[PATCH RFC v2 05/12] integrity: restrict INTEGRITY_KEYRING_MOK to restrict_link_by_system_trusted_or_ca

[Eric Snowberg <eric.snowberg@oracle.com>]

Set the restriction check for INTEGRITY_KEYRING_MOK keys to
restrict_link_by_system_trusted_or_ca.  This will only allow keys
into the mok keyring that are either a CA or trusted by a key contained
within the builtin or secondary trusted keyring.

Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
---
v1: Initial version
v2: Added !IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING check so mok
    keyring gets created even when it isn't enabled
---
 security/integrity/digsig.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index e07334504ef1..2f6898c89f60 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -132,7 +132,7 @@ int __init integrity_init_keyring(const unsigned int id)
 		goto out;
 	}
 
-	if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
+	if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING) && id != INTEGRITY_KEYRING_MOK)
 		return 0;
 
 	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
@@ -140,6 +140,11 @@ int __init integrity_init_keyring(const unsigned int id)
 		return -ENOMEM;
 
 	restriction->check = restrict_link_to_ima;
+	if (id == INTEGRITY_KEYRING_MOK)
+		restriction->check = restrict_link_by_system_trusted_or_ca;
+	else
+		restriction->check = restrict_link_to_ima;
+
 	perm |= KEY_USR_WRITE;
 
 out:
-- 
2.18.4