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From: Eric Snowberg <eric.snowberg@oracle.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Mimi Zohar <zohar@linux.ibm.com>,
	keyrings@vger.kernel.org,
	linux-integrity <linux-integrity@vger.kernel.org>,
	David Howells <dhowells@redhat.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S . Miller" <davem@davemloft.net>,
	James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	keescook@chromium.org, gregkh@linuxfoundation.org,
	torvalds@linux-foundation.org, scott.branden@broadcom.com,
	weiyongjun1@huawei.com, nayna@linux.ibm.com, ebiggers@google.com,
	ardb@kernel.org,
	Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
	lszubowi@redhat.com, linux-kernel@vger.kernel.org,
	linux-crypto@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	pjones@redhat.com,
	"konrad.wilk@oracle.com" <konrad.wilk@oracle.com>,
	Patrick Uiterwijk <patrick@puiterwijk.org>
Subject: Re: [PATCH v4 00/12] Enroll kernel keys thru MOK
Date: Mon, 23 Aug 2021 11:48:11 -0600	[thread overview]
Message-ID: <D6D0C236-38C9-40EF-AABE-41F90CA796C8@oracle.com> (raw)
In-Reply-To: <335ba50bcb9069faac135bce77c6f7ba19bd90ca.camel@kernel.org>


> On Aug 23, 2021, at 11:35 AM, Jarkko Sakkinen <jarkko@kernel.org> wrote:
> 
> On Thu, 2021-08-19 at 09:10 -0400, Mimi Zohar wrote:
>> On Thu, 2021-08-19 at 14:38 +0300, Jarkko Sakkinen wrote:
>>> On Wed, 2021-08-18 at 20:20 -0400, Eric Snowberg wrote:
>>>> Many UEFI Linux distributions boot using shim.  The UEFI shim provides
>>>> what is called Machine Owner Keys (MOK).  Shim uses both the UEFI Secure
>>>> Boot DB and MOK keys to validate the next step in the boot chain.  The
>>>> MOK facility can be used to import user generated keys.  These keys can
>>>> be used to sign an end-user development kernel build.  When Linux boots,
>>>> pre-boot keys (both UEFI Secure Boot DB and MOK keys) get loaded in the
>>>> Linux .platform keyring.  
>>>> 
>>>> Currently, pre-boot keys are not trusted within the Linux trust boundary
>>>> [1]. These platform keys can only be used for kexec. If an end-user
>>>> wants to use their own key within the Linux trust boundary, they must
>>>> either compile it into the kernel themselves or use the insert-sys-cert
>>>> script. Both options present a problem. Many end-users do not want to
>>>> compile their own kernels. With the insert-sys-cert option, there are
>>>> missing upstream changes [2].  Also, with the insert-sys-cert option,
>>>> the end-user must re-sign their kernel again with their own key, and
>>>> then insert that key into the MOK db. Another problem with
>>>> insert-sys-cert is that only a single key can be inserted into a
>>>> compressed kernel.
>>>> 
>>>> Having the ability to insert a key into the Linux trust boundary opens
>>>> up various possibilities.  The end-user can use a pre-built kernel and
>>>> sign their own kernel modules.  It also opens up the ability for an
>>>> end-user to more easily use digital signature based IMA-appraisal.  To
>>>> get a key into the ima keyring, it must be signed by a key within the
>>>> Linux trust boundary.
>>> 
>>> As of today, I can use a prebuilt kernel, crate my own MOK key and sign
>>> modules. What will be different?
>> 
>> The UEFI db and MOK keys are being loaded onto the .platform keyring,
>> which is suppose to be limited to verifying the kexec kernel image
>> signature.  With a downstream patch, kernel modules are being verified
>> as well.
>> 
>> Initially Patrick Uiterwijk's "[PATCH 0/3] Load keys from TPM2 NV Index
>> on IMA keyring" patch set attempted to define a new root of trust based
>> on a key stored in the TPM.  This patch set is similarly attempting to
>> define a new root of trust based on CA keys stored in the MOK db.
>> 
>> The purpose of this patch set is to define a new, safe trust source
>> parallel to the builtin keyring, without relying on a downstream patch.
>> With the new root of trust, the end user could sign his own kernel
>> modules, sign third party keys, and load keys onto the IMA keyring,
>> which can be used for signing the IMA policy and other files.
> 
> I can, as of today, generate my own mok key and sign my LKM's, and
> kernel will verify my LKM's.
> 
> What is different?

Are you sure your kernel doesn’t contain some version of the rejected 
patch referenced in the cover letter  [1]?

https://lore.kernel.org/lkml/1556221605.24945.3.camel@HansenPartnership.com/


      reply	other threads:[~2021-08-23 17:49 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19  0:20 Eric Snowberg
2021-08-19  0:20 ` [PATCH v4 01/12] integrity: Introduce a Linux keyring for the Machine Owner Key (MOK) Eric Snowberg
2021-08-19  0:20 ` [PATCH v4 02/12] integrity: Do not allow mok keyring updates following init Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 03/12] KEYS: CA link restriction Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 04/12] integrity: restrict INTEGRITY_KEYRING_MOK to restrict_link_by_ca Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 05/12] integrity: add new keyring handler for mok keys Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 06/12] KEYS: add a reference to mok keyring Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 07/12] KEYS: Introduce link restriction to include builtin, secondary and mok keys Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 08/12] KEYS: integrity: change link restriction to trust the mok keyring Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 09/12] KEYS: link secondary_trusted_keys to mok trusted keys Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 10/12] integrity: store reference to mok keyring Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 11/12] integrity: Trust MOK keys if MokListTrustedRT found Eric Snowberg
2021-08-19  0:21 ` [PATCH v4 12/12] integrity: Only use mok keyring when uefi_check_trust_mok_keys is true Eric Snowberg
2021-08-19 11:38 ` [PATCH v4 00/12] Enroll kernel keys thru MOK Jarkko Sakkinen
2021-08-19 13:10   ` Mimi Zohar
2021-08-19 15:23     ` Eric Snowberg
2021-08-19 17:32       ` Mimi Zohar
2021-08-23 17:51         ` Jarkko Sakkinen
2021-08-23 20:48           ` Nayna
2021-08-24 14:34             ` Mimi Zohar
2021-08-25 22:21               ` Jarkko Sakkinen
2021-08-25 22:27                 ` James Bottomley
2021-08-27 20:44                   ` Nayna
2021-08-30 17:39                     ` Eric Snowberg
2021-09-01  0:52                       ` Nayna
2021-09-01  1:51                         ` Eric Snowberg
2021-09-02 10:18                           ` Mimi Zohar
2021-09-01  4:34                     ` Jarkko Sakkinen
2021-09-01  4:36                       ` Jarkko Sakkinen
2021-09-01  4:46                         ` Jarkko Sakkinen
2021-08-23 17:37       ` Jarkko Sakkinen
2021-08-23 17:35     ` Jarkko Sakkinen
2021-08-23 17:48       ` Eric Snowberg [this message]

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