/*
 * Demonstrates brk area crashing into other segments when run
 * under NX-emulation kernel patch.
 *
 * Copyright (C) 2010, Canonical, Ltd.
 * Author: Kees Cook <kees@ubuntu.com>
 * License: GPLv3
 *
 * gcc explode.c -fPIE -pie -o explode
 *
 */
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <stdint.h>
#include <stddef.h>
#include <inttypes.h>

// The larger this size, the faster a collision can be found.
//#define SIZE (32*1024)
#define SIZE (1)

int main(int argc, char * argv[])
{
    char cmd[80];
    int i;

    void * start = sbrk(0);
    void * end = (void*)((uintptr_t)start + SIZE);

    snprintf(cmd,sizeof(cmd),"cat /proc/%d/maps", getpid());

    printf("%p\n", start);

    if ((uintptr_t)sbrk(SIZE) == -1) {
        printf("Failed to use brk area at %p - %p\n", start, end);
        system(cmd);
        return 1;
    }

    // try again
    execv(argv[0],argv);
    perror("execv");
    return 2;
}