src/util-pages.c

   1 /* Copyright (C) 2016 Open Information Security Foundation
   2  *
   3  * You can copy, redistribute or modify this Program under the terms of
   4  * the GNU General Public License version 2 as published by the Free
   5  * Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * version 2 along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  15  * 02110-1301, USA.
  16  */
  17
  18 /**
  19  * \file
  20  *
  21  * \author Victor Julien <victor@inliniac.net>
  22  *
  23  * Page util functions
  24  */
  25
  26 #include "suricata-common.h"
  27 #include "util-pages.h"
  28
  29 #ifndef HAVE_PAGESUPPORTSRWX_AS_MACRO
  30
  31 /** \brief check if OS allows for RWX pages
  32  *
  33  *  Some OS' disallow RWX pages for security reasons. This function mmaps
  34  *  some memory RW and then tries to turn it into RWX. If this fails we
  35  *  assume that the OS doesn't allow for this.
  36  *
  37  *  Thanks to Shawn Webb from HardenedBSD for the suggestion.
  38  *
  39  *  \retval 1 RWX supported
  40  *  \retval 0 not supported
  41  */
  42 int PageSupportsRWX(void)
  43 {
  44     int retval = 1;
  45     void *ptr;
  46     ptr = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED, -1, 0);
  47     if (ptr != MAP_FAILED) {
  48         if (mprotect(ptr, getpagesize(), PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
  49             SCLogConfig("RWX pages denied by OS");
  50             retval = 0;
  51         }
  52         munmap(ptr, getpagesize());
  53     }
  54     return retval;
  55 }
  56 #endif /* HAVE_PAGESUPPORTSRWX_AS_MACRO */
  57