aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/connector
diff options
context:
space:
mode:
authorElena Reshetova <elena.reshetova@intel.com>2017-10-20 10:23:49 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-22 02:22:39 +0100
commite65f7ee39b4d7604a78b03ed35d723e1001fc241 (patch)
tree047ba8c6ba1f159c9339923ca939dbb2d81c5897 /drivers/connector
parent709c89b45b874b2f81a074b8802a736009873f48 (diff)
drivers, connector: convert cn_callback_entry.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 cn_callback_entry.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/connector')
-rw-r--r--drivers/connector/cn_queue.c4
-rw-r--r--drivers/connector/connector.c2
2 files changed, 3 insertions, 3 deletions
diff --git a/drivers/connector/cn_queue.c b/drivers/connector/cn_queue.c
index 1f8bf054d11c..9c54fdf7acea 100644
--- a/drivers/connector/cn_queue.c
+++ b/drivers/connector/cn_queue.c
@@ -45,7 +45,7 @@ cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
return NULL;
}
- atomic_set(&cbq->refcnt, 1);
+ refcount_set(&cbq->refcnt, 1);
atomic_inc(&dev->refcnt);
cbq->pdev = dev;
@@ -58,7 +58,7 @@ cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
void cn_queue_release_callback(struct cn_callback_entry *cbq)
{
- if (!atomic_dec_and_test(&cbq->refcnt))
+ if (!refcount_dec_and_test(&cbq->refcnt))
return;
atomic_dec(&cbq->pdev->refcnt);
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 25693b045371..8615594bd065 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -157,7 +157,7 @@ static int cn_call_callback(struct sk_buff *skb)
spin_lock_bh(&dev->cbdev->queue_lock);
list_for_each_entry(i, &dev->cbdev->queue_list, callback_entry) {
if (cn_cb_equal(&i->id.id, &msg->id)) {
- atomic_inc(&i->refcnt);
+ refcount_inc(&i->refcnt);
cbq = i;
break;
}

Privacy Policy