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Unwind the ark signature algorithm pinning#7954

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cjen1-msft wants to merge 6 commits into
microsoft:mainfrom
cjen1-msft:unwind-sig-algo
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Unwind the ark signature algorithm pinning#7954
cjen1-msft wants to merge 6 commits into
microsoft:mainfrom
cjen1-msft:unwind-sig-algo

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@cjen1-msft

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In #7934 we pinned the algorithm for the ark public key. Except we actually pinned the signature algorithm for the ARK.
We already pin the key algorithm as we take the DER encoding of the public key: [bytes + algorithm] and sha256 that.
So this unwinds the extra constraint on the signature algorithm that was unnecessary.

@cjen1-msft cjen1-msft requested a review from a team as a code owner June 18, 2026 07:57
Copilot AI review requested due to automatic review settings June 18, 2026 07:57

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Pull request overview

This PR removes the previously added pinning of the ARK certificate’s signature algorithm during SEV-SNP attestation verification, while still pinning the ARK public key and issuer (which are sufficient given the pinned key material hashing approach described in the PR context).

Changes:

  • Removed the ARK signature-algorithm metadata from the pinned AMD root signing key definitions.
  • Dropped the runtime check that compared the ARK certificate’s signature algorithm against pinned metadata, retaining the issuer check.

Custom instructions used:

  • .github/copilot-instructions.md
  • .github/instructions/reviewing.instructions.md

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File Description
src/pal/attestation.cpp Removes ARK signature-algorithm pinning logic and keeps issuer pinning during SNP report verification.
include/ccf/pal/attestation_sev_snp.h Updates pinned ARK metadata to no longer include a signature-algorithm field.

Comment thread src/pal/attestation.cpp Outdated
Comment on lines 56 to 57
return name;
}
Comment thread src/pal/attestation.cpp
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3 participants