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>

1 files changed, 0 insertions, 90 deletions

diff --git a/sysdeps/unix/sysv/linux/init-first.c b/sysdeps/unix/sysv/linux/init-first.c
deleted file mode 100644
index a215a1b376..0000000000
--- a/sysdeps/unix/sysv/linux/init-first.c
+++ /dev/null
@@ -1,90 +0,0 @@
-/* vDSO internal symbols.  Linux generic version.
-   Copyright (C) 2019-2020 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
-   <http://www.gnu.org/licenses/>.  */
-
-#include <dl-vdso.h>
-#include <libc-vdso.h>
-
-/* vDSO symbol used on clock_gettime implementation.  */
-#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
-int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on clock_gettime64 implementation.  */
-#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
-int (*VDSO_SYMBOL(clock_gettime64)) (clockid_t, struct __timespec64 *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on clock_getres implementation.  */
-#ifdef HAVE_CLOCK_GETRES_VSYSCALL
-int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on gettimeofday implementation.  */
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-int (*VDSO_SYMBOL (gettimeofday)) (struct timeval *, void *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on GNU extension getcpu implementation.  */
-#ifdef HAVE_GETCPU_VSYSCALL
-long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
-   attribute_hidden;
-#endif
-/* vDSO symbol used on time implementation.  */
-#ifdef HAVE_TIME_VSYSCALL
-time_t (*VDSO_SYMBOL(time)) (time_t *) attribute_hidden;
-#endif
-
-static inline void
-__libc_vdso_platform_setup (void)
-{
-#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
-  VDSO_SYMBOL(clock_gettime)
-    = get_vdso_mangle_symbol (HAVE_CLOCK_GETTIME_VSYSCALL);
-#endif
-
-#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
-  VDSO_SYMBOL(clock_gettime64)
-    = get_vdso_mangle_symbol (HAVE_CLOCK_GETTIME64_VSYSCALL);
-#endif
-
-#ifdef HAVE_CLOCK_GETRES_VSYSCALL
-  VDSO_SYMBOL(clock_getres)
-    = get_vdso_mangle_symbol (HAVE_CLOCK_GETRES_VSYSCALL);
-#endif
-
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-  VDSO_SYMBOL(gettimeofday)
-    = get_vdso_mangle_symbol (HAVE_GETTIMEOFDAY_VSYSCALL);
-#endif
-
-#ifdef HAVE_GETCPU_VSYSCALL
-  VDSO_SYMBOL(getcpu) = get_vdso_mangle_symbol (HAVE_GETCPU_VSYSCALL);
-#endif
-
-#ifdef HAVE_TIME_VSYSCALL
-  VDSO_SYMBOL(time) = get_vdso_mangle_symbol (HAVE_TIME_VSYSCALL);
-#endif
-
-#ifdef VDSO_SETUP_ARCH
-  VDSO_SETUP_ARCH ();
-#endif
-}
-
-#define VDSO_SETUP __libc_vdso_platform_setup
-
-#include <csu/init-first.c>