From ddb99e118e37f324a4be65a411bb60ae62795cf9 Mon Sep 17 00:00:00 2001
From: Elena Reshetova <elena.reshetova@intel.com>
Date: Fri, 31 Mar 2017 15:20:49 +0300
Subject: security, keys: convert key_user.usage from atomic_t to refcount_t

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>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
---
 security/keys/internal.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'security/keys/internal.h')

diff --git a/security/keys/internal.h b/security/keys/internal.h
index a2f4c0abb8d8..6bee06ae026d 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -17,6 +17,7 @@
 #include <linux/key-type.h>
 #include <linux/task_work.h>
 #include <linux/keyctl.h>
+#include <linux/refcount.h>
 
 struct iovec;
 
@@ -53,7 +54,7 @@ struct key_user {
 	struct rb_node		node;
 	struct mutex		cons_lock;	/* construction initiation lock */
 	spinlock_t		lock;
-	atomic_t		usage;		/* for accessing qnkeys & qnbytes */
+	refcount_t		usage;		/* for accessing qnkeys & qnbytes */
 	atomic_t		nkeys;		/* number of keys */
 	atomic_t		nikeys;		/* number of instantiated keys */
 	kuid_t			uid;
-- 
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