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[binutils-gdb] i386: Avoid dynamic symbol with GOT reference in PIE
- From: H.J.Lu <hjl at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 21 Apr 2017 19:03:44 -0000
- Subject: [binutils-gdb] i386: Avoid dynamic symbol with GOT reference in PIE
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e133d00576f3da89e7772149e8d2b6a059d26919
commit e133d00576f3da89e7772149e8d2b6a059d26919
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Fri Apr 21 12:03:14 2017 -0700
i386: Avoid dynamic symbol with GOT reference in PIE
GOT reference to global symbol in PIE will lead to dynamic symbol. It
becomes a problem when "time" or "times" is defined as a variable in
an executable, clashing with functions of the same name in libc. If
a symbol isn't undefined weak symbol, don't make it dynamic in PIE and
generate R_386_RELATIVE relocation.
bfd/
PR ld/21402
* elf32-i386.c (elf_i386_link_hash_entry): Add
no_finish_dynamic_symbol.
(elf_i386_link_hash_newfunc): Set no_finish_dynamic_symbol to 0.
(elf_i386_allocate_dynrelocs): If a symbol isn't undefined weak
symbol, don't make it dynamic in PIE.
(elf_i386_relocate_section): If a symbol isn't dynamic in PIE,
set no_finish_dynamic_symbol and generate R_386_RELATIVE
relocation for R_386_GOT32
(elf_i386_finish_dynamic_symbol): Abort if no_finish_dynamic_symbol
isn't 0.
ld/
PR ld/21402
* testsuite/ld-elf/indirect.exp: Don't skip PIE indirect5 and
indirect6 tests on i386.
Diff:
---
bfd/ChangeLog | 14 +++++++++
bfd/elf32-i386.c | 61 ++++++++++++++++++++++++++++------------
ld/ChangeLog | 6 ++++
ld/testsuite/ld-elf/indirect.exp | 5 ----
4 files changed, 63 insertions(+), 23 deletions(-)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 4576020..ba2d134 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,19 @@
2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
+ PR ld/21402
+ * elf32-i386.c (elf_i386_link_hash_entry): Add
+ no_finish_dynamic_symbol.
+ (elf_i386_link_hash_newfunc): Set no_finish_dynamic_symbol to 0.
+ (elf_i386_allocate_dynrelocs): If a symbol isn't undefined weak
+ symbol, don't make it dynamic in PIE.
+ (elf_i386_relocate_section): If a symbol isn't dynamic in PIE,
+ set no_finish_dynamic_symbol and generate R_386_RELATIVE
+ relocation for R_386_GOT32
+ (elf_i386_finish_dynamic_symbol): Abort if no_finish_dynamic_symbol
+ isn't 0.
+
+2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
+
PR ld/19617
PR ld/21086
* elflink.c (elf_link_add_object_symbols): Require
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 7af6863..9e71974 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -820,6 +820,9 @@ struct elf_i386_link_hash_entry
/* Symbol has non-GOT/non-PLT relocations in text sections. */
unsigned int has_non_got_reloc : 1;
+ /* Don't call finish_dynamic_symbol on this symbol. */
+ unsigned int no_finish_dynamic_symbol : 1;
+
/* 0: symbol isn't ___tls_get_addr.
1: symbol is ___tls_get_addr.
2: symbol is unknown. */
@@ -959,6 +962,7 @@ elf_i386_link_hash_newfunc (struct bfd_hash_entry *entry,
eh->gotoff_ref = 0;
eh->has_got_reloc = 0;
eh->has_non_got_reloc = 0;
+ eh->no_finish_dynamic_symbol = 0;
eh->tls_get_addr = 2;
eh->func_pointer_refcount = 0;
eh->plt_got.offset = (bfd_vma) -1;
@@ -2863,10 +2867,14 @@ elf_i386_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
int tls_type = elf_i386_hash_entry(h)->tls_type;
/* Make sure this symbol is output as a dynamic symbol.
- Undefined weak syms won't yet be marked as dynamic. */
+ Undefined weak syms won't yet be marked as dynamic.
+ PR ld/21402: If this symbol isn't undefined weak symbol,
+ don't make it dynamic in PIE. */
if (h->dynindx == -1
&& !h->forced_local
- && !resolved_to_zero)
+ && !resolved_to_zero
+ && (h->root.type == bfd_link_hash_undefweak
+ || !bfd_link_pie (info)))
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
@@ -3818,6 +3826,7 @@ elf_i386_relocate_section (bfd *output_bfd,
bfd_vma st_size;
asection *resolved_plt;
bfd_boolean resolved_to_zero;
+ bfd_boolean relative_reloc;
r_type = ELF32_R_TYPE (rel->r_info);
if (r_type == R_386_GNU_VTINHERIT
@@ -4268,6 +4277,7 @@ r_386_got32:
if (htab->elf.sgot == NULL)
abort ();
+ relative_reloc = FALSE;
if (h != NULL)
{
bfd_boolean dyn;
@@ -4301,6 +4311,17 @@ r_386_got32:
bfd_put_32 (output_bfd, relocation,
htab->elf.sgot->contents + off);
h->got.offset |= 1;
+
+ if (h->dynindx == -1
+ && !h->forced_local
+ && h->root.type != bfd_link_hash_undefweak
+ && bfd_link_pie (info))
+ {
+ /* PR ld/21402: If this symbol isn't dynamic
+ in PIE, generate R_386_RELATIVE here. */
+ eh->no_finish_dynamic_symbol = 1;
+ relative_reloc = TRUE;
+ }
}
}
else
@@ -4322,27 +4343,29 @@ r_386_got32:
{
bfd_put_32 (output_bfd, relocation,
htab->elf.sgot->contents + off);
+ local_got_offsets[r_symndx] |= 1;
if (bfd_link_pic (info))
- {
- asection *s;
- Elf_Internal_Rela outrel;
-
- s = htab->elf.srelgot;
- if (s == NULL)
- abort ();
-
- outrel.r_offset = (htab->elf.sgot->output_section->vma
- + htab->elf.sgot->output_offset
- + off);
- outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
- elf_append_rel (output_bfd, s, &outrel);
- }
-
- local_got_offsets[r_symndx] |= 1;
+ relative_reloc = TRUE;
}
}
+ if (relative_reloc)
+ {
+ asection *s;
+ Elf_Internal_Rela outrel;
+
+ s = htab->elf.srelgot;
+ if (s == NULL)
+ abort ();
+
+ outrel.r_offset = (htab->elf.sgot->output_section->vma
+ + htab->elf.sgot->output_offset
+ + off);
+ outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
+ elf_append_rel (output_bfd, s, &outrel);
+ }
+
if (off >= (bfd_vma) -2)
abort ();
@@ -5321,6 +5344,8 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
plt_entry_size = GET_PLT_ENTRY_SIZE (output_bfd);
eh = (struct elf_i386_link_hash_entry *) h;
+ if (eh->no_finish_dynamic_symbol)
+ abort ();
/* We keep PLT/GOT entries without dynamic PLT/GOT relocations for
resolved undefined weak symbols in executable so that their
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 86d9e51..c6daa9a 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,5 +1,11 @@
2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
+ PR ld/21402
+ * testsuite/ld-elf/indirect.exp: Don't skip PIE indirect5 and
+ indirect6 tests on i386.
+
+2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
+
PR ld/19617
PR ld/21086
* testsuite/ld-elf/pr19617a.d: Pass --no-dynamic-linker to ld.
diff --git a/ld/testsuite/ld-elf/indirect.exp b/ld/testsuite/ld-elf/indirect.exp
index 2fa374b..fd7d189 100644
--- a/ld/testsuite/ld-elf/indirect.exp
+++ b/ld/testsuite/ld-elf/indirect.exp
@@ -222,11 +222,6 @@ foreach t [list indirect5a indirect5b indirect6a indirect6b] {
}
}
-# PR ld/21402: i386 doesn't support mixing different symbol types in PIE.
-if {[istarget "i?86-*-*"]} {
- return
-}
-
send_log "$CC -fPIE -pie $srcdir/$subdir/main.c -o tmpdir/pie"
catch "exec $CC -fPIE -pie $srcdir/$subdir/main.c -o tmpdir/pie" exec_output
send_log "$exec_output"