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net, sctp: convert sctp_transport.refcnt from atomic_t to refcount_t

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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 15:53:27 +03:00
committed by David S. Miller
parent e7f0279617
commit a4b2b58efd
2 changed files with 5 additions and 5 deletions
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2
include/net/sctp/structs.h
View File

@@ -735,7 +735,7 @@ struct sctp_transport {
struct rhlist_head node; struct rhlist_head node;
/* Reference counting. */ /* Reference counting. */
atomic_t refcnt; refcount_t refcnt;
/* RTO-Pending : A flag used to track if one of the DATA /* RTO-Pending : A flag used to track if one of the DATA
* chunks sent to this address is currently being * chunks sent to this address is currently being
* used to compute a RTT. If this flag is 0, * used to compute a RTT. If this flag is 0,

8
net/sctp/transport.c
View File

@@ -99,7 +99,7 @@ static struct sctp_transport *sctp_transport_init(struct net *net,
/* Initialize the 64-bit random nonce sent with heartbeat. */ /* Initialize the 64-bit random nonce sent with heartbeat. */
get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce)); get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce));
atomic_set(&peer->refcnt, 1); refcount_set(&peer->refcnt, 1);
return peer; 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) 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); WARN(1, "Attempt to destroy undead transport %p!\n", transport);
return; return;
} }
@@ -311,7 +311,7 @@ void sctp_transport_route(struct sctp_transport *transport,
/* Hold a reference to a transport. */ /* Hold a reference to a transport. */
int sctp_transport_hold(struct sctp_transport *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 /* 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) 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); sctp_transport_destroy(transport);
} }