From: Kees Cook <kees.cook@canonical.com>
To: Joe Perches <joe@perches.com>
Cc: linux-kernel@vger.kernel.org,
Rusty Russell <rusty@rustcorp.com.au>, Tejun Heo <tj@kernel.org>,
Marcus Meissner <meissner@suse.de>,
Jason Wessel <jason.wessel@windriver.com>,
Eugene Teo <eugeneteo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Bjorn Helgaas <bjorn.helgaas@hp.com>,
Len Brown <len.brown@intel.com>, Changli Gao <xiaosuo@gmail.com>,
Dan Rosenberg <drosenberg@vsecurity.com>
Subject: Re: RFC: introduce "K" flag for printf, similar to %pK
Date: Tue, 25 Jan 2011 09:28:41 -0800 [thread overview]
Message-ID: <20110125172841.GY4979@outflux.net> (raw)
In-Reply-To: <1295921824.14459.28.camel@Joe-Laptop>
Hi Joe,
On Mon, Jan 24, 2011 at 06:17:04PM -0800, Joe Perches wrote:
> On Mon, 2011-01-24 at 18:03 -0800, Kees Cook wrote:
> > In the interests of hiding kernel addresses from userspace (without
> > messing with file permissions), I want to use %pK for /proc/kallsyms and
> > /proc/modules, but this results in changing several %x's to %p's. The
> > primary side-effects is that some legitimately "0" value things in
> > /proc/kallsyms turn into "(null)".
>
> Another option would be to allow '0' for
> kernel pointers.
But then this changes the behavior of %p where (null) is expected. (i.e.
when switching from %p to %pK.)
I'm personally fine with that, as I suspect anything parsing the output
that can handle finding "(null)" will be fine with "0" too. But the other
way around, not so much. :)
-Kees
--
Kees Cook
Ubuntu Security Team
next prev parent reply other threads:[~2011-01-25 17:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-25 2:03 RFC: introduce "K" flag for printf, similar to %pK Kees Cook
2011-01-25 2:04 ` [PATCH 1/2] use %pK for /proc/kallsyms and /proc/modules Kees Cook
2011-01-25 2:07 ` [PATCH 2/2] use %pK and %Klx " Kees Cook
2011-01-25 2:17 ` RFC: introduce "K" flag for printf, similar to %pK Joe Perches
2011-01-25 17:28 ` Kees Cook [this message]
2011-01-25 17:41 ` Joe Perches
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