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Commit edcb6918 authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net: convert inet_frag_queue.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: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 717d1e99

include/net/inet_frag.h

+2 −2
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ struct inet_frag_queue { 
	spinlock_t		lock;

	struct timer_list	timer;

	struct hlist_node	list;

	atomic_t		refcnt;

	refcount_t		refcnt;

	struct sk_buff		*fragments;

	struct sk_buff		*fragments_tail;

	ktime_t			stamp;
@@ -129,7 +129,7 @@ void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q, 


static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)

{

	if (atomic_dec_and_test(&q->refcnt))

	if (refcount_dec_and_test(&q->refcnt))

		inet_frag_destroy(q, f);

}

net/ipv4/inet_fragment.c

+7 −7
Original line number Diff line number Diff line
@@ -276,11 +276,11 @@ static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f) 
void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)

{

	if (del_timer(&fq->timer))

		atomic_dec(&fq->refcnt);

		refcount_dec(&fq->refcnt);



	if (!(fq->flags & INET_FRAG_COMPLETE)) {

		fq_unlink(fq, f);

		atomic_dec(&fq->refcnt);

		refcount_dec(&fq->refcnt);

	}

}

EXPORT_SYMBOL(inet_frag_kill);
@@ -329,7 +329,7 @@ static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf, 
	 */

	hlist_for_each_entry(qp, &hb->chain, list) {

		if (qp->net == nf && f->match(qp, arg)) {

			atomic_inc(&qp->refcnt);

			refcount_inc(&qp->refcnt);

			spin_unlock(&hb->chain_lock);

			qp_in->flags |= INET_FRAG_COMPLETE;

			inet_frag_put(qp_in, f);
@@ -339,9 +339,9 @@ static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf, 
#endif

	qp = qp_in;

	if (!mod_timer(&qp->timer, jiffies + nf->timeout))

		atomic_inc(&qp->refcnt);

		refcount_inc(&qp->refcnt);



	atomic_inc(&qp->refcnt);

	refcount_inc(&qp->refcnt);

	hlist_add_head(&qp->list, &hb->chain);



	spin_unlock(&hb->chain_lock);
@@ -370,7 +370,7 @@ static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf, 


	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);

	spin_lock_init(&q->lock);

	atomic_set(&q->refcnt, 1);

	refcount_set(&q->refcnt, 1);



	return q;

}
@@ -405,7 +405,7 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, 
	spin_lock(&hb->chain_lock);

	hlist_for_each_entry(q, &hb->chain, list) {

		if (q->net == nf && f->match(q, key)) {

			atomic_inc(&q->refcnt);

			refcount_inc(&q->refcnt);

			spin_unlock(&hb->chain_lock);

			return q;

		}

net/ipv4/ip_fragment.c

+1 −1
Original line number Diff line number Diff line
@@ -312,7 +312,7 @@ static int ip_frag_reinit(struct ipq *qp) 
	unsigned int sum_truesize = 0;



	if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) {

		atomic_inc(&qp->q.refcnt);

		refcount_inc(&qp->q.refcnt);

		return -ETIMEDOUT;

	}