glibc/sysdeps/unix/sysv/linux/sysdep-vdso.h
Adhemerval Zanella 1bdda52fe9 elf: Move vDSO setup to rtld (BZ#24967)
This patch moves the vDSO setup from libc to loader code, just after
the vDSO link_map setup.  For static case the initialization
is moved to _dl_non_dynamic_init instead.

Instead of using the mangled pointer, the vDSO data is set as
attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for
static).  It is read-only even with partial relro.

It fixes BZ#24967 now that the vDSO pointer is setup earlier than
malloc interposition is called.

Also, vDSO calls should not be a problem for static dlopen as
indicated by BZ#20802.  The vDSO pointer would be zero-initialized
and the syscall will be issued instead.

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu,
powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and
sparcv9-linux-gnu.  I also run some tests on mips.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2020-01-03 11:22:07 -03:00

58 lines
2.1 KiB
C

/* vDSO common definition for Linux.
Copyright (C) 2015-2020 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/>. */
#ifndef SYSDEP_VDSO_LINUX_H
# define SYSDEP_VDSO_LINUX_H
#include <ldsodefs.h>
#ifndef INTERNAL_VSYSCALL_CALL
# define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...) \
funcptr (args)
#endif
#define INLINE_VSYSCALL(name, nr, args...) \
({ \
__label__ out; \
__label__ iserr; \
INTERNAL_SYSCALL_DECL (sc_err); \
long int sc_ret; \
\
__typeof (GLRO(dl_vdso_##name)) vdsop = GLRO(dl_vdso_##name); \
if (vdsop != NULL) \
{ \
sc_ret = INTERNAL_VSYSCALL_CALL (vdsop, sc_err, nr, ##args); \
if (!INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err)) \
goto out; \
if (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err) != ENOSYS) \
goto iserr; \
} \
\
sc_ret = INTERNAL_SYSCALL (name, sc_err, nr, ##args); \
if (INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err)) \
{ \
iserr: \
__set_errno (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err)); \
sc_ret = -1L; \
} \
out: \
sc_ret; \
})
#endif /* SYSDEP_VDSO_LINUX_H */