mirror of
https://github.com/k3s-io/k3s.git
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386 lines
15 KiB
Go
386 lines
15 KiB
Go
// Apache License v2.0 (copyright Cloud Native Labs & Rancher Labs)
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// - modified from https://github.com/cloudnativelabs/kube-router/blob/ee9f6d890d10609284098229fa1e283ab5d83b93/pkg/controllers/netpol/pod.go
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// +build !windows
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package netpol
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import (
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"crypto/sha256"
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"encoding/base32"
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"fmt"
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"strings"
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"github.com/coreos/go-iptables/iptables"
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api "k8s.io/api/core/v1"
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"k8s.io/client-go/tools/cache"
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glog "k8s.io/klog"
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)
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func (npc *NetworkPolicyController) newPodEventHandler() cache.ResourceEventHandler {
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return cache.ResourceEventHandlerFuncs{
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AddFunc: func(obj interface{}) {
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npc.OnPodUpdate(obj)
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},
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UpdateFunc: func(oldObj, newObj interface{}) {
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newPoObj := newObj.(*api.Pod)
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oldPoObj := oldObj.(*api.Pod)
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if newPoObj.Status.Phase != oldPoObj.Status.Phase || newPoObj.Status.PodIP != oldPoObj.Status.PodIP {
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// for the network policies, we are only interested in pod status phase change or IP change
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npc.OnPodUpdate(newObj)
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}
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},
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DeleteFunc: func(obj interface{}) {
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npc.handlePodDelete(obj)
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},
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}
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}
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// OnPodUpdate handles updates to pods from the Kubernetes api server
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func (npc *NetworkPolicyController) OnPodUpdate(obj interface{}) {
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pod := obj.(*api.Pod)
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glog.V(2).Infof("Received update to pod: %s/%s", pod.Namespace, pod.Name)
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npc.RequestFullSync()
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}
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func (npc *NetworkPolicyController) handlePodDelete(obj interface{}) {
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pod, ok := obj.(*api.Pod)
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if !ok {
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tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
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if !ok {
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glog.Errorf("unexpected object type: %v", obj)
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return
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}
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if pod, ok = tombstone.Obj.(*api.Pod); !ok {
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glog.Errorf("unexpected object type: %v", obj)
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return
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}
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}
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glog.V(2).Infof("Received pod: %s/%s delete event", pod.Namespace, pod.Name)
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npc.RequestFullSync()
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}
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func (npc *NetworkPolicyController) syncPodFirewallChains(networkPoliciesInfo []networkPolicyInfo, version string) (map[string]bool, error) {
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activePodFwChains := make(map[string]bool)
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iptablesCmdHandler, err := iptables.New()
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if err != nil {
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glog.Fatalf("Failed to initialize iptables executor: %s", err.Error())
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}
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dropUnmarkedTrafficRules := func(podName, podNamespace, podFwChainName string) error {
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// add rule to log the packets that will be dropped due to network policy enforcement
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comment := "rule to log dropped traffic POD name:" + podName + " namespace: " + podNamespace
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args := []string{"-m", "comment", "--comment", comment, "-m", "mark", "!", "--mark", "0x10000/0x10000", "-j", "NFLOG", "--nflog-group", "100", "-m", "limit", "--limit", "10/minute", "--limit-burst", "10"}
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err = iptablesCmdHandler.AppendUnique("filter", podFwChainName, args...)
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if err != nil {
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return fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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// add rule to DROP if no applicable network policy permits the traffic
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comment = "rule to REJECT traffic destined for POD name:" + podName + " namespace: " + podNamespace
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args = []string{"-m", "comment", "--comment", comment, "-m", "mark", "!", "--mark", "0x10000/0x10000", "-j", "REJECT"}
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err = iptablesCmdHandler.AppendUnique("filter", podFwChainName, args...)
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if err != nil {
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return fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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// reset mark to let traffic pass through rest of the chains
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args = []string{"-j", "MARK", "--set-mark", "0/0x10000"}
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err = iptablesCmdHandler.AppendUnique("filter", podFwChainName, args...)
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if err != nil {
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return fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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return nil
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}
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// loop through the pods running on the node which to which ingress network policies to be applied
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ingressNetworkPolicyEnabledPods, err := npc.getIngressNetworkPolicyEnabledPods(networkPoliciesInfo, npc.nodeIP.String())
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if err != nil {
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return nil, err
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}
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for _, pod := range *ingressNetworkPolicyEnabledPods {
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// below condition occurs when we get trasient update while removing or adding pod
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// subsequent update will do the correct action
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if len(pod.ip) == 0 || pod.ip == "" {
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continue
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}
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// ensure pod specific firewall chain exist for all the pods that need ingress firewall
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podFwChainName := podFirewallChainName(pod.namespace, pod.name, version)
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err = iptablesCmdHandler.NewChain("filter", podFwChainName)
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if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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activePodFwChains[podFwChainName] = true
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// add entries in pod firewall to run through required network policies
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for _, policy := range networkPoliciesInfo {
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if _, ok := policy.targetPods[pod.ip]; ok {
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comment := "run through nw policy " + policy.name
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policyChainName := networkPolicyChainName(policy.namespace, policy.name, version)
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args := []string{"-m", "comment", "--comment", comment, "-j", policyChainName}
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exists, err := iptablesCmdHandler.Exists("filter", podFwChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
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if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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}
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}
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comment := "rule to permit the traffic traffic to pods when source is the pod's local node"
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args := []string{"-m", "comment", "--comment", comment, "-m", "addrtype", "--src-type", "LOCAL", "-d", pod.ip, "-j", "ACCEPT"}
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exists, err := iptablesCmdHandler.Exists("filter", podFwChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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// ensure statefull firewall, that permits return traffic for the traffic originated by the pod
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comment = "rule for stateful firewall for pod"
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args = []string{"-m", "comment", "--comment", comment, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}
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exists, err = iptablesCmdHandler.Exists("filter", podFwChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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// ensure there is rule in filter table and FORWARD chain to jump to pod specific firewall chain
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// this rule applies to the traffic getting routed (coming for other node pods)
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comment = "rule to jump traffic destined to POD name:" + pod.name + " namespace: " + pod.namespace +
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" to chain " + podFwChainName
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args = []string{"-m", "comment", "--comment", comment, "-d", pod.ip, "-j", podFwChainName}
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exists, err = iptablesCmdHandler.Exists("filter", kubeForwardChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.Insert("filter", kubeForwardChainName, 1, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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// ensure there is rule in filter table and OUTPUT chain to jump to pod specific firewall chain
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// this rule applies to the traffic from a pod getting routed back to another pod on same node by service proxy
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exists, err = iptablesCmdHandler.Exists("filter", kubeOutputChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.Insert("filter", kubeOutputChainName, 1, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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// ensure there is rule in filter table and forward chain to jump to pod specific firewall chain
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// this rule applies to the traffic getting switched (coming for same node pods)
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comment = "rule to jump traffic destined to POD name:" + pod.name + " namespace: " + pod.namespace +
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" to chain " + podFwChainName
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args = []string{"-m", "physdev", "--physdev-is-bridged",
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"-m", "comment", "--comment", comment,
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"-d", pod.ip,
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"-j", podFwChainName}
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exists, err = iptablesCmdHandler.Exists("filter", kubeForwardChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err = iptablesCmdHandler.Insert("filter", kubeForwardChainName, 1, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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err = dropUnmarkedTrafficRules(pod.name, pod.namespace, podFwChainName)
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if err != nil {
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return nil, err
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}
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}
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// loop through the pods running on the node which egress network policies to be applied
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egressNetworkPolicyEnabledPods, err := npc.getEgressNetworkPolicyEnabledPods(networkPoliciesInfo, npc.nodeIP.String())
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if err != nil {
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return nil, err
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}
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for _, pod := range *egressNetworkPolicyEnabledPods {
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// below condition occurs when we get trasient update while removing or adding pod
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// subsequent update will do the correct action
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if len(pod.ip) == 0 || pod.ip == "" {
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continue
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}
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// ensure pod specific firewall chain exist for all the pods that need egress firewall
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podFwChainName := podFirewallChainName(pod.namespace, pod.name, version)
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err = iptablesCmdHandler.NewChain("filter", podFwChainName)
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if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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activePodFwChains[podFwChainName] = true
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// add entries in pod firewall to run through required network policies
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for _, policy := range networkPoliciesInfo {
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if _, ok := policy.targetPods[pod.ip]; ok {
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comment := "run through nw policy " + policy.name
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policyChainName := networkPolicyChainName(policy.namespace, policy.name, version)
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args := []string{"-m", "comment", "--comment", comment, "-j", policyChainName}
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exists, err := iptablesCmdHandler.Exists("filter", podFwChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
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if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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}
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}
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// ensure statefull firewall, that permits return traffic for the traffic originated by the pod
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comment := "rule for stateful firewall for pod"
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args := []string{"-m", "comment", "--comment", comment, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}
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exists, err := iptablesCmdHandler.Exists("filter", podFwChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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egressFilterChains := []string{kubeInputChainName, kubeForwardChainName, kubeOutputChainName}
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for _, chain := range egressFilterChains {
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// ensure there is rule in filter table and FORWARD chain to jump to pod specific firewall chain
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// this rule applies to the traffic getting forwarded/routed (traffic from the pod destinted
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// to pod on a different node)
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comment = "rule to jump traffic from POD name:" + pod.name + " namespace: " + pod.namespace +
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" to chain " + podFwChainName
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args = []string{"-m", "comment", "--comment", comment, "-s", pod.ip, "-j", podFwChainName}
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exists, err = iptablesCmdHandler.Exists("filter", chain, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err := iptablesCmdHandler.AppendUnique("filter", chain, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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}
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// ensure there is rule in filter table and forward chain to jump to pod specific firewall chain
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// this rule applies to the traffic getting switched (coming for same node pods)
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comment = "rule to jump traffic from POD name:" + pod.name + " namespace: " + pod.namespace +
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" to chain " + podFwChainName
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args = []string{"-m", "physdev", "--physdev-is-bridged",
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"-m", "comment", "--comment", comment,
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"-s", pod.ip,
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"-j", podFwChainName}
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exists, err = iptablesCmdHandler.Exists("filter", kubeForwardChainName, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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if !exists {
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err = iptablesCmdHandler.Insert("filter", kubeForwardChainName, 1, args...)
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if err != nil {
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return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
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}
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}
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err = dropUnmarkedTrafficRules(pod.name, pod.namespace, podFwChainName)
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if err != nil {
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return nil, err
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}
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}
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return activePodFwChains, nil
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}
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func (npc *NetworkPolicyController) getIngressNetworkPolicyEnabledPods(networkPoliciesInfo []networkPolicyInfo, nodeIP string) (*map[string]podInfo, error) {
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nodePods := make(map[string]podInfo)
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for _, obj := range npc.podLister.List() {
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pod := obj.(*api.Pod)
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if strings.Compare(pod.Status.HostIP, nodeIP) != 0 {
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continue
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}
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for _, policy := range networkPoliciesInfo {
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if policy.namespace != pod.ObjectMeta.Namespace {
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continue
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}
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_, ok := policy.targetPods[pod.Status.PodIP]
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if ok && (policy.policyType == "both" || policy.policyType == "ingress") {
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glog.V(2).Infof("Found pod name: " + pod.ObjectMeta.Name + " namespace: " + pod.ObjectMeta.Namespace + " for which network policies need to be applied.")
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nodePods[pod.Status.PodIP] = podInfo{ip: pod.Status.PodIP,
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name: pod.ObjectMeta.Name,
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namespace: pod.ObjectMeta.Namespace,
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labels: pod.ObjectMeta.Labels}
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break
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}
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}
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}
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return &nodePods, nil
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}
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func (npc *NetworkPolicyController) getEgressNetworkPolicyEnabledPods(networkPoliciesInfo []networkPolicyInfo, nodeIP string) (*map[string]podInfo, error) {
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nodePods := make(map[string]podInfo)
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for _, obj := range npc.podLister.List() {
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pod := obj.(*api.Pod)
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if strings.Compare(pod.Status.HostIP, nodeIP) != 0 {
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continue
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}
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for _, policy := range networkPoliciesInfo {
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if policy.namespace != pod.ObjectMeta.Namespace {
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continue
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}
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_, ok := policy.targetPods[pod.Status.PodIP]
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if ok && (policy.policyType == "both" || policy.policyType == "egress") {
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glog.V(2).Infof("Found pod name: " + pod.ObjectMeta.Name + " namespace: " + pod.ObjectMeta.Namespace + " for which network policies need to be applied.")
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nodePods[pod.Status.PodIP] = podInfo{ip: pod.Status.PodIP,
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name: pod.ObjectMeta.Name,
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namespace: pod.ObjectMeta.Namespace,
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labels: pod.ObjectMeta.Labels}
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break
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}
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}
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}
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return &nodePods, nil
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}
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func podFirewallChainName(namespace, podName string, version string) string {
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hash := sha256.Sum256([]byte(namespace + podName + version))
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encoded := base32.StdEncoding.EncodeToString(hash[:])
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return kubePodFirewallChainPrefix + encoded[:16]
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}
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