Develop Reference

MemoryMappedFileSecurity missing in .NET 6

I have a service that makes use of MemoryMappedFiles for interprocess communication. It has worked great for many years and was developed in .NET Framework 4.6.1. Now comes the time to port the code to .NET 6. I've gotten the bulk of it to work correctly except for one issue: the security ACL for the memory mapped file. That argument seems to have disappeared in .NET 6.
Here is a snippet from the 4.6.1 Framework version
fs = new FileStream(FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
FileSecurity fSec = File.GetAccessControl(FileName);
fSec.AddAccessRule(new FileSystemAccessRule("everyone", FileSystemRights.FullControl, AccessControlType.Allow));
File.SetAccessControl(FileName, fSec);
if (fs.Length == 0)
fs.SetLength(_SectionSize);
long fLen = fs.Length;
MemoryMappedFileSecurity security = new MemoryMappedFileSecurity();
security.AddAccessRule(new AccessRule<MemoryMappedFileRights>("everyone", MemoryMappedFileRights.FullControl, AccessControlType.Allow));
//Name = #"Global\DCCCache"; // "Global\" when running as a service so session 0 stuff available to everyone
_MMFHandle = MemoryMappedFile.CreateFromFile(fs, Name, _SectionSize, MemoryMappedFileAccess.ReadWrite, security, HandleInheritability.Inheritable, false);
_VAHandle = _MMFHandle.CreateViewAccessor();
This all works and allows non-admin user processes access to the memory mapped file.
.NET 6 drops the security argument from the .CreateFromFile method. As a result, only processes running with Administrator privileges have access to the memory mapped file. An "Access Denied" IO exception is thrown from the OpenExisting method of MemoryMappedFile for non-admin processes.
Is there a way to modify the security when I create a memory mapped file so non-admin processes have access?

I did a workaround. Put together the call I needed to create the memory mapped file with the correct security and call it once in the service that owns it. I changed the mainline code to use OpenExisting after the call to the routine below so the remainder of the code can use the .NET 6 library as intended. Not ideal, but it fixed the issue.
using System.ComponentModel;
using System.Runtime.InteropServices;
using Microsoft.Win32.SafeHandles;
namespace MMFService {
internal class MMFNet6Shim : IDisposable {
private bool win32Result = false;
private int cbSid = SECURITY_MAX_SID_SIZE;
private SECURITY_ATTRIBUTES securityAttributes = new SECURITY_ATTRIBUTES();
private SafeMemoryMappedFileHandle hFile;
private const int SDDL_REVISION_1 = 1;
private const int SECURITY_MAX_SID_SIZE = 68;
private const int PAGE_READWRITE = 0x04;
private const int FILE_MAP_WRITE = 0X02;
public MMFNet6Shim(FileStream fs, string DBName) {
win32Result = ConvertStringSecurityDescriptorToSecurityDescriptor("D:(A;OICI;GA;;;WD)", SDDL_REVISION_1, out securityAttributes.lpSecurityDescriptor, IntPtr.Zero);
if (!win32Result)
throw new Exception("ConvertStringSecurityDescriptorToSecurityDescriptor", new Win32Exception(Marshal.GetLastWin32Error()));
securityAttributes.nLength = Marshal.SizeOf(securityAttributes);
securityAttributes.bInheritHandle = false;
long fLen = fs.Length;
hFile = CreateFileMapping(fs.SafeFileHandle, ref securityAttributes, PAGE_READWRITE, 0, Convert.ToInt32(fLen), DBName);
if (hFile.IsInvalid)
throw new Exception("CreateFileMapping", new Win32Exception(Marshal.GetLastWin32Error()));
}
public void Dispose() {
if(!hFile.IsInvalid)
hFile.Close();
}
[StructLayout(LayoutKind.Sequential)]
public struct SECURITY_ATTRIBUTES {
public int nLength;
public IntPtr lpSecurityDescriptor;
public bool bInheritHandle;
}
[DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern bool ConvertStringSecurityDescriptorToSecurityDescriptor
(
[In] string StringSecurityDescriptor,
[In] int StringSDRevision,
[Out] out IntPtr SecurityDescriptor,
[Out] IntPtr SecurityDescriptorSize
);
[DllImport("kernel32.dll", SetLastError = true)]
public static extern IntPtr LocalFree([In] IntPtr hMem);
[DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern SafeMemoryMappedFileHandle CreateFileMapping(
[In] SafeFileHandle hFile,
[In][Optional] ref SECURITY_ATTRIBUTES lpAttributes,
[In] int flProtect,
[In] int dwMaximumSizeHigh,
[In] int dwMaximumSizeLow,
[In][Optional] string lpName
);
}
}

The easiest way is to set access for Everyone:
using System.Runtime.InteropServices;
[DllImport("advapi32.dll", EntryPoint = "SetSecurityInfo", CallingConvention = CallingConvention.Winapi,
SetLastError = true, ExactSpelling = true, CharSet = CharSet.Unicode)]
private static extern uint SetSecurityInfoByHandle(SafeHandle handle, uint objectType, uint securityInformation,
byte[]? owner, byte[]? group, byte[]? dacl, byte[]? sacl);
then
mmfile = MemoryMappedFile.CreateNew("Global\\jdfghdfghsd", requiredsize, MemoryMappedFileAccess.ReadWrite);
if (SetSecurityInfoByHandle(mmfile.SafeMemoryMappedFileHandle, 1, 4, null, null, null, null) != 0)
throw new Exception("MemoryMappedFile set security failed");
Set customized access rights if required, look at SetSecurityInfo help
So, sample apps:
App1:
using System.IO.MemoryMappedFiles;
using System.Runtime.InteropServices;
[DllImport("advapi32.dll", EntryPoint = "SetSecurityInfo", CallingConvention = CallingConvention.Winapi,
SetLastError = true, ExactSpelling = true, CharSet = CharSet.Unicode)]
static extern uint SetSecurityInfoByHandle(SafeHandle handle, uint objectType, uint securityInformation,
byte[]? owner, byte[]? group, byte[]? dacl, byte[]? sacl);
var mmfile = MemoryMappedFile.CreateNew("Global\\dsfgsdfsdf", 4, MemoryMappedFileAccess.ReadWrite);
if (SetSecurityInfoByHandle(mmfile.SafeMemoryMappedFileHandle, 1, 4, null, null, null, null) != 0)
throw new Exception("Access rights set up failed");
mmfile.CreateViewAccessor(0, 4).Write(0, 234);
Console.ReadLine();
App2:
using System.IO.MemoryMappedFiles;
Console.WriteLine(MemoryMappedFile.OpenExisting("Global\\dsfgsdfsdf", MemoryMappedFileRights.ReadWrite).CreateViewAccessor(0, 4).ReadInt32(0));
Console.ReadLine();
Run app1, then app2. It should emit 234. Then press Enter for app1.
Be sure the user runs app1 is able to create the global objects (by default only administrators and services are allowed)

Copy file using impersonation and CopyFileEx from Kernel DLL?

I am using the following code to copy a file to a directory where only one X user has access, I am using impersonation but when I use it the CopyFileEx does not work, but I don't know why. if I remove the part of the impersonation it works correctly but I need it to be copied with a user X since in production it has to be like that.
ImpersonationUtils impersonation = new ImpersonationUtils();
var token = impersonation.LogonAsUser("User", "Domain", "pwd");
if (!IntPtr.Equals(token, IntPtr.Zero))
{
System.Security.Principal.WindowsImpersonationContext impersonatedUser = null;
var newIdentity = new System.Security.Principal.WindowsIdentity(token);
impersonatedUser = newIdentity.Impersonate();
bool result = CopyFileEx(filename, tempFilepath, new CopyProgressRoutine(this.CopyProgressHandler), IntPtr.Zero, cancelp, 0);
if (impersonatedUser != null)
impersonatedUser.Undo();
impersonation.LogonAsUserEnd(token);
}

Here is a class I wrote in the past to make operations under Impersonation,
Check out how the token is created inside DoWorkUnderImpersonation()
with the credentials and the required constants to LogonUser() of advapi32.dll.
The required operation is made inside the DoWork() method, add your copy files logic there.
Call the static method DoWorkUnderImpersonation() from out side
// Implementation of the Impersonation class
Impersonation.DoWorkUnderImpersonation("DOMAIN", "USER", "PASSWORD");
public static class Impersonation
{
// obtains user token
[DllImport("advapi32.dll", SetLastError = true)]
public static extern bool LogonUser(string pszUsername, string pszDomain, string pszPassword,
int dwLogonType, int dwLogonProvider, ref IntPtr phToken);
// closes open handes returned by LogonUser
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
public extern static bool CloseHandle(IntPtr handle);
public static void DoWorkUnderImpersonation(string _domain, string _userName, string _password)
{
//elevate privileges before doing file copy to handle domain security
WindowsImpersonationContext impersonationContext = null;
IntPtr userHandle = IntPtr.Zero;
const int LOGON32_PROVIDER_DEFAULT = 0;
const int LOGON32_LOGON_INTERACTIVE = 2;
string domain = _domain;
string user = _userName;
string password = _password;
try
{
Debug.WriteLine("windows identify before impersonation: " + WindowsIdentity.GetCurrent().Name);
// if domain name was blank, assume local machine
if (domain == "")
domain = System.Environment.MachineName;
// Call LogonUser to get a token for the user
bool loggedOn = LogonUser(user,
domain,
password,
LOGON32_LOGON_INTERACTIVE,
LOGON32_PROVIDER_DEFAULT,
ref userHandle);
if (!loggedOn)
{
Debug.WriteLine("Exception impersonating user, error code: " + Marshal.GetLastWin32Error());
return;
}
// Begin impersonating the user
using (impersonationContext = WindowsIdentity.Impersonate(userHandle))
{
Debug.WriteLine("Main() windows identify after impersonation: " + WindowsIdentity.GetCurrent().Name);
//run the program with elevated privileges (like file copying from a domain server)
DoWork();
}
}
catch (Exception ex)
{
Console.Write("Exception impersonating user: " + ex.Message);
}
finally
{
// Clean up
if (impersonationContext != null)
{
impersonationContext.Undo();
}
if (userHandle != IntPtr.Zero)
{
CloseHandle(userHandle);
}
}
}
private static void DoWork()
{
try
{
// MAKE YOUR REQUIRED TASK HERE UNDER IMPERSONATION
}
catch (Exception ex)
{
Console.Write("error in Impersonation.DoWork() executing a task: " + ex.Message);
}
}
}

.NET 4.5 File.Copy ok, but file does not exist

strange behaviour in our production environment, these days.
I have the following:
try {
var sourcePath = ... // my source path
var destinationPath = ... // guess what? You're right, my destination path
File.Copy(sourcePath, destinationPath);
Log.Debug(string.Format("Image {0} copied successfully", imagename));
}
catch(Exception e) {
// exception handling
}
Both source and destination path are on a network share, a folder on an other (virtual) machine with a large number of files (> 500k).
From the last 2 days, the code above runs, logs the last line (the one stating that image have been copied), but if I check in the destination folder, the supposed destination file does not exist.
I thought that for any I/O error File.Copy would raise an exception, so this thing is driving me mad.
Please note that other code parts that write files in that folder are working correctly. Also, note that all files names are unique (business code not included for brevity is making sure of that), and I think an exception would be thrown or the file would be at least overwritten, in that case.
Has anyone faced the same problem? Possible causes? Any solution?
EDIT 2016-07-01 15:12 (GMT+0200)
Ok, folks, apparently files aren't being deleted at all... simply for apparently no reason at all, after they are copied they're left open in read+write mode from the client connected user.
I found this trying running the reader application on my computer, in debug mode, and trying to open one of the files i knew that were copied recently.
I got an exception stating that the file was opened by someone else, and that seemed weird to me.
Opening Computer Management in the remote server (the one which stores the files), then going to Shared Folders > Open Files, I found that the file was left open in read+write mode from the impersonated user that the web application that copies the files is impersonating to do that job.
Also a whole bunch of other files where in the same conditions, and many others where open in read mode.
I found also in Shared Folders > Sessions, an astronomical long list of session of the impersonated user, all with long idle time.
Since impersonation is used only to copy the files, and then is disposed, I shouldn't expect that, right?
I think maybe there is a problem in the way we impersonate the user during file copy, linked to the large number of files in the destination folder.
I'll check that.
END EDIT
Thanks,
Claudio Valerio

Found a solution, I think.
My problem was the code used for impersonating the user with write permissions on the destination folder.
(In my defence, all this project have been inherited from previous software company, and it's pretty massive, so keeping an eye on everything isn't that easy)
The impersonation process was wrapped in a class implementing IDisposable
public class Impersonator :
IDisposable
{
public Impersonator()
{
string userName = // get username from config
string password = // get password from config
string domainName = // get domain from config
ImpersonateValidUser(userName, domainName, password);
}
public void Dispose()
{
UndoImpersonation();
}
[DllImport("advapi32.dll", SetLastError = true)]
private static extern int LogonUser(
string lpszUserName,
string lpszDomain,
string lpszPassword,
int dwLogonType,
int dwLogonProvider,
ref IntPtr phToken);
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern int DuplicateToken(
IntPtr hToken,
int impersonationLevel,
ref IntPtr hNewToken);
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool RevertToSelf();
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
private static extern bool CloseHandle(
IntPtr handle);
private const int LOGON32_LOGON_INTERACTIVE = 2;
private const int LOGON32_PROVIDER_DEFAULT = 0;
private void ImpersonateValidUser(
string userName,
string domain,
string password)
{
WindowsIdentity tempWindowsIdentity = null;
IntPtr token = IntPtr.Zero;
IntPtr tokenDuplicate = IntPtr.Zero;
try
{
if (RevertToSelf())
{
if (LogonUser(
userName,
domain,
password,
LOGON32_LOGON_INTERACTIVE,
LOGON32_PROVIDER_DEFAULT,
ref token) != 0)
{
if (DuplicateToken(token, 2, ref tokenDuplicate) != 0)
{
tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);
impersonationContext = tempWindowsIdentity.Impersonate();
}
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
finally
{
if (token != IntPtr.Zero)
{
CloseHandle(token);
}
if (tokenDuplicate != IntPtr.Zero)
{
CloseHandle(tokenDuplicate);
}
}
}
private void UndoImpersonation()
{
if (impersonationContext != null)
{
impersonationContext.Undo();
}
}
private WindowsImpersonationContext impersonationContext = null;
}
This class is used this way:
using(new Impersonator())
{
// do stuff with files in here
}
My suspect was that closing the handlers of the impersonated user, somehow, it could break something in the way that windows handles file open by the impersonated user through a network share, as in my case, leaving shared files open in read+write mode, preventing any other process/user to open them.
I modified the Impersonator class as follows:
public class Impersonator :
IDisposable
{
public Impersonator()
{
string userName = // get username from config
string password = // get password from config
string domainName = // get domain from config
ImpersonateValidUser(userName, domainName, password);
}
public void Dispose()
{
UndoImpersonation();
impersonationContext.Dispose();
}
[DllImport("advapi32.dll", SetLastError = true)]
private static extern int LogonUser(
string lpszUserName,
string lpszDomain,
string lpszPassword,
int dwLogonType,
int dwLogonProvider,
ref IntPtr phToken);
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern int DuplicateToken(
IntPtr hToken,
int impersonationLevel,
ref IntPtr hNewToken);
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool RevertToSelf();
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
private static extern bool CloseHandle(
IntPtr handle);
private const int LOGON32_LOGON_INTERACTIVE = 2;
private const int LOGON32_PROVIDER_DEFAULT = 0;
private void ImpersonateValidUser(
string userName,
string domain,
string password)
{
WindowsIdentity tempWindowsIdentity = null;
token = IntPtr.Zero;
tokenDuplicate = IntPtr.Zero;
try
{
if (RevertToSelf())
{
if (LogonUser(
userName,
domain,
password,
LOGON32_LOGON_INTERACTIVE,
LOGON32_PROVIDER_DEFAULT,
ref token) != 0)
{
if (DuplicateToken(token, 2, ref tokenDuplicate) != 0)
{
tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);
impersonationContext = tempWindowsIdentity.Impersonate();
}
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
finally
{
}
}
private void UndoImpersonation()
{
try
{
if (impersonationContext != null)
{
impersonationContext.Undo();
}
}
finally
{
if (token != IntPtr.Zero)
{
CloseHandle(token);
}
if (tokenDuplicate != IntPtr.Zero)
{
CloseHandle(tokenDuplicate);
}
}
}
private WindowsImpersonationContext impersonationContext = null;
private IntPtr token;
private IntPtr tokenDuplicate;
}
Basically I moved the handlers closing in the UndoImpersonation method. Also I had a doubt about leaving the impersonationContext not explicitly disposed, si I disposed it in the Dispose method of the Impersonator class.
Since I put in production this update, I hadn't any other issue with this code, and not any other shared file left open in read+write mode on the destination server.
Maybe not the optimal solution (I still have a whole bunch of sessions in Computer Management > Shared Folders > Sessions, but this seems not harming the system, for now.
If anyone have some additional comment, suggestion or depth study about this situation, I will be please to read.
Thanks,
Claudio

.NET Start Process with higher rights

I am trying to execute a program with admin rights through a C# application, which gets invoked with user rights only.
Code
ProcessStartInfo psi;
try
{
psi = new ProcessStartInfo(#"WINZIP32.EXE");
psi.UseShellExecute = false;
SecureString pw = new SecureString();
pw.AppendChar('p');
pw.AppendChar('a');
pw.AppendChar('s');
pw.AppendChar('s');
pw.AppendChar('w');
pw.AppendChar('o');
pw.AppendChar('r');
pw.AppendChar('d');
psi.Password = pw;
psi.UserName = "administrator";
Process.Start(psi);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
It does start winzip, but only with user rights. Is there something I am doing wrong or is it even possible to start a process with higher rights?
thank you!
Edit:
Here is the reason behind the question, maybe it helps to understand what i actually need.
I used winzip for example to get a general idea what's incorrect with my code. The actual problem is, our company uses 2 versions of a program. But before you start any of the versions you need to import a dll file with regsvr32 (with admin rights). Now I would like to write a program that let the user select the version, import the dll and starts the correct application.

You need to set ProcessStartInfo.UseShellExecute to true and ProcessStartInfo.Verb to runas:
Process process = null;
ProcessStartInfo processStartInfo = new ProcessStartInfo();
processStartInfo.FileName = "WINZIP32.EXE";
processStartInfo.Verb = "runas";
processStartInfo.WindowStyle = ProcessWindowStyle.Normal;
processStartInfo.UseShellExecute = true;
process = Process.Start(processStartInfo);
This will cause the application to run as the administrator. UAC will however prompt the user to confirm. If this is not desirable then you'll need to add a manifest to permanently elevate the host process privilages.

You can run a process as another user(even an administrator) using the CreateProcessAsUser function (Win32 API).
CreateProcessAsUser accepts a user token as the first parameter, that is an impersonation token.
You have to use DLLImport to load the function from the Windows DLL.
Take a look at this example implementation that i have used in one of my projects :
[StructLayout(LayoutKind.Sequential)]
internal struct PROCESS_INFORMATION
{
public IntPtr hProcess;
public IntPtr hThread;
public uint dwProcessId;
public uint dwThreadId;
}
[StructLayout(LayoutKind.Sequential)]
internal struct SECURITY_ATTRIBUTES
{
public uint nLength;
public IntPtr lpSecurityDescriptor;
public bool bInheritHandle;
}
[StructLayout(LayoutKind.Sequential)]
public struct STARTUPINFO
{
public uint cb;
public string lpReserved;
public string lpDesktop;
public string lpTitle;
public uint dwX;
public uint dwY;
public uint dwXSize;
public uint dwYSize;
public uint dwXCountChars;
public uint dwYCountChars;
public uint dwFillAttribute;
public uint dwFlags;
public short wShowWindow;
public short cbReserved2;
public IntPtr lpReserved2;
public IntPtr hStdInput;
public IntPtr hStdOutput;
public IntPtr hStdError;
}
internal enum SECURITY_IMPERSONATION_LEVEL
{
SecurityAnonymous,
SecurityIdentification,
SecurityImpersonation,
SecurityDelegation
}
internal enum TOKEN_TYPE
{
TokenPrimary = 1,
TokenImpersonation
}
public class ProcessAsUser
{
[DllImport("advapi32.dll", SetLastError = true)]
private static extern bool CreateProcessAsUser(
IntPtr hToken,
string lpApplicationName,
string lpCommandLine,
ref SECURITY_ATTRIBUTES lpProcessAttributes,
ref SECURITY_ATTRIBUTES lpThreadAttributes,
bool bInheritHandles,
uint dwCreationFlags,
IntPtr lpEnvironment,
string lpCurrentDirectory,
ref STARTUPINFO lpStartupInfo,
out PROCESS_INFORMATION lpProcessInformation);
[DllImport("advapi32.dll", EntryPoint = "DuplicateTokenEx", SetLastError = true)]
private static extern bool DuplicateTokenEx(
IntPtr hExistingToken,
uint dwDesiredAccess,
ref SECURITY_ATTRIBUTES lpThreadAttributes,
Int32 ImpersonationLevel,
Int32 dwTokenType,
ref IntPtr phNewToken);
[DllImport("advapi32.dll", SetLastError = true)]
private static extern bool OpenProcessToken(
IntPtr ProcessHandle,
UInt32 DesiredAccess,
ref IntPtr TokenHandle);
[DllImport("userenv.dll", SetLastError = true)]
private static extern bool CreateEnvironmentBlock(
ref IntPtr lpEnvironment,
IntPtr hToken,
bool bInherit);
[DllImport("userenv.dll", SetLastError = true)]
private static extern bool DestroyEnvironmentBlock(
IntPtr lpEnvironment);
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool CloseHandle(
IntPtr hObject);
private const short SW_SHOW = 5;
private const uint TOKEN_QUERY = 0x0008;
private const uint TOKEN_DUPLICATE = 0x0002;
private const uint TOKEN_ASSIGN_PRIMARY = 0x0001;
private const int GENERIC_ALL_ACCESS = 0x10000000;
private const int STARTF_USESHOWWINDOW = 0x00000001;
private const int STARTF_FORCEONFEEDBACK = 0x00000040;
private const uint CREATE_UNICODE_ENVIRONMENT = 0x00000400;
private const int STARTF_RUNFULLSCREEN = 0x00000020;
private static bool LaunchProcessAsUser(string cmdLine, IntPtr token, IntPtr envBlock)
{
bool result = false;
PROCESS_INFORMATION pi = new PROCESS_INFORMATION();
SECURITY_ATTRIBUTES saProcess = new SECURITY_ATTRIBUTES();
SECURITY_ATTRIBUTES saThread = new SECURITY_ATTRIBUTES();
saProcess.nLength = (uint)Marshal.SizeOf(saProcess);
saThread.nLength = (uint)Marshal.SizeOf(saThread);
STARTUPINFO si = new STARTUPINFO();
si.cb = (uint)Marshal.SizeOf(si);
//if this member is NULL, the new process inherits the desktop
//and window station of its parent process. If this member is
//an empty string, the process does not inherit the desktop and
//window station of its parent process; instead, the system
//determines if a new desktop and window station need to be created.
//If the impersonated user already has a desktop, the system uses the
//existing desktop.
si.lpDesktop = #"WinSta0\Default"; //Modify as needed
si.dwFlags = STARTF_USESHOWWINDOW | STARTF_FORCEONFEEDBACK;
si.wShowWindow = SW_SHOW;
//Set other si properties as required.
result = CreateProcessAsUser(
token,
null,
cmdLine,
ref saProcess,
ref saThread,
false,
CREATE_UNICODE_ENVIRONMENT,
envBlock,
null,
ref si,
out pi);
if (result == false)
{
int error = Marshal.GetLastWin32Error();
string message = String.Format("CreateProcessAsUser Error: {0}", error);
Debug.WriteLine(message);
}
return result;
}
/// <summary>
/// LaunchProcess As User Overloaded for Window Mode
/// </summary>
/// <param name="cmdLine"></param>
/// <param name="token"></param>
/// <param name="envBlock"></param>
/// <param name="WindowMode"></param>
/// <returns></returns>
private static bool LaunchProcessAsUser(string cmdLine, IntPtr token, IntPtr envBlock,uint WindowMode)
{
bool result = false;
PROCESS_INFORMATION pi = new PROCESS_INFORMATION();
SECURITY_ATTRIBUTES saProcess = new SECURITY_ATTRIBUTES();
SECURITY_ATTRIBUTES saThread = new SECURITY_ATTRIBUTES();
saProcess.nLength = (uint)Marshal.SizeOf(saProcess);
saThread.nLength = (uint)Marshal.SizeOf(saThread);
STARTUPINFO si = new STARTUPINFO();
si.cb = (uint)Marshal.SizeOf(si);
//if this member is NULL, the new process inherits the desktop
//and window station of its parent process. If this member is
//an empty string, the process does not inherit the desktop and
//window station of its parent process; instead, the system
//determines if a new desktop and window station need to be created.
//If the impersonated user already has a desktop, the system uses the
//existing desktop.
si.lpDesktop = #"WinSta0\Default"; //Default Vista/7 Desktop Session
si.dwFlags = STARTF_USESHOWWINDOW | STARTF_FORCEONFEEDBACK;
//Check the Startup Mode of the Process
if (WindowMode == 1)
si.wShowWindow = SW_SHOW;
else if (WindowMode == 2)
{ //Do Nothing
}
else if (WindowMode == 3)
si.wShowWindow = 0; //Hide Window
else if (WindowMode == 4)
si.wShowWindow = 3; //Maximize Window
else if (WindowMode == 5)
si.wShowWindow = 6; //Minimize Window
else
si.wShowWindow = SW_SHOW;
//Set other si properties as required.
result = CreateProcessAsUser(
token,
null,
cmdLine,
ref saProcess,
ref saThread,
false,
CREATE_UNICODE_ENVIRONMENT,
envBlock,
null,
ref si,
out pi);
if (result == false)
{
int error = Marshal.GetLastWin32Error();
string message = String.Format("CreateProcessAsUser Error: {0}", error);
Debug.WriteLine(message);
}
return result;
}
private static IntPtr GetPrimaryToken(int processId)
{
IntPtr token = IntPtr.Zero;
IntPtr primaryToken = IntPtr.Zero;
bool retVal = false;
Process p = null;
try
{
p = Process.GetProcessById(processId);
}
catch (ArgumentException)
{
string details = String.Format("ProcessID {0} Not Available", processId);
Debug.WriteLine(details);
throw;
}
//Gets impersonation token
retVal = OpenProcessToken(p.Handle, TOKEN_DUPLICATE, ref token);
if (retVal == true)
{
SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES();
sa.nLength = (uint)Marshal.SizeOf(sa);
//Convert the impersonation token into Primary token
retVal = DuplicateTokenEx(
token,
TOKEN_ASSIGN_PRIMARY | TOKEN_DUPLICATE | TOKEN_QUERY,
ref sa,
(int)SECURITY_IMPERSONATION_LEVEL.SecurityIdentification,
(int)TOKEN_TYPE.TokenPrimary,
ref primaryToken);
//Close the Token that was previously opened.
CloseHandle(token);
if (retVal == false)
{
string message = String.Format("DuplicateTokenEx Error: {0}", Marshal.GetLastWin32Error());
Debug.WriteLine(message);
}
}
else
{
string message = String.Format("OpenProcessToken Error: {0}", Marshal.GetLastWin32Error());
Debug.WriteLine(message);
}
//We'll Close this token after it is used.
return primaryToken;
}
private static IntPtr GetEnvironmentBlock(IntPtr token)
{
IntPtr envBlock = IntPtr.Zero;
bool retVal = CreateEnvironmentBlock(ref envBlock, token, false);
if (retVal == false)
{
//Environment Block, things like common paths to My Documents etc.
//Will not be created if "false"
//It should not adversley affect CreateProcessAsUser.
string message = String.Format("CreateEnvironmentBlock Error: {0}", Marshal.GetLastWin32Error());
Debug.WriteLine(message);
}
return envBlock;
}
public static bool Launch(string appCmdLine /*,int processId*/)
{
bool ret = false;
//Either specify the processID explicitly
//Or try to get it from a process owned by the user.
//In this case assuming there is only one explorer.exe
Process[] ps = Process.GetProcessesByName("explorer");
int processId = -1;//=processId
if (ps.Length > 0)
{
processId = ps[0].Id;
}
if (processId > 1)
{
IntPtr token = GetPrimaryToken(processId);
if (token != IntPtr.Zero)
{
IntPtr envBlock = GetEnvironmentBlock(token);
ret = LaunchProcessAsUser(appCmdLine, token, envBlock);
if (envBlock != IntPtr.Zero)
DestroyEnvironmentBlock(envBlock);
CloseHandle(token);
}
}
return ret;
}

Ref:
How to start a Process as administrator mode in C#
Elevating process privilege programmatically?
var psi = new ProcessStartInfo
{
FileName = "notepad",
UserName = "admin",
Domain = "",
Password = pass,
UseShellExecute = true,
RedirectStandardOutput = true,
RedirectStandardError = true,
Verb = "runas";
};
Process.Start(psi);
//
var pass = new SecureString();
pass.AppendChar('s');
pass.AppendChar('e');
pass.AppendChar('c');
pass.AppendChar('r');
pass.AppendChar('e');
pass.AppendChar('t');
Process.Start("notepad", "admin", pass, "");
//Vista or higher check
if (System.Environment.OSVersion.Version.Major >= 6)
{
p.StartInfo.Verb = "runas";
}
Ref: How to run/start a new process with admin rights? ASP.net Forum
Another way is to impersonate the admin user. You can do this by
calling the Logon function and impersonate the user whose token you
will get then. For impersonating a user in code, look at:
WindowsImpersonationContext
Class
. Use the check
http://www.csharpfriends.com/Forums/ShowPost.aspx?PostID=31611 for
GetCurrentUser to see whether impersonation succeeded.
Code Snippet:
System.Diagnostics.Process process = null;
System.Diagnostics.ProcessStartInfo processStartInfo;
processStartInfo = new System.Diagnostics.ProcessStartInfo();
processStartInfo.FileName = "regedit.exe";
if (System.Environment.OSVersion.Version.Major >= 6) // Windows Vista or higher
{
processStartInfo.Verb = "runas";
}
else
{
// No need to prompt to run as admin
}
processStartInfo.Arguments = "";
processStartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
processStartInfo.UseShellExecute = true;
try
{
process = System.Diagnostics.Process.Start(processStartInfo);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
if (process != null)
{
process.Dispose();
}
}
//Try this with administrator login, i have not tested yet..
[DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword,
int dwLogonType, int dwLogonProvider, out SafeTokenHandle phToken);
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
public extern static bool CloseHandle(IntPtr handle);
// Test harness.
// If you incorporate this code into a DLL, be sure to demand FullTrust.
[PermissionSetAttribute(SecurityAction.Demand, Name = "FullTrust")]
private void button1_Click(object sender, EventArgs e)
{
SafeTokenHandle safeTokenHandle;
const int LOGON32_PROVIDER_DEFAULT = 0;
//This parameter causes LogonUser to create a primary token.
const int LOGON32_LOGON_INTERACTIVE = 2;
bool returnValue = LogonUser("administrator", "", "password",
LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT,
out safeTokenHandle);
Console.WriteLine("LogonUser called.");
if (false == returnValue)
{
int ret = Marshal.GetLastWin32Error();
Console.WriteLine("LogonUser failed with error code : {0}", ret);
throw new System.ComponentModel.Win32Exception(ret);
}
using (safeTokenHandle)
{
Console.WriteLine("Did LogonUser Succeed? " + (returnValue ? "Yes" : "No"));
Console.WriteLine("Value of Windows NT token: " + safeTokenHandle);
// Check the identity.
Console.WriteLine("Before impersonation: "
+ WindowsIdentity.GetCurrent().Name);
// Use the token handle returned by LogonUser.
WindowsIdentity newId = new WindowsIdentity(safeTokenHandle.DangerousGetHandle());
using (WindowsImpersonationContext impersonatedUser = newId.Impersonate())
{
System.Diagnostics.Process process = null;
System.Diagnostics.ProcessStartInfo processStartInfo;
processStartInfo = new System.Diagnostics.ProcessStartInfo();
processStartInfo.FileName = "regedit.exe";
//if (System.Environment.OSVersion.Version.Major >= 6) // Windows Vista or higher
//{
// processStartInfo.Verb = "runas";
//}
//else
//{
// // No need to prompt to run as admin
//}
processStartInfo.Arguments = "";
processStartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
processStartInfo.UseShellExecute = true;
try
{
process = System.Diagnostics.Process.Start(processStartInfo);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
if (process != null)
{
process.Dispose();
}
}
// Check the identity.
Console.WriteLine("After impersonation: "
+ WindowsIdentity.GetCurrent().Name);
}
// Releasing the context object stops the impersonation
// Check the identity.
Console.WriteLine("After closing the context: " + WindowsIdentity.GetCurrent().Name);
}
}

How can I impersonate a webservice file (asmx) from code?

Until recently, I've used the "<impersonate >" tag in web.config, followed by proper credentials.
Now I'm trying to add another asmx file, that will impersonate to a different account, and trying to do that from code.
Question is -
How to impersonate (on every request) from code in an asmx file (webservice) ?
(I'm using C#)
I guess the code should be in the ctor of the asmx class, but I'm not sure what the could should be.
I've googled thru many examples but haven't found a decent code that do what I wants.
Thank you in advance!

See sample code how you can do it:
using System;
using System.Runtime.InteropServices;
using System.Security.Principal;
using System.Security.Permissions;
[assembly: SecurityPermissionAttribute(SecurityAction.RequestMinimum, UnmanagedCode = true)]
[assembly: PermissionSetAttribute(SecurityAction.RequestMinimum, Name = "FullTrust")]
public class ImpersonationDemo
{
[DllImport("advapi32.dll", SetLastError = true)]
public static extern bool LogonUser(
String lpszUsername,
String lpszDomain,
String lpszPassword,
int dwLogonType,
int dwLogonProvider,
ref IntPtr phToken);
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
public extern static bool CloseHandle(IntPtr handle);
// Test harness.
// If you incorporate this code into a DLL, be sure to demand FullTrust.
[PermissionSetAttribute(SecurityAction.Demand, Name = "FullTrust")]
public static void Main(string[] args)
{
IntPtr tokenHandle = new IntPtr(0);
try
{
string userName, domainName;
// Get the user token for the specified user, domain, and password using the
// unmanaged LogonUser method.
// The local machine name can be used for the domain name to impersonate a user on this machine.
Console.Write("Enter the name of the domain on which to log on: ");
domainName = Console.ReadLine();
Console.Write("Enter the login of a user on {0} that you wish to impersonate: ", domainName);
userName = Console.ReadLine();
Console.Write("Enter the password for {0}: ", userName);
const int LOGON32_PROVIDER_DEFAULT = 0;
//This parameter causes LogonUser to create a primary token.
const int LOGON32_LOGON_INTERACTIVE = 2;
tokenHandle = IntPtr.Zero;
// Call LogonUser to obtain a handle to an access token.
bool returnValue = LogonUser(
userName,
domainName,
Console.ReadLine(),
3,
LOGON32_PROVIDER_DEFAULT,
ref tokenHandle);
Console.WriteLine("LogonUser called.");
if (false == returnValue)
{
int ret = Marshal.GetLastWin32Error();
Console.WriteLine("LogonUser failed with error code : {0}", ret);
throw new System.ComponentModel.Win32Exception(ret);
}
Console.WriteLine("Did LogonUser Succeed? " + (returnValue ? "Yes" : "No"));
Console.WriteLine("Value of Windows NT token: " + tokenHandle);
// Check the identity.
Console.WriteLine("Before impersonation: " + WindowsIdentity.GetCurrent().Name);
// Use the token handle returned by LogonUser.
WindowsIdentity newId = new WindowsIdentity(tokenHandle);
using (WindowsImpersonationContext impersonatedUser = newId.Impersonate())
{
// Check the identity. Here you shoul place code that will be executed on belaf of other login.
Console.WriteLine("After impersonation: " + WindowsIdentity.GetCurrent().Name);
GC.KeepAlive(impersonatedUser);
}
// Check the identity.
Console.WriteLine("After Undo: " + WindowsIdentity.GetCurrent().Name);
// Free the tokens.
if (tokenHandle != IntPtr.Zero)
CloseHandle(tokenHandle);
}
catch (Exception ex)
{
Console.WriteLine("Exception occurred. " + ex.Message);
}
}
}

If you have impersonate set to ON in your web.config you can specify a different credential via:
new System.Net.NetworkCredential("username", "password", "domain");
I have also found a good article How to impersonate a user given her token
It shows how to attach a diffrent WindowsIdentity to a given thread