The installer denied NT SERVICE\OtOpcUaScriptWorker only on -InstallRoot. On the wonder layout the node's keys and
secrets sit beside it (E:\ApiInstall\OtOpcUa\pki with the application certificate's private key, data\ with
secrets.db and LocalDb), inheriting BUILTIN\Users:RX. Users is a restricting SID of the worker token, so a worker
could read them.
- Install-ScriptWorkerIsolation.ps1 -DenyPaths <dir>,...: each folder gets the same inherited deny as InstallRoot
(new SensitiveDirDeny steps). Refuses drive/share roots, script-worker\ and the PE cache; folders must exist;
a comma/semicolon string works for powershell -File.
- The deny is read AND write (0xD0157: ReadData, WriteData, AppendData, WriteEA, DeleteChild, WriteAttributes,
Delete, WRITE_DAC, WRITE_OWNER). Traverse/Execute, ReadAttributes, ReadControl and Synchronize stay so the
loader still reaches script-worker\. The write half stops a worker planting a cert in pki\trusted\certs where
a data drive lets Users create files in subfolders.
- The list is recorded under the anchor service's key (Parameters\DenyPaths, step DenyPathRecord): a re-run
removes the deny from folders dropped from the list, -Uninstall removes every recorded one without repeating
-DenyPaths. -WhatIf/-PlanOnly print every step.
- After an apply, WARN for each protected-DACL item under a denied folder that the inherited deny cannot reach;
without -DenyPaths, WARN for pki/data/logs/backup/config/secrets siblings of InstallRoot.
Tests:
- Dry-run harness 46 -> 86 assertions (QA layout plan, mask bits, refusals, stale removal, record-driven
rollback, host account never denied). Mutations (no sibling deny, deny->allow, mask back to ReadData, no
stale removal, rollback ignoring the record, script-worker not refused) each turn it red.
- Test-ScriptWorkerIsolation.Windows.ps1 (Windows PowerShell 5.1, windev): 34/34, incl. -DenyPaths apply,
11/11 unchanged re-apply, shorter-list re-apply, uninstall from the record, second uninstall unchanged.
- New InstallerLayoutIsolationTests (OTOPCUA_ISOLATION_INSTALLER_E2E=1, elevated Windows): a scratch wonder
layout under the real restricted worker token. Before install and after uninstall the token reads pki/data/
logs/backup/appsettings and plants a trust-list file; installed it can do neither, still reads script-worker\,
a real worker launched from the layout runs a script, and the host still reads everything. Mutating the
-DenyPaths denies to a no-op mask turns it red on pki\own\private\otopcua.pfx (reproduces #890).
QA vq03/vq04 are NOT re-applied; the command is in docs/deploy/qa-upgrade-b8b4c18f-to-fea7de0a.md.
Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
Owner decisions §14 #5/#6 as built (design §12.5):
- Scripting:Worker:Identity (default unset, Windows only, fail-closed validation): each worker
starts under a restricted token derived from the host's. Every privilege but SeChangeNotify is
removed; the restricting SIDs are NT SERVICE\OtOpcUaScriptWorker's SID + Everyone + Users +
RESTRICTED; the token and default DACLs are host + SYSTEM + identity + RESTRICTED. The worker
is created suspended, put in its Job Object before it runs, inherits only its stdio pipes, gets
an ACL'd work dir as TEMP, and runs with DOTNET_EnableDiagnostics=0. The identity is granted on
the host's window station and desktop, because USER32 init made coreclr.dll fail with
ERROR_DLL_INIT_FAILED on windev. The logon SID is not used because the host's process DACL
gives it PROCESS_VM_READ.
- The worker pipe on Windows always has an explicit protected DACL: host account + identity
only. There is no owner ACE, so an elevated host's Administrators gets no access.
- The worker treats access denied on its parent-pid poll as alive; the Job Object covers that case.
- scripts/install/Install-ScriptWorkerIsolation.ps1 + ScriptWorkerIsolation.psm1 are idempotent
and support -WhatIf, -Uninstall and -PlanOnly. They create the disabled anchor service, the
PeCacheDir ACL (protected, no Users, key and markers host-only, pe\ Modify for the identity),
read+execute on script-worker\, a ReadData deny on the install root, the outbound firewall
block on the worker exe, and optionally the host-service env.
- Tests: the dry-run harness scripts/install/tests/Test-ScriptWorkerIsolation.ps1 (46
assertions, mutation-checked); ScriptWorkerIdentityTests; WorkerIsolationTests, which cover
the pipe ACL, token access and a real restricted worker running a script, all green on windev.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty