Commit a4b2b58e authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net, sctp: convert sctp_transport.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 e7f02796

include/net/sctp/structs.h

+1 −1
Original line number Diff line number Diff line
@@ -735,7 +735,7 @@ struct sctp_transport { 
	struct rhlist_head node;



	/* Reference counting. */

	atomic_t refcnt;

	refcount_t refcnt;

		/* RTO-Pending : A flag used to track if one of the DATA

		 *		chunks sent to this address is currently being

		 *		used to compute a RTT. If this flag is 0,

net/sctp/transport.c

+4 −4
Original line number Diff line number Diff line
@@ -99,7 +99,7 @@ static struct sctp_transport *sctp_transport_init(struct net *net, 
	/* Initialize the 64-bit random nonce sent with heartbeat. */

	get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce));



	atomic_set(&peer->refcnt, 1);

	refcount_set(&peer->refcnt, 1);



	return peer;

}
@@ -172,7 +172,7 @@ static void sctp_transport_destroy_rcu(struct rcu_head *head) 
 */

static void sctp_transport_destroy(struct sctp_transport *transport)

{

	if (unlikely(atomic_read(&transport->refcnt))) {

	if (unlikely(refcount_read(&transport->refcnt))) {

		WARN(1, "Attempt to destroy undead transport %p!\n", transport);

		return;

	}
@@ -311,7 +311,7 @@ void sctp_transport_route(struct sctp_transport *transport, 
/* Hold a reference to a transport.  */

int sctp_transport_hold(struct sctp_transport *transport)

{

	return atomic_add_unless(&transport->refcnt, 1, 0);

	return refcount_inc_not_zero(&transport->refcnt);

}



/* Release a reference to a transport and clean up
@@ -319,7 +319,7 @@ int sctp_transport_hold(struct sctp_transport *transport) 
 */

void sctp_transport_put(struct sctp_transport *transport)

{

	if (atomic_dec_and_test(&transport->refcnt))

	if (refcount_dec_and_test(&transport->refcnt))

		sctp_transport_destroy(transport);

}

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