First real run of the #780 installer (windev, #800 gate) failed on both hosts and its rollback failed too:
- PowerShell 7: DirectoryInfo.GetAccessControl/SetAccessControl do not exist on .NET. Use Get-Acl / Set-Acl.
- Windows PowerShell 5.1: an if-expression unrolled the wanted ACE to a scalar ($null on -Remove), so .Count threw under
StrictMode. Wrap it in @(...).
- Found on the re-run: an apply from 5.1 was not idempotent. 5.1 passes the literal quotes in sc.exe binPath= with legacy
quoting, so the anchor path was stored unquoted and AnchorService reported 'changed' on every run. sc create/config now
runs through Invoke-OtOpcUaSc with an explicit command line, identical on both hosts.
Adds scripts/install/tests/Test-ScriptWorkerIsolation.Windows.ps1: a Windows-executed dry run -> apply -> re-apply ->
uninstall -> uninstall test (scratch names, stand-in host service) for either host. The plan-only harness cannot see these.
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