containernetworking-plugins/plugins/meta/firewall/firewall_iptables_test.go
Tim Gross 58dd90b996 ensure iptables chain creation is idempotent
Concurrent use of the `portmap` and `firewall` plugins can result in
errors during iptables chain creation:

- The `portmap` plugin has a time-of-check-time-of-use race where it
  checks for existence of the chain but the operation isn't atomic.
- The `firewall` plugin doesn't check for existing chains and just
  returns an error.

This commit makes both operations idempotent by creating the chain and
then discarding the error if it's caused by the chain already
existing. It also factors the chain creation out into `pkg/utils` as a
site for future refactoring work.

Signed-off-by: Tim Gross <tim@0x74696d.com>
2019-11-11 10:00:11 -05:00

520 lines
13 KiB
Go

// Copyright 2017 CNI authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"encoding/json"
"fmt"
"strings"
"github.com/containernetworking/cni/pkg/skel"
"github.com/containernetworking/cni/pkg/types"
"github.com/containernetworking/cni/pkg/types/current"
"github.com/containernetworking/cni/pkg/version"
"github.com/containernetworking/plugins/pkg/ns"
"github.com/containernetworking/plugins/pkg/testutils"
"github.com/vishvananda/netlink"
"github.com/coreos/go-iptables/iptables"
. "github.com/onsi/ginkgo"
. "github.com/onsi/gomega"
)
func findChains(chains []string) (bool, bool) {
var foundAdmin, foundPriv bool
for _, ch := range chains {
if ch == "CNI-ADMIN" {
foundAdmin = true
} else if ch == "CNI-FORWARD" {
foundPriv = true
}
}
return foundAdmin, foundPriv
}
func findForwardJumpRules(rules []string) (bool, bool) {
var foundAdmin, foundPriv bool
for _, rule := range rules {
if strings.Contains(rule, "-j CNI-ADMIN") {
foundAdmin = true
} else if strings.Contains(rule, "-j CNI-FORWARD") {
foundPriv = true
}
}
return foundAdmin, foundPriv
}
func findForwardAllowRules(rules []string, ip string) (bool, bool) {
var foundOne, foundTwo bool
for _, rule := range rules {
if !strings.HasSuffix(rule, "-j ACCEPT") {
continue
}
if strings.Contains(rule, fmt.Sprintf(" -s %s ", ip)) {
foundOne = true
} else if strings.Contains(rule, fmt.Sprintf(" -d %s ", ip)) && strings.Contains(rule, "RELATED,ESTABLISHED") {
foundTwo = true
}
}
return foundOne, foundTwo
}
func getPrevResult(bytes []byte) *current.Result {
type TmpConf struct {
types.NetConf
RawPrevResult map[string]interface{} `json:"prevResult,omitempty"`
PrevResult *current.Result `json:"-"`
}
conf := &TmpConf{}
err := json.Unmarshal(bytes, conf)
Expect(err).NotTo(HaveOccurred())
if conf.RawPrevResult == nil {
return nil
}
resultBytes, err := json.Marshal(conf.RawPrevResult)
Expect(err).NotTo(HaveOccurred())
res, err := version.NewResult(conf.CNIVersion, resultBytes)
Expect(err).NotTo(HaveOccurred())
prevResult, err := current.NewResultFromResult(res)
Expect(err).NotTo(HaveOccurred())
return prevResult
}
func validateFullRuleset(bytes []byte) {
prevResult := getPrevResult(bytes)
for _, ip := range prevResult.IPs {
ipt, err := iptables.NewWithProtocol(protoForIP(ip.Address))
Expect(err).NotTo(HaveOccurred())
// Ensure chains
chains, err := ipt.ListChains("filter")
Expect(err).NotTo(HaveOccurred())
foundAdmin, foundPriv := findChains(chains)
Expect(foundAdmin).To(Equal(true))
Expect(foundPriv).To(Equal(true))
// Look for the FORWARD chain jump rules to our custom chains
rules, err := ipt.List("filter", "FORWARD")
Expect(err).NotTo(HaveOccurred())
Expect(len(rules)).Should(BeNumerically(">", 1))
_, foundPriv = findForwardJumpRules(rules)
Expect(foundPriv).To(Equal(true))
// Look for the allow rules in our custom FORWARD chain
rules, err = ipt.List("filter", "CNI-FORWARD")
Expect(err).NotTo(HaveOccurred())
Expect(len(rules)).Should(BeNumerically(">", 1))
foundAdmin, _ = findForwardJumpRules(rules)
Expect(foundAdmin).To(Equal(true))
// Look for the IP allow rules
foundOne, foundTwo := findForwardAllowRules(rules, ipString(ip.Address))
Expect(foundOne).To(Equal(true))
Expect(foundTwo).To(Equal(true))
}
}
func validateCleanedUp(bytes []byte) {
prevResult := getPrevResult(bytes)
for _, ip := range prevResult.IPs {
ipt, err := iptables.NewWithProtocol(protoForIP(ip.Address))
Expect(err).NotTo(HaveOccurred())
// Our private and admin chains don't get cleaned up
chains, err := ipt.ListChains("filter")
Expect(err).NotTo(HaveOccurred())
foundAdmin, foundPriv := findChains(chains)
Expect(foundAdmin).To(Equal(true))
Expect(foundPriv).To(Equal(true))
// Look for the FORWARD chain jump rules to our custom chains
rules, err := ipt.List("filter", "FORWARD")
Expect(err).NotTo(HaveOccurred())
_, foundPriv = findForwardJumpRules(rules)
Expect(foundPriv).To(Equal(true))
// Look for the allow rules in our custom FORWARD chain
rules, err = ipt.List("filter", "CNI-FORWARD")
Expect(err).NotTo(HaveOccurred())
foundAdmin, _ = findForwardJumpRules(rules)
Expect(foundAdmin).To(Equal(true))
// Expect no IP address rules for this IP
foundOne, foundTwo := findForwardAllowRules(rules, ipString(ip.Address))
Expect(foundOne).To(Equal(false))
Expect(foundTwo).To(Equal(false))
}
}
var _ = Describe("firewall plugin iptables backend", func() {
var originalNS, targetNS ns.NetNS
const IFNAME string = "dummy0"
fullConf := []byte(`{
"name": "test",
"type": "firewall",
"backend": "iptables",
"ifName": "dummy0",
"cniVersion": "0.3.1",
"prevResult": {
"interfaces": [
{"name": "dummy0"}
],
"ips": [
{
"version": "4",
"address": "10.0.0.2/24",
"interface": 0
},
{
"version": "6",
"address": "2001:db8:1:2::1/64",
"interface": 0
}
]
}
}`)
BeforeEach(func() {
// Create a new NetNS so we don't modify the host
var err error
originalNS, err = testutils.NewNS()
Expect(err).NotTo(HaveOccurred())
err = originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
err = netlink.LinkAdd(&netlink.Dummy{
LinkAttrs: netlink.LinkAttrs{
Name: IFNAME,
},
})
Expect(err).NotTo(HaveOccurred())
_, err = netlink.LinkByName(IFNAME)
Expect(err).NotTo(HaveOccurred())
return nil
})
Expect(err).NotTo(HaveOccurred())
targetNS, err = testutils.NewNS()
Expect(err).NotTo(HaveOccurred())
})
AfterEach(func() {
Expect(originalNS.Close()).To(Succeed())
Expect(targetNS.Close()).To(Succeed())
})
It("passes prevResult through unchanged", func() {
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: IFNAME,
StdinData: fullConf,
}
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
r, _, err := testutils.CmdAdd(targetNS.Path(), args.ContainerID, IFNAME, fullConf, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
result, err := current.GetResult(r)
Expect(err).NotTo(HaveOccurred())
Expect(len(result.Interfaces)).To(Equal(1))
Expect(result.Interfaces[0].Name).To(Equal(IFNAME))
Expect(len(result.IPs)).To(Equal(2))
Expect(result.IPs[0].Address.String()).To(Equal("10.0.0.2/24"))
Expect(result.IPs[1].Address.String()).To(Equal("2001:db8:1:2::1/64"))
return nil
})
Expect(err).NotTo(HaveOccurred())
})
It("installs the right iptables rules on the host", func() {
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: IFNAME,
StdinData: fullConf,
}
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
_, _, err := testutils.CmdAdd(targetNS.Path(), args.ContainerID, IFNAME, fullConf, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
validateFullRuleset(fullConf)
// ensure creation is idempotent
_, _, err = testutils.CmdAdd(targetNS.Path(), args.ContainerID, IFNAME, fullConf, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
return nil
})
Expect(err).NotTo(HaveOccurred())
})
It("correctly handles a custom IptablesAdminChainName", func() {
conf := []byte(`{
"name": "test",
"type": "firewall",
"backend": "iptables",
"ifName": "dummy0",
"cniVersion": "0.3.1",
"iptablesAdminChainName": "CNI-foobar",
"prevResult": {
"interfaces": [
{"name": "dummy0"}
],
"ips": [
{
"version": "4",
"address": "10.0.0.2/24",
"interface": 0
},
{
"version": "6",
"address": "2001:db8:1:2::1/64",
"interface": 0
}
]
}
}`)
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: IFNAME,
StdinData: conf,
}
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
_, _, err := testutils.CmdAdd(targetNS.Path(), args.ContainerID, IFNAME, conf, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
var ipt *iptables.IPTables
for _, proto := range []iptables.Protocol{iptables.ProtocolIPv4, iptables.ProtocolIPv6} {
ipt, err = iptables.NewWithProtocol(proto)
Expect(err).NotTo(HaveOccurred())
// Ensure custom admin chain name
chains, err := ipt.ListChains("filter")
Expect(err).NotTo(HaveOccurred())
var foundAdmin bool
for _, ch := range chains {
if ch == "CNI-foobar" {
foundAdmin = true
}
}
Expect(foundAdmin).To(Equal(true))
}
return nil
})
Expect(err).NotTo(HaveOccurred())
})
It("cleans up on delete", func() {
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: IFNAME,
StdinData: fullConf,
}
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
_, _, err := testutils.CmdAdd(targetNS.Path(), args.ContainerID, IFNAME, fullConf, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
validateFullRuleset(fullConf)
err = testutils.CmdDel(targetNS.Path(), args.ContainerID, IFNAME, func() error {
return cmdDel(args)
})
Expect(err).NotTo(HaveOccurred())
validateCleanedUp(fullConf)
return nil
})
Expect(err).NotTo(HaveOccurred())
})
It("installs the right iptables rules on the host v4.0.x and check is successful", func() {
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: IFNAME,
StdinData: fullConf,
}
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
_, _, err := testutils.CmdAdd(targetNS.Path(), args.ContainerID, IFNAME, fullConf, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
validateFullRuleset(fullConf)
return nil
})
Expect(err).NotTo(HaveOccurred())
})
It("cleans up on delete v4.0.x", func() {
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: IFNAME,
StdinData: fullConf,
}
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
_, _, err := testutils.CmdAdd(targetNS.Path(), args.ContainerID, IFNAME, fullConf, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
validateFullRuleset(fullConf)
err = testutils.CmdDel(targetNS.Path(), args.ContainerID, IFNAME, func() error {
return cmdDel(args)
})
Expect(err).NotTo(HaveOccurred())
validateCleanedUp(fullConf)
return nil
})
Expect(err).NotTo(HaveOccurred())
})
})
var _ = Describe("firewall plugin iptables backend v0.4.x", func() {
var originalNS, targetNS ns.NetNS
const IFNAME string = "dummy0"
fullConf := []byte(`{
"name": "test",
"type": "firewall",
"backend": "iptables",
"ifName": "dummy0",
"cniVersion": "0.4.0",
"prevResult": {
"interfaces": [
{"name": "dummy0"}
],
"ips": [
{
"version": "4",
"address": "10.0.0.2/24",
"interface": 0
},
{
"version": "6",
"address": "2001:db8:1:2::1/64",
"interface": 0
}
]
}
}`)
BeforeEach(func() {
// Create a new NetNS so we don't modify the host
var err error
originalNS, err = testutils.NewNS()
Expect(err).NotTo(HaveOccurred())
err = originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
err = netlink.LinkAdd(&netlink.Dummy{
LinkAttrs: netlink.LinkAttrs{
Name: IFNAME,
},
})
Expect(err).NotTo(HaveOccurred())
_, err = netlink.LinkByName(IFNAME)
Expect(err).NotTo(HaveOccurred())
return nil
})
Expect(err).NotTo(HaveOccurred())
targetNS, err = testutils.NewNS()
Expect(err).NotTo(HaveOccurred())
})
AfterEach(func() {
Expect(originalNS.Close()).To(Succeed())
Expect(targetNS.Close()).To(Succeed())
})
It("installs iptables rules, Check rules then cleans up on delete using v4.0.x", func() {
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: IFNAME,
StdinData: fullConf,
}
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
r, _, err := testutils.CmdAddWithArgs(args, func() error {
return cmdAdd(args)
})
Expect(err).NotTo(HaveOccurred())
_, err = current.GetResult(r)
Expect(err).NotTo(HaveOccurred())
err = testutils.CmdCheckWithArgs(args, func() error {
return cmdCheck(args)
})
Expect(err).NotTo(HaveOccurred())
validateFullRuleset(fullConf)
err = testutils.CmdDelWithArgs(args, func() error {
return cmdDel(args)
})
Expect(err).NotTo(HaveOccurred())
validateCleanedUp(fullConf)
return nil
})
Expect(err).NotTo(HaveOccurred())
})
})