SpeculationControl.psm1

function Get-SpeculationControlSettings {
  <#

  .SYNOPSIS
  This function queries the speculation control settings for the system.

  .DESCRIPTION
  This function queries the speculation control settings for the system.

  Version 1.3.
  
  #>

  [CmdletBinding()]
  param (

  )
  
  process {

    $NtQSIDefinition = @'
    [DllImport("ntdll.dll")]
    public static extern int NtQuerySystemInformation(uint systemInformationClass, IntPtr systemInformation, uint systemInformationLength, IntPtr returnLength);
'@
    
    $ntdll = Add-Type -MemberDefinition $NtQSIDefinition -Name 'ntdll' -Namespace 'Win32' -PassThru


    [System.IntPtr]$systemInformationPtr = [System.Runtime.InteropServices.Marshal]::AllocHGlobal(4)
    [System.IntPtr]$returnLengthPtr = [System.Runtime.InteropServices.Marshal]::AllocHGlobal(4)

    $object = New-Object -TypeName PSObject

    try {
    
        #
        # Query branch target injection information.
        #

        Write-Host "Speculation control settings for CVE-2017-5715 [branch target injection]" -ForegroundColor Cyan
        Write-Host

        $btiHardwarePresent = $false
        $btiWindowsSupportPresent = $false
        $btiWindowsSupportEnabled = $false
        $btiDisabledBySystemPolicy = $false
        $btiDisabledByNoHardwareSupport = $false
    
        [System.UInt32]$systemInformationClass = 201
        [System.UInt32]$systemInformationLength = 4

        $retval = $ntdll::NtQuerySystemInformation($systemInformationClass, $systemInformationPtr, $systemInformationLength, $returnLengthPtr)

        if ($retval -eq 0xc0000003 -or $retval -eq 0xc0000002) {
            # fallthrough
        }
        elseif ($retval -ne 0) {
            throw (("Querying branch target injection information failed with error {0:X8}" -f $retval))
        }
        else {
    
            [System.UInt32]$scfBpbEnabled = 0x01
            [System.UInt32]$scfBpbDisabledSystemPolicy = 0x02
            [System.UInt32]$scfBpbDisabledNoHardwareSupport = 0x04
            [System.UInt32]$scfHwReg1Enumerated = 0x08
            [System.UInt32]$scfHwReg2Enumerated = 0x10
            [System.UInt32]$scfHwMode1Present = 0x20
            [System.UInt32]$scfHwMode2Present = 0x40
            [System.UInt32]$scfSmepPresent = 0x80

            [System.UInt32]$flags = [System.UInt32][System.Runtime.InteropServices.Marshal]::ReadInt32($systemInformationPtr)

            $btiHardwarePresent = ((($flags -band $scfHwReg1Enumerated) -ne 0) -or (($flags -band $scfHwReg2Enumerated)))
            $btiWindowsSupportPresent = $true
            $btiWindowsSupportEnabled = (($flags -band $scfBpbEnabled) -ne 0)

            if ($btiWindowsSupportEnabled -eq $false) {
                $btiDisabledBySystemPolicy = (($flags -band $scfBpbDisabledSystemPolicy) -ne 0)
                $btiDisabledByNoHardwareSupport = (($flags -band $scfBpbDisabledNoHardwareSupport) -ne 0)
            }

            if ($PSBoundParameters['Verbose']) {
                Write-Host "BpbEnabled                   :" (($flags -band $scfBpbEnabled) -ne 0)
                Write-Host "BpbDisabledSystemPolicy      :" (($flags -band $scfBpbDisabledSystemPolicy) -ne 0)
                Write-Host "BpbDisabledNoHardwareSupport :" (($flags -band $scfBpbDisabledNoHardwareSupport) -ne 0)
                Write-Host "HwReg1Enumerated             :" (($flags -band $scfHwReg1Enumerated) -ne 0)
                Write-Host "HwReg2Enumerated             :" (($flags -band $scfHwReg2Enumerated) -ne 0)
                Write-Host "HwMode1Present               :" (($flags -band $scfHwMode1Present) -ne 0)
                Write-Host "HwMode2Present               :" (($flags -band $scfHwMode2Present) -ne 0)
                Write-Host "SmepPresent                  :" (($flags -band $scfSmepPresent) -ne 0)
            }
        }

        Write-Host "Hardware support for branch target injection mitigation is present:"($btiHardwarePresent) -ForegroundColor $(If ($btiHardwarePresent) { [System.ConsoleColor]::Green } Else { [System.ConsoleColor]::Red })
        Write-Host "Windows OS support for branch target injection mitigation is present:"($btiWindowsSupportPresent) -ForegroundColor $(If ($btiWindowsSupportPresent) { [System.ConsoleColor]::Green } Else { [System.ConsoleColor]::Red })
        Write-Host "Windows OS support for branch target injection mitigation is enabled:"($btiWindowsSupportEnabled) -ForegroundColor $(If ($btiWindowsSupportEnabled) { [System.ConsoleColor]::Green } Else { [System.ConsoleColor]::Red })
  
        if ($btiWindowsSupportPresent -eq $true -and $btiWindowsSupportEnabled -eq $false) {
            Write-Host -ForegroundColor Red "Windows OS support for branch target injection mitigation is disabled by system policy:"($btiDisabledBySystemPolicy)
            Write-Host -ForegroundColor Red "Windows OS support for branch target injection mitigation is disabled by absence of hardware support:"($btiDisabledByNoHardwareSupport)
        }
        
        $object | Add-Member -MemberType NoteProperty -Name BTIHardwarePresent -Value $btiHardwarePresent
        $object | Add-Member -MemberType NoteProperty -Name BTIWindowsSupportPresent -Value $btiWindowsSupportPresent
        $object | Add-Member -MemberType NoteProperty -Name BTIWindowsSupportEnabled -Value $btiWindowsSupportEnabled
        $object | Add-Member -MemberType NoteProperty -Name BTIDisabledBySystemPolicy -Value $btiDisabledBySystemPolicy
        $object | Add-Member -MemberType NoteProperty -Name BTIDisabledByNoHardwareSupport -Value $btiDisabledByNoHardwareSupport

        #
        # Query kernel VA shadow information.
        #

        Write-Host
        Write-Host "Speculation control settings for CVE-2017-5754 [rogue data cache load]" -ForegroundColor Cyan
        Write-Host    

        $kvaShadowRequired = $true
        $kvaShadowPresent = $false
        $kvaShadowEnabled = $false
        $kvaShadowPcidEnabled = $false

        $cpu = Get-WmiObject Win32_Processor

        if ($cpu.Manufacturer -eq "AuthenticAMD") {
            $kvaShadowRequired = $false
        }
        elseif ($cpu.Manufacturer -eq "GenuineIntel") {
            $regex = [regex]'Family (\d+) Model (\d+) Stepping (\d+)'
            $result = $regex.Match($cpu.Description)
            
            if ($result.Success) {
                $family = [System.UInt32]$result.Groups[1].Value
                $model = [System.UInt32]$result.Groups[2].Value
                $stepping = [System.UInt32]$result.Groups[3].Value
                
                if (($family -eq 0x6) -and 
                    (($model -eq 0x1c) -or
                     ($model -eq 0x26) -or
                     ($model -eq 0x27) -or
                     ($model -eq 0x36) -or
                     ($model -eq 0x35))) {

                    $kvaShadowRequired = $false
                }
            }
        }
        else {
            throw ("Unsupported processor manufacturer: {0}" -f $cpu.Manufacturer)
        }

        [System.UInt32]$systemInformationClass = 196
        [System.UInt32]$systemInformationLength = 4

        $retval = $ntdll::NtQuerySystemInformation($systemInformationClass, $systemInformationPtr, $systemInformationLength, $returnLengthPtr)

        if ($retval -eq 0xc0000003 -or $retval -eq 0xc0000002) {
        }
        elseif ($retval -ne 0) {
            throw (("Querying kernel VA shadow information failed with error {0:X8}" -f $retval))
        }
        else {
    
            [System.UInt32]$kvaShadowEnabledFlag = 0x01
            [System.UInt32]$kvaShadowUserGlobalFlag = 0x02
            [System.UInt32]$kvaShadowPcidFlag = 0x04
            [System.UInt32]$kvaShadowInvpcidFlag = 0x08

            [System.UInt32]$flags = [System.UInt32][System.Runtime.InteropServices.Marshal]::ReadInt32($systemInformationPtr)

            $kvaShadowPresent = $true
            $kvaShadowEnabled = (($flags -band $kvaShadowEnabledFlag) -ne 0)
            $kvaShadowPcidEnabled = ((($flags -band $kvaShadowPcidFlag) -ne 0) -and (($flags -band $kvaShadowInvpcidFlag) -ne 0))

            if ($PSBoundParameters['Verbose']) {
                Write-Host "KvaShadowEnabled             :" (($flags -band $kvaShadowEnabledFlag) -ne 0)
                Write-Host "KvaShadowUserGlobal          :" (($flags -band $kvaShadowUserGlobalFlag) -ne 0)
                Write-Host "KvaShadowPcid                :" (($flags -band $kvaShadowPcidFlag) -ne 0)
                Write-Host "KvaShadowInvpcid             :" (($flags -band $kvaShadowInvpcidFlag) -ne 0)
            }
        }
        
        Write-Host "Hardware requires kernel VA shadowing:"$kvaShadowRequired

        if ($kvaShadowRequired) {

            Write-Host "Windows OS support for kernel VA shadow is present:"$kvaShadowPresent -ForegroundColor $(If ($kvaShadowPresent) { [System.ConsoleColor]::Green } Else { [System.ConsoleColor]::Red })
            Write-Host "Windows OS support for kernel VA shadow is enabled:"$kvaShadowEnabled -ForegroundColor $(If ($kvaShadowEnabled) { [System.ConsoleColor]::Green } Else { [System.ConsoleColor]::Red })

            if ($kvaShadowEnabled) {
                Write-Host "Windows OS support for PCID optimization is enabled:"$kvaShadowPcidEnabled -ForegroundColor $(If ($kvaShadowPcidEnabled) { [System.ConsoleColor]::Green } Else { [System.ConsoleColor]::Red })
            }
        }

        
        $object | Add-Member -MemberType NoteProperty -Name KVAShadowRequired -Value $kvaShadowRequired
        $object | Add-Member -MemberType NoteProperty -Name KVAShadowWindowsSupportPresent -Value $kvaShadowPresent
        $object | Add-Member -MemberType NoteProperty -Name KVAShadowWindowsSupportEnabled -Value $kvaShadowEnabled
        $object | Add-Member -MemberType NoteProperty -Name KVAShadowPcidEnabled -Value $kvaShadowPcidEnabled

        #
        # Provide guidance as appropriate.
        #

        $actions = @()
        
        if ($btiHardwarePresent -eq $false) {
            $actions += "Install BIOS/firmware update provided by your device OEM that enables hardware support for the branch target injection mitigation."
        }

        if ($btiWindowsSupportPresent -eq $false -or $kvaShadowPresent -eq $false) {
            $actions += "Install the latest available updates for Windows with support for speculation control mitigations."
        }

        if ($btiWindowsSupportEnabled -eq $false -or ($kvaShadowRequired -eq $true -and $kvaShadowEnabled -eq $false)) {
            $actions += "Follow the guidance for enabling Windows support for speculation control mitigations are described in https://support.microsoft.com/help/4072698"
        }

        if ($actions.Length -gt 0) {

            Write-Host
            Write-Host "Suggested actions" -ForegroundColor Cyan
            Write-Host 

            foreach ($action in $actions) {
                Write-Host " *" $action
            }
        }


        return $object

    }
    finally
    {
        if ($systemInformationPtr -ne [System.IntPtr]::Zero) {
            [System.Runtime.InteropServices.Marshal]::FreeHGlobal($systemInformationPtr)
        }
 
        if ($returnLengthPtr -ne [System.IntPtr]::Zero) {
            [System.Runtime.InteropServices.Marshal]::FreeHGlobal($returnLengthPtr)
        }
    }    
  }
}