[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 12 Oct 2017 11:28:15 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: Thomas Garnier <thgarnie@...gle.com>
Cc: Herbert Xu <herbert@...dor.apana.org.au>,
"David S . Miller" <davem@...emloft.net>,
Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, Peter Zijlstra <peterz@...radead.org>,
Josh Poimboeuf <jpoimboe@...hat.com>, Arnd Bergmann <arnd@...db.de>,
Kees Cook <keescook@...omium.org>, Andrey Ryabinin
<aryabinin@...tuozzo.com>, Matthias Kaehlcke <mka@...omium.org>,
Andy Lutomirski <luto@...nel.org>,
"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
Borislav Petkov <bp@...e.de>, "Rafael J . Wysocki" <rjw@...ysocki.net>,
Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
Juergen Gross <jgross@...e.com>, Chris Wright <chrisw@...s-sol.org>,
Alok Kataria <akataria@...are.com>, Rusty Russell <rusty@...tcorp.com.au>,
Tejun Heo <tj@...nel.org>, Christoph Lameter <cl@...ux.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Paul Gortmaker <paul.gortmaker@...driver.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Alexey Dobriyan <adobriyan@...il.com>,
"Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
Nicolas Pitre <nicolas.pitre@...aro.org>, Borislav Petkov <bp@...en8.de>,
"Luis R . Rodriguez" <mcgrof@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Christopher Li <sparse@...isli.org>, Steven Rostedt <rostedt@...dmis.org>,
Jason Baron <jbaron@...mai.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
Dou Liyang <douly.fnst@...fujitsu.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
Lukas Wunner <lukas@...ner.de>,
Masahiro Yamada <yamada.masahiro@...ionext.com>,
Alexei Starovoitov <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>,
Markus Trippelsdorf <markus@...ppelsdorf.de>,
Paolo Bonzini <pbonzini@...hat.com>, Radim Krčmář
<rkrcmar@...hat.com>, Joerg Roedel <joro@...tes.org>,
Rik van Riel <riel@...hat.com>, David Howells <dhowells@...hat.com>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>, Waiman Long
<longman@...hat.com>, Kyle Huey <me@...ehuey.com>,
Jonathan Corbet <corbet@....net>, Michal Hocko <mhocko@...e.com>,
Peter Foley <pefoley2@...oley.com>, Paul Bolle <pebolle@...cali.nl>,
Jiri Kosina <jkosina@...e.cz>, "H . J . Lu" <hjl.tools@...il.com>,
Rob Landley <rob@...dley.net>, Baoquan He <bhe@...hat.com>,
Jan H . Schönherr <jschoenh@...zon.de>,
Daniel Micay <danielmicay@...il.com>,
the arch/x86 maintainers <x86@...nel.org>,
Linux Crypto Mailing List <linux-crypto@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>, Linux PM list
<linux-pm@...r.kernel.org>, virtualization@...ts.linux-foundation.org,
xen-devel <xen-devel@...ts.xenproject.org>,
linux-arch <linux-arch@...r.kernel.org>,
Sparse Mailing-list <linux-sparse@...r.kernel.org>,
kvm list <kvm@...r.kernel.org>, linux-doc@...r.kernel.org,
Kernel Hardening <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH v1 00/27] x86: PIE support and option to extend KASLR
randomization
On 10/12/2017 10:34 AM, Thomas Garnier wrote:
> On Wed, Oct 11, 2017 at 2:34 PM, Tom Lendacky <thomas.lendacky@....com> wrote:
>> On 10/11/2017 3:30 PM, Thomas Garnier wrote:
>>> Changes:
>>> - patch v1:
>>> - Simplify ftrace implementation.
>>> - Use gcc mstack-protector-guard-reg=%gs with PIE when possible.
>>> - rfc v3:
>>> - Use --emit-relocs instead of -pie to reduce dynamic relocation space on
>>> mapped memory. It also simplifies the relocation process.
>>> - Move the start the module section next to the kernel. Remove the need for
>>> -mcmodel=large on modules. Extends module space from 1 to 2G maximum.
>>> - Support for XEN PVH as 32-bit relocations can be ignored with
>>> --emit-relocs.
>>> - Support for GOT relocations previously done automatically with -pie.
>>> - Remove need for dynamic PLT in modules.
>>> - Support dymamic GOT for modules.
>>> - rfc v2:
>>> - Add support for global stack cookie while compiler default to fs without
>>> mcmodel=kernel
>>> - Change patch 7 to correctly jump out of the identity mapping on kexec load
>>> preserve.
>>>
>>> These patches make the changes necessary to build the kernel as Position
>>> Independent Executable (PIE) on x86_64. A PIE kernel can be relocated below
>>> the top 2G of the virtual address space. It allows to optionally extend the
>>> KASLR randomization range from 1G to 3G.
>>
>> Hi Thomas,
>>
>> I've applied your patches so that I can verify that SME works with PIE.
>> Unfortunately, I'm running into build warnings and errors when I enable
>> PIE.
>>
>> With CONFIG_STACK_VALIDATION=y I receive lots of messages like this:
>>
>> drivers/scsi/libfc/fc_exch.o: warning: objtool: fc_destroy_exch_mgr()+0x0: call without frame pointer save/setup
>>
>> Disabling CONFIG_STACK_VALIDATION suppresses those.
>
> I ran into that, I plan to fix it in the next iteration.
>
>>
>> But near the end of the build, I receive errors like this:
>>
>> arch/x86/kernel/setup.o: In function `dump_kernel_offset':
>> .../arch/x86/kernel/setup.c:801:(.text+0x32): relocation truncated to fit: R_X86_64_32S against symbol `_text' defined in .text section in .tmp_vmlinux1
>> .
>> . about 10 more of the above type messages
>> .
>> make: *** [vmlinux] Error 1
>> Error building kernel, exiting
>>
>> Are there any config options that should or should not be enabled when
>> building with PIE enabled? Is there a compiler requirement for PIE (I'm
>> using gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.5))?
>
> I never ran into these ones and I tested compilers older and newer.
> What was your exact configuration?
I'll send you the config in a separate email.
Thanks,
Tom
>
>>
>> Thanks,
>> Tom
>>
>>>
>>> Thanks a lot to Ard Biesheuvel & Kees Cook on their feedback on compiler
>>> changes, PIE support and KASLR in general. Thanks to Roland McGrath on his
>>> feedback for using -pie versus --emit-relocs and details on compiler code
>>> generation.
>>>
>>> The patches:
>>> - 1-3, 5-1#, 17-18: Change in assembly code to be PIE compliant.
>>> - 4: Add a new _ASM_GET_PTR macro to fetch a symbol address generically.
>>> - 14: Adapt percpu design to work correctly when PIE is enabled.
>>> - 15: Provide an option to default visibility to hidden except for key symbols.
>>> It removes errors between compilation units.
>>> - 16: Adapt relocation tool to handle PIE binary correctly.
>>> - 19: Add support for global cookie.
>>> - 20: Support ftrace with PIE (used on Ubuntu config).
>>> - 21: Fix incorrect address marker on dump_pagetables.
>>> - 22: Add option to move the module section just after the kernel.
>>> - 23: Adapt module loading to support PIE with dynamic GOT.
>>> - 24: Make the GOT read-only.
>>> - 25: Add the CONFIG_X86_PIE option (off by default).
>>> - 26: Adapt relocation tool to generate a 64-bit relocation table.
>>> - 27: Add the CONFIG_RANDOMIZE_BASE_LARGE option to increase relocation range
>>> from 1G to 3G (off by default).
>>>
>>> Performance/Size impact:
>>>
>>> Size of vmlinux (Default configuration):
>>> File size:
>>> - PIE disabled: +0.000031%
>>> - PIE enabled: -3.210% (less relocations)
>>> .text section:
>>> - PIE disabled: +0.000644%
>>> - PIE enabled: +0.837%
>>>
>>> Size of vmlinux (Ubuntu configuration):
>>> File size:
>>> - PIE disabled: -0.201%
>>> - PIE enabled: -0.082%
>>> .text section:
>>> - PIE disabled: same
>>> - PIE enabled: +1.319%
>>>
>>> Size of vmlinux (Default configuration + ORC):
>>> File size:
>>> - PIE enabled: -3.167%
>>> .text section:
>>> - PIE enabled: +0.814%
>>>
>>> Size of vmlinux (Ubuntu configuration + ORC):
>>> File size:
>>> - PIE enabled: -3.167%
>>> .text section:
>>> - PIE enabled: +1.26%
>>>
>>> The size increase is mainly due to not having access to the 32-bit signed
>>> relocation that can be used with mcmodel=kernel. A small part is due to reduced
>>> optimization for PIE code. This bug [1] was opened with gcc to provide a better
>>> code generation for kernel PIE.
>>>
>>> Hackbench (50% and 1600% on thread/process for pipe/sockets):
>>> - PIE disabled: no significant change (avg +0.1% on latest test).
>>> - PIE enabled: between -0.50% to +0.86% in average (default and Ubuntu config).
>>>
>>> slab_test (average of 10 runs):
>>> - PIE disabled: no significant change (-2% on latest run, likely noise).
>>> - PIE enabled: between -1% and +0.8% on latest runs.
>>>
>>> Kernbench (average of 10 Half and Optimal runs):
>>> Elapsed Time:
>>> - PIE disabled: no significant change (avg -0.239%)
>>> - PIE enabled: average +0.07%
>>> System Time:
>>> - PIE disabled: no significant change (avg -0.277%)
>>> - PIE enabled: average +0.7%
>>>
>>> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82303
>>>
>>> diffstat:
>>> Documentation/x86/x86_64/mm.txt | 3
>>> arch/x86/Kconfig | 43 ++++++
>>> arch/x86/Makefile | 40 +++++
>>> arch/x86/boot/boot.h | 2
>>> arch/x86/boot/compressed/Makefile | 5
>>> arch/x86/boot/compressed/misc.c | 10 +
>>> arch/x86/crypto/aes-x86_64-asm_64.S | 45 ++++--
>>> arch/x86/crypto/aesni-intel_asm.S | 14 +-
>>> arch/x86/crypto/aesni-intel_avx-x86_64.S | 6
>>> arch/x86/crypto/camellia-aesni-avx-asm_64.S | 42 +++---
>>> arch/x86/crypto/camellia-aesni-avx2-asm_64.S | 44 +++---
>>> arch/x86/crypto/camellia-x86_64-asm_64.S | 8 -
>>> arch/x86/crypto/cast5-avx-x86_64-asm_64.S | 50 ++++---
>>> arch/x86/crypto/cast6-avx-x86_64-asm_64.S | 44 +++---
>>> arch/x86/crypto/des3_ede-asm_64.S | 96 +++++++++-----
>>> arch/x86/crypto/ghash-clmulni-intel_asm.S | 4
>>> arch/x86/crypto/glue_helper-asm-avx.S | 4
>>> arch/x86/crypto/glue_helper-asm-avx2.S | 6
>>> arch/x86/entry/entry_32.S | 3
>>> arch/x86/entry/entry_64.S | 29 ++--
>>> arch/x86/include/asm/asm.h | 13 +
>>> arch/x86/include/asm/bug.h | 2
>>> arch/x86/include/asm/ftrace.h | 6
>>> arch/x86/include/asm/jump_label.h | 8 -
>>> arch/x86/include/asm/kvm_host.h | 6
>>> arch/x86/include/asm/module.h | 11 +
>>> arch/x86/include/asm/page_64_types.h | 9 +
>>> arch/x86/include/asm/paravirt_types.h | 12 +
>>> arch/x86/include/asm/percpu.h | 25 ++-
>>> arch/x86/include/asm/pgtable_64_types.h | 6
>>> arch/x86/include/asm/pm-trace.h | 2
>>> arch/x86/include/asm/processor.h | 12 +
>>> arch/x86/include/asm/sections.h | 8 +
>>> arch/x86/include/asm/setup.h | 2
>>> arch/x86/include/asm/stackprotector.h | 19 ++
>>> arch/x86/kernel/acpi/wakeup_64.S | 31 ++--
>>> arch/x86/kernel/asm-offsets.c | 3
>>> arch/x86/kernel/asm-offsets_32.c | 3
>>> arch/x86/kernel/asm-offsets_64.c | 3
>>> arch/x86/kernel/cpu/common.c | 7 -
>>> arch/x86/kernel/cpu/microcode/core.c | 4
>>> arch/x86/kernel/ftrace.c | 42 +++++-
>>> arch/x86/kernel/head64.c | 32 +++-
>>> arch/x86/kernel/head_32.S | 3
>>> arch/x86/kernel/head_64.S | 41 +++++-
>>> arch/x86/kernel/kvm.c | 6
>>> arch/x86/kernel/module.c | 182 ++++++++++++++++++++++++++-
>>> arch/x86/kernel/module.lds | 3
>>> arch/x86/kernel/process.c | 5
>>> arch/x86/kernel/relocate_kernel_64.S | 8 -
>>> arch/x86/kernel/setup_percpu.c | 2
>>> arch/x86/kernel/vmlinux.lds.S | 13 +
>>> arch/x86/kvm/svm.c | 4
>>> arch/x86/lib/cmpxchg16b_emu.S | 8 -
>>> arch/x86/mm/dump_pagetables.c | 11 +
>>> arch/x86/power/hibernate_asm_64.S | 4
>>> arch/x86/tools/relocs.c | 170 +++++++++++++++++++++++--
>>> arch/x86/tools/relocs.h | 4
>>> arch/x86/tools/relocs_common.c | 15 +-
>>> arch/x86/xen/xen-asm.S | 12 -
>>> arch/x86/xen/xen-head.S | 9 -
>>> arch/x86/xen/xen-pvh.S | 13 +
>>> drivers/base/firmware_class.c | 4
>>> include/asm-generic/sections.h | 6
>>> include/asm-generic/vmlinux.lds.h | 12 +
>>> include/linux/compiler.h | 8 +
>>> init/Kconfig | 9 +
>>> kernel/kallsyms.c | 16 +-
>>> kernel/trace/trace.h | 4
>>> lib/dynamic_debug.c | 4
>>> 70 files changed, 1032 insertions(+), 308 deletions(-)
>>>
>
>
>
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
