How does one retrieve the Windows Logon SID in C# .net? (not the user SID, but the unique new one for each session)
I'm afraid you have to resort to using P/Invoke. There's an example how to do it at pinvoke.net (please see the bottom of the page):
Result = GetTokenInformation(WindowsIdentity.GetCurrent().Token, TOKEN_INFORMATION_CLASS.TokenSessionId , TokenInformation , TokenInfLength , out TokenInfLength );
Please note that I changed the example by altering just one line, I replaced TOKEN_INFORMATION_CLASS.TokenUser
with TOKEN_INFORMATION_CLASS.TokenSessionId
which is exactly what you need.
Hope this helps.
Update: Here's the working (at least on my machine) code:
using System;
using System.Runtime.InteropServices;
using System.Security.Principal;
namespace LinqTest
{
public class ClsLookupAccountName
{
public const uint SE_GROUP_LOGON_ID = 0xC0000000; // from winnt.h
public const int TokenGroups = 2; // from TOKEN_INFORMATION_CLASS
enum TOKEN_INFORMATION_CLASS
{
TokenUser = 1,
TokenGroups,
TokenPrivileges,
TokenOwner,
TokenPrimaryGroup,
TokenDefaultDacl,
TokenSource,
TokenType,
TokenImpersonationLevel,
TokenStatistics,
TokenRestrictedSids,
TokenSessionId,
TokenGroupsAndPrivileges,
TokenSessionReference,
TokenSandBoxInert,
TokenAuditPolicy,
TokenOrigin
}
[StructLayout(LayoutKind.Sequential)]
public struct SID_AND_ATTRIBUTES
{
public IntPtr Sid;
public uint Attributes;
}
[StructLayout(LayoutKind.Sequential)]
public struct TOKEN_GROUPS
{
public int GroupCount;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)]
public SID_AND_ATTRIBUTES[] Groups;
};
// Using IntPtr for pSID instead of Byte[]
[DllImport("advapi32", CharSet = CharSet.Auto, SetLastError = true)]
static extern bool ConvertSidToStringSid(IntPtr pSID, out IntPtr ptrSid);
[DllImport("kernel32.dll")]
static extern IntPtr LocalFree(IntPtr hMem);
[DllImport("advapi32.dll", SetLastError = true)]
static extern bool GetTokenInformation(
IntPtr TokenHandle,
TOKEN_INFORMATION_CLASS TokenInformationClass,
IntPtr TokenInformation,
int TokenInformationLength,
out int ReturnLength);
public static string GetLogonId()
{
int TokenInfLength = 0;
// first call gets lenght of TokenInformation
bool Result = GetTokenInformation(WindowsIdentity.GetCurrent().Token, TOKEN_INFORMATION_CLASS.TokenGroups, IntPtr.Zero, TokenInfLength, out TokenInfLength);
IntPtr TokenInformation = Marshal.AllocHGlobal(TokenInfLength);
Result = GetTokenInformation(WindowsIdentity.GetCurrent().Token, TOKEN_INFORMATION_CLASS.TokenGroups, TokenInformation, TokenInfLength, out TokenInfLength);
if (!Result)
{
Marshal.FreeHGlobal(TokenInformation);
return string.Empty;
}
string retVal = string.Empty;
TOKEN_GROUPS groups = (TOKEN_GROUPS)Marshal.PtrToStructure(TokenInformation, typeof(TOKEN_GROUPS));
int sidAndAttrSize = Marshal.SizeOf(new SID_AND_ATTRIBUTES());
for (int i = 0; i < groups.GroupCount; i++)
{
SID_AND_ATTRIBUTES sidAndAttributes = (SID_AND_ATTRIBUTES)Marshal.PtrToStructure(
new IntPtr(TokenInformation.ToInt64() + i * sidAndAttrSize + IntPtr.Size), typeof(SID_AND_ATTRIBUTES));
if ((sidAndAttributes.Attributes & SE_GROUP_LOGON_ID) == SE_GROUP_LOGON_ID)
{
IntPtr pstr = IntPtr.Zero;
ConvertSidToStringSid(sidAndAttributes.Sid, out pstr);
retVal = Marshal.PtrToStringAuto(pstr);
LocalFree(pstr);
break;
}
}
Marshal.FreeHGlobal(TokenInformation);
return retVal;
}
}
}
N.B. I tested it on my x64 machine, so please pay close attention on TokenInformation.ToInt64()
piece of code, maybe you should replace it with TokenInformation.ToInt32()