Author: jlh
Date: Sun Jun 14 07:47:18 2015
New Revision: 284377
URL: https://svnweb.freebsd.org/changeset/base/284377
Log:
NetBSD commit log:
Use a constant array for the MIB. Newer LLVM decided that mib[] warranted
stack protections, with the obvious crash after the setup was done.
As a positive side effect, code size shrinks a bit.
I'm not sure why this hasn't bitten us yes, but it is certainly possible and
there are no real drawbacks to this change anyway.
Submitted by: pfg
Obtained from: NetBSD
MFC after: 1 week
Modified:
head/lib/libc/sys/stack_protector.c
Modified: head/lib/libc/sys/stack_protector.c
==============================================================================
--- head/lib/libc/sys/stack_protector.c Sun Jun 14 05:23:39 2015
(r284376)
+++ head/lib/libc/sys/stack_protector.c Sun Jun 14 07:47:18 2015
(r284377)
@@ -41,8 +41,8 @@ __FBSDID("$FreeBSD$");
#include <unistd.h>
#include "libc_private.h"
-extern int __sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
- void *newp, size_t newlen);
+extern int __sysctl(const int *name, u_int namelen, void *oldp,
+ size_t *oldlenp, void *newp, size_t newlen);
long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
static void __guard_setup(void) __attribute__((__constructor__, __used__));
@@ -54,7 +54,7 @@ void __chk_fail(void);
static void
__guard_setup(void)
{
- int mib[2];
+ static const int mib[2] = { CTL_KERN, KERN_ARND };
size_t len;
int error;
@@ -65,12 +65,9 @@ __guard_setup(void)
if (error == 0 && __stack_chk_guard[0] != 0)
return;
- mib[0] = CTL_KERN;
- mib[1] = KERN_ARND;
-
len = sizeof(__stack_chk_guard);
- if (__sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
- len != sizeof(__stack_chk_guard)) {
+ if (__sysctl(mib, nitems(mib), __stack_chk_guard, &len, NULL, 0) ==
+ -1 || len != sizeof(__stack_chk_guard)) {
/* If sysctl was unsuccessful, use the "terminator canary". */
((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
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