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1bdda52fe9
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>
99 lines
2.8 KiB
C
99 lines
2.8 KiB
C
/* Initialization code run first thing by the ELF startup code. Common version
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Copyright (C) 1995-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <ctype.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sysdep.h>
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#include <fpu_control.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#include <libc-internal.h>
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#include <ldsodefs.h>
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/* Set nonzero if we have to be prepared for more than one libc being
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used in the process. Safe assumption if initializer never runs. */
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int __libc_multiple_libcs attribute_hidden = 1;
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/* Remember the command line argument and enviroment contents for
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later calls of initializers for dynamic libraries. */
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int __libc_argc attribute_hidden;
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char **__libc_argv attribute_hidden;
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void
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__libc_init_first (int argc, char **argv, char **envp)
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{
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#ifdef SHARED
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/* For DSOs we do not need __libc_init_first but instead _init. */
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}
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void
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attribute_hidden
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_init (int argc, char **argv, char **envp)
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{
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#endif
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__libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
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/* Make sure we don't initialize twice. */
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if (!__libc_multiple_libcs)
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{
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/* Set the FPU control word to the proper default value if the
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kernel would use a different value. */
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if (__fpu_control != GLRO(dl_fpu_control))
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__setfpucw (__fpu_control);
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}
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/* Save the command-line arguments. */
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__libc_argc = argc;
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__libc_argv = argv;
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__environ = envp;
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#ifndef SHARED
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/* First the initialization which normally would be done by the
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dynamic linker. */
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_dl_non_dynamic_init ();
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#endif
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__init_misc (argc, argv, envp);
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/* Initialize ctype data. */
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__ctype_init ();
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#if defined SHARED && !defined NO_CTORS_DTORS_SECTIONS
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__libc_global_ctors ();
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#endif
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}
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/* This function is defined here so that if this file ever gets into
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ld.so we will get a link error. Having this file silently included
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in ld.so causes disaster, because the _init definition above will
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cause ld.so to gain an init function, which is not a cool thing. */
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extern void _dl_start (void) __attribute__ ((noreturn));
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void
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_dl_start (void)
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{
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abort ();
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}
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