glibc/sysdeps/x86/tst-cet-legacy-9.c
H.J. Lu 04dff6fc0d x86: Properly set usable CET feature bits [BZ #26625]
commit 94cd37ebb2
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Sep 16 05:27:32 2020 -0700

    x86: Use HAS_CPU_FEATURE with IBT and SHSTK [BZ #26625]

broke

GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK

since it can no longer disable IBT nor SHSTK.  Handle IBT and SHSTK with:

1. Revert commit 94cd37ebb2.
2. Clears the usable CET feature bits if kernel doesn't support CET.
3. Add GLIBC_TUNABLES tests without dlopen.
4. Add tests to verify that CPU_FEATURE_USABLE on IBT and SHSTK matches
_get_ssp.
5. Update GLIBC_TUNABLES tests with dlopen to verify that CET is disabled
with GLIBC_TUNABLES.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-01-29 03:58:11 -08:00

42 lines
1.4 KiB
C

/* Check CET compatibility with legacy JIT engine via GLIBC_TUNABLES.
Copyright (C) 2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <support/test-driver.h>
#include <support/xunistd.h>
/* Check that mmapped legacy code won't trigger segfault with
-fcf-protection and GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK. */
static int
do_test (void)
{
void (*funcp) (void);
funcp = xmmap (NULL, 0x1000, PROT_EXEC | PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1);
printf ("mmap = %p\n", funcp);
/* Write RET instruction. */
*(char *) funcp = 0xc3;
funcp ();
return EXIT_SUCCESS;
}
#include <support/test-driver.c>