KEYS: Split role of the keyring pointer for keyring restrict functions

The first argument to the restrict_link_func_t functions was a keyring
pointer. These functions are called by the key subsystem with this
argument set to the destination keyring, but restrict_link_by_signature
expects a pointer to the relevant trusted keyring.

Restrict functions may need something other than a single struct key
pointer to allow or reject key linkage, so the data used to make that
decision (such as the trust keyring) is moved to a new, fourth
argument. The first argument is now always the destination keyring.

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>

1 files changed, 11 insertions, 7 deletions

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 50979d6dcecd..e39cce68dcfa 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -32,11 +32,13 @@ extern __initconst const unsigned long system_certificate_list_size;
  * Restrict the addition of keys into a keyring based on the key-to-be-added
  * being vouched for by a key in the built in system keyring.
  */
-int restrict_link_by_builtin_trusted(struct key *keyring,
+int restrict_link_by_builtin_trusted(struct key *dest_keyring,
                                      const struct key_type *type,
-                                     const union key_payload *payload)
+                                     const union key_payload *payload,
+                                     struct key *restriction_key)
 {
-        return restrict_link_by_signature(builtin_trusted_keys, type, payload);
+        return restrict_link_by_signature(dest_keyring, type, payload,
+                                          builtin_trusted_keys);
 }
 
 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
@@ -49,20 +51,22 @@ int restrict_link_by_builtin_trusted(struct key *keyring,
  * keyrings.
  */
 int restrict_link_by_builtin_and_secondary_trusted(
-        struct key *keyring,
+        struct key *dest_keyring,
         const struct key_type *type,
-        const union key_payload *payload)
+        const union key_payload *payload,
+        struct key *restrict_key)
 {
         /* If we have a secondary trusted keyring, then that contains a link
          * through to the builtin keyring and the search will follow that link.
          */
         if (type == &key_type_keyring &&
-            keyring == secondary_trusted_keys &&
+            dest_keyring == secondary_trusted_keys &&
             payload == &builtin_trusted_keys->payload)
                 /* Allow the builtin keyring to be added to the secondary */
                 return 0;
 
-        return restrict_link_by_signature(secondary_trusted_keys, type, payload);
+        return restrict_link_by_signature(dest_keyring, type, payload,
+                                          secondary_trusted_keys);
 }
 #endif