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[Security Hardened Kubernetes Cluster] Add labelSelectors to rule options #589

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Merged
gardener-prow merged 4 commits into from
Sep 23, 2025
Merged

[Security Hardened Kubernetes Cluster] Add labelSelectors to rule options #589

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efa02f5
Add labelSelectors to all Hardened K8s rules
AleksandarSavchev Sep 12, 2025
db9a604
Adapt example files
AleksandarSavchev Sep 12, 2025
8aa5278
Fix copy/paste typo
AleksandarSavchev Sep 12, 2025
f1e0d8b
Return nil error on Errored check result
AleksandarSavchev Sep 16, 2025
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95 changes: 57 additions & 38 deletions example/config/managedk8s.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -183,19 +183,22 @@ providers: # contains information about known providers
# justification: "the whole rule is accepted for ... reasons"
# args:
# acceptedNamespaces:
# - matchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# acceptedTraffic:
# ingress: true
# egress: true
# - ruleID: "2001"
# args:
# acceptedPods:
# - matchLabels:
# foo: bar
# namespaceMatchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# namespaceLabelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# - ruleID: "2002"
# args:
Expand All @@ -207,28 +210,34 @@ providers: # contains information about known providers
# - ruleID: "2003"
# args:
# acceptedPods:
# - matchLabels:
# foo: bar
# namespaceMatchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# namespaceLabelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# volumeNames:
# - "volume-a"
# - "volume-b"
# - matchLabels:
# foo: baz
# namespaceMatchLabels:
# foo: baz
# - labelSelector:
# matchLabels:
# foo: baz
# namespaceLabelSelector:
# matchLabels:
# foo: baz
# justification: "justification"
# volumeNames:
# - "*" # a wildcard can be used to match against all volumes in an accepted pod
# - ruleID: "2004"
# args:
# acceptedServices:
# - matchLabels:
# foo: bar
# namespaceMatchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# namespaceLabelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# - ruleID: "2005"
# args:
Expand All @@ -237,42 +246,52 @@ providers: # contains information about known providers
# - ruleID: "2006"
# args:
# acceptedRoles:
# - matchLabels:
# foo: bar
# namespaceMatchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# namespaceLabelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# acceptedClusterRoles:
# - matchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# - ruleID: "2007"
# args:
# acceptedRoles:
# - matchLabels:
# foo: bar
# namespaceMatchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# namespaceLabelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# acceptedClusterRoles:
# - matchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# - ruleID: "2008"
# args:
# acceptedPods:
# - matchLabels:
# foo: bar
# namespaceMatchLabels:
# foo: bar
# - labelSelector:
# matchLabels:
# foo: bar
# namespaceLabelSelector:
# matchLabels:
# foo: bar
# justification: "justification"
# volumeNames:
# - "volume-a"
# - "volume-b"
# - matchLabels:
# foo: baz
# namespaceMatchLabels:
# foo: baz
# - labelSelector:
# matchLabels:
# foo: baz
# namespaceLabelSelector:
# matchLabels:
# foo: baz
# justification: "justification"
# volumeNames:
# - "*" # a wildcard can be used to match against all volumes in an accepted pod
Expand Down
83 changes: 50 additions & 33 deletions example/guides/security-hardened-k8s-shoot.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -14,75 +14,92 @@ providers:
- ruleID: "2000"
args:
acceptedNamespaces:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "Gardener managed namespaces are accepted to allow traffic by default."
acceptedTraffic:
ingress: true
egress: true
- ruleID: "2001"
args:
acceptedPods:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceMatchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceLabelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "Gardener managed resources are accepted to allow privilege escalation."
- ruleID: "2003"
args:
acceptedPods:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceMatchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceLabelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "Gardener managed resources are accepted to use a wider range of volume types."
volumeNames:
- "*"
- ruleID: "2004"
args:
acceptedServices:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceMatchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceLabelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "Gardener managed services are accepted to be of type NodePort."
- ruleID: "2006"
args:
acceptedRoles:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceMatchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceLabelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "Roles managed by Gardener are accepted to use wildcards in RBAC resources."
acceptedClusterRoles:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "ClusterRoles managed by Gardener are accepted to use wildcards in RBAC resources."
- matchLabels:
kubernetes.io/bootstrapping: rbac-defaults
- labelSelector:
matchLabels:
kubernetes.io/bootstrapping: rbac-defaults
justification: "Kubernetes default ClusterRoles are accepted to use wildcards in RBAC resources."
- ruleID: "2007"
args:
acceptedRoles:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceMatchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceLabelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "Roles managed by Gardener are accepted to use wildcards in RBAC verbs."
acceptedClusterRoles:
- matchLabels:
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "ClusterRoles managed by Gardener are accepted to use wildcards in RBAC verbs."
- matchLabels:
kubernetes.io/bootstrapping: rbac-defaults
- labelSelector:
matchLabels:
kubernetes.io/bootstrapping: rbac-defaults
justification: "Kubernetes default ClusterRoles are accepted to use wildcards in RBAC verbs."
- ruleID: "2008"
args:
acceptedPods:
- matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceMatchLabels:
resources.gardener.cloud/managed-by: gardener
- labelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
namespaceLabelSelector:
matchLabels:
resources.gardener.cloud/managed-by: gardener
justification: "Gardener managed resources are accepted to use a wider range of volume types."
volumeNames:
- "*"
Expand Down
39 changes: 22 additions & 17 deletions pkg/provider/managedk8s/ruleset/securityhardenedk8s/rules/2000.go
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Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,11 @@ import (
"context"
"slices"

corev1 "k8s.io/api/core/v1"
networkingv1 "k8s.io/api/networking/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"sigs.k8s.io/controller-runtime/pkg/client"

"github.com/gardener/diki/pkg/internal/utils"
kubeutils "github.com/gardener/diki/pkg/kubernetes/utils"
"github.com/gardener/diki/pkg/rule"
"github.com/gardener/diki/pkg/shared/kubernetes/option"
Expand Down Expand Up @@ -127,7 +125,10 @@ func (r *Rule2000) Run(ctx context.Context) (rule.RuleResult, error) {
if deniesAllIngress && !allowsAllIngress {
checkResults = append(checkResults, rule.PassedCheckResult("Ingress traffic is denied by default.", deniesAllIngressTarget))
} else {
accepted, justification := r.acceptedIngress(namespace)
accepted, justification, err := r.acceptedIngress(namespace.Labels)
if err != nil {
return rule.Result(r, rule.ErroredCheckResult(err.Error(), rule.NewTarget())), nil
}

acceptedTarget := target
msg := "Namespace is accepted to allow Ingress traffic by default."
Expand All @@ -152,7 +153,10 @@ func (r *Rule2000) Run(ctx context.Context) (rule.RuleResult, error) {
if deniesAllEgress && !allowsAllEgress {
checkResults = append(checkResults, rule.PassedCheckResult("Egress traffic is denied by default.", deniesAllEgressTarget))
} else {
accepted, justification := r.acceptedEgress(namespace)
accepted, justification, err := r.acceptedEgress(namespace.Labels)
if err != nil {
return rule.Result(r, rule.ErroredCheckResult(err.Error(), rule.NewTarget())), nil
}

acceptedTarget := target
msg := "Namespace is accepted to allow Egress traffic by default."
Expand All @@ -178,33 +182,34 @@ func (r *Rule2000) Run(ctx context.Context) (rule.RuleResult, error) {
return rule.Result(r, checkResults...), nil
}

func (r *Rule2000) acceptedIngress(namespace corev1.Namespace) (bool, string) {
func (r *Rule2000) acceptedIngress(namespaceLabels map[string]string) (bool, string, error) {
if r.Options == nil {
return false, ""
return false, "", nil
}

for _, acceptedNamespace := range r.Options.AcceptedNamespaces {

if utils.MatchLabels(namespace.Labels, acceptedNamespace.MatchLabels) &&
acceptedNamespace.AcceptedTraffic.Ingress {
return true, acceptedNamespace.Justification
if matches, err := acceptedNamespace.Matches(namespaceLabels); err != nil {
return false, "", err
} else if matches && acceptedNamespace.AcceptedTraffic.Ingress {
return true, acceptedNamespace.Justification, nil
}
}

return false, ""
return false, "", nil
}

func (r *Rule2000) acceptedEgress(namespace corev1.Namespace) (bool, string) {
func (r *Rule2000) acceptedEgress(namespaceLabels map[string]string) (bool, string, error) {
if r.Options == nil {
return false, ""
return false, "", nil
}

for _, acceptedNamespace := range r.Options.AcceptedNamespaces {
if utils.MatchLabels(namespace.Labels, acceptedNamespace.MatchLabels) &&
acceptedNamespace.AcceptedTraffic.Egress {
return true, acceptedNamespace.Justification
if matches, err := acceptedNamespace.Matches(namespaceLabels); err != nil {
return false, "", err
} else if matches && acceptedNamespace.AcceptedTraffic.Egress {
return true, acceptedNamespace.Justification, nil
}
}

return false, ""
return false, "", nil
}
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