sys/kern/stack_protector.c

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