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[PATCH] Keys: Export user-defined keyring operations 

Export user-defined key operations so that those who wish to define their
own key type based on the user-defined key operations may do so (as has
been requested).

The header file created has been placed into include/keys/user-type.h, thus
creating a directory where other key types may also be placed.  Any
objections to doing this?

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-Off-By: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
David Howells 2005-10-30 15:02:42 -08:00 committed by Linus Torvalds
parent 1426d7a81d
commit 2aa349f6e3
2 changed files with 71 additions and 25 deletions
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47
include/keys/user-type.h Normal file
View File

@ -0,0 +1,47 @@
/* user-type.h: User-defined key type
*
* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _KEYS_USER_TYPE_H
#define _KEYS_USER_TYPE_H
#include <linux/key.h>
#include <linux/rcupdate.h>
/*****************************************************************************/
/*
* the payload for a key of type "user"
* - once filled in and attached to a key:
* - the payload struct is invariant may not be changed, only replaced
* - the payload must be read with RCU procedures or with the key semaphore
* held
* - the payload may only be replaced with the key semaphore write-locked
* - the key's data length is the size of the actual data, not including the
* payload wrapper
*/
struct user_key_payload {
struct rcu_head rcu; /* RCU destructor */
unsigned short datalen; /* length of this data */
char data[0]; /* actual data */
};
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);
extern void user_describe(const struct key *user, struct seq_file *m);
extern long user_read(const struct key *key,
char __user *buffer, size_t buflen);
#endif /* _KEYS_USER_TYPE_H */

49
security/keys/user_defined.c
View File

@ -15,18 +15,10 @@
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <keys/user-type.h>
#include <asm/uaccess.h>
#include "internal.h"
static int user_instantiate(struct key *key, const void *data, size_t datalen);
static int user_duplicate(struct key *key, const struct key *source);
static int user_update(struct key *key, const void *data, size_t datalen);
static int user_match(const struct key *key, const void *criterion);
static void user_destroy(struct key *key);
static void user_describe(const struct key *user, struct seq_file *m);
static long user_read(const struct key *key,
char __user *buffer, size_t buflen);
/*
* user defined keys take an arbitrary string as the description and an
* arbitrary blob of data as the payload
@ -42,19 +34,13 @@ 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)
int user_instantiate(struct key *key, const void *data, size_t datalen)
{
struct user_key_payload *upayload;
int ret;
@ -78,18 +64,20 @@ static int user_instantiate(struct key *key, const void *data, size_t datalen)
rcu_assign_pointer(key->payload.data, upayload);
ret = 0;
error:
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
*/
static int user_duplicate(struct key *key, const struct key *source)
int user_duplicate(struct key *key, const struct key *source)
{
struct user_key_payload *upayload, *spayload;
int ret;
@ -112,6 +100,8 @@ static int user_duplicate(struct key *key, const struct key *source)
} /* end user_duplicate() */
EXPORT_SYMBOL_GPL(user_duplicate);
/*****************************************************************************/
/*
* dispose of the old data from an updated user defined key
@ -131,7 +121,7 @@ static void user_update_rcu_disposal(struct rcu_head *rcu)
* 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)
int user_update(struct key *key, const void *data, size_t datalen)
{
struct user_key_payload *upayload, *zap;
int ret;
@ -163,26 +153,30 @@ static int user_update(struct key *key, const void *data, size_t datalen)
call_rcu(&zap->rcu, user_update_rcu_disposal);
error:
error:
return ret;
} /* end user_update() */
EXPORT_SYMBOL_GPL(user_update);
/*****************************************************************************/
/*
* match users on their name
*/
static int user_match(const struct key *key, const void *description)
int user_match(const struct key *key, const void *description)
{
return strcmp(key->description, description) == 0;
} /* end user_match() */
EXPORT_SYMBOL_GPL(user_match);
/*****************************************************************************/
/*
* dispose of the data dangling from the corpse of a user
*/
static void user_destroy(struct key *key)
void user_destroy(struct key *key)
{
struct user_key_payload *upayload = key->payload.data;
@ -190,11 +184,13 @@ static void user_destroy(struct key *key)
} /* end user_destroy() */
EXPORT_SYMBOL_GPL(user_destroy);
/*****************************************************************************/
/*
* describe the user key
*/
static void user_describe(const struct key *key, struct seq_file *m)
void user_describe(const struct key *key, struct seq_file *m)
{
seq_puts(m, key->description);
@ -202,13 +198,14 @@ static void user_describe(const struct key *key, struct seq_file *m)
} /* end user_describe() */
EXPORT_SYMBOL_GPL(user_describe);
/*****************************************************************************/
/*
* 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 user_read(const struct key *key, char __user *buffer, size_t buflen)
{
struct user_key_payload *upayload;
long ret;
@ -228,3 +225,5 @@ static long user_read(const struct key *key,
return ret;
} /* end user_read() */
EXPORT_SYMBOL_GPL(user_read);