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kyverno/pkg/validatingadmissionpolicy/validate.go
2024-12-12 07:13:09 +00:00

257 lines
8.8 KiB
Go

package validatingadmissionpolicy
import (
"context"
"fmt"
"strings"
"time"
"github.com/kyverno/kyverno/pkg/clients/dclient"
engineapi "github.com/kyverno/kyverno/pkg/engine/api"
celutils "github.com/kyverno/kyverno/pkg/utils/cel"
datautils "github.com/kyverno/kyverno/pkg/utils/data"
kubeutils "github.com/kyverno/kyverno/pkg/utils/kube"
"golang.org/x/text/cases"
"golang.org/x/text/language"
admissionregistrationv1 "k8s.io/api/admissionregistration/v1"
"k8s.io/api/admissionregistration/v1alpha1"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apiserver/pkg/admission"
"k8s.io/apiserver/pkg/admission/plugin/cel"
"k8s.io/apiserver/pkg/admission/plugin/validatingadmissionpolicy"
"k8s.io/apiserver/pkg/admission/plugin/validatingadmissionpolicy/matching"
"k8s.io/apiserver/pkg/admission/plugin/webhook/matchconditions"
celconfig "k8s.io/apiserver/pkg/apis/cel"
)
func GetKinds(policy v1alpha1.ValidatingAdmissionPolicy) []string {
var kindList []string
matchResources := policy.Spec.MatchConstraints
for _, rule := range matchResources.ResourceRules {
group := rule.APIGroups[0]
version := rule.APIVersions[0]
for _, resource := range rule.Resources {
isSubresource := kubeutils.IsSubresource(resource)
if isSubresource {
parts := strings.Split(resource, "/")
kind := cases.Title(language.English, cases.NoLower).String(parts[0])
kind, _ = strings.CutSuffix(kind, "s")
subresource := parts[1]
if group == "" {
kindList = append(kindList, strings.Join([]string{version, kind, subresource}, "/"))
} else {
kindList = append(kindList, strings.Join([]string{group, version, kind, subresource}, "/"))
}
} else {
resource = cases.Title(language.English, cases.NoLower).String(resource)
resource, _ = strings.CutSuffix(resource, "s")
kind := resource
if group == "" {
kindList = append(kindList, strings.Join([]string{version, kind}, "/"))
} else {
kindList = append(kindList, strings.Join([]string{group, version, kind}, "/"))
}
}
}
}
return kindList
}
func Validate(
policyData PolicyData,
resource unstructured.Unstructured,
namespaceSelectorMap map[string]map[string]string,
client dclient.Interface,
) (engineapi.EngineResponse, error) {
resPath := fmt.Sprintf("%s/%s/%s", resource.GetNamespace(), resource.GetKind(), resource.GetName())
policy := policyData.definition
bindings := policyData.bindings
engineResponse := engineapi.NewEngineResponse(resource, engineapi.NewValidatingAdmissionPolicy(policy), nil)
gvk := resource.GroupVersionKind()
gvr := schema.GroupVersionResource{
Group: gvk.Group,
Version: gvk.Version,
Resource: strings.ToLower(gvk.Kind) + "s",
}
var namespace *corev1.Namespace
namespaceName := resource.GetNamespace()
// Special case, the namespace object has the namespace of itself.
// unset it if the incoming object is a namespace
if gvk.Kind == "Namespace" && gvk.Version == "v1" && gvk.Group == "" {
namespaceName = ""
}
if namespaceName != "" {
namespace = &corev1.Namespace{
ObjectMeta: metav1.ObjectMeta{
Name: namespaceName,
Labels: namespaceSelectorMap[namespaceName],
},
}
}
a := admission.NewAttributesRecord(resource.DeepCopyObject(), nil, resource.GroupVersionKind(), resource.GetNamespace(), resource.GetName(), gvr, "", admission.Create, nil, false, nil)
if len(bindings) == 0 {
isMatch, err := matches(a, namespaceSelectorMap, *policy.Spec.MatchConstraints)
if err != nil {
return engineResponse, err
}
if !isMatch {
return engineResponse, nil
}
logger.V(3).Info("validate resource %s against policy %s", resPath, policy.GetName())
return validateResource(policy, nil, resource, *namespace, a)
}
if client != nil {
nsLister := NewCustomNamespaceLister(client)
matcher := validatingadmissionpolicy.NewMatcher(matching.NewMatcher(nsLister, client.GetKubeClient()))
// convert policy from v1alpha1 to v1beta1
v1beta1policy := ConvertValidatingAdmissionPolicy(policy)
// construct admission attributes
gvr, err := client.Discovery().GetGVRFromGVK(gvk)
if err != nil {
return engineResponse, err
}
a = admission.NewAttributesRecord(resource.DeepCopyObject(), nil, gvk, resource.GetNamespace(), resource.GetName(), gvr, "", admission.Create, nil, false, nil)
// check if policy matches the incoming resource
o := admission.NewObjectInterfacesFromScheme(runtime.NewScheme())
isMatch, _, _, err := matcher.DefinitionMatches(a, o, &v1beta1policy)
if err != nil {
return engineResponse, err
}
if !isMatch {
return engineResponse, nil
}
if namespaceName != "" {
namespace, err = client.GetKubeClient().CoreV1().Namespaces().Get(context.TODO(), namespaceName, metav1.GetOptions{})
if err != nil {
return engineResponse, err
}
}
for i, binding := range bindings {
// convert policy binding from v1alpha1 to v1beta1
v1beta1binding := ConvertValidatingAdmissionPolicyBinding(binding)
isMatch, err := matcher.BindingMatches(a, o, &v1beta1binding)
if err != nil {
return engineResponse, err
}
if !isMatch {
continue
}
logger.V(3).Info("validate resource %s against policy %s with binding %s", resPath, policy.GetName(), binding.GetName())
return validateResource(policy, &bindings[i], resource, *namespace, a)
}
} else {
for i, binding := range bindings {
isMatch, err := matches(a, namespaceSelectorMap, *binding.Spec.MatchResources)
if err != nil {
return engineResponse, err
}
if !isMatch {
continue
}
logger.V(3).Info("validate resource %s against policy %s with binding %s", resPath, policy.GetName(), binding.GetName())
return validateResource(policy, &bindings[i], resource, *namespace, a)
}
}
return engineResponse, nil
}
func validateResource(
policy v1alpha1.ValidatingAdmissionPolicy,
binding *v1alpha1.ValidatingAdmissionPolicyBinding,
resource unstructured.Unstructured,
namespace corev1.Namespace,
a admission.Attributes,
) (engineapi.EngineResponse, error) {
startTime := time.Now()
engineResponse := engineapi.NewEngineResponse(resource, engineapi.NewValidatingAdmissionPolicy(policy), nil)
policyResp := engineapi.NewPolicyResponse()
var ruleResp *engineapi.RuleResponse
// compile CEL expressions
matchConditions := ConvertMatchConditionsV1(policy.Spec.MatchConditions)
compiler, err := celutils.NewCompiler(policy.Spec.Validations, policy.Spec.AuditAnnotations, matchConditions, policy.Spec.Variables)
if err != nil {
return engineResponse, err
}
hasParam := policy.Spec.ParamKind != nil
optionalVars := cel.OptionalVariableDeclarations{HasParams: hasParam, HasAuthorizer: false}
compiler.CompileVariables(optionalVars)
var failPolicy admissionregistrationv1.FailurePolicyType
if policy.Spec.FailurePolicy == nil {
failPolicy = admissionregistrationv1.Fail
} else {
failPolicy = admissionregistrationv1.FailurePolicyType(*policy.Spec.FailurePolicy)
}
var matchPolicy v1alpha1.MatchPolicyType
if policy.Spec.MatchConstraints.MatchPolicy == nil {
matchPolicy = v1alpha1.Equivalent
} else {
matchPolicy = *policy.Spec.MatchConstraints.MatchPolicy
}
newMatcher := matchconditions.NewMatcher(compiler.CompileMatchExpressions(optionalVars), &failPolicy, "", string(matchPolicy), "")
validator := validatingadmissionpolicy.NewValidator(
compiler.CompileValidateExpressions(optionalVars),
newMatcher,
compiler.CompileAuditAnnotationsExpressions(optionalVars),
compiler.CompileMessageExpressions(optionalVars),
&failPolicy,
)
versionedAttr, _ := admission.NewVersionedAttributes(a, a.GetKind(), nil)
validateResult := validator.Validate(context.TODO(), a.GetResource(), versionedAttr, nil, &namespace, celconfig.RuntimeCELCostBudget, nil)
// no validations are returned if match conditions aren't met
if datautils.DeepEqual(validateResult, validatingadmissionpolicy.ValidateResult{}) {
ruleResp = engineapi.RuleSkip(policy.GetName(), engineapi.Validation, "match conditions aren't met")
} else {
isPass := true
for _, policyDecision := range validateResult.Decisions {
if policyDecision.Evaluation == validatingadmissionpolicy.EvalError {
isPass = false
ruleResp = engineapi.RuleError(policy.GetName(), engineapi.Validation, policyDecision.Message, nil)
break
} else if policyDecision.Action == validatingadmissionpolicy.ActionDeny {
isPass = false
ruleResp = engineapi.RuleFail(policy.GetName(), engineapi.Validation, policyDecision.Message)
break
}
}
if isPass {
ruleResp = engineapi.RulePass(policy.GetName(), engineapi.Validation, "")
}
}
if binding != nil {
ruleResp = ruleResp.WithBinding(binding)
}
policyResp.Add(engineapi.NewExecutionStats(startTime, time.Now()), *ruleResp)
engineResponse = engineResponse.WithPolicyResponse(policyResp)
return engineResponse, nil
}