Four search-and-read passes against AWS Well-Architected SaaS Lens, Azure
Architecture Center, OWASP, the OpenID Foundation, and PostgreSQL practitioner
literature. Each digest holds one of our ladders against outside practice and
lists its sources.
Headline: the draft-1 -> draft-2 reframe is corroborated. Microsoft states
"isolation is a spectrum, not a discrete property" and derives our E/P coupling
independently. The shape is sound; the details are not.
Five corrections draft-2 needs:
- E3 overclaims. Any session can re-SET the GUC, so RLS is strong against a
forgotten predicate and useless against SQL injection or a compromised
process. The ADR says "the application cannot trivially route around" - the
exact overclaim it prohibits elsewhere.
- The pooling claim in section 16 is backwards. Transaction-scoped SET LOCAL is
what makes E3 safe under pooling; statement-level pooling is what serves
other tenants' rows, only under production concurrency.
- E3 layers on E2 rather than superseding it.
- Placement cannot be expressed per tenant, but the commercial section requires
exactly that - a tier bought by some tenants puts a service at two P levels
at once, which the posture vector cannot represent.
- FORCE ROW LEVEL SECURITY is mandatory: ADR-0001 already established that our
migration role owns the tables it creates, so it would silently bypass every
policy.
Also: pgTAP and pgrls make the E3 evidence artifact far cheaper than assumed;
OWASP publishes a Multi-Tenant Security Cheat Sheet we reference nowhere; our
tenant-boundary gap is BOLA, OWASP API1, top of that list since it launched;
AuthZEN 1.0 went Final in January and flex-auth is pre-standard; and no plane
covers tenant offboarding, which OWASP makes a MUST.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
