From: Kristen Carlson Accardi <kristen@linux.intel.com>
To: Kees Cook <keescook@chromium.org>, Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Miroslav Benes <mbenes@suse.cz>,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
arjan@linux.intel.com, x86@kernel.org,
linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com,
live-patching@vger.kernel.org
Subject: Re: [PATCH v4 00/10] Function Granular KASLR
Date: Wed, 22 Jul 2020 12:56:10 -0700 [thread overview]
Message-ID: <301c7fb7d22ad6ef97856b421873e32c2239d412.camel@linux.intel.com> (raw)
In-Reply-To: <202007221241.EBC2215A@keescook>
On Wed, 2020-07-22 at 12:42 -0700, Kees Cook wrote:
> On Wed, Jul 22, 2020 at 11:07:30AM -0500, Josh Poimboeuf wrote:
> > On Wed, Jul 22, 2020 at 07:39:55AM -0700, Kees Cook wrote:
> > > On Wed, Jul 22, 2020 at 11:27:30AM +0200, Miroslav Benes wrote:
> > > > Let me CC live-patching ML, because from a quick glance this is
> > > > something
> > > > which could impact live patching code. At least it invalidates
> > > > assumptions
> > > > which "sympos" is based on.
> > >
> > > In a quick skim, it looks like the symbol resolution is using
> > > kallsyms_on_each_symbol(), so I think this is safe? What's a good
> > > selftest for live-patching?
> >
> > The problem is duplicate symbols. If there are two static
> > functions
> > named 'foo' then livepatch needs a way to distinguish them.
> >
> > Our current approach to that problem is "sympos". We rely on the
> > fact
> > that the second foo() always comes after the first one in the
> > symbol
> > list and kallsyms. So they're referred to as foo,1 and foo,2.
>
> Ah. Fun. In that case, perhaps the LTO series has some solutions. I
> think builds with LTO end up renaming duplicate symbols like that, so
> it'll be back to being unique.
>
Well, glad to hear there might be some precendence for how to solve
this, as I wasn't able to think of something reasonable off the top of
my head. Are you speaking of the Clang LTO series?
https://lore.kernel.org/lkml/20200624203200.78870-1-samitolvanen@google.com/
next prev parent reply other threads:[~2020-07-22 19:56 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 16:59 [PATCH v4 00/10] Function Granular KASLR Kristen Carlson Accardi
2020-07-17 16:59 ` [PATCH v4 01/10] objtool: Do not assume order of parent/child functions Kristen Carlson Accardi
2020-07-17 16:59 ` [PATCH v4 02/10] x86: tools/relocs: Support >64K section headers Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 03/10] x86/boot: Allow a "silent" kaslr random byte fetch Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 04/10] x86: Makefile: Add build and config option for CONFIG_FG_KASLR Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 05/10] x86: Make sure _etext includes function sections Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 06/10] x86/tools: Add relative relocs for randomized functions Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 07/10] x86/boot/compressed: Avoid duplicate malloc() implementations Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 08/10] x86: Add support for function granular KASLR Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 09/10] kallsyms: Hide layout Kristen Carlson Accardi
2020-07-20 1:25 ` Kees Cook
2020-07-20 16:59 ` Kristen Carlson Accardi
2020-07-17 17:00 ` [PATCH v4 10/10] module: Reorder functions Kristen Carlson Accardi
2020-07-28 17:29 ` Jessica Yu
2020-07-22 9:27 ` [PATCH v4 00/10] Function Granular KASLR Miroslav Benes
2020-07-22 14:39 ` Kees Cook
2020-07-22 14:51 ` Joe Lawrence
2020-07-22 14:56 ` Joe Lawrence
2020-07-22 18:24 ` Kristen Carlson Accardi
2020-07-22 16:07 ` Josh Poimboeuf
2020-07-22 19:42 ` Kees Cook
2020-07-22 19:56 ` Kristen Carlson Accardi [this message]
2020-07-22 21:33 ` Josh Poimboeuf
2020-08-21 23:02 ` Kristen Carlson Accardi
2020-08-25 16:16 ` Joe Lawrence
2020-08-28 10:21 ` Miroslav Benes
2020-08-28 19:24 ` Josh Poimboeuf
2021-01-23 22:59 ` Fangrui Song
2021-01-25 17:21 ` Josh Poimboeuf
2020-08-03 11:39 ` Evgenii Shatokhin
2020-08-03 17:45 ` Kees Cook
2020-08-03 18:17 ` Joe Lawrence
2020-08-03 19:38 ` Frank Ch. Eigler
2020-08-03 20:11 ` Kees Cook
2020-08-03 21:12 ` Frank Ch. Eigler
2020-08-03 21:41 ` Kees Cook
2020-08-04 0:48 ` Frank Ch. Eigler
2020-08-04 17:04 ` Jessica Yu
2020-08-04 18:23 ` Joe Lawrence
2020-08-07 16:38 ` Kristen Carlson Accardi
2020-08-07 17:20 ` Kees Cook
2020-08-10 16:10 ` Kristen Carlson Accardi
2020-08-12 17:18 ` Kristen Carlson Accardi
2020-08-06 15:32 ` Ingo Molnar
2020-08-06 19:24 ` Kristen Carlson Accardi
2020-08-06 19:27 ` Kees Cook
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