diff options
| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-12-20 22:10:56 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-20 23:23:44 +0300 |
| commit | ae6959273a29426813974211e41e28f495bc10a6 (patch) | |
| tree | e930b0269e261053504b44185a69f6bc2a7b0deb /drivers/s390 | |
| parent | c380cd5a00f32a96b6c63148a939eb9f8836e184 (diff) | |
| download | linux-ae6959273a29426813974211e41e28f495bc10a6.tar.xz | |
qeth: convert qeth_reply.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 qeth_reply.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>
[jwi: removed the WARN_ONs. Use CONFIG_REFCOUNT_FULL if you care.]
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/s390')
| -rw-r--r-- | drivers/s390/net/qeth_core.h | 3 | ||||
| -rw-r--r-- | drivers/s390/net/qeth_core_main.c | 8 |
2 files changed, 5 insertions, 6 deletions
diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h index badf42acbf95..f5ee62c98011 100644 --- a/drivers/s390/net/qeth_core.h +++ b/drivers/s390/net/qeth_core.h @@ -21,6 +21,7 @@ #include <linux/ethtool.h> #include <linux/hashtable.h> #include <linux/ip.h> +#include <linux/refcount.h> #include <net/ipv6.h> #include <net/if_inet6.h> @@ -632,7 +633,7 @@ struct qeth_reply { int rc; void *param; struct qeth_card *card; - atomic_t refcnt; + refcount_t refcnt; }; struct qeth_card_blkt { diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 6c815207f4f5..bc4e57540a9e 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -564,7 +564,7 @@ static struct qeth_reply *qeth_alloc_reply(struct qeth_card *card) reply = kzalloc(sizeof(struct qeth_reply), GFP_ATOMIC); if (reply) { - atomic_set(&reply->refcnt, 1); + refcount_set(&reply->refcnt, 1); atomic_set(&reply->received, 0); reply->card = card; } @@ -573,14 +573,12 @@ static struct qeth_reply *qeth_alloc_reply(struct qeth_card *card) static void qeth_get_reply(struct qeth_reply *reply) { - WARN_ON(atomic_read(&reply->refcnt) <= 0); - atomic_inc(&reply->refcnt); + refcount_inc(&reply->refcnt); } static void qeth_put_reply(struct qeth_reply *reply) { - WARN_ON(atomic_read(&reply->refcnt) <= 0); - if (atomic_dec_and_test(&reply->refcnt)) + if (refcount_dec_and_test(&reply->refcnt)) kfree(reply); } |