Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [RFC PATCH 2/2] kexec, KEYS: Make use of platform keyring for
 signature verify
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Dave Young <dyoung@redhat.com>
Cc:     Kairui Song <kasong@redhat.com>, linux-kernel@vger.kernel.org,
        dhowells@redhat.com, dwmw2@infradead.org,
        jwboyer@fedoraproject.org, keyrings@vger.kernel.org,
        jmorris@namei.org, serge@hallyn.com, bauerman@linux.ibm.com,
        ebiggers@google.com, nayna@linux.ibm.com,
        linux-integrity@vger.kernel.org, kexec@lists.infradead.org
Date:   Mon, 14 Jan 2019 11:10:51 -0500
In-Reply-To: <20190113013958.GA14019@dhcp-128-65.nay.redhat.com>
References: <20190109164824.19708-1-kasong@redhat.com>
         <20190109164824.19708-3-kasong@redhat.com>
         <20190111134303.GA12760@dhcp-128-65.nay.redhat.com>
         <1547223220.19931.471.camel@linux.ibm.com>
         <20190113013958.GA14019@dhcp-128-65.nay.redhat.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 8bit
Message-Id: <1547482251.4156.127.camel@linux.ibm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sun, 2019-01-13 at 09:39 +0800, Dave Young wrote:
> Hi,
> 
> On 01/11/19 at 11:13am, Mimi Zohar wrote:
> > On Fri, 2019-01-11 at 21:43 +0800, Dave Young wrote:
> > [snip]
> > 
> > > Personally I would like to see platform key separated from integrity.
> > > But for the kexec_file part I think it is good at least it works with
> > > this fix.
> > > 
> > > Acked-by: Dave Young <dyoung@redhat.com>
> > 
> > The original "platform" keyring patches that Nayna posted multiple
> > times were in the certs directory, but nobody commented/responded.  So
> > she reworked the patches, moving them to the integrity directory and
> > posted them (cc'ing the kexec mailing list).  It's a bit late to be
> > asking to move it, isn't it?
> 
> Hmm, apologize for being late,  I did not get chance to have a look the
> old series.  Since we have the needs now, it should be still fine
> 
> Maybe Kairui can check Nayna's old series, see if he can do something
> again?

Whether the platform keyring is defined in certs/ or in integrity/ the
keyring id needs to be accessible to the other, without making the
keyring id global.  Moving where the platform keyring is defined is
not the problem.

Commit a210fd32a46b ("kexec: add call to LSM hook in original
kexec_load syscall") introduced a new LSM hook.  Assuming
CONFIG_KEXEC_VERIFY_SIG is enabled, with commit b5ca117365d9 ("ima:
prevent kexec_load syscall based on runtime secureboot flag") we can
now block the kexec_load syscall.  Without being able to block the
kexec_load syscall, verifying the kexec image signature via the
kexec_file_load syscall is kind of pointless.

Unless you're planning on writing an LSM to prevent the kexec_load
syscall, I assume you'll want to enable integrity anyway.

Mimi