net, netrom: convert nr_node.refcount 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/netrom.h b/include/net/netrom.h
index cecb4fd..443a4ff 100644 (file)
--- a/include/net/netrom.h
+++ b/include/net/netrom.h
@@ -110,7 +110,7 @@ struct nr_node {
        unsigned char           which;
        unsigned char           count;
        struct nr_route         routes[3];
-       atomic_t                refcount;
+       refcount_t              refcount;
        spinlock_t              node_lock;
 };
 
@@ -119,11 +119,11 @@ struct nr_node {
  *********************************************************************/
 
 #define nr_node_hold(__nr_node) \
-       atomic_inc(&((__nr_node)->refcount))
+       refcount_inc(&((__nr_node)->refcount))
 
 static __inline__ void nr_node_put(struct nr_node *nr_node)
 {
-       if (atomic_dec_and_test(&nr_node->refcount)) {
+       if (refcount_dec_and_test(&nr_node->refcount)) {
                kfree(nr_node);
        }
 }

diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index 6b72970..0c59354 100644 (file)
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -184,7 +184,7 @@ static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
 
                nr_node->which = 0;
                nr_node->count = 1;
-               atomic_set(&nr_node->refcount, 1);
+               refcount_set(&nr_node->refcount, 1);
                spin_lock_init(&nr_node->node_lock);
 
                nr_node->routes[0].quality   = quality;