net: convert net.passive 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/net/core/net-sysfs.c b/net/core/net-sysfs.c
index fe7e145..b4f9922 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1448,7 +1448,7 @@ static void *net_grab_current_ns(void)
struct net *ns = current->nsproxy->net_ns;
#ifdef CONFIG_NET_NS
if (ns)
- atomic_inc(&ns->passive);
+ refcount_inc(&ns->passive);
#endif
return ns;
}
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 6a2f412..8726d05 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -284,7 +284,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
LIST_HEAD(net_exit_list);
atomic_set(&net->count, 1);
- atomic_set(&net->passive, 1);
+ refcount_set(&net->passive, 1);
net->dev_base_seq = 1;
net->user_ns = user_ns;
idr_init(&net->netns_ids);
@@ -380,7 +380,7 @@ static void net_free(struct net *net)
void net_drop_ns(void *p)
{
struct net *ns = p;
- if (ns && atomic_dec_and_test(&ns->passive))
+ if (ns && refcount_dec_and_test(&ns->passive))
net_free(ns);
}