From: Joe Lawrence <joe.lawrence@redhat.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Alexander Lobakin" <alexandr.lobakin@intel.com>,
"Fāng-ruì Sòng" <maskray@google.com>,
linux-hardening@vger.kernel.org, x86@kernel.org,
"Borislav Petkov" <bp@alien8.de>,
"Jesse Brandeburg" <jesse.brandeburg@intel.com>,
"Kristen Carlson Accardi" <kristen@linux.intel.com>,
"Kees Cook" <keescook@chromium.org>,
"Miklos Szeredi" <miklos@szeredi.hu>,
"Ard Biesheuvel" <ardb@kernel.org>,
"Tony Luck" <tony.luck@intel.com>,
"Bruce Schlobohm" <bruce.schlobohm@intel.com>,
"Jessica Yu" <jeyu@kernel.org>,
"kernel test robot" <lkp@intel.com>,
"Miroslav Benes" <mbenes@suse.cz>,
"Evgenii Shatokhin" <eshatokhin@virtuozzo.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Masahiro Yamada" <masahiroy@kernel.org>,
"Michal Marek" <michal.lkml@markovi.net>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Herbert Xu" <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Will Deacon" <will@kernel.org>, "Ingo Molnar" <mingo@redhat.com>,
"Christoph Hellwig" <hch@lst.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Nathan Chancellor" <nathan@kernel.org>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Marios Pomonis" <pomonis@google.com>,
"Sami Tolvanen" <samitolvanen@google.com>,
"H.J. Lu" <hjl.tools@gmail.com>,
"Nicolas Pitre" <nico@fluxnic.net>,
linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
linux-arch@vger.kernel.org, live-patching@vger.kernel.org,
llvm@lists.linux.dev
Subject: Re: [PATCH v10 02/15] livepatch: avoid position-based search if `-z unique-symbol` is available
Date: Wed, 16 Feb 2022 15:32:41 -0500 [thread overview]
Message-ID: <Yg1fab6h1rTjVbYO@redhat.com> (raw)
In-Reply-To: <20220214181000.xln2qgyzgswjxwcz@treble>
On Mon, Feb 14, 2022 at 10:10:00AM -0800, Josh Poimboeuf wrote:
> On Mon, Feb 14, 2022 at 01:24:33PM +0100, Alexander Lobakin wrote:
> > > One idea I mentioned before, it may be worth exploring changing the "F"
> > > in FGKASLR to "File" instead of "Function". In other words, only
> > > shuffle at an object-file granularity. Then, even with duplicates, the
> > > <file+function> symbol pair doesn't change in the symbol table. And as
> > > a bonus, it should help FGKASLR i-cache performance, significantly.
> >
> > Yeah, I keep that in mind. However, this wouldn't solve the
> > duplicate static function names problem, right?
> > Let's say you have a static function f() in file1 and f() in file2,
> > then the layout each boot can be
> >
> > .text.file1 or .text.file2
> > f() f()
> > .text.file2 .text.file1
> > f() f()
> >
> > and position-based search won't work anyway, right?
>
> Right, so we'd have to abandon position-based search in favor of
> file+func based search.
>
> It's not perfect because there are still a few file+func duplicates.
> But it might be good enough. We would presumably just refuse to patch a
> duplicate. Or we could remove them (and enforce their continued removal
> with tooling-based warnings).
>
You're talking about duplicate file+func combinations as stored in the
symbol table?
From a recent rhel-9 development kernel:
$ readelf --wide --symbols vmlinux | \
awk '$4=="FILE" { f=$NF } $4=="OBJECT" || $4=="FUNC" { print $4 " " f "::" $NF }' | \
sort | uniq -c | sort -n | awk '$1 != 1'
2 FUNC bus.c::new_id_store
2 FUNC core.c::native_read_msr
2 FUNC core.c::type_show
2 FUNC diag.c::sk_diag_fill.constprop.0
2 FUNC hid-core.c::hid_exit
2 FUNC hid-core.c::hid_init
2 FUNC inode.c::remove_one
2 FUNC iommu.c::__list_del_entry
2 FUNC msr.c::msr_init
2 FUNC msr.c::msr_read
2 FUNC proc.c::c_next
2 FUNC proc.c::c_start
2 FUNC proc.c::c_stop
2 FUNC raw.c::copy_overflow
2 FUNC raw.c::dst_output
2 FUNC route.c::dst_discard
2 FUNC sysfs.c::name_show
2 FUNC udp.c::copy_overflow
2 FUNC udp.c::udp_lib_close
2 FUNC udp.c::udp_lib_hash
2 FUNC udp.c::udplite_getfrag
2 FUNC udplite.c::udp_lib_close
2 FUNC udplite.c::udp_lib_hash
2 FUNC udplite.c::udplite_sk_init
2 OBJECT acpi.c::__func__.0
2 OBJECT amd.c::__already_done.10
2 OBJECT amd.c::__func__.4
2 OBJECT amd.c::__func__.5
2 OBJECT bus.c::driver_attr_new_id
2 OBJECT bus.c::__func__.1
2 OBJECT bus.c::__func__.2
2 OBJECT bus.c::__func__.3
2 OBJECT bus.c::__func__.4
2 OBJECT bus.c::__func__.5
2 OBJECT bus.c::__func__.6
2 OBJECT bus.c::__func__.7
2 OBJECT bus.c::__func__.8
2 OBJECT bus.c::__func__.9
2 OBJECT cgroup.c::__func__.0
2 OBJECT class.c::__func__.0
2 OBJECT class.c::__func__.1
2 OBJECT class.c::__func__.3
2 OBJECT class.c::__func__.5
2 OBJECT class.c::__key.0
2 OBJECT class.c::__key.1
2 OBJECT class.c::__key.4
2 OBJECT core.c::__already_done.18
2 OBJECT core.c::__already_done.19
2 OBJECT core.c::__already_done.3
2 OBJECT core.c::dev_attr_size
2 OBJECT core.c::dev_attr_start
2 OBJECT core.c::dev_attr_type
2 OBJECT core.c::empty_attrs
2 OBJECT core.c::__func__.10
2 OBJECT core.c::__func__.14
2 OBJECT core.c::__func__.7
2 OBJECT core.c::__func__.9
2 OBJECT core.c::__key.0
2 OBJECT core.c::__key.2
2 OBJECT core.c::__key.3
2 OBJECT dev.c::__func__.0
2 OBJECT dir.c::__func__.3
2 OBJECT driver.c::__func__.0
2 OBJECT fib_rules.c::__msg.0
2 OBJECT file.c::__func__.2
2 OBJECT file.c::__key.1
2 OBJECT file.c::__key.2
2 OBJECT hpet.c::__func__.4
2 OBJECT icmp.c::__func__.1
2 OBJECT inode.c::__func__.1
2 OBJECT inode.c::__func__.3
2 OBJECT intel.c::__already_done.10
2 OBJECT intel.c::__already_done.11
2 OBJECT intel.c::__already_done.13
2 OBJECT ioctl.c::__func__.0
2 OBJECT iommu.c::__already_done.15
2 OBJECT iommu.c::__func__.10
2 OBJECT iommu.c::__func__.2
2 OBJECT iommu.c::_rs.13
2 OBJECT iommu.c::_rs.5
2 OBJECT iommu.c::_rs.9
2 OBJECT irq.c::__func__.0
2 OBJECT irq.c::__func__.2
2 OBJECT irqdomain.c::__func__.0
2 OBJECT irqdomain.c::__func__.1
2 OBJECT irqdomain.c::__func__.3
2 OBJECT main.c::__func__.10
2 OBJECT main.c::__func__.11
2 OBJECT main.c::__func__.3
2 OBJECT main.c::__func__.4
2 OBJECT main.c::__func__.5
2 OBJECT manage.c::__func__.1
2 OBJECT mount.c::__func__.0
2 OBJECT msr.c::__func__.0
2 OBJECT ping.c::__func__.1
2 OBJECT property.c::__func__.3
2 OBJECT qos.c::__func__.0
2 OBJECT qos.c::__func__.2
2 OBJECT resource.c::__func__.1
2 OBJECT route.c::__key.0
2 OBJECT route.c::__msg.1
2 OBJECT route.c::__msg.2
2 OBJECT route.c::__msg.3
2 OBJECT route.c::__msg.4
2 OBJECT route.c::__msg.5
2 OBJECT route.c::__msg.6
2 OBJECT swap.c::__func__.0
2 OBJECT syncookies.c::___done.1
2 OBJECT syncookies.c::msstab
2 OBJECT syncookies.c::___once_key.2
2 OBJECT sysfs.c::dev_attr_name
2 OBJECT sysfs.c::__key.1
2 OBJECT sysfs.c::power_attrs
2 OBJECT udp.c::descriptor.12
2 OBJECT udp.c::descriptor.13
2 OBJECT udp.c::__func__.2
2 OBJECT udp.c::__func__.3
2 OBJECT udp.c::__func__.4
2 OBJECT utils.c::__func__.5
3 FUNC core.c::cmask_show
3 FUNC core.c::edge_show
3 FUNC core.c::event_show
3 FUNC core.c::inv_show
3 FUNC core.c::umask_show
3 FUNC inode.c::init_once
3 OBJECT acpi.c::__func__.1
3 OBJECT core.c::format_attr_cmask
3 OBJECT core.c::format_attr_edge
3 OBJECT core.c::format_attr_event
3 OBJECT core.c::format_attr_inv
3 OBJECT core.c::format_attr_umask
3 OBJECT core.c::__func__.6
3 OBJECT core.c::__func__.8
3 OBJECT file.c::__key.3
3 OBJECT generic.c::__func__.0
3 OBJECT iommu.c::__func__.0
3 OBJECT iommu.c::__func__.1
3 OBJECT iommu.c::__func__.8
3 OBJECT main.c::__func__.0
3 OBJECT main.c::__func__.1
3 OBJECT main.c::__func__.6
3 OBJECT quirks.c::__func__.0
3 OBJECT sysfs.c::__func__.0
4 OBJECT core.c::__func__.4
5 OBJECT inode.c::tokens
6 OBJECT core.c::__func__.3
6 OBJECT core.c::__func__.5
7 OBJECT core.c::__func__.1
8 OBJECT core.c::__func__.0
8 OBJECT core.c::__func__.2
We could probably minimize the FUNC duplicates with unique names, but
I'm not as optimistic about the OBJECTs as most are created via macros
like __already_done.X. Unless clever macro magic?
Next question: what are the odds that these entries, at least the ones
we can't easily rename, need disambiguity for livepatching? or
kpatch-build for related purposes?
-- Joe
next prev parent reply other threads:[~2022-02-16 20:33 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-09 18:57 [PATCH v10 00/15] Function Granular KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 01/15] modpost: fix removing numeric suffixes Alexander Lobakin
2022-05-03 0:57 ` Masahiro Yamada
2022-05-03 7:31 ` Petr Mladek
2022-05-23 18:04 ` Masahiro Yamada
2022-05-24 11:33 ` Alexander Lobakin
2022-05-24 13:40 ` Masahiro Yamada
2022-02-09 18:57 ` [PATCH v10 02/15] livepatch: avoid position-based search if `-z unique-symbol` is available Alexander Lobakin
2022-02-11 17:41 ` Josh Poimboeuf
2022-02-11 18:05 ` Fāng-ruì Sòng
2022-02-11 18:35 ` Josh Poimboeuf
2022-02-14 12:24 ` Alexander Lobakin
2022-02-14 18:10 ` Josh Poimboeuf
2022-02-16 20:32 ` Joe Lawrence [this message]
2022-02-16 22:13 ` Josh Poimboeuf
2022-02-16 15:15 ` Miroslav Benes
2022-02-16 20:01 ` Josh Poimboeuf
2022-02-18 16:31 ` Alexander Lobakin
2022-02-18 20:08 ` Josh Poimboeuf
2022-02-14 12:14 ` Alexander Lobakin
2022-02-14 18:57 ` Josh Poimboeuf
2022-02-16 15:06 ` Miroslav Benes
2022-02-16 19:57 ` Josh Poimboeuf
2022-02-17 7:45 ` Miroslav Benes
2022-02-09 18:57 ` [PATCH v10 03/15] kallsyms: randomize /proc/kallsyms output order Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 04/15] arch: introduce asm function sections Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 05/15] x86: support " Alexander Lobakin
2022-02-11 15:45 ` Peter Zijlstra
2022-02-14 11:49 ` Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 06/15] x86: decouple ORC table sorting into a separate file Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 07/15] Makefile: add config options and build scripts for FG-KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 08/15] x86/tools: Add relative relocs for randomized functions Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 09/15] x86: Add support for function granular KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 10/15] FG-KASLR: use a scripted approach to handle .text.* sections Alexander Lobakin
2022-02-11 15:37 ` Peter Zijlstra
2022-02-14 11:34 ` Alexander Lobakin
2022-02-14 11:59 ` Peter Zijlstra
2022-02-14 12:30 ` Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 11/15] x86/boot: allow FG-KASLR to be selected Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 12/15] module: add arch-indep FG-KASLR for randomizing function layout Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 13/15] module: use a scripted approach for FG-KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 14/15] Documentation: add documentation " Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 15/15] maintainers: add MAINTAINERS entry " Alexander Lobakin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Yg1fab6h1rTjVbYO@redhat.com \
--to=joe.lawrence@redhat.com \
--cc=alexandr.lobakin@intel.com \
--cc=ardb@kernel.org \
--cc=arnd@arndb.de \
--cc=bp@alien8.de \
--cc=bruce.schlobohm@intel.com \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=davem@davemloft.net \
--cc=eshatokhin@virtuozzo.com \
--cc=hch@lst.de \
--cc=herbert@gondor.apana.org.au \
--cc=hjl.tools@gmail.com \
--cc=hpa@zytor.com \
--cc=jesse.brandeburg@intel.com \
--cc=jeyu@kernel.org \
--cc=jpoimboe@redhat.com \
--cc=keescook@chromium.org \
--cc=kristen@linux.intel.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=live-patching@vger.kernel.org \
--cc=lkp@intel.com \
--cc=llvm@lists.linux.dev \
--cc=luto@kernel.org \
--cc=masahiroy@kernel.org \
--cc=maskray@google.com \
--cc=mbenes@suse.cz \
--cc=mhiramat@kernel.org \
--cc=michal.lkml@markovi.net \
--cc=miklos@szeredi.hu \
--cc=mingo@redhat.com \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=nico@fluxnic.net \
--cc=peterz@infradead.org \
--cc=pomonis@google.com \
--cc=samitolvanen@google.com \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).