From fb5c2c17a556d9b00798d6a6b9e624281ee2eb28 Mon Sep 17 00:00:00 2001
From: "Reshetova, Elena" <elena.reshetova@intel.com>
Date: Fri, 30 Jun 2017 13:08:10 +0300
Subject: net: convert packet_fanout.sk_ref 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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/packet/internal.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'net/packet/internal.h')

diff --git a/net/packet/internal.h b/net/packet/internal.h
index 9ee46314b7d7..94d1d405a116 100644
--- a/net/packet/internal.h
+++ b/net/packet/internal.h
@@ -1,6 +1,8 @@
 #ifndef __PACKET_INTERNAL_H__
 #define __PACKET_INTERNAL_H__
 
+#include <linux/refcount.h>
+
 struct packet_mclist {
 	struct packet_mclist	*next;
 	int			ifindex;
@@ -86,7 +88,7 @@ struct packet_fanout {
 	struct list_head	list;
 	struct sock		*arr[PACKET_FANOUT_MAX];
 	spinlock_t		lock;
-	atomic_t		sk_ref;
+	refcount_t		sk_ref;
 	struct packet_type	prot_hook ____cacheline_aligned_in_smp;
 };
 
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