From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Mimi Zohar <zohar@linux.ibm.com>,
Robert Holmes <robeholmes@gmail.com>,
jeyu@kernel.org, linux-kernel@vger.kernel.org
Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v2] KEYS: Make use of platform keyring for module signature verify
Date: Thu, 25 Apr 2019 12:46:45 -0700 [thread overview]
Message-ID: <1556221605.24945.3.camel@HansenPartnership.com> (raw)
In-Reply-To: <1556193350.3894.92.camel@linux.ibm.com>
On Thu, 2019-04-25 at 07:55 -0400, Mimi Zohar wrote:
> On Wed, 2019-04-24 at 14:33 +0000, Robert Holmes wrote:
> > This patch completes commit 278311e417be ("kexec, KEYS: Make use of
> > platform keyring for signature verify") which, while adding the
> > platform keyring for bzImage verification, neglected to also add
> > this keyring for module verification.
> >
> > As such, kernel modules signed with keys from the MokList variable
> > were not successfully verified.
>
> Using the platform keyring keys for verifying kernel modules was not
> neglected, but rather intentional. This patch description should
> clearly explain the reason for needing to verify kernel module
> signatures based on the pre-boot keys. (Hint: verifying kernel
> modules based on the pre-boot keys was previously rejected.)
To clarify here: most Linux systems use shim/mok to pivot the root of
trust away from the Secure Boot db variable to the new MokList/shim
built in keys. This makes the actual secure boot db outside the
expected Linux Kernel trust boundary *unless* the user has taken
ownership of the system and is actually using db for their own trusted
keys. This makes the policy for what pre-boot keys to trust within the
Linux boundary very complex, which is why we default to not using the
pre-boot keys at all.
James
prev parent reply other threads:[~2019-04-25 19:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-24 14:33 [PATCH v2] KEYS: Make use of platform keyring for module signature verify Robert Holmes
[not found] ` <20190424160609.EE5ED21901@mail.kernel.org>
2019-04-24 17:36 ` Robert Holmes
2019-04-25 11:55 ` Mimi Zohar
2019-04-25 18:21 ` Jeremy Cline
2019-04-25 19:46 ` James Bottomley [this message]
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