Question

I got two console processes that second one is created by first one using the API below:

BOOL WINAPI CreateProcess(
  __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
);

Now I wonder that if I pass a pointer to a part of memory of the first process, via IpCommandLine to the second process which is called by first process, will reading the memory to which that pointer points, by the second process definitely cause an access violation error or is it subject to value of some parameter of that API?
If I can’t use this API alone for my purpose, what method do you propose for the access ?

Answer 1

You can access this memory using ReadProcessMemory/WriteProcessMemory API. Another process needs to know memory address and handle of the process to access its memory.