Retool validation for pod HostNetwork ports

This will ensure that HostPort == ContainerPort for pods and that
HostPort == 0 || HostPort == ContainerPort for embedded PodSpecs.

pkg/apis/core/validation/validation.go

@@ -3481,15 +3481,35 @@ func validatePodDNSConfig(dnsConfig *core.PodDNSConfig, dnsPolicy *core.DNSPolic
 	return allErrs
 }
 
-func validateHostNetwork(hostNetwork bool, containers []core.Container, fldPath *field.Path) field.ErrorList {
+// validatePodHostNetworkDeps checks fields which depend on whether HostNetwork is
+// true or not.  It should be called on all PodSpecs, but opts can change what
+// is enforce.  E.g. opts.ResourceIsPod should only be set when called in the
+// context of a Pod, and not on PodSpecs which are embedded in other resources
+// (e.g. Deployments).
+func validatePodHostNetworkDeps(spec *core.PodSpec, fldPath *field.Path, opts PodValidationOptions) field.ErrorList {
+	// For <reasons> we keep `.HostNetwork` in .SecurityContext on the internal
+	// version of Pod.
+	hostNetwork := false
+	if spec.SecurityContext != nil {
+		hostNetwork = spec.SecurityContext.HostNetwork
+	}
+
 	allErrors := field.ErrorList{}
+
 	if hostNetwork {
-		for i, container := range containers {
+		fldPath := fldPath.Child("containers")
+		for i, container := range spec.Containers {
 			portsPath := fldPath.Index(i).Child("ports")
 			for i, port := range container.Ports {
 				idxPath := portsPath.Index(i)
-				if port.HostPort != port.ContainerPort {
-					allErrors = append(allErrors, field.Invalid(idxPath.Child("containerPort"), port.ContainerPort, "must match `hostPort` when `hostNetwork` is true"))
+				// At this point, we know that HostNetwork is true. If this
+				// PodSpec is in a Pod (opts.ResourceIsPod), then HostPort must
+				// be the same value as ContainerPort. If this PodSpec is in
+				// some other resource (e.g. Deployment) we allow 0 (i.e.
+				// unspecified) because it will be defaulted when the Pod is
+				// ultimately created, but we do not allow any other values.
+				if hp, cp := port.HostPort, port.ContainerPort; (opts.ResourceIsPod || hp != 0) && hp != cp {
+					allErrors = append(allErrors, field.Invalid(idxPath.Child("hostPort"), port.HostPort, "must match `containerPort` when `hostNetwork` is true"))
 				}
 			}
 		}
@@ -3694,6 +3714,9 @@ type PodValidationOptions struct {
 	AllowInvalidTopologySpreadConstraintLabelSelector bool
 	// Allow node selector additions for gated pods.
 	AllowMutableNodeSelectorAndNodeAffinity bool
+	// The top-level resource being validated is a Pod, not just a PodSpec
+	// embedded in some other resource.
+	ResourceIsPod bool
 }
 
 // validatePodMetadataAndSpec tests if required fields in the pod.metadata and pod.spec are set,
@@ -3709,8 +3732,6 @@ func validatePodMetadataAndSpec(pod *core.Pod, opts PodValidationOptions) field.
 	// we do additional validation only pertinent for pods and not pod templates
 	// this was done to preserve backwards compatibility
 
-	allErrs = append(allErrs, validatePodSecurityContext(pod.Spec.SecurityContext, &pod.Spec, specPath, specPath.Child("securityContext"), opts)...)
-
 	if pod.Spec.ServiceAccountName == "" {
 		for vi, volume := range pod.Spec.Volumes {
 			path := specPath.Child("volumes").Index(vi).Child("projected")
@@ -3793,6 +3814,7 @@ func ValidatePodSpec(spec *core.PodSpec, podMeta *metav1.ObjectMeta, fldPath *fi
 	allErrs = append(allErrs, validateContainers(spec.Containers, vols, podClaimNames, fldPath.Child("containers"), opts)...)
 	allErrs = append(allErrs, validateInitContainers(spec.InitContainers, spec.Containers, vols, podClaimNames, fldPath.Child("initContainers"), opts)...)
 	allErrs = append(allErrs, validateEphemeralContainers(spec.EphemeralContainers, spec.Containers, spec.InitContainers, vols, podClaimNames, fldPath.Child("ephemeralContainers"), opts)...)
+	allErrs = append(allErrs, validatePodHostNetworkDeps(spec, fldPath, opts)...)
 	allErrs = append(allErrs, validateRestartPolicy(&spec.RestartPolicy, fldPath.Child("restartPolicy"))...)
 	allErrs = append(allErrs, validateDNSPolicy(&spec.DNSPolicy, fldPath.Child("dnsPolicy"))...)
 	allErrs = append(allErrs, unversionedvalidation.ValidateLabels(spec.NodeSelector, fldPath.Child("nodeSelector"))...)
@@ -4399,18 +4421,6 @@ func validateSysctls(sysctls []core.Sysctl, fldPath *field.Path) field.ErrorList
 	return allErrs
 }
 
-// validatePodSecurityContext verifies the SecurityContext of a Pod, but only
-// when it is a Pod and not an embedded PodSpec.
-func validatePodSecurityContext(securityContext *core.PodSecurityContext, spec *core.PodSpec, specPath, scPath *field.Path, opts PodValidationOptions) field.ErrorList {
-	allErrs := field.ErrorList{}
-
-	if securityContext != nil {
-		allErrs = append(allErrs, validateHostNetwork(securityContext.HostNetwork, spec.Containers, specPath.Child("containers"))...)
-	}
-
-	return allErrs
-}
-
 // validatePodSpecSecurityContext verifies the SecurityContext of a PodSpec,
 // whether that is defined in a Pod or in an embedded PodSpec (e.g. a
 // Deployment's pod template).

pkg/apis/core/validation/validation_test.go

@@ -8816,7 +8816,10 @@ func TestValidatePodSpec(t *testing.T) {
 	}
 	for k, v := range successCases {
 		t.Run(k, func(t *testing.T) {
-			if errs := ValidatePodSpec(&v, nil, field.NewPath("field"), PodValidationOptions{}); len(errs) != 0 {
+			opts := PodValidationOptions{
+				ResourceIsPod: true,
+			}
+			if errs := ValidatePodSpec(&v, nil, field.NewPath("field"), opts); len(errs) != 0 {
 				t.Errorf("expected success: %v", errs)
 			}
 		})
@@ -8868,6 +8871,18 @@ func TestValidatePodSpec(t *testing.T) {
 			DNSPolicy:     core.DNSClusterFirst,
 			Containers:    []core.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
 		},
+		"with hostNetwork hostPort unspecified": {
+			Containers: []core.Container{
+				{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", Ports: []core.ContainerPort{
+					{HostPort: 0, ContainerPort: 2600, Protocol: "TCP"}},
+				},
+			},
+			SecurityContext: &core.PodSecurityContext{
+				HostNetwork: true,
+			},
+			RestartPolicy: core.RestartPolicyAlways,
+			DNSPolicy:     core.DNSClusterFirst,
+		},
 		"with hostNetwork hostPort not equal to containerPort": {
 			Containers: []core.Container{
 				{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", Ports: []core.ContainerPort{
@@ -9036,7 +9051,10 @@ func TestValidatePodSpec(t *testing.T) {
 		},
 	}
 	for k, v := range failureCases {
-		if errs := ValidatePodSpec(&v, nil, field.NewPath("field"), PodValidationOptions{}); len(errs) == 0 {
+		opts := PodValidationOptions{
+			ResourceIsPod: true,
+		}
+		if errs := ValidatePodSpec(&v, nil, field.NewPath("field"), opts); len(errs) == 0 {
 			t.Errorf("expected failure for %q", k)
 		}
 	}

pkg/registry/core/pod/strategy.go

@@ -112,6 +112,7 @@ func (podStrategy) PrepareForUpdate(ctx context.Context, obj, old runtime.Object
 func (podStrategy) Validate(ctx context.Context, obj runtime.Object) field.ErrorList {
 	pod := obj.(*api.Pod)
 	opts := podutil.GetValidationOptionsFromPodSpecAndMeta(&pod.Spec, nil, &pod.ObjectMeta, nil)
+	opts.ResourceIsPod = true
 	return corevalidation.ValidatePodCreate(pod, opts)
 }
 
@@ -141,6 +142,7 @@ func (podStrategy) ValidateUpdate(ctx context.Context, obj, old runtime.Object)
 	pod := obj.(*api.Pod)
 	oldPod := old.(*api.Pod)
 	opts := podutil.GetValidationOptionsFromPodSpecAndMeta(&pod.Spec, &oldPod.Spec, &pod.ObjectMeta, &oldPod.ObjectMeta)
+	opts.ResourceIsPod = true
 	return corevalidation.ValidatePodUpdate(obj.(*api.Pod), old.(*api.Pod), opts)
 }
 
@@ -225,6 +227,7 @@ func (podStatusStrategy) ValidateUpdate(ctx context.Context, obj, old runtime.Ob
 	pod := obj.(*api.Pod)
 	oldPod := old.(*api.Pod)
 	opts := podutil.GetValidationOptionsFromPodSpecAndMeta(&pod.Spec, &oldPod.Spec, &pod.ObjectMeta, &oldPod.ObjectMeta)
+	opts.ResourceIsPod = true
 
 	return corevalidation.ValidatePodStatusUpdate(obj.(*api.Pod), old.(*api.Pod), opts)
 }
@@ -264,6 +267,7 @@ func (podEphemeralContainersStrategy) ValidateUpdate(ctx context.Context, obj, o
 	newPod := obj.(*api.Pod)
 	oldPod := old.(*api.Pod)
 	opts := podutil.GetValidationOptionsFromPodSpecAndMeta(&newPod.Spec, &oldPod.Spec, &newPod.ObjectMeta, &oldPod.ObjectMeta)
+	opts.ResourceIsPod = true
 	return corevalidation.ValidatePodEphemeralContainersUpdate(newPod, oldPod, opts)
 }