kernel_optimize_test/include/linux/connector.h
Elena Reshetova e65f7ee39b drivers, connector: convert cn_callback_entry.refcnt from atomic_t to refcount_t
atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable cn_callback_entry.refcnt is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-22 02:22:39 +01:00

89 lines
2.4 KiB
C

/*
* connector.h
*
* 2004-2005 Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
* All rights reserved.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __CONNECTOR_H
#define __CONNECTOR_H
#include <linux/refcount.h>
#include <linux/list.h>
#include <linux/workqueue.h>
#include <net/sock.h>
#include <uapi/linux/connector.h>
#define CN_CBQ_NAMELEN 32
struct cn_queue_dev {
atomic_t refcnt;
unsigned char name[CN_CBQ_NAMELEN];
struct list_head queue_list;
spinlock_t queue_lock;
struct sock *nls;
};
struct cn_callback_id {
unsigned char name[CN_CBQ_NAMELEN];
struct cb_id id;
};
struct cn_callback_entry {
struct list_head callback_entry;
refcount_t refcnt;
struct cn_queue_dev *pdev;
struct cn_callback_id id;
void (*callback) (struct cn_msg *, struct netlink_skb_parms *);
u32 seq, group;
};
struct cn_dev {
struct cb_id id;
u32 seq, groups;
struct sock *nls;
void (*input) (struct sk_buff *skb);
struct cn_queue_dev *cbdev;
};
int cn_add_callback(struct cb_id *id, const char *name,
void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
void cn_del_callback(struct cb_id *);
int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, u32 group, gfp_t gfp_mask);
int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask);
int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
struct cb_id *id,
void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id);
void cn_queue_release_callback(struct cn_callback_entry *);
struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *);
void cn_queue_free_dev(struct cn_queue_dev *dev);
int cn_cb_equal(struct cb_id *, struct cb_id *);
#endif /* __CONNECTOR_H */