From: Reshetova, Elena <elena.reshetova@intel.com>
Date: Tue, 4 Jul 2017 06:34:56 +0000 (+0300)
Subject: net, ipv6: convert inet6_ifaddr.refcnt from atomic_t to refcount_t
X-Git-Tag: MMI-PSA29.97-13-9~5285^2~13^2~6
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=271201c09c86cd75e0fd6206bde689176e85aa21;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

net, ipv6: convert inet6_ifaddr.refcnt 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>
---

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 620bd9a83ba9..6df79e96a780 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -350,18 +350,18 @@ void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp);
 
 static inline void in6_ifa_put(struct inet6_ifaddr *ifp)
 {
-	if (atomic_dec_and_test(&ifp->refcnt))
+	if (refcount_dec_and_test(&ifp->refcnt))
 		inet6_ifa_finish_destroy(ifp);
 }
 
 static inline void __in6_ifa_put(struct inet6_ifaddr *ifp)
 {
-	atomic_dec(&ifp->refcnt);
+	refcount_dec(&ifp->refcnt);
 }
 
 static inline void in6_ifa_hold(struct inet6_ifaddr *ifp)
 {
-	atomic_inc(&ifp->refcnt);
+	refcount_inc(&ifp->refcnt);
 }
 
 
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index e7a17b231afc..2b41cb86d62f 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -46,7 +46,7 @@ struct inet6_ifaddr {
 	/* In seconds, relative to tstamp. Expiry is at tstamp + HZ * lft. */
 	__u32			valid_lft;
 	__u32			prefered_lft;
-	atomic_t		refcnt;
+	refcount_t		refcnt;
 	spinlock_t		lock;
 
 	int			state;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 2365f1224c6b..3c46e9513a31 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1050,7 +1050,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 
 	ifa->idev = idev;
 	/* For caller */
-	in6_ifa_hold(ifa);
+	refcount_set(&ifa->refcnt, 1);
 
 	/* Add to big hash table */
 	hash = inet6_addr_hash(addr);