darling-gdb/bfd/elf32-tilegx.c
Alan Modra 5474d94f03 dynrelro section for read-only dynamic symbols copied into executable
Variables defined in shared libraries are copied into an executable's
.bss section when code in the executable is non-PIC and thus would
require dynamic text relocations to access the variable directly in
the shared library.  Recent x86 toolchains also copy variables into
the executable to gain a small speed improvement.

The problem is that if the variable was originally read-only, the copy
in .bss is writable, potentially opening a security hole.  This patch
cures that problem by putting the copy in a section that becomes
read-only after ld.so relocation, provided -z relro is in force.

The patch also fixes a microblaze linker segfault on attempting to
use dynamic bss variables.

bfd/
	PR ld/20995
	* elf-bfd.h (struct elf_link_hash_table): Add sdynrelro and
	sreldynrelro.
	(struct elf_backend_data): Add want_dynrelro.
	* elfxx-target.h (elf_backend_want_dynrelro): Define.
	(elfNN_bed): Update initializer.
	* elflink.c (_bfd_elf_create_dynamic_sections): Create
	sdynrelro and sreldynrelro sections.
	* elf32-arm.c (elf32_arm_adjust_dynamic_symbol): Place variables
	copied into the executable from read-only sections into sdynrelro.
	(elf32_arm_size_dynamic_sections): Handle sdynrelro.
	(elf32_arm_finish_dynamic_symbol): Select sreldynrelro for
	dynamic relocs in sdynrelro.
	(elf_backend_want_dynrelro): Define.
	* elf32-hppa.c (elf32_hppa_adjust_dynamic_symbol)
	(elf32_hppa_size_dynamic_sections, elf32_hppa_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf32-i386.c (elf_i386_adjust_dynamic_symbol)
	(elf_i386_size_dynamic_sections, elf_i386_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf32-metag.c (elf_metag_adjust_dynamic_symbol)
	(elf_metag_size_dynamic_sections, elf_metag_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf32-microblaze.c (microblaze_elf_adjust_dynamic_symbol)
	(microblaze_elf_size_dynamic_sections)
	(microblaze_elf_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf32-nios2.c (nios2_elf32_finish_dynamic_symbol)
	(nios2_elf32_adjust_dynamic_symbol)
	(nios2_elf32_size_dynamic_sections)
	(elf_backend_want_dynrelro): As above.
	* elf32-or1k.c (or1k_elf_finish_dynamic_symbol)
	(or1k_elf_adjust_dynamic_symbol, or1k_elf_size_dynamic_sections)
	(elf_backend_want_dynrelro): As above.
	* elf32-ppc.c (ppc_elf_adjust_dynamic_symbol)
	(ppc_elf_size_dynamic_sections, ppc_elf_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf32-s390.c (elf_s390_adjust_dynamic_symbol)
	(elf_s390_size_dynamic_sections, elf_s390_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf32-tic6x.c (elf32_tic6x_adjust_dynamic_symbol)
	(elf32_tic6x_size_dynamic_sections)
	(elf32_tic6x_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf32-tilepro.c (tilepro_elf_adjust_dynamic_symbol)
	(tilepro_elf_size_dynamic_sections)
	(tilepro_elf_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf64-ppc.c (ppc64_elf_adjust_dynamic_symbol)
	(ppc64_elf_size_dynamic_sections, ppc64_elf_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf64-s390.c (elf_s390_adjust_dynamic_symbol)
	(elf_s390_size_dynamic_sections, elf_s390_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elf64-x86-64.c (elf_x86_64_adjust_dynamic_symbol)
	(elf_x86_64_size_dynamic_sections)
	(elf_x86_64_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elfnn-aarch64.c (elfNN_aarch64_adjust_dynamic_symbol)
	(elfNN_aarch64_size_dynamic_sections)
	(elfNN_aarch64_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elfnn-riscv.c (riscv_elf_adjust_dynamic_symbol)
	(riscv_elf_size_dynamic_sections, riscv_elf_finish_dynamic_symbol)
	(elf_backend_want_dynrelro): As above.
	* elfxx-mips.c (_bfd_mips_elf_adjust_dynamic_symbol)
	(_bfd_mips_elf_size_dynamic_sections)
	(_bfd_mips_vxworks_finish_dynamic_symbol): As above.
	* elfxx-sparc.c (_bfd_sparc_elf_adjust_dynamic_symbol)
	(_bfd_sparc_elf_size_dynamic_sections)
	(_bfd_sparc_elf_finish_dynamic_symbol): As above.
	* elfxx-tilegx.c (tilegx_elf_adjust_dynamic_symbol)
	(tilegx_elf_size_dynamic_sections)
	(tilegx_elf_finish_dynamic_symbol): As above.
	* elf32-mips.c (elf_backend_want_dynrelro): Define.
	* elf64-mips.c (elf_backend_want_dynrelro): Define.
	* elf32-sparc.c (elf_backend_want_dynrelro): Define.
	* elf64-sparc.c (elf_backend_want_dynrelro): Define.
	* elf32-tilegx.c (elf_backend_want_dynrelro): Define.
	* elf64-tilegx.c (elf_backend_want_dynrelro): Define.
	* elf32-microblaze.c (microblaze_elf_adjust_dynamic_symbol): Tidy.
	(microblaze_elf_size_dynamic_sections): Handle sdynbss.
	* elf32-nios2.c (nios2_elf32_size_dynamic_sections): Make use
	of linker shortcuts to dynamic sections rather than comparing
	names.  Correctly set "got" flag.
ld/
	PR ld/20995
	* testsuite/ld-arm/farcall-mixed-app-v5.d: Update to suit changed
	stub hash table traversal caused by section id increment.  Accept
	the previous output too.
	* testsuite/ld-arm/farcall-mixed-app.d: Likewise.
	* testsuite/ld-arm/farcall-mixed-lib-v4t.d: Likewise.
	* testsuite/ld-arm/farcall-mixed-lib.d: Likewise.
	* testsuite/ld-elf/pr20995a.s, * testsuite/ld-elf/pr20995b.s,
	* testsuite/ld-elf/pr20995.r: New test.
	* testsuite/ld-elf/elf.exp: Run it.
2016-12-26 13:47:51 +10:30

136 lines
4.8 KiB
C

/* TILE-Gx-specific support for 32-bit ELF.
Copyright (C) 2011-2016 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elfxx-tilegx.h"
#include "elf32-tilegx.h"
/* Support for core dump NOTE sections. */
static bfd_boolean
tilegx_elf_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
{
int offset;
size_t size;
if (note->descsz != TILEGX_PRSTATUS_SIZEOF)
return FALSE;
/* pr_cursig */
elf_tdata (abfd)->core->signal =
bfd_get_16 (abfd, note->descdata + TILEGX_PRSTATUS_OFFSET_PR_CURSIG);
/* pr_pid */
elf_tdata (abfd)->core->pid =
bfd_get_32 (abfd, note->descdata + TILEGX_PRSTATUS_OFFSET_PR_PID);
/* pr_reg */
offset = TILEGX_PRSTATUS_OFFSET_PR_REG;
size = TILEGX_GREGSET_T_SIZE;
/* Make a ".reg/999" section. */
return _bfd_elfcore_make_pseudosection (abfd, ".reg",
size, note->descpos + offset);
}
static bfd_boolean
tilegx_elf_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
{
if (note->descsz != TILEGX_PRPSINFO_SIZEOF)
return FALSE;
elf_tdata (abfd)->core->program
= _bfd_elfcore_strndup (abfd, note->descdata + TILEGX_PRPSINFO_OFFSET_PR_FNAME, 16);
elf_tdata (abfd)->core->command
= _bfd_elfcore_strndup (abfd, note->descdata + TILEGX_PRPSINFO_OFFSET_PR_PSARGS, ELF_PR_PSARGS_SIZE);
/* Note that for some reason, a spurious space is tacked
onto the end of the args in some (at least one anyway)
implementations, so strip it off if it exists. */
{
char *command = elf_tdata (abfd)->core->command;
int n = strlen (command);
if (0 < n && command[n - 1] == ' ')
command[n - 1] = '\0';
}
return TRUE;
}
#define ELF_ARCH bfd_arch_tilegx
#define ELF_TARGET_ID TILEGX_ELF_DATA
#define ELF_MACHINE_CODE EM_TILEGX
#define ELF_MAXPAGESIZE 0x10000
#define ELF_COMMONPAGESIZE 0x10000
#define TARGET_BIG_SYM tilegx_elf32_be_vec
#define TARGET_BIG_NAME "elf32-tilegx-be"
#define TARGET_LITTLE_SYM tilegx_elf32_le_vec
#define TARGET_LITTLE_NAME "elf32-tilegx-le"
#define elf_backend_reloc_type_class tilegx_reloc_type_class
#define bfd_elf32_bfd_reloc_name_lookup tilegx_reloc_name_lookup
#define bfd_elf32_bfd_link_hash_table_create tilegx_elf_link_hash_table_create
#define bfd_elf32_bfd_reloc_type_lookup tilegx_reloc_type_lookup
#define bfd_elf32_bfd_merge_private_bfd_data \
_bfd_tilegx_elf_merge_private_bfd_data
#define elf_backend_copy_indirect_symbol tilegx_elf_copy_indirect_symbol
#define elf_backend_create_dynamic_sections tilegx_elf_create_dynamic_sections
#define elf_backend_check_relocs tilegx_elf_check_relocs
#define elf_backend_adjust_dynamic_symbol tilegx_elf_adjust_dynamic_symbol
#define elf_backend_omit_section_dynsym tilegx_elf_omit_section_dynsym
#define elf_backend_size_dynamic_sections tilegx_elf_size_dynamic_sections
#define elf_backend_relocate_section tilegx_elf_relocate_section
#define elf_backend_finish_dynamic_symbol tilegx_elf_finish_dynamic_symbol
#define elf_backend_finish_dynamic_sections tilegx_elf_finish_dynamic_sections
#define elf_backend_gc_mark_hook tilegx_elf_gc_mark_hook
#define elf_backend_gc_sweep_hook tilegx_elf_gc_sweep_hook
#define elf_backend_plt_sym_val tilegx_elf_plt_sym_val
#define elf_info_to_howto_rel NULL
#define elf_info_to_howto tilegx_info_to_howto_rela
#define elf_backend_grok_prstatus tilegx_elf_grok_prstatus
#define elf_backend_grok_psinfo tilegx_elf_grok_psinfo
#define elf_backend_additional_program_headers tilegx_additional_program_headers
#define elf_backend_init_index_section _bfd_elf_init_1_index_section
#define elf_backend_can_gc_sections 1
#define elf_backend_can_refcount 1
#define elf_backend_want_got_plt 1
#define elf_backend_plt_readonly 1
/* Align PLT mod 64 byte L2 line size. */
#define elf_backend_plt_alignment 6
#define elf_backend_want_plt_sym 1
#define elf_backend_got_header_size 4
#define elf_backend_want_dynrelro 1
#define elf_backend_rela_normal 1
#define elf_backend_default_execstack 0
#include "elf32-target.h"