From: David Howells <dhowells@redhat.com>
To: Eric Snowberg <eric.snowberg@oracle.com>
Cc: dhowells@redhat.com, dwmw2@infradead.org,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
herbert@gondor.apana.org.au, davem@davemloft.net,
jmorris@namei.org, serge@hallyn.com, nayna@linux.ibm.com,
Mimi Zohar <zohar@linux.ibm.com>,
erichte@linux.ibm.com, mpe@ellerman.id.au,
keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-crypto@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH v4] certs: Add EFI_CERT_X509_GUID support for dbx entries
Date: Tue, 12 Jan 2021 14:57:39 +0000 [thread overview]
Message-ID: <2442460.1610463459@warthog.procyon.org.uk> (raw)
In-Reply-To: <E090372C-06A3-4991-8FC3-F06A0DA60729@oracle.com>
Eric Snowberg <eric.snowberg@oracle.com> wrote:
> > On Dec 10, 2020, at 2:49 AM, David Howells <dhowells@redhat.com> wrote:
> >
> > Eric Snowberg <eric.snowberg@oracle.com> wrote:
> >
> >> Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID
> >> is found, it is added as an asymmetrical key to the .blacklist keyring.
> >> Anytime the .platform keyring is used, the keys in the .blacklist keyring
> >> are referenced, if a matching key is found, the key will be rejected.
> >
> > Ummm... Why this way and not as a blacklist key which takes up less space?
> > I'm guessing that you're using the key chain matching logic. We really only
> > need to blacklist the key IDs.
>
> I implemented it this way so that certs in the dbx would only impact
> the .platform keyring. I was under the impression we didn’t want to have
> Secure Boot UEFI db/dbx certs dictate keyring functionality within the kernel
> itself. Meaning if we have a matching dbx cert in any other keyring (builtin,
> secondary, ima, etc.), it would be allowed. If that is not how you’d like to
> see it done, let me know and I’ll make the change.
I wonder if that is that the right thing to do. I guess this is a policy
decision and may depend on the particular user.
> > Also, what should happen if a revocation cert rejected by the blacklist?
>
> I’m not sure I understand the question. How would it be rejected?
The SHA256 of a revocation cert being loaded could match an
already-blacklisted SHA256 sum, either compiled in or already loaded from
UEFI.
David
next prev parent reply other threads:[~2021-01-12 14:59 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-16 0:49 [PATCH v4] certs: Add EFI_CERT_X509_GUID support for dbx entries Eric Snowberg
2020-09-16 18:09 ` Jarkko Sakkinen
2020-12-10 9:49 ` David Howells
2020-12-10 18:56 ` Eric Snowberg
2021-01-12 14:57 ` David Howells [this message]
2021-01-13 20:41 ` Jarkko Sakkinen
2021-01-14 0:11 ` Eric Snowberg
2021-01-15 9:15 ` Jarkko Sakkinen
2021-01-15 16:49 ` Eric Snowberg
2021-01-20 11:26 ` Jarkko Sakkinen
2021-01-20 22:13 ` Eric Snowberg
2021-01-21 0:36 ` Jarkko Sakkinen
2021-01-27 11:46 ` David Howells
2021-01-27 14:03 ` Mimi Zohar
2021-01-27 15:41 ` Eric Snowberg
2021-01-28 4:13 ` Nayna
2021-01-30 10:24 ` Jarkko Sakkinen
2021-01-29 23:27 ` Jarkko Sakkinen
2021-01-12 17:10 ` David Howells
2021-01-12 19:13 ` Eric Snowberg
2021-01-15 17:21 ` James Bottomley
2021-01-15 23:01 ` Eric Snowberg
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