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author | Elena Reshetova <elena.reshetova@intel.com> | 2017-10-20 10:23:44 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-10-22 02:22:39 +0100 |
commit | 8676d76f087f9b2499f056aa0c5d857cffde6806 (patch) | |
tree | 67bd8bcf2a6aadbd9192bbffd9865f83a1ccaf54 /drivers/net | |
parent | e187246f0f7522e306d1d156a2d5edcaf82ba840 (diff) | |
download | op-kernel-dev-8676d76f087f9b2499f056aa0c5d857cffde6806.zip op-kernel-dev-8676d76f087f9b2499f056aa0c5d857cffde6806.tar.gz |
drivers, net: convert masces_rx_sc.refcnt from atomic_t to refcount_t
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable masces_rx_sc.refcnt is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r-- | drivers/net/macsec.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index 733e1c2..e0aeb51 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -172,7 +172,7 @@ struct macsec_rx_sc { bool active; struct macsec_rx_sa __rcu *sa[MACSEC_NUM_AN]; struct pcpu_rx_sc_stats __percpu *stats; - atomic_t refcnt; + refcount_t refcnt; struct rcu_head rcu_head; }; @@ -331,12 +331,12 @@ static void free_rx_sc_rcu(struct rcu_head *head) static struct macsec_rx_sc *macsec_rxsc_get(struct macsec_rx_sc *sc) { - return atomic_inc_not_zero(&sc->refcnt) ? sc : NULL; + return refcount_inc_not_zero(&sc->refcnt) ? sc : NULL; } static void macsec_rxsc_put(struct macsec_rx_sc *sc) { - if (atomic_dec_and_test(&sc->refcnt)) + if (refcount_dec_and_test(&sc->refcnt)) call_rcu(&sc->rcu_head, free_rx_sc_rcu); } @@ -1411,7 +1411,7 @@ static struct macsec_rx_sc *create_rx_sc(struct net_device *dev, sci_t sci) rx_sc->sci = sci; rx_sc->active = true; - atomic_set(&rx_sc->refcnt, 1); + refcount_set(&rx_sc->refcnt, 1); secy = &macsec_priv(dev)->secy; rcu_assign_pointer(rx_sc->next, secy->rx_sc); |