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Commit 1be92460 authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net, ipv6: convert inet6_dev.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 0aeea21a

include/net/addrconf.h

+4 −4
Original line number Diff line number Diff line
@@ -316,7 +316,7 @@ static inline struct inet6_dev *in6_dev_get(const struct net_device *dev) 
	rcu_read_lock();

	idev = rcu_dereference(dev->ip6_ptr);

	if (idev)

		atomic_inc(&idev->refcnt);

		refcount_inc(&idev->refcnt);

	rcu_read_unlock();

	return idev;

}
@@ -332,18 +332,18 @@ void in6_dev_finish_destroy(struct inet6_dev *idev); 


static inline void in6_dev_put(struct inet6_dev *idev)

{

	if (atomic_dec_and_test(&idev->refcnt))

	if (refcount_dec_and_test(&idev->refcnt))

		in6_dev_finish_destroy(idev);

}



static inline void __in6_dev_put(struct inet6_dev *idev)

{

	atomic_dec(&idev->refcnt);

	refcount_dec(&idev->refcnt);

}



static inline void in6_dev_hold(struct inet6_dev *idev)

{

	atomic_inc(&idev->refcnt);

	refcount_inc(&idev->refcnt);

}



void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp);

include/net/if_inet6.h

+2 −1
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 


#include <net/snmp.h>

#include <linux/ipv6.h>

#include <linux/refcount.h>



/* inet6_dev.if_flags */
@@ -187,7 +188,7 @@ struct inet6_dev { 


	struct ifacaddr6	*ac_list;

	rwlock_t		lock;

	atomic_t		refcnt;

	refcount_t		refcnt;

	__u32			if_flags;

	int			dead;

net/ipv6/addrconf.c

+1 −1
Original line number Diff line number Diff line
@@ -426,7 +426,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev) 
	}



	/* One reference from device. */

	in6_dev_hold(ndev);

	refcount_set(&ndev->refcnt, 1);



	if (dev->flags & (IFF_NOARP | IFF_LOOPBACK))

		ndev->cnf.accept_dad = -1;