This code allows us to parse:
- X.509 certificates: at least enough to verify the signatures on the PKCS#7
messages. We expect that the certificates embedded in GRUB will be leaf
certificates, not CA certificates. The parser enforces this.
- X.509 certificates support the Extended Key Usage extension and handle it by
verifying that the certificate has a Code Signing usage.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> # EKU support
Reported-by: Michal Suchanek <msuchanek@suse.com> # key usage issue
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Reviewed-by: Avnish Chouhan <avnish@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
