[PATCH] keys: restrict contents of /proc/keys to Viewable keys

[safe/jmp/linux-2.6] / security / keys / user_defined.c

diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index cbda3b2..5bbfdeb 100644 (file)
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -26,9 +26,9 @@
 struct key_type key_type_user = {
        .name           = "user",
        .instantiate    = user_instantiate,
-       .duplicate      = user_duplicate,
        .update         = user_update,
        .match          = user_match,
+       .revoke         = user_revoke,
        .destroy        = user_destroy,
        .describe       = user_describe,
        .read           = user_read,
@@ -73,37 +73,6 @@ EXPORT_SYMBOL_GPL(user_instantiate);
 
 /*****************************************************************************/
 /*
- * duplicate a user defined key
- * - both keys' semaphores are locked against further modification
- * - the new key cannot yet be accessed
- */
-int user_duplicate(struct key *key, const struct key *source)
-{
-       struct user_key_payload *upayload, *spayload;
-       int ret;
-
-       /* just copy the payload */
-       ret = -ENOMEM;
-       upayload = kmalloc(sizeof(*upayload) + source->datalen, GFP_KERNEL);
-       if (upayload) {
-               spayload = rcu_dereference(source->payload.data);
-               BUG_ON(source->datalen != spayload->datalen);
-
-               upayload->datalen = key->datalen = spayload->datalen;
-               memcpy(upayload->data, spayload->data, key->datalen);
-
-               key->payload.data = upayload;
-               ret = 0;
-       }
-
-       return ret;
-
-} /* end user_duplicate() */
-
-EXPORT_SYMBOL_GPL(user_duplicate);
-
-/*****************************************************************************/
-/*
  * dispose of the old data from an updated user defined key
  */
 static void user_update_rcu_disposal(struct rcu_head *rcu)
@@ -174,7 +143,28 @@ EXPORT_SYMBOL_GPL(user_match);
 
 /*****************************************************************************/
 /*
- * dispose of the data dangling from the corpse of a user
+ * dispose of the links from a revoked keyring
+ * - called with the key sem write-locked
+ */
+void user_revoke(struct key *key)
+{
+       struct user_key_payload *upayload = key->payload.data;
+
+       /* clear the quota */
+       key_payload_reserve(key, 0);
+
+       if (upayload) {
+               rcu_assign_pointer(key->payload.data, NULL);
+               call_rcu(&upayload->rcu, user_update_rcu_disposal);
+       }
+
+} /* end user_revoke() */
+
+EXPORT_SYMBOL(user_revoke);
+
+/*****************************************************************************/
+/*
+ * dispose of the data dangling from the corpse of a user key
  */
 void user_destroy(struct key *key)
 {