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Commit 433cea4d authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net: convert netpoll_info.refcnt from atomic_t to refcount_t 



refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7658b36f

include/linux/netpoll.h

+2 −1
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/interrupt.h>

#include <linux/rcupdate.h>

#include <linux/list.h>

#include <linux/refcount.h>



union inet_addr {

	__u32		all[4];
@@ -34,7 +35,7 @@ struct netpoll { 
};



struct netpoll_info {

	atomic_t refcnt;

	refcount_t refcnt;



	struct semaphore dev_lock;

net/core/netpoll.c

+3 −3
Original line number Diff line number Diff line
@@ -632,7 +632,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) 
		skb_queue_head_init(&npinfo->txq);

		INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);



		atomic_set(&npinfo->refcnt, 1);

		refcount_set(&npinfo->refcnt, 1);



		ops = np->dev->netdev_ops;

		if (ops->ndo_netpoll_setup) {
@@ -642,7 +642,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) 
		}

	} else {

		npinfo = rtnl_dereference(ndev->npinfo);

		atomic_inc(&npinfo->refcnt);

		refcount_inc(&npinfo->refcnt);

	}



	npinfo->netpoll = np;
@@ -821,7 +821,7 @@ void __netpoll_cleanup(struct netpoll *np) 


	synchronize_srcu(&netpoll_srcu);



	if (atomic_dec_and_test(&npinfo->refcnt)) {

	if (refcount_dec_and_test(&npinfo->refcnt)) {

		const struct net_device_ops *ops;



		ops = np->dev->netdev_ops;