From: "H. Peter Anvin" <hpa@zytor.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org, x86@kernel.org,
kernel-hardening@lists.openwall.com, adurbin@google.com,
Eric Northup <digitaleric@google.com>,
jln@google.com, wad@google.com,
Mathias Krause <minipli@googlemail.com>,
Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v6 0/7] Kernel base address randomization
Date: Tue, 01 Oct 2013 22:30:58 -0700 [thread overview]
Message-ID: <524BAF92.1090705@zytor.com> (raw)
In-Reply-To: <20131002052531.GA31122@gmail.com>
On 10/01/2013 10:25 PM, Ingo Molnar wrote:
>
> I mean, for example in an oops message we print data in words: the RIP,
> other registers and stack contents. If any of these values lies within the
> randomization range then we could de-randomize it.
>
> So instead of exposing randomized values, we could expose de-randomized
> values.
>
> ( This isn't fool-proof: if some data value happens to lie within the
> random range spuriously then we'll incorrectly transform it. In the
> context of oops messages this should not be a big practical problem
> though. )
>
I don't agree that this isn't a big practical problem. I often find it
necessary to pick out "things that look like pointers". Overall,
derandomization would make it possible to get really confused when you
have things like half a pointer overwritten.
-hpa
next prev parent reply other threads:[~2013-10-02 5:32 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-01 19:37 Kees Cook
2013-10-01 19:37 ` [PATCH 1/7] x86, kaslr: move CPU flags out of cpucheck Kees Cook
2013-10-01 20:48 ` H. Peter Anvin
2013-10-01 21:09 ` Kees Cook
2013-10-01 19:37 ` [PATCH 2/7] x86, kaslr: return location from decompress_kernel Kees Cook
2013-10-01 19:37 ` [PATCH 3/7] x86, kaslr: find minimum safe relocation position Kees Cook
2013-10-01 19:37 ` [PATCH 4/7] x86, kaslr: select random base offset Kees Cook
2013-10-01 20:46 ` H. Peter Anvin
2013-10-01 21:18 ` Kees Cook
2013-10-01 19:37 ` [PATCH 5/7] x86, kaslr: select memory region from e820 maps Kees Cook
2013-10-01 19:37 ` [PATCH 6/7] x86, kaslr: report kernel offset on panic Kees Cook
2013-10-02 0:38 ` HATAYAMA Daisuke
2013-10-02 1:06 ` HATAYAMA Daisuke
2013-10-02 7:51 ` Kees Cook
2013-10-02 7:48 ` Kees Cook
2013-10-02 9:13 ` HATAYAMA Daisuke
2013-10-03 0:33 ` HATAYAMA Daisuke
2013-10-03 13:47 ` Dave Anderson
2013-10-07 1:59 ` HATAYAMA Daisuke
2013-10-07 13:21 ` Dave Anderson
2013-10-08 9:52 ` HATAYAMA Daisuke
2013-10-08 13:38 ` Dave Anderson
2013-10-09 10:04 ` HATAYAMA Daisuke
2013-10-09 14:13 ` H. Peter Anvin
2013-10-09 18:06 ` Kees Cook
2013-10-01 19:37 ` [PATCH 7/7] x86, kaslr: raise max positions to 1GiB on x86_64 Kees Cook
2013-10-02 5:07 ` [PATCH v6 0/7] Kernel base address randomization Ingo Molnar
2013-10-02 5:11 ` H. Peter Anvin
2013-10-02 5:25 ` Ingo Molnar
2013-10-02 5:30 ` H. Peter Anvin [this message]
2013-10-02 5:36 ` Kees Cook
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