use k8s psa admission package for getting pod spec

go.mod

@@ -23,6 +23,9 @@ require (
 	github.com/Azure/go-autorest/tracing v0.6.0 // indirect
 	github.com/PuerkitoBio/purell v1.1.1 // indirect
 	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/blang/semver/v4 v4.0.0 // indirect
+	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/emicklei/go-restful v2.9.5+incompatible // indirect
@@ -34,6 +37,7 @@ require (
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/google/gnostic v0.5.7-v3refs // indirect
+	github.com/google/go-cmp v0.5.5 // indirect
 	github.com/google/gofuzz v1.1.0 // indirect
 	github.com/imdario/mergo v0.3.5 // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
@@ -41,9 +45,14 @@ require (
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/mailru/easyjson v0.7.6 // indirect
 	github.com/mattn/go-runewidth v0.0.9 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/prometheus/client_golang v1.12.1 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.32.1 // indirect
+	github.com/prometheus/procfs v0.7.3 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	golang.org/x/crypto v0.0.0-20220214200702-86341886e292 // indirect
 	golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd // indirect

go.sum

@@ -77,15 +77,18 @@ github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiU
 github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kBD4zp0CCIs=
 github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJmJgSg28kpZDP6UIiPt0e0Oz0kqKNGyRaWEPv84=
+github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
 github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/certifi/gocertifi v0.0.0-20191021191039-0944d244cd40/go.mod h1:sGbDF6GwGcLpkNXPUTkMRoywsNa/ol15pxFe6ERfguA=
 github.com/certifi/gocertifi v0.0.0-20200922220541-2c3bb06c6054/go.mod h1:sGbDF6GwGcLpkNXPUTkMRoywsNa/ol15pxFe6ERfguA=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/cespare/xxhash/v2 v2.1.2 h1:YRXhKfTDauu4ajMg1TPgFO5jnlC2HCbmLXMcTG5cbYE=
 github.com/cespare/xxhash/v2 v2.1.2/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/chzyer/logex v1.1.10 h1:Swpa1K6QvQznwJRcfTfQJmTE72DqScAa40E+fbHEXEE=
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
@@ -242,6 +245,7 @@ github.com/google/pprof v0.0.0-20201203190320-1bf35d6f28c2/go.mod h1:kpwsk12EmLe
 github.com/google/pprof v0.0.0-20210122040257-d980be63207e/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20210226084205-cbba55b83ad5/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
+github.com/google/uuid v1.1.2 h1:EVhdT+1Kseyi1/pUmXKaFxYsDNy9RQYkMWRH68J/W7Y=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+vpHVxEJEs9eg=
 github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5mhpdKc/us6bOk=
@@ -322,6 +326,7 @@ github.com/mattn/go-isatty v0.0.3/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNx
 github.com/mattn/go-runewidth v0.0.9 h1:Lm995f3rfxdpd6TSmuVCHVb/QhupuXlYr8sCI/QdE+0=
 github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
+github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 h1:I0XW9+e1XWDxdcEniV4rQAIOPUGDq67JSCiRCgGCZLI=
 github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
 github.com/miekg/dns v1.0.14/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/mitchellh/cli v1.0.0/go.mod h1:hNIlj7HEI86fIcpObd7a0FcrxTWetlwJDGcceTlRvqc=
@@ -380,22 +385,26 @@ github.com/prometheus/client_golang v0.9.3/go.mod h1:/TN21ttK/J9q6uSwhBd54HahCDf
 github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5FsnadC4Ky3P0J6CfImo=
 github.com/prometheus/client_golang v1.7.1/go.mod h1:PY5Wy2awLA44sXw4AOSfFBetzPP4j5+D6mVACh+pe2M=
 github.com/prometheus/client_golang v1.11.0/go.mod h1:Z6t4BnS23TR94PD6BsDNk8yVqroYurpAkEiz0P2BEV0=
+github.com/prometheus/client_golang v1.12.1 h1:ZiaPsmm9uiBeaSMRznKsCDNtPCS0T3JVDGF+06gjBzk=
 github.com/prometheus/client_golang v1.12.1/go.mod h1:3Z9XVyYiZYEO+YQWt3RD2R3jrbd179Rt297l4aS6nDY=
 github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
 github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
+github.com/prometheus/client_model v0.2.0 h1:uq5h0d+GuxiXLJLNABMgp2qUWDPiLvgCzz2dUR+/W/M=
 github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/common v0.0.0-20181113130724-41aa239b4cce/go.mod h1:daVV7qP5qjZbuso7PdcryaAu0sAZbrN9i7WWcTMWvro=
 github.com/prometheus/common v0.4.0/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.10.0/go.mod h1:Tlit/dnDKsSWFlCLTWaA1cyBgKHSMdTB80sz/V91rCo=
 github.com/prometheus/common v0.26.0/go.mod h1:M7rCNAaPfAosfx8veZJCuw84e35h3Cfd9VFqTh1DIvc=
+github.com/prometheus/common v0.32.1 h1:hWIdL3N2HoUx3B8j3YN9mWor0qhY/NlEKZEaXxuIRh4=
 github.com/prometheus/common v0.32.1/go.mod h1:vu+V0TpY+O6vW9J44gczi3Ap/oXXR10b+M/gUGO4Hls=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/prometheus/procfs v0.0.0-20190507164030-5867b95ac084/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/procfs v0.0.2/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/procfs v0.1.3/go.mod h1:lV6e/gmhEcM9IjHGsFOCxxuZ+z1YqCvr4OA4YeYWdaU=
 github.com/prometheus/procfs v0.6.0/go.mod h1:cz+aTbrPOrUb4q7XlbU9ygM+/jj0fzG6c1xBZuNvfVA=
+github.com/prometheus/procfs v0.7.3 h1:4jVXhlkAyzOScmCkXBTOLRLTz8EeU+eyjrwB/EPq0VU=
 github.com/prometheus/procfs v0.7.3/go.mod h1:cz+aTbrPOrUb4q7XlbU9ygM+/jj0fzG6c1xBZuNvfVA=
 github.com/prometheus/tsdb v0.7.1/go.mod h1:qhTCs0VvXwvX/y3TZrWD7rabWM+ijKTux40TwIPHuXU=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=

pspmutating.go

@@ -18,16 +18,19 @@ package pspmigrator
 
 import (
 	"context"
+	"fmt"
 	"strings"
 
 	"github.com/go-test/deep"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/api/policy/v1beta1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/kubernetes"
+	psaadmission "k8s.io/pod-security-admission/admission"
 )
 
-func GetContainerSecurityContexts(podSpec v1.PodSpec) []*v1.SecurityContext {
+func GetContainerSecurityContexts(podSpec *v1.PodSpec) []*v1.SecurityContext {
 	// TODO reuse VisitContainers from k8s pkg/api/pod/util.go
 	scs := make([]*v1.SecurityContext, 0)
 	for _, c := range podSpec.Containers {
@@ -52,6 +55,29 @@ func GetPSPAnnotations(annotations map[string]string) map[string]string {
 	return pspAnnotations
 }
 
+func FetchControllerPod(kind, name, namespace string, clientset *kubernetes.Clientset) (*metav1.ObjectMeta, *v1.PodSpec, error) {
+	obj, err := FetchControllerObj(kind, name, namespace, clientset)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to fetch controller: %w", err)
+	}
+	return psaadmission.DefaultPodSpecExtractor{}.ExtractPodSpec(obj)
+}
+
+func FetchControllerObj(kind, name, namespace string, clientset *kubernetes.Clientset) (runtime.Object, error) {
+	// TODO review and document which controllers don't require special handling
+	// https://github.com/kubernetes/pod-security-admission/blob/master/admission/admission.go#L93
+	// for example, Deployments would fall under the ReplicaSet case so no need to have a case
+	// statement for Deployments.
+	switch kind {
+	case "ReplicaSet":
+		return clientset.AppsV1().ReplicaSets(namespace).Get(context.TODO(), name, metav1.GetOptions{})
+	case "DaemonSet":
+		return clientset.AppsV1().DaemonSets(namespace).Get(context.TODO(), name, metav1.GetOptions{})
+	default:
+		return nil, fmt.Errorf("unsupported controller kind %s", kind)
+	}
+}
+
 // IsPodBeingMutatedByPSP returns whether a pod is likely mutated by a PSP object. It also returns the difference
 // of the securityContext attribute between the parent controller (e.g. Deployment) and the running pod.
 func IsPodBeingMutatedByPSP(pod *v1.Pod, clientset *kubernetes.Clientset) (mutating bool, diff []string, err error) {
@@ -64,33 +90,22 @@ func IsPodBeingMutatedByPSP(pod *v1.Pod, clientset *kubernetes.Clientset) (mutat
 				break
 			}
 		}
-		var parentPod v1.PodTemplateSpec
-		if owner.Kind == "ReplicaSet" {
-			rs, err := clientset.AppsV1().ReplicaSets(pod.Namespace).Get(context.TODO(), owner.Name, metav1.GetOptions{})
-			if err != nil {
-				return false, diff, err
-			}
-			parentPod = rs.Spec.Template
-		}
-		if owner.Kind == "DaemonSet" {
-			ds, err := clientset.AppsV1().DaemonSets(pod.Namespace).Get(context.TODO(), owner.Name, metav1.GetOptions{})
-			if err != nil {
-				return false, diff, err
-			}
-			parentPod = ds.Spec.Template
-		}
 		if owner.Kind == "Node" {
 			// static pods launched by the node that can't be mutated
 			return false, diff, nil
 		}
+		parentPodMeta, parentPodSpec, err := FetchControllerPod(owner.Kind, owner.Name, pod.Namespace, clientset)
+		if err != nil {
+			return false, diff, err
+		}
 		// TODO investigate if 1st party library can be used such as github.com/google/go-cmp or smth from k8s
-		if diffNew := deep.Equal(GetContainerSecurityContexts(parentPod.Spec), GetContainerSecurityContexts(pod.Spec)); diffNew != nil {
+		if diffNew := deep.Equal(GetContainerSecurityContexts(parentPodSpec), GetContainerSecurityContexts(&pod.Spec)); diffNew != nil {
 			diff = append(diff, diffNew...)
 		}
-		if diffNew := deep.Equal(parentPod.Spec.SecurityContext, pod.Spec.SecurityContext); diffNew != nil {
+		if diffNew := deep.Equal(parentPodSpec.SecurityContext, pod.Spec.SecurityContext); diffNew != nil {
 			diff = append(diff, diffNew...)
 		}
-		if diffNew := deep.Equal(GetPSPAnnotations(parentPod.ObjectMeta.Annotations), GetPSPAnnotations(pod.ObjectMeta.Annotations)); diffNew != nil {
+		if diffNew := deep.Equal(GetPSPAnnotations(parentPodMeta.Annotations), GetPSPAnnotations(pod.ObjectMeta.Annotations)); diffNew != nil {
 			diff = append(diff, diffNew...)
 		}
 	}