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.reshet...@intel.com> Signed-off-by: Hans Liljestrand <ishkam...@gmail.com> Signed-off-by: Kees Cook <keesc...@chromium.org> Signed-off-by: David Windsor <dwind...@gmail.com> --- include/net/xfrm.h | 9 +++++---- net/xfrm/xfrm_state.c | 4 ++-- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 01fa357..f5272a2 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -13,6 +13,7 @@ #include <linux/mutex.h> #include <linux/audit.h> #include <linux/slab.h> +#include <linux/refcount.h> #include <net/sock.h> #include <net/dst.h> @@ -137,7 +138,7 @@ struct xfrm_state { struct hlist_node bysrc; struct hlist_node byspi; - atomic_t refcnt; + refcount_t refcnt; spinlock_t lock; struct xfrm_id id; @@ -837,18 +838,18 @@ void __xfrm_state_destroy(struct xfrm_state *); static inline void __xfrm_state_put(struct xfrm_state *x) { - atomic_dec(&x->refcnt); + refcount_dec(&x->refcnt); } static inline void xfrm_state_put(struct xfrm_state *x) { - if (atomic_dec_and_test(&x->refcnt)) + if (refcount_dec_and_test(&x->refcnt)) __xfrm_state_destroy(x); } static inline void xfrm_state_hold(struct xfrm_state *x) { - atomic_inc(&x->refcnt); + refcount_inc(&x->refcnt); } static inline bool addr_match(const void *token1, const void *token2, diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 4a28f66..6c0956d 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -48,7 +48,7 @@ static HLIST_HEAD(xfrm_state_gc_list); static inline bool xfrm_state_hold_rcu(struct xfrm_state __rcu *x) { - return atomic_inc_not_zero(&x->refcnt); + return refcount_inc_not_zero(&x->refcnt); } static inline unsigned int xfrm_dst_hash(struct net *net, @@ -558,7 +558,7 @@ struct xfrm_state *xfrm_state_alloc(struct net *net) if (x) { write_pnet(&x->xs_net, net); - atomic_set(&x->refcnt, 1); + refcount_set(&x->refcnt, 1); atomic_set(&x->tunnel_users, 0); INIT_LIST_HEAD(&x->km.all); INIT_HLIST_NODE(&x->bydst); -- 2.7.4