Re: [RFC PATCH 03/20] X.509: Allow X.509 certs to be blacklisted [ver #2]

From: Mimi Zohar
Date: Wed Jan 20 2016 - 15:37:44 EST

On Tue, 2016-01-19 at 11:30 +0000, David Howells wrote:
> Allow X.509 certs to be blacklisted based on their TBS hash.

What is the TBS hash? This doesn't seem to be the key identifier. The
cert associated with this key identifier is loaded onto the .ima

eg: openssl x509 -in <pathname> -inform DER -notext -out


X509v3 extensions:
X509v3 Subject Key Identifier:


# keyctl show %keyring:.blacklist
466574863 ---lswrv 0 0 keyring: .blacklist
433453563 ---lswrv 0 0 \_ blacklist:


> This is
> convenient since we have to determine this anyway to be able to check the
> signature on an X.509 certificate.
> If a certificate built into the kernel is blacklisted, something like the
> following might then be seen during boot:
> X.509: Cert 123412341234c55c1dcc601ab8e172917706aa32fb5eaf826813547fdf02dd46 is blacklisted
> Problem loading in-kernel X.509 certificate (-129)
> where the hex string shown is the blacklisted hash.
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>