From: Rik van Riel <riel@redhat.com>
To: Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Daniel Micay <danielmicay@gmail.com>,
Qualys Security Advisory <qsa@qualys.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Alexander Viro <viro@zeniv.linux.org.uk>,
Dmitry Safonov <dsafonov@virtuozzo.com>,
Andy Lutomirski <luto@amacapital.net>,
Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
kernel-hardening@lists.openwall.com
Subject: [kernel-hardening] Re: [PATCH v2] binfmt_elf: Use ELF_ET_DYN_BASE only for PIE
Date: Wed, 21 Jun 2017 14:24:26 -0400 [thread overview]
Message-ID: <1498069466.13083.20.camel@redhat.com> (raw)
In-Reply-To: <20170621173201.GA114489@beast>
On Wed, 2017-06-21 at 10:32 -0700, Kees Cook wrote:
> To allow for a lower ELF_ET_DYN_BASE, loaders (ET_DYN without INTERP)
> are loaded into the mmap region, leaving space available for either
> an
> ET_EXEC binary with a fixed location or PIE being loaded into mmap by
> the
> loader. Only PIE programs are loaded offset from ELF_ET_DYN_BASE,
> which
> means architectures can now safely lower their values without risk of
> loaders colliding with their subsequently loaded programs.
>
> For 64-bit, ELF_ET_DYN_BASE is best set to 4GB to allow runtimes to
> use
> the entire 32-bit address space for 32-bit pointers.
>
> Thanks to PaX Team, Daniel Micay, and Rik van Riel for inspiration
> and
> suggestions on how to implement this solution.
>
> Fixes: d1fd836dcf00 ("mm: split ET_DYN ASLR from mmap ASLR")
> Cc: stable@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Rik van Riel <riel@redhat.com>
next prev parent reply other threads:[~2017-06-21 18:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-21 17:32 [kernel-hardening] [PATCH v2] binfmt_elf: Use ELF_ET_DYN_BASE only for PIE Kees Cook
2017-06-21 18:24 ` Rik van Riel [this message]
2017-06-27 14:49 ` [kernel-hardening] " Michal Hocko
2017-06-27 14:54 ` Daniel Micay
2017-06-27 20:08 ` Kees Cook
2017-07-04 13:12 ` Michal Hocko
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