From 45040978c8994d1401baf5cc5ac71c1495d4e120 Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Wed, 24 Feb 2016 20:32:21 +0100 Subject: [PATCH] netfilter: ipset: Fix set:list type crash when flush/dump set in parallel Flushing/listing entries was not RCU safe, so parallel flush/dump could lead to kernel crash. Bug reported by Deniz Eren. Fixes netfilter bugzilla id #1050. Signed-off-by: Jozsef Kadlecsik --- net/netfilter/ipset/ip_set_core.c | 3 ++ net/netfilter/ipset/ip_set_list_set.c | 55 ++++++++++++++++------------------- 2 files changed, 28 insertions(+), 30 deletions(-) diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index 95db43f..7e6568c 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -985,6 +985,9 @@ static int ip_set_destroy(struct net *net, struct sock *ctnl, if (unlikely(protocol_failed(attr))) return -IPSET_ERR_PROTOCOL; + /* Must wait for flush to be really finished in list:set */ + rcu_barrier(); + /* Commands are serialized and references are * protected by the ip_set_ref_lock. * External systems (i.e. xt_set) must call diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c index bbede95..24c6c19 100644 --- a/net/netfilter/ipset/ip_set_list_set.c +++ b/net/netfilter/ipset/ip_set_list_set.c @@ -30,6 +30,7 @@ MODULE_ALIAS("ip_set_list:set"); struct set_elem { struct rcu_head rcu; struct list_head list; + struct ip_set *set; /* Sigh, in order to cleanup reference */ ip_set_id_t id; } __aligned(__alignof__(u64)); @@ -151,30 +152,29 @@ list_set_kadt(struct ip_set *set, const struct sk_buff *skb, /* Userspace interfaces: we are protected by the nfnl mutex */ static void -__list_set_del(struct ip_set *set, struct set_elem *e) +__list_set_del_rcu(struct rcu_head * rcu) { + struct set_elem *e = container_of(rcu, struct set_elem, rcu); + struct ip_set *set = e->set; struct list_set *map = set->data; ip_set_put_byindex(map->net, e->id); - /* We may call it, because we don't have a to be destroyed - * extension which is used by the kernel. - */ ip_set_ext_destroy(set, e); - kfree_rcu(e, rcu); + kfree(e); } static inline void list_set_del(struct ip_set *set, struct set_elem *e) { list_del_rcu(&e->list); - __list_set_del(set, e); + call_rcu(&e->rcu, __list_set_del_rcu); } static inline void -list_set_replace(struct ip_set *set, struct set_elem *e, struct set_elem *old) +list_set_replace(struct set_elem *e, struct set_elem *old) { list_replace_rcu(&old->list, &e->list); - __list_set_del(set, old); + call_rcu(&old->rcu, __list_set_del_rcu); } static void @@ -244,9 +244,6 @@ list_set_uadd(struct ip_set *set, void *value, const struct ip_set_ext *ext, struct set_elem *e, *n, *prev, *next; bool flag_exist = flags & IPSET_FLAG_EXIST; - if (SET_WITH_TIMEOUT(set)) - set_cleanup_entries(set); - /* Find where to add the new entry */ n = prev = next = NULL; list_for_each_entry(e, &map->members, list) { @@ -301,10 +298,11 @@ list_set_uadd(struct ip_set *set, void *value, const struct ip_set_ext *ext, if (!e) return -ENOMEM; e->id = d->id; + e->set = set; INIT_LIST_HEAD(&e->list); list_set_init_extensions(set, ext, e); if (n) - list_set_replace(set, e, n); + list_set_replace(e, n); else if (next) list_add_tail_rcu(&e->list, &next->list); else if (prev) @@ -431,6 +429,7 @@ list_set_destroy(struct ip_set *set) if (SET_WITH_TIMEOUT(set)) del_timer_sync(&map->gc); + list_for_each_entry_safe(e, n, &map->members, list) { list_del(&e->list); ip_set_put_byindex(map->net, e->id); @@ -450,8 +449,10 @@ list_set_head(struct ip_set *set, struct sk_buff *skb) struct set_elem *e; u32 n = 0; - list_for_each_entry(e, &map->members, list) + rcu_read_lock(); + list_for_each_entry_rcu(e, &map->members, list) n++; + rcu_read_unlock(); nested = ipset_nest_start(skb, IPSET_ATTR_DATA); if (!nested) @@ -483,33 +484,25 @@ list_set_list(const struct ip_set *set, atd = ipset_nest_start(skb, IPSET_ATTR_ADT); if (!atd) return -EMSGSIZE; - list_for_each_entry(e, &map->members, list) { - if (i == first) - break; - i++; - } rcu_read_lock(); - list_for_each_entry_from(e, &map->members, list) { - i++; - if (SET_WITH_TIMEOUT(set) && - ip_set_timeout_expired(ext_timeout(e, set))) + list_for_each_entry_rcu(e, &map->members, list) { + if (i < first || + (SET_WITH_TIMEOUT(set) && + ip_set_timeout_expired(ext_timeout(e, set)))) { + i++; continue; + } nested = ipset_nest_start(skb, IPSET_ATTR_DATA); - if (!nested) { - if (i == first) { - nla_nest_cancel(skb, atd); - ret = -EMSGSIZE; - goto out; - } + if (!nested) goto nla_put_failure; - } if (nla_put_string(skb, IPSET_ATTR_NAME, ip_set_name_byindex(map->net, e->id))) goto nla_put_failure; if (ip_set_put_extensions(skb, set, e, true)) goto nla_put_failure; ipset_nest_end(skb, nested); + i++; } ipset_nest_end(skb, atd); @@ -520,10 +513,12 @@ list_set_list(const struct ip_set *set, nla_put_failure: nla_nest_cancel(skb, nested); if (unlikely(i == first)) { + nla_nest_cancel(skb, atd); cb->args[IPSET_CB_ARG0] = 0; ret = -EMSGSIZE; + } else { + cb->args[IPSET_CB_ARG0] = i; } - cb->args[IPSET_CB_ARG0] = i - 1; ipset_nest_end(skb, atd); out: rcu_read_unlock(); -- 2.7.4