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tailscale/util/linuxfw/iptables_runner_test.go

421 lines
12 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build linux
package linuxfw
import (
"errors"
"net/netip"
"strings"
"testing"
"tailscale.com/net/tsaddr"
)
var errExec = errors.New("execution failed")
type fakeIPTables struct {
t *testing.T
n map[string][]string
}
type fakeRule struct {
table, chain string
args []string
}
func newIPTables(t *testing.T) *fakeIPTables {
return &fakeIPTables{
t: t,
n: map[string][]string{
"filter/INPUT": nil,
"filter/OUTPUT": nil,
"filter/FORWARD": nil,
"nat/PREROUTING": nil,
"nat/OUTPUT": nil,
"nat/POSTROUTING": nil,
},
}
}
func (n *fakeIPTables) Insert(table, chain string, pos int, args ...string) error {
k := table + "/" + chain
if rules, ok := n.n[k]; ok {
if pos > len(rules)+1 {
n.t.Errorf("bad position %d in %s", pos, k)
return errExec
}
rules = append(rules, "")
copy(rules[pos:], rules[pos-1:])
rules[pos-1] = strings.Join(args, " ")
n.n[k] = rules
} else {
n.t.Errorf("unknown table/chain %s", k)
return errExec
}
return nil
}
func (n *fakeIPTables) Append(table, chain string, args ...string) error {
k := table + "/" + chain
return n.Insert(table, chain, len(n.n[k])+1, args...)
}
func (n *fakeIPTables) Exists(table, chain string, args ...string) (bool, error) {
k := table + "/" + chain
if rules, ok := n.n[k]; ok {
for _, rule := range rules {
if rule == strings.Join(args, " ") {
return true, nil
}
}
return false, nil
} else {
n.t.Logf("unknown table/chain %s", k)
return false, errExec
}
}
func hasChain(n *fakeIPTables, table, chain string) bool {
k := table + "/" + chain
if _, ok := n.n[k]; ok {
return true
} else {
return false
}
}
func (n *fakeIPTables) Delete(table, chain string, args ...string) error {
k := table + "/" + chain
if rules, ok := n.n[k]; ok {
for i, rule := range rules {
if rule == strings.Join(args, " ") {
rules = append(rules[:i], rules[i+1:]...)
n.n[k] = rules
return nil
}
}
n.t.Errorf("delete of unknown rule %q from %s", strings.Join(args, " "), k)
return errExec
} else {
n.t.Errorf("unknown table/chain %s", k)
return errExec
}
}
func (n *fakeIPTables) ClearChain(table, chain string) error {
k := table + "/" + chain
if _, ok := n.n[k]; ok {
n.n[k] = nil
return nil
} else {
n.t.Logf("note: ClearChain: unknown table/chain %s", k)
return errors.New("exitcode:1")
}
}
func (n *fakeIPTables) NewChain(table, chain string) error {
k := table + "/" + chain
if _, ok := n.n[k]; ok {
n.t.Errorf("table/chain %s already exists", k)
return errExec
}
n.n[k] = nil
return nil
}
func (n *fakeIPTables) DeleteChain(table, chain string) error {
k := table + "/" + chain
if rules, ok := n.n[k]; ok {
if len(rules) != 0 {
n.t.Errorf("%s is not empty", k)
return errExec
}
delete(n.n, k)
return nil
} else {
n.t.Errorf("%s does not exist", k)
return errExec
}
}
func newFakeIPTablesRunner(t *testing.T) *iptablesRunner {
ipt4 := newIPTables(t)
ipt6 := newIPTables(t)
iptr := &iptablesRunner{ipt4, ipt6, true, true}
return iptr
}
func TestAddAndDeleteChains(t *testing.T) {
iptr := newFakeIPTablesRunner(t)
err := iptr.AddChains()
if err != nil {
t.Fatal(err)
}
// Check that the chains were created.
tsChains := []struct{ table, chain string }{ // table/chain
{"filter", "ts-input"},
{"filter", "ts-forward"},
{"nat", "ts-postrouting"},
}
for _, proto := range []iptablesInterface{iptr.ipt4, iptr.ipt6} {
for _, tc := range tsChains {
// Exists returns error if the chain doesn't exist.
if _, err := proto.Exists(tc.table, tc.chain); err != nil {
t.Errorf("chain %s/%s doesn't exist", tc.table, tc.chain)
}
}
}
err = iptr.DelChains()
if err != nil {
t.Fatal(err)
}
// Check that the chains were deleted.
for _, proto := range []iptablesInterface{iptr.ipt4, iptr.ipt6} {
for _, tc := range tsChains {
if _, err = proto.Exists(tc.table, tc.chain); err == nil {
t.Errorf("chain %s/%s still exists", tc.table, tc.chain)
}
}
}
}
func TestAddAndDeleteHooks(t *testing.T) {
iptr := newFakeIPTablesRunner(t)
// don't need to test what happens if the chains don't exist, because
// this is handled by fake iptables, in realife iptables would return error.
if err := iptr.AddChains(); err != nil {
t.Fatal(err)
}
defer iptr.DelChains()
if err := iptr.AddHooks(); err != nil {
t.Fatal(err)
}
// Check that the rules were created.
tsRules := []fakeRule{ // table/chain/rule
{"filter", "INPUT", []string{"-j", "ts-input"}},
{"filter", "FORWARD", []string{"-j", "ts-forward"}},
{"nat", "POSTROUTING", []string{"-j", "ts-postrouting"}},
}
for _, proto := range []iptablesInterface{iptr.ipt4, iptr.ipt6} {
for _, tr := range tsRules {
if exists, err := proto.Exists(tr.table, tr.chain, tr.args...); err != nil {
t.Fatal(err)
} else if !exists {
t.Errorf("rule %s/%s/%s doesn't exist", tr.table, tr.chain, strings.Join(tr.args, " "))
}
// check if the rule is at front of the chain
if proto.(*fakeIPTables).n[tr.table+"/"+tr.chain][0] != strings.Join(tr.args, " ") {
t.Errorf("v4 rule %s/%s/%s is not at the top", tr.table, tr.chain, strings.Join(tr.args, " "))
}
}
}
if err := iptr.DelHooks(t.Logf); err != nil {
t.Fatal(err)
}
// Check that the rules were deleted.
for _, proto := range []iptablesInterface{iptr.ipt4, iptr.ipt6} {
for _, tr := range tsRules {
if exists, err := proto.Exists(tr.table, tr.chain, tr.args...); err != nil {
t.Fatal(err)
} else if exists {
t.Errorf("rule %s/%s/%s still exists", tr.table, tr.chain, strings.Join(tr.args, " "))
}
}
}
if err := iptr.AddHooks(); err != nil {
t.Fatal(err)
}
}
func TestAddAndDeleteBase(t *testing.T) {
iptr := newFakeIPTablesRunner(t)
tunname := "tun0"
if err := iptr.AddChains(); err != nil {
t.Fatal(err)
}
if err := iptr.AddBase(tunname); err != nil {
t.Fatal(err)
}
// Check that the rules were created.
tsRulesV4 := []fakeRule{ // table/chain/rule
{"filter", "ts-input", []string{"!", "-i", tunname, "-s", tsaddr.ChromeOSVMRange().String(), "-j", "RETURN"}},
{"filter", "ts-input", []string{"!", "-i", tunname, "-s", tsaddr.CGNATRange().String(), "-j", "DROP"}},
{"filter", "ts-forward", []string{"-o", tunname, "-s", tsaddr.CGNATRange().String(), "-j", "DROP"}},
}
tsRulesCommon := []fakeRule{ // table/chain/rule
{"filter", "ts-forward", []string{"-i", tunname, "-j", "MARK", "--set-mark", TailscaleSubnetRouteMark + "/" + TailscaleFwmarkMask}},
{"filter", "ts-forward", []string{"-m", "mark", "--mark", TailscaleSubnetRouteMark + "/" + TailscaleFwmarkMask, "-j", "ACCEPT"}},
{"filter", "ts-forward", []string{"-o", tunname, "-j", "ACCEPT"}},
}
// check that the rules were created for ipt4
for _, tr := range append(tsRulesV4, tsRulesCommon...) {
if exists, err := iptr.ipt4.Exists(tr.table, tr.chain, tr.args...); err != nil {
t.Fatal(err)
} else if !exists {
t.Errorf("rule %s/%s/%s doesn't exist", tr.table, tr.chain, strings.Join(tr.args, " "))
}
}
// check that the rules were created for ipt6
for _, tr := range tsRulesCommon {
if exists, err := iptr.ipt6.Exists(tr.table, tr.chain, tr.args...); err != nil {
t.Fatal(err)
} else if !exists {
t.Errorf("rule %s/%s/%s doesn't exist", tr.table, tr.chain, strings.Join(tr.args, " "))
}
}
if err := iptr.DelBase(); err != nil {
t.Fatal(err)
}
// Check that the rules were deleted.
for _, proto := range []iptablesInterface{iptr.ipt4, iptr.ipt6} {
for _, tr := range append(tsRulesV4, tsRulesCommon...) {
if exists, err := proto.Exists(tr.table, tr.chain, tr.args...); err != nil {
t.Fatal(err)
} else if exists {
t.Errorf("rule %s/%s/%s still exists", tr.table, tr.chain, strings.Join(tr.args, " "))
}
}
}
if err := iptr.DelChains(); err != nil {
t.Fatal(err)
}
}
func TestAddAndDelLoopbackRule(t *testing.T) {
iptr := newFakeIPTablesRunner(t)
// We don't need to test for malformed addresses, AddLoopbackRule
// takes in a netip.Addr, which is already valid.
fakeAddrV4 := netip.MustParseAddr("192.168.0.2")
fakeAddrV6 := netip.MustParseAddr("2001:db8::2")
if err := iptr.AddChains(); err != nil {
t.Fatal(err)
}
if err := iptr.AddLoopbackRule(fakeAddrV4); err != nil {
t.Fatal(err)
}
if err := iptr.AddLoopbackRule(fakeAddrV6); err != nil {
t.Fatal(err)
}
// Check that the rules were created.
tsRulesV4 := fakeRule{ // table/chain/rule
"filter", "ts-input", []string{"-i", "lo", "-s", fakeAddrV4.String(), "-j", "ACCEPT"}}
tsRulesV6 := fakeRule{ // table/chain/rule
"filter", "ts-input", []string{"-i", "lo", "-s", fakeAddrV6.String(), "-j", "ACCEPT"}}
// check that the rules were created for ipt4 and ipt6
if exist, err := iptr.ipt4.Exists(tsRulesV4.table, tsRulesV4.chain, tsRulesV4.args...); err != nil {
t.Fatal(err)
} else if !exist {
t.Errorf("rule %s/%s/%s doesn't exist", tsRulesV4.table, tsRulesV4.chain, strings.Join(tsRulesV4.args, " "))
}
if exist, err := iptr.ipt6.Exists(tsRulesV6.table, tsRulesV6.chain, tsRulesV6.args...); err != nil {
t.Fatal(err)
} else if !exist {
t.Errorf("rule %s/%s/%s doesn't exist", tsRulesV6.table, tsRulesV6.chain, strings.Join(tsRulesV6.args, " "))
}
// check that the rule is at the top
chain := "filter/ts-input"
if iptr.ipt4.(*fakeIPTables).n[chain][0] != strings.Join(tsRulesV4.args, " ") {
t.Errorf("v4 rule %s/%s/%s is not at the top", tsRulesV4.table, tsRulesV4.chain, strings.Join(tsRulesV4.args, " "))
}
if iptr.ipt6.(*fakeIPTables).n[chain][0] != strings.Join(tsRulesV6.args, " ") {
t.Errorf("v6 rule %s/%s/%s is not at the top", tsRulesV6.table, tsRulesV6.chain, strings.Join(tsRulesV6.args, " "))
}
// delete the rules
if err := iptr.DelLoopbackRule(fakeAddrV4); err != nil {
t.Fatal(err)
}
if err := iptr.DelLoopbackRule(fakeAddrV6); err != nil {
t.Fatal(err)
}
// Check that the rules were deleted.
if exist, err := iptr.ipt4.Exists(tsRulesV4.table, tsRulesV4.chain, tsRulesV4.args...); err != nil {
t.Fatal(err)
} else if exist {
t.Errorf("rule %s/%s/%s still exists", tsRulesV4.table, tsRulesV4.chain, strings.Join(tsRulesV4.args, " "))
}
if exist, err := iptr.ipt6.Exists(tsRulesV6.table, tsRulesV6.chain, tsRulesV6.args...); err != nil {
t.Fatal(err)
} else if exist {
t.Errorf("rule %s/%s/%s still exists", tsRulesV6.table, tsRulesV6.chain, strings.Join(tsRulesV6.args, " "))
}
if err := iptr.DelChains(); err != nil {
t.Fatal(err)
}
}
func TestAddAndDelSNATRule(t *testing.T) {
iptr := newFakeIPTablesRunner(t)
if err := iptr.AddChains(); err != nil {
t.Fatal(err)
}
rule := fakeRule{ // table/chain/rule
"nat", "ts-postrouting", []string{"-m", "mark", "--mark", TailscaleSubnetRouteMark + "/" + TailscaleFwmarkMask, "-j", "MASQUERADE"},
}
// Add SNAT rule
if err := iptr.AddSNATRule(); err != nil {
t.Fatal(err)
}
// Check that the rule was created for ipt4 and ipt6
for _, proto := range []iptablesInterface{iptr.ipt4, iptr.ipt6} {
if exist, err := proto.Exists(rule.table, rule.chain, rule.args...); err != nil {
t.Fatal(err)
} else if !exist {
t.Errorf("rule %s/%s/%s doesn't exist", rule.table, rule.chain, strings.Join(rule.args, " "))
}
}
// Delete SNAT rule
if err := iptr.DelSNATRule(); err != nil {
t.Fatal(err)
}
// Check that the rule was deleted for ipt4 and ipt6
for _, proto := range []iptablesInterface{iptr.ipt4, iptr.ipt6} {
if exist, err := proto.Exists(rule.table, rule.chain, rule.args...); err != nil {
t.Fatal(err)
} else if exist {
t.Errorf("rule %s/%s/%s still exists", rule.table, rule.chain, strings.Join(rule.args, " "))
}
}
if err := iptr.DelChains(); err != nil {
t.Fatal(err)
}
}