IMA: Use the the system trusted keyrings instead of .ima_mok

Add a config option (IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY)
that, when enabled, allows keys to be added to the IMA keyrings by
userspace - with the restriction that each must be signed by a key in the
system trusted keyrings.

EPERM will be returned if this option is disabled, ENOKEY will be returned if
no authoritative key can be found and EKEYREJECTED will be returned if the
signature doesn't match.  Other errors such as ENOPKG may also be returned.

If this new option is enabled, the builtin system keyring is searched, as is
the secondary system keyring if that is also enabled.  Intermediate keys
between the builtin system keyring and the key being added can be added to
the secondary keyring (which replaces .ima_mok) to form a trust chain -
provided they are also validly signed by a key in one of the trusted keyrings.

The .ima_mok keyring is then removed and the IMA blacklist keyring gets its
own config option (IMA_BLACKLIST_KEYRING).

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 2 insertions, 11 deletions

diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 614424029de7..fbd4647767e9 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -33,28 +33,19 @@ extern int restrict_link_by_builtin_and_secondary_trusted(
 #define restrict_link_by_builtin_and_secondary_trusted restrict_link_by_builtin_trusted
 #endif
 
-#ifdef CONFIG_IMA_MOK_KEYRING
-extern struct key *ima_mok_keyring;
+#ifdef CONFIG_IMA_BLACKLIST_KEYRING
 extern struct key *ima_blacklist_keyring;
 
-static inline struct key *get_ima_mok_keyring(void)
-{
-        return ima_mok_keyring;
-}
 static inline struct key *get_ima_blacklist_keyring(void)
 {
         return ima_blacklist_keyring;
 }
 #else
-static inline struct key *get_ima_mok_keyring(void)
-{
-        return NULL;
-}
 static inline struct key *get_ima_blacklist_keyring(void)
 {
         return NULL;
 }
-#endif /* CONFIG_IMA_MOK_KEYRING */
+#endif /* CONFIG_IMA_BLACKLIST_KEYRING */
 
 
 #endif /* _KEYS_SYSTEM_KEYRING_H */