xref: /freebsd/sys/kern/stack_protector.c (revision e64585bdc269419485641134ed45d329363171e6)
1042df2e2SRuslan Ermilov #include <sys/cdefs.h>
2042df2e2SRuslan Ermilov __FBSDID("$FreeBSD$");
3042df2e2SRuslan Ermilov 
4042df2e2SRuslan Ermilov #include <sys/types.h>
5042df2e2SRuslan Ermilov #include <sys/param.h>
6042df2e2SRuslan Ermilov #include <sys/kernel.h>
7042df2e2SRuslan Ermilov #include <sys/systm.h>
8042df2e2SRuslan Ermilov #include <sys/libkern.h>
9042df2e2SRuslan Ermilov 
10042df2e2SRuslan Ermilov long __stack_chk_guard[8] = {};
11042df2e2SRuslan Ermilov void __stack_chk_fail(void);
12042df2e2SRuslan Ermilov 
13042df2e2SRuslan Ermilov void
14042df2e2SRuslan Ermilov __stack_chk_fail(void)
15042df2e2SRuslan Ermilov {
16042df2e2SRuslan Ermilov 
17042df2e2SRuslan Ermilov 	panic("stack overflow detected; backtrace may be corrupted");
18042df2e2SRuslan Ermilov }
19042df2e2SRuslan Ermilov 
20042df2e2SRuslan Ermilov #define __arraycount(__x)	(sizeof(__x) / sizeof(__x[0]))
21042df2e2SRuslan Ermilov static void
22042df2e2SRuslan Ermilov __stack_chk_init(void *dummy __unused)
23042df2e2SRuslan Ermilov {
24042df2e2SRuslan Ermilov 	size_t i;
25042df2e2SRuslan Ermilov 	long guard[__arraycount(__stack_chk_guard)];
26042df2e2SRuslan Ermilov 
27042df2e2SRuslan Ermilov 	arc4rand(guard, sizeof(guard), 0);
28042df2e2SRuslan Ermilov 	for (i = 0; i < __arraycount(guard); i++)
29042df2e2SRuslan Ermilov 		__stack_chk_guard[i] = guard[i];
30042df2e2SRuslan Ermilov }
31e64585bdSRuslan Ermilov SYSINIT(stack_chk, SI_SUB_RANDOM, SI_ORDER_ANY, __stack_chk_init, NULL);
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