[PATCH] Fix function/macro name collision on i386 oprofile

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

diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 8d65b3a281297e60e09bccb4724092b31406dd7a..e446acba73d325a1d222a0a130c7f23f6a4232a9 100644 (file)
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -42,12 +42,21 @@ struct key_type key_type_user = {
        .read           = user_read,
 };
 
+struct user_key_payload {
+       struct rcu_head rcu;            /* RCU destructor */
+       unsigned short  datalen;        /* length of this data */
+       char            data[0];        /* actual data */
+};
+
+EXPORT_SYMBOL_GPL(key_type_user);
+
 /*****************************************************************************/
 /*
  * instantiate a user defined key
  */
 static int user_instantiate(struct key *key, const void *data, size_t datalen)
 {
+       struct user_key_payload *upayload;
        int ret;
 
        ret = -EINVAL;
@@ -58,13 +67,15 @@ static int user_instantiate(struct key *key, const void *data, size_t datalen)
        if (ret < 0)
                goto error;
 
-       /* attach the data */
        ret = -ENOMEM;
-       key->payload.data = kmalloc(datalen, GFP_KERNEL);
-       if (!key->payload.data)
+       upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+       if (!upayload)
                goto error;
 
-       memcpy(key->payload.data, data, datalen);
+       /* attach the data */
+       upayload->datalen = datalen;
+       memcpy(upayload->data, data, datalen);
+       rcu_assign_pointer(key->payload.data, upayload);
        ret = 0;
 
  error:
@@ -75,18 +86,25 @@ static int user_instantiate(struct key *key, const void *data, size_t datalen)
 /*****************************************************************************/
 /*
  * duplicate a user defined key
+ * - both keys' semaphores are locked against further modification
+ * - the new key cannot yet be accessed
  */
 static int user_duplicate(struct key *key, const struct key *source)
 {
+       struct user_key_payload *upayload, *spayload;
        int ret;
 
        /* just copy the payload */
        ret = -ENOMEM;
-       key->payload.data = kmalloc(source->datalen, GFP_KERNEL);
+       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);
 
-       if (key->payload.data) {
-               key->datalen = source->datalen;
-               memcpy(key->payload.data, source->payload.data, source->datalen);
+               key->payload.data = upayload;
                ret = 0;
        }
 
@@ -94,42 +112,56 @@ static int user_duplicate(struct key *key, const struct key *source)
 
 } /* end user_duplicate() */
 
+/*****************************************************************************/
+/*
+ * dispose of the old data from an updated user defined key
+ */
+static void user_update_rcu_disposal(struct rcu_head *rcu)
+{
+       struct user_key_payload *upayload;
+
+       upayload = container_of(rcu, struct user_key_payload, rcu);
+
+       kfree(upayload);
+
+} /* end user_update_rcu_disposal() */
+
 /*****************************************************************************/
 /*
  * update a user defined key
+ * - the key's semaphore is write-locked
  */
 static int user_update(struct key *key, const void *data, size_t datalen)
 {
-       void *new, *zap;
+       struct user_key_payload *upayload, *zap;
        int ret;
 
        ret = -EINVAL;
        if (datalen <= 0 || datalen > 32767 || !data)
                goto error;
 
-       /* copy the data */
+       /* construct a replacement payload */
        ret = -ENOMEM;
-       new = kmalloc(datalen, GFP_KERNEL);
-       if (!new)
+       upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+       if (!upayload)
                goto error;
 
-       memcpy(new, data, datalen);
+       upayload->datalen = datalen;
+       memcpy(upayload->data, data, datalen);
 
        /* check the quota and attach the new data */
-       zap = new;
-       write_lock(&key->lock);
+       zap = upayload;
 
        ret = key_payload_reserve(key, datalen);
 
        if (ret == 0) {
                /* attach the new data, displacing the old */
                zap = key->payload.data;
-               key->payload.data = new;
+               rcu_assign_pointer(key->payload.data, upayload);
                key->expiry = 0;
        }
 
-       write_unlock(&key->lock);
-       kfree(zap);
+       call_rcu(&zap->rcu, user_update_rcu_disposal);
 
  error:
        return ret;
@@ -152,13 +184,15 @@ static int user_match(const struct key *key, const void *description)
  */
 static void user_destroy(struct key *key)
 {
-       kfree(key->payload.data);
+       struct user_key_payload *upayload = key->payload.data;
+
+       kfree(upayload);
 
 } /* end user_destroy() */
 
 /*****************************************************************************/
 /*
- * describe the user
+ * describe the user key
  */
 static void user_describe(const struct key *key, struct seq_file *m)
 {
@@ -171,18 +205,23 @@ static void user_describe(const struct key *key, struct seq_file *m)
 /*****************************************************************************/
 /*
  * read the key data
+ * - the key's semaphore is read-locked
  */
 static long user_read(const struct key *key,
                      char __user *buffer, size_t buflen)
 {
-       long ret = key->datalen;
+       struct user_key_payload *upayload;
+       long ret;
+
+       upayload = rcu_dereference(key->payload.data);
+       ret = upayload->datalen;
 
        /* we can return the data as is */
        if (buffer && buflen > 0) {
-               if (buflen > key->datalen)
-                       buflen = key->datalen;
+               if (buflen > upayload->datalen)
+                       buflen = upayload->datalen;
 
-               if (copy_to_user(buffer, key->payload.data, buflen) != 0)
+               if (copy_to_user(buffer, upayload->data, buflen) != 0)
                        ret = -EFAULT;
        }