Set the restriction check for INTEGRITY_KEYRING_MACHINE keys to
restrict_link_by_ca.  This will only allow CA keys into the machine
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
v3: Rename restrict_link_by_system_trusted_or_ca to restrict_link_by_ca
v4: removed unnecessary restriction->check set
v5: Rename to machine keyring
v6: split line over 80 char (suggested by Mimi)
v8: Unmodified from v6
---
 security/integrity/digsig.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 910fe29a5037..e7dfc55a7c55 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c

@@ -132,14 +132,18 @@ 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_MACHINE)
 		return 0;
 
 	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
 	if (!restriction)
 		return -ENOMEM;
 
-	restriction->check = restrict_link_to_ima;
+	if (id == INTEGRITY_KEYRING_MACHINE)
+		restriction->check = restrict_link_by_ca;
+	else
+		restriction->check = restrict_link_to_ima;
 
 	/*
 	 * No additional keys shall be allowed to load into the machine

-- 
2.18.4