PING^N: [PATCH] Add --enable-static-pie to build static PIE [BZ #19574]
Commit Message
On Fri, Nov 24, 2017 at 7:03 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Nov 24, 2017 at 5:06 AM, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>> On 23/11/17 13:59, H.J. Lu wrote:
>>> On Mon, Nov 20, 2017 at 4:16 AM, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>>>> On 19/11/17 02:40, H.J. Lu wrote:
>>>>> 3. Linker should resolve undefined weak symbols to 0 in static PIE:
>>>>>
>>>>> https://sourceware.org/bugzilla/show_bug.cgi?id=22269
>>>>>
>>>>> 4. Many ELF backend linkers incorrectly check bfd_link_pic for TLS
>>>>> relocations, which should check bfd_link_executable instead:
>>>>>
>>>>> https://sourceware.org/bugzilla/show_bug.cgi?id=22263
>>>>>
>>>>> Tested on i686 and x86-64.
>>>>>
>>>>> Build results of build-many-glibcs.py with --enable-static-pie with all
>>>>> patches for static PIE applied are
>>>>>
>>>>> PASS: glibcs-aarch64_be-linux-gnu build
>>>>> PASS: glibcs-aarch64-linux-gnu build
>>>>
>>>> i'd expect these to fail on current binutils master
>>>>
>>>> (linking with undefweak symbol fails now because of the issues
>>>> listed above, i'll try to prepare a binutils patch)
>>>>
>>>
>>> Do you think you can fix arm64 for glibc 2.27?
>>>
>>
>> the aarch64 glibc tests pass with the pie patches and
>> the start code fix i posted (and with a fixed bfd linker).
>
> Great. Linker changes look quite straight forward. I will
> update my commit message.
Here is the patch with the updated commit message.
Thanks.
Comments
On Fri, Nov 24, 2017 at 2:24 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Nov 24, 2017 at 7:03 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Nov 24, 2017 at 5:06 AM, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>>> On 23/11/17 13:59, H.J. Lu wrote:
>>>> On Mon, Nov 20, 2017 at 4:16 AM, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>>>>> On 19/11/17 02:40, H.J. Lu wrote:
>>>>>> 3. Linker should resolve undefined weak symbols to 0 in static PIE:
>>>>>>
>>>>>> https://sourceware.org/bugzilla/show_bug.cgi?id=22269
>>>>>>
>>>>>> 4. Many ELF backend linkers incorrectly check bfd_link_pic for TLS
>>>>>> relocations, which should check bfd_link_executable instead:
>>>>>>
>>>>>> https://sourceware.org/bugzilla/show_bug.cgi?id=22263
>>>>>>
>>>>>> Tested on i686 and x86-64.
>>>>>>
>>>>>> Build results of build-many-glibcs.py with --enable-static-pie with all
>>>>>> patches for static PIE applied are
>>>>>>
>>>>>> PASS: glibcs-aarch64_be-linux-gnu build
>>>>>> PASS: glibcs-aarch64-linux-gnu build
>>>>>
>>>>> i'd expect these to fail on current binutils master
>>>>>
>>>>> (linking with undefweak symbol fails now because of the issues
>>>>> listed above, i'll try to prepare a binutils patch)
>>>>>
>>>>
>>>> Do you think you can fix arm64 for glibc 2.27?
>>>>
>>>
>>> the aarch64 glibc tests pass with the pie patches and
>>> the start code fix i posted (and with a fixed bfd linker).
>>
>> Great. Linker changes look quite straight forward. I will
>> update my commit message.
>
> Here is the patch with the updated commit message.
>
> Thanks.
Static PIE works on i686, x32 and x86-64 as well as aarch64
with a patch. I will check in my patch and update
https://sourceware.org/glibc/wiki/PortStatus
next week if there no objection.
On Thu, 30 Nov 2017, H.J. Lu wrote:
> Static PIE works on i686, x32 and x86-64 as well as aarch64
> with a patch. I will check in my patch and update
>
> https://sourceware.org/glibc/wiki/PortStatus
>
> next week if there no objection.
I object to it being checked in without proper review achieving a
consensus. This is a major new feature, not in anyone's subsystem
maintainership area; it's not possibly something that could be considered
borderline obvious.
On Thu, Nov 30, 2017 at 7:28 AM, Joseph Myers <joseph@codesourcery.com> wrote:
> On Thu, 30 Nov 2017, H.J. Lu wrote:
>
>> Static PIE works on i686, x32 and x86-64 as well as aarch64
>> with a patch. I will check in my patch and update
>>
>> https://sourceware.org/glibc/wiki/PortStatus
>>
>> next week if there no objection.
>
> I object to it being checked in without proper review achieving a
> consensus. This is a major new feature, not in anyone's subsystem
> maintainership area; it's not possibly something that could be considered
> borderline obvious.
Can you help me achieve consensus on this issue? I'd like to get static PIE
into glibc 2.27.
Thanks.
On Thu, 30 Nov 2017, H.J. Lu wrote:
> Can you help me achieve consensus on this issue? I'd like to get static PIE
> into glibc 2.27.
The closest component to this work is dynamic-link, where Carlos is listed
as interested reviewer.
On Thu, Nov 30, 2017 at 8:37 AM, Joseph Myers <joseph@codesourcery.com> wrote:
> On Thu, 30 Nov 2017, H.J. Lu wrote:
>
>> Can you help me achieve consensus on this issue? I'd like to get static PIE
>> into glibc 2.27.
>
> The closest component to this work is dynamic-link, where Carlos is listed
> as interested reviewer.
>
Hi Carlos,
Here is my patch to enable static PIE:
https://sourceware.org/git/?p=glibc.git;a=commit;h=b3c9432386edbd2f57098daa6a2a63780c9d9d63
It fixed:
https://sourceware.org/bugzilla/show_bug.cgi?id=19574
I also created hjl/pie/static branch in glibc git repo. Can you take
a look at my patch?
Thanks.
On 11/30/2017 08:56 AM, H.J. Lu wrote:
> On Thu, Nov 30, 2017 at 8:37 AM, Joseph Myers <joseph@codesourcery.com> wrote:
>> On Thu, 30 Nov 2017, H.J. Lu wrote:
>>
>>> Can you help me achieve consensus on this issue? I'd like to get static PIE
>>> into glibc 2.27.
>>
>> The closest component to this work is dynamic-link, where Carlos is listed
>> as interested reviewer.
>>
>
> Hi Carlos,
>
> Here is my patch to enable static PIE:
>
> https://sourceware.org/git/?p=glibc.git;a=commit;h=b3c9432386edbd2f57098daa6a2a63780c9d9d63
>
> It fixed:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=19574
>
> I also created hjl/pie/static branch in glibc git repo. Can you take
> a look at my patch?
Yes, I'm reviewing this patch now:
https://www.sourceware.org/ml/libc-alpha/2017-11/msg00896.html
Thank you for your patience.
H.J.,
High Level:
At a high level I have no objection with the idea of static PIE executables,
it makes sense to support such things.
My only nit is that we need to do a better job of explaining to users why
they would use them and under what circumstances. To that end you have a bit
more work to do in the commit message, install.texit, and NEWS entry.
Design:
I have one design question below which around testing static non-PIE executables
in a --enable-static-pie build. See below.
Implementation:
Everything looks good except the use of firstword in +link-static-before-libc,
which I describe below. I think this is a hack and should be changed to better
represent the expected semantics and structure you are looking to support.
Thank you for your work in this area.
Look forward to a v2.
> From 7026a79c1f71f5decd135208503fd4186193ffb8 Mon Sep 17 00:00:00 2001
> From: "H.J. Lu" <hjl.tools@gmail.com>
> Date: Mon, 17 Jul 2017 08:17:32 -0700
> Subject: [PATCH] Add --enable-static-pie configure option to build static PIE
> [BZ #19574]
>
> Dynamic linker, ld.so, is a standalone program which can be loaded at
> any address. This patch adds a configure option, --enable-static-pie,
> to embed the part of ld.so in static executable to create static position
> independent executable (static PIE). A static PIE is similar to static
> executable, but can be loaded at any address without help from a dynamic
> linker. When --enable-static-pie is used to configure glibc, libc.a is
> built as PIE and all static executables, including tests, are built as
> static PIE. The resulting libc.a can be used together with GCC 8 or
> above to build static PIE with the compiler option, -static-pie. But
> GCC 8 isn't required to build glibc with --enable-static-pie. When an
> older GCC is used to build glibc with --enable-static-pie, proper input
> files are passed to linker to create static executables as static PIE,
> together with "-z text" to prevent dynamic relocations in read-only
> segments, which are allowed in static PIE.
You write "which are allowed", shouldn't that be "which are not allowed"?
The commit message must explain the following:
* Why would a user use this feature?
- What does it provide over and beyond existing static executables
* How does a user decide to use this feature?
- Should everyone use it?
- Should you use it if you care about security, and what does it cost?
Please include the answers to these questions in a the next versions
commit message.
>
> The following changes are made for static PIE:
>
> 1. Add a new function, _dl_relocate_static_pie, to:
> a. Get the run-time load address.
> b. Read the dynamic section.
> c. Perform dynamic relocations.
OK.
> Dynamic linker also performs these steps. But static PIE doesn't load
> any shared objects.
OK.
> 2. Call _dl_relocate_static_pie at entrance of LIBC_START_MAIN in
> libc.a. crt1.o, which is used to create dynamic and non-PIE static
> executables, is updated to include a dummy _dl_relocate_static_pie.
> rcrt1.o is added to create static PIE, which will link in the real
> _dl_relocate_static_pie. grcrt1.o is also added to create static PIE
> with -pg. GCC 8 has been updated to support rcrt1.o and grcrt1.o for
> static PIE.
>
> Static PIE can work on all architectures which support PIE, provided:
>
> 1. Target must support accessing of local functions without dynamic
> relocations, which is needed in start.S to call __libc_start_main with
> function addresses of __libc_csu_init, __libc_csu_fini and main. All
> functions in static PIE are local functions. If PIE start.S can't reach
> main () defined in a shared object, the code sequence:
>
> pass addess of local_main to __libc_start_main
> ...
>
> local_main:
> tail call to main via PLT
>
> can be used.
> 2. start.S is updated to check PIC instead SHARED for PIC code path and
> avoid dynamic relocation, when PIC is defined and SHARED isn't defined,
> to support static PIE. Patches are submitted for aarch64, hppa, m68k,
> microblaze and sparc.
> 3. All assembly codes are updated check PIC instead SHARED for PIC code
> path to avoid dynamic relocations in read-only sections.
> 4. All assembly codes are updated check SHARED instead PIC for static
> symbol name. A patch is submitted for tile.
> 5. elf_machine_load_address in dl-machine.h are updated to support static
> PIE. Patches are submitted for aarch64, s390 and sh.
> 6. __brk works without TLS nor dynamic relocations in read-only section
> so that it can be used by __libc_setup_tls to initializes TLS in static
> PIE.
>
> NB: When glibc is built with GCC defaulted to PIE, libc.a is compiled
> with -fPIE, regardless if --enable-static-pie is used to configure glibc.
> When glibc is configured with --enable-static-pie, libc.a is compiled
> with -fPIE, regardless wether GCC defaults to PIE or not. The same libc.a
> can be used to build both static executable and static PIE. There is no
> need for separate PIE copy of libc.a.
>
> On x86-64, the normal static sln:
>
> text data bss dec hex filename
> 625425 8284 5456 639165 9c0bd elf/sln
>
> the static PIE sln:
>
> text data bss dec hex filename
> 657626 20636 5392 683654 a6e86 elf/sln
>
> The code size is increased by 5% and the binary size is increased by 7%.
>
> Linker requirements to build glibc with --enable-static-pie:
>
> 1. Linker supports --no-dynamic-linker to remove PT_INTERP segment from
> static PIE.
> 2. Linker can create working static PIE. The x86-64 linker needs the
> fix for
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=21782
>
> The i386 linker needs to be able to convert "movl main@GOT(%ebx), %eax"
> to "leal main@GOTOFF(%ebx), %eax" if main is defined locally.
>
> Binutils 2.29 or above are OK for i686 and x86-64. But linker status for
> other targets need to be verified.
>
> 3. Linker should resolve undefined weak symbols to 0 in static PIE:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=22269
>
> 4. Many ELF backend linkers incorrectly check bfd_link_pic for TLS
> relocations, which should check bfd_link_executable instead:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=22263
>
> Tested on aarch64, i686 and x86-64.
>
> On aarch64, binutils master branch with 2 patches:
>
> https://sourceware.org/ml/binutils/2017-11/msg00455.html
> https://sourceware.org/ml/binutils/2017-11/msg00456.html
>
> applied is required.
>
> build-many-glibcs.py with --enable-static-pie with all patches for static
> PIE applied have many failures:
>
> FAIL: glibcs-alpha-linux-gnu build
>
> elf/sln is failed to link due to:
>
> assertion fail bfd/elf64-alpha.c:4125
>
> This is caused by linker bug and/or non-PIC code in PIE libc.a.
>
> FAIL: glibcs-ia64-linux-gnu build
>
> elf/sln is failed to link due to:
>
> libc.a(sched_yield.o): non-pic code with imm relocation against dynamic symbol `_dl_sysinfo'
>
> This is caused by non-PIC version of DO_CALL macro in ia64 sysdep.h. PIE
> libc.a should use PIC version of DO_CALL, except during startup in static
> PIE. An ia64 startup.h, similar to i386 startup.h, is needed to handle
> this.
>
> FAIL: glibcs-mips64el-linux-gnu-n32 build
> FAIL: glibcs-mips64el-linux-gnu-n32-nan2008 build
> FAIL: glibcs-mips64el-linux-gnu-n32-nan2008-soft build
> FAIL: glibcs-mips64el-linux-gnu-n32-soft build
> FAIL: glibcs-mips64-linux-gnu-n32 build
> FAIL: glibcs-mips64-linux-gnu-n32-nan2008 build
> FAIL: glibcs-mips64-linux-gnu-n32-nan2008-soft build
> FAIL: glibcs-mips64-linux-gnu-n32-soft build
> FAIL: glibcs-mipsel-linux-gnu build
> FAIL: glibcs-mipsel-linux-gnu-nan2008 build
> FAIL: glibcs-mipsel-linux-gnu-nan2008-soft build
> FAIL: glibcs-mipsel-linux-gnu-soft build
> FAIL: glibcs-mips-linux-gnu build
> FAIL: glibcs-mips-linux-gnu-nan2008 build
> FAIL: glibcs-mips-linux-gnu-nan2008-soft build
> FAIL: glibcs-mips-linux-gnu-soft build
>
> elf/sln is failed to link due to:
>
> crt1.o: relocation R_MIPS_HI16 against `_gp' can not be used when making a shared object; recompile with -fPIC
>
> This is caused by linker bug and/or non-PIC code in crt1.o.
>
> FAIL: glibcs-powerpc-linux-gnu build
> FAIL: glibcs-powerpc-linux-gnu-soft build
> FAIL: glibcs-powerpc-linux-gnuspe build
> FAIL: glibcs-powerpc-linux-gnuspe-e500v1 build
>
> elf/sln is failed to link due to:
>
> ld: read-only segment has dynamic relocations.
>
> This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=22264
>
> FAIL: glibcs-powerpc-linux-gnu-power4 build
>
> elf/sln is failed to link due to:
>
> findlocale.c:96:(.text+0x22c): @local call to ifunc memchr
>
> This is caused by linker bug and/or non-PIC code in PIE libc.a.
>
> FAIL: glibcs-s390-linux-gnu build
>
> elf/sln is failed to link due to:
>
> collect2: fatal error: ld terminated with signal 11 [Segmentation fault], core dumped
>
> assertion fail bfd/elflink.c:14242
>
> This is caused by linker bug and/or non-PIC code in PIE libc.a.
>
> FAIL: glibcs-sh3eb-linux-gnu build
> FAIL: glibcs-sh3-linux-gnu build
> FAIL: glibcs-sh4eb-linux-gnu build
> FAIL: glibcs-sh4eb-linux-gnu-soft build
> FAIL: glibcs-sh4-linux-gnu build
> FAIL: glibcs-sh4-linux-gnu-soft build
>
> elf/sln is failed to link due to:
>
> ld: read-only segment has dynamic relocations.
>
> This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=22263
>
> Also TLS code sequence in SH assembly syscalls in glibc doesn't match TLS
> code sequence expected by ld:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=22270
>
> FAIL: glibcs-sparc64-linux-gnu build
> FAIL: glibcs-sparcv9-linux-gnu build
> FAIL: glibcs-tilegxbe-linux-gnu build
> FAIL: glibcs-tilegxbe-linux-gnu-32 build
> FAIL: glibcs-tilegx-linux-gnu build
> FAIL: glibcs-tilegx-linux-gnu-32 build
> FAIL: glibcs-tilepro-linux-gnu build
>
> elf/sln is failed to link due to:
>
> ld: read-only segment has dynamic relocations.
>
> This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=22263
>
> [BZ #19574]
> * INSTALL: Regenerated.
> * Makeconfig (static-start-installed-name): Add the `r' prefix
> for --enable-static-pie.
> (pic-default): Updated for --enable-static-pie.
> (pie-default): New for --enable-static-pie.
> (default-pie-ldflag): Likewise.
> (+link-static-before-libc): Use the first of $(DEFAULT-LDFLAGS-$(@F))
> and $(default-pie-ldflag).
> (+prectorT): Updated for --enable-static-pie.
> (+postctorT): Likewise.
> (CFLAGS-.o): Add $(pie-default).
> (CFLAGS-.op): Likewise.
> * NEWS: Mention --enable-static-pie.
> * config.h.in (ENABLE_STATIC_PIE): New.
> * configure.ac (--enable-static-pie): New configure option.
> (have-no-dynamic-linker): New LIBC_CONFIG_VAR.
> (have-static-pie): Likewise.
> Enable static PIE if linker supports --no-dynamic-linker.
> (ENABLE_STATIC_PIE): New AC_DEFINE.
> (enable-static-pie): New LIBC_CONFIG_VAR.
> * configure: Regenerated.
> * csu/Makefile (omit-deps): Add r$(start-installed-name) for
> --enable-static-pie.
> (extra-objs): Likewise.
> (install-lib): Likewise.
> (extra-objs): Add static-reloc.o and static-reloc.os
> ($(objpfx)$(start-installed-name)): Also depend on
> $(objpfx)static-reloc.o.
> ($(objpfx)r$(start-installed-name)): New.
> ($(objpfx)g$(start-installed-name)): Also depend on
> $(objpfx)static-reloc.os.
> * csu/libc-start.c (LIBC_START_MAIN): Call _dl_relocate_static_pie
> in libc.a.
> * csu/libc-tls.c (__libc_setup_tls): Add main_map->l_addr to
> initimage.
> * csu/static-reloc.c: New file.
> * elf/Makefile (routines): Add dl-reloc-static-pie.
> (elide-routines.os): Likewise.
> * elf/dl-reloc-static-pie.c: New file.
> * elf/dl-support.c (_dl_get_dl_main_map): New function.
> * elf/dynamic-link.h (ELF_DURING_STARTUP): Also check
> STATIC_PIE_BOOTSTRAP.
> * elf/get-dynamic-info.h (elf_get_dynamic_info): Likewise.
> * gmon/Makefile (tests): Add tst-gmon-static-pie.
> (tests-static): Likewise.
> (CFLAGS-tst-gmon-static-pie.c): New.
> (CRT-tst-gmon-static-pie): Likewise.
> (tst-gmon-static-pie-ENV): Likewise.
> (tests-special): Likewise.
> ($(objpfx)tst-gmon-static-pie.out): Likewise.
> (clean-tst-gmon-static-pie-data): Likewise.
> ($(objpfx)tst-gmon-static-pie-gprof.out): Likewise.
> * gmon/tst-gmon-static-pie.c: New file.
> * manual/install.texi: Document --enable-static-pie.
> * sysdeps/generic/ldsodefs.h (_dl_relocate_static_pie): New.
> (_dl_get_dl_main_map): Likewise.
> * sysdeps/i386/configure.ac: Check if linker supports static PIE.
> * sysdeps/x86_64/configure.ac: Likewise.
> * sysdeps/i386/configure: Regenerated.
> * sysdeps/x86_64/configure: Likewise.
> ---
> INSTALL | 7 ++++
> Makeconfig | 34 ++++++++++++++++++--
> NEWS | 5 +++
> config.h.in | 3 ++
> configure | 78 +++++++++++++++++++++++++++++++++++++++++++++
> configure.ac | 29 +++++++++++++++++
> csu/Makefile | 17 ++++++++--
> csu/libc-start.c | 2 ++
> csu/libc-tls.c | 6 ++--
> csu/static-reloc.c | 26 +++++++++++++++
> elf/Makefile | 5 +--
> elf/dl-reloc-static-pie.c | 52 ++++++++++++++++++++++++++++++
> elf/dl-support.c | 11 +++++++
> elf/dynamic-link.h | 2 +-
> elf/get-dynamic-info.h | 6 ++--
> gmon/Makefile | 23 +++++++++++++
> gmon/tst-gmon-static-pie.c | 1 +
> manual/install.texi | 7 ++++
> sysdeps/generic/ldsodefs.h | 11 +++++++
> sysdeps/i386/configure | 33 +++++++++++++++++++
> sysdeps/i386/configure.ac | 23 +++++++++++++
> sysdeps/x86_64/configure | 33 +++++++++++++++++++
> sysdeps/x86_64/configure.ac | 25 +++++++++++++++
> 23 files changed, 425 insertions(+), 14 deletions(-)
> create mode 100644 csu/static-reloc.c
> create mode 100644 elf/dl-reloc-static-pie.c
> create mode 100644 gmon/tst-gmon-static-pie.c
>
> diff --git a/INSTALL b/INSTALL
> index ac8db74a0f..1beede7bae 100644
> --- a/INSTALL
> +++ b/INSTALL
> @@ -90,6 +90,13 @@ will be used, and CFLAGS sets optimization options for the compiler.
> systems support shared libraries; you need ELF support and
> (currently) the GNU linker.
>
> +'--enable-static-pie'
> + Build static executables, including tests, as position independent
> + executable (static PIE) which is similar to static executable, but
> + can be loaded at any address without help from a dynamic linker.
> + The resulting libc.a can be used with the GCC option, -static-pie,
> + which is available with GCC 8 or above, to create static PIE.
OK.
> +
> '--disable-profile'
> Don't build libraries with profiling information. You may want to
> use this option if you don't plan to do profiling.
> diff --git a/Makeconfig b/Makeconfig
> index 1346109ac0..62a0c30498 100644
> --- a/Makeconfig
> +++ b/Makeconfig
> @@ -352,6 +352,12 @@ ifndef static-start-installed-name
> static-start-installed-name = $(start-installed-name)
> endif
>
> +ifeq (yes,$(enable-static-pie))
> +# Link with rcrt1.o, instead of crt1.o, to call _dl_relocate_static_pie
> +# to relocate static PIE.
> +static-start-installed-name := r$(static-start-installed-name)
> +endif
OK.
> +
> ifeq (yesyes,$(build-shared)$(have-z-combreloc))
> combreloc-LDFLAGS = -Wl,-z,combreloc
> LDFLAGS.so += $(combreloc-LDFLAGS)
> @@ -371,6 +377,20 @@ LDFLAGS.so += $(hashstyle-LDFLAGS)
> LDFLAGS-rtld += $(hashstyle-LDFLAGS)
> endif
>
> +ifeq (yes,$(enable-static-pie))
> +pic-default = -DPIC
> +# Compile libc.a and libc_p.a with -fPIE/-fpie for static PIE.
> +pie-default = $(pie-ccflag)
> +ifeq (yes,$(have-static-pie))
> +default-pie-ldflag = -static-pie
> +else
> +# Static PIE can't have dynamic relocations in read-only segments since
> +# static PIE is mapped into memory by kernel. --eh-frame-hdr is needed
> +# for PIE to support exception.
> +default-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
OK.
> +endif
> +endif
> +
> # If lazy relocations are disabled, add the -z now flag. Use
> # LDFLAGS-lib.so instead of LDFLAGS.so, to avoid adding the flag to
> # test modules.
> @@ -420,7 +440,7 @@ endif
> # Command for statically linking programs with the C library.
> ifndef +link-static
> +link-static-before-libc = $(CC) -nostdlib -nostartfiles -static -o $@ \
> - $(DEFAULT-LDFLAGS-$(@F)) \
> + $(firstword $(DEFAULT-LDFLAGS-$(@F)) $(default-pie-ldflag)) \
Is the use of firstword here just a hack to put $(no-pie-ldflag) first so
you can override it with the subsequent $(default-pie-ldflag)?
It is not a robust design to use firstword here because it implies that the
DEFAUTL-LDFLAGS-$(@F) has some structure that we are not documenting.
I would like to see this done some other way. My preference would be for a new
value other than DEFAULT-LDFLAGS to control the PIE-ness of the built progarm.
> $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \
> $(firstword $(CRT-$(@F)) $(csu-objpfx)$(static-start-installed-name)) \
> $(+preinit) $(+prectorT) \
> @@ -637,8 +657,14 @@ endif
> +prectorS = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtbeginS.o`
> +postctorS = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtendS.o`
> # Variants of the two previous definitions for statically linking programs.
> +ifeq (yes,$(enable-static-pie))
> +# Static PIE must use PIE variants.
> ++prectorT = $(+prectorS)
> ++postctorT = $(+postctorS)
OK.
> +else
> +prectorT = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtbeginT.o`
> +postctorT = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtend.o`
> +endif
OK.
> csu-objpfx = $(common-objpfx)csu/
> elf-objpfx = $(common-objpfx)elf/
>
> @@ -959,7 +985,8 @@ libtypes = $(foreach o,$(object-suffixes-for-libc),$(libtype$o))
> all-object-suffixes := .o .os .oS
> object-suffixes :=
> CPPFLAGS-.o = $(pic-default)
> -CFLAGS-.o = $(filter %frame-pointer,$(+cflags))
> +# libc.a must be compiled with -fPIE/-fpie for static PIE.
> +CFLAGS-.o = $(filter %frame-pointer,$(+cflags)) $(pie-default)
OK.
> libtype.o := lib%.a
> object-suffixes += .o
> ifeq (yes,$(build-shared))
> @@ -984,7 +1011,8 @@ ifeq (yes,$(build-profile))
> all-object-suffixes += .op
> object-suffixes += .op
> CPPFLAGS-.op = -DPROF $(pic-default)
> -CFLAGS-.op = -pg
> +# libc_p.a must be compiled with -fPIE/-fpie for static PIE.
> +CFLAGS-.op = -pg $(pie-default)
OK.
> libtype.op = lib%_p.a
> endif
>
> diff --git a/NEWS b/NEWS
> index ab14d1eb1b..61598be94d 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -9,6 +9,11 @@ Version 2.27
>
> Major new features:
>
> +* Add --enable-static-pie configure option to build static PIE. The
> + resulting libc.a can be used with the GCC option, -static-pie, which
> + is available with GCC 8 or above, to create static position independent
> + executable (static PIE).
> +
The description of a new configure option is relevant only to INSTALL.
We must explain when users would use this feature and why. NEWS entries are
user facing and must explain the function of the new feature. Does it improve
security for static binaries? Should users switch to using them instead of
normal static binaries?
Lastly, we must explain which machines are supported in this initial release
of the feature. Only x86_64? You need not check all machines, other maintainers
can check and adjust the NEWS entry, but we have to commit to at least one
machine supporting this feature, which I assume is x86_64.
For example:
* The GNU C Library can now be compiled with support for building static
PIE executables (See --enable-static-pie in INSTALL). These static PIE
exectuables are like static executables but can be loaded at any address
and provide additional security hardening benefits at the cost of some
memory and performance. When the library is built with --enable-static-pie
the resulting libc.a is usable with GCC 8 and above to create static PIE
executables using the GCC option '-static-pie'. This feature is currently
supported on x86_64.
> * Optimized x86-64 asin, atan2, exp, expf, log, pow, atan, sin and tan
> with FMA, contributed by Arjan van de Ven and H.J. Lu from Intel.
>
> diff --git a/config.h.in b/config.h.in
> index c140ff3ecb..f7db916711 100644
> --- a/config.h.in
> +++ b/config.h.in
> @@ -244,6 +244,9 @@
> /* Build glibc with tunables support. */
> #define HAVE_TUNABLES 0
>
> +/* Define if static PIE is enabled. */
> +#define ENABLE_STATIC_PIE 0
> +
OK. Architecture independent feature, which is OK to go in config.h (we're
trying to get rid of any architecture specific entries).
> /* Some compiler options may now allow to use ebp in __asm__ (used mainly
> in i386 6 argument syscall issue). */
> #define CAN_USE_REGISTER_ASM_EBP 0
[snip configure]
> diff --git a/configure.ac b/configure.ac
> index 8ebc490a55..ae219f8fe0 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -176,6 +176,11 @@ AC_ARG_ENABLE([profile],
> [build profiled library @<:@default=no@:>@]),
> [profile=$enableval],
> [profile=no])
> +AC_ARG_ENABLE([static-pie],
> + AC_HELP_STRING([--enable-static-pie],
> + [build static executables as PIE @<:@default=no@:>@]),
This does 2 things:
* It enables support for building static PIE executables.
* It builds all static binaries and tests in the testsuite as static PIE executables.
It should say that e.g.
"Enable static PIE executable support and use it in the testsuite."
I understand the desire to use such a functionality to test static PIE executables
by converting the entire testsuite to use them, but we still need to test non-PIE
static executables? How are we still doing that after this change?
How are we testing non-PIE static executables after this change?
> + [static_pie=$enableval],
> + [static_pie=no])
OK.
> AC_ARG_ENABLE([timezone-tools],
> AC_HELP_STRING([--disable-timezone-tools],
> [do not install timezone tools @<:@default=install@:>@]),
> @@ -1281,6 +1286,19 @@ LIBC_LINKER_FEATURE([-z execstack], [-Wl,-z,execstack],
> [libc_cv_z_execstack=yes], [libc_cv_z_execstack=no])
> AC_SUBST(libc_cv_z_execstack)
>
> +LIBC_LINKER_FEATURE([--no-dynamic-linker],
> + [-Wl,--no-dynamic-linker],
> + [libc_cv_no_dynamic_linker=yes],
> + [libc_cv_no_dynamic_linker=no])
> +LIBC_CONFIG_VAR([have-no-dynamic-linker], [$libc_cv_no_dynamic_linker])
OK.
> +
> +AC_CACHE_CHECK(for -static-pie, libc_cv_static_pie, [dnl
> +LIBC_TRY_CC_OPTION([-static-pie],
> + [libc_cv_static_pie=yes],
> + [libc_cv_static_pie=no])
> +])
> +LIBC_CONFIG_VAR([have-static-pie], [$libc_cv_static_pie])
OK.
> +
> AC_CACHE_CHECK(for -fpie, libc_cv_fpie, [dnl
> LIBC_TRY_CC_OPTION([-fpie], [libc_cv_fpie=yes], [libc_cv_fpie=no])
> ])
> @@ -1788,6 +1806,17 @@ AC_SUBST(libc_cv_pie_default)
> libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory`
> AC_SUBST(libc_cv_multidir)
>
> +if test "$static_pie" = yes; then
> + # The linker must support --no-dynamic-linker.
> + if test "$libc_cv_no_dynamic_linker" != yes; then
> + AC_MSG_ERROR([linker support for --no-dynamic-linker needed])
> + fi
> + # Default to PIE.
> + libc_cv_pie_default=yes
> + AC_DEFINE(ENABLE_STATIC_PIE)
> +fi
> +LIBC_CONFIG_VAR([enable-static-pie], [$static_pie])
OK.
> +
> AC_SUBST(profile)
> AC_SUBST(static_nss)
>
> diff --git a/csu/Makefile b/csu/Makefile
> index e42a32b3eb..e8ff1ec257 100644
> --- a/csu/Makefile
> +++ b/csu/Makefile
> @@ -37,7 +37,8 @@ extra-objs = start.o \
> S$(start-installed-name)
> omit-deps = $(patsubst %.o,%,$(start-installed-name) g$(start-installed-name) \
> b$(start-installed-name) $(csu-dummies) \
> - S$(start-installed-name))
> + S$(start-installed-name) \
> + r$(start-installed-name))
OK.
> install-lib = $(start-installed-name) g$(start-installed-name) $(csu-dummies)
>
> # No tests are allowed in the csu/ subdirectory because the startup
> @@ -55,6 +56,10 @@ extra-objs += gmon-start.o
> endif
> install-lib += S$(start-installed-name)
> generated += start.os
> +ifeq (yes,$(enable-static-pie))
> +extra-objs += r$(start-installed-name)
> +install-lib += r$(start-installed-name)
> +endif
OK.
> else
> extra-objs += gmon-start.o
> endif
> @@ -82,7 +87,10 @@ multilib-extra-objs = $(addprefix $(multidir)/, $(install-lib))
> extra-objs += $(multilib-extra-objs)
> endif
>
> -extra-objs += abi-note.o init.o
> +extra-objs += abi-note.o init.o static-reloc.o
> +ifeq (yes,$(build-shared))
> +extra-objs += static-reloc.os
> +endif
OK.
> asm-CPPFLAGS += -I$(objpfx).
>
> # Enable unwinding so backtrace unwinds to __libc_start_main
> @@ -101,6 +109,9 @@ ifndef start-installed-name-rule
> # We link the ELF startfile along with a SHT_NOTE section indicating
> # the kernel ABI the binaries linked with this library will require.
> $(objpfx)$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
> + $(objpfx)init.o $(objpfx)static-reloc.o
> + $(link-relocatable)
> +$(objpfx)r$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
OK.
> $(objpfx)init.o
> $(link-relocatable)
> $(objpfx)S$(start-installed-name): $(objpfx)start.os $(objpfx)abi-note.o \
> @@ -113,7 +124,7 @@ endif
> # to turn on profiling code at startup.
> ifeq (yes,$(build-shared))
> $(objpfx)g$(start-installed-name): \
> - $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os
> + $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os $(objpfx)static-reloc.os
OK.
> $(link-relocatable)
> ifneq ($(start-installed-name),$(static-start-installed-name))
> $(objpfx)g$(static-start-installed-name): \
> diff --git a/csu/libc-start.c b/csu/libc-start.c
> index 24c63be02f..34dd125260 100644
> --- a/csu/libc-start.c
> +++ b/csu/libc-start.c
> @@ -141,6 +141,8 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
> __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
>
> #ifndef SHARED
> + _dl_relocate_static_pie ();
OK.
> +
> char **ev = &argv[argc + 1];
>
> __environ = ev;
> diff --git a/csu/libc-tls.c b/csu/libc-tls.c
> index 00138eb43a..1f8ddaf543 100644
> --- a/csu/libc-tls.c
> +++ b/csu/libc-tls.c
> @@ -114,6 +114,8 @@ __libc_setup_tls (void)
> size_t tcb_offset;
> const ElfW(Phdr) *phdr;
>
> + struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
OK.
> +
> /* Look through the TLS segment if there is any. */
> if (_dl_phdr != NULL)
> for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)
> @@ -122,7 +124,7 @@ __libc_setup_tls (void)
> /* Remember the values we need. */
> memsz = phdr->p_memsz;
> filesz = phdr->p_filesz;
> - initimage = (void *) phdr->p_vaddr;
> + initimage = (void *) phdr->p_vaddr + main_map->l_addr;
OK.
> align = phdr->p_align;
> if (phdr->p_align > max_align)
> max_align = phdr->p_align;
> @@ -163,8 +165,6 @@ __libc_setup_tls (void)
> _dl_static_dtv[0].counter = (sizeof (_dl_static_dtv) / sizeof (_dl_static_dtv[0])) - 2;
> // _dl_static_dtv[1].counter = 0; would be needed if not already done
>
> - struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
> -
> /* Initialize the TLS block. */
> #if TLS_TCB_AT_TP
> _dl_static_dtv[2].pointer.val = ((char *) tlsblock + tcb_offset
> diff --git a/csu/static-reloc.c b/csu/static-reloc.c
> new file mode 100644
> index 0000000000..37be72c8ea
> --- /dev/null
> +++ b/csu/static-reloc.c
> @@ -0,0 +1,26 @@
> +/* Special startup support for non-PIE static executables.
> + Copyright (C) 2017 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library 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
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#if ENABLE_STATIC_PIE
> +#include <ldsodefs.h>
> +
> +void
> +_dl_relocate_static_pie (void)
> +{
> +}
> +#endif
OK.
> diff --git a/elf/Makefile b/elf/Makefile
> index a31fb72498..cb035e63aa 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -24,7 +24,8 @@ include ../Makeconfig
> headers = elf.h bits/elfclass.h link.h bits/link.h
> routines = $(all-dl-routines) dl-support dl-iteratephdr \
> dl-addr dl-addr-obj enbl-secure dl-profstub \
> - dl-origin dl-libc dl-sym dl-sysdep dl-error
> + dl-origin dl-libc dl-sym dl-sysdep dl-error \
> + dl-reloc-static-pie
OK.
>
> # The core dynamic linking functions are in libc for the static and
> # profiled libraries.
> @@ -52,7 +53,7 @@ endif
> all-dl-routines = $(dl-routines) $(sysdep-dl-routines)
> # But they are absent from the shared libc, because that code is in ld.so.
> elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \
> - dl-sysdep dl-exception
> + dl-sysdep dl-exception dl-reloc-static-pie
OK.
> shared-only-routines += dl-caller
>
> # ld.so uses those routines, plus some special stuff for being the program
> diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c
> new file mode 100644
> index 0000000000..6e43aea76a
> --- /dev/null
> +++ b/elf/dl-reloc-static-pie.c
> @@ -0,0 +1,52 @@
> +/* Support for relocating static PIE.
> + Copyright (C) 2017 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library 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
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#if ENABLE_STATIC_PIE
> +#include <unistd.h>
> +#include <ldsodefs.h>
> +#include "dynamic-link.h"
> +
> +/* Relocate static executable with PIE. */
> +
> +void
> +_dl_relocate_static_pie (void)
> +{
> + struct link_map *main_map = _dl_get_dl_main_map ();
> +
> +# define STATIC_PIE_BOOTSTRAP
> +# define BOOTSTRAP_MAP (main_map)
> +# define RESOLVE_MAP(sym, version, flags) BOOTSTRAP_MAP
> +# include "dynamic-link.h"
> +
> + /* Figure out the run-time load address of static PIE. */
> + main_map->l_addr = elf_machine_load_address ();
OK.
> +
> + /* Read our own dynamic section and fill in the info array. */
> + main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ());
> + elf_get_dynamic_info (main_map, NULL);
OK.
> +
> +# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
> + ELF_MACHINE_BEFORE_RTLD_RELOC (main_map->l_info);
> +# endif
> +
> + /* Relocate ourselves so we can do normal function calls and
> + data access using the global offset table. */
> + ELF_DYNAMIC_RELOCATE (main_map, 0, 0, 0);
> + main_map->l_relocated = 1;
OK.
> +}
> +#endif
> diff --git a/elf/dl-support.c b/elf/dl-support.c
> index 235d3a7f46..b9fc1a66fe 100644
> --- a/elf/dl-support.c
> +++ b/elf/dl-support.c
> @@ -385,3 +385,14 @@ _dl_non_dynamic_init (void)
> #ifdef DL_SYSINFO_IMPLEMENTATION
> DL_SYSINFO_IMPLEMENTATION
> #endif
> +
> +#if ENABLE_STATIC_PIE
> +/* Since relocation to hidden _dl_main_map causes relocation overflow on
> + aarch64, a function is used to get the address of _dl_main_map. */
> +
> +struct link_map *
> +_dl_get_dl_main_map (void)
> +{
> + return &_dl_main_map;
> +}
OK.
> +#endif
> diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
> index ebea7567cd..6278649711 100644
> --- a/elf/dynamic-link.h
> +++ b/elf/dynamic-link.h
> @@ -94,7 +94,7 @@ elf_machine_lazy_rel (struct link_map *map,
>
> #ifdef RESOLVE_MAP
>
> -# ifdef RTLD_BOOTSTRAP
> +# if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP
OK.
> # define ELF_DURING_STARTUP (1)
> # else
> # define ELF_DURING_STARTUP (0)
> diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h
> index 7525c3a5b2..eb26d23649 100644
> --- a/elf/get-dynamic-info.h
> +++ b/elf/get-dynamic-info.h
> @@ -38,7 +38,7 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
> typedef Elf64_Xword d_tag_utype;
> #endif
>
> -#ifndef RTLD_BOOTSTRAP
> +#if !defined RTLD_BOOTSTRAP && !defined STATIC_PIE_BOOTSTRAP
OK.
> if (dyn == NULL)
> return;
> #endif
> @@ -139,9 +139,11 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
> /* Only the bind now flags are allowed. */
> assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
> || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
> + /* Flags must not be set for ld.so. */
> assert (info[DT_FLAGS] == NULL
> || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
OK.
> - /* Flags must not be set for ld.so. */
> +#endif
> +#if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP
> assert (info[DT_RUNPATH] == NULL);
> assert (info[DT_RPATH] == NULL);
> #else
> diff --git a/gmon/Makefile b/gmon/Makefile
> index 89ab3fc7da..f83fcc9d71 100644
> --- a/gmon/Makefile
> +++ b/gmon/Makefile
> @@ -39,6 +39,10 @@ tests-static += tst-gmon-static
> ifeq (yesyes,$(have-fpie)$(build-shared))
> tests += tst-gmon-pie
> tests-pie += tst-gmon-pie
> +ifeq (yes,$(enable-static-pie))
> +tests += tst-gmon-static-pie
> +tests-static += tst-gmon-static-pie
OK.
> +endif
> endif
>
> # The mcount code won't work without a frame pointer.
> @@ -67,6 +71,15 @@ ifeq ($(run-built-tests),yes)
> tests-special += $(objpfx)tst-gmon-pie-gprof.out
> endif
>
> +ifeq (yes,$(enable-static-pie))
> +CFLAGS-tst-gmon-static-pie.c := $(PIE-ccflag) -fno-omit-frame-pointer -pg
> +CRT-tst-gmon-static-pie := $(csu-objpfx)grcrt1.o
> +tst-gmon-static-pie-ENV := GMON_OUT_PREFIX=$(objpfx)tst-gmon-static-pie.data
> +ifeq ($(run-built-tests),yes)
> +tests-special += $(objpfx)tst-gmon-static-pie-gprof.out
> +endif
> +endif
OK.
> +
>
> include ../Rules
>
> @@ -111,3 +124,13 @@ clean-tst-gmon-pie-data:
> $(objpfx)tst-gmon-pie-gprof.out: tst-gmon-gprof.sh $(objpfx)tst-gmon-pie.out
> $(SHELL) $< $(GPROF) $(objpfx)tst-gmon-pie $(objpfx)tst-gmon-pie.data.* > $@; \
> $(evaluate-test)
> +
> +$(objpfx)tst-gmon-static-pie.out: clean-tst-gmon-static-pie-data
> +clean-tst-gmon-static-pie-data:
> + rm -f $(objpfx)tst-gmon-static-pie.data.*
> +
> +$(objpfx)tst-gmon-static-pie-gprof.out: tst-gmon-static-gprof.sh \
> + $(objpfx)tst-gmon-static-pie.out
> + $(SHELL) $< $(GPROF) $(objpfx)tst-gmon-static-pie \
> + $(objpfx)tst-gmon-static-pie.data.* > $@; \
> + $(evaluate-test)
OK.
> diff --git a/gmon/tst-gmon-static-pie.c b/gmon/tst-gmon-static-pie.c
> new file mode 100644
> index 0000000000..1eef2583b6
> --- /dev/null
> +++ b/gmon/tst-gmon-static-pie.c
> @@ -0,0 +1 @@
> +#include "tst-gmon.c"
> diff --git a/manual/install.texi b/manual/install.texi
> index f1fa28c937..86193ade3f 100644
> --- a/manual/install.texi
> +++ b/manual/install.texi
> @@ -120,6 +120,13 @@ Don't build shared libraries even if it is possible. Not all systems
> support shared libraries; you need ELF support and (currently) the GNU
> linker.
>
> +@item --enable-static-pie
This should be rewritten to explain the feature that it enables first,
and then the ancilliary benefits like turning it on in the testsuite.
> +Build static executables, including tests, as position independent
> +executable (static PIE) which is similar to static executable, but can
> +be loaded at any address without help from a dynamic linker. The
> +resulting libc.a can be used with the GCC option, -static-pie, which
> +is available with GCC 8 or above, to create static PIE.
> +
> @item --disable-profile
> Don't build libraries with profiling information. You may want to use
> this option if you don't plan to do profiling.
> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
> index 52a792a597..af89f5eeb4 100644
> --- a/sysdeps/generic/ldsodefs.h
> +++ b/sysdeps/generic/ldsodefs.h
> @@ -1051,6 +1051,17 @@ extern void _dl_determine_tlsoffset (void) attribute_hidden;
> stack protector, among other things). */
> void __libc_setup_tls (void);
>
> +# if ENABLE_STATIC_PIE
> +/* Relocate static executable with PIE. */
> +extern void _dl_relocate_static_pie (void) attribute_hidden;
> +
> +/* Get a pointer to _dl_main_map. */
> +extern struct link_map * _dl_get_dl_main_map (void)
> + __attribute__ ((visibility ("hidden")));
> +# else
> +# define _dl_relocate_static_pie()
> +# endif
> +
> /* Initialization of libpthread for statically linked applications.
> If libpthread is not linked in, this is an empty function. */
> void __pthread_initialize_minimal (void) weak_function;
> diff --git a/sysdeps/i386/configure b/sysdeps/i386/configure
> index 4cf968d8bc..90c63caf35 100644
[snip regenerated sysdeps/i386/configure]
> diff --git a/sysdeps/i386/configure.ac b/sysdeps/i386/configure.ac
> index b598b120bc..6d2068d2b3 100644
> --- a/sysdeps/i386/configure.ac
> +++ b/sysdeps/i386/configure.ac
> @@ -30,6 +30,29 @@ LIBC_COMPILER_BUILTIN_INLINED(
> *** Please use host i786, i686, i586, or i486.
> *** For example: /source/glibc/configure CFLAGS='-O2 -march=i686' ...])])
>
> +dnl Check if linker can convert "movl main@GOT(%ebx), %eax" to
> +dnl "leal main@GOTOFF(%ebx), %eax" for static PIE.
> +if test "$static_pie" = yes; then
> + AC_CACHE_CHECK(for linker static PIE support, libc_cv_ld_static_pie, [dnl
> +cat > conftest.s <<\EOF
> + .text
> + .global _start
> +_start:
> + movl _start@GOT(%ebx), %eax
> +EOF
> + libc_cv_pie_option="-Wl,-pie"
> + libc_cv_ld_static_pie=no
> + if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&AS_MESSAGE_LOG_FD); then
> + if $READELF -r conftest | grep 'There are no relocations in this file.' > /dev/null; then
> + libc_cv_ld_static_pie=yes
> + fi
> + fi
> +rm -f conftest*])
> + if test "$libc_cv_ld_static_pie" != yes; then
> + AC_MSG_ERROR([linker support for static PIE needed])
OK.
> + fi
> +fi
> +
> dnl Check whether asm supports Intel MPX
> AC_CACHE_CHECK(for Intel MPX support, libc_cv_asm_mpx, [dnl
> cat > conftest.s <<\EOF
[snip regenerated sysdeps/x86_64/configure]
On Thu, 30 Nov 2017, Carlos O'Donell wrote:
> > FAIL: glibcs-mips64el-linux-gnu-n32 build
> > FAIL: glibcs-mips64el-linux-gnu-n32-nan2008 build
> > FAIL: glibcs-mips64el-linux-gnu-n32-nan2008-soft build
> > FAIL: glibcs-mips64el-linux-gnu-n32-soft build
> > FAIL: glibcs-mips64-linux-gnu-n32 build
> > FAIL: glibcs-mips64-linux-gnu-n32-nan2008 build
> > FAIL: glibcs-mips64-linux-gnu-n32-nan2008-soft build
> > FAIL: glibcs-mips64-linux-gnu-n32-soft build
> > FAIL: glibcs-mipsel-linux-gnu build
> > FAIL: glibcs-mipsel-linux-gnu-nan2008 build
> > FAIL: glibcs-mipsel-linux-gnu-nan2008-soft build
> > FAIL: glibcs-mipsel-linux-gnu-soft build
> > FAIL: glibcs-mips-linux-gnu build
> > FAIL: glibcs-mips-linux-gnu-nan2008 build
> > FAIL: glibcs-mips-linux-gnu-nan2008-soft build
> > FAIL: glibcs-mips-linux-gnu-soft build
> >
> > elf/sln is failed to link due to:
> >
> > crt1.o: relocation R_MIPS_HI16 against `_gp' can not be used when making a shared object; recompile with -fPIC
> >
> > This is caused by linker bug and/or non-PIC code in crt1.o.
Or likely a bug in the `make' recipe used to link `sln' -- Scrt1.o has to
be chosen instead for PIE links and the GCC driver gets it right, however
we use `-nostartfiles' and link in the bits by hand.
Maciej
On Thu, Nov 30, 2017 at 3:31 PM, Maciej W. Rozycki <macro@mips.com> wrote:
> On Thu, 30 Nov 2017, H.J. Lu wrote:
>
>> > Or likely a bug in the `make' recipe used to link `sln' -- Scrt1.o has to
>> > be chosen instead for PIE links and the GCC driver gets it right, however
>> > we use `-nostartfiles' and link in the bits by hand.
>>
>> My current patch links rcrt1.o for static PIE. I got
>>
>> mips64-glibc-linux-gnu-gcc -mabi=32 -nostdlib -nostartfiles -static -o
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/elf/sln
>> -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/csu/rcrt1.o
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/csu/crti.o
>> `mips64-glibc-linux-gnu-gcc -mabi=32 --print-file-name=crtbeginS.o`
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/elf/sln.o
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/elf/static-stubs.o
>> -Wl,--start-group
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a
>> -lgcc -Wl,--end-group `mips64-glibc-linux-gnu-gcc -mabi=32
>> --print-file-name=crtendS.o`
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/csu/crtn.o
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/csu/rcrt1.o:
>> relocation R_MIPS_HI16 against `_gp' can not be used when making a
>> shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(bsd-_setjmp.o):
>> relocation R_MIPS_26 against `__sigsetjmp' can not be used when making
>> a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(sched_yield.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(symlink.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(unlink.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(munmap.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(mprotect.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(madvise.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(mremap.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(sysinfo.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(sysdep.o):
>> relocation R_MIPS_26 against `__errno_location' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(setjmp.o):
>> relocation R_MIPS_26 against `__sigsetjmp_aux' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(uname.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(prctl.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> /export/ssd/git/toolchain/install/compilers/mips64-linux-gnu/bin/../lib/gcc/mips64-glibc-linux-gnu/7.2.1/../../../../mips64-glibc-linux-gnu/bin/ld:
>> /export/gnu/import/git/toolchain/build/glibcs/mips-linux-gnu/glibc/libc.a(setitimer.o):
>> relocation R_MIPS_26 against `__syscall_error' can not be used when
>> making a shared object; recompile with -fPIC
>> collect2: error: ld returned 1 exit status
>
> I don't know what rcrt1.o is, this is the first time I see it mentioned.
See:
https://gcc.gnu.org/ml/gcc-patches/2017-11/msg00247.html
> However overall all these MIPS relocations are strictly non-PIC ones, so
> clearly this code has not been correctly built.
That is MIPS specific issue. It could be bfd_link_pic vs bfd_link_executable
in MIPS linker backend.
> AFAICT you need to pass -DPIC to GCC when assembling sysdeps/mips/start.S
> to get a position-independent intermediate object. The same applies to
> our other MIPS assembly sources.
Everything is compiled with -fPIE -DPIC:
+ifeq (yes,$(enable-static-pie))
+pic-default = -DPIC
+pie-default = $(pie-ccflag)
+ifeq (yes,$(have-static-pie))
+default-pie-ldflag = -static-pie
+else
+default-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
+endif
+endif
On Thu, 30 Nov 2017, H.J. Lu wrote:
> > However overall all these MIPS relocations are strictly non-PIC ones, so
> > clearly this code has not been correctly built.
>
> That is MIPS specific issue. It could be bfd_link_pic vs bfd_link_executable
> in MIPS linker backend.
Well, these relocations are produced by GAS, which obviously has nothing
to do with linking. You need to find a way for them not to be produced in
the first place, as they are not valid in a PIE executable link.
> > AFAICT you need to pass -DPIC to GCC when assembling sysdeps/mips/start.S
> > to get a position-independent intermediate object. The same applies to
> > our other MIPS assembly sources.
>
> Everything is compiled with -fPIE -DPIC:
>
> +ifeq (yes,$(enable-static-pie))
> +pic-default = -DPIC
> +pie-default = $(pie-ccflag)
> +ifeq (yes,$(have-static-pie))
> +default-pie-ldflag = -static-pie
> +else
> +default-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
> +endif
> +endif
Well, that doesn't prove that these options actually make it to the GCC
invocation line for say rcrt1.o. Quoting the actual line for rcrt1.o from
a build log would be more useful.
Maciej
From 7026a79c1f71f5decd135208503fd4186193ffb8 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Mon, 17 Jul 2017 08:17:32 -0700
Subject: [PATCH] Add --enable-static-pie configure option to build static PIE
[BZ #19574]
Dynamic linker, ld.so, is a standalone program which can be loaded at
any address. This patch adds a configure option, --enable-static-pie,
to embed the part of ld.so in static executable to create static position
independent executable (static PIE). A static PIE is similar to static
executable, but can be loaded at any address without help from a dynamic
linker. When --enable-static-pie is used to configure glibc, libc.a is
built as PIE and all static executables, including tests, are built as
static PIE. The resulting libc.a can be used together with GCC 8 or
above to build static PIE with the compiler option, -static-pie. But
GCC 8 isn't required to build glibc with --enable-static-pie. When an
older GCC is used to build glibc with --enable-static-pie, proper input
files are passed to linker to create static executables as static PIE,
together with "-z text" to prevent dynamic relocations in read-only
segments, which are allowed in static PIE.
The following changes are made for static PIE:
1. Add a new function, _dl_relocate_static_pie, to:
a. Get the run-time load address.
b. Read the dynamic section.
c. Perform dynamic relocations.
Dynamic linker also performs these steps. But static PIE doesn't load
any shared objects.
2. Call _dl_relocate_static_pie at entrance of LIBC_START_MAIN in
libc.a. crt1.o, which is used to create dynamic and non-PIE static
executables, is updated to include a dummy _dl_relocate_static_pie.
rcrt1.o is added to create static PIE, which will link in the real
_dl_relocate_static_pie. grcrt1.o is also added to create static PIE
with -pg. GCC 8 has been updated to support rcrt1.o and grcrt1.o for
static PIE.
Static PIE can work on all architectures which support PIE, provided:
1. Target must support accessing of local functions without dynamic
relocations, which is needed in start.S to call __libc_start_main with
function addresses of __libc_csu_init, __libc_csu_fini and main. All
functions in static PIE are local functions. If PIE start.S can't reach
main () defined in a shared object, the code sequence:
pass addess of local_main to __libc_start_main
...
local_main:
tail call to main via PLT
can be used.
2. start.S is updated to check PIC instead SHARED for PIC code path and
avoid dynamic relocation, when PIC is defined and SHARED isn't defined,
to support static PIE. Patches are submitted for aarch64, hppa, m68k,
microblaze and sparc.
3. All assembly codes are updated check PIC instead SHARED for PIC code
path to avoid dynamic relocations in read-only sections.
4. All assembly codes are updated check SHARED instead PIC for static
symbol name. A patch is submitted for tile.
5. elf_machine_load_address in dl-machine.h are updated to support static
PIE. Patches are submitted for aarch64, s390 and sh.
6. __brk works without TLS nor dynamic relocations in read-only section
so that it can be used by __libc_setup_tls to initializes TLS in static
PIE.
NB: When glibc is built with GCC defaulted to PIE, libc.a is compiled
with -fPIE, regardless if --enable-static-pie is used to configure glibc.
When glibc is configured with --enable-static-pie, libc.a is compiled
with -fPIE, regardless wether GCC defaults to PIE or not. The same libc.a
can be used to build both static executable and static PIE. There is no
need for separate PIE copy of libc.a.
On x86-64, the normal static sln:
text data bss dec hex filename
625425 8284 5456 639165 9c0bd elf/sln
the static PIE sln:
text data bss dec hex filename
657626 20636 5392 683654 a6e86 elf/sln
The code size is increased by 5% and the binary size is increased by 7%.
Linker requirements to build glibc with --enable-static-pie:
1. Linker supports --no-dynamic-linker to remove PT_INTERP segment from
static PIE.
2. Linker can create working static PIE. The x86-64 linker needs the
fix for
https://sourceware.org/bugzilla/show_bug.cgi?id=21782
The i386 linker needs to be able to convert "movl main@GOT(%ebx), %eax"
to "leal main@GOTOFF(%ebx), %eax" if main is defined locally.
Binutils 2.29 or above are OK for i686 and x86-64. But linker status for
other targets need to be verified.
3. Linker should resolve undefined weak symbols to 0 in static PIE:
https://sourceware.org/bugzilla/show_bug.cgi?id=22269
4. Many ELF backend linkers incorrectly check bfd_link_pic for TLS
relocations, which should check bfd_link_executable instead:
https://sourceware.org/bugzilla/show_bug.cgi?id=22263
Tested on aarch64, i686 and x86-64.
On aarch64, binutils master branch with 2 patches:
https://sourceware.org/ml/binutils/2017-11/msg00455.html
https://sourceware.org/ml/binutils/2017-11/msg00456.html
applied is required.
build-many-glibcs.py with --enable-static-pie with all patches for static
PIE applied have many failures:
FAIL: glibcs-alpha-linux-gnu build
elf/sln is failed to link due to:
assertion fail bfd/elf64-alpha.c:4125
This is caused by linker bug and/or non-PIC code in PIE libc.a.
FAIL: glibcs-ia64-linux-gnu build
elf/sln is failed to link due to:
libc.a(sched_yield.o): non-pic code with imm relocation against dynamic symbol `_dl_sysinfo'
This is caused by non-PIC version of DO_CALL macro in ia64 sysdep.h. PIE
libc.a should use PIC version of DO_CALL, except during startup in static
PIE. An ia64 startup.h, similar to i386 startup.h, is needed to handle
this.
FAIL: glibcs-mips64el-linux-gnu-n32 build
FAIL: glibcs-mips64el-linux-gnu-n32-nan2008 build
FAIL: glibcs-mips64el-linux-gnu-n32-nan2008-soft build
FAIL: glibcs-mips64el-linux-gnu-n32-soft build
FAIL: glibcs-mips64-linux-gnu-n32 build
FAIL: glibcs-mips64-linux-gnu-n32-nan2008 build
FAIL: glibcs-mips64-linux-gnu-n32-nan2008-soft build
FAIL: glibcs-mips64-linux-gnu-n32-soft build
FAIL: glibcs-mipsel-linux-gnu build
FAIL: glibcs-mipsel-linux-gnu-nan2008 build
FAIL: glibcs-mipsel-linux-gnu-nan2008-soft build
FAIL: glibcs-mipsel-linux-gnu-soft build
FAIL: glibcs-mips-linux-gnu build
FAIL: glibcs-mips-linux-gnu-nan2008 build
FAIL: glibcs-mips-linux-gnu-nan2008-soft build
FAIL: glibcs-mips-linux-gnu-soft build
elf/sln is failed to link due to:
crt1.o: relocation R_MIPS_HI16 against `_gp' can not be used when making a shared object; recompile with -fPIC
This is caused by linker bug and/or non-PIC code in crt1.o.
FAIL: glibcs-powerpc-linux-gnu build
FAIL: glibcs-powerpc-linux-gnu-soft build
FAIL: glibcs-powerpc-linux-gnuspe build
FAIL: glibcs-powerpc-linux-gnuspe-e500v1 build
elf/sln is failed to link due to:
ld: read-only segment has dynamic relocations.
This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
https://sourceware.org/bugzilla/show_bug.cgi?id=22264
FAIL: glibcs-powerpc-linux-gnu-power4 build
elf/sln is failed to link due to:
findlocale.c:96:(.text+0x22c): @local call to ifunc memchr
This is caused by linker bug and/or non-PIC code in PIE libc.a.
FAIL: glibcs-s390-linux-gnu build
elf/sln is failed to link due to:
collect2: fatal error: ld terminated with signal 11 [Segmentation fault], core dumped
assertion fail bfd/elflink.c:14242
This is caused by linker bug and/or non-PIC code in PIE libc.a.
FAIL: glibcs-sh3eb-linux-gnu build
FAIL: glibcs-sh3-linux-gnu build
FAIL: glibcs-sh4eb-linux-gnu build
FAIL: glibcs-sh4eb-linux-gnu-soft build
FAIL: glibcs-sh4-linux-gnu build
FAIL: glibcs-sh4-linux-gnu-soft build
elf/sln is failed to link due to:
ld: read-only segment has dynamic relocations.
This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
https://sourceware.org/bugzilla/show_bug.cgi?id=22263
Also TLS code sequence in SH assembly syscalls in glibc doesn't match TLS
code sequence expected by ld:
https://sourceware.org/bugzilla/show_bug.cgi?id=22270
FAIL: glibcs-sparc64-linux-gnu build
FAIL: glibcs-sparcv9-linux-gnu build
FAIL: glibcs-tilegxbe-linux-gnu build
FAIL: glibcs-tilegxbe-linux-gnu-32 build
FAIL: glibcs-tilegx-linux-gnu build
FAIL: glibcs-tilegx-linux-gnu-32 build
FAIL: glibcs-tilepro-linux-gnu build
elf/sln is failed to link due to:
ld: read-only segment has dynamic relocations.
This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
https://sourceware.org/bugzilla/show_bug.cgi?id=22263
[BZ #19574]
* INSTALL: Regenerated.
* Makeconfig (static-start-installed-name): Add the `r' prefix
for --enable-static-pie.
(pic-default): Updated for --enable-static-pie.
(pie-default): New for --enable-static-pie.
(default-pie-ldflag): Likewise.
(+link-static-before-libc): Use the first of $(DEFAULT-LDFLAGS-$(@F))
and $(default-pie-ldflag).
(+prectorT): Updated for --enable-static-pie.
(+postctorT): Likewise.
(CFLAGS-.o): Add $(pie-default).
(CFLAGS-.op): Likewise.
* NEWS: Mention --enable-static-pie.
* config.h.in (ENABLE_STATIC_PIE): New.
* configure.ac (--enable-static-pie): New configure option.
(have-no-dynamic-linker): New LIBC_CONFIG_VAR.
(have-static-pie): Likewise.
Enable static PIE if linker supports --no-dynamic-linker.
(ENABLE_STATIC_PIE): New AC_DEFINE.
(enable-static-pie): New LIBC_CONFIG_VAR.
* configure: Regenerated.
* csu/Makefile (omit-deps): Add r$(start-installed-name) for
--enable-static-pie.
(extra-objs): Likewise.
(install-lib): Likewise.
(extra-objs): Add static-reloc.o and static-reloc.os
($(objpfx)$(start-installed-name)): Also depend on
$(objpfx)static-reloc.o.
($(objpfx)r$(start-installed-name)): New.
($(objpfx)g$(start-installed-name)): Also depend on
$(objpfx)static-reloc.os.
* csu/libc-start.c (LIBC_START_MAIN): Call _dl_relocate_static_pie
in libc.a.
* csu/libc-tls.c (__libc_setup_tls): Add main_map->l_addr to
initimage.
* csu/static-reloc.c: New file.
* elf/Makefile (routines): Add dl-reloc-static-pie.
(elide-routines.os): Likewise.
* elf/dl-reloc-static-pie.c: New file.
* elf/dl-support.c (_dl_get_dl_main_map): New function.
* elf/dynamic-link.h (ELF_DURING_STARTUP): Also check
STATIC_PIE_BOOTSTRAP.
* elf/get-dynamic-info.h (elf_get_dynamic_info): Likewise.
* gmon/Makefile (tests): Add tst-gmon-static-pie.
(tests-static): Likewise.
(CFLAGS-tst-gmon-static-pie.c): New.
(CRT-tst-gmon-static-pie): Likewise.
(tst-gmon-static-pie-ENV): Likewise.
(tests-special): Likewise.
($(objpfx)tst-gmon-static-pie.out): Likewise.
(clean-tst-gmon-static-pie-data): Likewise.
($(objpfx)tst-gmon-static-pie-gprof.out): Likewise.
* gmon/tst-gmon-static-pie.c: New file.
* manual/install.texi: Document --enable-static-pie.
* sysdeps/generic/ldsodefs.h (_dl_relocate_static_pie): New.
(_dl_get_dl_main_map): Likewise.
* sysdeps/i386/configure.ac: Check if linker supports static PIE.
* sysdeps/x86_64/configure.ac: Likewise.
* sysdeps/i386/configure: Regenerated.
* sysdeps/x86_64/configure: Likewise.
---
INSTALL | 7 ++++
Makeconfig | 34 ++++++++++++++++++--
NEWS | 5 +++
config.h.in | 3 ++
configure | 78 +++++++++++++++++++++++++++++++++++++++++++++
configure.ac | 29 +++++++++++++++++
csu/Makefile | 17 ++++++++--
csu/libc-start.c | 2 ++
csu/libc-tls.c | 6 ++--
csu/static-reloc.c | 26 +++++++++++++++
elf/Makefile | 5 +--
elf/dl-reloc-static-pie.c | 52 ++++++++++++++++++++++++++++++
elf/dl-support.c | 11 +++++++
elf/dynamic-link.h | 2 +-
elf/get-dynamic-info.h | 6 ++--
gmon/Makefile | 23 +++++++++++++
gmon/tst-gmon-static-pie.c | 1 +
manual/install.texi | 7 ++++
sysdeps/generic/ldsodefs.h | 11 +++++++
sysdeps/i386/configure | 33 +++++++++++++++++++
sysdeps/i386/configure.ac | 23 +++++++++++++
sysdeps/x86_64/configure | 33 +++++++++++++++++++
sysdeps/x86_64/configure.ac | 25 +++++++++++++++
23 files changed, 425 insertions(+), 14 deletions(-)
create mode 100644 csu/static-reloc.c
create mode 100644 elf/dl-reloc-static-pie.c
create mode 100644 gmon/tst-gmon-static-pie.c
@@ -90,6 +90,13 @@ will be used, and CFLAGS sets optimization options for the compiler.
systems support shared libraries; you need ELF support and
(currently) the GNU linker.
+'--enable-static-pie'
+ Build static executables, including tests, as position independent
+ executable (static PIE) which is similar to static executable, but
+ can be loaded at any address without help from a dynamic linker.
+ The resulting libc.a can be used with the GCC option, -static-pie,
+ which is available with GCC 8 or above, to create static PIE.
+
'--disable-profile'
Don't build libraries with profiling information. You may want to
use this option if you don't plan to do profiling.
@@ -352,6 +352,12 @@ ifndef static-start-installed-name
static-start-installed-name = $(start-installed-name)
endif
+ifeq (yes,$(enable-static-pie))
+# Link with rcrt1.o, instead of crt1.o, to call _dl_relocate_static_pie
+# to relocate static PIE.
+static-start-installed-name := r$(static-start-installed-name)
+endif
+
ifeq (yesyes,$(build-shared)$(have-z-combreloc))
combreloc-LDFLAGS = -Wl,-z,combreloc
LDFLAGS.so += $(combreloc-LDFLAGS)
@@ -371,6 +377,20 @@ LDFLAGS.so += $(hashstyle-LDFLAGS)
LDFLAGS-rtld += $(hashstyle-LDFLAGS)
endif
+ifeq (yes,$(enable-static-pie))
+pic-default = -DPIC
+# Compile libc.a and libc_p.a with -fPIE/-fpie for static PIE.
+pie-default = $(pie-ccflag)
+ifeq (yes,$(have-static-pie))
+default-pie-ldflag = -static-pie
+else
+# Static PIE can't have dynamic relocations in read-only segments since
+# static PIE is mapped into memory by kernel. --eh-frame-hdr is needed
+# for PIE to support exception.
+default-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
+endif
+endif
+
# If lazy relocations are disabled, add the -z now flag. Use
# LDFLAGS-lib.so instead of LDFLAGS.so, to avoid adding the flag to
# test modules.
@@ -420,7 +440,7 @@ endif
# Command for statically linking programs with the C library.
ifndef +link-static
+link-static-before-libc = $(CC) -nostdlib -nostartfiles -static -o $@ \
- $(DEFAULT-LDFLAGS-$(@F)) \
+ $(firstword $(DEFAULT-LDFLAGS-$(@F)) $(default-pie-ldflag)) \
$(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \
$(firstword $(CRT-$(@F)) $(csu-objpfx)$(static-start-installed-name)) \
$(+preinit) $(+prectorT) \
@@ -637,8 +657,14 @@ endif
+prectorS = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtbeginS.o`
+postctorS = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtendS.o`
# Variants of the two previous definitions for statically linking programs.
+ifeq (yes,$(enable-static-pie))
+# Static PIE must use PIE variants.
++prectorT = $(+prectorS)
++postctorT = $(+postctorS)
+else
+prectorT = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtbeginT.o`
+postctorT = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtend.o`
+endif
csu-objpfx = $(common-objpfx)csu/
elf-objpfx = $(common-objpfx)elf/
@@ -959,7 +985,8 @@ libtypes = $(foreach o,$(object-suffixes-for-libc),$(libtype$o))
all-object-suffixes := .o .os .oS
object-suffixes :=
CPPFLAGS-.o = $(pic-default)
-CFLAGS-.o = $(filter %frame-pointer,$(+cflags))
+# libc.a must be compiled with -fPIE/-fpie for static PIE.
+CFLAGS-.o = $(filter %frame-pointer,$(+cflags)) $(pie-default)
libtype.o := lib%.a
object-suffixes += .o
ifeq (yes,$(build-shared))
@@ -984,7 +1011,8 @@ ifeq (yes,$(build-profile))
all-object-suffixes += .op
object-suffixes += .op
CPPFLAGS-.op = -DPROF $(pic-default)
-CFLAGS-.op = -pg
+# libc_p.a must be compiled with -fPIE/-fpie for static PIE.
+CFLAGS-.op = -pg $(pie-default)
libtype.op = lib%_p.a
endif
@@ -9,6 +9,11 @@ Version 2.27
Major new features:
+* Add --enable-static-pie configure option to build static PIE. The
+ resulting libc.a can be used with the GCC option, -static-pie, which
+ is available with GCC 8 or above, to create static position independent
+ executable (static PIE).
+
* Optimized x86-64 asin, atan2, exp, expf, log, pow, atan, sin and tan
with FMA, contributed by Arjan van de Ven and H.J. Lu from Intel.
@@ -244,6 +244,9 @@
/* Build glibc with tunables support. */
#define HAVE_TUNABLES 0
+/* Define if static PIE is enabled. */
+#define ENABLE_STATIC_PIE 0
+
/* Some compiler options may now allow to use ebp in __asm__ (used mainly
in i386 6 argument syscall issue). */
#define CAN_USE_REGISTER_ASM_EBP 0
@@ -765,6 +765,7 @@ with_default_link
enable_sanity_checks
enable_shared
enable_profile
+enable_static_pie
enable_timezone_tools
enable_hardcoded_path_in_tests
enable_stackguard_randomization
@@ -1420,6 +1421,7 @@ Optional Features:
in special situations) [default=yes]
--enable-shared build shared library [default=yes if GNU ld]
--enable-profile build profiled library [default=no]
+ --enable-static-pie build static executables as PIE [default=no]
--disable-timezone-tools
do not install timezone tools [default=install]
--enable-hardcoded-path-in-tests
@@ -3365,6 +3367,13 @@ else
profile=no
fi
+# Check whether --enable-static-pie was given.
+if test "${enable_static_pie+set}" = set; then :
+ enableval=$enable_static_pie; static_pie=$enableval
+else
+ static_pie=no
+fi
+
# Check whether --enable-timezone-tools was given.
if test "${enable_timezone_tools+set}" = set; then :
enableval=$enable_timezone_tools; enable_timezone_tools=$enableval
@@ -5805,6 +5814,62 @@ fi
$as_echo "$libc_linker_feature" >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker that supports --no-dynamic-linker" >&5
+$as_echo_n "checking for linker that supports --no-dynamic-linker... " >&6; }
+libc_linker_feature=no
+if test x"$gnu_ld" = x"yes"; then
+ libc_linker_check=`$LD -v --help 2>/dev/null | grep "\--no-dynamic-linker"`
+ if test -n "$libc_linker_check"; then
+ cat > conftest.c <<EOF
+int _start (void) { return 42; }
+EOF
+ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
+ -Wl,--no-dynamic-linker -nostdlib -nostartfiles
+ -fPIC -shared -o conftest.so conftest.c
+ 1>&5'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }
+ then
+ libc_linker_feature=yes
+ fi
+ rm -f conftest*
+ fi
+fi
+if test $libc_linker_feature = yes; then
+ libc_cv_no_dynamic_linker=yes
+else
+ libc_cv_no_dynamic_linker=no
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5
+$as_echo "$libc_linker_feature" >&6; }
+config_vars="$config_vars
+have-no-dynamic-linker = $libc_cv_no_dynamic_linker"
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for -static-pie" >&5
+$as_echo_n "checking for -static-pie... " >&6; }
+if ${libc_cv_static_pie+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ if { ac_try='${CC-cc} -static-pie -xc /dev/null -S -o /dev/null'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }; then :
+ libc_cv_static_pie=yes
+else
+ libc_cv_static_pie=no
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_static_pie" >&5
+$as_echo "$libc_cv_static_pie" >&6; }
+config_vars="$config_vars
+have-static-pie = $libc_cv_static_pie"
+
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for -fpie" >&5
$as_echo_n "checking for -fpie... " >&6; }
if ${libc_cv_fpie+:} false; then :
@@ -6704,6 +6769,19 @@ $as_echo "$libc_cv_pie_default" >&6; }
libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory`
+if test "$static_pie" = yes; then
+ # The linker must support --no-dynamic-linker.
+ if test "$libc_cv_no_dynamic_linker" != yes; then
+ as_fn_error $? "linker support for --no-dynamic-linker needed" "$LINENO" 5
+ fi
+ # Default to PIE.
+ libc_cv_pie_default=yes
+ $as_echo "#define ENABLE_STATIC_PIE 1" >>confdefs.h
+
+fi
+config_vars="$config_vars
+enable-static-pie = $static_pie"
+
@@ -176,6 +176,11 @@ AC_ARG_ENABLE([profile],
[build profiled library @<:@default=no@:>@]),
[profile=$enableval],
[profile=no])
+AC_ARG_ENABLE([static-pie],
+ AC_HELP_STRING([--enable-static-pie],
+ [build static executables as PIE @<:@default=no@:>@]),
+ [static_pie=$enableval],
+ [static_pie=no])
AC_ARG_ENABLE([timezone-tools],
AC_HELP_STRING([--disable-timezone-tools],
[do not install timezone tools @<:@default=install@:>@]),
@@ -1281,6 +1286,19 @@ LIBC_LINKER_FEATURE([-z execstack], [-Wl,-z,execstack],
[libc_cv_z_execstack=yes], [libc_cv_z_execstack=no])
AC_SUBST(libc_cv_z_execstack)
+LIBC_LINKER_FEATURE([--no-dynamic-linker],
+ [-Wl,--no-dynamic-linker],
+ [libc_cv_no_dynamic_linker=yes],
+ [libc_cv_no_dynamic_linker=no])
+LIBC_CONFIG_VAR([have-no-dynamic-linker], [$libc_cv_no_dynamic_linker])
+
+AC_CACHE_CHECK(for -static-pie, libc_cv_static_pie, [dnl
+LIBC_TRY_CC_OPTION([-static-pie],
+ [libc_cv_static_pie=yes],
+ [libc_cv_static_pie=no])
+])
+LIBC_CONFIG_VAR([have-static-pie], [$libc_cv_static_pie])
+
AC_CACHE_CHECK(for -fpie, libc_cv_fpie, [dnl
LIBC_TRY_CC_OPTION([-fpie], [libc_cv_fpie=yes], [libc_cv_fpie=no])
])
@@ -1788,6 +1806,17 @@ AC_SUBST(libc_cv_pie_default)
libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory`
AC_SUBST(libc_cv_multidir)
+if test "$static_pie" = yes; then
+ # The linker must support --no-dynamic-linker.
+ if test "$libc_cv_no_dynamic_linker" != yes; then
+ AC_MSG_ERROR([linker support for --no-dynamic-linker needed])
+ fi
+ # Default to PIE.
+ libc_cv_pie_default=yes
+ AC_DEFINE(ENABLE_STATIC_PIE)
+fi
+LIBC_CONFIG_VAR([enable-static-pie], [$static_pie])
+
AC_SUBST(profile)
AC_SUBST(static_nss)
@@ -37,7 +37,8 @@ extra-objs = start.o \
S$(start-installed-name)
omit-deps = $(patsubst %.o,%,$(start-installed-name) g$(start-installed-name) \
b$(start-installed-name) $(csu-dummies) \
- S$(start-installed-name))
+ S$(start-installed-name) \
+ r$(start-installed-name))
install-lib = $(start-installed-name) g$(start-installed-name) $(csu-dummies)
# No tests are allowed in the csu/ subdirectory because the startup
@@ -55,6 +56,10 @@ extra-objs += gmon-start.o
endif
install-lib += S$(start-installed-name)
generated += start.os
+ifeq (yes,$(enable-static-pie))
+extra-objs += r$(start-installed-name)
+install-lib += r$(start-installed-name)
+endif
else
extra-objs += gmon-start.o
endif
@@ -82,7 +87,10 @@ multilib-extra-objs = $(addprefix $(multidir)/, $(install-lib))
extra-objs += $(multilib-extra-objs)
endif
-extra-objs += abi-note.o init.o
+extra-objs += abi-note.o init.o static-reloc.o
+ifeq (yes,$(build-shared))
+extra-objs += static-reloc.os
+endif
asm-CPPFLAGS += -I$(objpfx).
# Enable unwinding so backtrace unwinds to __libc_start_main
@@ -101,6 +109,9 @@ ifndef start-installed-name-rule
# We link the ELF startfile along with a SHT_NOTE section indicating
# the kernel ABI the binaries linked with this library will require.
$(objpfx)$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
+ $(objpfx)init.o $(objpfx)static-reloc.o
+ $(link-relocatable)
+$(objpfx)r$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
$(objpfx)init.o
$(link-relocatable)
$(objpfx)S$(start-installed-name): $(objpfx)start.os $(objpfx)abi-note.o \
@@ -113,7 +124,7 @@ endif
# to turn on profiling code at startup.
ifeq (yes,$(build-shared))
$(objpfx)g$(start-installed-name): \
- $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os
+ $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os $(objpfx)static-reloc.os
$(link-relocatable)
ifneq ($(start-installed-name),$(static-start-installed-name))
$(objpfx)g$(static-start-installed-name): \
@@ -141,6 +141,8 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
__libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
#ifndef SHARED
+ _dl_relocate_static_pie ();
+
char **ev = &argv[argc + 1];
__environ = ev;
@@ -114,6 +114,8 @@ __libc_setup_tls (void)
size_t tcb_offset;
const ElfW(Phdr) *phdr;
+ struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
+
/* Look through the TLS segment if there is any. */
if (_dl_phdr != NULL)
for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)
@@ -122,7 +124,7 @@ __libc_setup_tls (void)
/* Remember the values we need. */
memsz = phdr->p_memsz;
filesz = phdr->p_filesz;
- initimage = (void *) phdr->p_vaddr;
+ initimage = (void *) phdr->p_vaddr + main_map->l_addr;
align = phdr->p_align;
if (phdr->p_align > max_align)
max_align = phdr->p_align;
@@ -163,8 +165,6 @@ __libc_setup_tls (void)
_dl_static_dtv[0].counter = (sizeof (_dl_static_dtv) / sizeof (_dl_static_dtv[0])) - 2;
// _dl_static_dtv[1].counter = 0; would be needed if not already done
- struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
-
/* Initialize the TLS block. */
#if TLS_TCB_AT_TP
_dl_static_dtv[2].pointer.val = ((char *) tlsblock + tcb_offset
new file mode 100644
@@ -0,0 +1,26 @@
+/* Special startup support for non-PIE static executables.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#if ENABLE_STATIC_PIE
+#include <ldsodefs.h>
+
+void
+_dl_relocate_static_pie (void)
+{
+}
+#endif
@@ -24,7 +24,8 @@ include ../Makeconfig
headers = elf.h bits/elfclass.h link.h bits/link.h
routines = $(all-dl-routines) dl-support dl-iteratephdr \
dl-addr dl-addr-obj enbl-secure dl-profstub \
- dl-origin dl-libc dl-sym dl-sysdep dl-error
+ dl-origin dl-libc dl-sym dl-sysdep dl-error \
+ dl-reloc-static-pie
# The core dynamic linking functions are in libc for the static and
# profiled libraries.
@@ -52,7 +53,7 @@ endif
all-dl-routines = $(dl-routines) $(sysdep-dl-routines)
# But they are absent from the shared libc, because that code is in ld.so.
elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \
- dl-sysdep dl-exception
+ dl-sysdep dl-exception dl-reloc-static-pie
shared-only-routines += dl-caller
# ld.so uses those routines, plus some special stuff for being the program
new file mode 100644
@@ -0,0 +1,52 @@
+/* Support for relocating static PIE.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#if ENABLE_STATIC_PIE
+#include <unistd.h>
+#include <ldsodefs.h>
+#include "dynamic-link.h"
+
+/* Relocate static executable with PIE. */
+
+void
+_dl_relocate_static_pie (void)
+{
+ struct link_map *main_map = _dl_get_dl_main_map ();
+
+# define STATIC_PIE_BOOTSTRAP
+# define BOOTSTRAP_MAP (main_map)
+# define RESOLVE_MAP(sym, version, flags) BOOTSTRAP_MAP
+# include "dynamic-link.h"
+
+ /* Figure out the run-time load address of static PIE. */
+ main_map->l_addr = elf_machine_load_address ();
+
+ /* Read our own dynamic section and fill in the info array. */
+ main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ());
+ elf_get_dynamic_info (main_map, NULL);
+
+# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
+ ELF_MACHINE_BEFORE_RTLD_RELOC (main_map->l_info);
+# endif
+
+ /* Relocate ourselves so we can do normal function calls and
+ data access using the global offset table. */
+ ELF_DYNAMIC_RELOCATE (main_map, 0, 0, 0);
+ main_map->l_relocated = 1;
+}
+#endif
@@ -385,3 +385,14 @@ _dl_non_dynamic_init (void)
#ifdef DL_SYSINFO_IMPLEMENTATION
DL_SYSINFO_IMPLEMENTATION
#endif
+
+#if ENABLE_STATIC_PIE
+/* Since relocation to hidden _dl_main_map causes relocation overflow on
+ aarch64, a function is used to get the address of _dl_main_map. */
+
+struct link_map *
+_dl_get_dl_main_map (void)
+{
+ return &_dl_main_map;
+}
+#endif
@@ -94,7 +94,7 @@ elf_machine_lazy_rel (struct link_map *map,
#ifdef RESOLVE_MAP
-# ifdef RTLD_BOOTSTRAP
+# if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP
# define ELF_DURING_STARTUP (1)
# else
# define ELF_DURING_STARTUP (0)
@@ -38,7 +38,7 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
typedef Elf64_Xword d_tag_utype;
#endif
-#ifndef RTLD_BOOTSTRAP
+#if !defined RTLD_BOOTSTRAP && !defined STATIC_PIE_BOOTSTRAP
if (dyn == NULL)
return;
#endif
@@ -139,9 +139,11 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
/* Only the bind now flags are allowed. */
assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
|| (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
+ /* Flags must not be set for ld.so. */
assert (info[DT_FLAGS] == NULL
|| (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
- /* Flags must not be set for ld.so. */
+#endif
+#if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP
assert (info[DT_RUNPATH] == NULL);
assert (info[DT_RPATH] == NULL);
#else
@@ -39,6 +39,10 @@ tests-static += tst-gmon-static
ifeq (yesyes,$(have-fpie)$(build-shared))
tests += tst-gmon-pie
tests-pie += tst-gmon-pie
+ifeq (yes,$(enable-static-pie))
+tests += tst-gmon-static-pie
+tests-static += tst-gmon-static-pie
+endif
endif
# The mcount code won't work without a frame pointer.
@@ -67,6 +71,15 @@ ifeq ($(run-built-tests),yes)
tests-special += $(objpfx)tst-gmon-pie-gprof.out
endif
+ifeq (yes,$(enable-static-pie))
+CFLAGS-tst-gmon-static-pie.c := $(PIE-ccflag) -fno-omit-frame-pointer -pg
+CRT-tst-gmon-static-pie := $(csu-objpfx)grcrt1.o
+tst-gmon-static-pie-ENV := GMON_OUT_PREFIX=$(objpfx)tst-gmon-static-pie.data
+ifeq ($(run-built-tests),yes)
+tests-special += $(objpfx)tst-gmon-static-pie-gprof.out
+endif
+endif
+
include ../Rules
@@ -111,3 +124,13 @@ clean-tst-gmon-pie-data:
$(objpfx)tst-gmon-pie-gprof.out: tst-gmon-gprof.sh $(objpfx)tst-gmon-pie.out
$(SHELL) $< $(GPROF) $(objpfx)tst-gmon-pie $(objpfx)tst-gmon-pie.data.* > $@; \
$(evaluate-test)
+
+$(objpfx)tst-gmon-static-pie.out: clean-tst-gmon-static-pie-data
+clean-tst-gmon-static-pie-data:
+ rm -f $(objpfx)tst-gmon-static-pie.data.*
+
+$(objpfx)tst-gmon-static-pie-gprof.out: tst-gmon-static-gprof.sh \
+ $(objpfx)tst-gmon-static-pie.out
+ $(SHELL) $< $(GPROF) $(objpfx)tst-gmon-static-pie \
+ $(objpfx)tst-gmon-static-pie.data.* > $@; \
+ $(evaluate-test)
new file mode 100644
@@ -0,0 +1 @@
+#include "tst-gmon.c"
@@ -120,6 +120,13 @@ Don't build shared libraries even if it is possible. Not all systems
support shared libraries; you need ELF support and (currently) the GNU
linker.
+@item --enable-static-pie
+Build static executables, including tests, as position independent
+executable (static PIE) which is similar to static executable, but can
+be loaded at any address without help from a dynamic linker. The
+resulting libc.a can be used with the GCC option, -static-pie, which
+is available with GCC 8 or above, to create static PIE.
+
@item --disable-profile
Don't build libraries with profiling information. You may want to use
this option if you don't plan to do profiling.
@@ -1051,6 +1051,17 @@ extern void _dl_determine_tlsoffset (void) attribute_hidden;
stack protector, among other things). */
void __libc_setup_tls (void);
+# if ENABLE_STATIC_PIE
+/* Relocate static executable with PIE. */
+extern void _dl_relocate_static_pie (void) attribute_hidden;
+
+/* Get a pointer to _dl_main_map. */
+extern struct link_map * _dl_get_dl_main_map (void)
+ __attribute__ ((visibility ("hidden")));
+# else
+# define _dl_relocate_static_pie()
+# endif
+
/* Initialization of libpthread for statically linked applications.
If libpthread is not linked in, this is an empty function. */
void __pthread_initialize_minimal (void) weak_function;
@@ -50,6 +50,39 @@ fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_compiler_builtin_inlined" >&5
$as_echo "$libc_compiler_builtin_inlined" >&6; }
+if test "$static_pie" = yes; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker static PIE support" >&5
+$as_echo_n "checking for linker static PIE support... " >&6; }
+if ${libc_cv_ld_static_pie+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat > conftest.s <<\EOF
+ .text
+ .global _start
+_start:
+ movl _start@GOT(%ebx), %eax
+EOF
+ libc_cv_pie_option="-Wl,-pie"
+ libc_cv_ld_static_pie=no
+ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&5'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }; then
+ if $READELF -r conftest | grep 'There are no relocations in this file.' > /dev/null; then
+ libc_cv_ld_static_pie=yes
+ fi
+ fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ld_static_pie" >&5
+$as_echo "$libc_cv_ld_static_pie" >&6; }
+ if test "$libc_cv_ld_static_pie" != yes; then
+ as_fn_error $? "linker support for static PIE needed" "$LINENO" 5
+ fi
+fi
+
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Intel MPX support" >&5
$as_echo_n "checking for Intel MPX support... " >&6; }
if ${libc_cv_asm_mpx+:} false; then :
@@ -30,6 +30,29 @@ LIBC_COMPILER_BUILTIN_INLINED(
*** Please use host i786, i686, i586, or i486.
*** For example: /source/glibc/configure CFLAGS='-O2 -march=i686' ...])])
+dnl Check if linker can convert "movl main@GOT(%ebx), %eax" to
+dnl "leal main@GOTOFF(%ebx), %eax" for static PIE.
+if test "$static_pie" = yes; then
+ AC_CACHE_CHECK(for linker static PIE support, libc_cv_ld_static_pie, [dnl
+cat > conftest.s <<\EOF
+ .text
+ .global _start
+_start:
+ movl _start@GOT(%ebx), %eax
+EOF
+ libc_cv_pie_option="-Wl,-pie"
+ libc_cv_ld_static_pie=no
+ if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&AS_MESSAGE_LOG_FD); then
+ if $READELF -r conftest | grep 'There are no relocations in this file.' > /dev/null; then
+ libc_cv_ld_static_pie=yes
+ fi
+ fi
+rm -f conftest*])
+ if test "$libc_cv_ld_static_pie" != yes; then
+ AC_MSG_ERROR([linker support for static PIE needed])
+ fi
+fi
+
dnl Check whether asm supports Intel MPX
AC_CACHE_CHECK(for Intel MPX support, libc_cv_asm_mpx, [dnl
cat > conftest.s <<\EOF
@@ -85,6 +85,39 @@ if test x"$build_mathvec" = xnotset; then
build_mathvec=yes
fi
+if test "$static_pie" = yes; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker static PIE support" >&5
+$as_echo_n "checking for linker static PIE support... " >&6; }
+if ${libc_cv_ld_static_pie+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat > conftest.s <<\EOF
+ .text
+ .global _start
+ .weak foo
+_start:
+ leaq foo(%rip), %rax
+EOF
+ libc_cv_pie_option="-Wl,-pie"
+ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&5'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }; then
+ libc_cv_ld_static_pie=yes
+ else
+ libc_cv_ld_static_pie=no
+ fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ld_static_pie" >&5
+$as_echo "$libc_cv_ld_static_pie" >&6; }
+ if test "$libc_cv_ld_static_pie" != yes; then
+ as_fn_error $? "linker support for static PIE needed" "$LINENO" 5
+ fi
+fi
+
$as_echo "#define PI_STATIC_AND_HIDDEN 1" >>confdefs.h
@@ -44,6 +44,31 @@ if test x"$build_mathvec" = xnotset; then
build_mathvec=yes
fi
+dnl Check if linker supports static PIE with the fix for
+dnl
+dnl https://sourceware.org/bugzilla/show_bug.cgi?id=21782
+dnl
+if test "$static_pie" = yes; then
+ AC_CACHE_CHECK(for linker static PIE support, libc_cv_ld_static_pie, [dnl
+cat > conftest.s <<\EOF
+ .text
+ .global _start
+ .weak foo
+_start:
+ leaq foo(%rip), %rax
+EOF
+ libc_cv_pie_option="-Wl,-pie"
+ if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&AS_MESSAGE_LOG_FD); then
+ libc_cv_ld_static_pie=yes
+ else
+ libc_cv_ld_static_pie=no
+ fi
+rm -f conftest*])
+ if test "$libc_cv_ld_static_pie" != yes; then
+ AC_MSG_ERROR([linker support for static PIE needed])
+ fi
+fi
+
dnl It is always possible to access static and hidden symbols in an
dnl position independent way.
AC_DEFINE(PI_STATIC_AND_HIDDEN)
--
2.14.3