From: Daniel Micay <danielmicay@gmail.com>
To: Kostya Serebryany <kcc@google.com>, Kees Cook <keescook@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Rik van Riel <riel@redhat.com>, Reid Kleckner <rnk@google.com>,
Peter Collingbourne <pcc@google.com>,
eugenis@google.com
Subject: Re: binfmt_elf: use ELF_ET_DYN_BASE only for PIE breaks asan
Date: Mon, 07 Aug 2017 14:45:56 -0400 [thread overview]
Message-ID: <1502131556.1803.10.camel@gmail.com> (raw)
In-Reply-To: <1502131092.1803.8.camel@gmail.com>
> There are currently other issues. Try:
>
> sysctl vm.mmap_rnd_bits=32
> sysctl vm.mmap_rnd_compat_bits=16
>
> IIRC that breaks some sanitizers at least for 32-bit executables.
Also, stack mapping rand isn't yet tied to that sysctl but is rather
hard-wired to 11 bits on 32-bit and 20 bits (IIRC) on 64-bit. Once it's
tied to the sysctl (or a different sysctl, if keeping the same defaults
is desired) that will be able to use significantly more address space.
It might be setting it to the maximum + better stack rand that breaks
sanitizers, rather than just setting the entropy higher.
If anyone wants to test some other changes though...
https://github.com/copperhead/linux-hardened/commit/31ebed471d31a437cc551b1bfae03c9e7f58117d.patch
https://github.com/copperhead/linux-hardened/commit/073329e7b541b89172833f61fb84d81f32389d6e.patch
They haven't been submitted for inclusion upstream, but that's the plan:
reaching parity with the ASLR PaX has provided for years when the
entropy values are set to max.
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next prev parent reply other threads:[~2017-08-07 18:45 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-07 17:24 binfmt_elf: use ELF_ET_DYN_BASE only for PIE breaks asan Dmitry Vyukov
2017-08-07 17:33 ` Kostya Serebryany
2017-08-07 17:33 ` Kees Cook
2017-08-07 18:26 ` Kostya Serebryany
2017-08-07 18:36 ` Evgenii Stepanov
2017-08-07 18:40 ` Kees Cook
2017-08-07 18:51 ` Evgenii Stepanov
2017-08-07 18:57 ` Kees Cook
2017-08-07 19:03 ` Kostya Serebryany
2017-08-07 19:06 ` Kees Cook
2017-08-07 19:10 ` Kostya Serebryany
2017-08-07 19:24 ` Kees Cook
2017-08-07 19:32 ` Kostya Serebryany
2017-08-07 19:12 ` Evgenii Stepanov
2017-08-07 18:38 ` Daniel Micay
2017-08-07 18:45 ` Daniel Micay [this message]
2017-08-07 18:39 ` Kees Cook
2017-08-07 18:48 ` Daniel Micay
2017-08-07 18:52 ` Kees Cook
2017-08-07 18:56 ` Kostya Serebryany
2017-08-07 18:59 ` Kees Cook
2017-08-07 19:01 ` Daniel Micay
2017-08-07 19:05 ` Kostya Serebryany
2017-08-07 19:12 ` Kees Cook
2017-08-07 19:16 ` Kostya Serebryany
2017-08-07 19:21 ` Kees Cook
2017-08-07 19:26 ` Kostya Serebryany
2017-08-07 19:34 ` Kees Cook
2017-08-07 19:40 ` Kostya Serebryany
2017-08-07 19:42 ` Daniel Micay
2017-08-07 19:46 ` Kees Cook
2017-08-07 18:21 ` Daniel Micay
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