With Security:Acl:Enabled=true, a session holding any grant narrower than
Cluster could not browse the served address space at all — confirmed by the
live gate.
Mechanism. Both realm trees hang under ONE anchor folder minted in
CreateAddressSpace: NodeId("OtOpcUa", <raw ns>). ResolveParentFolder parents
every top-level raw folder AND every top-level UNS area under it, and the
Browse override throws BadUserAccessDenied for the WHOLE call when its source
node is denied. DataPlaneAuthorizer.BuildScope split that identifier like a
path, producing {Kind: Raw, Segments: ["OtOpcUa"]} — but trie grant paths are
["raw", <RawPath segments…>] and "OtOpcUa" is never a path segment, so
PermissionTrie.HasBrowseTransit failed at the realm-child lookup and
CollectMatches yielded only Cluster-scoped grants. Deny, at the front door.
The trie already handled a zero-segment scope as "the realm root, itself an
ancestor of everything granted in that realm" (PermissionTrie.cs:101-118) —
no production path had ever produced that scope. This wires it up.
- V3NodeIds.SharedRootFolderId names the anchor identity; CreateAddressSpace
now mints the NodeId/BrowseName/DisplayName from it (behaviour-identical,
makes the coupling explicit).
- BuildScope maps that identifier (realm-qualified to Raw — in the UNS
namespace s=OtOpcUa is an ordinary Area) onto the zero-segment Raw scope.
- Evaluate adds a second-realm OR-leg for Browse on the anchor only: it fronts
both trees, so a principal whose only Browse grant lives in the UNS tree
still enters through this raw node. Browse only; transit confers navigation,
never read/write/subscribe.
- No trie, evaluator or builder change. No reordering above the decision cache
— key revocation is still re-checked before the lookup — and the cache key
is unchanged (the combined verdict caches under the anchor's own
identifier/realm; a generation advance clears it).
Falsifications actually run (implement-then-revert-the-line, plus one
genuine red-first):
- DataPlaneAuthorizerTests: the 7 new facts were written BEFORE the fix and 4
went red (the 3 deny-only ones passed vacuously, as a deny-only test must).
- Deleting the UNS OR-leg reddens exactly one fact,
The_shared_root_folder_is_browsable_on_a_uns_only_browse_grant (26/27 pass).
- Dropping the realm qualification from IsSharedRootFolder reddens exactly
A_uns_area_named_like_the_anchor_gets_no_anchor_semantics. Its first draft
did NOT catch this — a raw-only grant is refused either way; the
discriminating grant had to be an unrelated UNS one, whose own transit marks
the zero-segment UNS scope the un-qualified mapping would land on.
- Disabling the BuildScope anchor branch reddens the new end-to-end fact
NodeManagerStage6EnforcementTests.The_shared_root_folder_is_browsable_on_a_narrow_grant_and_still_filters
(real booted server, real Browse dispatch: BadUserAccessDenied on the whole
call), which also pins that the reference filter still withholds the
non-granted sibling.
- Core PermissionTrieBrowseTransitTests gains 3 characterization facts pinning
the previously-dead realm-root branch (transit true for the granting realm's
root, false for the other realm's, false without the Browse bit). These were
green on arrival — the trie was always correct; nothing called it.
Tests: Core 351 -> 354 passed; OpcUaServer 482 -> 490 passed. Build clean.
`Security:Acl:Enabled` (default false) makes scoped `NodeAcl` grants decide
data-plane authorization at the three seams that have one, and gives HistoryRead
a check it never had. Read, Browse and Subscribe stay ungated — stage 6.
The ACL decision REPLACES the server-wide role check rather than chaining with
it. Chained, a grant would have to confer the role as well as pass the scope
check, and only Cluster-scoped grants confer a role — so every narrow grant
would have stayed inert and the flag would have looked inert too. The
load-bearing test is an ALLOW: a session carrying no roles at all writing
successfully on the strength of its grant. A deny-only test passes against a
build where the ACL is never consulted, because the role gate denies too.
Found en route: the principal never reached the session. The authenticator
passed it as OpcUaUserAuthResult.DisplayName, but RoleCarryingUserIdentity
derives DisplayName from the presented token — for a key-bearing client that is
the static username `apikey`, identical fleet-wide. So the trie's matching key
was dropped at the identity boundary, and the audit ClientUserId on a rejected
write recorded `apikey` for every consuming system. Principal and ApiKeyId are
now carried explicitly.
Beyond the stage as sketched:
- Revocation reaches an OPEN session. Every decision re-checks the
authenticating key against the current snapshot; without it a key revoked by a
deployment kept its authority until the client chose to reconnect, which for a
machine-to-machine consumer can be indefinitely.
- UserAuthorizationState is built per CALL, not per session. The per-session
shape exists so an LDAP session can re-resolve membership that changed out of
band; nothing can change out of band under API keys, so the generation stamp is
the whole invalidation signal and a per-call record picks it up for free.
IsStale/NeedsRefresh therefore cannot fire here and are documented as vestigial.
- The trie is built inside DataPlaneAuthorityState.Apply, under the same
generation as the snapshot, rather than by a second wiring at the publish
actor. An uninstalled trie denies everything — indistinguishable from working
enforcement. Deleting the install turns 13 of the 22 new tests red.
- The deploy log reports what the BUILD dropped instead of re-deriving it. The
old count agreed with the builder on one of its four drop reasons; a rule with
a blank ScopeId, a retired scope kind, or a path not starting at a realm
vanished with the log reading zero.
Both IApiKeyStore implementations widened to the full grant set. The narrowing
was redundant — ApiKeyInterimRoleMapper applies the same filter itself — and
became a trap once scope was enforced. Pinned by asserting the roles are
unchanged, with the two grants carrying different flags so it cannot pass by
accident.
Falsified by mutation: enforcement never engaging, the write seam ignoring the
ACL, the realm dropped from the scope, the revocation check removed, and the
trie never installed each turn the intended tests red and no others.
Full solution suite green.
Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
Joseph Doherty