1/* $NetBSD: kern_ssp.c,v 1.7 2016/12/06 02:55:42 christos Exp $ */ 2 3/*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#include <sys/cdefs.h> 30__KERNEL_RCSID(0, "$NetBSD: kern_ssp.c,v 1.7 2016/12/06 02:55:42 christos Exp $"); 31 32#include <sys/param.h> 33#include <sys/systm.h> 34#include <sys/intr.h> 35#include <sys/cprng.h> 36 37#if defined(__SSP__) || defined(__SSP_ALL__) 38# ifdef _RUMPKERNEL 39__weak_alias(__stack_chk_guard, stack_chk_guard) 40__weak_alias(__stack_chk_fail, stack_chk_fail) 41# define SSP_STATIC static __used 42# else 43# define stack_chk_guard __stack_chk_guard 44# define stack_chk_fail __stack_chk_fail 45# define SSP_STATIC 46#endif 47 48SSP_STATIC long stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0,}; 49SSP_STATIC void stack_chk_fail(void); 50 51SSP_STATIC void 52stack_chk_fail(void) 53{ 54 panic("stack overflow detected; terminated"); 55} 56 57void 58ssp_init(void) 59{ 60 int s; 61 62 aprint_debug("Initializing SSP: "); 63 /* 64 * We initialize ssp here carefully: 65 * 1. after we got some entropy 66 * 2. without calling a function 67 */ 68 size_t i; 69 long guard[__arraycount(stack_chk_guard)]; 70 71 cprng_fast(guard, sizeof(guard)); 72 s = splhigh(); 73 for (i = 0; i < __arraycount(guard); i++) 74 stack_chk_guard[i] = guard[i]; 75 splx(s); 76 for (i = 0; i < __arraycount(guard); i++) 77 aprint_debug("%lx ", guard[i]); 78 aprint_debug("\n"); 79} 80#else 81void 82ssp_init(void) 83{ 84} 85#endif 86