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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 /include/linux/connector.h
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 'include/linux/connector.h')
-rw-r--r--include/linux/connector.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/connector.h b/include/linux/connector.h
index f8fe8637d771..032102b19645 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -22,7 +22,7 @@
#define __CONNECTOR_H
-#include <linux/atomic.h>
+#include <linux/refcount.h>
#include <linux/list.h>
#include <linux/workqueue.h>
@@ -49,7 +49,7 @@ struct cn_callback_id {
struct cn_callback_entry {
struct list_head callback_entry;
- atomic_t refcnt;
+ refcount_t refcnt;
struct cn_queue_dev *pdev;
struct cn_callback_id id;