From affa78bc6a204fac1b5ced4f34376f53c70ec0ac Mon Sep 17 00:00:00 2001 From: "Reshetova, Elena" Date: Tue, 4 Jul 2017 09:34:58 +0300 Subject: [PATCH] net, ipv6: convert ifacaddr6.aca_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 Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David S. Miller --- include/net/if_inet6.h | 2 +- net/ipv6/anycast.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h index 4bb52ce634e8..d4088d1a688d 100644 --- a/include/net/if_inet6.h +++ b/include/net/if_inet6.h @@ -147,7 +147,7 @@ struct ifacaddr6 { struct rt6_info *aca_rt; struct ifacaddr6 *aca_next; int aca_users; - atomic_t aca_refcnt; + refcount_t aca_refcnt; unsigned long aca_cstamp; unsigned long aca_tstamp; }; diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c index 514ac259f543..0bbab8a4b5d8 100644 --- a/net/ipv6/anycast.c +++ b/net/ipv6/anycast.c @@ -203,12 +203,12 @@ void ipv6_sock_ac_close(struct sock *sk) static void aca_get(struct ifacaddr6 *aca) { - atomic_inc(&aca->aca_refcnt); + refcount_inc(&aca->aca_refcnt); } static void aca_put(struct ifacaddr6 *ac) { - if (atomic_dec_and_test(&ac->aca_refcnt)) { + if (refcount_dec_and_test(&ac->aca_refcnt)) { in6_dev_put(ac->aca_idev); dst_release(&ac->aca_rt->dst); kfree(ac); @@ -232,7 +232,7 @@ static struct ifacaddr6 *aca_alloc(struct rt6_info *rt, aca->aca_users = 1; /* aca_tstamp should be updated upon changes */ aca->aca_cstamp = aca->aca_tstamp = jiffies; - atomic_set(&aca->aca_refcnt, 1); + refcount_set(&aca->aca_refcnt, 1); return aca; } -- 2.20.1