Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [RFC PATCH] Randomization of address chosen by mmap.
To:     Kees Cook <keescook@chromium.org>, Ilya Smith <blackzert@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Michal Hocko <mhocko@suse.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Jan Kara <jack@suse.cz>, Jerome Glisse <jglisse@redhat.com>,
        Hugh Dickins <hughd@google.com>,
        Matthew Wilcox <willy@infradead.org>,
        Helge Deller <deller@gmx.de>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Oleg Nesterov <oleg@redhat.com>, Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Kernel Hardening <kernel-hardening@lists.openwall.com>
References: <20180227131338.3699-1-blackzert@gmail.com>
 <CAGXu5jKF7ysJqj57ZktrcVL4G2NWOFHCud8dtXFHLs=tvVLXnQ@mail.gmail.com>
From:   lazytyped <lazytyped@gmail.com>
Message-ID: <089e9c52-f623-085a-4d8b-d91cfc6a3608@gmail.com>
Date:   Tue, 27 Feb 2018 22:31:38 +0100
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0)
 Gecko/20100101 Thunderbird/52.6.0
MIME-Version: 1.0
In-Reply-To: <CAGXu5jKF7ysJqj57ZktrcVL4G2NWOFHCud8dtXFHLs=tvVLXnQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 2/27/18 9:52 PM, Kees Cook wrote:
> I'd like more details on the threat model here; if it's just a matter
> of .so loading order, I wonder if load order randomization would get a
> comparable level of uncertainty without the memory fragmentation,

This also seems to assume that leaking the address of one single library
isn't enough to mount a ROP attack to either gain enough privileges or
generate a primitive that can leak further information. Is this really
the case? Do you have some further data around this?


       -  twiz