/*
 * eco.c
 *
 * Mike Smith
 *
 * h4cked by Jason Gao '10
 *
 * This program is an UNSAFE implementation of our echo program.  It
 * assumes that all strings on the command line are smaller than 4
 * characters in length.  Obviously, this is a bad assumption, and
 * thus we can use it to demonstrate the simplicity of a static buffer
 * overrun attack.
 * 
 * If you run the program with the following perl-formated input, it
 * will return to the function gotcha instead of main.
 *
 * "1234" . "\xb8\xf5\xff\xbf" . "\xb4\x84\x04\x08";
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_BUF_SIZE 4


void
gotcha()
{
    printf("\nGotcha!\n");
    exit(1);  /* required because we destroy the caller's base pointer */
}


void
echo_arg(const char s[])
{
    char buf[MAX_BUF_SIZE];
    strcpy(buf, s);
    printf("%s ", buf);
}


int
main(int argc, char * argv[])
{
    int i;
    for (i = 1; i < argc; i++)
    	echo_arg(argv[i]);
    printf("\n");

    return 0;
}