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e65f7ee39b
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>
89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
/*
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* connector.h
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*
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* 2004-2005 Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __CONNECTOR_H
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#define __CONNECTOR_H
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#include <linux/refcount.h>
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#include <linux/list.h>
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#include <linux/workqueue.h>
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#include <net/sock.h>
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#include <uapi/linux/connector.h>
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#define CN_CBQ_NAMELEN 32
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struct cn_queue_dev {
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atomic_t refcnt;
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unsigned char name[CN_CBQ_NAMELEN];
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struct list_head queue_list;
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spinlock_t queue_lock;
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struct sock *nls;
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};
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struct cn_callback_id {
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unsigned char name[CN_CBQ_NAMELEN];
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struct cb_id id;
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};
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struct cn_callback_entry {
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struct list_head callback_entry;
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refcount_t refcnt;
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struct cn_queue_dev *pdev;
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struct cn_callback_id id;
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void (*callback) (struct cn_msg *, struct netlink_skb_parms *);
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u32 seq, group;
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};
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struct cn_dev {
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struct cb_id id;
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u32 seq, groups;
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struct sock *nls;
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void (*input) (struct sk_buff *skb);
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struct cn_queue_dev *cbdev;
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};
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int cn_add_callback(struct cb_id *id, const char *name,
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void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
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void cn_del_callback(struct cb_id *);
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int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, u32 group, gfp_t gfp_mask);
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int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask);
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int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
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struct cb_id *id,
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void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
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void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id);
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void cn_queue_release_callback(struct cn_callback_entry *);
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struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *);
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void cn_queue_free_dev(struct cn_queue_dev *dev);
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int cn_cb_equal(struct cb_id *, struct cb_id *);
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#endif /* __CONNECTOR_H */
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