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From: Andy Lutomirski <luto@kernel.org>
To: Kees Cook <keescook@google.com>
Cc: Solar Designer <solar@openwall.com>,
	Djalal Harouni <tixxdz@gmail.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	"kernel-hardening@lists.openwall.com"
	<kernel-hardening@lists.openwall.com>,
	Andy Lutomirski <luto@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Jessica Yu <jeyu@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	James Morris <james.l.morris@oracle.com>,
	Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [kernel-hardening] [PATCH v4 next 0/3] modules: automatic module loading restrictions
Date: Tue, 23 May 2017 12:50:25 -0700	[thread overview]
Message-ID: <CALCETrXiaBweijZ22Lwb_pQY934ejcXtEG2EW3nRxe7cEx7PDw@mail.gmail.com> (raw)
In-Reply-To: <CAGXu5jJ-zpqU9v44=bc0GnQP5zcKtceR_7DBQVBZ=vy3OvNx9w@mail.gmail.com>

On Tue, May 23, 2017 at 11:36 AM, Kees Cook <keescook@google.com> wrote:
> On Tue, May 23, 2017 at 12:48 AM, Solar Designer <solar@openwall.com> wrote:
>> For modules_autoload_mode=2, we already seem to have the equivalent of
>> modprobe=/bin/true (or does it differ subtly, maybe in return values?),
>> which I already use at startup on a GPU box like this (preloading
>> modules so that the OpenCL backends wouldn't need the autoloading):
>>
>> nvidia-smi
>> nvidia-modprobe -u -c=0
>> #modprobe nvidia_uvm
>> #modprobe fglrx
>>
>> sysctl -w kernel.modprobe=/bin/true
>> sysctl -w kernel.hotplug=/bin/true
>>
>> but it's good to also have this supported more explicitly and more
>> consistently through modules_autoload_mode=2 while we're at it.  So I
>> support having this mode as well.  I just question the need to have it
>> non-resettable.
>
> I agree it's useful to have the explicit =2 state just to avoid
> confusion when more systems start implementing
> CONFIG_STATIC_USERMODEHELPER and kernel.modprobe becomes read-only
> (though the userspace implementation may allow for some way to disable
> it, etc). I just like avoiding the upcall to modprobe at all.

I fully support =2 to mean "no automatic loading at all".  I dislike
making it non-resettable.  If you can write to sysctls, then, most
likely you can either call init_module() directly or the system has
module loading disabled entirely.

  reply	other threads:[~2017-05-23 19:50 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-22 11:57 [PATCH v4 next 0/3] modules: automatic module loading restrictions Djalal Harouni
2017-05-22 11:57 ` [PATCH v4 next 1/3] modules:capabilities: allow __request_module() to take a capability argument Djalal Harouni
2017-05-22 22:20   ` Kees Cook
2017-05-23 10:29     ` Djalal Harouni
2017-05-23 19:19       ` Kees Cook
2017-05-24 14:16         ` Djalal Harouni
2017-05-30 17:59           ` Kees Cook
2017-06-01 14:56             ` Djalal Harouni
2017-06-01 19:10               ` Kees Cook
2017-09-02  6:31                 ` Djalal Harouni
2017-05-22 11:57 ` [PATCH v4 next 2/3] modules:capabilities: automatic module loading restriction Djalal Harouni
2017-05-22 22:28   ` Kees Cook
2017-05-22 11:57 ` [PATCH v4 next 3/3] modules:capabilities: add a per-task modules auto-load mode Djalal Harouni
2017-05-23 14:18   ` kbuild test robot
2017-05-22 12:08 ` [PATCH v4 next 0/3] modules: automatic module loading restrictions Solar Designer
     [not found]   ` <20170522120848.GA3003-cxoSlKxDwOJWk0Htik3J/w@public.gmane.org>
2017-05-22 13:49     ` [kernel-hardening] " Djalal Harouni
     [not found]       ` <CAEiveUdqfMk4+vLg6TaEJNSGwoQHxYq0P4aqZoL4i9GgR3Vdtw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-22 16:43         ` Solar Designer
     [not found]           ` <20170522164323.GA2048-cxoSlKxDwOJWk0Htik3J/w@public.gmane.org>
2017-05-22 19:55             ` Djalal Harouni
2017-05-22 23:07               ` Kees Cook
2017-05-22 23:38                 ` Andy Lutomirski
2017-05-22 23:52                   ` Kees Cook
2017-05-23 13:02                   ` Djalal Harouni
2017-05-23  7:48                 ` [kernel-hardening] " Solar Designer
     [not found]                   ` <20170523074808.GA4562-cxoSlKxDwOJWk0Htik3J/w@public.gmane.org>
2017-05-23 18:36                     ` Kees Cook
2017-05-23 19:50                       ` Andy Lutomirski [this message]
2017-05-24 18:06                   ` Djalal Harouni

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