kernel-hardening.lists.openwall.com archive mirror
 help / color / mirror / Atom feed
From: Kristen Carlson Accardi <kristen@linux.intel.com>
To: Kees Cook <keescook@chromium.org>
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Jessica Yu <jeyu@kernel.org>,
	arjan@linux.intel.com,  linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com,  rick.p.edgecombe@intel.com,
	Ard Biesheuvel <ardb@kernel.org>, Tony Luck <tony.luck@intel.com>
Subject: Re: [PATCH v2 9/9] module: Reorder functions
Date: Tue, 09 Jun 2020 13:59:23 -0700	[thread overview]
Message-ID: <fe529a4479b90d609937c10efb27394feda384a4.camel@linux.intel.com> (raw)
In-Reply-To: <202006091331.A94BB0DA@keescook>

On Tue, 2020-06-09 at 13:42 -0700, Kees Cook wrote:
> On Tue, Jun 09, 2020 at 01:14:04PM -0700, Kristen Carlson Accardi
> wrote:
> > On Thu, 2020-05-21 at 14:33 -0700, Kees Cook wrote:
> > > Oh! And I am reminded suddenly about CONFIG_FG_KASLR needing to
> > > interact
> > > correctly with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION in that we do
> > > NOT
> > > want the sections to be collapsed at link time:
> > 
> > sorry - I'm a little confused and was wondering if you could
> > clarify
> > something. Does this mean you expect CONFIG_FG_KASLR=y and
> > CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y to be a valid config? I am
> > not
> 
> Yes, I don't see a reason they can't be used together.
> 
> > familiar with the option, but it seems like you are saying that it
> > requires sections to be collapsed, in which case both of these
> > options
> > as yes would not be allowed? Should I actively prevent this in the
> > Kconfig?
> 
> No, I'm saying that CONFIG_LD_DEAD_CODE_DATA_ELIMINATION does _not_
> actually require that the sections be collapsed, but the Makefile
> currently does this just to keep the resulting ELF "tidy". We want
> that disabled (for the .text parts) in the case of CONFIG_FG_KASLR.
> The
> dead code elimination step, is, IIUC, done at link time before the
> output sections are written.
> 

Ah ok, that makes sense. Thanks.



  reply	other threads:[~2020-06-09 20:59 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-21 16:56 [PATCH v2 0/9] Function Granular KASLR Kristen Carlson Accardi
2020-05-21 16:56 ` [PATCH v2 1/9] objtool: Do not assume order of parent/child functions Kristen Carlson Accardi
2020-05-21 16:56 ` [PATCH v2 2/9] x86: tools/relocs: Support >64K section headers Kristen Carlson Accardi
2020-05-21 16:56 ` [PATCH v2 3/9] x86/boot: Allow a "silent" kaslr random byte fetch Kristen Carlson Accardi
2020-05-21 16:56 ` [PATCH v2 4/9] x86: Makefile: Add build and config option for CONFIG_FG_KASLR Kristen Carlson Accardi
2020-05-21 20:00   ` Kees Cook
2020-05-21 16:56 ` [PATCH v2 5/9] x86: Make sure _etext includes function sections Kristen Carlson Accardi
2020-05-21 18:11   ` Kees Cook
2020-05-21 16:56 ` [PATCH v2 6/9] x86/tools: Add relative relocs for randomized functions Kristen Carlson Accardi
2020-05-21 19:54   ` Kees Cook
2020-05-21 16:56 ` [PATCH v2 7/9] x86: Add support for function granular KASLR Kristen Carlson Accardi
2020-05-21 21:08   ` Kees Cook
2020-05-21 21:42     ` Kristen Carlson Accardi
2020-06-04 17:27     ` Kristen Carlson Accardi
2020-06-04 22:37       ` Kees Cook
2020-05-21 16:56 ` [PATCH v2 8/9] kallsyms: Hide layout Kristen Carlson Accardi
2020-05-21 21:14   ` Kees Cook
2020-05-21 16:56 ` [PATCH v2 9/9] module: Reorder functions Kristen Carlson Accardi
2020-05-21 21:33   ` Kees Cook
2020-06-09 20:14     ` Kristen Carlson Accardi
2020-06-09 20:42       ` Kees Cook
2020-06-09 20:59         ` Kristen Carlson Accardi [this message]
2020-05-21 21:54 ` [PATCH v2 0/9] Function Granular KASLR Kees Cook
2020-05-21 22:26 ` Thomas Gleixner
2020-05-21 23:30   ` Kees Cook
2020-05-21 23:43     ` Thomas Gleixner
2020-05-21 23:44     ` Kristen Carlson Accardi

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=fe529a4479b90d609937c10efb27394feda384a4.camel@linux.intel.com \
    --to=kristen@linux.intel.com \
    --cc=ardb@kernel.org \
    --cc=arjan@linux.intel.com \
    --cc=bp@alien8.de \
    --cc=hpa@zytor.com \
    --cc=jeyu@kernel.org \
    --cc=keescook@chromium.org \
    --cc=kernel-hardening@lists.openwall.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=rick.p.edgecombe@intel.com \
    --cc=tglx@linutronix.de \
    --cc=tony.luck@intel.com \
    --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).