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From: James Bottomley <>
To: Mimi Zohar <>,
	Robert Holmes <>,,
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: <> (raw)
In-Reply-To: <>

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.


      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] ` <>
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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