1 /* $NetBSD: kern_ssp.c,v 1.5 2010/02/01 16:14:58 njoly 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 1.5 2010/02/01 16:14:58 njoly Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/intr.h> 35 36 #if defined(__SSP__) || defined(__SSP_ALL__) 37 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 38 void __stack_chk_fail(void); 39 40 void 41 __stack_chk_fail(void) 42 { 43 panic("stack overflow detected; terminated"); 44 } 45 46 void 47 ssp_init(void) 48 { 49 int s; 50 51 aprint_debug("Initializing SSP: "); 52 /* 53 * We initialize ssp here carefully: 54 * 1. after we got some entropy 55 * 2. without calling a function 56 */ 57 size_t i; 58 long guard[__arraycount(__stack_chk_guard)]; 59 60 arc4randbytes(guard, sizeof(guard)); 61 s = splhigh(); 62 for (i = 0; i < __arraycount(guard); i++) 63 __stack_chk_guard[i] = guard[i]; 64 splx(s); 65 for (i = 0; i < __arraycount(guard); i++) 66 aprint_debug("%lx ", guard[i]); 67 aprint_debug("\n"); 68 } 69 #else 70 void 71 ssp_init(void) 72 { 73 } 74 #endif 75