate. To establish the full chain of trust we also have to rebuild and sign the SHIM and GRUB loader.

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

We are unable to reuse SHIM from another distro because Teraware software contains custom patches for storage drivers that don't exist in the kernel upstream.

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:David Friedman
  • Position: Senior Manager, IT
  • Email address:david.friedman@ironmountain.com
  • PGP key fingerprint: B2C6438FFDE5A3AAFB8CE3BEA3CD579F25D41BC3

(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:Keith LoPresto
  • Position:Software Development Manager
  • Email address:keithd.lopresto@ironmountain.com
  • PGP key fingerprint: 85F2F52063ABD45CF77E75D4A9FA571827D09E89

(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 15.8 shim release tar?

Please create your shim binaries starting with the 15.8 shim release tar file: https://github.com/rhboot/shim/releases/download/15.8/shim-15.8.tar.bz2

This matches https://github.com/rhboot/shim/releases/tag/15.8 and contains the appropriate gnu-efi source.

yes

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

https://github.com/rhboot/shim/releases/tag/15.8

What patches are being applied and why:

None

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, NX bit is disabled due to the non fully NX-compatible boot stack.

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)

We use the upstream GRUB2 shim_lock verifier.

If shim is loading GRUB2 bootloader and your previously released shim booted a version of GRUB2 affected by any of the CVEs in the July 2020, the March 2021, the June 7th 2022, the November 15th 2022, or 3rd of October 2023 GRUB2 CVE list, have fixes for all these CVEs been applied?

Yes

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?

The entry should look similar to: grub,4,Free Software Foundation,grub,GRUB_UPSTREAM_VERSION,https://www.gnu.org/software/grub/

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?

Previous SHIM 15.7 submission was accepted by review team, but is not signed by Microsoft. We decided to update submission to SHIM version 15.8.

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?

Yes, all these have been applied.

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

Yes. Local patches has been applied to storage drivers: aacraid, megaraid_sas, smartpqi, nvme-core, hpsa. These patches resolves performance and storage device compatibility problems using low-level access to storage devices and disk drives. These patches don't exist in the upstream kernel.

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, we implemented ephemeral key for signing kernel modules with this updated submission.

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.

The new vendor_db functionality is not used.

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.

This is our initial SHIM submission and we are using a new EV certificate. No previously used certificates.

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.

Dockerfile provided. Binaries may be reproduced with command:

docker build --no-cache --tag=shim-review-itrenew .

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' is a log file for our build.

It was produced with command: docker build --no-cache --progress=plain --tag=shim-review-itrenew . &> build.log

What changes were made since your SHIM was last signed?

None. Initial shim creation and review submission

What is the SHA256 hash of your final SHIM binary?

5d94c41b58a14aa5ef9a473db8c3942ca5665e00753bdd41f69ba7bf12cb02a4 shimx64.efi aad7f2f918a105ca4b62dbfe8ad4eee0e62c2fa155b928d6e5c85d2a2655a074 shimia32.efi 956d16026b648a992dd9f155436caa4e7b4f125f1d7c28efb37cdb89689b8ff3 shimaa64.efi

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

The key is stored on a FIPS-140-2 token with restricted physical access to authorized personnel only.

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

Yes. 3 years validity EV certificate issued by Sectigo Limited.

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.

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.itrenew,1,ITrenew Inc.,shim,15.8,mail:security@itrenew.com

GRUB2:

sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
grub,4,Free Software Foundation,grub,2.12,https//www.gnu.org/software/grub/
grub.itrenew,1,ITrenew Inc.,grub2,2.12-5ca9db22e,mail:security@itrenew.com

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

all_video boot chain configfile echo ext2 exfat fat font gfxmenu gfxterm gfxterm_background gzio halt iso9660 jpeg linux loadenv loopback lvm memdisk normal ntfs part_gpt part_msdos png probe reboot search search_fs_file search_fs_uuid search_label test tpm true video xfs

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

Do not use systemd-boot

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

We use upstream GRUB2 bootloader from: https://git.savannah.gnu.org/git/grub.git

Release Version 2.12 Commit: 5ca9db22e8ed0dbebb2aec53722972de0680a463

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

Shim used to launch GRUB only

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.

GRUB only launches the linux kernel

How do the launched components prevent execution of unauthenticated code?

UEFI firmware with Secure Boot enabled will trust to SHIM that will be signed by Microsoft. This SHIM has our company EV certificate embedded. SHIM verifies GRUB bootloader that is signed using our company EV certificate and allows to boot only this GRUB bootloader. GRUB verifies Linux Kernel using the 'shim_lock' verifier and only allows booting of the kernel signed using our EV certificate. Linux Kernel is built with lockdown support and option CONFIG_MODULE_SIG_FORCE enabled to enforce checking of modules signature. All modules we build are signed with our EV certificate.

The above steps establish the full chain of trust.

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

No, GRUB uses the 'shim_lock' verifier to ensure that only kernels signed by us are loaded.

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

We use Linux Kernel 5.15.70. This kernel already has all lockdown patches applied.

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

None