From 3f0a16b084df2939faf129a007f1cb3af34a67b9 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 24 Jun 2021 12:36:41 +0200 Subject: [PATCH] selftest: netfilter: add test case for unreplied tcp connections TCP connections in UNREPLIED state (only SYN seen) can be kept alive indefinitely, as each SYN re-sets the timeout. This means that even if a peer has closed its socket the entry never times out. This also prevents re-evaluation of configured NAT rules. Add a test case that sets SYN timeout to 10 seconds, then check that the nat redirection added later eventually takes effect. This is based off a repro script from Antonio Ojea. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- tools/testing/selftests/netfilter/Makefile | 2 +- .../netfilter/conntrack_tcp_unreplied.sh | 167 ++++++++++++++++++ 2 files changed, 168 insertions(+), 1 deletion(-) create mode 100755 tools/testing/selftests/netfilter/conntrack_tcp_unreplied.sh diff --git a/tools/testing/selftests/netfilter/Makefile b/tools/testing/selftests/netfilter/Makefile index cd6430b399820..8748199ac1098 100644 --- a/tools/testing/selftests/netfilter/Makefile +++ b/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 diff --git a/tools/testing/selftests/netfilter/conntrack_tcp_unreplied.sh b/tools/testing/selftests/netfilter/conntrack_tcp_unreplied.sh new file mode 100755 index 0000000000000..e7d7bf13cff53 --- /dev/null +++ b/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 - < $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 - </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 -- 2.39.5