[PATCH] keys: discard the contents of a key on revocation
[linux-2.6.git] / security / keys / keyring.c
index 6c282bd937e26763c33f9a05b68817eb1d1af8a4..e8d02acc51e7180f23a31b849ccce820418fd55c 100644 (file)
@@ -49,6 +49,7 @@ static inline unsigned keyring_hash(const char *desc)
 static int keyring_instantiate(struct key *keyring,
                               const void *data, size_t datalen);
 static int keyring_match(const struct key *keyring, const void *criterion);
+static void keyring_revoke(struct key *keyring);
 static void keyring_destroy(struct key *keyring);
 static void keyring_describe(const struct key *keyring, struct seq_file *m);
 static long keyring_read(const struct key *keyring,
@@ -59,6 +60,7 @@ struct key_type key_type_keyring = {
        .def_datalen    = sizeof(struct keyring_list),
        .instantiate    = keyring_instantiate,
        .match          = keyring_match,
+       .revoke         = keyring_revoke,
        .destroy        = keyring_destroy,
        .describe       = keyring_describe,
        .read           = keyring_read,
@@ -953,3 +955,22 @@ int keyring_clear(struct key *keyring)
 } /* end keyring_clear() */
 
 EXPORT_SYMBOL(keyring_clear);
+
+/*****************************************************************************/
+/*
+ * dispose of the links from a revoked keyring
+ * - called with the key sem write-locked
+ */
+static void keyring_revoke(struct key *keyring)
+{
+       struct keyring_list *klist = keyring->payload.subscriptions;
+
+       /* adjust the quota */
+       key_payload_reserve(keyring, 0);
+
+       if (klist) {
+               rcu_assign_pointer(keyring->payload.subscriptions, NULL);
+               call_rcu(&klist->rcu, keyring_clear_rcu_disposal);
+       }
+
+} /* end keyring_revoke() */