net, sched: convert Qdisc.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 15:53:07 +03:00
committed by David S. Miller
parent edcd9270be
commit 7b93640502
3 changed files with 10 additions and 9 deletions

View File

@@ -839,7 +839,7 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
old = dev_graft_qdisc(dev_queue, new);
if (new && i > 0)
atomic_inc(&new->refcnt);
refcount_inc(&new->refcnt);
if (!ingress)
qdisc_destroy(old);
@@ -850,7 +850,7 @@ skip:
notify_and_destroy(net, skb, n, classid,
dev->qdisc, new);
if (new && !new->ops->attach)
atomic_inc(&new->refcnt);
refcount_inc(&new->refcnt);
dev->qdisc = new ? : &noop_qdisc;
if (new && new->ops->attach)
@@ -1259,7 +1259,7 @@ replay:
if (q == p ||
(p && check_loop(q, p, 0)))
return -ELOOP;
atomic_inc(&q->refcnt);
refcount_inc(&q->refcnt);
goto graft;
} else {
if (!q)
@@ -1374,7 +1374,7 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
tcm->tcm_parent = clid;
tcm->tcm_handle = q->handle;
tcm->tcm_info = atomic_read(&q->refcnt);
tcm->tcm_info = refcount_read(&q->refcnt);
if (nla_put_string(skb, TCA_KIND, q->ops->id))
goto nla_put_failure;
if (q->ops->dump && q->ops->dump(q, skb) < 0)