net, ipv6: convert inet6_ifaddr.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>

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 620bd9a..6df79e9 100644 (file)
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -350,18 +350,18 @@ void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp);
 
 static inline void in6_ifa_put(struct inet6_ifaddr *ifp)
 {
-       if (atomic_dec_and_test(&ifp->refcnt))
+       if (refcount_dec_and_test(&ifp->refcnt))
                inet6_ifa_finish_destroy(ifp);
 }
 
 static inline void __in6_ifa_put(struct inet6_ifaddr *ifp)
 {
-       atomic_dec(&ifp->refcnt);
+       refcount_dec(&ifp->refcnt);
 }
 
 static inline void in6_ifa_hold(struct inet6_ifaddr *ifp)
 {
-       atomic_inc(&ifp->refcnt);
+       refcount_inc(&ifp->refcnt);
 }
 
 

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index e7a17b2..2b41cb8 100644 (file)
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -46,7 +46,7 @@ struct inet6_ifaddr {
        /* In seconds, relative to tstamp. Expiry is at tstamp + HZ * lft. */
        __u32                   valid_lft;
        __u32                   prefered_lft;
-       atomic_t                refcnt;
+       refcount_t              refcnt;
        spinlock_t              lock;
 
        int                     state;

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 2365f12..3c46e95 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1050,7 +1050,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 
        ifa->idev = idev;
        /* For caller */
-       in6_ifa_hold(ifa);
+       refcount_set(&ifa->refcnt, 1);
 
        /* Add to big hash table */
        hash = inet6_addr_hash(addr);