selftests: netfilter: add nfqueue TCP_NEW_SYN_RECV socket race test

causes:
BUG: KASAN: slab-out-of-bounds in sk_free+0x25/0x80
Write of size 4 at addr ffff888106df0284 by task nf-queue/1459
 sk_free+0x25/0x80
 nf_queue_entry_release_refs+0x143/0x1a0
 nf_reinject+0x233/0x770

... without 'netfilter: nf_queue: don't assume sk is full socket'.
Signed-off-by: Florian Westphal <fw@strlen.de>

tools/testing/selftests/netfilter/.gitignore

 # SPDX-License-Identifier: GPL-2.0-only
 nf-queue
+connect_close

tools/testing/selftests/netfilter/Makefile

@@ -9,6 +9,6 @@ TEST_PROGS := nft_trans_stress.sh nft_fib.sh nft_nat.sh bridge_brouter.sh \
 	conntrack_vrf.sh nft_synproxy.sh
 
 LDLIBS = -lmnl
-TEST_GEN_FILES =  nf-queue
+TEST_GEN_FILES =  nf-queue connect_close
 
 include ../lib.mk

tools/testing/selftests/netfilter/connect_close.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#define PORT 12345
+#define RUNTIME 10
+
+static struct {
+	unsigned int timeout;
+	unsigned int port;
+} opts = {
+	.timeout = RUNTIME,
+	.port = PORT,
+};
+
+static void handler(int sig)
+{
+	_exit(sig == SIGALRM ? 0 : 1);
+}
+
+static void set_timeout(void)
+{
+	struct sigaction action = {
+		.sa_handler = handler,
+	};
+
+	sigaction(SIGALRM, &action, NULL);
+
+	alarm(opts.timeout);
+}
+
+static void do_connect(const struct sockaddr_in *dst)
+{
+	int s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+	if (s >= 0)
+		fcntl(s, F_SETFL, O_NONBLOCK);
+
+	connect(s, (struct sockaddr *)dst, sizeof(*dst));
+	close(s);
+}
+
+static void do_accept(const struct sockaddr_in *src)
+{
+	int c, one = 1, s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+	if (s < 0)
+		return;
+
+	setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+	setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+
+	bind(s, (struct sockaddr *)src, sizeof(*src));
+
+	listen(s, 16);
+
+	c = accept(s, NULL, NULL);
+	if (c >= 0)
+		close(c);
+
+	close(s);
+}
+
+static int accept_loop(void)
+{
+	struct sockaddr_in src = {
+		.sin_family = AF_INET,
+		.sin_port = htons(opts.port),
+	};
+
+	inet_pton(AF_INET, "127.0.0.1", &src.sin_addr);
+
+	set_timeout();
+
+	for (;;)
+		do_accept(&src);
+
+	return 1;
+}
+
+static int connect_loop(void)
+{
+	struct sockaddr_in dst = {
+		.sin_family = AF_INET,
+		.sin_port = htons(opts.port),
+	};
+
+	inet_pton(AF_INET, "127.0.0.1", &dst.sin_addr);
+
+	set_timeout();
+
+	for (;;)
+		do_connect(&dst);
+
+	return 1;
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "t:p:")) != -1) {
+		switch (c) {
+		case 't':
+			opts.timeout = atoi(optarg);
+			break;
+		case 'p':
+			opts.port = atoi(optarg);
+			break;
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	pid_t p;
+
+	parse_opts(argc, argv);
+
+	p = fork();
+	if (p < 0)
+		return 111;
+
+	if (p > 0)
+		return accept_loop();
+
+	return connect_loop();
+}

tools/testing/selftests/netfilter/nft_queue.sh

@@ -113,6 +113,7 @@ table inet $name {
 	chain output {
 		type filter hook output priority $prio; policy accept;
 		tcp dport 12345 queue num 3
+		tcp sport 23456 queue num 3
 		jump nfq
 	}
 	chain post {
@@ -296,6 +297,23 @@ test_tcp_localhost()
 	wait 2>/dev/null
 }
 
+test_tcp_localhost_connectclose()
+{
+	tmpfile=$(mktemp) || exit 1
+
+	ip netns exec ${nsrouter} ./connect_close -p 23456 -t $timeout &
+
+	ip netns exec ${nsrouter} ./nf-queue -q 3 -t $timeout &
+	local nfqpid=$!
+
+	sleep 1
+	rm -f "$tmpfile"
+
+	wait $rpid
+	[ $? -eq 0 ] && echo "PASS: tcp via loopback with connect/close"
+	wait 2>/dev/null
+}
+
 test_tcp_localhost_requeue()
 {
 ip netns exec ${nsrouter} nft -f /dev/stdin <<EOF
@@ -424,6 +442,7 @@ test_queue 20
 
 test_tcp_forward
 test_tcp_localhost
+test_tcp_localhost_connectclose
 test_tcp_localhost_requeue
 test_icmp_vrf