net, ipv6: convert ifacaddr6.aca_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 09:34:58 +03:00 committed by David S. Miller
parent d3981bc615
commit affa78bc6a
2 changed files with 4 additions and 4 deletions

View File

@ -147,7 +147,7 @@ struct ifacaddr6 {
struct rt6_info *aca_rt;
struct ifacaddr6 *aca_next;
int aca_users;
atomic_t aca_refcnt;
refcount_t aca_refcnt;
unsigned long aca_cstamp;
unsigned long aca_tstamp;
};

View File

@ -203,12 +203,12 @@ void ipv6_sock_ac_close(struct sock *sk)
static void aca_get(struct ifacaddr6 *aca)
{
atomic_inc(&aca->aca_refcnt);
refcount_inc(&aca->aca_refcnt);
}
static void aca_put(struct ifacaddr6 *ac)
{
if (atomic_dec_and_test(&ac->aca_refcnt)) {
if (refcount_dec_and_test(&ac->aca_refcnt)) {
in6_dev_put(ac->aca_idev);
dst_release(&ac->aca_rt->dst);
kfree(ac);
@ -232,7 +232,7 @@ static struct ifacaddr6 *aca_alloc(struct rt6_info *rt,
aca->aca_users = 1;
/* aca_tstamp should be updated upon changes */
aca->aca_cstamp = aca->aca_tstamp = jiffies;
atomic_set(&aca->aca_refcnt, 1);
refcount_set(&aca->aca_refcnt, 1);
return aca;
}