linux-kernel - Re: [PATCH v5] fs: make dumpable=2 require fully qualified path

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Message-ID: <CAGXu5jL8XpkWhFkWtdQA7egR+pOmu5TVjK7NTzeVEr=sqcmePw@mail.gmail.com>
Date:	Mon, 25 Jun 2012 15:20:19 -0700
From:	Kees Cook <keescook@...omium.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, Rob Landley <rob@...dley.net>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Alan Cox <alan@...ux.intel.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Doug Ledford <dledford@...hat.com>,
	Serge Hallyn <serge.hallyn@...onical.com>,
	James Morris <james.l.morris@...cle.com>,
	Joe Korty <joe.korty@...r.com>, linux-doc@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v5] fs: make dumpable=2 require fully qualified path

On Mon, Jun 25, 2012 at 3:14 PM, Andrew Morton
<akpm@...ux-foundation.org> wrote:
> On Mon, 25 Jun 2012 11:03:27 -0700
> Kees Cook <keescook@...omium.org> wrote:
>
>> Instead of introducing a suid_dumpable=3 mode and breaking all users
>> of mode 2, this only disables the unsafe portion of mode 2 (writing to
>> disk via relative path).
>
> It would be nicer to generate the warning at configuration time rather than
> at core-dumping time.  I have a feeling that's Hard To Do, but why?

I actually feel that this is much more discoverable because anyone
trying to figure out why a crash isn't dumping core isn't going to be
looking back in time through their dmesg to find the warning from
setting the sysctl. Additionally, I think it's the same kind of thing
that the other existing "Skipping core dump" printk messages are
reporting.

-Kees

-- 
Kees Cook
Chrome OS Security
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