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

Pablo Neira Ayuso says:

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

The following patchset contains Netfilter fixes for net:

1) Do not refresh timeout in SYN_SENT for syn retransmissions.
   Add selftest for unreplied TCP connection, from Florian Westphal.

2) Fix null dereference from error path with hardware offload
   in nftables.

3) Remove useless nf_ct_gre_keymap_flush() from netns exit path,
   from Vasily Averin.

4) Missing rcu read-lock side in ctnetlink helper info dump,
   also from Vasily.

5) Do not mark RST in the reply direction coming after SYN packet
   for an out-of-sync entry, from Ali Abdallah and Florian Westphal.

6) Add tcp_ignore_invalid_rst sysctl to allow to disable out of
   segment RSTs, from Ali.

7) KCSAN fix for nf_conntrack_all_lock(), from Manfred Spraul.

8) Honor NFTA_LAST_SET in nft_last.

9) Fix incorrect arithmetics when restore last_jiffies in nft_last.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/nf_conntrack-sysctl.rst

@@ -110,6 +110,12 @@ nf_conntrack_tcp_be_liberal - BOOLEAN
 	Be conservative in what you do, be liberal in what you accept from others.
 	If it's non-zero, we mark only out of window RST segments as INVALID.
 
+nf_conntrack_tcp_ignore_invalid_rst - BOOLEAN
+	- 0 - disabled (default)
+	- 1 - enabled
+
+	If it's 1, we don't mark out of window RST segments as INVALID.
+
 nf_conntrack_tcp_loose - BOOLEAN
 	- 0 - disabled
 	- not 0 - enabled (default)

include/net/netfilter/nf_conntrack_core.h

@@ -30,7 +30,6 @@ void nf_conntrack_cleanup_net(struct net *net);
 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list);
 
 void nf_conntrack_proto_pernet_init(struct net *net);
-void nf_conntrack_proto_pernet_fini(struct net *net);
 
 int nf_conntrack_proto_init(void);
 void nf_conntrack_proto_fini(void);

include/net/netns/conntrack.h

@@ -27,6 +27,7 @@ struct nf_tcp_net {
 	u8 tcp_loose;
 	u8 tcp_be_liberal;
 	u8 tcp_max_retrans;
+	u8 tcp_ignore_invalid_rst;
 #if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
 	unsigned int offload_timeout;
 	unsigned int offload_pickup;

include/uapi/linux/netfilter/nfnetlink_log.h

@@ -61,7 +61,7 @@ enum nfulnl_attr_type {
 	NFULA_HWTYPE,			/* hardware type */
 	NFULA_HWHEADER,			/* hardware header */
 	NFULA_HWLEN,			/* hardware header length */
-	NFULA_CT,                       /* nf_conntrack_netlink.h */
+	NFULA_CT,                       /* nfnetlink_conntrack.h */
 	NFULA_CT_INFO,                  /* enum ip_conntrack_info */
 	NFULA_VLAN,			/* nested attribute: packet vlan info */
 	NFULA_L2HDR,			/* full L2 header */

include/uapi/linux/netfilter/nfnetlink_queue.h

@@ -51,11 +51,11 @@ enum nfqnl_attr_type {
 	NFQA_IFINDEX_PHYSOUTDEV,	/* __u32 ifindex */
 	NFQA_HWADDR,			/* nfqnl_msg_packet_hw */
 	NFQA_PAYLOAD,			/* opaque data payload */
-	NFQA_CT,			/* nf_conntrack_netlink.h */
+	NFQA_CT,			/* nfnetlink_conntrack.h */
 	NFQA_CT_INFO,			/* enum ip_conntrack_info */
 	NFQA_CAP_LEN,			/* __u32 length of captured packet */
 	NFQA_SKB_INFO,			/* __u32 skb meta information */
-	NFQA_EXP,			/* nf_conntrack_netlink.h */
+	NFQA_EXP,			/* nfnetlink_conntrack.h */
 	NFQA_UID,			/* __u32 sk uid */
 	NFQA_GID,			/* __u32 sk gid */
 	NFQA_SECCTX,			/* security context string */

net/netfilter/nf_conntrack_core.c

@@ -149,7 +149,15 @@ static void nf_conntrack_all_lock(void)
 
 	spin_lock(&nf_conntrack_locks_all_lock);
 
-	nf_conntrack_locks_all = true;
+	/* For nf_contrack_locks_all, only the latest time when another
+	 * CPU will see an update is controlled, by the "release" of the
+	 * spin_lock below.
+	 * The earliest time is not controlled, an thus KCSAN could detect
+	 * a race when nf_conntract_lock() reads the variable.
+	 * WRITE_ONCE() is used to ensure the compiler will not
+	 * optimize the write.
+	 */
+	WRITE_ONCE(nf_conntrack_locks_all, true);
 
 	for (i = 0; i < CONNTRACK_LOCKS; i++) {
 		spin_lock(&nf_conntrack_locks[i]);
@@ -2457,7 +2465,6 @@ i_see_dead_people:
 	}
 
 	list_for_each_entry(net, net_exit_list, exit_list) {
-		nf_conntrack_proto_pernet_fini(net);
 		nf_conntrack_ecache_pernet_fini(net);
 		nf_conntrack_expect_pernet_fini(net);
 		free_percpu(net->ct.stat);

net/netfilter/nf_conntrack_netlink.c

@@ -218,6 +218,7 @@ static int ctnetlink_dump_helpinfo(struct sk_buff *skb,
 	if (!help)
 		return 0;
 
+	rcu_read_lock();
 	helper = rcu_dereference(help->helper);
 	if (!helper)
 		goto out;
@@ -233,9 +234,11 @@ static int ctnetlink_dump_helpinfo(struct sk_buff *skb,
 
 	nla_nest_end(skb, nest_helper);
 out:
+	rcu_read_unlock();
 	return 0;
 
 nla_put_failure:
+	rcu_read_unlock();
 	return -1;
 }
 

net/netfilter/nf_conntrack_proto.c

@@ -697,13 +697,6 @@ void nf_conntrack_proto_pernet_init(struct net *net)
 #endif
 }
 
-void nf_conntrack_proto_pernet_fini(struct net *net)
-{
-#ifdef CONFIG_NF_CT_PROTO_GRE
-	nf_ct_gre_keymap_flush(net);
-#endif
-}
-
 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
 		  &nf_conntrack_htable_size, 0600);
 

net/netfilter/nf_conntrack_proto_gre.c

@@ -55,19 +55,6 @@ static inline struct nf_gre_net *gre_pernet(struct net *net)
 	return &net->ct.nf_ct_proto.gre;
 }
 
-void nf_ct_gre_keymap_flush(struct net *net)
-{
-	struct nf_gre_net *net_gre = gre_pernet(net);
-	struct nf_ct_gre_keymap *km, *tmp;
-
-	spin_lock_bh(&keymap_lock);
-	list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {
-		list_del_rcu(&km->list);
-		kfree_rcu(km, rcu);
-	}
-	spin_unlock_bh(&keymap_lock);
-}
-
 static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
 				const struct nf_conntrack_tuple *t)
 {

net/netfilter/nf_conntrack_proto_tcp.c

@@ -823,6 +823,22 @@ static noinline bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb,
 	return true;
 }
 
+static bool tcp_can_early_drop(const struct nf_conn *ct)
+{
+	switch (ct->proto.tcp.state) {
+	case TCP_CONNTRACK_FIN_WAIT:
+	case TCP_CONNTRACK_LAST_ACK:
+	case TCP_CONNTRACK_TIME_WAIT:
+	case TCP_CONNTRACK_CLOSE:
+	case TCP_CONNTRACK_CLOSE_WAIT:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
 /* Returns verdict for packet, or -1 for invalid. */
 int nf_conntrack_tcp_packet(struct nf_conn *ct,
 			    struct sk_buff *skb,
@@ -1030,10 +1046,30 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
 		if (index != TCP_RST_SET)
 			break;
 
-		if (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) {
+		/* If we are closing, tuple might have been re-used already.
+		 * last_index, last_ack, and all other ct fields used for
+		 * sequence/window validation are outdated in that case.
+		 *
+		 * As the conntrack can already be expired by GC under pressure,
+		 * just skip validation checks.
+		 */
+		if (tcp_can_early_drop(ct))
+			goto in_window;
+
+		/* td_maxack might be outdated if we let a SYN through earlier */
+		if ((ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) &&
+		    ct->proto.tcp.last_index != TCP_SYN_SET) {
 			u32 seq = ntohl(th->seq);
 
-			if (before(seq, ct->proto.tcp.seen[!dir].td_maxack)) {
+			/* If we are not in established state and SEQ=0 this is most
+			 * likely an answer to a SYN we let go through above (last_index
+			 * can be updated due to out-of-order ACKs).
+			 */
+			if (seq == 0 && !nf_conntrack_tcp_established(ct))
+				break;
+
+			if (before(seq, ct->proto.tcp.seen[!dir].td_maxack) &&
+			    !tn->tcp_ignore_invalid_rst) {
 				/* Invalid RST  */
 				spin_unlock_bh(&ct->lock);
 				nf_ct_l4proto_log_invalid(skb, ct, state, "invalid rst");
@@ -1134,6 +1170,16 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
 			nf_ct_kill_acct(ct, ctinfo, skb);
 			return NF_ACCEPT;
 		}
+
+		if (index == TCP_SYN_SET && old_state == TCP_CONNTRACK_SYN_SENT) {
+			/* do not renew timeout on SYN retransmit.
+			 *
+			 * Else port reuse by client or NAT middlebox can keep
+			 * entry alive indefinitely (including nat info).
+			 */
+			return NF_ACCEPT;
+		}
+
 		/* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
 		 * pickup with loose=1. Avoid large ESTABLISHED timeout.
 		 */
@@ -1155,22 +1201,6 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
 	return NF_ACCEPT;
 }
 
-static bool tcp_can_early_drop(const struct nf_conn *ct)
-{
-	switch (ct->proto.tcp.state) {
-	case TCP_CONNTRACK_FIN_WAIT:
-	case TCP_CONNTRACK_LAST_ACK:
-	case TCP_CONNTRACK_TIME_WAIT:
-	case TCP_CONNTRACK_CLOSE:
-	case TCP_CONNTRACK_CLOSE_WAIT:
-		return true;
-	default:
-		break;
-	}
-
-	return false;
-}
-
 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 
 #include <linux/netfilter/nfnetlink.h>
@@ -1437,6 +1467,9 @@ void nf_conntrack_tcp_init_net(struct net *net)
 	 */
 	tn->tcp_be_liberal = 0;
 
+	/* If it's non-zero, we turn off RST sequence number check */
+	tn->tcp_ignore_invalid_rst = 0;
+
 	/* Max number of the retransmitted packets without receiving an (acceptable)
 	 * ACK from the destination. If this number is reached, a shorter timer
 	 * will be started.

net/netfilter/nf_conntrack_standalone.c

@@ -579,6 +579,7 @@ enum nf_ct_sysctl_index {
 #endif
 	NF_SYSCTL_CT_PROTO_TCP_LOOSE,
 	NF_SYSCTL_CT_PROTO_TCP_LIBERAL,
+	NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST,
 	NF_SYSCTL_CT_PROTO_TCP_MAX_RETRANS,
 	NF_SYSCTL_CT_PROTO_TIMEOUT_UDP,
 	NF_SYSCTL_CT_PROTO_TIMEOUT_UDP_STREAM,
@@ -798,6 +799,14 @@ static struct ctl_table nf_ct_sysctl_table[] = {
 		.extra1 	= SYSCTL_ZERO,
 		.extra2 	= SYSCTL_ONE,
 	},
+	[NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST] = {
+		.procname	= "nf_conntrack_tcp_ignore_invalid_rst",
+		.maxlen		= sizeof(u8),
+		.mode		= 0644,
+		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
 	[NF_SYSCTL_CT_PROTO_TCP_MAX_RETRANS] = {
 		.procname	= "nf_conntrack_tcp_max_retrans",
 		.maxlen		= sizeof(u8),
@@ -1004,6 +1013,7 @@ static void nf_conntrack_standalone_init_tcp_sysctl(struct net *net,
 	XASSIGN(LOOSE, &tn->tcp_loose);
 	XASSIGN(LIBERAL, &tn->tcp_be_liberal);
 	XASSIGN(MAX_RETRANS, &tn->tcp_max_retrans);
+	XASSIGN(IGNORE_INVALID_RST, &tn->tcp_ignore_invalid_rst);
 #undef XASSIGN
 
 #if IS_ENABLED(CONFIG_NF_FLOW_TABLE)

net/netfilter/nf_tables_api.c

@@ -3446,7 +3446,8 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
 	return 0;
 
 err_destroy_flow_rule:
-	nft_flow_rule_destroy(flow);
+	if (flow)
+		nft_flow_rule_destroy(flow);
 err_release_rule:
 	nf_tables_rule_release(&ctx, rule);
 err_release_expr:

net/netfilter/nft_last.c

@@ -23,15 +23,21 @@ static int nft_last_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 {
 	struct nft_last_priv *priv = nft_expr_priv(expr);
 	u64 last_jiffies;
+	u32 last_set = 0;
 	int err;
 
-	if (tb[NFTA_LAST_MSECS]) {
+	if (tb[NFTA_LAST_SET]) {
+		last_set = ntohl(nla_get_be32(tb[NFTA_LAST_SET]));
+		if (last_set == 1)
+			priv->last_set = 1;
+	}
+
+	if (last_set && tb[NFTA_LAST_MSECS]) {
 		err = nf_msecs_to_jiffies64(tb[NFTA_LAST_MSECS], &last_jiffies);
 		if (err < 0)
 			return err;
 
-		priv->last_jiffies = jiffies + (unsigned long)last_jiffies;
+		priv->last_jiffies = jiffies - (unsigned long)last_jiffies;
-		priv->last_set = 1;
 	}
 
 	return 0;

tools/testing/selftests/netfilter/Makefile

@@ -5,7 +5,7 @@ TEST_PROGS := nft_trans_stress.sh nft_fib.sh nft_nat.sh bridge_brouter.sh \
 	conntrack_icmp_related.sh nft_flowtable.sh ipvs.sh \
 	nft_concat_range.sh nft_conntrack_helper.sh \
 	nft_queue.sh nft_meta.sh nf_nat_edemux.sh \
-	ipip-conntrack-mtu.sh
+	ipip-conntrack-mtu.sh conntrack_tcp_unreplied.sh
 
 LDLIBS = -lmnl
 TEST_GEN_FILES =  nf-queue

tools/testing/selftests/netfilter/conntrack_tcp_unreplied.sh

@@ -0,0 +1,167 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Check that UNREPLIED tcp conntrack will eventually timeout.
+#
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+ret=0
+
+waittime=20
+sfx=$(mktemp -u "XXXXXXXX")
+ns1="ns1-$sfx"
+ns2="ns2-$sfx"
+
+nft --version > /dev/null 2>&1
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not run test without nft tool"
+	exit $ksft_skip
+fi
+
+ip -Version > /dev/null 2>&1
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not run test without ip tool"
+	exit $ksft_skip
+fi
+
+cleanup() {
+	ip netns pids $ns1 | xargs kill 2>/dev/null
+	ip netns pids $ns2 | xargs kill 2>/dev/null
+
+	ip netns del $ns1
+	ip netns del $ns2
+}
+
+ipv4() {
+    echo -n 192.168.$1.2
+}
+
+check_counter()
+{
+	ns=$1
+	name=$2
+	expect=$3
+	local lret=0
+
+	cnt=$(ip netns exec $ns2 nft list counter inet filter "$name" | grep -q "$expect")
+	if [ $? -ne 0 ]; then
+		echo "ERROR: counter $name in $ns2 has unexpected value (expected $expect)" 1>&2
+		ip netns exec $ns2 nft list counter inet filter "$name" 1>&2
+		lret=1
+	fi
+
+	return $lret
+}
+
+# Create test namespaces
+ip netns add $ns1 || exit 1
+
+trap cleanup EXIT
+
+ip netns add $ns2 || exit 1
+
+# Connect the namespace to the host using a veth pair
+ip -net $ns1 link add name veth1 type veth peer name veth2
+ip -net $ns1 link set netns $ns2 dev veth2
+
+ip -net $ns1 link set up dev lo
+ip -net $ns2 link set up dev lo
+ip -net $ns1 link set up dev veth1
+ip -net $ns2 link set up dev veth2
+
+ip -net $ns2 addr add 10.11.11.2/24 dev veth2
+ip -net $ns2 route add default via 10.11.11.1
+
+ip netns exec $ns2 sysctl -q net.ipv4.conf.veth2.forwarding=1
+
+# add a rule inside NS so we enable conntrack
+ip netns exec $ns1 iptables -A INPUT -m state --state established,related -j ACCEPT
+
+ip -net $ns1 addr add 10.11.11.1/24 dev veth1
+ip -net $ns1 route add 10.99.99.99 via 10.11.11.2
+
+# Check connectivity works
+ip netns exec $ns1 ping -q -c 2 10.11.11.2 >/dev/null || exit 1
+
+ip netns exec $ns2 nc -l -p 8080 < /dev/null &
+
+# however, conntrack entries are there
+
+ip netns exec $ns2 nft -f - <<EOF
+table inet filter {
+	counter connreq { }
+	counter redir { }
+	chain input {
+		type filter hook input priority 0; policy accept;
+		ct state new tcp flags syn ip daddr 10.99.99.99 tcp dport 80 counter name "connreq" accept
+		ct state new ct status dnat tcp dport 8080 counter name "redir" accept
+	}
+}
+EOF
+if [ $? -ne 0 ]; then
+	echo "ERROR: Could not load nft rules"
+	exit 1
+fi
+
+ip netns exec $ns2 sysctl -q net.netfilter.nf_conntrack_tcp_timeout_syn_sent=10
+
+echo "INFO: connect $ns1 -> $ns2 to the virtual ip"
+ip netns exec $ns1 bash -c 'while true ; do
+	nc -p 60000 10.99.99.99 80
+	sleep 1
+	done' &
+
+sleep 1
+
+ip netns exec $ns2 nft -f - <<EOF
+table inet nat {
+	chain prerouting {
+		type nat hook prerouting priority 0; policy accept;
+		ip daddr 10.99.99.99 tcp dport 80 redirect to :8080
+	}
+}
+EOF
+if [ $? -ne 0 ]; then
+	echo "ERROR: Could not load nat redirect"
+	exit 1
+fi
+
+count=$(ip netns exec $ns2 conntrack -L -p tcp --dport 80 2>/dev/null | wc -l)
+if [ $count -eq 0 ]; then
+	echo "ERROR: $ns2 did not pick up tcp connection from peer"
+	exit 1
+fi
+
+echo "INFO: NAT redirect added in ns $ns2, waiting for $waittime seconds for nat to take effect"
+for i in $(seq 1 $waittime); do
+	echo -n "."
+
+	sleep 1
+
+	count=$(ip netns exec $ns2 conntrack -L -p tcp --reply-port-src 8080 2>/dev/null | wc -l)
+	if [ $count -gt 0 ]; then
+		echo
+		echo "PASS: redirection took effect after $i seconds"
+		break
+	fi
+
+	m=$((i%20))
+	if [ $m -eq 0 ]; then
+		echo " waited for $i seconds"
+	fi
+done
+
+expect="packets 1 bytes 60"
+check_counter "$ns2" "redir" "$expect"
+if [ $? -ne 0 ]; then
+	ret=1
+fi
+
+if [ $ret -eq 0 ];then
+	echo "PASS: redirection counter has expected values"
+else
+	echo "ERROR: no tcp connection was redirected"
+fi
+
+exit $ret