From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Theodore Y. Ts'o" <tytso@mit.edu>
Subject: Re: [RFC PATCH v2 0/2] Randomization of address chosen by mmap.
Date: Tue, 27 Mar 2018 18:16:35 -0400
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To: Ilya Smith <blackzert@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>, Matthew Wilcox <willy@infradead.org>, rth@twiddle.net, ink@jurassic.park.msu.ru, mattst88@gmail.com, vgupta@synopsys.com, linux@armlinux.org.uk, tony.luck@intel.com, fenghua.yu@intel.com, ralf@linux-mips.org, jejb@parisc-linux.org, Helge Deller <deller@gmx.de>, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, nyc@holomorphy.com, viro@zeniv.linux.org.uk, arnd@arndb.de, gregkh@linuxfoundation.org, deepa.kernel@gmail.com, Hugh Dickins <hughd@google.com>, kstewart@linuxfoundation.org, pombredanne@nexb.com, Andrew Morton <akpm@linux-foundation.org>

On Tue, Mar 27, 2018 at 04:51:08PM +0300, Ilya Smith wrote:
> > /dev/[u]random is not sufficient?
> 
> Using /dev/[u]random makes 3 syscalls - open, read, close. This is a performance
> issue.

You may want to take a look at the getrandom(2) system call, which is
the recommended way getting secure random numbers from the kernel.

> > Well, I am pretty sure userspace can implement proper free ranges
> > tracking…
> 
> I think we need to know what libc developers will say on implementing ASLR in 
> user-mode. I am pretty sure they will say ‘nether’ or ‘some-day’. And problem 
> of ASLR will stay forever.

Why can't you send patches to the libc developers?

Regards,

						- Ted