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glibc/sysdeps/pthread/tst-stack2.c
Adhemerval Zanella 0c34259423 nptl: Fix pthread_getattr_np when modules with execstack are allowed (BZ 32897)
The BZ 32653 fix (12a497c716) kept the
stack pointer zeroing from make_main_stack_executable on
_dl_make_stack_executable.  However, previously the 'stack_endp'
pointed to temporary variable created before the call of
_dl_map_object_from_fd; while now we use the __libc_stack_end
directly.

Since pthread_getattr_np relies on correct __libc_stack_end, if
_dl_make_stack_executable is called (for instance, when
glibc.rtld.execstack=2 is set) __libc_stack_end will be set to zero,
and the call will always fail.

The __libc_stack_end zero was used a mitigation hardening, but since
52a01100ad it is used solely on
pthread_getattr_np code.  So there is no point in zeroing anymore.

Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Sam James <sam@gentoo.org>
2025-04-28 10:13:46 -03:00

48 lines
1.4 KiB
C

/* Check if pthread_getattr_np works within modules with non-exectuble
stacks (BZ 32897).
Copyright (C) 2025 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 <pthread.h>
#include <stdbool.h>
#include <support/xdlfcn.h>
#include <support/check.h>
static int
do_test (void)
{
{
pthread_t me = pthread_self ();
pthread_attr_t attr;
TEST_COMPARE (pthread_getattr_np (me, &attr), 0);
}
void *h = xdlopen ("tst-stack2-mod.so", RTLD_NOW);
bool *init_result = xdlsym (h, "init_result");
TEST_COMPARE (*init_result, true);
int (*mod_func)(void) = xdlsym (h, "mod_func");
TEST_COMPARE (mod_func (), 0);
xdlclose (h);
return 0;
}
#include <support/test-driver.c>