How to launch an Universal App as another user with WinAPI? - c

Question

How can I launch an Universal App as another user using CreateProcessWithLogonW()? I cannot get it to launch using C:\\Windows\\System32\\cmd.exe /c start skype: even though start skype: does launch in the terminal.
#include <stdio.h>
#include <windows.h>
#include <lmcons.h>
int main(void)
{
PROCESS_INFORMATION pi = { 0 };
STARTUPINFOW si = { 0 };
si.cb = sizeof(STARTUPINFOW);
/*
not working:
L"C:\\Windows\\System32\\cmd.exe /c start skype" error: "The filename, directory name, or volume label syntax is incorrect."
L"C:\\Windows\\System32\\cmd.exe /c start skype:" no error but a pop-up with text: "You'll need a new app to open this"
*/
wchar_t lpCommandLine[] = L"C:\\Windows\\System32\\cmd.exe /c start skype:"; // lpCommandLine must be writable memory
if (!CreateProcessWithLogonW(L"username", L".", L"password", LOGON_WITH_PROFILE, NULL, lpCommandLine, 0, NULL, NULL, &si, &pi))
{
printf("GetLastError(): %i\n", GetLastError());
char buf[UNLEN + 1] = { 0 };
FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&buf, sizeof(buf), NULL);
puts(buf);
return 1;
}
else
{
// do stuff only while skype is running
puts("skype is running.");
if (WaitForSingleObject(pi.hProcess, INFINITE) == WAIT_FAILED)
puts("WaitForSingleObject() failed");
// do stuff only after skype exits
puts("skype is NOT running.");
}
return 0;
}

Answer 1

This is impossible. No matter what user the UWP app is run under, it will always run under a sandboxed AppContainer user that is different for every user session. You can't run a UWP app as another user using the Win32 api.

Answer 2

This is possible depending on what you mean by different user. For example, in our product we have a windows service which runs under 'Local System' account and from this we are able to launch a UWP app in the currently logged on user account. For this, we have used CreateProcessAsUser to launch a process in the logged on user account with command to open the protocol supported by the UWP app. Sample code :
string uwpAppLaunchCmdLine = string.Format("/c start {0}", PROTOCOL_SUPPORTED_BY_UWP_APP);
int processId;
IntPtr hErrorReadOut = IntPtr.Zero;
ProcessMetadata processMetadata;
if (!StartAsCurrentUser("cmd.exe", false, out processId,out processMetadata, coreAppLaunchCmdLine))
{
//Failed to launch
}
else
{
//success!
}