linux-kernel - Re: [PATCH v5 next 0/5] Improve Module autoloading infrastructure

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Message-ID: <alpine.LFD.2.20.1711281041040.13133@localhost>
Date:   Tue, 28 Nov 2017 10:44:52 +1100 (AEDT)
From:   James Morris <james.l.morris@...cle.com>
To:     Kees Cook <keescook@...omium.org>
cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        David Miller <davem@...emloft.net>,
        Djalal Harouni <tixxdz@...il.com>,
        Andy Lutomirski <luto@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Ben Hutchings <ben.hutchings@...ethink.co.uk>,
        Solar Designer <solar@...nwall.com>,
        "Serge E. Hallyn" <serge@...lyn.com>, Jessica Yu <jeyu@...nel.org>,
        Rusty Russell <rusty@...tcorp.com.au>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-security-module <linux-security-module@...r.kernel.org>,
        kernel-hardening@...ts.openwall.com,
        Jonathan Corbet <corbet@....net>,
        Ingo Molnar <mingo@...nel.org>,
        Network Development <netdev@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH v5 next 0/5] Improve Module autoloading infrastructure

On Mon, 27 Nov 2017, Kees Cook wrote:

> >         if (WARN_ON_ONCE(!capable(CAP_SYS_MODULE) ||
> >                          !capable(CAP_SYS_ADMIN) ||
> >                          !capable(CAP_NET_ADMIN) ||
> >                          !unprivileged_autoload(module_name)))

(Side note: the capable() calls would ideally come after the whitelist 
check).

> We have some of this already with the module prefixes. Doing this
> per-module would need to be exported to userspace, I think. It'd be
> way too fragile sitting in the kernel.

What about writing a whitelist to /proc (per-task) or /sys/fs (global) ?

The per-task whitelist is inherited from the global one by default, or 
from a parent process if it's been modified in the parent.


-- 
James Morris
<james.l.morris@...cle.com>