Stack corruption in C++

Question

In C++, in which way the stack may get corrupted. One way I guess is to overwriting the stack variables by accessing an array beyond its boundaries. Is there any other way t

Answer 1

Violations of the One Definition Rule can lead to stack corruption. The following example looks stupid, but I've seen it a couple of times with different libraries compiled in different configurations.

header.h

struct MyStruct
{
   int val;
#ifdef LARGEMYSTRUCT
   char padding[16];
#endif
}

file1.cpp

#define LARGEMYSTRUCT
#include "header.h"

//Here it looks like MyStruct is 20 bytes in size    

void func(MyStruct s)
{
   memset(s.padding, 0, 16); //corrupts the stack as below file2.cpp does not have LARGEMYSTRUCT declared and declares Mystruct with 4 bytes
   return; //Will probably crash here as the return pointer has been overwritten
}

file2.cpp

#include "header.h"
//Here it looks like MyStruct is only 4 bytes in size.
extern void func(MyStruct s);

void caller()
{
   MyStruct s;
   func(s); //push four bytes on to the stack
}