KEYS: validate certificate trust with selected owner or builtin key

Instead of allowing public keys, with certificates signed by any key on the system trusted keyring, to be added to a trusted keyring, this patch set further restricts the certificates to those signed by a particular key or builtin keys on the system keyring.

This patch defines a new kernel parameter 'keys_ownerid={id: | builtin}' to use specific key or any builtin key.

Changes to v1:
* key id matching code from asymmetric_type.c is reused in the patch

Thanks,
Dmitry

Dmitry Kasatkin (3):
KEYS: make key id matching as a dedicated function
KEYS: validate certificate trust only with selected owner key
KEYS: validate certificate trust only with builtin keys

 Documentation/kernel-parameters.txt      |  5 ++++
 crypto/asymmetric_keys/asymmetric_keys.h |  2 ++
 crypto/asymmetric_keys/asymmetric_type.c | 50 ++++++++++++++++++++------------
 crypto/asymmetric_keys/x509_public_key.c | 26 +++++++++++++++--
 include/linux/key.h                      |  1 +
 kernel/system_keyring.c                  |  1 +
 6 files changed, 64 insertions(+), 21 deletions(-)

1.9.1