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Adjust LOAD segment to generate GNU_RELRO segment 

This patch fixes 2 GNU_RELRO segment bugs:

1. lang_size_sections didn't properly align base to the maximum
alignment power of sections between DATA_SEGMENT_ALIGN and
DATA_SEGMENT_RELRO_END.
2. ld failed to adjust LOAD segment to generate GNU_RELRO segment
when LOAD segment doesn't fit GNU_RELRO segment.  This is

https://sourceware.org/bugzilla/show_bug.cgi?id=14207

We "fixed" ld by not generating GNU_RELRO segment.  This patch
adjusts LOAD segment to generate GNU_RELRO segment.  It fixes
PR ld/16322 and at the same time it also fixes PR binutils/16323
since now we can adjust LOAD segment if it is too small.

bfd/

	PR ld/14207
	PR ld/16322
	PR binutils/16323
	* elf.c (_bfd_elf_map_sections_to_segments): Don't check section
	size for PT_GNU_RELRO segment.
	(assign_file_positions_for_load_sections): If PT_LOAD segment
	doesn't fit PT_GNU_RELRO segment, adjust its p_filesz and p_memsz.

ld/

	PR ld/14207
	PR ld/16322
	PR binutils/16323
	* ldlang.c (lang_size_sections): Properly align RELRO base.

ld/testsuite/

	PR ld/14207
	PR ld/16322
	PR binutils/16323
	* ld-elf/pr16322.d: New file.
	* ld-elf/pr16322.s: Likewise.

	* ld-x86-64/pr14207.d: Expect PT_GNU_RELRO segment.
This commit is contained in:
H.J. Lu 2013-12-12 10:35:47 -08:00
parent 221fd5d598
commit 43a8475ca0
8 changed files with 97 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
bfd/ChangeLog
View File

@ -1,3 +1,13 @@
2014-01-08 H.J. Lu <hongjiu.lu@intel.com>
PR ld/14207
PR ld/16322
PR binutils/16323
* elf.c (_bfd_elf_map_sections_to_segments): Don't check section
size for PT_GNU_RELRO segment.
(assign_file_positions_for_load_sections): If PT_LOAD segment
doesn't fit PT_GNU_RELRO segment, adjust its p_filesz and p_memsz.
2014-01-07 Tom Tromey <tromey@redhat.com>
* elf32-xtensa.c (vsprint_msg): Don't use old VA_* compatibility

41
bfd/elf.c
View File

@ -4184,11 +4184,7 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info)
== (SEC_LOAD | SEC_HAS_CONTENTS))
break;
if (i == (unsigned) -1)
continue;
if (m->sections[i]->vma + m->sections[i]->size
>= info->relro_end)
if (i != (unsigned) -1)
break;
}
}
@ -4380,6 +4376,7 @@ assign_file_positions_for_load_sections (bfd *abfd,
unsigned int alloc;
unsigned int i, j;
bfd_vma header_pad = 0;
bfd_vma relro_start = 0, relro_end = 0;
if (link_info == NULL
&& !_bfd_elf_map_sections_to_segments (abfd, link_info))
@ -4450,6 +4447,23 @@ assign_file_positions_for_load_sections (bfd *abfd,
header_pad -= off;
off += header_pad;
/* Get start and end of PT_GNU_RELRO segment. */
if (link_info != NULL)
{
relro_start = link_info->relro_start;
relro_end = link_info->relro_end;
}
else
{
for (m = elf_seg_map (abfd); m != NULL; m = m->next)
if (m->p_type == PT_GNU_RELRO)
{
relro_start = m->p_paddr;
relro_end = relro_start + m->p_size;
break;
}
}
for (m = elf_seg_map (abfd), p = phdrs, j = 0;
m != NULL;
m = m->next, p++, j++)
@ -4792,6 +4806,23 @@ assign_file_positions_for_load_sections (bfd *abfd,
p->p_flags |= PF_W;
}
}
if (relro_start != 0
&& p->p_type == PT_LOAD
&& p->p_vaddr >= relro_start)
{
/* If PT_LOAD segment doesn't fit PT_GNU_RELRO segment,
adjust its p_filesz and p_memsz. */
if (p->p_vaddr + p->p_filesz < relro_end)
{
bfd_vma adjust = relro_end - (p->p_vaddr + p->p_filesz);
p->p_filesz += adjust;
off += adjust;
}
if (p->p_vaddr + p->p_memsz < relro_end)
p->p_memsz += relro_end - (p->p_vaddr + p->p_memsz);
}
off -= off_adjust;
/* Check that all sections are in a PT_LOAD segment.

7
ld/ChangeLog
View File

@ -1,3 +1,10 @@
2014-01-08 H.J. Lu <hongjiu.lu@intel.com>
PR ld/14207
PR ld/16322
PR binutils/16323
* ldlang.c (lang_size_sections): Properly align RELRO base.
2014-01-08 H.J. Lu <hongjiu.lu@intel.com>
* ldver.c (ldversion): Update copyright year to 2014.

3
ld/ldlang.c
View File

@ -5407,7 +5407,8 @@ lang_size_sections (bfd_boolean *relax, bfd_boolean check_regions)
{
if (expld.dataseg.base - (1 << max_alignment_power) < old_base)
expld.dataseg.base += expld.dataseg.pagesize;
expld.dataseg.base -= (1 << max_alignment_power);
/* Properly align base to max_alignment_power. */
expld.dataseg.base &= ~((1 << max_alignment_power) - 1);
lang_reset_memory_regions ();
one_lang_size_sections_pass (relax, check_regions);
}

10
ld/testsuite/ChangeLog
View File

@ -1,3 +1,13 @@
2014-01-08 H.J. Lu <hongjiu.lu@intel.com>
PR ld/14207
PR ld/16322
PR binutils/16323
* ld-elf/pr16322.d: New file.
* ld-elf/pr16322.s: Likewise.
* ld-x86-64/pr14207.d: Expect PT_GNU_RELRO segment.
For older changes see ChangeLog-2013
Copyright (C) 2014 Free Software Foundation, Inc.

7
ld/testsuite/ld-elf/pr16322.d Normal file
View File

@ -0,0 +1,7 @@
#ld: -shared -z relro
#readelf: -l --wide
#target: *-*-linux-gnu *-*-gnu* *-*-nacl*
#...
GNU_RELRO .*
#pass

6
ld/testsuite/ld-elf/pr16322.s Normal file
View File

@ -0,0 +1,6 @@
.globl p1
.section .data.rel.ro,"aw",%progbits
.p2align 5
.type p1, %object
p1:
.dc.a f1

23
ld/testsuite/ld-x86-64/pr14207.d
View File

@ -2,8 +2,23 @@
#as: --64
#ld: -melf_x86_64 -shared -z relro -z now
#readelf: -l --wide
#target: x86_64-*-linux*
#failif
#...
NULL +.*
#...
Elf file type is DYN \(Shared object file\)
Entry point 0x1d9
There are 4 program headers, starting at offset 64
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x0001e0 0x0001e0 R 0x200000
LOAD 0x000b48 0x0000000000200b48 0x0000000000200b48 0x0004b8 0x000cf8 RW 0x200000
DYNAMIC 0x000b90 0x0000000000200b90 0x0000000000200b90 0x0001c0 0x0001c0 RW 0x8
GNU_RELRO 0x000b48 0x0000000000200b48 0x0000000000200b48 0x0004b8 0x0004b8 R 0x1
Section to Segment mapping:
Segment Sections...
00 .hash .dynsym .dynstr
01 .init_array .fini_array .jcr .data.rel.ro .dynamic .got .bss
02 .dynamic
03 .init_array .fini_array .jcr .data.rel.ro .dynamic .got
#pass