Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

1) Fix combination of --reap and --update in xt_recent that triggers
   UAF, from Jozsef Kadlecsik.

2) Fix current year in nft_meta selftest, from Fabian Frederick.

3) Fix possible UAF in the netns destroy path of nftables.

4) Fix incorrect checksum calculation when mangling ports in flowtable,
   from Sven Auhagen.

* git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf:
  netfilter: flowtable: fix tcp and udp header checksum update
  netfilter: nftables: fix possible UAF over chains from packet path in netns
  selftests: netfilter: fix current year
  netfilter: xt_recent: Fix attempt to update deleted entry
====================

Link: https://lore.kernel.org/r/20210205001727.2125-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 31 insertions, 10 deletions

diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
index 513f78db3cb2..4a4acbba78ff 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -399,7 +399,7 @@ static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
 		return -1;
 
 	tcph = (void *)(skb_network_header(skb) + thoff);
-	inet_proto_csum_replace2(&tcph->check, skb, port, new_port, true);
+	inet_proto_csum_replace2(&tcph->check, skb, port, new_port, false);
 
 	return 0;
 }
@@ -415,7 +415,7 @@ static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
 	udph = (void *)(skb_network_header(skb) + thoff);
 	if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 		inet_proto_csum_replace2(&udph->check, skb, port,
-					 new_port, true);
+					 new_port, false);
 		if (!udph->check)
 			udph->check = CSUM_MANGLED_0;
 	}
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 8d3aa97b52e7..43fe80f10313 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8949,6 +8949,17 @@ int __nft_release_basechain(struct nft_ctx *ctx)
 }
 EXPORT_SYMBOL_GPL(__nft_release_basechain);
 
+static void __nft_release_hooks(struct net *net)
+{
+	struct nft_table *table;
+	struct nft_chain *chain;
+
+	list_for_each_entry(table, &net->nft.tables, list) {
+		list_for_each_entry(chain, &table->chains, list)
+			nf_tables_unregister_hook(net, table, chain);
+	}
+}
+
 static void __nft_release_tables(struct net *net)
 {
 	struct nft_flowtable *flowtable, *nf;
@@ -8964,10 +8975,6 @@ static void __nft_release_tables(struct net *net)
 
 	list_for_each_entry_safe(table, nt, &net->nft.tables, list) {
 		ctx.family = table->family;
-
-		list_for_each_entry(chain, &table->chains, list)
-			nf_tables_unregister_hook(net, table, chain);
-		/* No packets are walking on these chains anymore. */
 		ctx.table = table;
 		list_for_each_entry(chain, &table->chains, list) {
 			ctx.chain = chain;
@@ -9016,6 +9023,11 @@ static int __net_init nf_tables_init_net(struct net *net)
 	return 0;
 }
 
+static void __net_exit nf_tables_pre_exit_net(struct net *net)
+{
+	__nft_release_hooks(net);
+}
+
 static void __net_exit nf_tables_exit_net(struct net *net)
 {
 	mutex_lock(&net->nft.commit_mutex);
@@ -9029,8 +9041,9 @@ static void __net_exit nf_tables_exit_net(struct net *net)
 }
 
 static struct pernet_operations nf_tables_net_ops = {
-	.init	= nf_tables_init_net,
-	.exit	= nf_tables_exit_net,
+	.init		= nf_tables_init_net,
+	.pre_exit	= nf_tables_pre_exit_net,
+	.exit		= nf_tables_exit_net,
 };
 
 static int __init nf_tables_module_init(void)
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index 606411869698..0446307516cd 100644
--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -152,7 +152,8 @@ static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
 /*
  * Drop entries with timestamps older then 'time'.
  */
-static void recent_entry_reap(struct recent_table *t, unsigned long time)
+static void recent_entry_reap(struct recent_table *t, unsigned long time,
+			      struct recent_entry *working, bool update)
 {
 	struct recent_entry *e;
 
@@ -162,6 +163,12 @@ static void recent_entry_reap(struct recent_table *t, unsigned long time)
 	e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
 
 	/*
+	 * Do not reap the entry which are going to be updated.
+	 */
+	if (e == working && update)
+		return;
+
+	/*
 	 * The last time stamp is the most recent.
 	 */
 	if (time_after(time, e->stamps[e->index-1]))
@@ -303,7 +310,8 @@ recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
 
 		/* info->seconds must be non-zero */
 		if (info->check_set & XT_RECENT_REAP)
-			recent_entry_reap(t, time);
+			recent_entry_reap(t, time, e,
+				info->check_set & XT_RECENT_UPDATE && ret);
 	}
 
 	if (info->check_set & XT_RECENT_SET ||