GetTokenInformation, TOKEN_OWNER, and LookupAccountSidA - winapi

Question

I am trying to use these features to get the username running the process. Here is the code:
#include <windows.h>
#include <psapi.h>
using namespace std;
int main()
{
HANDLE hProcess = GetCurrentProcess();
HANDLE hToken;
OpenProcessToken(hProcess, TOKEN_QUERY, &hToken);
DWORD len = 0;
GetTokenInformation(hToken, TokenOwner, NULL, 0, &len);
PTOKEN_OWNER to = (PTOKEN_OWNER)LocalAlloc(LPTR, len);
GetTokenInformation(hToken, TokenOwner, (LPVOID)&to, len, &len);
char nameUser[50];
DWORD nameUserSize = sizeof(nameUser);
SID_NAME_USE snu;
cout << "work";
LookupAccountSidA(NULL, to->Owner, nameUser, &nameUserSize, NULL, NULL, &snu);
cout << "not work";
cout << nameUser << endl;
LocalFree(to);
CloseHandle(hToken);
CloseHandle(hProcess);
return 0;
}
I have all the breaks at the moment where LookupAccountSidA() is called. But I suspect the problem is due to the fact that I was wrong with the arguments to this function, or I am wrong to create a structure TOKEN_OWNER. The second option is more likely, since I do not understand how memory is allocated here.
I took an example from MSDN and rewrote it to my needs, but nothing works. Here are some examples from MSDN:
Getting the Logon SID in C++
Searching for a SID in an Access Token in C++
P.S. For russian-speaking:
https://ru.stackoverflow.com/questions/519602/

Answer 1

Your second call to GetTokenInformation() is passing the wrong memory address in the 3rd parameter. You are passing the memory address of the to variable itself, so you are asking GetTokenInformation() to write into surrounding stack space. You need to pass the memory address that the variable is pointing at instead (the allocated TOKEN_OWNER structure), so get rid of the & operator (and the type-cast, which is not necessary):
GetTokenInformation(hToken, TokenOwner, to, len, &len);
You are also not doing any error handling at all, so you don't know if memory is being allocated successfully, or if any API function are failing.
Try this instead:
#include <windows.h>
#include <psapi.h>
using namespace std;
int main()
{
DWORD dwError;
HANDLE hToken;
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &hToken))
{
dwError = GetLastError();
cerr << "OpenProcessToken failed, error " << dwError;
return 0;
}
DWORD len = 0;
if (!GetTokenInformation(hToken, TokenOwner, NULL, 0, &len))
{
dwError = GetLastError();
if (dwError != ERROR_INSUFFICIENT_BUFFER)
{
cerr << "GetTokenInformation failed, error " << dwError;
CloseHandle(hToken);
return 0;
}
}
PTOKEN_OWNER to = (PTOKEN_OWNER) LocalAlloc(LPTR, len);
if (!to)
{
dwError = GetLastError();
cerr << "LocalAlloc failed, error " << dwError;
CloseHandle(hToken);
return 0;
}
if (!GetTokenInformation(hToken, TokenOwner, to, len, &len))
{
dwError = GetLastError();
cerr << "GetTokenInformation failed, error " << dwError;
LocalFree(to);
CloseHandle(hToken);
return 0;
}
char nameUser[256] = {0};
char domainName[256] = {0};
DWORD nameUserLen = 256;
DWORD domainNameLen = 256;
SID_NAME_USE snu;
if (!LookupAccountSidA(NULL, to->Owner, nameUser, &nameUserLen, domainName, &domainNameLen, &snu))
{
dwError = GetLastError();
cerr << "LookupAccountSid failed, error " << dwError;
LocalFree(to);
CloseHandle(hToken);
return 0;
}
cout << domainName << '/' << nameUser << endl;
LocalFree(to);
CloseHandle(hToken);
return 0;
}