Description

Begin using Sigstore signatures for container signing in RHEL / UBI.

Detailed Sigstore rationale and background here.

Goals

Adopting sigstore for signing RHEL/UBI based containers provides a more ergonomic experience for users and is in line with wider container-signing plans.

RHEL/UBI 7/8/9 will continue to have simple-signatures. RHEL 10 images would be sigstore only.

Note: simple-signing code will not be removed from RHEL container tools, so any user re-signing workflows will continue to function.

Requirements

All supported versions of RHEL container tools in RHEL and in layered products must have the code paths and correctly configured policy in order to use UBI10 containers from RHEL9 based systems.

SME: Miloslav Trmac

Decisions and discussions as led by Laurie Friedman and Olga Ksenzova - October 15, 2024

Here are the summary and decisions for RHEL 10.0 GA sigstore support. Full details, recording, and action items are here: https://docs.google.com/document/d/15Gu1003-0nmLNfoEjT4h73JOYJxwRJLaYjPLfFnTHlg/edit

Summary / Decisions:

• All Non-deprecated RHEL images will be dual signed with gpg and sigstore keys before RHEL 10.0 GA, May-13-2025. Konflux and Pub are already dual signing images. Older, non-deprecated RHEL images have manually been dual signed.
• RHEL 10.0 GA will validate sigstore signatures by default
  • We need to continue to dual sign RHEL 10 images with gpg and sigstore until RHEL 9 EOL.
• RHEL 8, 9, 10-Beta images will validate gpg signatures by default
  • Customers can change their configuration to validate a different signature by default
• The internal instance of Rekor is available and setup for sigstore.
  • Rekor does not need to be FIPS compliant.
• The goal is to have RHEL 10.0 sigstore signature verification ready for CTC1 testing, Nov-11
• There are tickets open to track infrastructure work - OCP doc tracking sigstore work
• Container-tools is in feature freeze right now; CNCF is #1 priority per Mike McGrath - minor updates for sigstore support can be planned
• Keys:
  • The sigstore signing and Rekor public keys will be in the “redhat-release” RPM
  • We have 1 sigstore key that we will use for all RHEL sigstore signed images
  • Sigstore signing key is posted on signing keys page now: https://access.redhat.com/security/team/key
    • This is release key 3. It is the sigstore public key
  • Rekor public key: https://tuf-default.apps.rosa.rekor-prod.2jng.p3.openshiftapps.com/targets/rekor.pub
    • TBD where the Rekor public key will be posted - Need ProdSec to decide; this is not a blocker for dev / test
  • PM / ProdSec has a paper trail of how we created keys and who approved them for any future audits: https://issues.redhat.com/browse/SIGNSERVER-1394
• Post-Quantum Proof Cryptography (PQC) is unrelated to sigstore. We will need another PQC safe key pair when we support PQC.  PQC is out of scope for RHEL 10.0 GA.

Testing:  The QE team will have to acquire the sigstore key and validate that the RHEL images are pullable and have basic functionality using it.  This should be the same testing that is currently done with the GPG key, just an additional run using the Sigstore key.