feat(tee): SEV-SNP attestation verifier (Tier 3) - #21
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Implement real AMD SEV-SNP attestation appraisal, all fail-closed: - ca2a_runtime.tee.sev_snp: ATTESTATION_REPORT parsing (measurement, report data, ECDSA-P384 signature) and SevSnpProvider (attest requires a real SEV-SNP guest; detect() is False otherwise). - ca2a_verify.sev_snp: VCEK certificate chain verification (ARK -> ASK -> VCEK to a trusted AMD root), ECDSA-P384 report-signature verification over the report body, and measurement/report-data binding. Validation: the certificate-chain path is exercised against the genuine AMD Milan ARK/ASK root chain fetched from AMD KDS (tests/fixtures/sev_snp/). The report-signature path is exercised end to end with a synthetic VCEK and report, since a real report plus VCEK pair requires SEV-SNP hardware. Tamper, wrong measurement, untrusted root, broken chain, and malformed inputs all fail closed. TDX and TPM backends remain Tier 3. Suite: 70 passed, 3 skipped, 99% coverage. Closes #2 Closes #5 Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This was referenced Jul 1, 2026
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What
First Tier 3 attestation backend: a real, fail-closed AMD SEV-SNP verifier.
ca2a_runtime.tee.sev_snp: parses the SEV-SNPATTESTATION_REPORT(measurement, report data, ECDSA-P384 signature) and addsSevSnpProvider(report generation requires a real SEV-SNP guest;detect()is False otherwise).ca2a_verify.sev_snp: VCEK certificate chain verification (ARK -> ASK -> VCEKto a trusted AMD root), ECDSA-P384 report-signature verification over the report body, and measurement / report-data binding.Validation
Per the agreed approach (real vectors with synthetic fallback):
tests/fixtures/sev_snp/).Tamper, wrong measurement, untrusted root, broken chain, unsupported algorithm, and short reports all fail closed. Suite: 70 passed, 3 skipped, 99% coverage.
Scope / honesty
TDX and TPM backends remain Tier 3 (tracked in #3, #4). End-to-end validation against real hardware vectors and unblocking claim C6 remain open (#6). LIMITATIONS, ROADMAP, and the attestation spec are updated to state exactly what is validated vs pending.
Closes #2
Closes #5
🤖 Generated with Claude Code