* [gold commit] Place copy relocations in .dynbss when target is read-only
@ 2016-12-28 4:45 Cary Coutant
2016-12-28 4:58 ` Cary Coutant
2016-12-28 8:28 ` Andreas Schwab
0 siblings, 2 replies; 6+ messages in thread
From: Cary Coutant @ 2016-12-28 4:45 UTC (permalink / raw)
To: Binutils
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Piggy-backing on PR 20995...
2016-12-27 Cary Coutant <ccoutant@gmail.com>
gold/
PR ld/20995
* copy-relocs.cc (Copy_relocs::make_copy_reloc): Use .dynbss for
read-only data when linking with -z relro.
* copy-relocs.h (Copy_relocs::dynrelro_): New data member.
* testsuite/Makefile.am (copy_test_relro): New test case.
* testsuite/Makefile.in: Regenerate.
* testsuite/copy_test_relro.cc: New source file.
* testsuite/copy_test_relro_1.cc: New source file.
[-- Attachment #2: dynrelro.patch --]
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Place copy relocations in .dynbss when target is read-only.
2016-12-27 Cary Coutant <ccoutant@gmail.com>
gold/
PR ld/20995
* copy-relocs.cc (Copy_relocs::make_copy_reloc): Use .dynbss for
read-only data when linking with -z relro.
* copy-relocs.h (Copy_relocs::dynrelro_): New data member.
* testsuite/Makefile.am (copy_test_relro): New test case.
* testsuite/Makefile.in: Regenerate.
* testsuite/copy_test_relro.cc: New source file.
* testsuite/copy_test_relro_1.cc: New source file.
diff --git a/gold/copy-relocs.cc b/gold/copy-relocs.cc
index ce019c4..4fe17e9 100644
--- a/gold/copy-relocs.cc
+++ b/gold/copy-relocs.cc
@@ -141,6 +141,7 @@ Copy_relocs<sh_type, size, big_endian>::make_copy_reloc(
unsigned int shndx = sym->shndx(&is_ordinary);
gold_assert(is_ordinary);
typename elfcpp::Elf_types<size>::Elf_WXword addralign;
+ bool is_readonly = false;
{
// Lock the object so we can read from it. This is only called
@@ -150,6 +151,17 @@ Copy_relocs<sh_type, size, big_endian>::make_copy_reloc(
Object* obj = sym->object();
Task_lock_obj<Object> tl(dummy_task, obj);
addralign = obj->section_addralign(shndx);
+ if (parameters->options().relro())
+ {
+ if ((obj->section_flags(shndx) & elfcpp::SHF_WRITE) == 0)
+ is_readonly = true;
+ else
+ {
+ // Symbols in .data.rel.ro should also be treated as read-only.
+ if (obj->section_name(shndx) == ".data.rel.ro")
+ is_readonly = true;
+ }
+ }
}
typename Sized_symbol<size>::Value_type value = sym->value();
@@ -159,16 +171,32 @@ Copy_relocs<sh_type, size, big_endian>::make_copy_reloc(
// Mark the dynamic object as needed for the --as-needed option.
sym->object()->set_is_needed();
- if (this->dynbss_ == NULL)
+ Output_data_space* dynbss;
+
+ if (is_readonly)
{
- this->dynbss_ = new Output_data_space(addralign, "** dynbss");
- layout->add_output_section_data(".bss",
- elfcpp::SHT_NOBITS,
- elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
- this->dynbss_, ORDER_BSS, false);
+ if (this->dynrelro_ == NULL)
+ {
+ this->dynrelro_ = new Output_data_space(addralign, "** dynrelro");
+ layout->add_output_section_data(".data.rel.ro",
+ elfcpp::SHT_PROGBITS,
+ elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
+ this->dynrelro_, ORDER_RELRO, false);
+ }
+ dynbss = this->dynrelro_;
+ }
+ else
+ {
+ if (this->dynbss_ == NULL)
+ {
+ this->dynbss_ = new Output_data_space(addralign, "** dynbss");
+ layout->add_output_section_data(".bss",
+ elfcpp::SHT_NOBITS,
+ elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
+ this->dynbss_, ORDER_BSS, false);
+ }
+ dynbss = this->dynbss_;
}
-
- Output_data_space* dynbss = this->dynbss_;
if (addralign > dynbss->addralign())
dynbss->set_space_alignment(addralign);
diff --git a/gold/copy-relocs.h b/gold/copy-relocs.h
index aa42c7c..92b2ceb 100644
--- a/gold/copy-relocs.h
+++ b/gold/copy-relocs.h
@@ -54,7 +54,8 @@ class Copy_relocs
public:
Copy_relocs(unsigned int copy_reloc_type)
- : entries_(), copy_reloc_type_(copy_reloc_type), dynbss_(NULL)
+ : entries_(), copy_reloc_type_(copy_reloc_type), dynbss_(NULL),
+ dynrelro_(NULL)
{ }
// This is called while scanning relocs if we see a relocation
@@ -152,8 +153,11 @@ class Copy_relocs
// The target specific relocation type of the COPY relocation.
const unsigned int copy_reloc_type_;
// The dynamic BSS data which goes into the .bss section. This is
- // where variables which require COPY relocations are placed.
+ // where writable variables which require COPY relocations are placed.
Output_data_space* dynbss_;
+ // The dynamic read-only data, which goes into the .dynbss section. This
+ // is where read-only variables which require COPY relocations are placed.
+ Output_data_space* dynrelro_;
};
} // End namespace gold.
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 6a882ea..d9480ab 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -858,6 +858,16 @@ copy_test_2_pic.o: copy_test_2.cc
copy_test_2.so: gcctestdir/ld copy_test_2_pic.o
$(CXXLINK) -Bgcctestdir/ -shared copy_test_2_pic.o
+check_PROGRAMS += copy_test_relro
+copy_test_relro_SOURCES = copy_test_relro.cc
+copy_test_relro_DEPENDENCIES = gcctestdir/ld copy_test_relro_1.so
+copy_test_relro_LDFLAGS = -Bgcctestdir/ -Wl,-R,. -Wl,-z,relro
+copy_test_relro_LDADD = copy_test_relro_1.so
+copy_test_relro_1_pic.o: copy_test_relro_1.cc
+ $(CXXCOMPILE) -c -fpic -o $@ $<
+copy_test_relro_1.so: gcctestdir/ld copy_test_relro_1_pic.o
+ $(CXXLINK) -Bgcctestdir/ -shared -Wl,-z,relro copy_test_relro_1_pic.o
+
if !DEFAULT_TARGET_POWERPC
check_SCRIPTS += copy_test_protected.sh
check_DATA += copy_test_protected.err
diff --git a/gold/testsuite/copy_test_relro.cc b/gold/testsuite/copy_test_relro.cc
new file mode 100644
index 0000000..297b578
--- /dev/null
+++ b/gold/testsuite/copy_test_relro.cc
@@ -0,0 +1,45 @@
+// copy_test_relro.cc -- test copy relocs against read-only and relro symbols.
+
+// Copyright (C) 2016 Free Software Foundation, Inc.
+// Written by Cary Coutant <ccoutant@gmail.com>.
+
+// This file is part of gold.
+
+// 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 <cassert>
+#include <stdint.h>
+
+extern char* _etext;
+extern char* __data_start;
+extern char* _edata;
+extern char* _end;
+
+extern int* const p;
+extern const int b[];
+int a = 123;
+
+int main()
+{
+ assert(*p == 123);
+ assert(b[0] == 100);
+ assert(b[1] == 200);
+ assert(b[2] == 300);
+ assert(b[3] == 400);
+ assert(reinterpret_cast<const void*>(&p) < reinterpret_cast<void*>(&__data_start));
+ assert(reinterpret_cast<const void*>(b) < reinterpret_cast<void*>(&__data_start));
+ return 0;
+}
diff --git a/gold/testsuite/copy_test_relro_1.cc b/gold/testsuite/copy_test_relro_1.cc
new file mode 100644
index 0000000..d154534
--- /dev/null
+++ b/gold/testsuite/copy_test_relro_1.cc
@@ -0,0 +1,26 @@
+// copy_test_relro_1.cc -- test copy relocs variables for gold
+
+// Copyright (C) 2016 Free Software Foundation, Inc.
+// Written by Cary Coutant <ccoutant@gmail.com>.
+
+// This file is part of gold.
+
+// 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.
+
+extern int a;
+extern int* const p = &a;
+
+extern const int b[] = { 100, 200, 300, 400 };
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [gold commit] Place copy relocations in .dynbss when target is read-only
2016-12-28 4:45 [gold commit] Place copy relocations in .dynbss when target is read-only Cary Coutant
@ 2016-12-28 4:58 ` Cary Coutant
2016-12-28 8:28 ` Andreas Schwab
1 sibling, 0 replies; 6+ messages in thread
From: Cary Coutant @ 2016-12-28 4:58 UTC (permalink / raw)
To: Binutils
> 2016-12-27 Cary Coutant <ccoutant@gmail.com>
>
> gold/
> PR ld/20995
> * copy-relocs.cc (Copy_relocs::make_copy_reloc): Use .dynbss for
> read-only data when linking with -z relro.
> * copy-relocs.h (Copy_relocs::dynrelro_): New data member.
> * testsuite/Makefile.am (copy_test_relro): New test case.
> * testsuite/Makefile.in: Regenerate.
> * testsuite/copy_test_relro.cc: New source file.
> * testsuite/copy_test_relro_1.cc: New source file.
Also backported to binutils-2_28-branch.
-cary
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [gold commit] Place copy relocations in .dynbss when target is read-only
2016-12-28 4:45 [gold commit] Place copy relocations in .dynbss when target is read-only Cary Coutant
2016-12-28 4:58 ` Cary Coutant
@ 2016-12-28 8:28 ` Andreas Schwab
2016-12-28 16:40 ` Cary Coutant
1 sibling, 1 reply; 6+ messages in thread
From: Andreas Schwab @ 2016-12-28 8:28 UTC (permalink / raw)
To: Cary Coutant; +Cc: Binutils
On Dez 27 2016, Cary Coutant <ccoutant@gmail.com> wrote:
> Piggy-backing on PR 20995...
>
> 2016-12-27 Cary Coutant <ccoutant@gmail.com>
>
> gold/
> PR ld/20995
> * copy-relocs.cc (Copy_relocs::make_copy_reloc): Use .dynbss for
s/dynbss/dynrelro/
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [gold commit] Place copy relocations in .dynbss when target is read-only
2016-12-28 8:28 ` Andreas Schwab
@ 2016-12-28 16:40 ` Cary Coutant
2016-12-28 17:35 ` Andreas Schwab
0 siblings, 1 reply; 6+ messages in thread
From: Cary Coutant @ 2016-12-28 16:40 UTC (permalink / raw)
To: Andreas Schwab; +Cc: Binutils
>> 2016-12-27 Cary Coutant <ccoutant@gmail.com>
>>
>> gold/
>> PR ld/20995
>> * copy-relocs.cc (Copy_relocs::make_copy_reloc): Use .dynbss for
>
> s/dynbss/dynrelro/
Fixed, thanks!
-cary
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [gold commit] Place copy relocations in .dynbss when target is read-only
2016-12-28 16:40 ` Cary Coutant
@ 2016-12-28 17:35 ` Andreas Schwab
2016-12-28 19:23 ` Cary Coutant
0 siblings, 1 reply; 6+ messages in thread
From: Andreas Schwab @ 2016-12-28 17:35 UTC (permalink / raw)
To: Cary Coutant; +Cc: Binutils
On Dez 28 2016, Cary Coutant <ccoutant@gmail.com> wrote:
>>> 2016-12-27 Cary Coutant <ccoutant@gmail.com>
>>>
>>> gold/
>>> PR ld/20995
>>> * copy-relocs.cc (Copy_relocs::make_copy_reloc): Use .dynbss for
>>
>> s/dynbss/dynrelro/
>
> Fixed, thanks!
There was a reference in a comment left.
Andreas.
diff --git a/gold/copy-relocs.h b/gold/copy-relocs.h
index 92b2ceb1e8..f5cd0a5529 100644
--- a/gold/copy-relocs.h
+++ b/gold/copy-relocs.h
@@ -155,8 +155,9 @@ class Copy_relocs
// The dynamic BSS data which goes into the .bss section. This is
// where writable variables which require COPY relocations are placed.
Output_data_space* dynbss_;
- // The dynamic read-only data, which goes into the .dynbss section. This
- // is where read-only variables which require COPY relocations are placed.
+ // The dynamic read-only data, which goes into the .data.rel.ro section.
+ // This is where read-only variables which require COPY relocations are
+ // placed.
Output_data_space* dynrelro_;
};
--
2.11.0
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [gold commit] Place copy relocations in .dynbss when target is read-only
2016-12-28 17:35 ` Andreas Schwab
@ 2016-12-28 19:23 ` Cary Coutant
0 siblings, 0 replies; 6+ messages in thread
From: Cary Coutant @ 2016-12-28 19:23 UTC (permalink / raw)
To: Andreas Schwab; +Cc: Binutils
> There was a reference in a comment left.
Oops, thanks!
-cary
^ permalink raw reply [flat|nested] 6+ messages in thread
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2016-12-28 4:45 [gold commit] Place copy relocations in .dynbss when target is read-only Cary Coutant
2016-12-28 4:58 ` Cary Coutant
2016-12-28 8:28 ` Andreas Schwab
2016-12-28 16:40 ` Cary Coutant
2016-12-28 17:35 ` Andreas Schwab
2016-12-28 19:23 ` Cary Coutant
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