diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_core.c')
-rw-r--r-- | net/netfilter/nf_conntrack_core.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 082a2fd8d85b..369aeabb94fe 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -729,6 +729,9 @@ static void nf_ct_gc_expired(struct nf_conn *ct) if (!refcount_inc_not_zero(&ct->ct_general.use)) return; + /* load ->status after refcount increase */ + smp_acquire__after_ctrl_dep(); + if (nf_ct_should_gc(ct)) nf_ct_kill(ct); @@ -795,6 +798,9 @@ __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, */ ct = nf_ct_tuplehash_to_ctrack(h); if (likely(refcount_inc_not_zero(&ct->ct_general.use))) { + /* re-check key after refcount */ + smp_acquire__after_ctrl_dep(); + if (likely(nf_ct_key_equal(h, tuple, zone, net))) goto found; @@ -1387,6 +1393,9 @@ static unsigned int early_drop_list(struct net *net, if (!refcount_inc_not_zero(&tmp->ct_general.use)) continue; + /* load ->ct_net and ->status after refcount increase */ + smp_acquire__after_ctrl_dep(); + /* kill only if still in same netns -- might have moved due to * SLAB_TYPESAFE_BY_RCU rules. * @@ -1536,6 +1545,9 @@ static void gc_worker(struct work_struct *work) if (!refcount_inc_not_zero(&tmp->ct_general.use)) continue; + /* load ->status after refcount increase */ + smp_acquire__after_ctrl_dep(); + if (gc_worker_skip_ct(tmp)) { nf_ct_put(tmp); continue; @@ -1775,6 +1787,16 @@ init_conntrack(struct net *net, struct nf_conn *tmpl, if (!exp) __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); + /* Other CPU might have obtained a pointer to this object before it was + * released. Because refcount is 0, refcount_inc_not_zero() will fail. + * + * After refcount_set(1) it will succeed; ensure that zeroing of + * ct->status and the correct ct->net pointer are visible; else other + * core might observe CONFIRMED bit which means the entry is valid and + * in the hash table, but its not (anymore). + */ + smp_wmb(); + /* Now it is going to be associated with an sk_buff, set refcount to 1. */ refcount_set(&ct->ct_general.use, 1); |