forked from hswaw/hscloud
cluster/admitomatic: finish up ingress admission logic
This gives us nearly everything required to run the admission controller. In addition to checking for allowed domains, we also do some nginx-inress-controller security checks. Change-Id: Ib187de6d2c06c58bd8c320503d4f850df2ec8abdmaster
parent
649565324b
commit
5d2c8fcda0
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@ -12,6 +12,8 @@ go_library(
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"//go/mirko:go_default_library",
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"@com_github_golang_glog//:go_default_library",
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"@io_k8s_api//admission/v1beta1:go_default_library",
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"@io_k8s_api//networking/v1beta1:go_default_library",
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"@io_k8s_apimachinery//pkg/apis/meta/v1:go_default_library",
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],
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)
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@ -25,4 +27,10 @@ go_test(
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name = "go_default_test",
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srcs = ["ingress_test.go"],
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embed = [":go_default_library"],
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deps = [
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"@io_k8s_api//admission/v1beta1:go_default_library",
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"@io_k8s_api//networking/v1beta1:go_default_library",
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"@io_k8s_apimachinery//pkg/apis/meta/v1:go_default_library",
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"@io_k8s_apimachinery//pkg/runtime:go_default_library",
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],
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)
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@ -1,10 +1,15 @@
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package main
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import (
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"encoding/json"
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"fmt"
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"strings"
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"github.com/golang/glog"
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admission "k8s.io/api/admission/v1beta1"
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networking "k8s.io/api/networking/v1beta1"
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meta "k8s.io/apimachinery/pkg/apis/meta/v1"
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)
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// ingressFilter is a filter which allows or denies the creation of an ingress
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@ -125,6 +130,99 @@ func (i *ingressFilter) admit(req *admission.AdmissionRequest) (*admission.Admis
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if req.Kind.Group != "networking.k8s.io" || req.Kind.Kind != "Ingress" {
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return nil, fmt.Errorf("not an ingress")
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}
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// TODO(q3k); implement
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return nil, fmt.Errorf("unimplemented")
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result := func(s string, args ...interface{}) (*admission.AdmissionResponse, error) {
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res := &admission.AdmissionResponse{
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UID: req.UID,
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}
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if s == "" {
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res.Allowed = true
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} else {
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res.Allowed = false
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res.Result = &meta.Status{
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Code: 403,
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Message: fmt.Sprintf("admitomatic: %s", fmt.Sprintf(s, args...)),
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}
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}
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return res, nil
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}
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// Permit any actions on critical system namespaes. See:
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// https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/
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// “Avoiding operating on the kube-system namespace”
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if req.Namespace == "kube-system" {
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return result("")
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}
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switch req.Operation {
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case "CREATE":
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case "UPDATE":
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default:
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// We only care about creations/updates, everything else is referred to plain RBAC.
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return result("")
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}
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ingress := networking.Ingress{}
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err := json.Unmarshal(req.Object.Raw, &ingress)
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if err != nil {
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glog.Errorf("Unmarshaling Ingress failed: %v", err)
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return result("invalid object")
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}
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// Check TLS config for hosts.
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for j, t := range ingress.Spec.TLS {
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for k, h := range t.Hosts {
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if strings.Contains(h, "*") {
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// TODO(q3k): support wildcards
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return result("wildcard host %q (%d in TLS entry %d) is not permitted", h, k, j)
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}
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if !i.domainAllowed(req.Namespace, h) {
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return result("host %q (%d) in TLS entry %d is not allowed in namespace %q", h, k, j, req.Namespace)
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}
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}
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}
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// Check rules for hosts.
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for j, r := range ingress.Spec.Rules {
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h := r.Host
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// Per IngressRule spec:
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// If the host is unspecified, the Ingress routes all traffic based
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// on the specified IngressRuleValue. Host can be "precise" which is
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// a domain name without the terminating dot of a network host (e.g.
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// "foo.bar.com") or "wildcard", which is a domain name prefixed with
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// a single wildcard label (e.g. "*.foo.com").
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//
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// We reject everything other than precise hosts.
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if h == "" {
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return result("empty host %q (in rule %d) is not permitted", h, j)
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}
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if strings.Contains(h, "*") {
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// TODO(q3k): support wildcards
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return result("wildcard host %q (in rule %d) is not permitted", h, j)
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}
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if !i.domainAllowed(req.Namespace, h) {
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return result("host %q (in rule %d) is not allowed in namespace %q", h, j, req.Namespace)
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}
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}
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// Only allow a trusted subset of n-i-c annotations.
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// TODO(q3k): allow opt-out for some namespaces
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allowed := map[string]bool{
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"proxy-body-size": true,
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"ssl-redirect": true,
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"backend-protocol": true,
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}
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prefix := "nginx.ingress.kubernetes.io/"
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for k, _ := range ingress.Annotations {
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if !strings.HasPrefix(k, prefix) {
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continue
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}
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k = strings.TrimPrefix(k, prefix)
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if !allowed[k] {
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return result("forbidden annotation %q", k)
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}
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}
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// All clear, accept this Ingress.
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return result("")
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}
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@ -1,6 +1,15 @@
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package main
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import "testing"
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import (
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"encoding/json"
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"strings"
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"testing"
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admission "k8s.io/api/admission/v1beta1"
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networking "k8s.io/api/networking/v1beta1"
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meta "k8s.io/apimachinery/pkg/apis/meta/v1"
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runtime "k8s.io/apimachinery/pkg/runtime"
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)
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func TestPatterns(t *testing.T) {
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f := ingressFilter{}
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@ -76,3 +85,121 @@ func TestMatch(t *testing.T) {
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}
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}
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}
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func TestIngressPermitted(t *testing.T) {
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f := ingressFilter{}
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// Errors discarded, tested in TestPatterns.
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f.allow("matrix", "matrix.hackerspace.pl")
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f.allow("ceph-waw3", "*.hackerspace.pl")
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f.allow("personal-q3k", "*.k0.q3k.org")
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f.allow("personal-vuko", "shells.vuko.pl")
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f.allow("minecraft", "*.k0.q3k.org")
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mkReq := func(ns string, annotations map[string]string, is *networking.IngressSpec) *admission.AdmissionRequest {
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i := &networking.Ingress{
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Spec: *is,
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}
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i.Annotations = annotations
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raw, err := json.Marshal(i)
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if err != nil {
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t.Fatalf("marshaling test ingress: %v", err)
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}
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return &admission.AdmissionRequest{
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UID: "test",
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Kind: meta.GroupVersionKind{
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Group: "networking.k8s.io",
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Version: "v1beta1",
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Kind: "Ingress",
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},
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Namespace: ns,
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Operation: "CREATE",
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Object: runtime.RawExtension{
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Raw: raw,
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},
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}
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}
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for i, el := range []struct {
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req *admission.AdmissionRequest
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err string
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}{
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// 0: unrelated domain, should be allowed
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{mkReq("default", nil, &networking.IngressSpec{
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Rules: []networking.IngressRule{
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{Host: "example.com"},
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},
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TLS: []networking.IngressTLS{
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{
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Hosts: []string{"example.com"},
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},
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},
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}), ""},
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// 1: permitted restricted domain, should be allowed
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{mkReq("matrix", nil, &networking.IngressSpec{
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Rules: []networking.IngressRule{
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{Host: "matrix.hackerspace.pl"},
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},
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TLS: []networking.IngressTLS{
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{
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Hosts: []string{"matrix.hackerspace.pl"},
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},
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},
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}), ""},
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// 2: forbidden restricted domain, should be rejected
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{mkReq("personal-hacker", nil, &networking.IngressSpec{
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Rules: []networking.IngressRule{
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{Host: "matrix.hackerspace.pl"},
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},
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TLS: []networking.IngressTLS{
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{
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Hosts: []string{"matrix.hackerspace.pl"},
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},
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},
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}), "not allowed in namespace"},
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// 3: weird ingress but okay
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{mkReq("personal-hacker", nil, &networking.IngressSpec{}), ""},
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// 4: janky annotations, should be rejected
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{mkReq("matrix", map[string]string{
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"nginx.ingress.kubernetes.io/configuration-snippet": "omghax",
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}, &networking.IngressSpec{
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Rules: []networking.IngressRule{
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{Host: "matrix.hackerspace.pl"},
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},
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TLS: []networking.IngressTLS{
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{
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Hosts: []string{"matrix.hackerspace.pl"},
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},
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},
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}), "forbidden annotation"},
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// 5: accepted annotations, should be allowed
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{mkReq("matrix", map[string]string{
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"nginx.ingress.kubernetes.io/proxy-body-size": "2137",
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"foo.q3k.org/bar": "baz",
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}, &networking.IngressSpec{
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Rules: []networking.IngressRule{
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{Host: "matrix.hackerspace.pl"},
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},
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TLS: []networking.IngressTLS{
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{
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Hosts: []string{"matrix.hackerspace.pl"},
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},
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},
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}), ""},
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} {
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res, err := f.admit(el.req)
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if err != nil {
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t.Errorf("test %d: admit: %v", i, err)
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}
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if el.err == "" {
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if !res.Allowed {
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t.Errorf("test %d: wanted allow, got %q", i, res.Result.Message)
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}
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} else {
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if res.Allowed {
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t.Errorf("test %d: wanted %q, got allowed", i, el.err)
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} else if !strings.Contains(res.Result.Message, el.err) {
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t.Errorf("test %d: wanted %q, got %q", i, el.err, res.Result.Message)
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}
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}
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}
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}
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