KEYS: validate certificate trust only with selected 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 further restricts the certificates to those signed by a
particular key on the system keyring.

This patch defines a new kernel parameter 'ca_keys' to identify the
specific key which must be used for trust validation of certificates.

Simplified Mimi's "KEYS: define an owner trusted keyring" patch.

Changelog:
- support for builtin x509 public keys only
- export "asymmetric_keyid_match"
- remove ifndefs MODULE
- rename kernel boot parameter from keys_ownerid to ca_keys

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8b2ab548b6e4..bdb193afe176 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -566,6 +566,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         possible to determine what the correct size should be.
                         This option provides an override for these situations.
 
+        ca_keys=        [KEYS] This parameter identifies a specific key(s) on
+                        the system trusted keyring to be used for certificate
+                        trust validation.
+                        format: id:<keyid>
+
         ccw_timeout_log [S390]
                         See Documentation/s390/CommonIO for details.