[PATCH] Keys: Remove key duplication

Remove the key duplication stuff since there's nothing that uses it, no way
to get at it and it's awkward to deal with for LSM purposes.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

6 files changed, 3 insertions, 177 deletions

diff --git a/Documentation/keys.txt b/Documentation/keys.txt
index 31154882000a..6304db59bfe4 100644
--- a/Documentation/keys.txt
+++ b/Documentation/keys.txt
@@ -860,24 +860,6 @@ The structure has a number of fields, some of which are mandatory:
      It is safe to sleep in this method.
 
 
- (*) int (*duplicate)(struct key *key, const struct key *source);
-
-     If this type of key can be duplicated, then this method should be
-     provided. It is called to copy the payload attached to the source into the
-     new key. The data length on the new key will have been updated and the
-     quota adjusted already.
-
-     This method will be called with the source key's semaphore read-locked to
-     prevent its payload from being changed, thus RCU constraints need not be
-     applied to the source key.
-
-     This method does not have to lock the destination key in order to attach a
-     payload. The fact that KEY_FLAG_INSTANTIATED is not set in key->flags
-     prevents anything else from gaining access to the key.
-
-     It is safe to sleep in this method.
-
-
  (*) int (*update)(struct key *key, const void *data, size_t datalen);
 
      If this type of key can be updated, then this method should be provided.
diff --git a/include/keys/user-type.h b/include/keys/user-type.h
index 26f6ec38577a..a3dae1803f45 100644
--- a/include/keys/user-type.h
+++ b/include/keys/user-type.h
@@ -35,7 +35,6 @@ struct user_key_payload {
 extern struct key_type key_type_user;
 
 extern int user_instantiate(struct key *key, const void *data, size_t datalen);
-extern int user_duplicate(struct key *key, const struct key *source);
 extern int user_update(struct key *key, const void *data, size_t datalen);
 extern int user_match(const struct key *key, const void *criterion);
 extern void user_destroy(struct key *key);
diff --git a/include/linux/key.h b/include/linux/key.h
index 53513a3be53b..4d189e51bc6c 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -193,14 +193,6 @@ struct key_type {
          */
         int (*instantiate)(struct key *key, const void *data, size_t datalen);
 
-        /* duplicate a key of this type (optional)
-         * - the source key will be locked against change
-         * - the new description will be attached
-         * - the quota will have been adjusted automatically from
-         *   source->quotalen
-         */
-        int (*duplicate)(struct key *key, const struct key *source);
-
         /* update a key of this type (optional)
          * - this method should call key_payload_reserve() to recalculate the
          *   quota consumption
diff --git a/security/keys/key.c b/security/keys/key.c
index 01bcfecb7eae..bb036623d0a8 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -240,9 +240,9 @@ static inline void key_alloc_serial(struct key *key)
 /*
  * allocate a key of the specified type
  * - update the user's quota to reflect the existence of the key
- * - called from a key-type operation with key_types_sem read-locked by either
- *   key_create_or_update() or by key_duplicate(); this prevents unregistration
- *   of the key type
+ * - called from a key-type operation with key_types_sem read-locked by
+ *   key_create_or_update()
+ *   - this prevents unregistration of the key type
  * - upon return the key is as yet uninstantiated; the caller needs to either
  *   instantiate the key or discard it before returning
  */
@@ -889,56 +889,6 @@ EXPORT_SYMBOL(key_update);
 
 /*****************************************************************************/
 /*
- * duplicate a key, potentially with a revised description
- * - must be supported by the keytype (keyrings for instance can be duplicated)
- */
-struct key *key_duplicate(struct key *source, const char *desc)
-{
-        struct key *key;
-        int ret;
-
-        key_check(source);
-
-        if (!desc)
-                desc = source->description;
-
-        down_read(&key_types_sem);
-
-        ret = -EINVAL;
-        if (!source->type->duplicate)
-                goto error;
-
-        /* allocate and instantiate a key */
-        key = key_alloc(source->type, desc, current->fsuid, current->fsgid,
-                        source->perm, 0);
-        if (IS_ERR(key))
-                goto error_k;
-
-        down_read(&source->sem);
-        ret = key->type->duplicate(key, source);
-        up_read(&source->sem);
-        if (ret < 0)
-                goto error2;
-
-        atomic_inc(&key->user->nikeys);
-        set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
-
- error_k:
-        up_read(&key_types_sem);
- out:
-        return key;
-
- error2:
-        key_put(key);
- error:
-        up_read(&key_types_sem);
-        key = ERR_PTR(ret);
-        goto out;
-
-} /* end key_duplicate() */
-
-/*****************************************************************************/
-/*
  * revoke a key
  */
 void key_revoke(struct key *key)
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 4e9fa8be44b8..0acecbd4fa37 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -48,7 +48,6 @@ static inline unsigned keyring_hash(const char *desc)
  */
 static int keyring_instantiate(struct key *keyring,
                                const void *data, size_t datalen);
-static int keyring_duplicate(struct key *keyring, const struct key *source);
 static int keyring_match(const struct key *keyring, const void *criterion);
 static void keyring_destroy(struct key *keyring);
 static void keyring_describe(const struct key *keyring, struct seq_file *m);
@@ -59,7 +58,6 @@ struct key_type key_type_keyring = {
         .name           = "keyring",
         .def_datalen    = sizeof(struct keyring_list),
         .instantiate    = keyring_instantiate,
-        .duplicate      = keyring_duplicate,
         .match          = keyring_match,
         .destroy        = keyring_destroy,
         .describe       = keyring_describe,
@@ -120,68 +118,6 @@ static int keyring_instantiate(struct key *keyring,
 
 /*****************************************************************************/
 /*
- * duplicate the list of subscribed keys from a source keyring into this one
- */
-static int keyring_duplicate(struct key *keyring, const struct key *source)
-{
-        struct keyring_list *sklist, *klist;
-        unsigned max;
-        size_t size;
-        int loop, ret;
-
-        const unsigned limit =
-                (PAGE_SIZE - sizeof(*klist)) / sizeof(struct key *);
-
-        ret = 0;
-
-        /* find out how many keys are currently linked */
-        rcu_read_lock();
-        sklist = rcu_dereference(source->payload.subscriptions);
-        max = 0;
-        if (sklist)
-                max = sklist->nkeys;
-        rcu_read_unlock();
-
-        /* allocate a new payload and stuff load with key links */
-        if (max > 0) {
-                BUG_ON(max > limit);
-
-                max = (max + 3) & ~3;
-                if (max > limit)
-                        max = limit;
-
-                ret = -ENOMEM;
-                size = sizeof(*klist) + sizeof(struct key *) * max;
-                klist = kmalloc(size, GFP_KERNEL);
-                if (!klist)
-                        goto error;
-
-                /* set links */
-                rcu_read_lock();
-                sklist = rcu_dereference(source->payload.subscriptions);
-
-                klist->maxkeys = max;
-                klist->nkeys = sklist->nkeys;
-                memcpy(klist->keys,
-                       sklist->keys,
-                       sklist->nkeys * sizeof(struct key *));
-
-                for (loop = klist->nkeys - 1; loop >= 0; loop--)
-                        atomic_inc(&klist->keys[loop]->usage);
-
-                rcu_read_unlock();
-
-                rcu_assign_pointer(keyring->payload.subscriptions, klist);
-                ret = 0;
-        }
-
- error:
-        return ret;
-
-} /* end keyring_duplicate() */
-
-/*****************************************************************************/
-/*
  * match keyrings on their name
  */
 static int keyring_match(const struct key *keyring, const void *description)
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index cbda3b2780a1..8e71895b97a7 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -26,7 +26,6 @@
 struct key_type key_type_user = {
         .name           = "user",
         .instantiate    = user_instantiate,
-        .duplicate      = user_duplicate,
         .update         = user_update,
         .match          = user_match,
         .destroy        = user_destroy,
@@ -68,42 +67,10 @@ error:
         return ret;
 
 } /* end user_instantiate() */
-
 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)