test(contract): add the §10.1 rule-8 guardrail regression tests - #16
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CONTRACT.md §10.1 rule 8 — "subject of the decision" — was the one part of the local-verification set with no regression test outside PHP, TypeScript and Python. §15.1 hand-verified that every guard rejects correctly, so this closes a missing guardrail rather than a live defect. Rules 1-7 ask whether the token is good. Rule 8 asks whether it is the token the decision is even about. SEC-085 satisfied all seven and was still an authentication bypass: the PHP guard routed a failed verification into a second, successful one against the application's own session, admitting the caller as the app's service account. Each test asserts its precondition rather than assuming it: a second, fully valid credential for a more privileged principal is first shown to pass the same guard, so a fallback would genuinely have succeeded. Without that, the tests would pass merely because nothing was available to substitute — the trap the PHP reference test documents at length. Every test was falsified by injecting the SEC-085 fallback into the guard and confirming it fails. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01SkTHvZQMV47t3UwkEtmB1D
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Adds the CONTRACT.md §10.1 rule-8 guardrail regression tests — the one part of the local-verification set with no test outside PHP, TypeScript and Python.
The rule
Rules 1-7 ask whether the token is good. Rule 8 asks whether it is the token the decision is even about. SEC-085 satisfied all seven and was still an authentication bypass: the PHP guard routed a failed verification into a second, successful one against the application's own session, admitting the caller as the app's service account — in an IAM integration typically far more privileged than the user whose request it replaced.
Why this SDK matters more than most
Unlike the Go/Python/TypeScript guards, which are handed a bare verifier and a tenant, the Ktor plugin holds a full
AxiamClient(config.client) and callsclient.verifySession(token)on it. That is precisely the structural shape SEC-085 exploited — a stateful client, carrying its own session, reachable from the guard.verifySessionis correct today: it decides on the supplied token alone. But nothing pinned that, and the client's session sits one method call away.Making the substitution genuinely reachable
The tests log the client in, so its cookie jar holds a real session token for
app-service-account, and assert that precondition before testing anything. Without that priming the tests would pass against the vulnerable shape for an incidental reason — the fallback would fail because there was no session to fall back to — which is the trap the PHP reference test documents at length.Tests (3)
a failed caller token is rejected even when the client session is healthy— four rejection shapes (expired, garbage,alg:none, foreign tenant), each asserting 401 and that the app's principal never appears as the identity.verifySession decides on the supplied token and never the client session— pins the seam directly, so the guard's correctness doesn't rest on which client method it happens to call today. This is the assertion that would have caught SEC-085 at its source rather than at the framework bridge.a rejected caller has no identity attached to the call— SEC-085 was a bypass rather than a mere error because the request continued carrying an identity.Falsified: injecting the SEC-085 fallback into
verifySessionfails all 3.Verified locally:
./gradlew testgreen (full suite).🤖 Generated with Claude Code
https://claude.ai/code/session_01SkTHvZQMV47t3UwkEtmB1D
Generated by Claude Code