Morten said:
Hi!
Has anyone been able to use LSA functions to grant or remove privileges
to/from users? I'm trying to find a way to programmatically set the "Deny
logon through Terminal Services" privilege for certain users. If someone
has a small example of how to use these functions from C# it would be very
helpful.
Thanks in advance
Morten
Here a simple class that should do the job (use at own risk). Note that IMO,
this kind of PInvoke stuff could better be done using MC++ (C++/CLI) or
using System.Management (WMI) and RSOP.
namespace Willys.LsaSecurity
{
using System.Runtime.InteropServices;
using System.Security;
using System.Management;
using System.Runtime.CompilerServices;
using System.ComponentModel;
using LSA_HANDLE = IntPtr;
[StructLayout(LayoutKind.Sequential)]
struct LSA_OBJECT_ATTRIBUTES {
internal int Length;
internal IntPtr RootDirectory;
internal IntPtr ObjectName;
internal int Attributes;
internal IntPtr SecurityDescriptor;
internal IntPtr SecurityQualityOfService;
}
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
struct LSA_UNICODE_STRING
{
internal ushort Length;
internal ushort MaximumLength;
[MarshalAs(UnmanagedType.LPWStr)]
internal string Buffer;
}
sealed class Win32Sec
{
[DllImport("advapi32", CharSet=CharSet.Unicode, SetLastError=true),
SuppressUnmanagedCodeSecurityAttribute]
internal static extern uint LsaOpenPolicy(
LSA_UNICODE_STRING[] SystemName,
ref LSA_OBJECT_ATTRIBUTES ObjectAttributes,
int AccessMask,
out IntPtr PolicyHandle
);
[DllImport("advapi32", CharSet=CharSet.Unicode, SetLastError=true),
SuppressUnmanagedCodeSecurityAttribute]
internal static extern uint LsaAddAccountRights(
LSA_HANDLE PolicyHandle,
IntPtr pSID,
LSA_UNICODE_STRING[] UserRights,
int CountOfRights
);
[DllImport("advapi32", CharSet=CharSet.Unicode, SetLastError=true),
SuppressUnmanagedCodeSecurityAttribute]
internal static extern int LsaLookupNames2(
LSA_HANDLE PolicyHandle,
uint Flags,
uint Count,
LSA_UNICODE_STRING[] Names,
ref IntPtr ReferencedDomains,
ref IntPtr Sids
);
[DllImport("advapi32")]
internal static extern int LsaNtStatusToWinError(int NTSTATUS);
[DllImport("advapi32")]
internal static extern int LsaClose(IntPtr PolicyHandle);
[DllImport("advapi32")]
internal static extern int LsaFreeMemory(IntPtr Buffer);
}
public sealed class LsaWrapper : IDisposable
{
[StructLayout(LayoutKind.Sequential)]
struct LSA_TRUST_INFORMATION {
internal LSA_UNICODE_STRING Name;
internal IntPtr Sid;
}
[StructLayout(LayoutKind.Sequential)]
struct LSA_TRANSLATED_SID2 {
internal SidNameUse Use;
internal IntPtr Sid;
internal int DomainIndex;
uint Flags;
}
[StructLayout(LayoutKind.Sequential)]
struct LSA_REFERENCED_DOMAIN_LIST {
internal uint Entries;
internal LSA_TRUST_INFORMATION Domains;
}
enum SidNameUse : int {
User = 1,
Group = 2,
Domain = 3,
Alias = 4,
KnownGroup = 5,
DeletedAccount = 6,
Invalid = 7,
Unknown = 8,
Computer = 9
}
enum Access : int {
POLICY_READ = 0x20006,
POLICY_ALL_ACCESS = 0x00F0FFF,
POLICY_EXECUTE = 0X20801,
POLICY_WRITE = 0X207F8
}
const uint STATUS_ACCESS_DENIED = 0xc0000022;
const uint STATUS_INSUFFICIENT_RESOURCES = 0xc000009a;
const uint STATUS_NO_MEMORY = 0xc0000017;
IntPtr lsaHandle;
public LsaWrapper(): this (null)
{}
// // local system if systemName is null
public LsaWrapper(string systemName)
{
LSA_OBJECT_ATTRIBUTES lsaAttr;
lsaAttr.RootDirectory = IntPtr.Zero;
lsaAttr.ObjectName = IntPtr.Zero;
lsaAttr.Attributes = 0;
lsaAttr.SecurityDescriptor = IntPtr.Zero;
lsaAttr.SecurityQualityOfService = IntPtr.Zero;
lsaAttr.Length = Marshal.SizeOf(typeof(LSA_OBJECT_ATTRIBUTES));
lsaHandle = IntPtr.Zero;
LSA_UNICODE_STRING[] system = null;
if (systemName != null)
{
system = new LSA_UNICODE_STRING[1];
system[0] = InitLsaString(systemName);
}
uint ret = Win32Sec.LsaOpenPolicy(system, ref lsaAttr,
(int)Access.POLICY_ALL_ACCESS, out lsaHandle);
if (ret == 0)
return;
if (ret == STATUS_ACCESS_DENIED)
{
throw new UnauthorizedAccessException();
}
if ((ret == STATUS_INSUFFICIENT_RESOURCES) || (ret == STATUS_NO_MEMORY))
{
throw new OutOfMemoryException();
}
throw new Win32Exception(Win32Sec.LsaNtStatusToWinError((int)ret));
}
public void AddPrivileges(string account, string privilege)
{
IntPtr pSid = GetSIDInformation(account);
LSA_UNICODE_STRING[] privileges = new LSA_UNICODE_STRING[1];
privileges[0] = InitLsaString(privilege);
uint ret = Win32Sec.LsaAddAccountRights(lsaHandle, pSid, privileges, 1);
if (ret == 0)
return;
if (ret == STATUS_ACCESS_DENIED)
{
throw new UnauthorizedAccessException();
}
if ((ret == STATUS_INSUFFICIENT_RESOURCES) || (ret == STATUS_NO_MEMORY))
{
throw new OutOfMemoryException();
}
throw new Win32Exception(Win32Sec.LsaNtStatusToWinError((int)ret));
}
public void Dispose() {
if (lsaHandle != IntPtr.Zero)
{
Win32Sec.LsaClose(lsaHandle);
lsaHandle = IntPtr.Zero;
}
GC.SuppressFinalize(this);
}
~LsaWrapper()
{
Dispose();
}
// helper functions
IntPtr GetSIDInformation(string account)
{
LSA_UNICODE_STRING[] names = new LSA_UNICODE_STRING[1];
LSA_TRANSLATED_SID2 lts;
IntPtr tsids = IntPtr.Zero;
IntPtr tdom = IntPtr.Zero;
names[0] = InitLsaString(account);
lts.Sid = IntPtr.Zero;
Console.WriteLine("String account: {0}", names[0].Length);
int ret = Win32Sec.LsaLookupNames2(lsaHandle, 0, 1, names, ref tdom, ref
tsids);
if (ret != 0)
throw new Win32Exception(Win32Sec.LsaNtStatusToWinError(ret));
lts = (LSA_TRANSLATED_SID2)Marshal.PtrToStructure(tsids,
typeof(LSA_TRANSLATED_SID2));
Win32Sec.LsaFreeMemory(tsids);
Win32Sec.LsaFreeMemory(tdom);
return lts.Sid;
}
static LSA_UNICODE_STRING InitLsaString(string s)
{
// Unicode strings max. 32KB
if (s.Length > 0x7ffe)
throw new ArgumentException("String too long");
LSA_UNICODE_STRING lus = new LSA_UNICODE_STRING();
lus.Buffer = s;
lus.Length = (ushort)(s.Length * sizeof(char));
lus.MaximumLength = (ushort)(lus.Length + sizeof(char));
return lus;
}
}
}
// usage....
using (Willys.LsaSecurity.LsaWrapper lsa = new
Willys.LsaSecurity.LsaWrapper())
{
// add SeDenyRemoteInteractiveLogonRight will effectively deny TS access to
someAccount
lsa.AddPrivileges("someAccount",
"SeDenyRemoteInteractiveLogonRight");
}
Willy.
