d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

NetBSD commit log:

Browse Source 
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
This commit is contained in:
Jeremie Le Hen 2015-06-14 07:47:18 +00:00
parent 78afdce6af
commit b7c4ed65cc
1 changed files with 5 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
lib/libc/sys/stack_protector.c
View File

@ -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;