1 files changed, 18 insertions, 16 deletions

diff --git a/security/keys/key.c b/security/keys/key.c
index 01bbc6d9d19b..fdd5ca6d89fc 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -1,6 +1,6 @@
-/* key.c: basic authentication token and access key management
+/* Basic authentication token and access key management
  *
- * Copyright (C) 2004-6 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -34,7 +34,7 @@ static void key_cleanup(struct work_struct *work);
 static DECLARE_WORK(key_cleanup_task, key_cleanup);
 
 /* we serialise key instantiation and link */
-DECLARE_RWSEM(key_construction_sem);
+DEFINE_MUTEX(key_construction_mutex);
 
 /* any key who's type gets unegistered will be re-typed to this */
 static struct key_type key_type_dead = {
@@ -104,7 +104,7 @@ struct key_user *key_user_lookup(uid_t uid)
         candidate->qnkeys = 0;
         candidate->qnbytes = 0;
         spin_lock_init(&candidate->lock);
-        INIT_LIST_HEAD(&candidate->consq);
+        mutex_init(&candidate->cons_lock);
 
         rb_link_node(&candidate->node, parent, p);
         rb_insert_color(&candidate->node, &key_user_tree);
@@ -418,7 +418,7 @@ static int __key_instantiate_and_link(struct key *key,
         awaken = 0;
         ret = -EBUSY;
 
-        down_write(&key_construction_sem);
+        mutex_lock(&key_construction_mutex);
 
         /* can't instantiate twice */
         if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
@@ -443,11 +443,11 @@ static int __key_instantiate_and_link(struct key *key,
                 }
         }
 
-        up_write(&key_construction_sem);
+        mutex_unlock(&key_construction_mutex);
 
         /* wake up anyone waiting for a key to be constructed */
         if (awaken)
-                wake_up_all(&request_key_conswq);
+                wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
 
         return ret;
 
@@ -500,7 +500,7 @@ int key_negate_and_link(struct key *key,
         if (keyring)
                 down_write(&keyring->sem);
 
-        down_write(&key_construction_sem);
+        mutex_lock(&key_construction_mutex);
 
         /* can't instantiate twice */
         if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
@@ -525,14 +525,14 @@ int key_negate_and_link(struct key *key,
                         key_revoke(instkey);
         }
 
-        up_write(&key_construction_sem);
+        mutex_unlock(&key_construction_mutex);
 
         if (keyring)
                 up_write(&keyring->sem);
 
         /* wake up anyone waiting for a key to be constructed */
         if (awaken)
-                wake_up_all(&request_key_conswq);
+                wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
 
         return ret;
 
@@ -899,12 +899,14 @@ void key_revoke(struct key *key)
 {
         key_check(key);
 
-        /* make sure no one's trying to change or use the key when we mark
-         * it */
-        down_write(&key->sem);
-        set_bit(KEY_FLAG_REVOKED, &key->flags);
-
-        if (key->type->revoke)
+        /* make sure no one's trying to change or use the key when we mark it
+         * - we tell lockdep that we might nest because we might be revoking an
+         *   authorisation key whilst holding the sem on a key we've just
+         *   instantiated
+         */
+        down_write_nested(&key->sem, 1);
+        if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
+            key->type->revoke)
                 key->type->revoke(key);
 
         up_write(&key->sem);