Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6

[sfrench/cifs-2.6.git] / security / keys / key.c

diff --git a/security/keys/key.c b/security/keys/key.c
index ac9326c5f1da3f1e1781d8654ac816bb83355560..654d23baf3525ceee6134f75039a4d450fc1edd9 100644 (file)
--- 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);
@@ -188,6 +188,7 @@ static inline void key_alloc_serial(struct key *key)
 
        spin_lock(&key_serial_lock);
 
+attempt_insertion:
        parent = NULL;
        p = &key_serial_tree.rb_node;
 
@@ -202,39 +203,33 @@ static inline void key_alloc_serial(struct key *key)
                else
                        goto serial_exists;
        }
-       goto insert_here;
+
+       /* we've found a suitable hole - arrange for this key to occupy it */
+       rb_link_node(&key->serial_node, parent, p);
+       rb_insert_color(&key->serial_node, &key_serial_tree);
+
+       spin_unlock(&key_serial_lock);
+       return;
 
        /* we found a key with the proposed serial number - walk the tree from
         * that point looking for the next unused serial number */
 serial_exists:
        for (;;) {
                key->serial++;
-               if (key->serial < 2)
-                       key->serial = 2;
-
-               if (!rb_parent(parent))
-                       p = &key_serial_tree.rb_node;
-               else if (rb_parent(parent)->rb_left == parent)
-                       p = &(rb_parent(parent)->rb_left);
-               else
-                       p = &(rb_parent(parent)->rb_right);
+               if (key->serial < 3) {
+                       key->serial = 3;
+                       goto attempt_insertion;
+               }
 
                parent = rb_next(parent);
                if (!parent)
-                       break;
+                       goto attempt_insertion;
 
                xkey = rb_entry(parent, struct key, serial_node);
                if (key->serial < xkey->serial)
-                       goto insert_here;
+                       goto attempt_insertion;
        }
 
-       /* we've found a suitable hole - arrange for this key to occupy it */
-insert_here:
-       rb_link_node(&key->serial_node, parent, p);
-       rb_insert_color(&key->serial_node, &key_serial_tree);
-
-       spin_unlock(&key_serial_lock);
-
 } /* end key_alloc_serial() */
 
 /*****************************************************************************/
@@ -423,7 +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)) {
@@ -448,11 +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;
 
@@ -505,7 +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)) {
@@ -530,14 +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;
 
@@ -825,7 +820,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
        key = key_alloc(ktype, description, current->fsuid, current->fsgid,
                        current, perm, flags);
        if (IS_ERR(key)) {
-               key_ref = ERR_PTR(PTR_ERR(key));
+               key_ref = ERR_CAST(key);
                goto error_3;
        }
 
@@ -904,12 +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);
@@ -1006,7 +1003,7 @@ void __init key_init(void)
 {
        /* allocate a slab in which we can store keys */
        key_jar = kmem_cache_create("key_jar", sizeof(struct key),
-                       0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+                       0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
 
        /* add the special key types */
        list_add_tail(&key_type_keyring.link, &key_types_list);