Is it possible to change NTFS permissions on a big tree faster?

Solution 1:

If you have SeRestorePrivilege, you can change the ACL of a file without having explicit access or being its owner. To take advantage of that fact, you can use PowerShell!

First, you'll need this gigantic script which I took from Lee Holmes with some tweaks to remove extra whitespace and allow multiple runs in one session:

param(    ## The privilege to adjust. This set is taken from
    ## http://msdn.microsoft.com/en-us/library/bb530716(VS.85).aspx
    [ValidateSet(
        "SeAssignPrimaryTokenPrivilege", "SeAuditPrivilege", "SeBackupPrivilege",
        "SeChangeNotifyPrivilege", "SeCreateGlobalPrivilege", "SeCreatePagefilePrivilege",
        "SeCreatePermanentPrivilege", "SeCreateSymbolicLinkPrivilege", "SeCreateTokenPrivilege",
        "SeDebugPrivilege", "SeEnableDelegationPrivilege", "SeImpersonatePrivilege", "SeIncreaseBasePriorityPrivilege",
        "SeIncreaseQuotaPrivilege", "SeIncreaseWorkingSetPrivilege", "SeLoadDriverPrivilege",
        "SeLockMemoryPrivilege", "SeMachineAccountPrivilege", "SeManageVolumePrivilege",
        "SeProfileSingleProcessPrivilege", "SeRelabelPrivilege", "SeRemoteShutdownPrivilege",
        "SeRestorePrivilege", "SeSecurityPrivilege", "SeShutdownPrivilege", "SeSyncAgentPrivilege",
        "SeSystemEnvironmentPrivilege", "SeSystemProfilePrivilege", "SeSystemtimePrivilege",
        "SeTakeOwnershipPrivilege", "SeTcbPrivilege", "SeTimeZonePrivilege", "SeTrustedCredManAccessPrivilege",
        "SeUndockPrivilege", "SeUnsolicitedInputPrivilege")]
    $Privilege,
    ## The process on which to adjust the privilege. Defaults to the current process.
    $ProcessId = $pid,
    ## Switch to disable the privilege, rather than enable it.
    [Switch] $Disable
)

## Taken from P/Invoke.NET with minor adjustments.
$definition = @'
using System;
using System.Runtime.InteropServices;
public class AdjPriv
{

    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
    internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall,
    ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen);

    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
    internal static extern bool OpenProcessToken(IntPtr h, int acc, ref IntPtr phtok);

    [DllImport("advapi32.dll", SetLastError = true)]
    internal static extern bool LookupPrivilegeValue(string host, string name, ref long pluid);

    [StructLayout(LayoutKind.Sequential, Pack = 1)]

    internal struct TokPriv1Luid
    {
        public int Count;
        public long Luid;
        public int Attr;
    }

    internal const int SE_PRIVILEGE_ENABLED = 0x00000002;
    internal const int SE_PRIVILEGE_DISABLED = 0x00000000;
    internal const int TOKEN_QUERY = 0x00000008;
    internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020;

    public static bool EnablePrivilege(long processHandle, string privilege, bool disable)
    {
        bool retVal;
        TokPriv1Luid tp;
        IntPtr hproc = new IntPtr(processHandle);
        IntPtr htok = IntPtr.Zero;
        retVal = OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, ref htok);
        tp.Count = 1;
        tp.Luid = 0;

        if(disable)
        {
            tp.Attr = SE_PRIVILEGE_DISABLED;
        }
        else
        {
            tp.Attr = SE_PRIVILEGE_ENABLED;
        }

        retVal = LookupPrivilegeValue(null, privilege, ref tp.Luid);
        retVal = AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero);
        return retVal;
    }
}

'@

$processHandle = (Get-Process -id $ProcessId).Handle
try { 
  Add-Type $definition 
} catch {} # Silent failure on re-registration

[AdjPriv]::EnablePrivilege($processHandle, $Privilege, $Disable)

Save it as a .ps1 file, adjpriv.ps1 for example. To allow PowerShell scripts to run, see the Enabling Scripts section of the PowerShell tag wiki.

Now you can use this little script to recursively allow Administrators full control of everything in the current directory:

.\adjpriv.ps1 SeRestorePrivilege
Get-ChildItem -Recurse -Force | % {
    $acl = Get-Acl $_
    $rule = New-Object System.Security.AccessControl.FileSystemAccessRule ('Administrators', 'FullControl', 'Allow')
    $acl.AddAccessRule($rule)
    Set-Acl $_ $acl
}

The ACLs are each updated, but the owner isn't changed, saving you the time it would take to do that first.

If you need to control how the new access rule applies to new items in existing directories, you can adjust the script to use this other constructor of FileSystemAccessRule.