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Subject: Re: [PATCH] LSM: allow an LSM to disable all hooks at once
To:     James Morris <jmorris@namei.org>,
        Ondrej Mosnacek <omosnace@redhat.com>
Cc:     Linux Security Module list 
        <linux-security-module@vger.kernel.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Casey Schaufler <casey@schaufler-ca.com>,
        SElinux list <selinux@vger.kernel.org>,
        Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <sds@tycho.nsa.gov>,
        John Johansen <john.johansen@canonical.com>,
        Kees Cook <keescook@chromium.org>,
        Micah Morton <mortonm@chromium.org>
References: <20191211140833.939845-1-omosnace@redhat.com>
 <66706222-b6af-5099-e485-b99391ad70b3@i-love.sakura.ne.jp>
 <CAFqZXNv=AnPxHuQCusoJQGEJ8Q+yF7_TPBCRyAcE5OPzoYFc9w@mail.gmail.com>
 <alpine.LRH.2.21.1912140547490.9693@namei.org>
From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
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Date:   Sat, 14 Dec 2019 09:32:01 +0900
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On 2019/12/14 3:48, James Morris wrote:
> On Thu, 12 Dec 2019, Ondrej Mosnacek wrote:
> 
>> I'd say the burden of implementing this would lie on the arms of
>> whoever prepares the patches for dynamic load/unload.
> 
> Correct, and I don't see any such patches being accepted.
> 
> Go and look at some exploits, where LSM is used as a rootkit API...
> 

Evaluating trust of LSM modules is a job of module signing / integrity
checking etc. Disallowing loadable LSM modules (because of worrying
about rootkit API) is as stupid as enforcing CONFIG_MODULES=n.