Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

7 files changed, 182 insertions, 90 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 22f15ebf6045..4b8d04640ff3 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -144,7 +144,6 @@ config NF_CONNTRACK_ZONES
 
 config NF_CONNTRACK_PROCFS
 	bool "Supply CT list in procfs (OBSOLETE)"
-	default y
 	depends on PROC_FS
 	help
 	This option enables for the list of known conntrack entries
diff --git a/net/netfilter/nf_conntrack_ftp.c b/net/netfilter/nf_conntrack_ftp.c
index a414274338cf..0d9332e9cf71 100644
--- a/net/netfilter/nf_conntrack_ftp.c
+++ b/net/netfilter/nf_conntrack_ftp.c
@@ -34,11 +34,6 @@ MODULE_DESCRIPTION("ftp connection tracking helper");
 MODULE_ALIAS("ip_conntrack_ftp");
 MODULE_ALIAS_NFCT_HELPER(HELPER_NAME);
 
-/* This is slow, but it's simple. --RR */
-static char *ftp_buffer;
-
-static DEFINE_SPINLOCK(nf_ftp_lock);
-
 #define MAX_PORTS 8
 static u_int16_t ports[MAX_PORTS];
 static unsigned int ports_c;
@@ -398,6 +393,9 @@ static int help(struct sk_buff *skb,
 		return NF_ACCEPT;
 	}
 
+	if (unlikely(skb_linearize(skb)))
+		return NF_DROP;
+
 	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
 	if (th == NULL)
 		return NF_ACCEPT;
@@ -411,12 +409,8 @@ static int help(struct sk_buff *skb,
 	}
 	datalen = skb->len - dataoff;
 
-	spin_lock_bh(&nf_ftp_lock);
-	fb_ptr = skb_header_pointer(skb, dataoff, datalen, ftp_buffer);
-	if (!fb_ptr) {
-		spin_unlock_bh(&nf_ftp_lock);
-		return NF_ACCEPT;
-	}
+	spin_lock_bh(&ct->lock);
+	fb_ptr = skb->data + dataoff;
 
 	ends_in_nl = (fb_ptr[datalen - 1] == '\n');
 	seq = ntohl(th->seq) + datalen;
@@ -544,7 +538,7 @@ out_update_nl:
 	if (ends_in_nl)
 		update_nl_seq(ct, seq, ct_ftp_info, dir, skb);
  out:
-	spin_unlock_bh(&nf_ftp_lock);
+	spin_unlock_bh(&ct->lock);
 	return ret;
 }
 
@@ -571,7 +565,6 @@ static const struct nf_conntrack_expect_policy ftp_exp_policy = {
 static void __exit nf_conntrack_ftp_fini(void)
 {
 	nf_conntrack_helpers_unregister(ftp, ports_c * 2);
-	kfree(ftp_buffer);
 }
 
 static int __init nf_conntrack_ftp_init(void)
@@ -580,10 +573,6 @@ static int __init nf_conntrack_ftp_init(void)
 
 	NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_ftp_master));
 
-	ftp_buffer = kmalloc(65536, GFP_KERNEL);
-	if (!ftp_buffer)
-		return -ENOMEM;
-
 	if (ports_c == 0)
 		ports[ports_c++] = FTP_PORT;
 
@@ -603,7 +592,6 @@ static int __init nf_conntrack_ftp_init(void)
 	ret = nf_conntrack_helpers_register(ftp, ports_c * 2);
 	if (ret < 0) {
 		pr_err("failed to register helpers\n");
-		kfree(ftp_buffer);
 		return ret;
 	}
 
diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
index bb76305bb7ff..5a9bce24f3c3 100644
--- a/net/netfilter/nf_conntrack_h323_main.c
+++ b/net/netfilter/nf_conntrack_h323_main.c
@@ -34,6 +34,8 @@
 #include <net/netfilter/nf_conntrack_zones.h>
 #include <linux/netfilter/nf_conntrack_h323.h>
 
+#define H323_MAX_SIZE 65535
+
 /* Parameters */
 static unsigned int default_rrq_ttl __read_mostly = 300;
 module_param(default_rrq_ttl, uint, 0600);
@@ -86,6 +88,9 @@ static int get_tpkt_data(struct sk_buff *skb, unsigned int protoff,
 	if (tcpdatalen <= 0)	/* No TCP data */
 		goto clear_out;
 
+	if (tcpdatalen > H323_MAX_SIZE)
+		tcpdatalen = H323_MAX_SIZE;
+
 	if (*data == NULL) {	/* first TPKT */
 		/* Get first TPKT pointer */
 		tpkt = skb_header_pointer(skb, tcpdataoff, tcpdatalen,
@@ -1169,6 +1174,9 @@ static unsigned char *get_udp_data(struct sk_buff *skb, unsigned int protoff,
 	if (dataoff >= skb->len)
 		return NULL;
 	*datalen = skb->len - dataoff;
+	if (*datalen > H323_MAX_SIZE)
+		*datalen = H323_MAX_SIZE;
+
 	return skb_header_pointer(skb, dataoff, *datalen, h323_buffer);
 }
 
@@ -1770,7 +1778,7 @@ static int __init nf_conntrack_h323_init(void)
 
 	NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_h323_master));
 
-	h323_buffer = kmalloc(65536, GFP_KERNEL);
+	h323_buffer = kmalloc(H323_MAX_SIZE + 1, GFP_KERNEL);
 	if (!h323_buffer)
 		return -ENOMEM;
 	ret = h323_helper_init();
diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c
index 08ee4e760a3d..1796c456ac98 100644
--- a/net/netfilter/nf_conntrack_irc.c
+++ b/net/netfilter/nf_conntrack_irc.c
@@ -39,6 +39,7 @@ unsigned int (*nf_nat_irc_hook)(struct sk_buff *skb,
 EXPORT_SYMBOL_GPL(nf_nat_irc_hook);
 
 #define HELPER_NAME "irc"
+#define MAX_SEARCH_SIZE	4095
 
 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
 MODULE_DESCRIPTION("IRC (DCC) connection tracking helper");
@@ -121,6 +122,7 @@ static int help(struct sk_buff *skb, unsigned int protoff,
 	int i, ret = NF_ACCEPT;
 	char *addr_beg_p, *addr_end_p;
 	typeof(nf_nat_irc_hook) nf_nat_irc;
+	unsigned int datalen;
 
 	/* If packet is coming from IRC server */
 	if (dir == IP_CT_DIR_REPLY)
@@ -140,8 +142,12 @@ static int help(struct sk_buff *skb, unsigned int protoff,
 	if (dataoff >= skb->len)
 		return NF_ACCEPT;
 
+	datalen = skb->len - dataoff;
+	if (datalen > MAX_SEARCH_SIZE)
+		datalen = MAX_SEARCH_SIZE;
+
 	spin_lock_bh(&irc_buffer_lock);
-	ib_ptr = skb_header_pointer(skb, dataoff, skb->len - dataoff,
+	ib_ptr = skb_header_pointer(skb, dataoff, datalen,
 				    irc_buffer);
 	if (!ib_ptr) {
 		spin_unlock_bh(&irc_buffer_lock);
@@ -149,7 +155,7 @@ static int help(struct sk_buff *skb, unsigned int protoff,
 	}
 
 	data = ib_ptr;
-	data_limit = ib_ptr + skb->len - dataoff;
+	data_limit = ib_ptr + datalen;
 
 	/* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24
 	 * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */
@@ -251,7 +257,7 @@ static int __init nf_conntrack_irc_init(void)
 	irc_exp_policy.max_expected = max_dcc_channels;
 	irc_exp_policy.timeout = dcc_timeout;
 
-	irc_buffer = kmalloc(65536, GFP_KERNEL);
+	irc_buffer = kmalloc(MAX_SEARCH_SIZE + 1, GFP_KERNEL);
 	if (!irc_buffer)
 		return -ENOMEM;
 
diff --git a/net/netfilter/nf_conntrack_sane.c b/net/netfilter/nf_conntrack_sane.c
index fcb33b1d5456..13dc421fc4f5 100644
--- a/net/netfilter/nf_conntrack_sane.c
+++ b/net/netfilter/nf_conntrack_sane.c
@@ -34,10 +34,6 @@ MODULE_AUTHOR("Michal Schmidt <mschmidt@redhat.com>");
 MODULE_DESCRIPTION("SANE connection tracking helper");
 MODULE_ALIAS_NFCT_HELPER(HELPER_NAME);
 
-static char *sane_buffer;
-
-static DEFINE_SPINLOCK(nf_sane_lock);
-
 #define MAX_PORTS 8
 static u_int16_t ports[MAX_PORTS];
 static unsigned int ports_c;
@@ -67,14 +63,16 @@ static int help(struct sk_buff *skb,
 	unsigned int dataoff, datalen;
 	const struct tcphdr *th;
 	struct tcphdr _tcph;
-	void *sb_ptr;
 	int ret = NF_ACCEPT;
 	int dir = CTINFO2DIR(ctinfo);
 	struct nf_ct_sane_master *ct_sane_info = nfct_help_data(ct);
 	struct nf_conntrack_expect *exp;
 	struct nf_conntrack_tuple *tuple;
-	struct sane_request *req;
 	struct sane_reply_net_start *reply;
+	union {
+		struct sane_request req;
+		struct sane_reply_net_start repl;
+	} buf;
 
 	/* Until there's been traffic both ways, don't look in packets. */
 	if (ctinfo != IP_CT_ESTABLISHED &&
@@ -92,59 +90,62 @@ static int help(struct sk_buff *skb,
 		return NF_ACCEPT;
 
 	datalen = skb->len - dataoff;
-
-	spin_lock_bh(&nf_sane_lock);
-	sb_ptr = skb_header_pointer(skb, dataoff, datalen, sane_buffer);
-	if (!sb_ptr) {
-		spin_unlock_bh(&nf_sane_lock);
-		return NF_ACCEPT;
-	}
-
 	if (dir == IP_CT_DIR_ORIGINAL) {
+		const struct sane_request *req;
+
 		if (datalen != sizeof(struct sane_request))
-			goto out;
+			return NF_ACCEPT;
+
+		req = skb_header_pointer(skb, dataoff, datalen, &buf.req);
+		if (!req)
+			return NF_ACCEPT;
 
-		req = sb_ptr;
 		if (req->RPC_code != htonl(SANE_NET_START)) {
 			/* Not an interesting command */
-			ct_sane_info->state = SANE_STATE_NORMAL;
-			goto out;
+			WRITE_ONCE(ct_sane_info->state, SANE_STATE_NORMAL);
+			return NF_ACCEPT;
 		}
 
 		/* We're interested in the next reply */
-		ct_sane_info->state = SANE_STATE_START_REQUESTED;
-		goto out;
+		WRITE_ONCE(ct_sane_info->state, SANE_STATE_START_REQUESTED);
+		return NF_ACCEPT;
 	}
 
+	/* IP_CT_DIR_REPLY */
+
 	/* Is it a reply to an uninteresting command? */
-	if (ct_sane_info->state != SANE_STATE_START_REQUESTED)
-		goto out;
+	if (READ_ONCE(ct_sane_info->state) != SANE_STATE_START_REQUESTED)
+		return NF_ACCEPT;
 
 	/* It's a reply to SANE_NET_START. */
-	ct_sane_info->state = SANE_STATE_NORMAL;
+	WRITE_ONCE(ct_sane_info->state, SANE_STATE_NORMAL);
 
 	if (datalen < sizeof(struct sane_reply_net_start)) {
 		pr_debug("NET_START reply too short\n");
-		goto out;
+		return NF_ACCEPT;
 	}
 
-	reply = sb_ptr;
+	datalen = sizeof(struct sane_reply_net_start);
+
+	reply = skb_header_pointer(skb, dataoff, datalen, &buf.repl);
+	if (!reply)
+		return NF_ACCEPT;
+
 	if (reply->status != htonl(SANE_STATUS_SUCCESS)) {
 		/* saned refused the command */
 		pr_debug("unsuccessful SANE_STATUS = %u\n",
 			 ntohl(reply->status));
-		goto out;
+		return NF_ACCEPT;
 	}
 
 	/* Invalid saned reply? Ignore it. */
 	if (reply->zero != 0)
-		goto out;
+		return NF_ACCEPT;
 
 	exp = nf_ct_expect_alloc(ct);
 	if (exp == NULL) {
 		nf_ct_helper_log(skb, ct, "cannot alloc expectation");
-		ret = NF_DROP;
-		goto out;
+		return NF_DROP;
 	}
 
 	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
@@ -162,9 +163,6 @@ static int help(struct sk_buff *skb,
 	}
 
 	nf_ct_expect_put(exp);
-
-out:
-	spin_unlock_bh(&nf_sane_lock);
 	return ret;
 }
 
@@ -178,7 +176,6 @@ static const struct nf_conntrack_expect_policy sane_exp_policy = {
 static void __exit nf_conntrack_sane_fini(void)
 {
 	nf_conntrack_helpers_unregister(sane, ports_c * 2);
-	kfree(sane_buffer);
 }
 
 static int __init nf_conntrack_sane_init(void)
@@ -187,10 +184,6 @@ static int __init nf_conntrack_sane_init(void)
 
 	NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_sane_master));
 
-	sane_buffer = kmalloc(65536, GFP_KERNEL);
-	if (!sane_buffer)
-		return -ENOMEM;
-
 	if (ports_c == 0)
 		ports[ports_c++] = SANE_PORT;
 
@@ -210,7 +203,6 @@ static int __init nf_conntrack_sane_init(void)
 	ret = nf_conntrack_helpers_register(sane, ports_c * 2);
 	if (ret < 0) {
 		pr_err("failed to register helpers\n");
-		kfree(sane_buffer);
 		return ret;
 	}
 
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 3cc88998b879..62cfb0e31c40 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -889,7 +889,7 @@ static int nf_tables_dump_tables(struct sk_buff *skb,
 
 	rcu_read_lock();
 	nft_net = nft_pernet(net);
-	cb->seq = nft_net->base_seq;
+	cb->seq = READ_ONCE(nft_net->base_seq);
 
 	list_for_each_entry_rcu(table, &nft_net->tables, list) {
 		if (family != NFPROTO_UNSPEC && family != table->family)
@@ -1705,7 +1705,7 @@ static int nf_tables_dump_chains(struct sk_buff *skb,
 
 	rcu_read_lock();
 	nft_net = nft_pernet(net);
-	cb->seq = nft_net->base_seq;
+	cb->seq = READ_ONCE(nft_net->base_seq);
 
 	list_for_each_entry_rcu(table, &nft_net->tables, list) {
 		if (family != NFPROTO_UNSPEC && family != table->family)
@@ -3149,7 +3149,7 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
 
 	rcu_read_lock();
 	nft_net = nft_pernet(net);
-	cb->seq = nft_net->base_seq;
+	cb->seq = READ_ONCE(nft_net->base_seq);
 
 	list_for_each_entry_rcu(table, &nft_net->tables, list) {
 		if (family != NFPROTO_UNSPEC && family != table->family)
@@ -3907,7 +3907,7 @@ cont:
 		list_for_each_entry(i, &ctx->table->sets, list) {
 			int tmp;
 
-			if (!nft_is_active_next(ctx->net, set))
+			if (!nft_is_active_next(ctx->net, i))
 				continue;
 			if (!sscanf(i->name, name, &tmp))
 				continue;
@@ -4133,7 +4133,7 @@ static int nf_tables_dump_sets(struct sk_buff *skb, struct netlink_callback *cb)
 
 	rcu_read_lock();
 	nft_net = nft_pernet(net);
-	cb->seq = nft_net->base_seq;
+	cb->seq = READ_ONCE(nft_net->base_seq);
 
 	list_for_each_entry_rcu(table, &nft_net->tables, list) {
 		if (ctx->family != NFPROTO_UNSPEC &&
@@ -4451,6 +4451,11 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
 		err = nf_tables_set_desc_parse(&desc, nla[NFTA_SET_DESC]);
 		if (err < 0)
 			return err;
+
+		if (desc.field_count > 1 && !(flags & NFT_SET_CONCAT))
+			return -EINVAL;
+	} else if (flags & NFT_SET_CONCAT) {
+		return -EINVAL;
 	}
 
 	if (nla[NFTA_SET_EXPR] || nla[NFTA_SET_EXPRESSIONS])
@@ -5061,6 +5066,8 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
 
 	rcu_read_lock();
 	nft_net = nft_pernet(net);
+	cb->seq = READ_ONCE(nft_net->base_seq);
+
 	list_for_each_entry_rcu(table, &nft_net->tables, list) {
 		if (dump_ctx->ctx.family != NFPROTO_UNSPEC &&
 		    dump_ctx->ctx.family != table->family)
@@ -5196,6 +5203,9 @@ static int nft_setelem_parse_flags(const struct nft_set *set,
 	if (!(set->flags & NFT_SET_INTERVAL) &&
 	    *flags & NFT_SET_ELEM_INTERVAL_END)
 		return -EINVAL;
+	if ((*flags & (NFT_SET_ELEM_INTERVAL_END | NFT_SET_ELEM_CATCHALL)) ==
+	    (NFT_SET_ELEM_INTERVAL_END | NFT_SET_ELEM_CATCHALL))
+		return -EINVAL;
 
 	return 0;
 }
@@ -5599,7 +5609,7 @@ int nft_set_elem_expr_clone(const struct nft_ctx *ctx, struct nft_set *set,
 
 		err = nft_expr_clone(expr, set->exprs[i]);
 		if (err < 0) {
-			nft_expr_destroy(ctx, expr);
+			kfree(expr);
 			goto err_expr;
 		}
 		expr_array[i] = expr;
@@ -5842,6 +5852,24 @@ static void nft_setelem_remove(const struct net *net,
 		set->ops->remove(net, set, elem);
 }
 
+static bool nft_setelem_valid_key_end(const struct nft_set *set,
+				      struct nlattr **nla, u32 flags)
+{
+	if ((set->flags & (NFT_SET_CONCAT | NFT_SET_INTERVAL)) ==
+			  (NFT_SET_CONCAT | NFT_SET_INTERVAL)) {
+		if (flags & NFT_SET_ELEM_INTERVAL_END)
+			return false;
+		if (!nla[NFTA_SET_ELEM_KEY_END] &&
+		    !(flags & NFT_SET_ELEM_CATCHALL))
+			return false;
+	} else {
+		if (nla[NFTA_SET_ELEM_KEY_END])
+			return false;
+	}
+
+	return true;
+}
+
 static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 			    const struct nlattr *attr, u32 nlmsg_flags)
 {
@@ -5892,6 +5920,18 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 			return -EINVAL;
 	}
 
+	if (set->flags & NFT_SET_OBJECT) {
+		if (!nla[NFTA_SET_ELEM_OBJREF] &&
+		    !(flags & NFT_SET_ELEM_INTERVAL_END))
+			return -EINVAL;
+	} else {
+		if (nla[NFTA_SET_ELEM_OBJREF])
+			return -EINVAL;
+	}
+
+	if (!nft_setelem_valid_key_end(set, nla, flags))
+		return -EINVAL;
+
 	if ((flags & NFT_SET_ELEM_INTERVAL_END) &&
 	     (nla[NFTA_SET_ELEM_DATA] ||
 	      nla[NFTA_SET_ELEM_OBJREF] ||
@@ -5899,6 +5939,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 	      nla[NFTA_SET_ELEM_EXPIRATION] ||
 	      nla[NFTA_SET_ELEM_USERDATA] ||
 	      nla[NFTA_SET_ELEM_EXPR] ||
+	      nla[NFTA_SET_ELEM_KEY_END] ||
 	      nla[NFTA_SET_ELEM_EXPRESSIONS]))
 		return -EINVAL;
 
@@ -6029,10 +6070,6 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 	}
 
 	if (nla[NFTA_SET_ELEM_OBJREF] != NULL) {
-		if (!(set->flags & NFT_SET_OBJECT)) {
-			err = -EINVAL;
-			goto err_parse_key_end;
-		}
 		obj = nft_obj_lookup(ctx->net, ctx->table,
 				     nla[NFTA_SET_ELEM_OBJREF],
 				     set->objtype, genmask);
@@ -6325,6 +6362,9 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
 	if (!nla[NFTA_SET_ELEM_KEY] && !(flags & NFT_SET_ELEM_CATCHALL))
 		return -EINVAL;
 
+	if (!nft_setelem_valid_key_end(set, nla, flags))
+		return -EINVAL;
+
 	nft_set_ext_prepare(&tmpl);
 
 	if (flags != 0) {
@@ -6941,7 +6981,7 @@ static int nf_tables_dump_obj(struct sk_buff *skb, struct netlink_callback *cb)
 
 	rcu_read_lock();
 	nft_net = nft_pernet(net);
-	cb->seq = nft_net->base_seq;
+	cb->seq = READ_ONCE(nft_net->base_seq);
 
 	list_for_each_entry_rcu(table, &nft_net->tables, list) {
 		if (family != NFPROTO_UNSPEC && family != table->family)
@@ -7873,7 +7913,7 @@ static int nf_tables_dump_flowtable(struct sk_buff *skb,
 
 	rcu_read_lock();
 	nft_net = nft_pernet(net);
-	cb->seq = nft_net->base_seq;
+	cb->seq = READ_ONCE(nft_net->base_seq);
 
 	list_for_each_entry_rcu(table, &nft_net->tables, list) {
 		if (family != NFPROTO_UNSPEC && family != table->family)
@@ -8806,6 +8846,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 	struct nft_trans_elem *te;
 	struct nft_chain *chain;
 	struct nft_table *table;
+	unsigned int base_seq;
 	LIST_HEAD(adl);
 	int err;
 
@@ -8855,9 +8896,12 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 	 * Bump generation counter, invalidate any dump in progress.
 	 * Cannot fail after this point.
 	 */
-	while (++nft_net->base_seq == 0)
+	base_seq = READ_ONCE(nft_net->base_seq);
+	while (++base_seq == 0)
 		;
 
+	WRITE_ONCE(nft_net->base_seq, base_seq);
+
 	/* step 3. Start new generation, rules_gen_X now in use. */
 	net->nft.gencursor = nft_gencursor_next(net);
 
@@ -9419,13 +9463,9 @@ static int nf_tables_check_loops(const struct nft_ctx *ctx,
 				break;
 			}
 		}
-
-		cond_resched();
 	}
 
 	list_for_each_entry(set, &ctx->table->sets, list) {
-		cond_resched();
-
 		if (!nft_is_active_next(ctx->net, set))
 			continue;
 		if (!(set->flags & NFT_SET_MAP) ||
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index c24b1240908f..9c44518cb70f 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -44,6 +44,10 @@ MODULE_DESCRIPTION("Netfilter messages via netlink socket");
 
 static unsigned int nfnetlink_pernet_id __read_mostly;
 
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+static DEFINE_SPINLOCK(nfnl_grp_active_lock);
+#endif
+
 struct nfnl_net {
 	struct sock *nfnl;
 };
@@ -654,6 +658,44 @@ static void nfnetlink_rcv(struct sk_buff *skb)
 		netlink_rcv_skb(skb, nfnetlink_rcv_msg);
 }
 
+static void nfnetlink_bind_event(struct net *net, unsigned int group)
+{
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+	int type, group_bit;
+	u8 v;
+
+	/* All NFNLGRP_CONNTRACK_* group bits fit into u8.
+	 * The other groups are not relevant and can be ignored.
+	 */
+	if (group >= 8)
+		return;
+
+	type = nfnl_group2type[group];
+
+	switch (type) {
+	case NFNL_SUBSYS_CTNETLINK:
+		break;
+	case NFNL_SUBSYS_CTNETLINK_EXP:
+		break;
+	default:
+		return;
+	}
+
+	group_bit = (1 << group);
+
+	spin_lock(&nfnl_grp_active_lock);
+	v = READ_ONCE(net->ct.ctnetlink_has_listener);
+	if ((v & group_bit) == 0) {
+		v |= group_bit;
+
+		/* read concurrently without nfnl_grp_active_lock held. */
+		WRITE_ONCE(net->ct.ctnetlink_has_listener, v);
+	}
+
+	spin_unlock(&nfnl_grp_active_lock);
+#endif
+}
+
 static int nfnetlink_bind(struct net *net, int group)
 {
 	const struct nfnetlink_subsystem *ss;
@@ -670,28 +712,45 @@ static int nfnetlink_bind(struct net *net, int group)
 	if (!ss)
 		request_module_nowait("nfnetlink-subsys-%d", type);
 
-#ifdef CONFIG_NF_CONNTRACK_EVENTS
-	if (type == NFNL_SUBSYS_CTNETLINK) {
-		nfnl_lock(NFNL_SUBSYS_CTNETLINK);
-		WRITE_ONCE(net->ct.ctnetlink_has_listener, true);
-		nfnl_unlock(NFNL_SUBSYS_CTNETLINK);
-	}
-#endif
+	nfnetlink_bind_event(net, group);
 	return 0;
 }
 
 static void nfnetlink_unbind(struct net *net, int group)
 {
 #ifdef CONFIG_NF_CONNTRACK_EVENTS
+	int type, group_bit;
+
 	if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
 		return;
 
-	if (nfnl_group2type[group] == NFNL_SUBSYS_CTNETLINK) {
-		nfnl_lock(NFNL_SUBSYS_CTNETLINK);
-		if (!nfnetlink_has_listeners(net, group))
-			WRITE_ONCE(net->ct.ctnetlink_has_listener, false);
-		nfnl_unlock(NFNL_SUBSYS_CTNETLINK);
+	type = nfnl_group2type[group];
+
+	switch (type) {
+	case NFNL_SUBSYS_CTNETLINK:
+		break;
+	case NFNL_SUBSYS_CTNETLINK_EXP:
+		break;
+	default:
+		return;
+	}
+
+	/* ctnetlink_has_listener is u8 */
+	if (group >= 8)
+		return;
+
+	group_bit = (1 << group);
+
+	spin_lock(&nfnl_grp_active_lock);
+	if (!nfnetlink_has_listeners(net, group)) {
+		u8 v = READ_ONCE(net->ct.ctnetlink_has_listener);
+
+		v &= ~group_bit;
+
+		/* read concurrently without nfnl_grp_active_lock held. */
+		WRITE_ONCE(net->ct.ctnetlink_has_listener, v);
 	}
+	spin_unlock(&nfnl_grp_active_lock);
 #endif
 }