Added WinRM elevated shell wrapper script

This script creates an immediately run scheduled task using fresh credentials. This is a generic implementation used by the Chef provisioners. The script gets around several limitations in WinRM.

1. Credential hopping
2. The non-default Administrator account sometimes doesn't have true Administrator access when run through WinRM even with UAC disabled.

In short, this script allows commands to run through WinRM just as if they were run directly on the box.

plugins/communicators/winrm/scripts/elevated_shell.ps1.erb

@@ -0,0 +1,95 @@
+$command = "<%= options[:command] %>"
+$user = "<%= options[:username] %>"
+$password = "<%= options[:password] %>"
+
+$task_name = "WinRM_Elevated_Shell"
+$out_file = "$env:SystemRoot\Temp\WinRM_Elevated_Shell.log"
+
+if (Test-Path $out_file) {
+  del $out_file
+}
+
+$task_xml = @'
+<?xml version="1.0" encoding="UTF-16"?>
+<Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
+  <Principals>
+    <Principal id="Author">
+      <UserId>{user}</UserId>
+      <LogonType>Password</LogonType>
+      <RunLevel>HighestAvailable</RunLevel>
+    </Principal>
+  </Principals>
+  <Settings>
+    <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
+    <DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries>
+    <StopIfGoingOnBatteries>false</StopIfGoingOnBatteries>
+    <AllowHardTerminate>true</AllowHardTerminate>
+    <StartWhenAvailable>false</StartWhenAvailable>
+    <RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
+    <IdleSettings>
+      <StopOnIdleEnd>true</StopOnIdleEnd>
+      <RestartOnIdle>false</RestartOnIdle>
+    </IdleSettings>
+    <AllowStartOnDemand>true</AllowStartOnDemand>
+    <Enabled>true</Enabled>
+    <Hidden>false</Hidden>
+    <RunOnlyIfIdle>false</RunOnlyIfIdle>
+    <WakeToRun>false</WakeToRun>
+    <ExecutionTimeLimit>PT2H</ExecutionTimeLimit>
+    <Priority>4</Priority>
+  </Settings>
+  <Actions Context="Author">
+    <Exec>
+      <Command>cmd</Command>
+      <Arguments>{arguments}</Arguments>
+    </Exec>
+  </Actions>
+</Task>
+'@
+
+$bytes = [System.Text.Encoding]::Unicode.GetBytes($command)
+$encoded_command = [Convert]::ToBase64String($bytes)
+$arguments = "/c powershell.exe -EncodedCommand $encoded_command &gt; $out_file 2&gt;&amp;1"
+
+$task_xml = $task_xml.Replace("{arguments}", $arguments)
+$task_xml = $task_xml.Replace("{user}", $user)
+
+$schedule = New-Object -ComObject "Schedule.Service"
+$schedule.Connect()
+$task = $schedule.NewTask($null)
+$task.XmlText = $task_xml
+$folder = $schedule.GetFolder("\")
+$folder.RegisterTaskDefinition($task_name, $task, 6, $user, $password, 1, $null) | Out-Null
+
+$registered_task = $folder.GetTask("\$task_name")
+$registered_task.Run($null) | Out-Null
+
+$timeout = 10
+$sec = 0
+while ( (!($registered_task.state -eq 4)) -and ($sec -lt $timeout) ) {
+  Start-Sleep -s 1
+  $sec++
+}
+
+# Read the entire file, but only write out new lines we haven't seen before
+$numLinesRead = 0
+do {
+  Start-Sleep -m 100
+  
+  if (Test-Path $out_file) {
+    $text = (get-content $out_file)
+    $numLines = ($text | Measure-Object -line).lines    
+    $numLinesToRead = $numLines - $numLinesRead
+    
+    if ($numLinesToRead -gt 0) {
+      $text | select -first $numLinesToRead -skip $numLinesRead | ForEach {
+        Write-Host "$_"
+      }
+      $numLinesRead += $numLinesToRead
+    }
+  }
+} while (!($registered_task.state -eq 3))
+
+$exit_code = $registered_task.LastTaskResult
+[System.Runtime.Interopservices.Marshal]::ReleaseComObject($schedule) | Out-Null
+exit $exit_code