Following the provided link through to the code at http://www.hightechtalks.com/csharp/lsa-functions-276626.html
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;
}
lts (an LSA_TRANSLATED_SID2 struct) contains a pointer that points at memory that is freed by the call to Win32Sec.LsaFreeMemory. Using the pointer after the memory is freed is bad practice and will have unpredictable results -- it might even "work".
Tweaking the code at the link by using the SecurityIdentifier class (.Net 2 and above) along a little cleanup of unneeded code avoids the memory problem.
using System;
namespace Willys.LsaSecurity
{
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Principal;
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")]
internal static extern int LsaNtStatusToWinError(int NTSTATUS);
[DllImport("advapi32")]
internal static extern int LsaClose(IntPtr PolicyHandle);
}
sealed class Sid : IDisposable
{
public IntPtr pSid = IntPtr.Zero;
public SecurityIdentifier sid = null;
public Sid(string account)
{
sid = (SecurityIdentifier) (new NTAccount(account)).Translate(typeof(SecurityIdentifier));
Byte[] buffer = new Byte[sid.BinaryLength];
sid.GetBinaryForm(buffer, 0);
pSid = Marshal.AllocHGlobal(sid.BinaryLength);
Marshal.Copy(buffer, 0, pSid, sid.BinaryLength);
}
public void Dispose()
{
if (pSid != IntPtr.Zero)
{
Marshal.FreeHGlobal(pSid);
pSid = IntPtr.Zero;
}
GC.SuppressFinalize(this);
}
~Sid()
{
Dispose();
}
}
public sealed class LsaWrapper : IDisposable
{
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)
{
uint ret = 0;
using (Sid sid = new Sid(account))
{
LSA_UNICODE_STRING[] privileges = new LSA_UNICODE_STRING[1];
privileges[0] = InitLsaString(privilege);
ret = Win32Sec.LsaAddAccountRights(lsaHandle, sid.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
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;
}
}
}
Win32Sec.LsaFreeMemorydid catch my eye. Although, I figured "whomever wrote this probably knows best". – Bennybenoit