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@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: David Windsor <dwindsor@xxxxxxxxx>
---
include/net/sctp/structs.h | 2 +-
net/sctp/transport.c | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 0dfc5c1..6a0d372 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -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,
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 7cdd6bc..80a97c8 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -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);
}
--
2.7.4
--
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