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Date:      Sun, 4 Dec 2011 15:57:06 +0000
From:      "Robert N. M. Watson" <rwatson@freebsd.org>
To:        Jilles Tjoelker <jilles@stack.nl>
Cc:        Mikolaj Golub <trociny@freebsd.org>, Kostik Belousov <kostikbel@gmail.com>, freebsd-hackers@freebsd.org
Subject:   Re: "ps -e" without procfs(5)
Message-ID:  <1E0AAB37-952A-49B4-94AF-B67B84E6957B@freebsd.org>
In-Reply-To: <20111204143145.GA44832@stack.nl>
References:  <86y5wkeuw9.fsf@kopusha.home.net> <20111016171005.GB50300@deviant.kiev.zoral.com.ua> <86aa8qozyx.fsf@kopusha.home.net> <20111025082451.GO50300@deviant.kiev.zoral.com.ua> <86aa8k2im0.fsf@kopusha.home.net> <20111204143145.GA44832@stack.nl>

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On 4 Dec 2011, at 14:31, Jilles Tjoelker wrote:

> On Sat, Oct 29, 2011 at 01:32:39PM +0300, Mikolaj Golub wrote:
>> [KERN_PROC_AUXV requires just p_cansee()]
>=20
> If we are ever going to do ASLR, the AUXV information tells an =
attacker
> where the stack, executable and RTLD are located, which defeats much =
of
> the point of randomizing the addresses in the first place.
>=20
> Given that the AUXV information seems to be used by debuggers only
> anyway, I think it would be good to move it to p_candebug() now.
>=20
> The full virtual memory maps (KERN_PROC_VMMAP, procstat -v) are =
already
> under p_candebug().


Agreed. In general, my view is that p_cansee() should be used for very =
few of our process inspection APIs. I like your example of ASLR =
especially, as it illustrates how debugging information can aid even =
local attacks (i.e., user vs. setuid binary).

Robert=



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