9 files changed, 768 insertions, 11 deletions

diff --git a/tools/testing/selftests/netfilter/.gitignore b/tools/testing/selftests/netfilter/.gitignore
index 4cb887b57413..4b2928e1c19d 100644
--- a/tools/testing/selftests/netfilter/.gitignore
+++ b/tools/testing/selftests/netfilter/.gitignore
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 nf-queue
 connect_close
+audit_logread
diff --git a/tools/testing/selftests/netfilter/Makefile b/tools/testing/selftests/netfilter/Makefile
index 3686bfa6c58d..bced422b78f7 100644
--- a/tools/testing/selftests/netfilter/Makefile
+++ b/tools/testing/selftests/netfilter/Makefile
@@ -6,13 +6,14 @@ TEST_PROGS := nft_trans_stress.sh nft_fib.sh nft_nat.sh bridge_brouter.sh \
 	nft_concat_range.sh nft_conntrack_helper.sh \
 	nft_queue.sh nft_meta.sh nf_nat_edemux.sh \
 	ipip-conntrack-mtu.sh conntrack_tcp_unreplied.sh \
-	conntrack_vrf.sh nft_synproxy.sh rpath.sh
+	conntrack_vrf.sh nft_synproxy.sh rpath.sh nft_audit.sh \
+	conntrack_sctp_collision.sh xt_string.sh
 
 HOSTPKG_CONFIG := pkg-config
 
 CFLAGS += $(shell $(HOSTPKG_CONFIG) --cflags libmnl 2>/dev/null)
 LDLIBS += $(shell $(HOSTPKG_CONFIG) --libs libmnl 2>/dev/null || echo -lmnl)
 
-TEST_GEN_FILES =  nf-queue connect_close
+TEST_GEN_FILES =  nf-queue connect_close audit_logread sctp_collision
 
 include ../lib.mk
diff --git a/tools/testing/selftests/netfilter/audit_logread.c b/tools/testing/selftests/netfilter/audit_logread.c
new file mode 100644
index 000000000000..a0a880fc2d9d
--- /dev/null
+++ b/tools/testing/selftests/netfilter/audit_logread.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <linux/audit.h>
+#include <linux/netlink.h>
+
+static int fd;
+
+#define MAX_AUDIT_MESSAGE_LENGTH	8970
+struct audit_message {
+	struct nlmsghdr nlh;
+	union {
+		struct audit_status s;
+		char data[MAX_AUDIT_MESSAGE_LENGTH];
+	} u;
+};
+
+int audit_recv(int fd, struct audit_message *rep)
+{
+	struct sockaddr_nl addr;
+	socklen_t addrlen = sizeof(addr);
+	int ret;
+
+	do {
+		ret = recvfrom(fd, rep, sizeof(*rep), 0,
+			       (struct sockaddr *)&addr, &addrlen);
+	} while (ret < 0 && errno == EINTR);
+
+	if (ret < 0 ||
+	    addrlen != sizeof(addr) ||
+	    addr.nl_pid != 0 ||
+	    rep->nlh.nlmsg_type == NLMSG_ERROR) /* short-cut for now */
+		return -1;
+
+	return ret;
+}
+
+int audit_send(int fd, uint16_t type, uint32_t key, uint32_t val)
+{
+	static int seq = 0;
+	struct audit_message msg = {
+		.nlh = {
+			.nlmsg_len   = NLMSG_SPACE(sizeof(msg.u.s)),
+			.nlmsg_type  = type,
+			.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
+			.nlmsg_seq   = ++seq,
+		},
+		.u.s = {
+			.mask    = key,
+			.enabled = key == AUDIT_STATUS_ENABLED ? val : 0,
+			.pid     = key == AUDIT_STATUS_PID ? val : 0,
+		}
+	};
+	struct sockaddr_nl addr = {
+		.nl_family = AF_NETLINK,
+	};
+	int ret;
+
+	do {
+		ret = sendto(fd, &msg, msg.nlh.nlmsg_len, 0,
+			     (struct sockaddr *)&addr, sizeof(addr));
+	} while (ret < 0 && errno == EINTR);
+
+	if (ret != (int)msg.nlh.nlmsg_len)
+		return -1;
+	return 0;
+}
+
+int audit_set(int fd, uint32_t key, uint32_t val)
+{
+	struct audit_message rep = { 0 };
+	int ret;
+
+	ret = audit_send(fd, AUDIT_SET, key, val);
+	if (ret)
+		return ret;
+
+	ret = audit_recv(fd, &rep);
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+
+int readlog(int fd)
+{
+	struct audit_message rep = { 0 };
+	int ret = audit_recv(fd, &rep);
+	const char *sep = "";
+	char *k, *v;
+
+	if (ret < 0)
+		return ret;
+
+	if (rep.nlh.nlmsg_type != AUDIT_NETFILTER_CFG)
+		return 0;
+
+	/* skip the initial "audit(...): " part */
+	strtok(rep.u.data, " ");
+
+	while ((k = strtok(NULL, "="))) {
+		v = strtok(NULL, " ");
+
+		/* these vary and/or are uninteresting, ignore */
+		if (!strcmp(k, "pid") ||
+		    !strcmp(k, "comm") ||
+		    !strcmp(k, "subj"))
+			continue;
+
+		/* strip the varying sequence number */
+		if (!strcmp(k, "table"))
+			*strchrnul(v, ':') = '\0';
+
+		printf("%s%s=%s", sep, k, v);
+		sep = " ";
+	}
+	if (*sep) {
+		printf("\n");
+		fflush(stdout);
+	}
+	return 0;
+}
+
+void cleanup(int sig)
+{
+	audit_set(fd, AUDIT_STATUS_ENABLED, 0);
+	close(fd);
+	if (sig)
+		exit(0);
+}
+
+int main(int argc, char **argv)
+{
+	struct sigaction act = {
+		.sa_handler = cleanup,
+	};
+
+	fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_AUDIT);
+	if (fd < 0) {
+		perror("Can't open netlink socket");
+		return -1;
+	}
+
+	if (sigaction(SIGTERM, &act, NULL) < 0 ||
+	    sigaction(SIGINT, &act, NULL) < 0) {
+		perror("Can't set signal handler");
+		close(fd);
+		return -1;
+	}
+
+	audit_set(fd, AUDIT_STATUS_ENABLED, 1);
+	audit_set(fd, AUDIT_STATUS_PID, getpid());
+
+	while (1)
+		readlog(fd);
+}
diff --git a/tools/testing/selftests/netfilter/config b/tools/testing/selftests/netfilter/config
index 4faf2ce021d9..7c42b1b2c69b 100644
--- a/tools/testing/selftests/netfilter/config
+++ b/tools/testing/selftests/netfilter/config
@@ -6,3 +6,4 @@ CONFIG_NFT_REDIR=m
 CONFIG_NFT_MASQ=m
 CONFIG_NFT_FLOW_OFFLOAD=m
 CONFIG_NF_CT_NETLINK=m
+CONFIG_AUDIT=y
diff --git a/tools/testing/selftests/netfilter/conntrack_sctp_collision.sh b/tools/testing/selftests/netfilter/conntrack_sctp_collision.sh
new file mode 100755
index 000000000000..a924e595cfd8
--- /dev/null
+++ b/tools/testing/selftests/netfilter/conntrack_sctp_collision.sh
@@ -0,0 +1,89 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Testing For SCTP COLLISION SCENARIO as Below:
+#
+#   14:35:47.655279 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [INIT] [init tag: 2017837359]
+#   14:35:48.353250 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [INIT] [init tag: 1187206187]
+#   14:35:48.353275 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [INIT ACK] [init tag: 2017837359]
+#   14:35:48.353283 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [COOKIE ECHO]
+#   14:35:48.353977 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [COOKIE ACK]
+#   14:35:48.855335 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [INIT ACK] [init tag: 164579970]
+#
+# TOPO: SERVER_NS (link0)<--->(link1) ROUTER_NS (link2)<--->(link3) CLIENT_NS
+
+CLIENT_NS=$(mktemp -u client-XXXXXXXX)
+CLIENT_IP="198.51.200.1"
+CLIENT_PORT=1234
+
+SERVER_NS=$(mktemp -u server-XXXXXXXX)
+SERVER_IP="198.51.100.1"
+SERVER_PORT=1234
+
+ROUTER_NS=$(mktemp -u router-XXXXXXXX)
+CLIENT_GW="198.51.200.2"
+SERVER_GW="198.51.100.2"
+
+# setup the topo
+setup() {
+	ip net add $CLIENT_NS
+	ip net add $SERVER_NS
+	ip net add $ROUTER_NS
+	ip -n $SERVER_NS link add link0 type veth peer name link1 netns $ROUTER_NS
+	ip -n $CLIENT_NS link add link3 type veth peer name link2 netns $ROUTER_NS
+
+	ip -n $SERVER_NS link set link0 up
+	ip -n $SERVER_NS addr add $SERVER_IP/24 dev link0
+	ip -n $SERVER_NS route add $CLIENT_IP dev link0 via $SERVER_GW
+
+	ip -n $ROUTER_NS link set link1 up
+	ip -n $ROUTER_NS link set link2 up
+	ip -n $ROUTER_NS addr add $SERVER_GW/24 dev link1
+	ip -n $ROUTER_NS addr add $CLIENT_GW/24 dev link2
+	ip net exec $ROUTER_NS sysctl -wq net.ipv4.ip_forward=1
+
+	ip -n $CLIENT_NS link set link3 up
+	ip -n $CLIENT_NS addr add $CLIENT_IP/24 dev link3
+	ip -n $CLIENT_NS route add $SERVER_IP dev link3 via $CLIENT_GW
+
+	# simulate the delay on OVS upcall by setting up a delay for INIT_ACK with
+	# tc on $SERVER_NS side
+	tc -n $SERVER_NS qdisc add dev link0 root handle 1: htb
+	tc -n $SERVER_NS class add dev link0 parent 1: classid 1:1 htb rate 100mbit
+	tc -n $SERVER_NS filter add dev link0 parent 1: protocol ip u32 match ip protocol 132 \
+		0xff match u8 2 0xff at 32 flowid 1:1
+	tc -n $SERVER_NS qdisc add dev link0 parent 1:1 handle 10: netem delay 1200ms
+
+	# simulate the ctstate check on OVS nf_conntrack
+	ip net exec $ROUTER_NS iptables -A FORWARD -m state --state INVALID,UNTRACKED -j DROP
+	ip net exec $ROUTER_NS iptables -A INPUT -p sctp -j DROP
+
+	# use a smaller number for assoc's max_retrans to reproduce the issue
+	modprobe sctp
+	ip net exec $CLIENT_NS sysctl -wq net.sctp.association_max_retrans=3
+}
+
+cleanup() {
+	ip net exec $CLIENT_NS pkill sctp_collision 2>&1 >/dev/null
+	ip net exec $SERVER_NS pkill sctp_collision 2>&1 >/dev/null
+	ip net del "$CLIENT_NS"
+	ip net del "$SERVER_NS"
+	ip net del "$ROUTER_NS"
+}
+
+do_test() {
+	ip net exec $SERVER_NS ./sctp_collision server \
+		$SERVER_IP $SERVER_PORT $CLIENT_IP $CLIENT_PORT &
+	ip net exec $CLIENT_NS ./sctp_collision client \
+		$CLIENT_IP $CLIENT_PORT $SERVER_IP $SERVER_PORT
+}
+
+# NOTE: one way to work around the issue is set a smaller hb_interval
+# ip net exec $CLIENT_NS sysctl -wq net.sctp.hb_interval=3500
+
+# run the test case
+trap cleanup EXIT
+setup && \
+echo "Test for SCTP Collision in nf_conntrack:" && \
+do_test && echo "PASS!"
+exit $?
diff --git a/tools/testing/selftests/netfilter/nf_nat_edemux.sh b/tools/testing/selftests/netfilter/nf_nat_edemux.sh
index 1092bbcb1fba..a1aa8f4a5828 100755
--- a/tools/testing/selftests/netfilter/nf_nat_edemux.sh
+++ b/tools/testing/selftests/netfilter/nf_nat_edemux.sh
@@ -11,16 +11,18 @@ ret=0
 sfx=$(mktemp -u "XXXXXXXX")
 ns1="ns1-$sfx"
 ns2="ns2-$sfx"
+socatpid=0
 
 cleanup()
 {
+	[ $socatpid -gt 0 ] && kill $socatpid
 	ip netns del $ns1
 	ip netns del $ns2
 }
 
-iperf3 -v > /dev/null 2>&1
+socat -h > /dev/null 2>&1
 if [ $? -ne 0 ];then
-	echo "SKIP: Could not run test without iperf3"
+	echo "SKIP: Could not run test without socat"
 	exit $ksft_skip
 fi
 
@@ -60,8 +62,8 @@ ip netns exec $ns2 ip link set up dev veth2
 ip netns exec $ns2 ip addr add 192.168.1.2/24 dev veth2
 
 # Create a server in one namespace
-ip netns exec $ns1 iperf3 -s > /dev/null 2>&1 &
-iperfs=$!
+ip netns exec $ns1 socat -u TCP-LISTEN:5201,fork OPEN:/dev/null,wronly=1 &
+socatpid=$!
 
 # Restrict source port to just one so we don't have to exhaust
 # all others.
@@ -83,17 +85,43 @@ sleep 1
 # ip daddr:dport will be rewritten to 192.168.1.1 5201
 # NAT must reallocate source port 10000 because
 # 192.168.1.2:10000 -> 192.168.1.1:5201 is already in use
-echo test | ip netns exec $ns2 socat -t 3 -u STDIN TCP:10.96.0.1:443 >/dev/null
+echo test | ip netns exec $ns2 socat -t 3 -u STDIN TCP:10.96.0.1:443,connect-timeout=3 >/dev/null
 ret=$?
 
-kill $iperfs
-
 # Check socat can connect to 10.96.0.1:443 (aka 192.168.1.1:5201).
 if [ $ret -eq 0 ]; then
 	echo "PASS: socat can connect via NAT'd address"
 else
 	echo "FAIL: socat cannot connect via NAT'd address"
-	exit 1
 fi
 
-exit 0
+# check sport clashres.
+ip netns exec $ns1 iptables -t nat -A PREROUTING -p tcp --dport 5202 -j REDIRECT --to-ports 5201
+ip netns exec $ns1 iptables -t nat -A PREROUTING -p tcp --dport 5203 -j REDIRECT --to-ports 5201
+
+sleep 5 | ip netns exec $ns2 socat -t 5 -u STDIN TCP:192.168.1.1:5202,connect-timeout=5 >/dev/null &
+cpid1=$!
+sleep 1
+
+# if connect succeeds, client closes instantly due to EOF on stdin.
+# if connect hangs, it will time out after 5s.
+echo | ip netns exec $ns2 socat -t 3 -u STDIN TCP:192.168.1.1:5203,connect-timeout=5 >/dev/null &
+cpid2=$!
+
+time_then=$(date +%s)
+wait $cpid2
+rv=$?
+time_now=$(date +%s)
+
+# Check how much time has elapsed, expectation is for
+# 'cpid2' to connect and then exit (and no connect delay).
+delta=$((time_now - time_then))
+
+if [ $delta -lt 2 -a $rv -eq 0 ]; then
+	echo "PASS: could connect to service via redirected ports"
+else
+	echo "FAIL: socat cannot connect to service via redirect ($delta seconds elapsed, returned $rv)"
+	ret=1
+fi
+
+exit $ret
diff --git a/tools/testing/selftests/netfilter/nft_audit.sh b/tools/testing/selftests/netfilter/nft_audit.sh
new file mode 100755
index 000000000000..99ed5bd6e840
--- /dev/null
+++ b/tools/testing/selftests/netfilter/nft_audit.sh
@@ -0,0 +1,245 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Check that audit logs generated for nft commands are as expected.
+
+SKIP_RC=4
+RC=0
+
+nft --version >/dev/null 2>&1 || {
+	echo "SKIP: missing nft tool"
+	exit $SKIP_RC
+}
+
+# Run everything in a separate network namespace
+[ "${1}" != "run" ] && { unshare -n "${0}" run; exit $?; }
+
+# give other scripts a chance to finish - audit_logread sees all activity
+sleep 1
+
+logfile=$(mktemp)
+rulefile=$(mktemp)
+echo "logging into $logfile"
+./audit_logread >"$logfile" &
+logread_pid=$!
+trap 'kill $logread_pid; rm -f $logfile $rulefile' EXIT
+exec 3<"$logfile"
+
+do_test() { # (cmd, log)
+	echo -n "testing for cmd: $1 ... "
+	cat <&3 >/dev/null
+	$1 >/dev/null || exit 1
+	sleep 0.1
+	res=$(diff -a -u <(echo "$2") - <&3)
+	[ $? -eq 0 ] && { echo "OK"; return; }
+	echo "FAIL"
+	grep -v '^\(---\|+++\|@@\)' <<< "$res"
+	((RC--))
+}
+
+nft flush ruleset
+
+# adding tables, chains and rules
+
+for table in t1 t2; do
+	do_test "nft add table $table" \
+	"table=$table family=2 entries=1 op=nft_register_table"
+
+	do_test "nft add chain $table c1" \
+	"table=$table family=2 entries=1 op=nft_register_chain"
+
+	do_test "nft add chain $table c2; add chain $table c3" \
+	"table=$table family=2 entries=2 op=nft_register_chain"
+
+	cmd="add rule $table c1 counter"
+
+	do_test "nft $cmd" \
+	"table=$table family=2 entries=1 op=nft_register_rule"
+
+	do_test "nft $cmd; $cmd" \
+	"table=$table family=2 entries=2 op=nft_register_rule"
+
+	cmd=""
+	sep=""
+	for chain in c2 c3; do
+		for i in {1..3}; do
+			cmd+="$sep add rule $table $chain counter"
+			sep=";"
+		done
+	done
+	do_test "nft $cmd" \
+	"table=$table family=2 entries=6 op=nft_register_rule"
+done
+
+for ((i = 0; i < 500; i++)); do
+	echo "add rule t2 c3 counter accept comment \"rule $i\""
+done >$rulefile
+do_test "nft -f $rulefile" \
+'table=t2 family=2 entries=500 op=nft_register_rule'
+
+# adding sets and elements
+
+settype='type inet_service; counter'
+setelem='{ 22, 80, 443 }'
+setblock="{ $settype; elements = $setelem; }"
+do_test "nft add set t1 s $setblock" \
+"table=t1 family=2 entries=4 op=nft_register_set"
+
+do_test "nft add set t1 s2 $setblock; add set t1 s3 { $settype; }" \
+"table=t1 family=2 entries=5 op=nft_register_set"
+
+do_test "nft add element t1 s3 $setelem" \
+"table=t1 family=2 entries=3 op=nft_register_setelem"
+
+# adding counters
+
+do_test 'nft add counter t1 c1' \
+'table=t1 family=2 entries=1 op=nft_register_obj'
+
+do_test 'nft add counter t2 c1; add counter t2 c2' \
+'table=t2 family=2 entries=2 op=nft_register_obj'
+
+for ((i = 3; i <= 500; i++)); do
+	echo "add counter t2 c$i"
+done >$rulefile
+do_test "nft -f $rulefile" \
+'table=t2 family=2 entries=498 op=nft_register_obj'
+
+# adding/updating quotas
+
+do_test 'nft add quota t1 q1 { 10 bytes }' \
+'table=t1 family=2 entries=1 op=nft_register_obj'
+
+do_test 'nft add quota t2 q1 { 10 bytes }; add quota t2 q2 { 10 bytes }' \
+'table=t2 family=2 entries=2 op=nft_register_obj'
+
+for ((i = 3; i <= 500; i++)); do
+	echo "add quota t2 q$i { 10 bytes }"
+done >$rulefile
+do_test "nft -f $rulefile" \
+'table=t2 family=2 entries=498 op=nft_register_obj'
+
+# changing the quota value triggers obj update path
+do_test 'nft add quota t1 q1 { 20 bytes }' \
+'table=t1 family=2 entries=1 op=nft_register_obj'
+
+# resetting rules
+
+do_test 'nft reset rules t1 c2' \
+'table=t1 family=2 entries=3 op=nft_reset_rule'
+
+do_test 'nft reset rules table t1' \
+'table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule'
+
+do_test 'nft reset rules t2 c3' \
+'table=t2 family=2 entries=189 op=nft_reset_rule
+table=t2 family=2 entries=188 op=nft_reset_rule
+table=t2 family=2 entries=126 op=nft_reset_rule'
+
+do_test 'nft reset rules t2' \
+'table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=186 op=nft_reset_rule
+table=t2 family=2 entries=188 op=nft_reset_rule
+table=t2 family=2 entries=129 op=nft_reset_rule'
+
+do_test 'nft reset rules' \
+'table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=180 op=nft_reset_rule
+table=t2 family=2 entries=188 op=nft_reset_rule
+table=t2 family=2 entries=135 op=nft_reset_rule'
+
+# resetting sets and elements
+
+elem=(22 ,80 ,443)
+relem=""
+for i in {1..3}; do
+	relem+="${elem[((i - 1))]}"
+	do_test "nft reset element t1 s { $relem }" \
+	"table=t1 family=2 entries=$i op=nft_reset_setelem"
+done
+
+do_test 'nft reset set t1 s' \
+'table=t1 family=2 entries=3 op=nft_reset_setelem'
+
+# resetting counters
+
+do_test 'nft reset counter t1 c1' \
+'table=t1 family=2 entries=1 op=nft_reset_obj'
+
+do_test 'nft reset counters t1' \
+'table=t1 family=2 entries=1 op=nft_reset_obj'
+
+do_test 'nft reset counters t2' \
+'table=t2 family=2 entries=342 op=nft_reset_obj
+table=t2 family=2 entries=158 op=nft_reset_obj'
+
+do_test 'nft reset counters' \
+'table=t1 family=2 entries=1 op=nft_reset_obj
+table=t2 family=2 entries=341 op=nft_reset_obj
+table=t2 family=2 entries=159 op=nft_reset_obj'
+
+# resetting quotas
+
+do_test 'nft reset quota t1 q1' \
+'table=t1 family=2 entries=1 op=nft_reset_obj'
+
+do_test 'nft reset quotas t1' \
+'table=t1 family=2 entries=1 op=nft_reset_obj'
+
+do_test 'nft reset quotas t2' \
+'table=t2 family=2 entries=315 op=nft_reset_obj
+table=t2 family=2 entries=185 op=nft_reset_obj'
+
+do_test 'nft reset quotas' \
+'table=t1 family=2 entries=1 op=nft_reset_obj
+table=t2 family=2 entries=314 op=nft_reset_obj
+table=t2 family=2 entries=186 op=nft_reset_obj'
+
+# deleting rules
+
+readarray -t handles < <(nft -a list chain t1 c1 | \
+			 sed -n 's/.*counter.* handle \(.*\)$/\1/p')
+
+do_test "nft delete rule t1 c1 handle ${handles[0]}" \
+'table=t1 family=2 entries=1 op=nft_unregister_rule'
+
+cmd='delete rule t1 c1 handle'
+do_test "nft $cmd ${handles[1]}; $cmd ${handles[2]}" \
+'table=t1 family=2 entries=2 op=nft_unregister_rule'
+
+do_test 'nft flush chain t1 c2' \
+'table=t1 family=2 entries=3 op=nft_unregister_rule'
+
+do_test 'nft flush table t2' \
+'table=t2 family=2 entries=509 op=nft_unregister_rule'
+
+# deleting chains
+
+do_test 'nft delete chain t2 c2' \
+'table=t2 family=2 entries=1 op=nft_unregister_chain'
+
+# deleting sets and elements
+
+do_test 'nft delete element t1 s { 22 }' \
+'table=t1 family=2 entries=1 op=nft_unregister_setelem'
+
+do_test 'nft delete element t1 s { 80, 443 }' \
+'table=t1 family=2 entries=2 op=nft_unregister_setelem'
+
+do_test 'nft flush set t1 s2' \
+'table=t1 family=2 entries=3 op=nft_unregister_setelem'
+
+do_test 'nft delete set t1 s2' \
+'table=t1 family=2 entries=1 op=nft_unregister_set'
+
+do_test 'nft delete set t1 s3' \
+'table=t1 family=2 entries=1 op=nft_unregister_set'
+
+exit $RC
diff --git a/tools/testing/selftests/netfilter/sctp_collision.c b/tools/testing/selftests/netfilter/sctp_collision.c
new file mode 100644
index 000000000000..21bb1cfd8a85
--- /dev/null
+++ b/tools/testing/selftests/netfilter/sctp_collision.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+
+int main(int argc, char *argv[])
+{
+	struct sockaddr_in saddr = {}, daddr = {};
+	int sd, ret, len = sizeof(daddr);
+	struct timeval tv = {25, 0};
+	char buf[] = "hello";
+
+	if (argc != 6 || (strcmp(argv[1], "server") && strcmp(argv[1], "client"))) {
+		printf("%s <server|client> <LOCAL_IP> <LOCAL_PORT> <REMOTE_IP> <REMOTE_PORT>\n",
+		       argv[0]);
+		return -1;
+	}
+
+	sd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
+	if (sd < 0) {
+		printf("Failed to create sd\n");
+		return -1;
+	}
+
+	saddr.sin_family = AF_INET;
+	saddr.sin_addr.s_addr = inet_addr(argv[2]);
+	saddr.sin_port = htons(atoi(argv[3]));
+
+	ret = bind(sd, (struct sockaddr *)&saddr, sizeof(saddr));
+	if (ret < 0) {
+		printf("Failed to bind to address\n");
+		goto out;
+	}
+
+	ret = listen(sd, 5);
+	if (ret < 0) {
+		printf("Failed to listen on port\n");
+		goto out;
+	}
+
+	daddr.sin_family = AF_INET;
+	daddr.sin_addr.s_addr = inet_addr(argv[4]);
+	daddr.sin_port = htons(atoi(argv[5]));
+
+	/* make test shorter than 25s */
+	ret = setsockopt(sd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+	if (ret < 0) {
+		printf("Failed to setsockopt SO_RCVTIMEO\n");
+		goto out;
+	}
+
+	if (!strcmp(argv[1], "server")) {
+		sleep(1); /* wait a bit for client's INIT */
+		ret = connect(sd, (struct sockaddr *)&daddr, len);
+		if (ret < 0) {
+			printf("Failed to connect to peer\n");
+			goto out;
+		}
+		ret = recvfrom(sd, buf, sizeof(buf), 0, (struct sockaddr *)&daddr, &len);
+		if (ret < 0) {
+			printf("Failed to recv msg %d\n", ret);
+			goto out;
+		}
+		ret = sendto(sd, buf, strlen(buf) + 1, 0, (struct sockaddr *)&daddr, len);
+		if (ret < 0) {
+			printf("Failed to send msg %d\n", ret);
+			goto out;
+		}
+		printf("Server: sent! %d\n", ret);
+	}
+
+	if (!strcmp(argv[1], "client")) {
+		usleep(300000); /* wait a bit for server's listening */
+		ret = connect(sd, (struct sockaddr *)&daddr, len);
+		if (ret < 0) {
+			printf("Failed to connect to peer\n");
+			goto out;
+		}
+		sleep(1); /* wait a bit for server's delayed INIT_ACK to reproduce the issue */
+		ret = sendto(sd, buf, strlen(buf) + 1, 0, (struct sockaddr *)&daddr, len);
+		if (ret < 0) {
+			printf("Failed to send msg %d\n", ret);
+			goto out;
+		}
+		ret = recvfrom(sd, buf, sizeof(buf), 0, (struct sockaddr *)&daddr, &len);
+		if (ret < 0) {
+			printf("Failed to recv msg %d\n", ret);
+			goto out;
+		}
+		printf("Client: rcvd! %d\n", ret);
+	}
+	ret = 0;
+out:
+	close(sd);
+	return ret;
+}
diff --git a/tools/testing/selftests/netfilter/xt_string.sh b/tools/testing/selftests/netfilter/xt_string.sh
new file mode 100755
index 000000000000..1802653a4728
--- /dev/null
+++ b/tools/testing/selftests/netfilter/xt_string.sh
@@ -0,0 +1,128 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# return code to signal skipped test
+ksft_skip=4
+rc=0
+
+if ! iptables --version >/dev/null 2>&1; then
+	echo "SKIP: Test needs iptables"
+	exit $ksft_skip
+fi
+if ! ip -V >/dev/null 2>&1; then
+	echo "SKIP: Test needs iproute2"
+	exit $ksft_skip
+fi
+if ! nc -h >/dev/null 2>&1; then
+	echo "SKIP: Test needs netcat"
+	exit $ksft_skip
+fi
+
+pattern="foo bar baz"
+patlen=11
+hdrlen=$((20 + 8)) # IPv4 + UDP
+ns="ns-$(mktemp -u XXXXXXXX)"
+trap 'ip netns del $ns' EXIT
+ip netns add "$ns"
+ip -net "$ns" link add d0 type dummy
+ip -net "$ns" link set d0 up
+ip -net "$ns" addr add 10.1.2.1/24 dev d0
+
+#ip netns exec "$ns" tcpdump -npXi d0 &
+#tcpdump_pid=$!
+#trap 'kill $tcpdump_pid; ip netns del $ns' EXIT
+
+add_rule() { # (alg, from, to)
+	ip netns exec "$ns" \
+		iptables -A OUTPUT -o d0 -m string \
+			--string "$pattern" --algo $1 --from $2 --to $3
+}
+showrules() { # ()
+	ip netns exec "$ns" iptables -v -S OUTPUT | grep '^-A'
+}
+zerorules() {
+	ip netns exec "$ns" iptables -Z OUTPUT
+}
+countrule() { # (pattern)
+	showrules | grep -c -- "$*"
+}
+send() { # (offset)
+	( for ((i = 0; i < $1 - $hdrlen; i++)); do
+		printf " "
+	  done
+	  printf "$pattern"
+	) | ip netns exec "$ns" nc -w 1 -u 10.1.2.2 27374
+}
+
+add_rule bm 1000 1500
+add_rule bm 1400 1600
+add_rule kmp 1000 1500
+add_rule kmp 1400 1600
+
+zerorules
+send 0
+send $((1000 - $patlen))
+if [ $(countrule -c 0 0) -ne 4 ]; then
+	echo "FAIL: rules match data before --from"
+	showrules
+	((rc--))
+fi
+
+zerorules
+send 1000
+send $((1400 - $patlen))
+if [ $(countrule -c 2) -ne 2 ]; then
+	echo "FAIL: only two rules should match at low offset"
+	showrules
+	((rc--))
+fi
+
+zerorules
+send $((1500 - $patlen))
+if [ $(countrule -c 1) -ne 4 ]; then
+	echo "FAIL: all rules should match at end of packet"
+	showrules
+	((rc--))
+fi
+
+zerorules
+send 1495
+if [ $(countrule -c 1) -ne 1 ]; then
+	echo "FAIL: only kmp with proper --to should match pattern spanning fragments"
+	showrules
+	((rc--))
+fi
+
+zerorules
+send 1500
+if [ $(countrule -c 1) -ne 2 ]; then
+	echo "FAIL: two rules should match pattern at start of second fragment"
+	showrules
+	((rc--))
+fi
+
+zerorules
+send $((1600 - $patlen))
+if [ $(countrule -c 1) -ne 2 ]; then
+	echo "FAIL: two rules should match pattern at end of largest --to"
+	showrules
+	((rc--))
+fi
+
+zerorules
+send $((1600 - $patlen + 1))
+if [ $(countrule -c 1) -ne 0 ]; then
+	echo "FAIL: no rules should match pattern extending largest --to"
+	showrules
+	((rc--))
+fi
+
+zerorules
+send 1600
+if [ $(countrule -c 1) -ne 0 ]; then
+	echo "FAIL: no rule should match pattern past largest --to"
+	showrules
+	((rc--))
+fi
+
+exit $rc