xref: /f-stack/freebsd/kern/stack_protector.c (revision a9643ea8)
1*a9643ea8Slogwang #include <sys/cdefs.h>
2*a9643ea8Slogwang __FBSDID("$FreeBSD$");
3*a9643ea8Slogwang 
4*a9643ea8Slogwang #include <sys/types.h>
5*a9643ea8Slogwang #include <sys/param.h>
6*a9643ea8Slogwang #include <sys/kernel.h>
7*a9643ea8Slogwang #include <sys/systm.h>
8*a9643ea8Slogwang #include <sys/libkern.h>
9*a9643ea8Slogwang 
10*a9643ea8Slogwang long __stack_chk_guard[8] = {};
11*a9643ea8Slogwang void __stack_chk_fail(void);
12*a9643ea8Slogwang 
13*a9643ea8Slogwang void
__stack_chk_fail(void)14*a9643ea8Slogwang __stack_chk_fail(void)
15*a9643ea8Slogwang {
16*a9643ea8Slogwang 
17*a9643ea8Slogwang 	panic("stack overflow detected; backtrace may be corrupted");
18*a9643ea8Slogwang }
19*a9643ea8Slogwang 
20*a9643ea8Slogwang static void
__stack_chk_init(void * dummy __unused)21*a9643ea8Slogwang __stack_chk_init(void *dummy __unused)
22*a9643ea8Slogwang {
23*a9643ea8Slogwang 	size_t i;
24*a9643ea8Slogwang 	long guard[nitems(__stack_chk_guard)];
25*a9643ea8Slogwang 
26*a9643ea8Slogwang 	arc4rand(guard, sizeof(guard), 0);
27*a9643ea8Slogwang 	for (i = 0; i < nitems(guard); i++)
28*a9643ea8Slogwang 		__stack_chk_guard[i] = guard[i];
29*a9643ea8Slogwang }
30*a9643ea8Slogwang SYSINIT(stack_chk, SI_SUB_RANDOM, SI_ORDER_ANY, __stack_chk_init, NULL);
31