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

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Message-ID: <alpine.LFD.2.20.1711280924350.11830@localhost>
Date:   Tue, 28 Nov 2017 09:31:18 +1100 (AEDT)
From:   James Morris <james.l.morris@...cle.com>
To:     David Miller <davem@...emloft.net>
cc:     torvalds@...ux-foundation.org, tixxdz@...il.com,
        keescook@...omium.org, luto@...nel.org, akpm@...ux-foundation.org,
        mcgrof@...nel.org, ben.hutchings@...ethink.co.uk,
        solar@...nwall.com, serge@...lyn.com, jeyu@...nel.org,
        rusty@...tcorp.com.au, linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        kernel-hardening@...ts.openwall.com, corbet@....net,
        mingo@...nel.org, netdev@...r.kernel.org, peterz@...radead.org
Subject: Re: [PATCH v5 next 0/5] Improve Module autoloading infrastructure

On Tue, 28 Nov 2017, David Miller wrote:

> From: Linus Torvalds <torvalds@...ux-foundation.org>
> Date: Mon, 27 Nov 2017 10:41:30 -0800
> 
> > What are the real life use-cases for normal users having modules
> > auto-load?
> 
> User opens SCTP socket, SCTP protocol module loads.
> 
> People build test cases via namespaces, and in that namespaces normal
> users can setup virtual tunnel devices themselves, and those configure
> operations can bring the tunnel module in.

What about implementing a white list of modules which are able to be 
loaded by unprivileged users?

Then, Linus' solution would look something like:

	va_start(args, fmt);
	ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);
	va_end(args);

	if (WARN_ON_ONCE(!capable(CAP_SYS_MODULE) ||
                         !capable(CAP_SYS_ADMIN) ||
                         !capable(CAP_NET_ADMIN) ||
                         !unprivileged_autoload(module_name)))
		return -EPERM;



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