#Requires -RunAsAdministrator
#Requires -Version 5
#Requires -Modules Microsoft.PowerShell.LocalAccounts

[CmdletBinding()]

Param (
    # Whether or not to enable debugging messages
    [bool]$EnableDebug = $true,

    # Username for remote administration account
    [String]$ServiceUser = "{{ winrm_remote_user }}",

    # Default password for this account
    [String]$ServicePassword = "{{ winrm_bootstrap_password }}"
)

Set-StrictMode -Version 2 # don't force v3

[bool]$HasSSL = $false
$ServiceUserDescription = "Service user for remote administration"



function Log($Message, [String]$Color = $null, $NoNewline = $false) {
    if ($Color) {
        $ExtraParms = @{"ForegroundColor" = $Color}
    } else {
        $ExtraParms = @{}
    }

    Write-Host $Message @ExtraParms -NoNewline:$NoNewline
}

function Debug($Message) {
    if ($EnableDebug) {
        Log $Message -Color Cyan
    }
}

function Change($Message) {
    Log "! $Message" -Color Yellow
}

function Error($Message) {
    Log "ERROR: $Message" -Color Red
    Exit
}

function Assert($Condition, $Message) {
    if (!$Condition) {
        Error -Message $Message
    }
}

function Count($E) {
    return ($E | Measure).Count
}

function New-Credential($User, $Password) {
    return New-Object System.Management.Automation.PSCredential($User, (ConvertTo-SecureString $Password -AsPlainText -Force))
}










# Checks service account for compliance

function Verify-LocalUser($User) {
    $Name = $User.Name
    Debug "Verifying account `"$Name`""

    # Is it enabled?
    if (!$User.Enabled) {
        Change "Enabling account `"$Name`""
        $User | Enable-LocalUser -ErrorAction Stop
    }

    # Check if account is set to never expire
    if ($User.AccountExpires -ne $null) {
        Change "Changing account expiration policy for `"$Name`""
        $User | Set-LocalUser -AccountNeverExpires -ErrorAction Stop
    }

    # Do the same with its password
    if ($User.PasswordExpires -ne $null) {
        Change "Changing password expiration policy for `"$Name`""
        $User | Set-LocalUser -PasswordNeverExpires -ErrorAction Stop
    }

    # Account description is not really important but it doesn't hurt to check
    if ($User.Description -ne $ServiceUserDescription) {
        Change "Changing description for `"$Name`""
        $User | Set-LocalUser -Description $ServiceUserDescription -ErrorAction Stop
    }

    # Validate group membership for Administrators group
    if ((Get-LocalGroupMember -SID S-1-5-32-544 | select -ExpandProperty SID) -notcontains $User.SID.Value) {
        Change "Changing group membership for `"$Name`" - adding account to `"Administrators`" local group"
        Add-LocalGroupMember -SID S-1-5-32-544 -Member $User -ErrorAction Stop
    }

    # Do the same for RMS group, if it exists
    if ((Get-LocalGroupMember -SID S-1-5-32-580 | select -ExpandProperty SID) -notcontains $User.SID.Value) {
        if (Get-LocalGroup -SID S-1-5-32-580 -ErrorAction SilentlyContinue) {
            Change "Changing group membership for `"$Name`" - adding account to `"Remote Management Users`" local group"
            Add-LocalGroupMember -SID S-1-5-32-580 -Member $User -ErrorAction Stop
        }
    }

    Debug "Verification complete"
}





# PROCESS:
# Find, create, edit group membership of service account and validate it
# DESIRED STATE: an active service account on local machine

function Process-ServiceAccount {
    Debug "* Processing: Service account"

    # Verify if there is already an user
    $User = Get-LocalUser -Name $ServiceUser -ErrorAction SilentlyContinue

    if ($User) {
        Log "Found existing service account: `"$ServiceUser`""
    } else {
        # Create new user and verify it
        Debug "No service account found, will create one"

        # Handle passwordless user (may be useful for pure cert auth, not really the case now)
        if ($ServicePassword -eq $null -or $ServicePassword.Length -eq 0) {
            $PasswordSplat = @{
                "NoPassword" = $true
            }

            Log "Using passwordless login"
        } else {
            $PasswordSplat = @{
                "Password" = ConvertTo-SecureString $ServicePassword -AsPlainText -Force
                "PasswordNeverExpires" = $true
            }
        }

        # Create an user
        try {
            $User = New-LocalUser -Name $ServiceUser `
                                  -Description $ServiceUserDescription `
                                  -AccountNeverExpires `
                                  @PasswordSplat
        } catch {
            Error "Caught an exception while creating service account `"$ServiceUser`""
        }
        Assert $User "Failed to create service account `"$ServiceUser`""
        Change "Created service account `"$ServiceUser`""


        # Add this user to Administrators local group
        try {
            Add-LocalGroupMember -SID S-1-5-32-544 -Member $User -ErrorAction Stop
        } catch {
            Error "Caught an exception while adding service account `"$ServiceUser`" to local group `"Administrators`""
        }
        Change "Added account `"$ServiceUser`" to local group `"Administrators`""


        # Check if RMU group exists
        if (!(Get-LocalGroup -SID S-1-5-32-580 -ErrorAction SilentlyContinue)) {
            Log "`"Remote Management Users`" group is missing from this system - will not add user to this group" -Color Yellow
        } else {

            # Also add user to RMU local group
            try {
                Add-LocalGroupMember -SID S-1-5-32-580 -Member $User -ErrorAction Stop
            } catch {
                Error "Caught an exception while adding service account `"$ServiceUser`" to local group `"Remote Management Users`""
            }
            Change "Added account `"$ServiceUser`" to local group `"Remote Management Users`""
        }
    }

    # Verify user, no matter whether it was found or created
    Verify-LocalUser -User $User
}





# PROCESS:
# Ensure that local network connection profile category is set to Private, so firewall rules and Enable-PSRemoting should work correctly
# Network interface are selected by their DNS suffix
# DESIRED STATE: category of local network interface is set to Private

function Process-NetworkProfile {
    Debug "* Processing: Network Profiles"

    $Interfaces = gwmi -Class Win32_NetworkAdapterConfiguration -Filter IPEnabled=TRUE -ComputerName .

    {% if old_corp_tld is defined -%}
    # workaround for old corp tld
    $Interfaces = $Interfaces | ? { ($_.DNSDomain -match ".*{{ int_tld }}$") -or ($_.DNSDomain -match ".*{{ old_int_tld }}$") }
    {%- else -%}
    $Interfaces = $Interfaces | ? { $_.DNSDomain -match ".*{{ int_tld }}$" }
    {%- endif %}

    if (!$Interfaces) {
        # early return if there is no compatible network interface
        Log -Color Yellow "Failed to find local network interface with corp DNS suffix - skipping network profile check"
    } else {
        Debug "Found $(Count $Interfaces) compatible network interfaces"

        $Interfaces.InterfaceIndex | % {
            if ((Get-NetConnectionProfile -InterfaceIndex $_).NetworkCategory -eq "Public") {
                Change "Setting network category of interface #$_ to Private"

                try {
                    Set-NetConnectionProfile -InterfaceIndex $_ -NetworkCategory "Private" -ErrorAction Stop
                } catch {
                    Error "Caught an exception when setting network profile category"
                }
            }
        }
    }
}





# PROCESS:
# Start up WinRM service and ensure that it has automatic start type
# DESIRED STATE: WinRM service is running and is set to auto-start on next boot

function Process-WinRM {
    Debug "* Processing: WinRM"

    try {
        $Service = Get-Service -Name "WinRM"
        Assert $Service "WinRM service does not exist on this machine"

        if ($Service.StartType -ne "Automatic") {
            Change "Setting WinRM startup type to Automatic"
            $Service | Set-Service -StartupType Automatic -ErrorAction Stop
        }

        if ($Service.Status -in "Stopped", "StopPending") {
            Change "Starting WinRM service"
            $Service | Start-Service -ErrorAction Stop
        }
    } catch {
        Error "Caught an exception while setting up WinRM service"
    }
}







# PROCESS:
# Set LocalAccountTokenFilterPolicy registry value to 1
# DESIRED STATE: LocalAccountTokenFilterPolicy = 1

function Process-Registry {
    Debug "* Processing: Registry"

    $Key = "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System"
    $Name = "LocalAccountTokenFilterPolicy"
    $Value = 1

    $Prop = Get-ItemProperty $Key -ErrorAction SilentlyContinue

    if (!$Prop) {
        Error "Parent registry key for $Name does not exist, skipping this step"
    } else {
        $M = Get-Member -InputObject $Prop -name $Name -Membertype Properties -ErrorAction SilentlyContinue
        if (!$M -or $Prop.$Name -ne $Value) {
            Log "$Name is set to an incorrect value or is empty"

            Remove-ItemProperty $Key -Name $Name -Force -ErrorAction SilentlyContinue
            Change "Removed $Name from $Key"

            Assert ((New-ItemProperty $Key -Name $Name -PropertyType "DWord" -Value $Value).$Name -eq $Value) "Failed to create `"$Name`" registry property"
            Change "Added $Name to $Key with value $Value"
        }
    }
}






# PROCESS:
# Enable PS Remoting
# DESIRED STATE: there is at least one session configuration and a WSMan listener (their validity will be checked later)

function Process-PSRemoting {
    Debug "* Processing: PS Remoting"

    # This snippet was mostly taken from Ansible script
    # TODO: most of remoting stuff is already taken care of - this function is just a failsafe
    if (!(Get-PSSessionConfiguration -Verbose:$false) -or !(Get-ChildItem WSMan:\localhost\Listener)) {
        Log "No PS session configuration or listener found - enabling PS remoting"

        # Override local verbose preference
        $Pref = $VerbosePreference
        $VerbosePreference = "SilentlyContinue"

        try {
            Enable-PSRemoting -Force -ErrorAction Stop -Verbose:$false > $null
        } catch {
            Error "Caught an exception in Enable-PSRemoting"
        }

        Change "PS Remoting enabled"

        # Set verbose preference back to its original value
        $VerbosePreference = $Pref
    }
}








# Create a HTTP listener
function Create-HTTPListener {
    New-Item 'WSMan:\localhost\Listener' -Transport HTTP -Address "*" -Force > $null
    Change "Created HTTP listener"
}

function Verify-Listener($Listener) {
    return ($Listener -and `
            ($Listener.Keys -contains "Transport=HTTP" -or $Listener.Keys -contains "Transport=HTTPS") -and `
            $Listener.Keys -contains "Address=*")
}


# PROCESS:
# Loop through PS listeners and ensure there's only one active HTTP listener
# (this ignores HTTPS listeners because they will be set up by Ansible later)
# DESIRED STATE: there is an active HTTP listener

function Process-Listeners {
    Debug "* Processing: WSMan listeners"

    # Find valid listeners and also save all listeners
    $All = Get-ChildItem WSMan:\localhost\Listener
    $Valid = $All | ? {Verify-Listener -Listener $_}

    if ((Count $All) -eq 1 -and (Count $Valid) -eq 1) {
        Log "Found 1 listener: `"$($Valid[0].Name)`"" # only one: either http (ok) or https (also ok)
    } else {
        # Remove all listeners
        $All | % {
            Change "Removing listener: `"$($_.Name)`""
            try {
                $_ | Remove-Item -Force -Recurse
            } catch {
                # Continue even if an exception has happened
                Log -Color Yellow "Caught an exception while removing listener `"$($_.Name)`""
            }
        }

        # Create
        Create-HTTPListener

        # Verify after creation
        $Valid = Get-ChildItem WSMan:\localhost\Listener | ? {Verify-Listener -Listener $_}
        Assert ((Count $Valid) -eq 1) "Listener was just created, but it's missing"
        Debug "Found listener after creation"
    }

    $Listener = $Valid[0]
}



# PURPOSE:
# Search, validate and fix PS session configurations
# This also sets up a more secure SDDL
# DESIRED STATE: PS session configurations are validated and are now correct

function Process-SessionConfig {
    Debug "* Processing: PS Session Configuration"

    $SDDL = "O:NSG:BAD:P(A;;GA;;;RM)(A;;GA;;;IU)S:P(AU;FA;GA;;;WD)(AU;SA;GXGW;;;WD)"
    Get-PSSessionConfiguration | ? {$_.Name -eq "microsoft.powershell" -or $_.Name -eq "microsoft.powershell32"} | % {

        if ($_.SecurityDescriptorSddl -ne $SDDL) {
            Change "Changing SDDL on session configuration `"$($_.Name)`""

            try {
                ($_ | Set-PSSessionConfiguration -SecurityDescriptorSddl $SDDL) > $null
            } catch {
                Log -Color Yellow "Caught an exception while changing SDDL on `"$($_.Name)`""
            }
        }
    }
}




function Process-PSRAuth {
    Debug "* Processing: PS Remoting Authentication"

    $Auth = Get-ChildItem WSMan:\localhost\Service\Auth

    "Basic","Kerberos","Certificate" | % {
        if (($Auth | ? Name -eq $_).Value -eq $true) {
            Change "Disabling $_ authentication"
            Set-Item -Path "WSMan:\localhost\Service\Auth\$_" -Value $false
        }
    }

    if (($Auth | ? Name -eq "CredSSP").Value -eq $false) {
        Change "Enabling CredSSP authentication"
        Enable-WSManCredSSP -Role Server -Force > $null
    }
}



function Process-Firewall {
    Debug "* Processing: PS Remoting Firewall"

    if (Get-NetFirewallRule -Name "WINRM-HTTPS-In-TCP" -ErrorAction SilentlyContinue) {
        Debug "Found HTTPS rule, will disable HTTP rules"
        $Script:HasSSL = $true

        Get-NetFirewallRule -ErrorAction SilentlyContinue | ? {$_.Name -like "WINRM-HTTP-*" -and $_.Enabled -eq $true} | % {
            Change "Disabling firewall rule for PSR over HTTP: $($_.DisplayName)"
            Disable-NetFirewallRule -Name $_.Name
        }
    } else {
        Debug "HTTPS rule is missing, will add HTTP rule"
        $Script:HasSSL = $false

        if (!(Get-NetFirewallRule -Name "WINRM-HTTP-In-TCP" -ErrorAction SilentlyContinue)) {
            Change "Adding firewall rule for PSR over HTTP"

            New-NetFirewallRule -Name "WINRM-HTTP-In-TCP" `
                            -DisplayName "Windows Remote Management (HTTP-In)" `
                            -Description "Inbound rule for Windows Remote Management via WS-Management. [TCP 5985]" `
                            -Group "Windows Remote Management" `
                            -Program "System" `
                            -Protocol TCP `
                            -LocalPort "5985" `
                            -RemoteAddress "{{ int_net }}" `
                            -Action Allow `
                            -Profile Domain,Private > $null
        }

        $Rule = Get-NetFirewallRule -Name "WINRM-HTTP-In-TCP" -ErrorAction SilentlyContinue
	if (!$Rule) {
            Error "HTTP rule is missing after its creation"
        }

        if ($Rule.Enabled -eq $false) {
            Change "Enabling HTTP rule"
            $Rule | Enable-NetFirewallRule -ErrorAction Stop
        }

        if (($Rule | Get-NetFirewallAddressFilter).RemoteAddress -ne "{{ int_net | ipaddr('network') }}/{{ int_net | ipaddr('netmask') }}") {
            Change "Changing HTTP rule remote address"
            $Rule | Set-NetFirewallRule -RemoteAddress "{{ int_net }}" -ErrorAction Stop
        }

        if ($Rule.Profile -ne "Domain,Private") {
            Change "Changing HTTP rule profile"
            $Rule | Set-NetFirewallRule -Profile Domain,Private -ErrorAction Stop
        }
    }
}



function Test-PSR {
    Debug "* Processing: PS Remoting Test"

    try {
        if ($Script:HasSSL) {
            Debug "Creating PS session through HTTPS"
            $Session = New-PSSession -UseSSL -ComputerName "localhost" -SessionOption (New-PSSessionOption -SkipRevocationCheck -SkipCNCheck) -Credential (New-Credential -User $ServiceUser -Password $ServicePassword)
        } else {
            Debug "Creating PS session through HTTP"
            $Session = New-PSSession -ComputerName "localhost" -Credential (New-Credential -User $ServiceUser -Password $ServicePassword)

        }
    } catch {
        Error "Caught an exception while setting up PS session: $_"
    }

    Assert $Session "Failed to initiate local PS Remoting session"
    Assert ((Invoke-Command -Session $Session -ScriptBlock {Write-Output "test"}) -eq "test") "Received wrong output from local PS remoting session"

    $Session | Remove-PSSession
}


Log "PS remoting preparation script" -Color Green
Log "Debug mode is $(("off","on")[$EnableDebug])"


Process-ServiceAccount -Name $ServiceUser -Password $ServicePassword
Process-NetworkProfile
Process-Registry

Process-WinRM
Process-PSRemoting
Process-Listeners
Process-SessionConfig
Process-PSRAuth
Process-Firewall

Process-WinRM

Test-PSR

Log "Completed" -Color Green