selftests: add xfrm policy test script

add a script that adds a ipsec tunnel between two network
namespaces plus following policies:

.0/24 -> ipsec tunnel
.240/28 -> bypass
.253/32 -> ipsec tunnel

Then check that .254 bypasses tunnel (match /28 exception),
and .2 (match /24) and .253 (match direct policy) pass through the
tunnel.

Abuses iptables to check if ping did resolve an ipsec policy or not.

Also adds a bunch of 'block' rules that are not supposed to match.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

tools/testing/selftests/net/Makefile

@@ -4,7 +4,8 @@
 CFLAGS =  -Wall -Wl,--no-as-needed -O2 -g
 CFLAGS += -I../../../../usr/include/
 
-TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh rtnetlink.sh
+TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh \
+	      rtnetlink.sh xfrm_policy.sh
 TEST_PROGS += fib_tests.sh fib-onlink-tests.sh pmtu.sh udpgso.sh ip_defrag.sh
 TEST_PROGS += udpgso_bench.sh fib_rule_tests.sh msg_zerocopy.sh psock_snd.sh
 TEST_PROGS += udpgro_bench.sh udpgro.sh

tools/testing/selftests/net/xfrm_policy.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Check xfrm policy resolution.  Topology:
+#
+# 1.2   1.1   3.1  3.10    2.1   2.2
+# eth1  eth1 veth0 veth0 eth1   eth1
+# ns1 ---- ns3 ----- ns4 ---- ns2
+#
+# ns3 and ns4 are connected via ipsec tunnel.
+# pings from ns1 to ns2 (and vice versa) are supposed to work like this:
+# ns1: ping 10.0.2.2: passes via ipsec tunnel.
+# ns2: ping 10.0.1.2: passes via ipsec tunnel.
+
+# ns1: ping 10.0.1.253: passes via ipsec tunnel (direct policy)
+# ns2: ping 10.0.2.253: passes via ipsec tunnel (direct policy)
+#
+# ns1: ping 10.0.2.254: does NOT pass via ipsec tunnel (exception)
+# ns2: ping 10.0.1.254: does NOT pass via ipsec tunnel (exception)
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+ret=0
+
+KEY_SHA=0xdeadbeef1234567890abcdefabcdefabcdefabcd
+KEY_AES=0x0123456789abcdef0123456789012345
+SPI1=0x1
+SPI2=0x2
+
+do_esp() {
+    local ns=$1
+    local me=$2
+    local remote=$3
+    local lnet=$4
+    local rnet=$5
+    local spi_out=$6
+    local spi_in=$7
+
+    ip -net $ns xfrm state add src $remote dst $me proto esp spi $spi_in  enc aes $KEY_AES  auth sha1 $KEY_SHA  mode tunnel sel src $rnet dst $lnet
+    ip -net $ns xfrm state add src $me  dst $remote proto esp spi $spi_out enc aes $KEY_AES auth sha1 $KEY_SHA mode tunnel sel src $lnet dst $rnet
+
+    # to encrypt packets as they go out (includes forwarded packets that need encapsulation)
+    ip -net $ns xfrm policy add src $lnet dst $rnet dir out tmpl src $me dst $remote proto esp mode tunnel priority 100 action allow
+    # to fwd decrypted packets after esp processing:
+    ip -net $ns xfrm policy add src $rnet dst $lnet dir fwd tmpl src $remote dst $me proto esp mode tunnel priority 100 action allow
+}
+
+do_exception() {
+    local ns=$1
+    local me=$2
+    local remote=$3
+    local encryptip=$4
+    local plain=$5
+
+    # network $plain passes without tunnel
+    ip -net $ns xfrm policy add dst $plain dir out priority 10 action allow
+
+    # direct policy for $encryptip, use tunnel, higher prio takes precedence
+    ip -net $ns xfrm policy add dst $encryptip dir out tmpl src $me dst $remote proto esp mode tunnel priority 1 action allow
+}
+
+# policies that are not supposed to match any packets generated in this test.
+do_dummies4() {
+    local ns=$1
+
+    for i in $(seq 10 16);do
+      # dummy policy with wildcard src/dst.
+      echo netns exec $ns ip xfrm policy add src 0.0.0.0/0 dst 10.$i.99.0/30 dir out action block
+      echo netns exec $ns ip xfrm policy add src 10.$i.99.0/30 dst 0.0.0.0/0 dir out action block
+      for j in $(seq 32 64);do
+        echo netns exec $ns ip xfrm policy add src 10.$i.1.0/30 dst 10.$i.$j.0/30 dir out action block
+        # silly, as it encompasses the one above too, but its allowed:
+        echo netns exec $ns ip xfrm policy add src 10.$i.1.0/29 dst 10.$i.$j.0/29 dir out action block
+        # and yet again, even more broad one.
+        echo netns exec $ns ip xfrm policy add src 10.$i.1.0/24 dst 10.$i.$j.0/24 dir out action block
+        echo netns exec $ns ip xfrm policy add src 10.$i.$j.0/24 dst 10.$i.1.0/24 dir fwd action block
+      done
+    done | ip -batch /dev/stdin
+}
+
+do_dummies6() {
+    local ns=$1
+
+    for i in $(seq 10 16);do
+      for j in $(seq 32 64);do
+       echo netns exec $ns ip xfrm policy add src dead:$i::/64 dst dead:$i:$j::/64 dir out action block
+       echo netns exec $ns ip xfrm policy add src dead:$i:$j::/64 dst dead:$i::/24 dir fwd action block
+      done
+    done | ip -batch /dev/stdin
+}
+
+check_ipt_policy_count()
+{
+	ns=$1
+
+	ip netns exec $ns iptables-save -c |grep policy | ( read c rest
+		ip netns exec $ns iptables -Z
+		if [ x"$c" = x'[0:0]' ]; then
+			exit 0
+		elif [ x"$c" = x ]; then
+			echo "ERROR: No counters"
+			ret=1
+			exit 111
+		else
+			exit 1
+		fi
+	)
+}
+
+check_xfrm() {
+	# 0: iptables -m policy rule count == 0
+	# 1: iptables -m policy rule count != 0
+	rval=$1
+	ip=$2
+	ret=0
+
+	ip netns exec ns1 ping -q -c 1 10.0.2.$ip > /dev/null
+
+	check_ipt_policy_count ns3
+	if [ $? -ne $rval ] ; then
+		ret=1
+	fi
+	check_ipt_policy_count ns4
+	if [ $? -ne $rval ] ; then
+		ret=1
+	fi
+
+	ip netns exec ns2 ping -q -c 1 10.0.1.$ip > /dev/null
+
+	check_ipt_policy_count ns3
+	if [ $? -ne $rval ] ; then
+		ret=1
+	fi
+	check_ipt_policy_count ns4
+	if [ $? -ne $rval ] ; then
+		ret=1
+	fi
+
+	return $ret
+}
+
+#check for needed privileges
+if [ "$(id -u)" -ne 0 ];then
+	echo "SKIP: Need root privileges"
+	exit $ksft_skip
+fi
+
+ip -Version 2>/dev/null >/dev/null
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not run test without the ip tool"
+	exit $ksft_skip
+fi
+
+# needed to check if policy lookup got valid ipsec result
+iptables --version 2>/dev/null >/dev/null
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not run test without iptables tool"
+	exit $ksft_skip
+fi
+
+for i in 1 2 3 4; do
+    ip netns add ns$i
+    ip -net ns$i link set lo up
+done
+
+DEV=veth0
+ip link add $DEV netns ns1 type veth peer name eth1 netns ns3
+ip link add $DEV netns ns2 type veth peer name eth1 netns ns4
+
+ip link add $DEV netns ns3 type veth peer name veth0 netns ns4
+
+DEV=veth0
+for i in 1 2; do
+    ip -net ns$i link set $DEV up
+    ip -net ns$i addr add 10.0.$i.2/24 dev $DEV
+    ip -net ns$i addr add dead:$i::2/64 dev $DEV
+
+    ip -net ns$i addr add 10.0.$i.253 dev $DEV
+    ip -net ns$i addr add 10.0.$i.254 dev $DEV
+    ip -net ns$i addr add dead:$i::fd dev $DEV
+    ip -net ns$i addr add dead:$i::fe dev $DEV
+done
+
+for i in 3 4; do
+ip -net ns$i link set eth1 up
+ip -net ns$i link set veth0 up
+done
+
+ip -net ns1 route add default via 10.0.1.1
+ip -net ns2 route add default via 10.0.2.1
+
+ip -net ns3 addr add 10.0.1.1/24 dev eth1
+ip -net ns3 addr add 10.0.3.1/24 dev veth0
+ip -net ns3 addr add 2001:1::1/64 dev eth1
+ip -net ns3 addr add 2001:3::1/64 dev veth0
+
+ip -net ns3 route add default via 10.0.3.10
+
+ip -net ns4 addr add 10.0.2.1/24 dev eth1
+ip -net ns4 addr add 10.0.3.10/24 dev veth0
+ip -net ns4 addr add 2001:2::1/64 dev eth1
+ip -net ns4 addr add 2001:3::10/64 dev veth0
+ip -net ns4 route add default via 10.0.3.1
+
+for j in 4 6; do
+	for i in 3 4;do
+		ip netns exec ns$i sysctl net.ipv$j.conf.eth1.forwarding=1 > /dev/null
+		ip netns exec ns$i sysctl net.ipv$j.conf.veth0.forwarding=1 > /dev/null
+	done
+done
+
+# abuse iptables rule counter to check if ping matches a policy
+ip netns exec ns3 iptables -p icmp -A FORWARD -m policy --dir out --pol ipsec
+ip netns exec ns4 iptables -p icmp -A FORWARD -m policy --dir out --pol ipsec
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not insert iptables rule"
+	for i in 1 2 3 4;do ip netns del ns$i;done
+	exit $ksft_skip
+fi
+
+#          localip  remoteip  localnet    remotenet
+do_esp ns3 10.0.3.1 10.0.3.10 10.0.1.0/24 10.0.2.0/24 $SPI1 $SPI2
+do_esp ns3 dead:3::1 dead:3::10 dead:1::/64 dead:2::/64 $SPI1 $SPI2
+do_esp ns4 10.0.3.10 10.0.3.1 10.0.2.0/24 10.0.1.0/24 $SPI2 $SPI1
+do_esp ns4 dead:3::10 dead:3::1 dead:2::/64 dead:1::/64 $SPI2 $SPI1
+
+do_dummies4 ns3
+do_dummies6 ns4
+
+# ping to .254 should use ipsec, exception is not installed.
+check_xfrm 1 254
+if [ $? -ne 0 ]; then
+	echo "FAIL: expected ping to .254 to use ipsec tunnel"
+	ret=1
+else
+	echo "PASS: policy before exception matches"
+fi
+
+# installs exceptions
+#                localip  remoteip   encryptdst  plaindst
+do_exception ns3 10.0.3.1 10.0.3.10 10.0.2.253 10.0.2.240/28
+do_exception ns4 10.0.3.10 10.0.3.1 10.0.1.253 10.0.1.240/28
+
+do_exception ns3 dead:3::1 dead:3::10 dead:2::fd  dead:2:f0::/96
+do_exception ns4 dead:3::10 dead:3::1 dead:1::fd  dead:1:f0::/96
+
+# ping to .254 should now be excluded from the tunnel
+check_xfrm 0 254
+if [ $? -ne 0 ]; then
+	echo "FAIL: expected ping to .254 to fail"
+	ret=1
+else
+	echo "PASS: ping to .254 bypassed ipsec tunnel"
+fi
+
+# ping to .253 should use use ipsec due to direct policy exception.
+check_xfrm 1 253
+if [ $? -ne 0 ]; then
+	echo "FAIL: expected ping to .253 to use ipsec tunnel"
+	ret=1
+else
+	echo "PASS: direct policy matches"
+fi
+
+# ping to .2 should use ipsec.
+check_xfrm 1 2
+if [ $? -ne 0 ]; then
+	echo "FAIL: expected ping to .2 to use ipsec tunnel"
+	ret=1
+else
+	echo "PASS: policy matches"
+fi
+
+for i in 1 2 3 4;do ip netns del ns$i;done
+
+exit $ret