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PATCH: PRs binutils/3281/5037: Properly handle PT_GNU_RELRO segment
- From: "H.J. Lu" <hjl at lucon dot org>
- To: binutils at sources dot redhat dot com
- Date: Sun, 16 Sep 2007 12:55:41 -0700
- Subject: PATCH: PRs binutils/3281/5037: Properly handle PT_GNU_RELRO segment
This updated patch fixes PRs binutils/3281/5037.
H.J.
---
bfd/
2007-09-16 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
PR binutils/5037
* 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.
(elf_section_status): New enum.
(rewrite_elf_program_header): Add elf_section_status. Remove
PT_GNU_RELRO segment if a section is modified.
(copy_private_bfd_data): Set p_size and p_size_valid fields for
PT_GNU_RELRO segment. Updated rewrite_elf_program_header call.
include/elf/
2007-09-16 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
PR binutils/5037
* internal.h (elf_segment_map): Add p_size and p_size_valid.
(ELF_IS_SECTION_IN_SEGMENT): Allow SHF_TLS sections in
PT_GNU_RELRO segments.
ld/
2007-09-16 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
PR binutils/5037
* 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.
(find_relro_section_callback): New function.
(lang_find_relro_sections_1): Likewise.
(lang_find_relro_sections): Likewise.
(lang_process): Call lang_find_relro_sections for
non-relocatable link.
ld/testsuite/
2007-09-16 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/3281
PR binutils/5037
* ld-elf/binutils.exp: Update "-z relro" tests to use relro1.s.
Add "-z relro" tests with relro2.s. Add "-z relro" tests with
TLS for objcopy.
* ld-elf/relro1.s: New file.
* ld-elf/relro2.s: Likewise.
--- binutils/bfd/elf-bfd.h.relro 2007-09-16 11:55:37.000000000 -0700
+++ binutils/bfd/elf-bfd.h 2007-09-16 11:55:37.000000000 -0700
@@ -1427,9 +1427,6 @@ 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 2007-09-16 11:55:37.000000000 -0700
+++ binutils/bfd/elf.c 2007-09-16 12:40:37.000000000 -0700
@@ -3361,7 +3361,7 @@ 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. */
@@ -3989,7 +3989,7 @@ _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. */
@@ -4491,12 +4491,10 @@ assign_file_positions_for_load_sections
p->p_memsz += this_hdr->sh_size;
}
- if (p->p_type == PT_GNU_RELRO)
- p->p_align = 1;
- else if (align > p->p_align
- && !m->p_align_valid
- && (p->p_type != PT_LOAD
- || (abfd->flags & D_PAGED) == 0))
+ if (align > p->p_align
+ && !m->p_align_valid
+ && (p->p_type != PT_LOAD
+ || (abfd->flags & D_PAGED) == 0))
p->p_align = align;
}
@@ -4646,18 +4644,58 @@ 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;
+ asection *sect;
+
BFD_ASSERT (!m->includes_filehdr && !m->includes_phdrs);
- hdr = &elf_section_data (m->sections[m->count - 1])->this_hdr;
- p->p_filesz = (m->sections[m->count - 1]->filepos
- - m->sections[0]->filepos);
+ sect = m->sections[m->count - 1];
+ hdr = &elf_section_data (sect)->this_hdr;
+ p->p_filesz = sect->filepos - m->sections[0]->filepos;
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)
+ {
+ /* The end of PT_GNU_RELRO segment is the next
+ SEC_ALLOC section after it if it exists. But
+ we will use p_size if it is valid since it
+ may contain the first few bytes of the next
+ SEC_ALLOC section. */
+ if (m->p_size_valid)
+ p->p_filesz = m->p_size;
+ else if (sect->next != NULL
+ && (sect->next->flags & SEC_ALLOC) != 0)
+ p->p_filesz = sect->next->lma - lp->p_vaddr;
+ else
+ 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
@@ -5092,8 +5130,17 @@ _bfd_elf_symbol_from_bfd_symbol (bfd *ab
/* Rewrite program header information. */
+enum elf_section_status
+{
+ unknown,
+ added,
+ removed,
+ modified
+};
+
static bfd_boolean
-rewrite_elf_program_header (bfd *ibfd, bfd *obfd)
+rewrite_elf_program_header (bfd *ibfd, bfd *obfd,
+ enum elf_section_status status)
{
Elf_Internal_Ehdr *iehdr;
struct elf_segment_map *map;
@@ -5246,7 +5293,14 @@ rewrite_elf_program_header (bfd *ibfd, b
}
if (segment->p_type != PT_LOAD)
- continue;
+ {
+ /* If a section is added or mofied, remove PT_GNU_RELRO
+ segment. */
+ if (status != removed &&
+ segment->p_type == PT_GNU_RELRO)
+ segment->p_type = PT_NULL;
+ continue;
+ }
/* Determine if this segment overlaps any previous segments. */
for (j = 0, segment2 = elf_tdata (ibfd)->phdr; j < i; j++, segment2 ++)
@@ -5770,6 +5824,17 @@ copy_elf_program_header (bfd *ibfd, bfd
map->p_align_valid = 1;
map->p_vaddr_offset = 0;
+ if (map->p_type == PT_GNU_RELRO
+ && segment->p_filesz == segment->p_memsz)
+ {
+ /* The PT_GNU_RELRO segment may contain the first a few
+ bytes in the .got.plt section even if the whole .got.plt
+ section isn't in the PT_GNU_RELRO segment. We won't
+ change the size of the PT_GNU_RELRO segment. */
+ map->p_size = segment->p_filesz;
+ map->p_size_valid = 1;
+ }
+
/* Determine if this segment contains the ELF file header
and if it contains the program headers themselves. */
map->includes_filehdr = (segment->p_offset == 0
@@ -5826,6 +5891,12 @@ copy_elf_program_header (bfd *ibfd, bfd
static bfd_boolean
copy_private_bfd_data (bfd *ibfd, bfd *obfd)
{
+ enum elf_section_status status;
+ Elf_Internal_Phdr *segment;
+ asection *section, *osec;
+ unsigned int i, num_segments;
+ Elf_Internal_Shdr *this_hdr;
+
if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
|| bfd_get_flavour (obfd) != bfd_target_elf_flavour)
return TRUE;
@@ -5833,16 +5904,13 @@ copy_private_bfd_data (bfd *ibfd, bfd *o
if (elf_tdata (ibfd)->phdr == NULL)
return TRUE;
+ status = unknown;
if (ibfd->xvec == obfd->xvec)
{
- /* Check to see if any sections in the input BFD
- covered by ELF program header have changed. */
- Elf_Internal_Phdr *segment;
- asection *section, *osec;
- unsigned int i, num_segments;
- Elf_Internal_Shdr *this_hdr;
+ /* Check to see if any sections in the input BFD covered by ELF
+ program header have changed.
- /* Initialize the segment mark field. */
+ Initialize the segment mark field. */
for (section = obfd->sections; section != NULL;
section = section->next)
section->segment_mark = FALSE;
@@ -5894,7 +5962,10 @@ copy_private_bfd_data (bfd *ibfd, bfd *o
section = section->next)
{
if (section->segment_mark == FALSE)
- goto rewrite;
+ {
+ status = added;
+ goto rewrite;
+ }
else
section->segment_mark = FALSE;
}
@@ -5903,7 +5974,42 @@ copy_private_bfd_data (bfd *ibfd, bfd *o
}
rewrite:
- return rewrite_elf_program_header (ibfd, obfd);
+ if (status == unknown)
+ {
+ /* We need to find out how we are changed. */
+ num_segments = elf_elfheader (ibfd)->e_phnum;
+ for (i = 0, segment = elf_tdata (ibfd)->phdr;
+ i < num_segments;
+ i++, segment++)
+ {
+ for (section = ibfd->sections;
+ section != NULL; section = section->next)
+ {
+ osec = section->output_section;
+
+ /* Check if this section is covered by the segment. */
+ this_hdr = &(elf_section_data(section)->this_hdr);
+ if (ELF_IS_SECTION_IN_SEGMENT_FILE (this_hdr, segment))
+ {
+ if (osec == NULL)
+ status = removed;
+ else if (section->flags != osec->flags
+ || section->lma != osec->lma
+ || section->vma != osec->vma
+ || section->size != osec->size
+ || section->rawsize != osec->rawsize
+ || section->alignment_power != osec->alignment_power)
+ {
+ /* Stop if a section is modified. */
+ status = modified;
+ break;
+ }
+ }
+ }
+ }
+ }
+ BFD_ASSERT (status != unknown);
+ return rewrite_elf_program_header (ibfd, obfd, status);
}
/* Initialize private output section information from input section. */
--- binutils/bfd/elflink.c.relro 2007-09-16 11:55:37.000000000 -0700
+++ binutils/bfd/elflink.c 2007-09-16 11:55:37.000000000 -0700
@@ -5397,7 +5397,6 @@ bfd_elf_size_dynamic_sections (bfd *outp
return TRUE;
bed = get_elf_backend_data (output_bfd);
- 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 2007-05-03 14:07:31.000000000 -0700
+++ binutils/include/elf/internal.h 2007-09-16 12:24:37.000000000 -0700
@@ -239,6 +239,8 @@ struct elf_segment_map
bfd_vma p_vaddr_offset;
/* Program segment alignment. */
bfd_vma p_align;
+ /* Segment size in file and memory */
+ bfd_vma p_size;
/* Whether the p_flags field is valid; if not, the flags are based
on the section flags. */
unsigned int p_flags_valid : 1;
@@ -248,6 +250,9 @@ struct elf_segment_map
/* Whether the p_align field is valid; if not, PT_LOAD segment
alignment is based on the default maximum page size. */
unsigned int p_align_valid : 1;
+ /* Whether the p_size field is valid; if not, the size are based
+ on the section sizes. */
+ unsigned int p_size_valid : 1;
/* Whether this segment includes the file header. */
unsigned int includes_filehdr : 1;
/* Whether this segment includes the program headers. */
@@ -266,11 +271,12 @@ 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
+ 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 2007-08-18 06:22:30.000000000 -0700
+++ binutils/ld/ldexp.c 2007-09-16 11:55:37.000000000 -0700
@@ -390,6 +390,7 @@ 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
@@ -425,6 +426,7 @@ 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 2007-07-09 06:29:44.000000000 -0700
+++ binutils/ld/ldexp.h 2007-09-16 11:55:37.000000000 -0700
@@ -98,6 +98,8 @@ 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;
@@ -125,6 +127,15 @@ 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 2007-08-31 16:00:04.000000000 -0700
+++ binutils/ld/ldlang.c 2007-09-16 11:55:37.000000000 -0700
@@ -4636,10 +4636,32 @@ 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)
@@ -5665,6 +5687,81 @@ lang_gc_sections (void)
bfd_gc_sections (output_bfd, &link_info);
}
+/* Worker for lang_find_relro_sections_1. */
+
+static void
+find_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)
+{
+ /* Discarded, excluded and ignored sections effectively have zero
+ size. */
+ if (section->output_section != NULL
+ && section->output_section->owner == output_bfd
+ && (section->output_section->flags & SEC_EXCLUDE) == 0
+ && !IGNORE_SECTION (section)
+ && section->size != 0)
+ {
+ bfd_boolean *has_relro_section = (bfd_boolean *) data;
+ *has_relro_section = TRUE;
+ }
+}
+
+/* Iterate over sections for relro sections. */
+
+static void
+lang_find_relro_sections_1 (lang_statement_union_type *s,
+ bfd_boolean *has_relro_section)
+{
+ if (*has_relro_section)
+ return;
+
+ 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,
+ find_relro_section_callback,
+ has_relro_section);
+ break;
+ case lang_constructors_statement_enum:
+ lang_find_relro_sections_1 (constructor_list.head,
+ has_relro_section);
+ break;
+ case lang_output_section_statement_enum:
+ lang_find_relro_sections_1 (s->output_section_statement.children.head,
+ has_relro_section);
+ break;
+ case lang_group_statement_enum:
+ lang_find_relro_sections_1 (s->group_statement.children.head,
+ has_relro_section);
+ break;
+ default:
+ break;
+ }
+ }
+}
+
+static void
+lang_find_relro_sections (void)
+{
+ bfd_boolean has_relro_section = FALSE;
+
+ /* Check all sections in the link script. */
+
+ lang_find_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
@@ -5792,6 +5889,10 @@ lang_process (void)
section positions, since they will affect SIZEOF_HEADERS. */
lang_record_phdrs ();
+ /* Check relro sections. */
+ if (link_info.relro && ! link_info.relocatable)
+ lang_find_relro_sections ();
+
/* Size up the sections. */
lang_size_sections (NULL, !command_line.relax);
--- binutils/ld/testsuite/ld-elf/binutils.exp.relro 2007-08-28 06:49:05.000000000 -0700
+++ binutils/ld/testsuite/ld-elf/binutils.exp 2007-09-16 12:42:30.000000000 -0700
@@ -104,24 +104,42 @@ 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" relro1
+binutils_test strip "-z relro -shared" relro1
+binutils_test objcopy "-z relro" relro1
+binutils_test objcopy "-z relro -shared" relro1
+if { ([istarget "i?86-*-elf*"]
+ || ([istarget "i?86-*-linux*"]
+ && ![istarget "*-*-*aout*"]
+ && ![istarget "*-*-*oldld*"])
+ || [istarget "x86_64-*-linux*"]
+ || [istarget "amd64-*-linux*"]) } {
+ binutils_test strip "-z relro -shared" relro2
+ binutils_test objcopy "-z relro -shared" relro2
+}
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/relro1.s.relro 2007-09-16 11:55:37.000000000 -0700
+++ binutils/ld/testsuite/ld-elf/relro1.s 2007-09-16 11:55:37.000000000 -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
--- binutils/ld/testsuite/ld-elf/relro2.s.relro 2007-09-16 12:38:46.000000000 -0700
+++ binutils/ld/testsuite/ld-elf/relro2.s 2007-09-16 12:38:35.000000000 -0700
@@ -0,0 +1,5 @@
+ .text
+ .globl x
+ .type x, @function
+x:
+ jmp foo@PLT