Joseph Doherty
4dc2ad8084
Until now ISqlDialect.QuoteIdentifier was the SOLE defence for authored
table/column names: an identifier went from the TagConfig blob straight into a
command text, bracket-quoted. The residual risk was bounded — a hostile name is
quoted into one nonexistent object, the query fails after the connection opens,
and the tag Bad-codes — but "bounded" is not "filtered", and the design promised
a filter. Both ISqlDialect and SqlServerDialect carried a doc paragraph saying so.
SqlCatalogGate + SqlCatalogLoader now resolve every authored identifier against
the live catalog at Initialize, and REPLACE it with the catalog's own spelling.
The identifier text in an emitted poll query is therefore a string this driver
read back out of ListSchemas/ListTables/ListColumns — not operator input. Quoting
becomes the backstop it was documented to be.
Decisions worth knowing before touching this:
- Substitution, not just validation. Matching is exact-ordinal first, then a
UNIQUE case-insensitive hit: SQL Server's default collation is CI so case
variants have always worked, and rejecting them would break valid deployments.
An ambiguous CI match under a case-sensitive collation is refused rather than
guessed — picking one would publish another column's data under the operator's
node, which is worse than rejecting the tag.
- Charset check BEFORE catalog lookup. Each identifier goes through
QuoteIdentifier for its rejection rules first, so a name carrying a control or
Unicode format character is rejected WITHOUT its value being echoed into a log
line (Trojan-Source). A name that passes is safe to render, which is why
catalog-miss messages do name it — an operator hunting a typo has to see what
they wrote. Both halves are pinned by tests.
- A rejected tag keeps its node. It is dropped from the POLLED table but stays in
the AUTHORED table, so it still materializes and reads BadNodeIdUnknown —
§8.1's specified outcome. My first wiring dropped it from both, which deleted
the node instead; an existing test (ReinitializeAsync_recoversFromFaulted)
caught it. A status code can only be published by a node that exists, and a
missing address-space entry is far harder to diagnose than a Bad quality.
- An unreadable catalog FAULTS Initialize; it does not reject every tag. That is
the absence of evidence about the tags, not evidence against them — rejecting
all of them would serve a confidently-empty address space and send the operator
hunting typos that do not exist. Zero visible schemas is treated the same way,
because that is exactly what a missing GRANT looks like. Faulting lands
DriverInstanceActor in Reconnecting with its retry timer running.
- Bounded load: one schema list, one default-schema scalar, then one ListTables
per distinct authored schema and one ListColumns per distinct authored relation
— never a full catalog enumeration, and nothing after Initialize. Every
authored name reaches the catalog queries as a bound @schema/@table parameter,
so building the allow-list cannot itself be an injection vector.
- ISqlDialect gains DefaultSchemaSql ("SELECT SCHEMA_NAME()"). An unqualified
`TagValues` must resolve in whatever schema the SERVER reports; hardcoding dbo
would be a silent lie on any estate that maps service accounts to their own
default schema. It is a query, not a constant, because the answer is
per-connection.
- Accepted v1 limitation: a 3-part db.schema.table (or linked-server name)
addresses a catalog this connection cannot enumerate, so it cannot be
allow-listed and is rejected with a message pointing at the fix — expose the
data through a view in the connected database.
VerifyLivenessAsync's wall-clock pattern is extracted to RunBoundedAsync and
reused, so the new I/O gets the same R2-01 / STAB-14 protection rather than a
second hand-rolled copy. (It also fixes a latent bug in the extracted code: the
OperationCanceledException arm detached the wrong task.)
Tests: 24 pure gate tests + 9 end-to-end driver tests against the real SQLite
catalog + 3 new live tests against the real SQL Server on 10.100.0.35 (21 in that
suite now pass, exercising the real SELECT SCHEMA_NAME() + INFORMATION_SCHEMA
path). Verified falsifiable: bypassing the gate turns exactly the three rejection
assertions red and leaves the rest green.
SqlInjectionRegressionTests is deliberately NOT rewritten to expect
BadNodeIdUnknown. It drives SqlPollReader directly, below the gate, and pins the
quoting backstop on its own — defence in depth is only worth the name if each
layer holds independently. Rewriting those assertions would delete the backstop's
only coverage and leave the gate a single point of failure. Its scope note, which
said the gate does not exist, is updated to say why it stays where it is.
OtOpcUa documentation
Two tiers of documentation live here:
- Current reference at the top level (
docs/*.md) — describes what's shipped today. Start here for operator + integrator reference. - Implementation history + design notes at
docs/v2/*.md— the authoritative plan + decision log the current reference is built from. Start here when you need the why behind an architectural choice, or when a top-level doc says "see plan.md § X".
The project was originally called LmxOpcUa (a single-driver Galaxy/MXAccess OPC UA server) and has since become OtOpcUa, a multi-driver OPC UA server platform. Any lingering LmxOpcUa-string in a path you see in docs is a deliberate residual (executable name lmxopcua-cli, client PKI folder {LocalAppData}/LmxOpcUaClient/) — fixing those requires migration shims + is tracked as follow-ups.
Platform overview
v2 (2026-05-26): the separate
OtOpcUa.Server+OtOpcUa.Adminservices fused into a single role-gatedOtOpcUa.Hostbinary, joined by an Akka.NET cluster. See v2 design for the architectural decision.
- Core owns shared abstractions (driver capability contracts, scripting, virtual tags, alarm historian).
- Drivers plug in via capability interfaces in
ZB.MOM.WW.OtOpcUa.Core.Abstractions:IDriver,IReadable,IWritable,ITagDiscovery,ISubscribable,IHostConnectivityProbe,IAlarmSource,IHistoryProvider,IPerCallHostResolver. Each driver opts into whichever it supports. - Host (
src/Server/ZB.MOM.WW.OtOpcUa.Host) is the single fused binary (.NET 10, AnyCPU).OTOPCUA_ROLESenv decides what to mount:admin(Blazor + control-plane singletons),driver(OPC UA endpoint + per-node actors), or both. See ServiceHosting.md. - Cluster + ControlPlane + Runtime + AdminUI + Security sit between Core and Host. The cluster glues per-node actors into one logical fleet; the control-plane singletons (deploy coordinator, audit writer, redundancy state) live on the admin role-leader. See Redundancy.md.
- The Galaxy driver still reaches MXAccess via gRPC to a separately-installed mxaccessgw sidecar (sibling repo).
Where to find what
Architecture + data-path reference
| Doc | Covers |
|---|---|
| OpcUaServer.md | Top-level server architecture — Core, driver dispatch, Config DB, generations |
| AddressSpace.md | GenericDriverNodeManager + ITagDiscovery + IAddressSpaceBuilder |
| ReadWriteOperations.md | OPC UA Read/Write → CapabilityInvoker → IReadable/IWritable |
| DriverLifecycle.md | Server-side driver lifecycle + infrastructure contracts (IDriverFactory, IDriverProbe, IDriverSupervisor, IDriverHealthPublisher, IDriverConfigEditor, IHistorianDataSource) + the Commons library |
| Subscriptions.md | Monitored items → ISubscribable + per-driver subscription refcount (v1 archive) |
| AlarmTracking.md | IAlarmSource + AlarmSurfaceInvoker + OPC UA alarm conditions — native Galaxy alarms end-to-end (live) |
| AlarmTracking.md | Original alarm-tracking write-up (v1 archive) |
| AlarmHistorian.md | Core.AlarmHistorian store-and-forward sink — LocalDbStoreAndForwardSink, the replicated alarm_sf_events buffer + Primary-only drain, IAlarmHistorianWriter, dead-letter/retry/eviction |
| DataTypeMapping.md | Per-driver DriverAttributeInfo → OPC UA variable types (v1 archive — live mapping is in src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Browse/DataTypeMap.cs) |
| IncrementalSync.md | Address-space rebuild on redeploy + sp_ComputeGenerationDiff |
| HistoricalDataAccess.md | IHistoryProvider as a per-driver optional capability (v1 archive) |
| VirtualTags.md | Core.Scripting + Core.VirtualTags — Roslyn script sandbox, engine, dispatch alongside driver tags |
| ScriptEditor.md | Monaco script editor — Roslyn-backed IntelliSense (completions, diagnostics, hover, tag-path) for C# virtual-tag scripts; AdminUI/ScriptAnalysis/ backend |
| ScriptedAlarms.md | Core.ScriptedAlarms — script-predicate IAlarmSource + Part 9 state machine |
One Core subsystem is shipped without a dedicated top-level doc; see the section in the linked doc:
| Project | See |
|---|---|
Analyzers (Roslyn OTOPCUA0001) |
security.md § OTOPCUA0001 Analyzer |
Drivers
| Doc | Covers |
|---|---|
| drivers/README.md | Index of the eight shipped drivers + capability matrix |
| drivers/Galaxy.md | Galaxy driver — in-process gRPC client to the mxaccessgw sidecar |
| v1/drivers/Galaxy-Repository.md | Galaxy-specific discovery via the ZB SQL database (v1 archive — the gateway owns this path now) |
For Modbus / S7 / AB CIP / AB Legacy / TwinCAT / FOCAS / OPC UA Client specifics, see v2/driver-specs.md.
Operational
| Doc | Covers |
|---|---|
| Configuration.md | Live appsettings + environment-variable reference (current state) |
| Configuration.md | appsettings bootstrap + Config DB + Admin UI draft/publish (v1 archive — OTOPCUA_GALAXY_* env vars now live in mxaccessgw config) |
| Uns.md | The global /uns master tree — manage Area/Line/Equipment/Tag/VirtualTag fleet-wide; replaces the per-cluster UNS/Equipment/Tags tabs |
| security.md | Transport security profiles, LDAP auth, ACL trie, role grants, OTOPCUA0001 analyzer |
| Redundancy.md | RedundancyCoordinator, ServiceLevelCalculator, apply-lease, Prometheus metrics |
| Reservations.md | Fleet-wide ZTag / SAPID external-ID reservations — publish-time claim, release flow |
| ServiceHosting.md | Single fused OtOpcUa.Host binary install/uninstall with OTOPCUA_ROLES gating; the historian backend is the external HistorianGateway |
| StatusDashboard.md | Pointer — superseded by v2/admin-ui.md |
Client tooling
| Doc | Covers |
|---|---|
| Client.CLI.md | otopcua-cli — OPC UA command-line client |
| Client.UI.md | Avalonia desktop client |
| DriverClis.md | Driver test-client CLIs — index + shared commands |
| Driver.Modbus.Cli.md | otopcua-modbus-cli — Modbus-TCP |
| Driver.AbCip.Cli.md | otopcua-abcip-cli — ControlLogix / CompactLogix / Micro800 / GuardLogix |
| Driver.AbLegacy.Cli.md | otopcua-ablegacy-cli — SLC / MicroLogix / PLC-5 (PCCC) |
| Driver.S7.Cli.md | otopcua-s7-cli — Siemens S7-300 / S7-400 / S7-1200 / S7-1500 |
| Driver.TwinCAT.Cli.md | otopcua-twincat-cli — Beckhoff TwinCAT 2/3 ADS |
| Driver.FOCAS.Cli.md | otopcua-focas-cli — Fanuc FOCAS/2 CNC |
Requirements
| Doc | Covers |
|---|---|
| reqs/HighLevelReqs.md | HLRs — numbered system-level requirements |
| reqs/OpcUaServerReqs.md | OPC UA server-layer reqs |
| v1/reqs/ServiceHostReqs.md | Per-process hosting reqs (v1 archive — only OtOpcUa server hosting remains in scope post-PR-7.2) |
| reqs/ClientRequirements.md | Client CLI + UI reqs |
| v1/reqs/GalaxyRepositoryReqs.md | Galaxy-scoped repository reqs (v1 archive — owned by mxaccessgw today) |
| v1/reqs/MxAccessClientReqs.md | Galaxy-scoped MXAccess reqs (v1 archive — owned by mxaccessgw today) |
| reqs/StatusDashboardReqs.md | Pointer — superseded by Admin UI |
Implementation history (docs/v2/)
Design decisions + phase plans + execution notes. Load-bearing cross-references from the top-level docs:
- v2/plan.md — authoritative v2 vision doc + numbered decision log (referenced as "decision #N" elsewhere)
- v2/admin-ui.md — Admin UI spec
- v2/acl-design.md — data-plane ACL + permission-trie design (Phase 6.2)
- v2/config-db-schema.md — Config DB schema reference
- v2/driver-specs.md — per-driver addressing + quirks for every shipped protocol
- v2/dev-environment.md — dev-box bootstrap
- v2/test-data-sources.md — integration-test simulator matrix (includes the pinned libplctag
ab_serverversion for AB CIP tests) - v2/multi-host-dispatch.md — per-PLC circuit breakers (Phase 6.1 decision #144)
- v2/v2-release-readiness.md — release-readiness tracker
- v2/phase-7-status.md — Phase 7 reconciliation: what shipped vs. the plan, and the five remaining gaps
- v2/implementation/phase--.md — per-phase execution plans with exit-gate evidence
v1 archive
The v1 in-process MXAccess architecture (Galaxy.Host + Galaxy.Proxy + Galaxy.Shared, .NET 4.8 x86 COM, the OtOpcUaGalaxyHost Windows service) was retired in PR 7.2 (2026-04-30, commit ae7106d). Docs that described that shape are kept under v1/ as historical record — see v1/README.md for the index.