diff options
Diffstat (limited to 'net/netfilter/xt_hashlimit.c')
-rw-r--r-- | net/netfilter/xt_hashlimit.c | 72 |
1 files changed, 53 insertions, 19 deletions
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 26a668a84aa2..f330e8beaf69 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -141,11 +141,10 @@ dsthash_find(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst) { struct dsthash_ent *ent; - struct hlist_node *pos; u_int32_t hash = hash_dst(ht, dst); if (!hlist_empty(&ht->hash[hash])) { - hlist_for_each_entry_rcu(ent, pos, &ht->hash[hash], node) + hlist_for_each_entry_rcu(ent, &ht->hash[hash], node) if (dst_cmp(ent, dst)) { spin_lock(&ent->lock); return ent; @@ -157,11 +156,22 @@ dsthash_find(const struct xt_hashlimit_htable *ht, /* allocate dsthash_ent, initialize dst, put in htable and lock it */ static struct dsthash_ent * dsthash_alloc_init(struct xt_hashlimit_htable *ht, - const struct dsthash_dst *dst) + const struct dsthash_dst *dst, bool *race) { struct dsthash_ent *ent; spin_lock(&ht->lock); + + /* Two or more packets may race to create the same entry in the + * hashtable, double check if this packet lost race. + */ + ent = dsthash_find(ht, dst); + if (ent != NULL) { + spin_unlock(&ht->lock); + *race = true; + return ent; + } + /* initialize hash with random val at the time we allocate * the first hashtable entry */ if (unlikely(!ht->rnd_initialized)) { @@ -286,8 +296,8 @@ static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, spin_lock_bh(&ht->lock); for (i = 0; i < ht->cfg.size; i++) { struct dsthash_ent *dh; - struct hlist_node *pos, *n; - hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) { + struct hlist_node *n; + hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) { if ((*select)(ht, dh)) dsthash_free(ht, dh); } @@ -318,7 +328,10 @@ static void htable_destroy(struct xt_hashlimit_htable *hinfo) parent = hashlimit_net->ipt_hashlimit; else parent = hashlimit_net->ip6t_hashlimit; - remove_proc_entry(hinfo->pde->name, parent); + + if(parent != NULL) + remove_proc_entry(hinfo->pde->name, parent); + htable_selective_cleanup(hinfo, select_all); vfree(hinfo); } @@ -329,9 +342,8 @@ static struct xt_hashlimit_htable *htable_find_get(struct net *net, { struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); struct xt_hashlimit_htable *hinfo; - struct hlist_node *pos; - hlist_for_each_entry(hinfo, pos, &hashlimit_net->htables, node) { + hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) { if (!strcmp(name, hinfo->pde->name) && hinfo->family == family) { hinfo->use++; @@ -585,6 +597,7 @@ hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) unsigned long now = jiffies; struct dsthash_ent *dh; struct dsthash_dst dst; + bool race = false; u32 cost; if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0) @@ -593,13 +606,18 @@ hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) rcu_read_lock_bh(); dh = dsthash_find(hinfo, &dst); if (dh == NULL) { - dh = dsthash_alloc_init(hinfo, &dst); + dh = dsthash_alloc_init(hinfo, &dst, &race); if (dh == NULL) { rcu_read_unlock_bh(); goto hotdrop; + } else if (race) { + /* Already got an entry, update expiration timeout */ + dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); + rateinfo_recalc(dh, now, hinfo->cfg.mode); + } else { + dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire); + rateinfo_init(dh, hinfo); } - dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire); - rateinfo_init(dh, hinfo); } else { /* update expiration timeout */ dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); @@ -801,10 +819,9 @@ static int dl_seq_show(struct seq_file *s, void *v) struct xt_hashlimit_htable *htable = s->private; unsigned int *bucket = (unsigned int *)v; struct dsthash_ent *ent; - struct hlist_node *pos; if (!hlist_empty(&htable->hash[*bucket])) { - hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node) + hlist_for_each_entry(ent, &htable->hash[*bucket], node) if (dl_seq_real_show(ent, htable->family, s)) return -1; } @@ -847,7 +864,7 @@ static int __net_init hashlimit_proc_net_init(struct net *net) #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net); if (!hashlimit_net->ip6t_hashlimit) { - proc_net_remove(net, "ipt_hashlimit"); + remove_proc_entry("ipt_hashlimit", net->proc_net); return -ENOMEM; } #endif @@ -856,9 +873,29 @@ static int __net_init hashlimit_proc_net_init(struct net *net) static void __net_exit hashlimit_proc_net_exit(struct net *net) { - proc_net_remove(net, "ipt_hashlimit"); + struct xt_hashlimit_htable *hinfo; + struct proc_dir_entry *pde; + struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); + + /* recent_net_exit() is called before recent_mt_destroy(). Make sure + * that the parent xt_recent proc entry is is empty before trying to + * remove it. + */ + mutex_lock(&hashlimit_mutex); + pde = hashlimit_net->ipt_hashlimit; + if (pde == NULL) + pde = hashlimit_net->ip6t_hashlimit; + + hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) + remove_proc_entry(hinfo->pde->name, pde); + + hashlimit_net->ipt_hashlimit = NULL; + hashlimit_net->ip6t_hashlimit = NULL; + mutex_unlock(&hashlimit_mutex); + + remove_proc_entry("ipt_hashlimit", net->proc_net); #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) - proc_net_remove(net, "ip6t_hashlimit"); + remove_proc_entry("ip6t_hashlimit", net->proc_net); #endif } @@ -872,9 +909,6 @@ static int __net_init hashlimit_net_init(struct net *net) static void __net_exit hashlimit_net_exit(struct net *net) { - struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); - - BUG_ON(!hlist_empty(&hashlimit_net->htables)); hashlimit_proc_net_exit(net); } |