From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B62B2DF15C for ; Fri, 3 Apr 2026 13:45:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775223912; cv=none; b=RsFnT/Ytz1gakYOnaPDOG+mtzjj894lb+Z0tbaIRZV6C/j/nGLPk3t5Fc9FIUcBVNuTaL4tNyM7pjhMJv7asB4G75lfRbMCJPQNRD9Rrs/K5yeBPfGJtQkSp6jJ58gj7NmIwF8I3UlKRT3Z3LGPK1TO2E5JwpdoodjmBb0EgUZ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775223912; c=relaxed/simple; bh=r+V6B06OouK+MmyMblZGORfna2I0Ld0m5iljWm4QJlI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LBHINWJzOG5hnXHh47FEMNDFGu6WOnKoOFZnUsPir6TJweBPtTtg2bJ57x8QYmWkjxjNEayTFiRFNbj6BG4Z0DhAo3hQggivXVBzb3Hr07LyZmzreqyRkBevONsL/wU5sGMPqZSt+RXyX5kcjEMBIWSBck9eouBrrW7CLrws0TI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=strlen.de; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=strlen.de Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id CF38860913; Fri, 03 Apr 2026 15:45:07 +0200 (CEST) Date: Fri, 3 Apr 2026 15:45:07 +0200 From: Florian Westphal To: Scott Mitchell Cc: netfilter-devel@vger.kernel.org Subject: Re: nfnetlink_queue crashes kernel Message-ID: References: Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Florian Westphal wrote: > A probably better fix is to make the rhashtable perqueue, which is > much more intrusive at this late stage. Tentative patch to do this, still misses selftest extensions: diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 47f7f62906e2..15c6276f6592 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -60,29 +60,10 @@ */ #define NFQNL_MAX_COPY_RANGE (0xffff - NLA_HDRLEN) -/* Composite key for packet lookup: (net, queue_num, packet_id) */ -struct nfqnl_packet_key { - possible_net_t net; - u32 packet_id; - u16 queue_num; -} __aligned(sizeof(u32)); /* jhash2 requires 32-bit alignment */ - -/* Global rhashtable - one for entire system, all netns */ -static struct rhashtable nfqnl_packet_map __read_mostly; - -/* Helper to initialize composite key */ -static inline void nfqnl_init_key(struct nfqnl_packet_key *key, - struct net *net, u32 packet_id, u16 queue_num) -{ - memset(key, 0, sizeof(*key)); - write_pnet(&key->net, net); - key->packet_id = packet_id; - key->queue_num = queue_num; -} - struct nfqnl_instance { struct hlist_node hlist; /* global list of queues */ - struct rcu_head rcu; + struct rhashtable nfqnl_packet_map; + struct rcu_work rwork; u32 peer_portid; unsigned int queue_maxlen; @@ -106,6 +87,7 @@ struct nfqnl_instance { typedef int (*nfqnl_cmpfn)(struct nf_queue_entry *, unsigned long); +static struct workqueue_struct *nfq_cleanup_wq __read_mostly; static unsigned int nfnl_queue_net_id __read_mostly; #define INSTANCE_BUCKETS 16 @@ -124,34 +106,10 @@ static inline u_int8_t instance_hashfn(u_int16_t queue_num) return ((queue_num >> 8) ^ queue_num) % INSTANCE_BUCKETS; } -/* Extract composite key from nf_queue_entry for hashing */ -static u32 nfqnl_packet_obj_hashfn(const void *data, u32 len, u32 seed) -{ - const struct nf_queue_entry *entry = data; - struct nfqnl_packet_key key; - - nfqnl_init_key(&key, entry->state.net, entry->id, entry->queue_num); - - return jhash2((u32 *)&key, sizeof(key) / sizeof(u32), seed); -} - -/* Compare stack-allocated key against entry */ -static int nfqnl_packet_obj_cmpfn(struct rhashtable_compare_arg *arg, - const void *obj) -{ - const struct nfqnl_packet_key *key = arg->key; - const struct nf_queue_entry *entry = obj; - - return !net_eq(entry->state.net, read_pnet(&key->net)) || - entry->queue_num != key->queue_num || - entry->id != key->packet_id; -} - static const struct rhashtable_params nfqnl_rhashtable_params = { .head_offset = offsetof(struct nf_queue_entry, hash_node), - .key_len = sizeof(struct nfqnl_packet_key), - .obj_hashfn = nfqnl_packet_obj_hashfn, - .obj_cmpfn = nfqnl_packet_obj_cmpfn, + .key_offset = offsetof(struct nf_queue_entry, id), + .key_len = sizeof(u32), .automatic_shrinking = true, .min_size = NFQNL_HASH_MIN, .max_size = NFQNL_HASH_MAX, @@ -190,7 +148,11 @@ instance_create(struct nfnl_queue_net *q, u_int16_t queue_num, u32 portid) spin_lock_init(&inst->lock); INIT_LIST_HEAD(&inst->queue_list); - spin_lock(&q->instances_lock); + err = rhashtable_init(&inst->nfqnl_packet_map, &nfqnl_rhashtable_params); + if (err < 0) + goto out_free; + + spin_lock_bh(&q->instances_lock); if (instance_lookup(q, queue_num)) { err = -EEXIST; goto out_unlock; @@ -204,12 +166,14 @@ instance_create(struct nfnl_queue_net *q, u_int16_t queue_num, u32 portid) h = instance_hashfn(queue_num); hlist_add_head_rcu(&inst->hlist, &q->instance_table[h]); - spin_unlock(&q->instances_lock); + spin_unlock_bh(&q->instances_lock); return inst; out_unlock: - spin_unlock(&q->instances_lock); + spin_unlock_bh(&q->instances_lock); + rhashtable_destroy(&inst->nfqnl_packet_map); +out_free: kfree(inst); return ERR_PTR(err); } @@ -217,15 +181,18 @@ instance_create(struct nfnl_queue_net *q, u_int16_t queue_num, u32 portid) static void nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn, unsigned long data); -static void -instance_destroy_rcu(struct rcu_head *head) +static void instance_destroy_work(struct work_struct *work) { - struct nfqnl_instance *inst = container_of(head, struct nfqnl_instance, - rcu); + struct nfqnl_instance *inst; + inst = container_of(to_rcu_work(work), struct nfqnl_instance, + rwork); rcu_read_lock(); nfqnl_flush(inst, NULL, 0); rcu_read_unlock(); + + rhashtable_destroy(&inst->nfqnl_packet_map); + kfree(inst); module_put(THIS_MODULE); } @@ -234,7 +201,9 @@ static void __instance_destroy(struct nfqnl_instance *inst) { hlist_del_rcu(&inst->hlist); - call_rcu(&inst->rcu, instance_destroy_rcu); + + INIT_RCU_WORK(&inst->rwork, instance_destroy_work); + queue_rcu_work(nfq_cleanup_wq, &inst->rwork); } static void @@ -250,9 +219,7 @@ __enqueue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry) { int err; - entry->queue_num = queue->queue_num; - - err = rhashtable_insert_fast(&nfqnl_packet_map, &entry->hash_node, + err = rhashtable_insert_fast(&queue->nfqnl_packet_map, &entry->hash_node, nfqnl_rhashtable_params); if (unlikely(err)) return err; @@ -266,23 +233,19 @@ __enqueue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry) static void __dequeue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry) { - rhashtable_remove_fast(&nfqnl_packet_map, &entry->hash_node, + rhashtable_remove_fast(&queue->nfqnl_packet_map, &entry->hash_node, nfqnl_rhashtable_params); list_del(&entry->list); queue->queue_total--; } static struct nf_queue_entry * -find_dequeue_entry(struct nfqnl_instance *queue, unsigned int id, - struct net *net) +find_dequeue_entry(struct nfqnl_instance *queue, unsigned int id) { - struct nfqnl_packet_key key; struct nf_queue_entry *entry; - nfqnl_init_key(&key, net, id, queue->queue_num); - spin_lock_bh(&queue->lock); - entry = rhashtable_lookup_fast(&nfqnl_packet_map, &key, + entry = rhashtable_lookup_fast(&queue->nfqnl_packet_map, &id, nfqnl_rhashtable_params); if (entry) @@ -1531,7 +1494,7 @@ static int nfqnl_recv_verdict(struct sk_buff *skb, const struct nfnl_info *info, verdict = ntohl(vhdr->verdict); - entry = find_dequeue_entry(queue, ntohl(vhdr->id), info->net); + entry = find_dequeue_entry(queue, ntohl(vhdr->id)); if (entry == NULL) return -ENOENT; @@ -1880,40 +1843,38 @@ static int __init nfnetlink_queue_init(void) { int status; - status = rhashtable_init(&nfqnl_packet_map, &nfqnl_rhashtable_params); - if (status < 0) - return status; + nfq_cleanup_wq = alloc_ordered_workqueue("nfq_workqueue", 0); + if (!nfq_cleanup_wq) + return -ENOMEM; status = register_pernet_subsys(&nfnl_queue_net_ops); - if (status < 0) { - pr_err("failed to register pernet ops\n"); - goto cleanup_rhashtable; - } + if (status < 0) + goto cleanup_pernet_subsys; - netlink_register_notifier(&nfqnl_rtnl_notifier); - status = nfnetlink_subsys_register(&nfqnl_subsys); - if (status < 0) { - pr_err("failed to create netlink socket\n"); - goto cleanup_netlink_notifier; - } + status = netlink_register_notifier(&nfqnl_rtnl_notifier); + if (status < 0) + goto cleanup_rtnl_notifier; status = register_netdevice_notifier(&nfqnl_dev_notifier); - if (status < 0) { - pr_err("failed to register netdevice notifier\n"); - goto cleanup_netlink_subsys; - } + if (status < 0) + goto cleanup_dev_notifier; + + status = nfnetlink_subsys_register(&nfqnl_subsys); + if (status < 0) + goto cleanup_nfqnl_subsys; nf_register_queue_handler(&nfqh); return status; -cleanup_netlink_subsys: - nfnetlink_subsys_unregister(&nfqnl_subsys); -cleanup_netlink_notifier: +cleanup_nfqnl_subsys: + netlink_unregister_notifier(&nfqnl_dev_notifier); +cleanup_dev_notifier: netlink_unregister_notifier(&nfqnl_rtnl_notifier); +cleanup_rtnl_notifier: unregister_pernet_subsys(&nfnl_queue_net_ops); -cleanup_rhashtable: - rhashtable_destroy(&nfqnl_packet_map); +cleanup_pernet_subsys: + destroy_workqueue(nfq_cleanup_wq); return status; } @@ -1924,9 +1885,7 @@ static void __exit nfnetlink_queue_fini(void) nfnetlink_subsys_unregister(&nfqnl_subsys); netlink_unregister_notifier(&nfqnl_rtnl_notifier); unregister_pernet_subsys(&nfnl_queue_net_ops); - - rhashtable_destroy(&nfqnl_packet_map); - + destroy_workqueue(nfq_cleanup_wq); rcu_barrier(); /* Wait for completion of call_rcu()'s */ }