PATCH: PR binutils/3281: objcopy changes PT_GNU_RELRO when there is PT_TLS
H. J. Lu
hjl@lucon.org
Fri Oct 20 12:57:00 GMT 2006
On Thu, Oct 19, 2006 at 08:05:40AM -0700, H. J. Lu wrote:
> On Thu, Sep 28, 2006 at 03:09:16PM -0700, H. J. Lu wrote:
> > When linker creates PT_GNU_RELRO segment, it sets p_vaddr, p_paddr,
> > p_offset, p_filesz from the corresponding PT_LOAD segment and
> > set p_memsz to p_filesz, p_align to 1. My previous fix for PR 3015
> > only handles p_align for objcopy. PT_GNU_RELRO segment will be
> > different after objcopy if there is a PT_TLS segment. This patch
> > puts all PT_GNU_RELRO segment procossing for objcopy into
> > assign_file_positions_for_non_load_sections and uses the same logic
> > as linker.
> >
>
> Could someone please take a look at it:
>
> http://sourceware.org/ml/binutils/2006-09/msg00376.html
>
> Thanks.
>
It turns out that there are other problems with PT_GNU_RELRO. SHF_TLS
sections can be in PT_GNU_RELRO segment. We got it wrong. Also we
may create a PT_NULL segment if there are no relro sections. I noticed
them when I ran "make check" with my patch for Linux/mips64 where
GNU_RELRO segment may only contains .tdata section.
This updated patch addresses those 2 problems.
H.J.
---
bfd/
2006-10-20 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
* elf-bfd.h (elf_obj_tdata): Remove relro.
* elf.c (get_program_header_size): Check info->relro instead
of elf_tdata (abfd)->relro.
(_bfd_elf_map_sections_to_segments): Likewise.
(assign_file_positions_for_load_sections): Don't set
PT_GNU_RELRO segment alignment here.
(assign_file_positions_for_non_load_sections): Properly set up
PT_GNU_RELRO segment for copying executable/shared library.
include/elf/
2006-10-20 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
* internal.h (ELF_IS_SECTION_IN_SEGMENT): Allow SHF_TLS
sections in PT_GNU_RELRO segments.
ld/
2006-10-20 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
* ldexp.h (ldexp_control): Add relro, relro_start_stat and
relro_end_stat.
* ldexp.c (fold_binary): Set expld.dataseg.relro to
exp_dataseg_relro_start or exp_dataseg_relro_end when
seeing DATA_SEGMENT_ALIGN or DATA_SEGMENT_RELRO_END,
respectively.
* ldlang.c (lang_size_sections_1): Properly set
expld.dataseg.relro_start_stat and
expld.dataseg.relro_end_stat.
(size_relro_section_callback): New function.
(lang_size_relro_sections_1): Likewise.
(lang_size_relro_sections): Likewise.
(lang_process): Call lang_size_relro_sections for
non-relocatable link.
ld/testsuite/
2006-10-20 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
* ld-elf/binutils.exp: Update "-z relro" tests to use relro.s.
Add "-z relro" tests with TLS for objcopy.
* ld-elf/relro.s: New file.
--- binutils/bfd/elf-bfd.h.relro 2006-10-19 22:42:57.000000000 -0700
+++ binutils/bfd/elf-bfd.h 2006-10-19 22:42:57.000000000 -0700
@@ -1375,9 +1375,6 @@ struct elf_obj_tdata
/* Segment flags for the PT_GNU_STACK segment. */
unsigned int stack_flags;
- /* Should the PT_GNU_RELRO segment be emitted? */
- bfd_boolean relro;
-
/* Symbol version definitions in external objects. */
Elf_Internal_Verdef *verdef;
--- binutils/bfd/elf.c.relro 2006-10-19 22:42:57.000000000 -0700
+++ binutils/bfd/elf.c 2006-10-19 22:42:57.000000000 -0700
@@ -3633,7 +3633,7 @@ get_program_header_size (bfd *abfd, stru
/* We need a PT_DYNAMIC segment. */
++segs;
- if (elf_tdata (abfd)->relro)
+ if (info->relro)
{
/* We need a PT_GNU_RELRO segment only when there is a
PT_DYNAMIC segment. */
@@ -4121,7 +4121,7 @@ _bfd_elf_map_sections_to_segments (bfd *
pm = &m->next;
}
- if (dynsec != NULL && elf_tdata (abfd)->relro)
+ if (dynsec != NULL && info->relro)
{
/* We make a PT_GNU_RELRO segment only when there is a
PT_DYNAMIC segment. */
@@ -4604,11 +4604,9 @@ assign_file_positions_for_load_sections
p->p_memsz += o->offset + o->size;
}
- if (p->p_type == PT_GNU_RELRO)
- p->p_align = 1;
- else if (align > p->p_align
- && (p->p_type != PT_LOAD
- || (abfd->flags & D_PAGED) == 0))
+ if (align > p->p_align
+ && (p->p_type != PT_LOAD
+ || (abfd->flags & D_PAGED) == 0))
p->p_align = align;
}
@@ -4735,7 +4733,8 @@ assign_file_positions_for_non_load_secti
if (m->count != 0)
{
if (p->p_type != PT_LOAD
- && (p->p_type != PT_NOTE || bfd_get_format (abfd) != bfd_core))
+ && (p->p_type != PT_NOTE
+ || bfd_get_format (abfd) != bfd_core))
{
Elf_Internal_Shdr *hdr;
BFD_ASSERT (!m->includes_filehdr && !m->includes_phdrs);
@@ -4746,7 +4745,33 @@ assign_file_positions_for_non_load_secti
if (hdr->sh_type != SHT_NOBITS)
p->p_filesz += hdr->sh_size;
- p->p_offset = m->sections[0]->filepos;
+ if (p->p_type == PT_GNU_RELRO)
+ {
+ /* When we get here, we are copying executable
+ or shared library. But we need to use the same
+ linker logic. */
+ Elf_Internal_Phdr *lp;
+
+ for (lp = phdrs; lp < phdrs + count; ++lp)
+ {
+ if (lp->p_type == PT_LOAD
+ && lp->p_paddr == p->p_paddr)
+ break;
+ }
+
+ if (lp < phdrs + count)
+ {
+ p->p_filesz += p->p_vaddr - lp->p_vaddr;
+ p->p_vaddr = lp->p_vaddr;
+ p->p_offset = lp->p_offset;
+ p->p_memsz = p->p_filesz;
+ p->p_align = 1;
+ }
+ else
+ abort ();
+ }
+ else
+ p->p_offset = m->sections[0]->filepos;
}
}
else
--- binutils/bfd/elflink.c.relro 2006-10-19 22:42:57.000000000 -0700
+++ binutils/bfd/elflink.c 2006-10-19 22:42:57.000000000 -0700
@@ -5266,7 +5266,6 @@ bfd_elf_size_dynamic_sections (bfd *outp
if (!is_elf_hash_table (info->hash))
return TRUE;
- elf_tdata (output_bfd)->relro = info->relro;
if (info->execstack)
elf_tdata (output_bfd)->stack_flags = PF_R | PF_W | PF_X;
else if (info->noexecstack)
--- binutils/include/elf/internal.h.relro 2006-05-31 22:40:24.000000000 -0700
+++ binutils/include/elf/internal.h 2006-10-19 22:42:57.000000000 -0700
@@ -264,11 +264,12 @@ struct elf_segment_map
|| segment->p_type == PT_TLS) ? sec_hdr->sh_size : 0)
/* Decide if the given sec_hdr is in the given segment. PT_TLS segment
- contains only SHF_TLS sections. Only PT_LOAD and PT_TLS segments
- can contain SHF_TLS sections. */
+ contains only SHF_TLS sections. Only PT_LOAD, PT_GNU_RELRO and
+ PT_TLS segments can contain SHF_TLS sections. */
#define ELF_IS_SECTION_IN_SEGMENT(sec_hdr, segment) \
(((((sec_hdr->sh_flags & SHF_TLS) != 0) \
&& (segment->p_type == PT_TLS \
+ || segment->p_type == PT_GNU_RELRO \
|| segment->p_type == PT_LOAD)) \
|| ((sec_hdr->sh_flags & SHF_TLS) == 0 \
&& segment->p_type != PT_TLS)) \
--- binutils/ld/ldexp.c.relro 2006-08-22 18:35:31.000000000 -0700
+++ binutils/ld/ldexp.c 2006-10-19 22:42:57.000000000 -0700
@@ -384,6 +384,7 @@ fold_binary (etree_type *tree)
break;
case DATA_SEGMENT_ALIGN:
+ expld.dataseg.relro = exp_dataseg_relro_start;
if (expld.phase != lang_first_phase_enum
&& expld.section == bfd_abs_section_ptr
&& (expld.dataseg.phase == exp_dataseg_none
@@ -419,6 +420,7 @@ fold_binary (etree_type *tree)
break;
case DATA_SEGMENT_RELRO_END:
+ expld.dataseg.relro = exp_dataseg_relro_end;
if (expld.phase != lang_first_phase_enum
&& (expld.dataseg.phase == exp_dataseg_align_seen
|| expld.dataseg.phase == exp_dataseg_adjust
--- binutils/ld/ldexp.h.relro 2005-08-05 06:52:13.000000000 -0700
+++ binutils/ld/ldexp.h 2006-10-19 22:42:57.000000000 -0700
@@ -97,6 +97,8 @@ typedef enum {
lang_final_phase_enum
} lang_phase_type;
+union lang_statement_union;
+
struct ldexp_control {
/* Modify expression evaluation depending on this. */
lang_phase_type phase;
@@ -124,6 +126,15 @@ struct ldexp_control {
} phase;
bfd_vma base, min_base, relro_end, end, pagesize, maxpagesize;
+
+ enum {
+ exp_dataseg_relro_none,
+ exp_dataseg_relro_start,
+ exp_dataseg_relro_end,
+ } relro;
+
+ union lang_statement_union *relro_start_stat;
+ union lang_statement_union *relro_end_stat;
} dataseg;
};
--- binutils/ld/ldlang.c.relro 2006-10-19 22:42:57.000000000 -0700
+++ binutils/ld/ldlang.c 2006-10-19 23:03:21.000000000 -0700
@@ -4627,10 +4627,32 @@ lang_size_sections_1
bfd_vma newdot = dot;
etree_type *tree = s->assignment_statement.exp;
+ expld.dataseg.relro = exp_dataseg_relro_none;
+
exp_fold_tree (tree,
output_section_statement->bfd_section,
&newdot);
+ if (expld.dataseg.relro == exp_dataseg_relro_start)
+ {
+ if (!expld.dataseg.relro_start_stat)
+ expld.dataseg.relro_start_stat = s;
+ else
+ {
+ ASSERT (expld.dataseg.relro_start_stat == s);
+ }
+ }
+ else if (expld.dataseg.relro == exp_dataseg_relro_end)
+ {
+ if (!expld.dataseg.relro_end_stat)
+ expld.dataseg.relro_end_stat = s;
+ else
+ {
+ ASSERT (expld.dataseg.relro_end_stat == s);
+ }
+ }
+ expld.dataseg.relro = exp_dataseg_relro_none;
+
/* This symbol is relative to this section. */
if ((tree->type.node_class == etree_provided
|| tree->type.node_class == etree_assign)
@@ -5607,6 +5629,74 @@ lang_gc_sections (void)
bfd_gc_sections (output_bfd, &link_info);
}
+/* Worker for lang_size_relro_sections_1. */
+
+static void
+size_relro_section_callback (lang_wild_statement_type *ptr ATTRIBUTE_UNUSED,
+ struct wildcard_list *sec ATTRIBUTE_UNUSED,
+ asection *section,
+ lang_input_statement_type *file ATTRIBUTE_UNUSED,
+ void *data)
+{
+ /* .tbss sections effectively have zero size. */
+ if ((section->flags & SEC_HAS_CONTENTS) != 0
+ || (section->flags & SEC_THREAD_LOCAL) == 0)
+ {
+ bfd_boolean *has_relro_section = (bfd_boolean *) data;
+ *has_relro_section |= section->size != 0;
+ }
+}
+
+/* Iterate over sections for relro sections. */
+
+static void
+lang_size_relro_sections_1 (lang_statement_union_type *s,
+ bfd_boolean *has_relro_section)
+{
+ for (; s != NULL; s = s->header.next)
+ {
+ if (s == expld.dataseg.relro_end_stat)
+ break;
+
+ switch (s->header.type)
+ {
+ case lang_wild_statement_enum:
+ walk_wild (&s->wild_statement,
+ size_relro_section_callback,
+ has_relro_section);
+ break;
+ case lang_constructors_statement_enum:
+ lang_size_relro_sections_1 (constructor_list.head,
+ has_relro_section);
+ break;
+ case lang_output_section_statement_enum:
+ lang_size_relro_sections_1 (s->output_section_statement.children.head,
+ has_relro_section);
+ break;
+ case lang_group_statement_enum:
+ lang_size_relro_sections_1 (s->group_statement.children.head,
+ has_relro_section);
+ break;
+ default:
+ break;
+ }
+ }
+}
+
+static void
+lang_size_relro_sections (void)
+{
+ bfd_boolean has_relro_section = FALSE;
+
+ /* Check all sections in the link script. */
+
+ lang_size_relro_sections_1 (expld.dataseg.relro_start_stat,
+ &has_relro_section);
+
+ if (!has_relro_section)
+ link_info.relro = FALSE;
+}
+
/* Relax all sections until bfd_relax_section gives up. */
static void
@@ -5732,6 +5822,10 @@ lang_process (void)
section positions, since they will affect SIZEOF_HEADERS. */
lang_record_phdrs ();
+ /* Check relro sections. */
+ if (! link_info.relocatable)
+ lang_size_relro_sections ();
+
/* Size up the sections. */
lang_size_sections (NULL, !command_line.relax);
--- binutils/ld/testsuite/ld-elf/binutils.exp.relro 2006-08-16 19:04:53.000000000 -0700
+++ binutils/ld/testsuite/ld-elf/binutils.exp 2006-10-19 22:42:57.000000000 -0700
@@ -101,24 +101,33 @@ binutils_test strip "-shared" maxpage1
binutils_test objcopy "" maxpage1
binutils_test objcopy "-shared" maxpage1
-binutils_test strip "-z relro" maxpage1
-binutils_test strip "-z relro -shared" maxpage1
-binutils_test objcopy "-z relro" maxpage1
-binutils_test objcopy "-z relro -shared" maxpage1
+binutils_test strip "-z relro" relro
+binutils_test strip "-z relro -shared" relro
+binutils_test objcopy "-z relro" relro
+binutils_test objcopy "-z relro -shared" relro
binutils_test objcopy "" tbss1
+binutils_test objcopy "-z relro" tbss1
binutils_test objcopy "-shared" tbss1
+binutils_test objcopy "-shared -z relro" tbss1
binutils_test objcopy "-z max-page-size=0x100000" tbss1
binutils_test objcopy "-z max-page-size=0x100000 -z common-page-size=0x1000" tbss1
binutils_test objcopy "" tdata1
+binutils_test objcopy "-z relro" tdata1
binutils_test objcopy "-shared" tdata1
+binutils_test objcopy "-shared -z relro" tdata1
binutils_test objcopy "-z max-page-size=0x100000" tdata1
binutils_test objcopy "-z max-page-size=0x100000 -z common-page-size=0x1000" tdata1
binutils_test objcopy "" tbss2
+binutils_test objcopy "-z relro" tbss2
binutils_test objcopy "-shared" tbss2
+binutils_test objcopy "-shared -z relro" tbss2
binutils_test objcopy "-z max-page-size=0x100000" tbss2
binutils_test objcopy "-z max-page-size=0x100000 -z common-page-size=0x1000" tbss2
-binutils_test objcopy "-z max-page-size=0x100000" tdata2
+
binutils_test objcopy "" tdata2
+binutils_test objcopy "-z relro" tdata2
binutils_test objcopy "-shared" tdata2
+binutils_test objcopy "-shared -z relro" tdata2
+binutils_test objcopy "-z max-page-size=0x100000" tdata2
binutils_test objcopy "-z max-page-size=0x100000 -z common-page-size=0x1000" tdata2
--- binutils/ld/testsuite/ld-elf/relro.s.relro 2006-10-19 22:42:57.000000000 -0700
+++ binutils/ld/testsuite/ld-elf/relro.s 2006-10-19 22:42:57.000000000 -0700
@@ -0,0 +1,14 @@
+ .globl main
+ .globl start
+ .globl _start
+ .globl __start
+ .text
+main:
+start:
+_start:
+__start:
+ .long 0
+ .data
+ .long 0
+ .section .data.rel.ro,"aw",%progbits
+ .long 0
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