Files
shopdb-flask/agent
cproudlock 852aec5b7f Verify the launch-path hardening on Windows, and fix what that found
The previous commit said the link-resolving change had never met a real
filesystem. Run in the win11 VM against real fixtures, it turned out to reject
EVERY legitimate launch path.

ResolveDirectoryChain walked up looking for a junction and eventually asked
whether "C:\" was a link. That throws DirectoryNotFoundException, and the caller
treats a resolve failure as a rejection, so the first legitimate case came back
"cannot resolve the real path: Could not find a part of the path 'C:\'". The
agent would have failed closed on everything - an outage wearing a security
fix's clothes. It compiled with zero warnings and read correctly.

Stop at the volume root, and never let "cannot tell whether this is a link" turn
into a rejection: TryResolveLink returns null on any failure, and the assembled
path is re-checked against the roots regardless, so an unresolvable component
still cannot widen what is accepted.

One expectation in the probe was mine being wrong rather than the code. 8.3
short names used to be rejected because the lexical prefix check could not match
C:\PROGRA~1 against C:\Program Files - fail closed, but by accident of not
understanding the path rather than by intent. Resolution now expands it to the
real directory, which is inside the approved root, so accepting it is correct.

Verified on Windows, all ten cases:
  accept  a real exe under the approved root
  accept  8.3 short name resolving into the approved root
  reject  exe reached through a junction pointing out of the root
  reject  alternate data stream on a file in the root
  reject  traversal back out of the root
  reject  UNC path
  reject  sibling directory sharing the root's prefix
  reject  wrong extension
  reject  file that does not exist
  reject  empty path

The probe is committed as agent/ShopDbEndpointAgent.PolicyProbe so this is
repeatable. It is NOT in CI and its README says why: junctions, alternate data
streams and 8.3 names do not exist on Linux, and a suite that skipped every case
it exists for would report green and mean nothing. This repo has been bitten by
that shape more than once already.

Scope: product
2026-09-02 16:13:01 -04:00
..

ShopDB Endpoint Agent

A Windows telemetry agent that reports endpoint state to a ShopDB server's endpoints plugin. It runs as a Windows service in production and as a console app for development and testing.

Projects

  • ShopDbEndpointAgent.Core - contracts, config, logging, collection, and the resilient collector HTTP client. No host concerns; unit-testable.
  • ShopDbEndpointAgent - the service host (generic host + Windows service lifetime). Composes Core through DI. This is the telemetry runtime.
  • ShopDbEndpointAgent.Tray - interactive user-session tray app: a system-tray icon with "Send Status now" (on-demand report) and the 5-click issue reporter (ServiceNow flow is still a scaffold). Separate process from the service, because a SYSTEM service cannot draw a tray icon in a user session.

Configuration

Runtime config is layered. Non-secret defaults live in appsettings.json (shipped with the build). The collector key and base URL are provisioned out of band in the registry and win over appsettings.json, so a distributed build never carries the secret and the site can rotate the key without a rebuild.

Registry (production)

Create these values under HKLM\SOFTWARE\GE\ShopDB (64-bit view):

Value Type Meaning
BaseUrl String https://shopdb.example.net (server root)
CollectorKey String The endpoint agent key from Settings -> Endpoints -> Key management

Example (elevated PowerShell):

New-Item -Path 'HKLM:\SOFTWARE\GE\ShopDB' -Force | Out-Null
Set-ItemProperty -Path 'HKLM:\SOFTWARE\GE\ShopDB' -Name 'BaseUrl' -Value 'https://shopdb.example.net'
Set-ItemProperty -Path 'HKLM:\SOFTWARE\GE\ShopDB' -Name 'CollectorKey' -Value '<paste the generated key>'

appsettings.json (all environments)

Key Default Meaning
baseurl "" Dev fallback for the server root (registry wins).
apikey placeholder Dev fallback for the collector key (registry wins).
cadenceseconds 900 Report interval (15 min).
jitterseconds 60 Random +/- spread on the interval (anti-herd).
adoptonfirstrun true Send adopt=true on first contact only.
utilitiespath "" Directory of site PowerShell "agent utilities".
logpath "" Override the rolling log directory.

For a dev box, set baseurl and apikey here and skip the registry.

Running

Console (dev), one report then exit:

dotnet run --project ShopDbEndpointAgent -- --once

Console (dev), continuous cadence loop:

dotnet run --project ShopDbEndpointAgent -- --console

Install as a Windows service

Publish self-contained, then register with sc.exe (elevated):

dotnet publish ShopDbEndpointAgent -c Release -r win-x64 --self-contained -o C:\ProgramData\ShopDB\EndpointAgent\bin
sc.exe create "ShopDBEndpointAgent" binPath= "C:\ProgramData\ShopDB\EndpointAgent\bin\shopdb-endpoint-agent.exe" start= auto DisplayName= "ShopDB Endpoint Agent"
sc.exe description "ShopDBEndpointAgent" "Reports endpoint telemetry to ShopDB."
sc.exe start "ShopDBEndpointAgent"

The service runs as LocalSystem by default, which it needs to read the Security event channel and system WMI.

Tray app (system-tray icon)

The tray is a per-user process, not a service, so it starts at sign-in rather than under sc.exe. install-shopdbagent.ps1 handles it: it copies shopdb-endpoint-tray.exe next to the agent, registers an HKCU logon autostart (Software\Microsoft\Windows\CurrentVersion\Run\ShopDbEndpointTray), and launches it for the current user. Run the installer from the operator's own session so the autostart lands in the right user hive. Pass -NoTray for a headless, service-only install.

Right-click the tray icon for:

  • Send Status now - reports this PC to ShopDB immediately so the monitor page refreshes without waiting for the next cadence tick. It shells out to shopdbagent.exe --once, reusing the exact production collection path; the tray holds no collector key. A balloon tip reflects success or failure (on failure, see the rolling agent log).
  • Report an issue... - the ServiceNow ticket flow (scaffold; submission path is an open decision).

A desktop shortcut to shopdb-endpoint-tray.exe can be added later for an explicitly launchable ServiceNow surface.

WebUI command execution model (security context)

The WebUI can send an endpoint an allowlisted command (server source of truth: plugins/endpoints/commands.py; agent handler: CommandExecutor). The agent service runs as LocalSystem, but not every command runs in that context. The launch context is chosen per action so processes surface to the operator while privileged operations keep the token they need:

  • Generic process_start (for example DncMain, UDC) launches into the ACTIVE CONSOLE USER's session at medium integrity, so the app is visible on the operator's desktop. CyberArk/EPM brokers any elevation afterward.
  • Generic process_stop / process_status run as SYSTEM (kill and probe).
  • service_start / service_stop / service_status run as SYSTEM, because service control requires the admin/SYSTEM token.
  • mtconnect_start / mtconnect_stop / mtconnect_status all run as SYSTEM, because MTConnect is the "UDC MTConnect Agent" Windows service and service control requires the admin/SYSTEM token. mtconnect_start runs install.bat (Agent.exe install) to install or repair the service, then ensures it is running; mtconnect_stop stops the service; mtconnect_status queries it. run.bat (agent.exe run agent.cfg) is a foreground TESTING launcher and is deliberately NOT used by the agent.
  • system_restart runs as SYSTEM and reboots the machine immediately via shutdown.exe /r /t 0 (no grace timer). It is a fixed action with no target, gated server-side by the dedicated endpoints.restart permission on top of endpoints.command, and fronted by a WebUI confirmation gate.

Do not route MTConnect through the generic process_start user-session path or service control breaks. MTConnect is intentionally absent from the process_start launch map for the same reason; the fixed mtconnect_* handler owns it.

Behavior note for redeploys: the MTConnect service-control model is a runtime change, so the agent must be rebuilt and redeployed for it to take effect. Server-side command/allowlist/RBAC changes are picked up by the container rebuild; rebuild and redeploy the agent whenever the runtime launch/control logic itself changes.

Diagnostics

  • Rolling file log: %ProgramData%\ShopDB\EndpointAgent\logs\agent-YYYYMMDD.log (14-day retention).
  • Windows Event Log: agent runtime failures and unhandled exceptions are written to the Application log under source ShopDB Endpoint Agent. The source is created on first elevated run (or by the installer). Filter Event Viewer by that source to see agent/system interop failures.

Agent utilities (PowerShell seam)

If utilitiespath points at a directory, the runtime runs each *.ps1 there per report, parses its JSON stdout, and merges the result into the report. This is the seam the future server-side "Agent configuration" settings page uses to push site-authored collectors down. Scripts must be code-signed and allow-listed before this is enabled in the field (rollout concern).

Logging extensibility

All runtime code logs through Microsoft.Extensions.Logging (ILogger). Adding a sink later (a ShopDB HTTP sink, Seq, syslog) is a host-builder change in Program.cs::ConfigureLogging with no changes to the worker, collector, or client.