1 /* $NetBSD: kern_ssp.c,v 1.6 2011/11/19 22:51:25 tls 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 1.6 2011/11/19 22:51:25 tls 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 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 39 void __stack_chk_fail(void); 40 41 void 42 __stack_chk_fail(void) 43 { 44 panic("stack overflow detected; terminated"); 45 } 46 47 void 48 ssp_init(void) 49 { 50 int s; 51 52 aprint_debug("Initializing SSP: "); 53 /* 54 * We initialize ssp here carefully: 55 * 1. after we got some entropy 56 * 2. without calling a function 57 */ 58 size_t i; 59 long guard[__arraycount(__stack_chk_guard)]; 60 61 cprng_fast(guard, sizeof(guard)); 62 s = splhigh(); 63 for (i = 0; i < __arraycount(guard); i++) 64 __stack_chk_guard[i] = guard[i]; 65 splx(s); 66 for (i = 0; i < __arraycount(guard); i++) 67 aprint_debug("%lx ", guard[i]); 68 aprint_debug("\n"); 69 } 70 #else 71 void 72 ssp_init(void) 73 { 74 } 75 #endif 76