stack_protector.c revision 180012
1180012Sru#include <sys/cdefs.h> 2180012Sru__FBSDID("$FreeBSD: head/sys/kern/stack_protector.c 180012 2008-06-25 21:33:28Z ru $"); 3180012Sru 4180012Sru#include <sys/types.h> 5180012Sru#include <sys/param.h> 6180012Sru#include <sys/kernel.h> 7180012Sru#include <sys/systm.h> 8180012Sru#include <sys/libkern.h> 9180012Sru 10180012Sru#if defined(__SSP__) || defined(__SSP_ALL__) 11180012Srulong __stack_chk_guard[8] = {}; 12180012Sruvoid __stack_chk_fail(void); 13180012Sru 14180012Sruvoid 15180012Sru__stack_chk_fail(void) 16180012Sru{ 17180012Sru 18180012Sru panic("stack overflow detected; backtrace may be corrupted"); 19180012Sru} 20180012Sru 21180012Sru#define __arraycount(__x) (sizeof(__x) / sizeof(__x[0])) 22180012Srustatic void 23180012Sru__stack_chk_init(void *dummy __unused) 24180012Sru{ 25180012Sru size_t i; 26180012Sru long guard[__arraycount(__stack_chk_guard)]; 27180012Sru 28180012Sru arc4rand(guard, sizeof(guard), 0); 29180012Sru for (i = 0; i < __arraycount(guard); i++) 30180012Sru __stack_chk_guard[i] = guard[i]; 31180012Sru} 32180012Sru/* SI_SUB_EVENTHANDLER is right after SI_SUB_LOCK used by arc4rand() init. */ 33180012SruSYSINIT(stack_chk, SI_SUB_EVENTHANDLER, SI_ORDER_ANY, __stack_chk_init, NULL); 34180012Sru 35180012Sru#endif 36