net, ax25: convert ax25_cb.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>
This commit is contained in:
Reshetova, Elena 2017-07-04 15:53:31 +03:00 committed by David S. Miller
parent 39f25d42c0
commit b6d52ede22
2 changed files with 4 additions and 4 deletions

View File

@ -244,7 +244,7 @@ typedef struct ax25_cb {
unsigned char window;
struct timer_list timer, dtimer;
struct sock *sk; /* Backlink to socket */
atomic_t refcount;
refcount_t refcount;
} ax25_cb;
struct ax25_sock {
@ -266,11 +266,11 @@ static inline struct ax25_cb *sk_to_ax25(const struct sock *sk)
hlist_for_each_entry(__ax25, list, ax25_node)
#define ax25_cb_hold(__ax25) \
atomic_inc(&((__ax25)->refcount))
refcount_inc(&((__ax25)->refcount))
static __inline__ void ax25_cb_put(ax25_cb *ax25)
{
if (atomic_dec_and_test(&ax25->refcount)) {
if (refcount_dec_and_test(&ax25->refcount)) {
kfree(ax25->digipeat);
kfree(ax25);
}

View File

@ -510,7 +510,7 @@ ax25_cb *ax25_create_cb(void)
if ((ax25 = kzalloc(sizeof(*ax25), GFP_ATOMIC)) == NULL)
return NULL;
atomic_set(&ax25->refcount, 1);
refcount_set(&ax25->refcount, 1);
skb_queue_head_init(&ax25->write_queue);
skb_queue_head_init(&ax25->frag_queue);