160484Sobrien/* $NetBSD: exec_prot_support.c,v 1.1 2011/07/18 23:16:09 jym Exp $ */ 260484Sobrien 360484Sobrien/*- 460484Sobrien * Copyright (c) 2011 The NetBSD Foundation, Inc. 560484Sobrien * All rights reserved. 660484Sobrien * 760484Sobrien * This code is derived from software contributed to The NetBSD Foundation 860484Sobrien * by Jean-Yves Migeon. 960484Sobrien * 1060484Sobrien * Redistribution and use in source and binary forms, with or without 1160484Sobrien * modification, are permitted provided that the following conditions 1260484Sobrien * are met: 1360484Sobrien * 1. Redistributions of source code must retain the above copyright 1460484Sobrien * notice, this list of conditions and the following disclaimer. 1560484Sobrien * 2. Redistributions in binary form must reproduce the above copyright 1660484Sobrien * notice, this list of conditions and the following disclaimer in the 1760484Sobrien * documentation and/or other materials provided with the distribution. 1860484Sobrien * 1960484Sobrien * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 2060484Sobrien * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 2160484Sobrien * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 2260484Sobrien * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 2360484Sobrien * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 2460484Sobrien * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 2560484Sobrien * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 2660484Sobrien * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 2760484Sobrien * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 2860484Sobrien * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 2960484Sobrien * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <sys/cdefs.h> 33__RCSID("$NetBSD: exec_prot_support.c,v 1.1 2011/07/18 23:16:09 jym Exp $"); 34 35#include <stdlib.h> 36#include <sys/sysctl.h> 37 38#include "../../common/exec_prot.h" 39 40/* 41 * Support for executable space protection has always been erratic under i386. 42 * Originally IA-32 can't do per-page execute permission, so it is 43 * implemented using different executable segments for %cs (code segment). 44 * This only allows coarse grained protection, especially when memory starts 45 * being fragmented. 46 * Later, PAE was introduced together with a NX/XD bit in the page table 47 * entry to offer per-page permission. 48 */ 49int 50exec_prot_support(void) 51{ 52 int pae; 53 size_t pae_len = sizeof(pae); 54 55 if (sysctlbyname("machdep.pae", &pae, &pae_len, NULL, 0) == -1) 56 return PARTIAL_XP; 57 58 if (pae == 1) { 59 if (system("cpuctl identify 0 | grep -q NOX") == 0 || 60 system("cpuctl identify 0 | grep -q XD") == 0) 61 return PERPAGE_XP; 62 } 63 64 return PARTIAL_XP; 65} 66