linux-kernel - Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set

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Message-ID: <21572.1491548994@warthog.procyon.org.uk>
Date:   Fri, 07 Apr 2017 08:09:54 +0100
From:   David Howells <dhowells@...hat.com>
To:     Mimi Zohar <zohar@...ux.vnet.ibm.com>
Cc:     dhowells@...hat.com, Dave Young <dyoung@...hat.com>,
        linux-kernel@...r.kernel.org,
        Matthew Garrett <mjg59@...f.ucam.org>,
        linux-efi@...r.kernel.org, gnomes@...rguk.ukuu.org.uk,
        Chun-Yi Lee <jlee@...e.com>, gregkh@...uxfoundation.org,
        kexec@...ts.infradead.org, linux-security-module@...r.kernel.org,
        keyrings@...r.kernel.org, matthew.garrett@...ula.com
Subject: Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set

Mimi Zohar <zohar@...ux.vnet.ibm.com> wrote:

> > > +	if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) && kernel_is_locked_down())
> > > +		return -EPERM;
> > > +
> > >  
> 
> IMA can be used to verify file signatures too, based on the LSM hooks
> in  kernel_read_file_from_fd().  CONFIG_KEXEC_VERIFY_SIG should not be
> required.

Okay, fair enough.  I can stick in an OR with an IS_ENABLED on some IMA
symbol.  CONFIG_IMA_KEXEC maybe?  And also require IMA be enabled?

David