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From:   Ali Saidi <alisaidi@amazon.com>
To:     <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <x86@kernel.org>
CC:     "H. Peter Anvin" <hpa@zytor.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ali Saidi <alisaidi@amazon.com>,
        Kees Cook <keescook@chromium.org>,
        Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Will Deacon <will.deacon@arm.com>,
        "Catalin Marinas" <catalin.marinas@arm.com>,
        David Woodhouse <dwmw@amazon.co.uk>,
        Anthony Liguori <aliguori@amazon.com>
Subject: [PATCH 0/2] handle worst-case heap randomization in mmap_base
Date:   Tue, 12 Mar 2019 17:32:46 +0000
Message-ID: <20190312173248.13490-1-alisaidi@amazon.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Increase mmap_base by the worst-case brk randomization so that the stack and
heap remain apart.

In Linux 4.13 a change was committed that special cased the kernel ELF
loader when the loader is invoked directly (eab09532d400; binfmt_elf: use
ELF_ET_DYN_BASE only for PIE). Generally, the loader isn’t invoked
directly and this issue is limited to cases where it is, (e.g to set a
non-inheritable LD_LIBRARY_PATH, testing new versions of the loader). In
those rare cases, the loader doesn't take into account the amount of brk
randomization that will be applied by arch_randomize_brk(). This can
lead to the stack and heap being arbitrarily close to each other.

Ali Saidi (2):
  arm64/mmap: handle worst-case heap randomization in mmap_base
  x86/mmap: handle worst-case heap randomization in mmap_base

 arch/arm64/mm/mmap.c | 8 ++++++++
 arch/x86/mm/mmap.c   | 4 ++++
 2 files changed, 12 insertions(+)

-- 
2.15.3.AMZN