Buffer overflow sample program

// A C program to demonstrate buffer overflow
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{

// Reserve 5 byte of buffer plus the terminating NULL.
// should allocate 8 bytes = 2 double words,
// To overflow, need more than 8 bytes...
char buffer[5]; // If more than 8 characters input
// by user, there will be access
// violation, segmentation fault

// a prompt how to execute the program...
if (argc < 4)
{
printf("strcpy() NOT executed....\n");
printf("Syntax: %s <characters>\n", argv[0]);
exit(0);
}

// copy the user input to mybuffer, without any
// bound checking a secure version is srtcpy_s()
strcpy(buffer, argv[1]);
printf("buffer content= %s\n", buffer);

// you may want to try strcpy_s()
printf("strcpy() executed...\n");

return 0;
}

Tips: when you change the value of argc Greater than the value given 5 then the bufferoverflow message will be the output.