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: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Reshetova, Elena 2017-07-04 09:34:55 +03:00 committed by David S. Miller
parent 0aeea21ada
commit 1be9246077
3 changed files with 7 additions and 6 deletions

View File

@ -316,7 +316,7 @@ static inline struct inet6_dev *in6_dev_get(const struct net_device *dev)
rcu_read_lock(); rcu_read_lock();
idev = rcu_dereference(dev->ip6_ptr); idev = rcu_dereference(dev->ip6_ptr);
if (idev) if (idev)
atomic_inc(&idev->refcnt); refcount_inc(&idev->refcnt);
rcu_read_unlock(); rcu_read_unlock();
return idev; 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) 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); in6_dev_finish_destroy(idev);
} }
static inline void __in6_dev_put(struct inet6_dev *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) 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); void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp);

View File

@ -17,6 +17,7 @@
#include <net/snmp.h> #include <net/snmp.h>
#include <linux/ipv6.h> #include <linux/ipv6.h>
#include <linux/refcount.h>
/* inet6_dev.if_flags */ /* inet6_dev.if_flags */
@ -187,7 +188,7 @@ struct inet6_dev {
struct ifacaddr6 *ac_list; struct ifacaddr6 *ac_list;
rwlock_t lock; rwlock_t lock;
atomic_t refcnt; refcount_t refcnt;
__u32 if_flags; __u32 if_flags;
int dead; int dead;

View File

@ -426,7 +426,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
} }
/* One reference from device. */ /* One reference from device. */
in6_dev_hold(ndev); refcount_set(&ndev->refcnt, 1);
if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) if (dev->flags & (IFF_NOARP | IFF_LOOPBACK))
ndev->cnf.accept_dad = -1; ndev->cnf.accept_dad = -1;