darling-gdb/bfd/elf32-sparc.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

358 lines
11 KiB
C

/* SPARC-specific support for 32-bit ELF
Copyright (C) 1993-2016 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 "bfdlink.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf/sparc.h"
#include "opcode/sparc.h"
#include "elfxx-sparc.h"
#include "elf-vxworks.h"
/* Support for core dump NOTE sections. */
static bfd_boolean
elf32_sparc_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
{
switch (note->descsz)
{
default:
return FALSE;
case 260: /* Solaris prpsinfo_t. */
elf_tdata (abfd)->core->program
= _bfd_elfcore_strndup (abfd, note->descdata + 84, 16);
elf_tdata (abfd)->core->command
= _bfd_elfcore_strndup (abfd, note->descdata + 100, 80);
break;
case 336: /* Solaris psinfo_t. */
elf_tdata (abfd)->core->program
= _bfd_elfcore_strndup (abfd, note->descdata + 88, 16);
elf_tdata (abfd)->core->command
= _bfd_elfcore_strndup (abfd, note->descdata + 104, 80);
break;
}
return TRUE;
}
/* Functions for dealing with the e_flags field.
We don't define set_private_flags or copy_private_bfd_data because
the only currently defined values are based on the bfd mach number,
so we use the latter instead and defer setting e_flags until the
file is written out. */
/* Merge backend specific data from an object file to the output
object file when linking. */
static bfd_boolean
elf32_sparc_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
{
bfd *obfd = info->output_bfd;
bfd_boolean error;
unsigned long ibfd_mach;
/* FIXME: This should not be static. */
static unsigned long previous_ibfd_e_flags = (unsigned long) -1;
if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
|| bfd_get_flavour (obfd) != bfd_target_elf_flavour)
return TRUE;
error = FALSE;
ibfd_mach = bfd_get_mach (ibfd);
if (bfd_mach_sparc_64bit_p (ibfd_mach))
{
error = TRUE;
_bfd_error_handler
(_("%B: compiled for a 64 bit system and target is 32 bit"), ibfd);
}
else if ((ibfd->flags & DYNAMIC) == 0)
{
if (bfd_get_mach (obfd) < ibfd_mach)
bfd_set_arch_mach (obfd, bfd_arch_sparc, ibfd_mach);
}
if (((elf_elfheader (ibfd)->e_flags & EF_SPARC_LEDATA)
!= previous_ibfd_e_flags)
&& previous_ibfd_e_flags != (unsigned long) -1)
{
_bfd_error_handler
(_("%B: linking little endian files with big endian files"), ibfd);
error = TRUE;
}
previous_ibfd_e_flags = elf_elfheader (ibfd)->e_flags & EF_SPARC_LEDATA;
if (error)
{
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
return _bfd_sparc_elf_merge_private_bfd_data (ibfd, info);
}
/* The final processing done just before writing out the object file.
We need to set the e_machine field appropriately. */
static void
elf32_sparc_final_write_processing (bfd *abfd,
bfd_boolean linker ATTRIBUTE_UNUSED)
{
switch (bfd_get_mach (abfd))
{
case bfd_mach_sparc :
case bfd_mach_sparc_sparclet :
case bfd_mach_sparc_sparclite :
break; /* nothing to do */
case bfd_mach_sparc_v8plus :
elf_elfheader (abfd)->e_machine = EM_SPARC32PLUS;
elf_elfheader (abfd)->e_flags &=~ EF_SPARC_32PLUS_MASK;
elf_elfheader (abfd)->e_flags |= EF_SPARC_32PLUS;
break;
case bfd_mach_sparc_v8plusa :
elf_elfheader (abfd)->e_machine = EM_SPARC32PLUS;
elf_elfheader (abfd)->e_flags &=~ EF_SPARC_32PLUS_MASK;
elf_elfheader (abfd)->e_flags |= EF_SPARC_32PLUS | EF_SPARC_SUN_US1;
break;
case bfd_mach_sparc_v8plusb :
case bfd_mach_sparc_v8plusc :
case bfd_mach_sparc_v8plusd :
case bfd_mach_sparc_v8pluse :
case bfd_mach_sparc_v8plusv :
case bfd_mach_sparc_v8plusm :
elf_elfheader (abfd)->e_machine = EM_SPARC32PLUS;
elf_elfheader (abfd)->e_flags &=~ EF_SPARC_32PLUS_MASK;
elf_elfheader (abfd)->e_flags |= EF_SPARC_32PLUS | EF_SPARC_SUN_US1
| EF_SPARC_SUN_US3;
break;
case bfd_mach_sparc_sparclite_le :
elf_elfheader (abfd)->e_flags |= EF_SPARC_LEDATA;
break;
default :
abort ();
break;
}
}
static enum elf_reloc_type_class
elf32_sparc_reloc_type_class (const struct bfd_link_info *info ATTRIBUTE_UNUSED,
const asection *rel_sec ATTRIBUTE_UNUSED,
const Elf_Internal_Rela *rela)
{
switch ((int) ELF32_R_TYPE (rela->r_info))
{
case R_SPARC_RELATIVE:
return reloc_class_relative;
case R_SPARC_JMP_SLOT:
return reloc_class_plt;
case R_SPARC_COPY:
return reloc_class_copy;
default:
return reloc_class_normal;
}
}
/* Hook called by the linker routine which adds symbols from an object
file. */
static bfd_boolean
elf32_sparc_add_symbol_hook (bfd * abfd,
struct bfd_link_info * info,
Elf_Internal_Sym * sym,
const char ** namep ATTRIBUTE_UNUSED,
flagword * flagsp ATTRIBUTE_UNUSED,
asection ** secp ATTRIBUTE_UNUSED,
bfd_vma * valp ATTRIBUTE_UNUSED)
{
if (ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
&& (abfd->flags & DYNAMIC) == 0
&& bfd_get_flavour (info->output_bfd) == bfd_target_elf_flavour)
elf_tdata (info->output_bfd)->has_gnu_symbols |= elf_gnu_symbol_ifunc;
return TRUE;
}
#define TARGET_BIG_SYM sparc_elf32_vec
#define TARGET_BIG_NAME "elf32-sparc"
#define ELF_ARCH bfd_arch_sparc
#define ELF_TARGET_ID SPARC_ELF_DATA
#define ELF_MACHINE_CODE EM_SPARC
#define ELF_MACHINE_ALT1 EM_SPARC32PLUS
#define ELF_MAXPAGESIZE 0x10000
#define ELF_COMMONPAGESIZE 0x2000
#define bfd_elf32_bfd_merge_private_bfd_data \
elf32_sparc_merge_private_bfd_data
#define elf_backend_final_write_processing \
elf32_sparc_final_write_processing
#define elf_backend_grok_psinfo elf32_sparc_grok_psinfo
#define elf_backend_reloc_type_class elf32_sparc_reloc_type_class
#define elf_info_to_howto _bfd_sparc_elf_info_to_howto
#define bfd_elf32_bfd_reloc_type_lookup _bfd_sparc_elf_reloc_type_lookup
#define bfd_elf32_bfd_reloc_name_lookup \
_bfd_sparc_elf_reloc_name_lookup
#define bfd_elf32_bfd_link_hash_table_create \
_bfd_sparc_elf_link_hash_table_create
#define bfd_elf32_bfd_relax_section _bfd_sparc_elf_relax_section
#define bfd_elf32_new_section_hook _bfd_sparc_elf_new_section_hook
#define elf_backend_copy_indirect_symbol \
_bfd_sparc_elf_copy_indirect_symbol
#define elf_backend_create_dynamic_sections \
_bfd_sparc_elf_create_dynamic_sections
#define elf_backend_check_relocs _bfd_sparc_elf_check_relocs
#define elf_backend_adjust_dynamic_symbol \
_bfd_sparc_elf_adjust_dynamic_symbol
#define elf_backend_omit_section_dynsym _bfd_sparc_elf_omit_section_dynsym
#define elf_backend_size_dynamic_sections \
_bfd_sparc_elf_size_dynamic_sections
#define elf_backend_relocate_section _bfd_sparc_elf_relocate_section
#define elf_backend_finish_dynamic_symbol \
_bfd_sparc_elf_finish_dynamic_symbol
#define elf_backend_finish_dynamic_sections \
_bfd_sparc_elf_finish_dynamic_sections
#define bfd_elf32_mkobject _bfd_sparc_elf_mkobject
#define elf_backend_object_p _bfd_sparc_elf_object_p
#define elf_backend_gc_mark_hook _bfd_sparc_elf_gc_mark_hook
#define elf_backend_gc_sweep_hook _bfd_sparc_elf_gc_sweep_hook
#define elf_backend_plt_sym_val _bfd_sparc_elf_plt_sym_val
#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 0
#define elf_backend_plt_readonly 0
#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_add_symbol_hook elf32_sparc_add_symbol_hook
#include "elf32-target.h"
/* Solaris 2. */
#undef TARGET_BIG_SYM
#define TARGET_BIG_SYM sparc_elf32_sol2_vec
#undef TARGET_BIG_NAME
#define TARGET_BIG_NAME "elf32-sparc-sol2"
#undef elf32_bed
#define elf32_bed elf32_sparc_sol2_bed
/* The 32-bit static TLS arena size is rounded to the nearest 8-byte
boundary. */
#undef elf_backend_static_tls_alignment
#define elf_backend_static_tls_alignment 8
#undef elf_backend_strtab_flags
#define elf_backend_strtab_flags SHF_STRINGS
static bfd_boolean
elf32_sparc_copy_solaris_special_section_fields (const bfd *ibfd ATTRIBUTE_UNUSED,
bfd *obfd ATTRIBUTE_UNUSED,
const Elf_Internal_Shdr *isection ATTRIBUTE_UNUSED,
Elf_Internal_Shdr *osection ATTRIBUTE_UNUSED)
{
/* PR 19938: FIXME: Need to add code for setting the sh_info
and sh_link fields of Solaris specific section types. */
return FALSE;
}
#undef elf_backend_copy_special_section_fields
#define elf_backend_copy_special_section_fields elf32_sparc_copy_solaris_special_section_fields
#include "elf32-target.h"
/* A wrapper around _bfd_sparc_elf_link_hash_table_create that identifies
the target system as VxWorks. */
static struct bfd_link_hash_table *
elf32_sparc_vxworks_link_hash_table_create (bfd *abfd)
{
struct bfd_link_hash_table *ret;
ret = _bfd_sparc_elf_link_hash_table_create (abfd);
if (ret)
{
struct _bfd_sparc_elf_link_hash_table *htab;
htab = (struct _bfd_sparc_elf_link_hash_table *) ret;
htab->is_vxworks = 1;
}
return ret;
}
/* A final_write_processing hook that does both the SPARC- and VxWorks-
specific handling. */
static void
elf32_sparc_vxworks_final_write_processing (bfd *abfd, bfd_boolean linker)
{
elf32_sparc_final_write_processing (abfd, linker);
elf_vxworks_final_write_processing (abfd, linker);
}
#undef TARGET_BIG_SYM
#define TARGET_BIG_SYM sparc_elf32_vxworks_vec
#undef TARGET_BIG_NAME
#define TARGET_BIG_NAME "elf32-sparc-vxworks"
#undef ELF_MINPAGESIZE
#define ELF_MINPAGESIZE 0x1000
#undef bfd_elf32_bfd_link_hash_table_create
#define bfd_elf32_bfd_link_hash_table_create \
elf32_sparc_vxworks_link_hash_table_create
#undef elf_backend_want_got_plt
#define elf_backend_want_got_plt 1
#undef elf_backend_plt_readonly
#define elf_backend_plt_readonly 1
#undef elf_backend_got_header_size
#define elf_backend_got_header_size 12
#undef elf_backend_dtrel_excludes_plt
#define elf_backend_dtrel_excludes_plt 1
#undef elf_backend_add_symbol_hook
#define elf_backend_add_symbol_hook \
elf_vxworks_add_symbol_hook
#undef elf_backend_link_output_symbol_hook
#define elf_backend_link_output_symbol_hook \
elf_vxworks_link_output_symbol_hook
#undef elf_backend_emit_relocs
#define elf_backend_emit_relocs \
elf_vxworks_emit_relocs
#undef elf_backend_final_write_processing
#define elf_backend_final_write_processing \
elf32_sparc_vxworks_final_write_processing
#undef elf_backend_static_tls_alignment
#undef elf_backend_strtab_flags
#undef elf_backend_copy_special_section_fields
#undef elf32_bed
#define elf32_bed sparc_elf_vxworks_bed
#include "elf32-target.h"