KEYS: keyring_serialise_link_sem is only needed for keyring->keyring links
keyring_serialise_link_sem is only needed for keyring->keyring links as it's
used to prevent cycle detection from being avoided by parallel keyring
additions.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 2fb2bc9..29de5ee 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -705,13 +705,14 @@
if (keyring->type != &key_type_keyring)
goto error;
- /* serialise link/link calls to prevent parallel calls causing a
- * cycle when applied to two keyring in opposite orders */
- down_write(&keyring_serialise_link_sem);
-
- /* check that we aren't going to create a cycle adding one keyring to
- * another */
+ /* do some special keyring->keyring link checks */
if (key->type == &key_type_keyring) {
+ /* serialise link/link calls to prevent parallel calls causing
+ * a cycle when applied to two keyring in opposite orders */
+ down_write(&keyring_serialise_link_sem);
+
+ /* check that we aren't going to create a cycle adding one
+ * keyring to another */
ret = keyring_detect_cycle(keyring, key);
if (ret < 0)
goto error2;
@@ -814,7 +815,8 @@
done:
ret = 0;
error2:
- up_write(&keyring_serialise_link_sem);
+ if (key->type == &key_type_keyring)
+ up_write(&keyring_serialise_link_sem);
error:
return ret;