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Publish approval_binding_digest: a claim cannot name the request carrying it
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secrets-engine confirmed T03, and re-verifying against the regenerated
destroy fixture found something neither repository can fix alone: a
pdp_digest recorded at issue time can never equal the request_digest of a
request that carries the claim in its context, because the claim is part
of the context that is hashed. Embedding the claim changes the very
digest the claim would need to name.

Not fixture staleness. It holds for every dual-control request whose
claim travels in context -- the shape GH-DEC-2026-008 had just ruled
mandatory. Left unresolved that ruling was unimplementable for exactly
the case it was written for, and destroy would have been permanently
un-allowable in production, failing closed forever on a check that could
never pass.

flex-auth owns the canonical request digest, so the fix is ours.
binding.approval_binding_digest is the same material with
context.approval removed, emitted only when a claim was carried. An
approval issued against a claim-free Check records that Check's
request_digest; the claim-bearing request reproduces it here.

DELIBERATELY ADDITIVE, and the reason matters. The tempting fix is to
drop context.approval from request_digest entirely. That is wrong:
request_digest is the replay identity, and two requests differing only in
which approval was presented must not share one, because their decisions
differ -- one allows, the other denies dual_control_required. Collapsing
them would let an allow obtained with a valid claim be replayed against a
request carrying none. So request_digest still covers the claim and still
moves; approval_binding_digest deliberately does not, and is documented
as not a replay identity. The tests assert the two functions DISAGREE on
a claim-bearing request, which is approval-engine's formulation of how to
defend a distinction that looks like duplication.

The fixture now demonstrates the property rather than asserting it: its
claim's pdp_digest equals the envelope's approval_binding_digest with
pdp_path true, and changing the claim's contents moved request_digest
while leaving approval_binding_digest untouched. Two files a consumer can
diff.

Also picked up approval-engine's new required binding.pdp_path via the
cross-repo schema test added yesterday -- which is the test doing exactly
what it was built for, one day later.

T03 is done. secrets-engine's own digest-material defect, which our two
real envelopes caught, is recorded in the workplan.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JTbVXpEiXA7mNJVpDnEPcB

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 412054@bnt-lap001
Assistant-Session: 3968fae1-8d59-4209-9bd6-c22594b8ab19
This commit is contained in:
tegwick 2026-09-06 14:52:33 +02:00
parent 9f3e7e363a
commit dd3ce4c109
13 changed files with 631 additions and 85 deletions
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3
examples/secrets-engine/check_request_allow_destroy_dual_control.json
View file

@ -36,7 +36,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",

21
examples/secrets-engine/policy_fixtures.yaml
View file

@ -355,7 +355,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",
@ -443,7 +444,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",
@ -503,7 +505,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",
@ -563,7 +566,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",
@ -623,7 +627,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",
@ -683,7 +688,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",
@ -743,7 +749,8 @@
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",

3
examples/secrets-engine/policy_package.md
View file

@ -347,7 +347,8 @@ valid_claim := {
"principal": "bernd",
"purpose": "rotate-exposed-key",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56"
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true
},
"freshness": {
"observed_at": "2026-09-06T12:00:00+00:00",

21
examples/secrets-engine/replay/README.md
View file

@ -23,13 +23,30 @@ go run ./cmd/flex-auth check \
| Field | `rotate` | `destroy` |
| --- | --- | --- |
| `binding.request_digest` | `sha256:de67324f…4345` | `sha256:fc155db…bdf3` |
| `binding.request_digest` | `sha256:de67324f…4345` | `sha256:c749ee2…091a` |
| `provenance.policy_package_digest` | `sha256:fe0070b7…bd8c` | same |
| `provenance.registry_snapshot_digest` | `sha256:f5a309bc…40bb` | same |
| `provenance.input_claim_digests.context` | absent (empty context) | `sha256:b0d2203…c221` |
| `provenance.input_claim_digests.context` | absent (empty context) | `sha256:8b73d29…2800` |
Verified identical across two runs.
| `binding.approval_binding_digest` | absent (no claim) | `sha256:fa07bec…cd56` |
That last row is the value an approval's `pdp_digest` must equal — never
`request_digest`, which a claim can never match on the request that carries it.
It equals the `request_digest` of the same request with `context.approval`
removed, which is verifiable from this directory: strip the context from
`../check_request_allow_destroy_dual_control.json`, re-run `check`, and the
claim-free request digest is the same value (it denies `dual_control_required`,
which is the point).
**This fixture verifies itself.** The claim inside the request carries
`binding.pdp_digest` equal to the envelope's `approval_binding_digest`, and
`binding.pdp_path: true`. Compare the two values in the two files. Note that
`request_digest` moved when the claim's contents changed while
`approval_binding_digest` did not — that is the stability property, demonstrated
in the artifact rather than asserted in prose.
**Not stable:** `id`, `provenance.decision_time`, and `lifetime.not_before` /
`lifetime.expires_at` move with the clock. `lifetime.ttl` is `15m` from the
package's `allow_ttl`. Do not pin the record as a whole.

16
examples/secrets-engine/replay/decision_destroy_dual_control.json
View file

@ -1,5 +1,5 @@
{
"id": "decision:395efe37c5066e8a",
"id": "decision:44a40c339a020772",
"contract_version": "flex-auth.decision-record.v1",
"request_id": "check:secrets-engine-destroy",
"effect": "allow",
@ -72,7 +72,8 @@
"action": "secrets.kv.destroy",
"actor": "agt-secrets-engine",
"digest": "sha256:3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f3f",
"pdp_digest": "sha256:570d112890586d3cbf00c0e81c85ae7806f40f00afa1a2c0a23fd5e077a27f56",
"pdp_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56",
"pdp_path": true,
"principal": "bernd",
"purpose": "rotate-exposed-key",
"target": {
@ -98,13 +99,14 @@
}
}
},
"request_digest": "sha256:fc155dba88f8ab18b3032ed086ba2f455158c6981106e7829d520ab7b036bdf3"
"request_digest": "sha256:c749ee2dc3cdf927a70a3e5b27cff4d97a438d3264153b4b2e3bcacbaf82091a",
"approval_binding_digest": "sha256:fa07becfaa471394d06aee5fa3cd66352bf0cc69ef24900240489684cda8cd56"
},
"lifetime": {
"kind": "ttl",
"ttl": "15m",
"not_before": "2026-09-06T12:18:21Z",
"expires_at": "2026-09-06T12:33:21Z"
"not_before": "2026-09-06T12:51:16Z",
"expires_at": "2026-09-06T13:06:16Z"
},
"diagnostics": {
"action": "destroy",
@ -122,9 +124,9 @@
"policy_package_digest": "sha256:fe0070b79f66442ae6c218697a49c470c6c8f670aa57a30c078a5284d097bd8c",
"registry_snapshot_digest": "sha256:f5a309bc0b36721fd6d9ad7f53eb21222162bc2eac62a0ab0802a9a1d51340bb",
"input_claim_digests": {
"context": "sha256:b0d2203cd2b43a9ba573c21c038154c131afba4255e313affd7ecf810e2cc221"
"context": "sha256:8b73d29ecef286d42e03d2420531d6c45219f325a7ae004c1ecfc781203a2800"
},
"decision_time": "2026-09-06T12:18:21Z"
"decision_time": "2026-09-06T12:51:16Z"
},
"caring": {
"profile": "caring-0.4.0-rc2",