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authorDavid Howells <dhowells@redhat.com>2010-04-30 14:32:28 +0100
committerJames Morris <jmorris@namei.org>2010-05-06 10:56:52 +1000
commit553d603c8fce8cf727eb26e4bf6b9549cd4623f1 (patch)
tree137d9976ac663371d5f4f9ccf59ef4fb1ea9bc88
parent0ffbe2699cda6afbe08501098dff8a8c2fe6ae09 (diff)
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>
-rw-r--r--security/keys/keyring.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 2fb2bc9712ae..29de5ee3457b 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -705,13 +705,14 @@ int __key_link(struct key *keyring, struct key *key)
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 @@ int __key_link(struct key *keyring, struct key *key)
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;