Add a command which gets the System Lockdown mode information

[TravisEz13]

Summary of the new feature / enhancement

We should have a command which gets all the Lockdown mode information. The Lockdown Policy. The current language module and the startup language mode of the session.

• A module may not want to support lockdown mode, it would need to know the policy to implement that as the customer may mark the script as trusted and cause it to run in FLM. Perhaps because it cannot be implemented without arbitrary code execution issues.
• Although the current language mode can be gotten, it would be good to have all the information from one place.
• The initial language mode can be anything in a hosted environment. I don't have a use for this right now, but I don't see any reason to exclude it right now. It might be useful for testing that hosted environments in lockdown machines are created correctly.

> get-lockdowninfo             
LockdownPolicy CurrentLanguageMode InitialLanguageMode
-------------- ------------------- -------------------
None           FullLanguage        FullLanguage

Proposed technical implementation details (optional)

Here is a script which gets the information, but the actual one should be in C#, in PowerShell, so that it works when in lockdown mode.

class LockdownInfo {
    [string]$LockdownPolicy
    [string]$CurrentLanguageMode
    [string]$InitialLanguageMode
    LockdownInfo([string]$policy, [string]$clm, [string]$ilm) {
        $this.LockdownPolicy = $policy
        $this.CurrentLanguageMode = $clm
        $this.InitialLanguageMode = $ilm
    }
}
$spType = [psobject].assembly.GetType("System.Management.Automation.Security.SystemPolicy")
$slpMethod = $spType.GetMethod("GetSystemLockdownPolicy")
$lockdownPolicySetting = $slpMethod.Invoke($null, $null)
$currentLM = $ExecutionContext.Host.Runspace.LanguageMode
$initialLM = $ExecutionContext.Host.Runspace.InitialSessionState.LanguageMode
[LockdownInfo]::new($lockdownPolicySetting, $currentLM, $initialLM)

[rhubarb-geek-nz]

If the language modes are unrelated to the system lockdown mode

SystemEnforcementMode GetSystemLockdownPolicy

then I don't see why they should be returned.

Isn't this just a one-liner?

PS> [System.Management.Automation.Security.SystemPolicy]::GetSystemLockdownPolicy()
None

I would suggest it is more related to Get-ExecutionPolicy than languages.

[jdhitsolutions]

Submitted for Working Group review

[rhubarb-geek-nz]

I have made a minimalist package for PSGallery from github.