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From: Andy Lutomirski <luto@amacapital.net>
Date: Fri, 4 Oct 2013 16:08:06 -0700
Message-ID: <CALCETrXa1uAAOM7U_Jk1APHx1aJGdJJy4ggJ9C+sn++btXX2FA@mail.gmail.com>
Subject: Re: [PATCH v2 2/9] procfs: add proc_allow_access() to check if file's
 opener may access task
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Djalal Harouni <tixxdz@opendz.org>, Kees Cook <keescook@chromium.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        "Serge E. Hallyn" <serge.hallyn@ubuntu.com>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        David Rientjes <rientjes@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        "kernel-hardening@lists.openwall.com" 
	<kernel-hardening@lists.openwall.com>,
        Djalal Harouni <tixxdz@gmail.com>
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On Fri, Oct 4, 2013 at 3:59 PM, Andy Lutomirski <luto@amacapital.net> wrote:
>
> I'd really like a solution where there are no read or write
> implementations in the entire kernel that check permissions.  Failing
> that, just getting it for procfs would be nice.  (uid_map, etc will
> probably need to be revoked on unshare for this to work.)

By "check permissions" I mean using anything but f_cred.

uid_map won't need any form of revoke, though -- the stuct file
already points at a particular target ns.  I wonder why the
CAP_SYS_ADMIN check is in map_write instead of open, though.

--Andy
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