Develop Reference

How do I change system time from a non elevated c# program

I need your help again :)
What I want to do:
I have a c# program which runs with normal user permissions - those can't be raised - and I want to change the system date (not time) from that program.
[EDIT] To be a bit more specific: I do have administrator credentials which could be embedded to the program (yikes, I know), but I want to avoid an UAC prompt.
When I launch cmd from outside Visual Studio and try to change the date, it fails with "missing client permission" (roughly translated from German). When I launch cmd as administrator, confirm the UAC prompt the same command succeeds.
I am writing from home, so I cant provide running code at the moment. But all my tries did compile and run without error but the date wasn't changed.
What I've tried:
Created a Process instance, applied admin credentials to ProcessStartInfo, set the FileName to c:\windows\system32\cmd.exe and the argument to /C date {thedate}. I redirected StandardOutput and StandardError and after execution StandardError contains the same message as stated above: "missing client permission"
I've modified this example MSDN: WindowsIdentity.Impersonate using PInvoke with AdvAPI32.LogonUser to raise permissions and Kernel32.SetSystemTime to change the system time. AdvAPI32.LogonUser succeeds and WindowsIdentity.GetCurrent().Name returns the admin name, but calling Kernel32.SetSystemTime fails with "missing client permission".
I've tried opening the current process AdvApi32.OpenCurrentProcess and adjusting the permissions using AdvApi32.AdjustTokenPrivileges following this example StackOverflow: Change system time programmaticaly using datetimepeaker and the code runs totally fine but Kernel32.SetSystemTime fails...
[EDIT] Solution:
I ended up writing a small program with an embedded app.manifest that requests administrator privilegs. This app is called from the main program so this can still be run by a normal user.

It is not possible to change the privileges of the process, once it's started. The original process has to start another process with elevated privileges. This second process can actually be the same .exe file, but with a command parameter that tells the process to do some small stuff and exit immediately.
To start a process with elevated privileges use Process.Start, but with .Verb = "runas", as described in another question. This will of course cause UAC prompt to pop up, if it's enabled on the machine. At least one UAC prompt has to be shown, because UAC prompt is the whole point if this defense mechanism.
If you want to reduce many UAC prompts to just one then you can set the original app to be started as administrator (UAC prompt shows when original process starts) and have just one process. Or have some interprocess communication between original process and elevated process, so that elevated process is started only once and made to finish when original process ends. In the second case UAC prompt shows the first time it's needed.

Can I ask why you are needing to change the system time from an unprivileged application?
If it is to influence other applications then you will need admin privilege since date time is such a vital system function to many other applications. However if you are just needing to adjust the date in your application only then I would suggest creating your own date/time provider that can return the date offset to the date that you desire in your application.
For example.
public DateTime GetDateWithOffset(int daysToOffset)
{
return DateTime.UtcNow.AddDays(daysToOffset);
}

execute run as command and enter password in c#

I am trying to execute
runas /netonly /user:domain\username "C:\Users\user\Documents\Visual Studio 2015\Projects\samplePACE\samplePACE\bin\Debug\samplePACE.exe
brown"
samplePACE.exe is the Application name and brown is the argument.
It will ask for a password.
I have to enter and then the application gets executed.
I need to perform the above two operations using C#.
Thanks.

You want to use use the Process class to run the process. Scroll to the bottom of that page for an example on how it is used.
To elevate (aka run as Administrator), you will need to use the 'runas' verb. See this SO post for more info: Elevating process privilege programmatically?

plink process doesn't end if calling user isn't logged in

I'm calling plink from C# code which is running as a certain Windows user. I call plink like
plink.exe user#hostname -pw password commands
Usually the plink process ends immediately after the commands have been run, but when the user which the code runs under is not logged into Windows, the plink process doesn't end.
As all these zombie processes build up there comes a point when new processes can't be created anymore...
Any idea why this would be happening?

This could be because the first time you connect to a new server PuTTY registers a host key in the registry, under the currently logged in user (under HKEY_CURRENT_USER). With that user not being logged in, that portion of the registry may be inaccessible.
Try moving the key to HKEY_LOCAL_SYSTEM. That process is described in detail here:
http://xxlinxx.wordpress.com/2009/03/23/set-up-an-ssh-tunnel-as-a-windows-service-using-putty-plink/
There is a final note on that page that could prove to be important too depending on your specific use case:
"Also, if the Windows SYSTEM user cannot see the host key for SSH connection, the tunnel cannot be established."
PS: There is another page here here that talks about moving the cert to HKEY_USERS.DEFAULT

c# interactiveProcessRunner

Can someone tell me what the InteractiveProcessRunner is for? Is it identical to Process.Start?
Here is the class.
And here an example :
InteractiveProcessRunner runner =
new InteractiveProcessRunner(notepad.exe,hSessionToken);
THX

Whit this class you can run a process with the complete environment of the user active: if you call this code from a service, you should find the user mapped resources, the desktop and all the resources that are available when the user is loggen on interactively even if launched from a service ie not logged interactively.

The source code to which your link leads referes to this article: http://asprosys.blogspot.com/2009/03/perils-and-pitfalls-of-launching.html which explains the motivation behind it.
Summary: You can't really use Process.Start() when you want to start a new process as certain user from a windows service. The InteractiveProcessRunner lets you do this (supposedly, never used it so I can't verify it). So it's not the same as Process.Start() - it uses a different Windows API.

Login with Admin user to some domain and copy files client machines with C#

I have got a project that can copy files to another client's desktops in my domain.There is 300+ client machine.But there is a problem.When i run this project in a non admin user account in my domain.It cant copy files getting error about Access Denied , user restrictions.I wanna do this program like this , in non admin user account when user start to copy files ;
first my program will get admin access by loggin in my admin user accoun to domain than will copy files.Than logout.How can i do this ? I wanna do this with C#.

I had a similar problem: Production needed to run one of my programs that processes files on a location on the network where they don't have any access.
I ended up using Impersonation, which allowed me to run the file processing thread under a set of credentials set at runtime by my program.
In AD I created a special user account with all required permissions for exclusive use by this program.
I know it’s not at all secure, but it works and the odds that it would even occur to someone to hack my program to get these credentials is remote.
Anyway, look into Impersonation I found these resources helpful:
Safely Impersonating Another User
Brian Low's ImpersonationHelper class
-Jay

You can switch privileges when starting the program from itself or from another program. You can do this with two programs, one that runs as the user account and then launches your privileged application. (or launch itself with a different command line to indicate the different run-mode.)
To launch a program in C# as a different user, do this,
// Create a secure version of the password
SecureString pass = new SecureString();
foreach ( char c in _pass.Text )
{
pass.AppendChar( c );
}
Process process = Process.Start( "PrivilegedProgram.exe", _arguments, _user.Text, pass, _domain.Text );

you need to change the thread to the context of an admin user. How you do that in a secure way is the challenge. This sounds like a quick utility program where the security may not be a big deal, however. Just change the admin's password once the utility has been run.