C# – Permissions problem when starting .NET app from .NET service as a different user

cnetservice

I'm trying to start a .NET application under a different user from a .NET service. The idea is to create a sandboxed hosting application in windows. In the service, I programatically created the user in windows, create a folder for that user, and download the host .exe from a server into that folder. I then I run the host .exe using System.Diagnostics.Process. Here is the StartInfo for the process:

_process = new Process
{
    StartInfo =
    {
        Arguments = " -debug",
        FileName = instanceDirectory + "host.exe",
        WorkingDirectory = instanceDirectory,
        UseShellExecute = false,
        RedirectStandardError = true,
        RedirectStandardOutput = true,
        RedirectStandardInput = true,
        UserName = Helpers.GetUserNameForInstance(_hostid),
        Password = _hostpass,
        Domain = ""
    },
    EnableRaisingEvents = true
};

When I run the service as a SERVICE, the process crashes instantly with an error code of -1073741502. but when I run the service as the same user specified in the windows service but interactively in the console, everything works fine. This only happens whenever running the service as a SERVICE and not directly in the console.

Any help would be MUCH appreciated. This has been a headache for a long time now and this is a last resort 🙁

Best Answer

It seems like using the new Process() with a username and password and the Service mode "doesn't compute" :)

Quote from MSDN:

You can change the parameters specified in the StartInfo property up to the time that you call the Start method on the process. After you start the process, changing the StartInfo values does not affect or restart the associated process. If you call the Start(ProcessStartInfo) method with the ProcessStartInfo..::.UserName and ProcessStartInfo..::.Password properties set, the unmanaged CreateProcessWithLogonW function is called, which starts the process in a new window even if the CreateNoWindow property value is true or the WindowStyle property value is Hidden.

Furthermore, looking at the CreateProcessWithLogonW documentation:

lpStartupInfo [in]

A pointer to a STARTUPINFO structure. The application must add permission for the specified user account to the specified window station and desktop, even for WinSta0\Default.

If the lpDesktop member is NULL or an empty string, the new process inherits the desktop and window station of its parent process. The application must add permission for the specified user account to the inherited window station and desktop.

There is no lpDesktop in the .NET StartupInfo, on the other hand the SERVICE user has no desktop, which could cause your problem.

Long story short, try to set the LoadUserProfile to true to load the user's information from the registry, or maybe you need to set the working directory, etc.

To further investigate, your should check your environment and maybe log which files are accessed using FileMon.

Related Solutions

C# – Using Process.Start() to start a process as a different user from within a Windows Service

I seem to have a working implementation (Works On My Machine(TM)) for the following scenarios:

Batch File, .NET Console Assembly, .NET Windows Forms application.

Here's how:

I have a windows service running as the Administrator user. I add the following policies to the Administrator user:

Log on as a service
Act as part of the operating system
Adjust memory quotas for a process
Replace a process level token

These policies can be added by opening Control Panel/ Administrative Tools / Local Security Policy / User Rights Assignment. Once they are set, the policies don't take effect until next login. You can use another user instead of the Administrator, which might make things a bit safer :)

Now, my windows service has the required permissions to start jobs as other users. When a job needs to be started the service executes a seperate assembly ("Starter" .NET console assembly) which initiates the process for me.

The following code, located in the windows service, executes my "Starter" console assembly:

Process proc = null;
System.Diagnostics.ProcessStartInfo info;
string domain = string.IsNullOrEmpty(row.Domain) ? "." : row.Domain;
info = new ProcessStartInfo("Starter.exe");
info.Arguments = cmd + " " + domain + " " + username + " " + password + " " + args;
info.WorkingDirectory = Path.GetDirectoryName(cmd);
info.UseShellExecute = false;
info.RedirectStandardError = true;
info.RedirectStandardOutput = true;
proc = System.Diagnostics.Process.Start(info);

The console assembly then starts the target process via interop calls:

class Program
{
    #region Interop

    [StructLayout(LayoutKind.Sequential)]
    public struct LUID
    {
        public UInt32 LowPart;
        public Int32 HighPart;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct LUID_AND_ATTRIBUTES
    {
        public LUID Luid;
        public UInt32 Attributes;
    }

    public struct TOKEN_PRIVILEGES
    {
        public UInt32 PrivilegeCount;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)]
        public LUID_AND_ATTRIBUTES[] Privileges;
    }

    enum TOKEN_INFORMATION_CLASS
    {
        TokenUser = 1,
        TokenGroups,
        TokenPrivileges,
        TokenOwner,
        TokenPrimaryGroup,
        TokenDefaultDacl,
        TokenSource,
        TokenType,
        TokenImpersonationLevel,
        TokenStatistics,
        TokenRestrictedSids,
        TokenSessionId,
        TokenGroupsAndPrivileges,
        TokenSessionReference,
        TokenSandBoxInert,
        TokenAuditPolicy,
        TokenOrigin,
        TokenElevationType,
        TokenLinkedToken,
        TokenElevation,
        TokenHasRestrictions,
        TokenAccessInformation,
        TokenVirtualizationAllowed,
        TokenVirtualizationEnabled,
        TokenIntegrityLevel,
        TokenUIAccess,
        TokenMandatoryPolicy,
        TokenLogonSid,
        MaxTokenInfoClass
    }

    [Flags]
    enum CreationFlags : uint
    {
        CREATE_BREAKAWAY_FROM_JOB = 0x01000000,
        CREATE_DEFAULT_ERROR_MODE = 0x04000000,
        CREATE_NEW_CONSOLE = 0x00000010,
        CREATE_NEW_PROCESS_GROUP = 0x00000200,
        CREATE_NO_WINDOW = 0x08000000,
        CREATE_PROTECTED_PROCESS = 0x00040000,
        CREATE_PRESERVE_CODE_AUTHZ_LEVEL = 0x02000000,
        CREATE_SEPARATE_WOW_VDM = 0x00001000,
        CREATE_SUSPENDED = 0x00000004,
        CREATE_UNICODE_ENVIRONMENT = 0x00000400,
        DEBUG_ONLY_THIS_PROCESS = 0x00000002,
        DEBUG_PROCESS = 0x00000001,
        DETACHED_PROCESS = 0x00000008,
        EXTENDED_STARTUPINFO_PRESENT = 0x00080000
    }

    public enum TOKEN_TYPE
    {
        TokenPrimary = 1,
        TokenImpersonation
    }

    public enum SECURITY_IMPERSONATION_LEVEL
    {
        SecurityAnonymous,
        SecurityIdentification,
        SecurityImpersonation,
        SecurityDelegation
    }

    [Flags]
    enum LogonFlags
    {
        LOGON_NETCREDENTIALS_ONLY = 2,
        LOGON_WITH_PROFILE = 1
    }

    enum LOGON_TYPE
    {
        LOGON32_LOGON_INTERACTIVE = 2,
        LOGON32_LOGON_NETWORK,
        LOGON32_LOGON_BATCH,
        LOGON32_LOGON_SERVICE,
        LOGON32_LOGON_UNLOCK = 7,
        LOGON32_LOGON_NETWORK_CLEARTEXT,
        LOGON32_LOGON_NEW_CREDENTIALS
    }

    enum LOGON_PROVIDER
    {
        LOGON32_PROVIDER_DEFAULT,
        LOGON32_PROVIDER_WINNT35,
        LOGON32_PROVIDER_WINNT40,
        LOGON32_PROVIDER_WINNT50
    }

    #region _SECURITY_ATTRIBUTES
    //typedef struct _SECURITY_ATTRIBUTES {  
    //    DWORD nLength;  
    //    LPVOID lpSecurityDescriptor;  
    //    BOOL bInheritHandle;
    //} SECURITY_ATTRIBUTES,  *PSECURITY_ATTRIBUTES,  *LPSECURITY_ATTRIBUTES;
    #endregion
    struct SECURITY_ATTRIBUTES
    {
        public uint Length;
        public IntPtr SecurityDescriptor;
        public bool InheritHandle;
    }

    [Flags] enum SECURITY_INFORMATION : uint
    {
        OWNER_SECURITY_INFORMATION        = 0x00000001,
        GROUP_SECURITY_INFORMATION        = 0x00000002,
        DACL_SECURITY_INFORMATION         = 0x00000004,
        SACL_SECURITY_INFORMATION         = 0x00000008,
        UNPROTECTED_SACL_SECURITY_INFORMATION = 0x10000000,
        UNPROTECTED_DACL_SECURITY_INFORMATION = 0x20000000,
        PROTECTED_SACL_SECURITY_INFORMATION   = 0x40000000,
        PROTECTED_DACL_SECURITY_INFORMATION   = 0x80000000
    }

    #region _SECURITY_DESCRIPTOR
    //typedef struct _SECURITY_DESCRIPTOR {
    //  UCHAR  Revision;
    //  UCHAR  Sbz1;
    //  SECURITY_DESCRIPTOR_CONTROL  Control;
    //  PSID  Owner;
    //  PSID  Group;
    //  PACL  Sacl;
    //  PACL  Dacl;
    //} SECURITY_DESCRIPTOR, *PISECURITY_DESCRIPTOR;
    #endregion
    [StructLayoutAttribute(LayoutKind.Sequential)]
    struct SECURITY_DESCRIPTOR
    {
        public byte revision;
        public byte size;
        public short control; // public SECURITY_DESCRIPTOR_CONTROL control;
        public IntPtr owner;
        public IntPtr group;
        public IntPtr sacl;
        public IntPtr dacl;
    }

    #region _STARTUPINFO
    //typedef struct _STARTUPINFO {  
    //    DWORD cb;  
    //    LPTSTR lpReserved;  
    //    LPTSTR lpDesktop;  
    //    LPTSTR lpTitle;  
    //    DWORD dwX;  
    //    DWORD dwY;  
    //    DWORD dwXSize;  
    //    DWORD dwYSize;  
    //    DWORD dwXCountChars;  
    //    DWORD dwYCountChars;  
    //    DWORD dwFillAttribute;  
    //    DWORD dwFlags;  
    //    WORD wShowWindow;  
    //    WORD cbReserved2;  
    //    LPBYTE lpReserved2;  
    //    HANDLE hStdInput;  
    //    HANDLE hStdOutput;  
    //    HANDLE hStdError; 
    //} STARTUPINFO,  *LPSTARTUPINFO;
    #endregion
    struct STARTUPINFO
    {
        public uint cb;
        [MarshalAs(UnmanagedType.LPTStr)]
        public string Reserved;
        [MarshalAs(UnmanagedType.LPTStr)]
        public string Desktop;
        [MarshalAs(UnmanagedType.LPTStr)]
        public string Title;
        public uint X;
        public uint Y;
        public uint XSize;
        public uint YSize;
        public uint XCountChars;
        public uint YCountChars;
        public uint FillAttribute;
        public uint Flags;
        public ushort ShowWindow;
        public ushort Reserverd2;
        public byte bReserverd2;
        public IntPtr StdInput;
        public IntPtr StdOutput;
        public IntPtr StdError;
    }

    #region _PROCESS_INFORMATION
    //typedef struct _PROCESS_INFORMATION {  
    //  HANDLE hProcess;  
    //  HANDLE hThread;  
    //  DWORD dwProcessId;  
    //  DWORD dwThreadId; } 
    //  PROCESS_INFORMATION,  *LPPROCESS_INFORMATION;
    #endregion
    [StructLayout(LayoutKind.Sequential)]
    struct PROCESS_INFORMATION
    {
        public IntPtr Process;
        public IntPtr Thread;
        public uint ProcessId;
        public uint ThreadId;
    }

    [DllImport("advapi32.dll", SetLastError = true)]
    static extern bool InitializeSecurityDescriptor(IntPtr pSecurityDescriptor, uint dwRevision);
    const uint SECURITY_DESCRIPTOR_REVISION = 1;

    [DllImport("advapi32.dll", SetLastError = true)]
    static extern bool SetSecurityDescriptorDacl(ref SECURITY_DESCRIPTOR sd, bool daclPresent, IntPtr dacl, bool daclDefaulted);

    [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    extern static bool DuplicateTokenEx(
        IntPtr hExistingToken,
        uint dwDesiredAccess,
        ref SECURITY_ATTRIBUTES lpTokenAttributes,
        SECURITY_IMPERSONATION_LEVEL ImpersonationLevel,
        TOKEN_TYPE TokenType,
        out IntPtr phNewToken);

    [DllImport("advapi32.dll", SetLastError = true)]
    public static extern bool LogonUser(
        string lpszUsername,
        string lpszDomain,
        string lpszPassword,
        int dwLogonType,
        int dwLogonProvider,
        out IntPtr phToken
        );

    #region GetTokenInformation
    //BOOL WINAPI GetTokenInformation(
    //  __in       HANDLE TokenHandle,
    //  __in       TOKEN_INFORMATION_CLASS TokenInformationClass,
    //  __out_opt  LPVOID TokenInformation,
    //  __in       DWORD TokenInformationLength,
    //  __out      PDWORD ReturnLength
    //);
    #endregion
    [DllImport("advapi32.dll", SetLastError = true)]
    static extern bool GetTokenInformation(
        IntPtr TokenHandle,
        TOKEN_INFORMATION_CLASS TokenInformationClass,
        IntPtr TokenInformation,
        int TokenInformationLength,
        out int ReturnLength
        );


    #region CreateProcessAsUser
    //        BOOL WINAPI CreateProcessAsUser(
    //  __in_opt     HANDLE hToken,
    //  __in_opt     LPCTSTR lpApplicationName,
    //  __inout_opt  LPTSTR lpCommandLine,
    //  __in_opt     LPSECURITY_ATTRIBUTES lpProcessAttributes,
    //  __in_opt     LPSECURITY_ATTRIBUTES lpThreadAttributes,
    //  __in         BOOL bInheritHandles,
    //  __in         DWORD dwCreationFlags,
    //  __in_opt     LPVOID lpEnvironment,
    //  __in_opt     LPCTSTR lpCurrentDirectory,
    //  __in         LPSTARTUPINFO lpStartupInfo,
    //  __out        LPPROCESS_INFORMATION lpProcessInformation);
    #endregion
    [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    static extern bool CreateProcessAsUser(
        IntPtr Token, 
        [MarshalAs(UnmanagedType.LPTStr)] string ApplicationName,
        [MarshalAs(UnmanagedType.LPTStr)] string CommandLine,
        ref SECURITY_ATTRIBUTES ProcessAttributes, 
        ref SECURITY_ATTRIBUTES ThreadAttributes, 
        bool InheritHandles,
        uint CreationFlags, 
        IntPtr Environment, 
        [MarshalAs(UnmanagedType.LPTStr)] string CurrentDirectory, 
        ref STARTUPINFO StartupInfo, 
        out PROCESS_INFORMATION ProcessInformation);

    #region CloseHandle
    //BOOL WINAPI CloseHandle(
    //      __in          HANDLE hObject
    //        );
    #endregion
    [DllImport("Kernel32.dll")]
    extern static int CloseHandle(IntPtr handle);

    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
    internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall, ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen);

    [DllImport("advapi32.dll", SetLastError = true)]
    internal static extern bool LookupPrivilegeValue(string host, string name, ref long pluid);

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    internal struct TokPriv1Luid
    {
        public int Count;
        public long Luid;
        public int Attr;
    }

    //static internal const int TOKEN_QUERY = 0x00000008;
    internal const int SE_PRIVILEGE_ENABLED = 0x00000002;
    //static internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020;

    internal const int TOKEN_QUERY = 0x00000008;
    internal const int TOKEN_DUPLICATE = 0x0002;
    internal const int TOKEN_ASSIGN_PRIMARY = 0x0001;

    #endregion

    [STAThread]
    static void Main(string[] args)
    {
        string username, domain, password, applicationName;
        username = args[2];
        domain = args[1];
        password = args[3];
        applicationName = @args[0];

        IntPtr token = IntPtr.Zero;
        IntPtr primaryToken = IntPtr.Zero;
        try
        {
            bool result = false;

            result = LogonUser(username, domain, password, (int)LOGON_TYPE.LOGON32_LOGON_NETWORK, (int)LOGON_PROVIDER.LOGON32_PROVIDER_DEFAULT, out token);
            if (!result)
            {
                int winError = Marshal.GetLastWin32Error();
            }

            string commandLine = null;

            #region security attributes
            SECURITY_ATTRIBUTES processAttributes = new SECURITY_ATTRIBUTES();

            SECURITY_DESCRIPTOR sd = new SECURITY_DESCRIPTOR();
            IntPtr ptr = Marshal.AllocCoTaskMem(Marshal.SizeOf(sd));
            Marshal.StructureToPtr(sd, ptr, false);
            InitializeSecurityDescriptor(ptr, SECURITY_DESCRIPTOR_REVISION);
            sd = (SECURITY_DESCRIPTOR)Marshal.PtrToStructure(ptr, typeof(SECURITY_DESCRIPTOR));

            result = SetSecurityDescriptorDacl(ref sd, true, IntPtr.Zero, false);
            if (!result)
            {
                int winError = Marshal.GetLastWin32Error();
            }

            primaryToken = new IntPtr();
            result = DuplicateTokenEx(token, 0, ref processAttributes, SECURITY_IMPERSONATION_LEVEL.SecurityImpersonation, TOKEN_TYPE.TokenPrimary, out primaryToken);
            if (!result)
            {
                int winError = Marshal.GetLastWin32Error();
            }
            processAttributes.SecurityDescriptor = ptr;
            processAttributes.Length = (uint)Marshal.SizeOf(sd);
            processAttributes.InheritHandle = true;
            #endregion

            SECURITY_ATTRIBUTES threadAttributes = new SECURITY_ATTRIBUTES();
            threadAttributes.SecurityDescriptor = IntPtr.Zero;
            threadAttributes.Length = 0;
            threadAttributes.InheritHandle = false;

            bool inheritHandles = true;
            //CreationFlags creationFlags = CreationFlags.CREATE_DEFAULT_ERROR_MODE;
            IntPtr environment = IntPtr.Zero;
            string currentDirectory = currdir;

            STARTUPINFO startupInfo = new STARTUPINFO();
            startupInfo.Desktop = "";

            PROCESS_INFORMATION processInformation;

            result = CreateProcessAsUser(primaryToken, applicationName, commandLine, ref processAttributes, ref threadAttributes, inheritHandles, 16, environment, currentDirectory, ref startupInfo, out processInformation);
            if (!result)
            {
                int winError = Marshal.GetLastWin32Error();
                File.AppendAllText(logfile, DateTime.Now.ToLongTimeString() + " " + winError + Environment.NewLine);
            }
        }
        catch
        {
            int winError = Marshal.GetLastWin32Error();
            File.AppendAllText(logfile, DateTime.Now.ToLongTimeString() + " " + winError + Environment.NewLine);
        }
        finally
        {
            if (token != IntPtr.Zero)
            {
                int x = CloseHandle(token);
                if (x == 0)
                    throw new Win32Exception(Marshal.GetLastWin32Error());
                x = CloseHandle(primaryToken);
                if (x == 0)
                    throw new Win32Exception(Marshal.GetLastWin32Error());
            }
        }
    }

The basic procedure is:

Log the user on
convert the given token into a primary token
Using this token, execute the process
Close the handle when finished.

This is development code fresh from my machine and no way near ready for use in production environments. The code here is still buggy - For starters: I'm not sure whether the handles are closed at the right point, and there's a few interop functions defined above that aren't required. The separate starter process also really annoys me. Ideally I'd like all this Job stuff wrapped up in an assembly for use from our API as well as this service. If someone has any suggestions here, they'd be appreciated.

R – Error when impersonating a user in .NET in a scheduled task

I have since resolved this, the problem is that it doesnt have access to the desktop of the user the scheduled task runs as, so it fails. Administrators seem to be able to have this access.

The way I got round it was to have the user the task runs as perpetually logged on to the box, so access to the desktop is always available, and this works OK. Ugly I know!

Best Answer

Related Solutions

C# – Using Process.Start() to start a process as a different user from within a Windows Service

R – Error when impersonating a user in .NET in a scheduled task

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