Merge pull request #116054 from jpbetz/secondary-authz

KEP-3488: Implement secondary authz for ValidatingAdmissionPolicy

Kubernetes-commit: 64259b43b8e5b7c086bf2b74743dc7e73ebe37e3
This commit is contained in:
Kubernetes Publisher 2023-03-06 11:54:16 -08:00
commit 044de75c61
19 changed files with 1127 additions and 85 deletions

8
go.mod
View File

@ -42,9 +42,9 @@ require (
google.golang.org/protobuf v1.28.1
gopkg.in/natefinch/lumberjack.v2 v2.0.0
gopkg.in/square/go-jose.v2 v2.6.0
k8s.io/api v0.0.0-20230304080250-2d949b7889c7
k8s.io/api v0.0.0-20230306232903-507c3640d5c3
k8s.io/apimachinery v0.0.0-20230303235435-f357b1fa74b7
k8s.io/client-go v0.0.0-20230304000204-06ad6b391d35
k8s.io/client-go v0.0.0-20230306193833-48ca73428a5d
k8s.io/component-base v0.0.0-20230304000900-3bf8af940f29
k8s.io/klog/v2 v2.90.1
k8s.io/kms v0.0.0-20230304001132-5439f76ca4a7
@ -124,9 +124,9 @@ require (
)
replace (
k8s.io/api => k8s.io/api v0.0.0-20230304080250-2d949b7889c7
k8s.io/api => k8s.io/api v0.0.0-20230306232903-507c3640d5c3
k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20230303235435-f357b1fa74b7
k8s.io/client-go => k8s.io/client-go v0.0.0-20230304000204-06ad6b391d35
k8s.io/client-go => k8s.io/client-go v0.0.0-20230306193833-48ca73428a5d
k8s.io/component-base => k8s.io/component-base v0.0.0-20230304000900-3bf8af940f29
k8s.io/kms => k8s.io/kms v0.0.0-20230304001132-5439f76ca4a7
)

8
go.sum
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@ -874,12 +874,12 @@ honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWh
honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
honnef.co/go/tools v0.0.1-2020.1.3/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
honnef.co/go/tools v0.0.1-2020.1.4/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
k8s.io/api v0.0.0-20230304080250-2d949b7889c7 h1:aiAGgZyin08AS6FReGcsRu4Jx++Z2h1jgqG4wl6mho8=
k8s.io/api v0.0.0-20230304080250-2d949b7889c7/go.mod h1:esKbT+6XB9TZUHyxlJVQ3zUM0abhQZ81Ic68eirO+xM=
k8s.io/api v0.0.0-20230306232903-507c3640d5c3 h1:mIsULdBj0NtBvxyl7GiNPpt8yrpZhIEdWrx7XykA0vU=
k8s.io/api v0.0.0-20230306232903-507c3640d5c3/go.mod h1:esKbT+6XB9TZUHyxlJVQ3zUM0abhQZ81Ic68eirO+xM=
k8s.io/apimachinery v0.0.0-20230303235435-f357b1fa74b7 h1:YN43Lvs3Pj9iQmuWGojeBiFdz1mkrxe0EZn7Ba3TMpQ=
k8s.io/apimachinery v0.0.0-20230303235435-f357b1fa74b7/go.mod h1:jlJwObMa4oKAEOMnAeEaqeiM+Fwd/CbAwNyQ7OaEwS0=
k8s.io/client-go v0.0.0-20230304000204-06ad6b391d35 h1:9uwNzISbibeQwpbp/a9OFj2Zk98INi4pJfByXGK5nGQ=
k8s.io/client-go v0.0.0-20230304000204-06ad6b391d35/go.mod h1:D9bGnWQ1292GhAR0f2uumanvVdOHddJlD+7OlyUorYM=
k8s.io/client-go v0.0.0-20230306193833-48ca73428a5d h1:rSK2FCQrMNWOBZnZwuF5fjUVEhv6EYcno7svdgcOxhQ=
k8s.io/client-go v0.0.0-20230306193833-48ca73428a5d/go.mod h1:bwEvXWHDzK2W1oimBN7Pr2YPWzAnkT9N/xiOOp7Znl8=
k8s.io/component-base v0.0.0-20230304000900-3bf8af940f29 h1:26PuXs5/GsCX5EPltZN9KjZqkW/EwYHaebfNmIK3Wxc=
k8s.io/component-base v0.0.0-20230304000900-3bf8af940f29/go.mod h1:1aFiUfjXiy45a88xJmd/nSkReVCoyShEHbGmWJQbp2Q=
k8s.io/klog/v2 v2.90.1 h1:m4bYOKall2MmOiRaR1J+We67Do7vm9KiQVlT96lnHUw=

View File

@ -17,6 +17,7 @@ limitations under the License.
package cel
import (
"fmt"
"sync"
"github.com/google/cel-go/cel"
@ -26,43 +27,35 @@ import (
)
const (
ObjectVarName = "object"
OldObjectVarName = "oldObject"
ParamsVarName = "params"
RequestVarName = "request"
ObjectVarName = "object"
OldObjectVarName = "oldObject"
ParamsVarName = "params"
RequestVarName = "request"
AuthorizerVarName = "authorizer"
RequestResourceAuthorizerVarName = "authorizer.requestResource"
checkFrequency = 100
)
type envs struct {
noParams *cel.Env
withParams *cel.Env
}
var (
initEnvsOnce sync.Once
initEnvs *envs
initEnvs envs
initEnvsErr error
)
func getEnvs() (*envs, error) {
func getEnvs() (envs, error) {
initEnvsOnce.Do(func() {
base, err := buildBaseEnv()
requiredVarsEnv, err := buildRequiredVarsEnv()
if err != nil {
initEnvsErr = err
return
}
noParams, err := buildNoParamsEnv(base)
initEnvs, err = buildWithOptionalVarsEnvs(requiredVarsEnv)
if err != nil {
initEnvsErr = err
return
}
withParams, err := buildWithParamsEnv(noParams)
if err != nil {
initEnvsErr = err
return
}
initEnvs = &envs{noParams: noParams, withParams: withParams}
})
return initEnvs, initEnvsErr
}
@ -81,7 +74,11 @@ func buildBaseEnv() (*cel.Env, error) {
return cel.NewEnv(opts...)
}
func buildNoParamsEnv(baseEnv *cel.Env) (*cel.Env, error) {
func buildRequiredVarsEnv() (*cel.Env, error) {
baseEnv, err := buildBaseEnv()
if err != nil {
return nil, err
}
var propDecls []cel.EnvOption
reg := apiservercel.NewRegistry(baseEnv)
@ -109,8 +106,33 @@ func buildNoParamsEnv(baseEnv *cel.Env) (*cel.Env, error) {
return env, nil
}
func buildWithParamsEnv(noParams *cel.Env) (*cel.Env, error) {
return noParams.Extend(cel.Variable(ParamsVarName, cel.DynType))
type envs map[OptionalVariableDeclarations]*cel.Env
func buildEnvWithVars(baseVarsEnv *cel.Env, options OptionalVariableDeclarations) (*cel.Env, error) {
var opts []cel.EnvOption
if options.HasParams {
opts = append(opts, cel.Variable(ParamsVarName, cel.DynType))
}
if options.HasAuthorizer {
opts = append(opts, cel.Variable(AuthorizerVarName, library.AuthorizerType))
opts = append(opts, cel.Variable(RequestResourceAuthorizerVarName, library.ResourceCheckType))
}
return baseVarsEnv.Extend(opts...)
}
func buildWithOptionalVarsEnvs(requiredVarsEnv *cel.Env) (envs, error) {
envs := make(envs, 4) // since the number of variable combinations is small, pre-build a environment for each
for _, hasParams := range []bool{false, true} {
for _, hasAuthorizer := range []bool{false, true} {
opts := OptionalVariableDeclarations{HasParams: hasParams, HasAuthorizer: hasAuthorizer}
env, err := buildEnvWithVars(requiredVarsEnv, opts)
if err != nil {
return nil, err
}
envs[opts] = env
}
}
return envs, nil
}
// buildRequestType generates a DeclType for AdmissionRequest. This may be replaced with a utility that
@ -168,7 +190,7 @@ type CompilationResult struct {
}
// CompileCELExpression returns a compiled CEL expression.
func CompileCELExpression(expressionAccessor ExpressionAccessor, hasParams bool) CompilationResult {
func CompileCELExpression(expressionAccessor ExpressionAccessor, optionalVars OptionalVariableDeclarations) CompilationResult {
var env *cel.Env
envs, err := getEnvs()
if err != nil {
@ -180,10 +202,15 @@ func CompileCELExpression(expressionAccessor ExpressionAccessor, hasParams bool)
ExpressionAccessor: expressionAccessor,
}
}
if hasParams {
env = envs.withParams
} else {
env = envs.noParams
env, ok := envs[optionalVars]
if !ok {
return CompilationResult{
Error: &apiservercel.Error{
Type: apiservercel.ErrorTypeInvalid,
Detail: fmt.Sprintf("compiler initialization failed: failed to load environment for %v", optionalVars),
},
ExpressionAccessor: expressionAccessor,
}
}
ast, issues := env.Compile(expressionAccessor.GetExpression())

View File

@ -26,6 +26,7 @@ func TestCompileValidatingPolicyExpression(t *testing.T) {
name string
expressions []string
hasParams bool
hasAuthorizer bool
errorExpressions map[string]string
}{
{
@ -99,6 +100,19 @@ func TestCompileValidatingPolicyExpression(t *testing.T) {
"request.userInfo.foo5 == 'nope'": "undefined field 'foo5'",
},
},
{
name: "with authorizer",
hasAuthorizer: true,
expressions: []string{
"authorizer.group('') != null",
},
},
{
name: "without authorizer",
errorExpressions: map[string]string{
"authorizer.group('') != null": "undeclared reference to 'authorizer'",
},
},
}
for _, tc := range cases {
@ -106,7 +120,7 @@ func TestCompileValidatingPolicyExpression(t *testing.T) {
for _, expr := range tc.expressions {
result := CompileCELExpression(&fakeExpressionAccessor{
expr,
}, tc.hasParams)
}, OptionalVariableDeclarations{HasParams: tc.hasParams, HasAuthorizer: true})
if result.Error != nil {
t.Errorf("Unexpected error: %v", result.Error)
}
@ -114,7 +128,7 @@ func TestCompileValidatingPolicyExpression(t *testing.T) {
for expr, expectErr := range tc.errorExpressions {
result := CompileCELExpression(&fakeExpressionAccessor{
expr,
}, tc.hasParams)
}, OptionalVariableDeclarations{HasParams: tc.hasParams, HasAuthorizer: tc.hasAuthorizer})
if result.Error == nil {
t.Errorf("Expected expression '%s' to contain '%v' but got no error", expr, expectErr)
continue

View File

@ -31,6 +31,7 @@ import (
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apiserver/pkg/admission"
"k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
"k8s.io/apiserver/pkg/cel/library"
)
// filterCompiler implement the interface FilterCompiler.
@ -42,7 +43,7 @@ func NewFilterCompiler() FilterCompiler {
}
type evaluationActivation struct {
object, oldObject, params, request interface{}
object, oldObject, params, request, authorizer, requestResourceAuthorizer interface{}
}
// ResolveName returns a value from the activation by qualified name, or false if the name
@ -54,9 +55,13 @@ func (a *evaluationActivation) ResolveName(name string) (interface{}, bool) {
case OldObjectVarName:
return a.oldObject, true
case ParamsVarName:
return a.params, true
return a.params, true // params may be null
case RequestVarName:
return a.request, true
case AuthorizerVarName:
return a.authorizer, a.authorizer != nil
case RequestResourceAuthorizerVarName:
return a.requestResourceAuthorizer, a.requestResourceAuthorizer != nil
default:
return nil, false
}
@ -69,13 +74,13 @@ func (a *evaluationActivation) Parent() interpreter.Activation {
}
// Compile compiles the cel expressions defined in the ExpressionAccessors into a Filter
func (c *filterCompiler) Compile(expressionAccessors []ExpressionAccessor, hasParam bool) Filter {
func (c *filterCompiler) Compile(expressionAccessors []ExpressionAccessor, options OptionalVariableDeclarations) Filter {
if len(expressionAccessors) == 0 {
return nil
}
compilationResults := make([]CompilationResult, len(expressionAccessors))
for i, expressionAccessor := range expressionAccessors {
compilationResults[i] = CompileCELExpression(expressionAccessor, hasParam)
compilationResults[i] = CompileCELExpression(expressionAccessor, options)
}
return NewFilter(compilationResults)
}
@ -113,9 +118,9 @@ func objectToResolveVal(r runtime.Object) (interface{}, error) {
return v.Object, nil
}
// Evaluate evaluates the compiled CEL expressions converting them into CELEvaluations
// ForInput evaluates the compiled CEL expressions converting them into CELEvaluations
// errors per evaluation are returned on the Evaluation object
func (f *filter) ForInput(versionedAttr *generic.VersionedAttributes, versionedParams runtime.Object, request *admissionv1.AdmissionRequest) ([]EvaluationResult, error) {
func (f *filter) ForInput(versionedAttr *generic.VersionedAttributes, request *admissionv1.AdmissionRequest, inputs OptionalVariableBindings) ([]EvaluationResult, error) {
// TODO: replace unstructured with ref.Val for CEL variables when native type support is available
evaluations := make([]EvaluationResult, len(f.compilationResults))
var err error
@ -128,9 +133,17 @@ func (f *filter) ForInput(versionedAttr *generic.VersionedAttributes, versionedP
if err != nil {
return nil, err
}
paramsVal, err := objectToResolveVal(versionedParams)
if err != nil {
return nil, err
var paramsVal, authorizerVal, requestResourceAuthorizerVal any
if inputs.VersionedParams != nil {
paramsVal, err = objectToResolveVal(inputs.VersionedParams)
if err != nil {
return nil, err
}
}
if inputs.Authorizer != nil {
authorizerVal = library.NewAuthorizerVal(versionedAttr.GetUserInfo(), inputs.Authorizer)
requestResourceAuthorizerVal = library.NewResourceAuthorizerVal(versionedAttr.GetUserInfo(), inputs.Authorizer, versionedAttr)
}
requestVal, err := convertObjectToUnstructured(request)
@ -138,10 +151,12 @@ func (f *filter) ForInput(versionedAttr *generic.VersionedAttributes, versionedP
return nil, err
}
va := &evaluationActivation{
object: objectVal,
oldObject: oldObjectVal,
params: paramsVal,
request: requestVal.Object,
object: objectVal,
oldObject: oldObjectVal,
params: paramsVal,
request: requestVal.Object,
authorizer: authorizerVal,
requestResourceAuthorizer: requestResourceAuthorizerVal,
}
for i, compilationResult := range f.compilationResults {

View File

@ -17,12 +17,18 @@ limitations under the License.
package cel
import (
"context"
"errors"
"fmt"
"reflect"
"strings"
"testing"
celtypes "github.com/google/cel-go/common/types"
"github.com/stretchr/testify/require"
"k8s.io/apiserver/pkg/authentication/user"
"k8s.io/apiserver/pkg/authorization/authorizer"
apiservercel "k8s.io/apiserver/pkg/cel"
corev1 "k8s.io/api/core/v1"
@ -81,7 +87,7 @@ func TestCompile(t *testing.T) {
for _, tc := range cases {
t.Run(tc.name, func(t *testing.T) {
var c filterCompiler
e := c.Compile(tc.validation, false)
e := c.Compile(tc.validation, OptionalVariableDeclarations{HasParams: false, HasAuthorizer: false})
if e == nil {
t.Fatalf("unexpected nil validator")
}
@ -144,6 +150,7 @@ func TestFilter(t *testing.T) {
validations []ExpressionAccessor
results []EvaluationResult
hasParamKind bool
authorizer authorizer.Authorizer
}{
{
name: "valid syntax for object",
@ -417,12 +424,204 @@ func TestFilter(t *testing.T) {
hasParamKind: true,
params: runtime.Object(nilUnstructured),
},
{
name: "test authorizer allow resource check",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.group('').resource('endpoints').check('create').allowed()",
},
},
attributes: newValidAttribute(&podObject, false),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: newAuthzAllowMatch(authorizer.AttributesRecord{
ResourceRequest: true,
Resource: "endpoints",
Verb: "create",
APIVersion: "*",
}),
},
{
name: "test authorizer allow resource check with all fields",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.group('apps').resource('deployments').subresource('status').namespace('test').name('backend').check('create').allowed()",
},
},
attributes: newValidAttribute(&podObject, false),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: newAuthzAllowMatch(authorizer.AttributesRecord{
ResourceRequest: true,
APIGroup: "apps",
Resource: "deployments",
Subresource: "status",
Namespace: "test",
Name: "backend",
Verb: "create",
APIVersion: "*",
}),
},
{
name: "test authorizer not allowed resource check one incorrect field",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.group('apps').resource('deployments').subresource('status').namespace('test').name('backend').check('create').allowed()",
},
},
attributes: newValidAttribute(&podObject, false),
results: []EvaluationResult{
{
EvalResult: celtypes.False,
},
},
authorizer: newAuthzAllowMatch(authorizer.AttributesRecord{
ResourceRequest: true,
APIGroup: "apps",
Resource: "deployments-xxxx",
Subresource: "status",
Namespace: "test",
Name: "backend",
Verb: "create",
APIVersion: "*",
}),
},
{
name: "test authorizer reason",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.group('').resource('endpoints').check('create').reason() == 'fake reason'",
},
},
attributes: newValidAttribute(&podObject, false),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: denyAll,
},
{
name: "test authorizer allow path check",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.path('/healthz').check('get').allowed()",
},
},
attributes: newValidAttribute(&podObject, false),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: newAuthzAllowMatch(authorizer.AttributesRecord{
Path: "/healthz",
Verb: "get",
}),
},
{
name: "test authorizer decision is denied path check",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.path('/healthz').check('get').allowed() == false",
},
},
attributes: newValidAttribute(&podObject, false),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: denyAll,
},
{
name: "test request resource authorizer allow check",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.requestResource.check('custom-verb').allowed()",
},
},
attributes: endpointCreateAttributes(),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: newAuthzAllowMatch(authorizer.AttributesRecord{
ResourceRequest: true,
APIGroup: "",
Resource: "endpoints",
Subresource: "",
Namespace: "default",
Name: "endpoints1",
Verb: "custom-verb",
APIVersion: "*",
}),
},
{
name: "test subresource request resource authorizer allow check",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.requestResource.check('custom-verb').allowed()",
},
},
attributes: endpointStatusUpdateAttributes(),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: newAuthzAllowMatch(authorizer.AttributesRecord{
ResourceRequest: true,
APIGroup: "",
Resource: "endpoints",
Subresource: "status",
Namespace: "default",
Name: "endpoints1",
Verb: "custom-verb",
APIVersion: "*",
}),
},
{
name: "test serviceAccount authorizer allow check",
validations: []ExpressionAccessor{
&condition{
Expression: "authorizer.serviceAccount('default', 'test-serviceaccount').group('').resource('endpoints').namespace('default').name('endpoints1').check('custom-verb').allowed()",
},
},
attributes: endpointCreateAttributes(),
results: []EvaluationResult{
{
EvalResult: celtypes.True,
},
},
authorizer: newAuthzAllowMatch(authorizer.AttributesRecord{
User: &user.DefaultInfo{
Name: "system:serviceaccount:default:test-serviceaccount",
Groups: []string{"system:serviceaccounts", "system:serviceaccounts:default"},
},
ResourceRequest: true,
APIGroup: "",
Resource: "endpoints",
Namespace: "default",
Name: "endpoints1",
Verb: "custom-verb",
APIVersion: "*",
}),
},
}
for _, tc := range cases {
t.Run(tc.name, func(t *testing.T) {
c := filterCompiler{}
f := c.Compile(tc.validations, tc.hasParamKind)
f := c.Compile(tc.validations, OptionalVariableDeclarations{HasParams: tc.hasParamKind, HasAuthorizer: tc.authorizer != nil})
if f == nil {
t.Fatalf("unexpected nil validator")
}
@ -435,7 +634,8 @@ func TestFilter(t *testing.T) {
t.Fatalf("unexpected error on conversion: %v", err)
}
evalResults, err := f.ForInput(versionedAttr, tc.params, CreateAdmissionRequest(versionedAttr.Attributes))
optionalVars := OptionalVariableBindings{VersionedParams: tc.params, Authorizer: tc.authorizer}
evalResults, err := f.ForInput(versionedAttr, CreateAdmissionRequest(versionedAttr.Attributes), optionalVars)
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
@ -582,3 +782,74 @@ func TestCompilationErrors(t *testing.T) {
})
}
}
var denyAll = fakeAuthorizer{defaultResult: authorizerResult{decision: authorizer.DecisionDeny, reason: "fake reason", err: nil}}
func newAuthzAllowMatch(match authorizer.AttributesRecord) fakeAuthorizer {
return fakeAuthorizer{
match: &authorizerMatch{
match: match,
authorizerResult: authorizerResult{decision: authorizer.DecisionAllow, reason: "", err: nil},
},
defaultResult: authorizerResult{decision: authorizer.DecisionDeny, reason: "", err: nil},
}
}
type fakeAuthorizer struct {
match *authorizerMatch
defaultResult authorizerResult
}
type authorizerResult struct {
decision authorizer.Decision
reason string
err error
}
type authorizerMatch struct {
authorizerResult
match authorizer.AttributesRecord
}
func (f fakeAuthorizer) Authorize(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
if f.match != nil {
other, ok := a.(*authorizer.AttributesRecord)
if !ok {
panic(fmt.Sprintf("unsupported type: %T", a))
}
if reflect.DeepEqual(f.match.match, *other) {
return f.match.decision, f.match.reason, f.match.err
}
}
return f.defaultResult.decision, f.defaultResult.reason, f.defaultResult.err
}
func endpointCreateAttributes() admission.Attributes {
name := "endpoints1"
namespace := "default"
var object, oldObject runtime.Object
object = &corev1.Endpoints{
TypeMeta: metav1.TypeMeta{
Kind: "Endpoints",
APIVersion: "v1",
},
ObjectMeta: metav1.ObjectMeta{
Name: name,
},
Subsets: []corev1.EndpointSubset{
{
Addresses: []corev1.EndpointAddress{{IP: "127.0.0.0"}},
},
},
}
gvk := schema.GroupVersionKind{Group: "", Version: "v1", Kind: "Endpoints"}
gvr := schema.GroupVersionResource{Group: "", Version: "v1", Resource: "endpoints"}
return admission.NewAttributesRecord(object, oldObject, gvk, namespace, name, gvr, "", admission.Create, &metav1.CreateOptions{}, false, nil)
}
func endpointStatusUpdateAttributes() admission.Attributes {
attrs := endpointCreateAttributes()
return admission.NewAttributesRecord(
attrs.GetObject(), attrs.GetObject(), attrs.GetKind(), attrs.GetNamespace(), attrs.GetName(),
attrs.GetResource(), "status", admission.Update, &metav1.UpdateOptions{}, false, nil)
}

View File

@ -24,6 +24,7 @@ import (
v1 "k8s.io/api/admission/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
"k8s.io/apiserver/pkg/authorization/authorizer"
)
var _ ExpressionAccessor = &MatchCondition{}
@ -49,19 +50,41 @@ func (v *MatchCondition) GetExpression() string {
return v.Expression
}
// OptionalVariableDeclarations declares which optional CEL variables
// are declared for an expression.
type OptionalVariableDeclarations struct {
// HasParams specifies if the "params" variable is declared.
// The "params" variable may still be bound to "null" when declared.
HasParams bool
// HasAuthorizer specifies if the"authorizer" and "authorizer.requestResource"
// variables are declared. When declared, the authorizer variables are
// expected to be non-null.
HasAuthorizer bool
}
// FilterCompiler contains a function to assist with converting types and values to/from CEL-typed values.
type FilterCompiler interface {
// Compile is used for the cel expression compilation
Compile(expressions []ExpressionAccessor, hasParam bool) Filter
Compile(expressions []ExpressionAccessor, optionalDecls OptionalVariableDeclarations) Filter
}
// OptionalVariableBindings provides expression bindings for optional CEL variables.
type OptionalVariableBindings struct {
// VersionedParams provides the "params" variable binding. This variable binding may
// be set to nil even when OptionalVariableDeclarations.HashParams is set to true.
VersionedParams runtime.Object
// Authorizer provides the authorizer used for the "authorizer" and
// "authorizer.requestResource" variable bindings. If the expression was compiled with
// OptionalVariableDeclarations.HasAuthorizer set to true this must be non-nil.
Authorizer authorizer.Authorizer
}
// Filter contains a function to evaluate compiled CEL-typed values
// It expects the inbound object to already have been converted to the version expected
// by the underlying CEL code (which is indicated by the match criteria of a policy definition).
// versionedParams may be nil.
type Filter interface {
// ForInput converts compiled CEL-typed values into evaluated CEL-typed values
ForInput(versionedAttr *generic.VersionedAttributes, versionedParams runtime.Object, request *v1.AdmissionRequest) ([]EvaluationResult, error)
ForInput(versionedAttr *generic.VersionedAttributes, request *v1.AdmissionRequest, optionalVars OptionalVariableBindings) ([]EvaluationResult, error)
// CompilationErrors returns a list of errors from the compilation of the evaluator
CompilationErrors() []error

View File

@ -23,6 +23,7 @@ import (
"io"
"k8s.io/apimachinery/pkg/api/meta"
"k8s.io/apiserver/pkg/authorization/authorizer"
"k8s.io/apiserver/pkg/features"
"k8s.io/client-go/dynamic"
"k8s.io/component-base/featuregate"
@ -71,6 +72,7 @@ type celAdmissionPlugin struct {
restMapper meta.RESTMapper
dynamicClient dynamic.Interface
stopCh <-chan struct{}
authorizer authorizer.Authorizer
}
var _ initializer.WantsExternalKubeInformerFactory = &celAdmissionPlugin{}
@ -78,6 +80,7 @@ var _ initializer.WantsExternalKubeClientSet = &celAdmissionPlugin{}
var _ initializer.WantsRESTMapper = &celAdmissionPlugin{}
var _ initializer.WantsDynamicClient = &celAdmissionPlugin{}
var _ initializer.WantsDrainedNotification = &celAdmissionPlugin{}
var _ initializer.WantsAuthorizer = &celAdmissionPlugin{}
var _ admission.InitializationValidator = &celAdmissionPlugin{}
var _ admission.ValidationInterface = &celAdmissionPlugin{}
@ -108,6 +111,10 @@ func (c *celAdmissionPlugin) SetDrainedNotification(stopCh <-chan struct{}) {
c.stopCh = stopCh
}
func (c *celAdmissionPlugin) SetAuthorizer(authorizer authorizer.Authorizer) {
c.authorizer = authorizer
}
func (c *celAdmissionPlugin) InspectFeatureGates(featureGates featuregate.FeatureGate) {
if featureGates.Enabled(features.ValidatingAdmissionPolicy) {
c.enabled = true
@ -138,7 +145,10 @@ func (c *celAdmissionPlugin) ValidateInitialization() error {
if c.stopCh == nil {
return errors.New("missing stop channel")
}
c.evaluator = NewAdmissionController(c.informerFactory, c.client, c.restMapper, c.dynamicClient)
if c.authorizer == nil {
return errors.New("missing authorizer")
}
c.evaluator = NewAdmissionController(c.informerFactory, c.client, c.restMapper, c.dynamicClient, c.authorizer)
if err := c.evaluator.ValidateInitialization(); err != nil {
return err
}

View File

@ -26,6 +26,8 @@ import (
"github.com/stretchr/testify/require"
"k8s.io/klog/v2"
admissionv1 "k8s.io/api/admission/v1"
admissionRegistrationv1 "k8s.io/api/admissionregistration/v1"
"k8s.io/api/admissionregistration/v1alpha1"
@ -42,6 +44,7 @@ import (
"k8s.io/apiserver/pkg/admission/plugin/cel"
"k8s.io/apiserver/pkg/admission/plugin/validatingadmissionpolicy/internal/generic"
whgeneric "k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
"k8s.io/apiserver/pkg/authorization/authorizer"
"k8s.io/apiserver/pkg/features"
dynamicfake "k8s.io/client-go/dynamic/fake"
"k8s.io/client-go/informers"
@ -49,7 +52,6 @@ import (
clienttesting "k8s.io/client-go/testing"
"k8s.io/client-go/tools/cache"
"k8s.io/component-base/featuregate"
"k8s.io/klog/v2"
)
var (
@ -158,7 +160,7 @@ var (
// Interface which has fake compile functionality for use in tests
// So that we can test the controller without pulling in any CEL functionality
type fakeCompiler struct {
CompileFuncs map[string]func([]cel.ExpressionAccessor, bool) cel.Filter
CompileFuncs map[string]func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter
}
var _ cel.FilterCompiler = &fakeCompiler{}
@ -169,22 +171,22 @@ func (f *fakeCompiler) HasSynced() bool {
func (f *fakeCompiler) Compile(
expressions []cel.ExpressionAccessor,
hasParam bool,
options cel.OptionalVariableDeclarations,
) cel.Filter {
key := expressions[0].GetExpression()
if fun, ok := f.CompileFuncs[key]; ok {
return fun(expressions, hasParam)
return fun(expressions, options)
}
return nil
}
func (f *fakeCompiler) RegisterDefinition(definition *v1alpha1.ValidatingAdmissionPolicy, compileFunc func([]cel.ExpressionAccessor, bool) cel.Filter) {
func (f *fakeCompiler) RegisterDefinition(definition *v1alpha1.ValidatingAdmissionPolicy, compileFunc func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter) {
//Key must be something that we can decipher from the inputs to Validate so using expression which will be passed to validate on the filter
key := definition.Spec.Validations[0].Expression
if compileFunc != nil {
if f.CompileFuncs == nil {
f.CompileFuncs = make(map[string]func([]cel.ExpressionAccessor, bool) cel.Filter)
f.CompileFuncs = make(map[string]func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter)
}
f.CompileFuncs[key] = compileFunc
}
@ -206,7 +208,7 @@ type fakeFilter struct {
keyId string
}
func (f *fakeFilter) ForInput(versionedAttr *whgeneric.VersionedAttributes, versionedParams runtime.Object, request *admissionv1.AdmissionRequest) ([]cel.EvaluationResult, error) {
func (f *fakeFilter) ForInput(versionedAttr *whgeneric.VersionedAttributes, request *admissionv1.AdmissionRequest, inputs cel.OptionalVariableBindings) ([]cel.EvaluationResult, error) {
return []cel.EvaluationResult{}, nil
}
@ -333,6 +335,7 @@ func setupTestCommon(t *testing.T, compiler cel.FilterCompiler, matcher Matcher,
testContext, testContextCancel := context.WithCancel(context.Background())
t.Cleanup(testContextCancel)
fakeAuthorizer := fakeAuthorizer{}
dynamicClient := dynamicfake.NewSimpleDynamicClient(scheme)
fakeClient := fake.NewSimpleClientset()
@ -355,7 +358,7 @@ func setupTestCommon(t *testing.T, compiler cel.FilterCompiler, matcher Matcher,
handler := plug.(*celAdmissionPlugin)
handler.enabled = true
genericInitializer := initializer.New(fakeClient, dynamicClient, fakeInformerFactory, nil, featureGate, testContext.Done())
genericInitializer := initializer.New(fakeClient, dynamicClient, fakeInformerFactory, fakeAuthorizer, featureGate, testContext.Done())
genericInitializer.Initialize(handler)
handler.SetRESTMapper(fakeRestMapper)
err = admission.ValidateInitialization(handler)
@ -365,7 +368,7 @@ func setupTestCommon(t *testing.T, compiler cel.FilterCompiler, matcher Matcher,
// Override compiler used by controller for tests
controller = handler.evaluator.(*celAdmissionController)
controller.policyController.filterCompiler = compiler
controller.policyController.newValidator = func(filter cel.Filter, fail *admissionRegistrationv1.FailurePolicyType) Validator {
controller.policyController.newValidator = func(filter cel.Filter, fail *admissionRegistrationv1.FailurePolicyType, authorizer authorizer.Authorizer) Validator {
f := filter.(*fakeFilter)
v := validatorMap[f.keyId]
v.fakeFilter = f
@ -702,7 +705,7 @@ func TestBasicPolicyDefinitionFailure(t *testing.T) {
DefaultMatch: true,
}
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
datalock.Lock()
numCompiles += 1
datalock.Unlock()
@ -762,7 +765,7 @@ func TestDefinitionDoesntMatch(t *testing.T) {
passedParams := []*unstructured.Unstructured{}
numCompiles := 0
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
datalock.Lock()
numCompiles += 1
datalock.Unlock()
@ -873,7 +876,7 @@ func TestReconfigureBinding(t *testing.T) {
},
}
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
datalock.Lock()
numCompiles += 1
datalock.Unlock()
@ -980,7 +983,7 @@ func TestRemoveDefinition(t *testing.T) {
datalock := sync.Mutex{}
numCompiles := 0
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
datalock.Lock()
numCompiles += 1
datalock.Unlock()
@ -1047,7 +1050,7 @@ func TestRemoveBinding(t *testing.T) {
datalock := sync.Mutex{}
numCompiles := 0
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
datalock.Lock()
numCompiles += 1
datalock.Unlock()
@ -1155,7 +1158,7 @@ func TestInvalidParamSourceInstanceName(t *testing.T) {
passedParams := []*unstructured.Unstructured{}
numCompiles := 0
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
datalock.Lock()
numCompiles += 1
datalock.Unlock()
@ -1221,7 +1224,7 @@ func TestEmptyParamSource(t *testing.T) {
noParamSourcePolicy := *denyPolicy
noParamSourcePolicy.Spec.ParamKind = nil
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(denyPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
datalock.Lock()
numCompiles += 1
datalock.Unlock()
@ -1323,7 +1326,7 @@ func TestMultiplePoliciesSharedParamType(t *testing.T) {
compiles2 := atomic.Int64{}
evaluations2 := atomic.Int64{}
compiler.RegisterDefinition(&policy1, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(&policy1, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
compiles1.Add(1)
return &fakeFilter{
@ -1340,7 +1343,7 @@ func TestMultiplePoliciesSharedParamType(t *testing.T) {
}
})
compiler.RegisterDefinition(&policy2, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(&policy2, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
compiles2.Add(1)
return &fakeFilter{
@ -1448,7 +1451,7 @@ func TestNativeTypeParam(t *testing.T) {
Kind: "ConfigMap",
}
compiler.RegisterDefinition(&nativeTypeParamPolicy, func([]cel.ExpressionAccessor, bool) cel.Filter {
compiler.RegisterDefinition(&nativeTypeParamPolicy, func([]cel.ExpressionAccessor, cel.OptionalVariableDeclarations) cel.Filter {
compiles.Add(1)
return &fakeFilter{
@ -1511,3 +1514,9 @@ func TestNativeTypeParam(t *testing.T) {
require.EqualValues(t, 1, compiles.Load())
require.EqualValues(t, 1, evaluations.Load())
}
type fakeAuthorizer struct{}
func (f fakeAuthorizer) Authorize(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
return authorizer.DecisionAllow, "", nil
}

View File

@ -38,6 +38,7 @@ import (
"k8s.io/apiserver/pkg/admission/plugin/validatingadmissionpolicy/internal/generic"
"k8s.io/apiserver/pkg/admission/plugin/validatingadmissionpolicy/matching"
whgeneric "k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
"k8s.io/apiserver/pkg/authorization/authorizer"
"k8s.io/client-go/dynamic"
"k8s.io/client-go/informers"
"k8s.io/client-go/kubernetes"
@ -119,6 +120,7 @@ func NewAdmissionController(
client kubernetes.Interface,
restMapper meta.RESTMapper,
dynamicClient dynamic.Interface,
authz authorizer.Authorizer,
) CELPolicyEvaluator {
return &celAdmissionController{
definitions: atomic.Value{},
@ -132,6 +134,7 @@ func NewAdmissionController(
informerFactory.Admissionregistration().V1alpha1().ValidatingAdmissionPolicies().Informer()),
generic.NewInformer[*v1alpha1.ValidatingAdmissionPolicyBinding](
informerFactory.Admissionregistration().V1alpha1().ValidatingAdmissionPolicyBindings().Informer()),
authz,
),
}
}

View File

@ -32,6 +32,7 @@ import (
celmetrics "k8s.io/apiserver/pkg/admission/cel"
"k8s.io/apiserver/pkg/admission/plugin/cel"
"k8s.io/apiserver/pkg/admission/plugin/validatingadmissionpolicy/internal/generic"
"k8s.io/apiserver/pkg/authorization/authorizer"
"k8s.io/client-go/dynamic"
"k8s.io/client-go/dynamic/dynamicinformer"
"k8s.io/client-go/informers"
@ -85,9 +86,11 @@ type policyController struct {
definitionsToBindings map[namespacedName]sets.Set[namespacedName]
client kubernetes.Interface
authz authorizer.Authorizer
}
type newValidator func(cel.Filter, *v1.FailurePolicyType) Validator
type newValidator func(cel.Filter, *v1.FailurePolicyType, authorizer.Authorizer) Validator
func newPolicyController(
restMapper meta.RESTMapper,
@ -97,6 +100,7 @@ func newPolicyController(
matcher Matcher,
policiesInformer generic.Informer[*v1alpha1.ValidatingAdmissionPolicy],
bindingsInformer generic.Informer[*v1alpha1.ValidatingAdmissionPolicyBinding],
authz authorizer.Authorizer,
) *policyController {
res := &policyController{}
*res = policyController{
@ -126,6 +130,7 @@ func newPolicyController(
restMapper: restMapper,
dynamicClient: dynamicClient,
client: client,
authz: authz,
}
return res
}
@ -439,9 +444,11 @@ func (c *policyController) latestPolicyData() []policyData {
if definitionInfo.lastReconciledValue.Spec.ParamKind != nil {
hasParam = true
}
optionalVars := cel.OptionalVariableDeclarations{HasParams: hasParam, HasAuthorizer: true}
bindingInfo.validator = c.newValidator(
c.filterCompiler.Compile(convertv1alpha1Validations(definitionInfo.lastReconciledValue.Spec.Validations), hasParam),
c.filterCompiler.Compile(convertv1alpha1Validations(definitionInfo.lastReconciledValue.Spec.Validations), optionalVars),
convertv1alpha1FailurePolicyTypeTov1FailurePolicyType(definitionInfo.lastReconciledValue.Spec.FailurePolicy),
c.authz,
)
}
bindingInfos = append(bindingInfos, *bindingInfo)

View File

@ -18,6 +18,7 @@ package validatingadmissionpolicy
import (
"context"
"k8s.io/apiserver/pkg/admission"
)

View File

@ -18,28 +18,31 @@ package validatingadmissionpolicy
import (
"fmt"
"k8s.io/klog/v2"
"strings"
celtypes "github.com/google/cel-go/common/types"
"k8s.io/klog/v2"
v1 "k8s.io/api/admissionregistration/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apiserver/pkg/admission/plugin/cel"
"k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
"k8s.io/apiserver/pkg/authorization/authorizer"
)
// validator implements the Validator interface
type validator struct {
filter cel.Filter
failPolicy *v1.FailurePolicyType
authorizer authorizer.Authorizer
}
func NewValidator(filter cel.Filter, failPolicy *v1.FailurePolicyType) Validator {
func NewValidator(filter cel.Filter, failPolicy *v1.FailurePolicyType, authorizer authorizer.Authorizer) Validator {
return &validator{
filter: filter,
failPolicy: failPolicy,
authorizer: authorizer,
}
}
@ -59,7 +62,8 @@ func (v *validator) Validate(versionedAttr *generic.VersionedAttributes, version
f = *v.failPolicy
}
evalResults, err := v.filter.ForInput(versionedAttr, versionedParams, cel.CreateAdmissionRequest(versionedAttr.Attributes))
optionalVars := cel.OptionalVariableBindings{VersionedParams: versionedParams, Authorizer: v.authorizer}
evalResults, err := v.filter.ForInput(versionedAttr, cel.CreateAdmissionRequest(versionedAttr.Attributes), optionalVars)
if err != nil {
return []PolicyDecision{
{

View File

@ -28,7 +28,6 @@ import (
admissionv1 "k8s.io/api/admission/v1"
v1 "k8s.io/api/admissionregistration/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apiserver/pkg/admission"
"k8s.io/apiserver/pkg/admission/plugin/cel"
@ -42,7 +41,7 @@ type fakeCelFilter struct {
throwError bool
}
func (f *fakeCelFilter) ForInput(versionedAttr *generic.VersionedAttributes, versionedParams runtime.Object, request *admissionv1.AdmissionRequest) ([]cel.EvaluationResult, error) {
func (f *fakeCelFilter) ForInput(*generic.VersionedAttributes, *admissionv1.AdmissionRequest, cel.OptionalVariableBindings) ([]cel.EvaluationResult, error) {
if f.throwError {
return nil, errors.New("test error")
}
@ -465,6 +464,7 @@ func TestValidate(t *testing.T) {
throwError: tc.throwError,
},
}
policyResults := v.Validate(fakeVersionedAttr, nil)
require.Equal(t, len(policyResults), len(tc.policyDecision))

580
pkg/cel/library/authz.go Normal file
View File

@ -0,0 +1,580 @@
/*
Copyright 2023 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package library
import (
"context"
"fmt"
"reflect"
"strings"
"github.com/google/cel-go/cel"
"github.com/google/cel-go/common/types"
"github.com/google/cel-go/common/types/ref"
apimachineryvalidation "k8s.io/apimachinery/pkg/api/validation"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apiserver/pkg/authentication/serviceaccount"
"k8s.io/apiserver/pkg/authentication/user"
"k8s.io/apiserver/pkg/authorization/authorizer"
)
// Authz provides a CEL function library extension for performing authorization checks.
// Note that authorization checks are only supported for CEL expression fields in the API
// where an 'authorizer' variable is provided to the CEL expression. See the
// documentation of API fields where CEL expressions are used to learn if the 'authorizer'
// variable is provided.
//
// path
//
// Returns a PathCheck configured to check authorization for a non-resource request
// path (e.g. /healthz). If path is an empty string, an error is returned.
// Note that the leading '/' is not required.
//
// <Authorizer>.path(<string>) <PathCheck>
//
// Examples:
//
// authorizer.path('/healthz') // returns a PathCheck for the '/healthz' API path
// authorizer.path('') // results in "path must not be empty" error
// authorizer.path(' ') // results in "path must not be empty" error
//
// group
//
// Returns a GroupCheck configured to check authorization for the API resources for
// a particular API group.
// Note that authorization checks are only supported for CEL expression fields in the API
// where an 'authorizer' variable is provided to the CEL expression. Check the
// documentation of API fields where CEL expressions are used to learn if the 'authorizer'
// variable is provided.
//
// <Authorizer>.group(<string>) <GroupCheck>
//
// Examples:
//
// authorizer.group('apps') // returns a GroupCheck for the 'apps' API group
// authorizer.group('') // returns a GroupCheck for the core API group
// authorizer.group('example.com') // returns a GroupCheck for the custom resources in the 'example.com' API group
//
// serviceAccount
//
// Returns an Authorizer configured to check authorization for the provided service account namespace and name.
// If the name is not a valid DNS subdomain string (as defined by RFC 1123), an error is returned.
// If the namespace is not a valid DNS label (as defined by RFC 1123), an error is returned.
//
// <Authorizer>.serviceAccount(<string>, <string>) <Authorizer>
//
// Examples:
//
// authorizer.serviceAccount('default', 'myserviceaccount') // returns an Authorizer for the service account with namespace 'default' and name 'myserviceaccount'
// authorizer.serviceAccount('not@a#valid!namespace', 'validname') // returns an error
// authorizer.serviceAccount('valid.example.com', 'invalid@*name') // returns an error
//
// resource
//
// Returns a ResourceCheck configured to check authorization for a particular API resource.
// Note that the provided resource string should be a lower case plural name of a Kubernetes API resource.
//
// <GroupCheck>.resource(<string>) <ResourceCheck>
//
// Examples:
//
// authorizer.group('apps').resource('deployments') // returns a ResourceCheck for the 'deployments' resources in the 'apps' group.
// authorizer.group('').resource('pods') // returns a ResourceCheck for the 'pods' resources in the core group.
// authorizer.group('apps').resource('') // results in "resource must not be empty" error
// authorizer.group('apps').resource(' ') // results in "resource must not be empty" error
//
// subresource
//
// Returns a ResourceCheck configured to check authorization for a particular subresource of an API resource.
// If subresource is set to "", the subresource field of this ResourceCheck is considered unset.
//
// <ResourceCheck>.subresource(<string>) <ResourceCheck>
//
// Examples:
//
// authorizer.group('').resource('pods').subresource('status') // returns a ResourceCheck the 'status' subresource of 'pods'
// authorizer.group('apps').resource('deployments').subresource('scale') // returns a ResourceCheck the 'scale' subresource of 'deployments'
// authorizer.group('example.com').resource('widgets').subresource('scale') // returns a ResourceCheck for the 'scale' subresource of the 'widgets' custom resource
// authorizer.group('example.com').resource('widgets').subresource('') // returns a ResourceCheck for the 'widgets' resource.
//
// namespace
//
// Returns a ResourceCheck configured to check authorization for a particular namespace.
// For cluster scoped resources, namespace() does not need to be called; namespace defaults
// to "", which is the correct namespace value to use to check cluster scoped resources.
// If namespace is set to "", the ResourceCheck will check authorization for the cluster scope.
//
// <ResourceCheck>.namespace(<string>) <ResourceCheck>
//
// Examples:
//
// authorizer.group('apps').resource('deployments').namespace('test') // returns a ResourceCheck for 'deployments' in the 'test' namespace
// authorizer.group('').resource('pods').namespace('default') // returns a ResourceCheck for 'pods' in the 'default' namespace
// authorizer.group('').resource('widgets').namespace('') // returns a ResourceCheck for 'widgets' in the cluster scope
//
// name
//
// Returns a ResourceCheck configured to check authorization for a particular resource name.
// If name is set to "", the name field of this ResourceCheck is considered unset.
//
// <ResourceCheck>.name(<name>) <ResourceCheck>
//
// Examples:
//
// authorizer.group('apps').resource('deployments').namespace('test').name('backend') // returns a ResourceCheck for the 'backend' 'deployments' resource in the 'test' namespace
// authorizer.group('apps').resource('deployments').namespace('test').name('') // returns a ResourceCheck for the 'deployments' resource in the 'test' namespace
//
// check
//
// For PathCheck, checks if the principal (user or service account) that sent the request is authorized for the HTTP request verb of the path.
// For ResourceCheck, checks if the principal (user or service account) that sent the request is authorized for the API verb and the configured authorization checks of the ResourceCheck.
// The check operation can be expensive, particularly in clusters using the webhook authorization mode.
//
// <PathCheck>.check(<check>) <Decision>
// <ResourceCheck>.check(<check>) <Decision>
//
// Examples:
//
// authorizer.group('').resource('pods').namespace('default').check('create') // Checks if the principal (user or service account) is authorized create pods in the 'default' namespace.
// authorizer.path('/healthz').check('get') // Checks if the principal (user or service account) is authorized to make HTTP GET requests to the /healthz API path.
//
// allowed
//
// Returns true if the authorizer's decision for the check is "allow". Note that if the authorizer's decision is
// "no opinion", that both the 'allowed' and 'denied' functions will return false.
//
// <Decision>.allowed() <bool>
//
// Examples:
//
// authorizer.group('').resource('pods').namespace('default').check('create').allowed() // Returns true if the principal (user or service account) is allowed create pods in the 'default' namespace.
// authorizer.path('/healthz').check('get').allowed() // Returns true if the principal (user or service account) is allowed to make HTTP GET requests to the /healthz API path.
//
// reason
//
// Returns a string reason for the authorization decision
//
// <Decision>.reason() <string>
//
// Examples:
//
// authorizer.path('/healthz').check('GET').reason()
func Authz() cel.EnvOption {
return cel.Lib(authzLib)
}
var authzLib = &authz{}
type authz struct{}
var authzLibraryDecls = map[string][]cel.FunctionOpt{
"path": {
cel.MemberOverload("authorizer_path", []*cel.Type{AuthorizerType, cel.StringType}, PathCheckType,
cel.BinaryBinding(authorizerPath))},
"group": {
cel.MemberOverload("authorizer_group", []*cel.Type{AuthorizerType, cel.StringType}, GroupCheckType,
cel.BinaryBinding(authorizerGroup))},
"serviceAccount": {
cel.MemberOverload("authorizer_serviceaccount", []*cel.Type{AuthorizerType, cel.StringType, cel.StringType}, AuthorizerType,
cel.FunctionBinding(authorizerServiceAccount))},
"resource": {
cel.MemberOverload("groupcheck_resource", []*cel.Type{GroupCheckType, cel.StringType}, ResourceCheckType,
cel.BinaryBinding(groupCheckResource))},
"subresource": {
cel.MemberOverload("resourcecheck_subresource", []*cel.Type{ResourceCheckType, cel.StringType}, ResourceCheckType,
cel.BinaryBinding(resourceCheckSubresource))},
"namespace": {
cel.MemberOverload("resourcecheck_namespace", []*cel.Type{ResourceCheckType, cel.StringType}, ResourceCheckType,
cel.BinaryBinding(resourceCheckNamespace))},
"name": {
cel.MemberOverload("resourcecheck_name", []*cel.Type{ResourceCheckType, cel.StringType}, ResourceCheckType,
cel.BinaryBinding(resourceCheckName))},
"check": {
cel.MemberOverload("pathcheck_check", []*cel.Type{PathCheckType, cel.StringType}, DecisionType,
cel.BinaryBinding(pathCheckCheck)),
cel.MemberOverload("resourcecheck_check", []*cel.Type{ResourceCheckType, cel.StringType}, DecisionType,
cel.BinaryBinding(resourceCheckCheck))},
"allowed": {
cel.MemberOverload("decision_allowed", []*cel.Type{DecisionType}, cel.BoolType,
cel.UnaryBinding(decisionAllowed))},
"reason": {
cel.MemberOverload("decision_reason", []*cel.Type{DecisionType}, cel.StringType,
cel.UnaryBinding(decisionReason))},
}
func (*authz) CompileOptions() []cel.EnvOption {
options := make([]cel.EnvOption, 0, len(authzLibraryDecls))
for name, overloads := range authzLibraryDecls {
options = append(options, cel.Function(name, overloads...))
}
return options
}
func (*authz) ProgramOptions() []cel.ProgramOption {
return []cel.ProgramOption{}
}
func authorizerPath(arg1, arg2 ref.Val) ref.Val {
authz, ok := arg1.(authorizerVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
path, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
if len(strings.TrimSpace(path)) == 0 {
return types.NewErr("path must not be empty")
}
return authz.pathCheck(path)
}
func authorizerGroup(arg1, arg2 ref.Val) ref.Val {
authz, ok := arg1.(authorizerVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
group, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
return authz.groupCheck(group)
}
func authorizerServiceAccount(args ...ref.Val) ref.Val {
argn := len(args)
if argn != 3 {
return types.NoSuchOverloadErr()
}
authz, ok := args[0].(authorizerVal)
if !ok {
return types.MaybeNoSuchOverloadErr(args[0])
}
namespace, ok := args[1].Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(args[1])
}
name, ok := args[2].Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(args[2])
}
if errors := apimachineryvalidation.ValidateServiceAccountName(name, false); len(errors) > 0 {
return types.NewErr("Invalid service account name")
}
if errors := apimachineryvalidation.ValidateNamespaceName(namespace, false); len(errors) > 0 {
return types.NewErr("Invalid service account namespace")
}
return authz.serviceAccount(namespace, name)
}
func groupCheckResource(arg1, arg2 ref.Val) ref.Val {
groupCheck, ok := arg1.(groupCheckVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
resource, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
if len(strings.TrimSpace(resource)) == 0 {
return types.NewErr("resource must not be empty")
}
return groupCheck.resourceCheck(resource)
}
func resourceCheckSubresource(arg1, arg2 ref.Val) ref.Val {
resourceCheck, ok := arg1.(resourceCheckVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
subresource, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
result := resourceCheck
result.subresource = subresource
return result
}
func resourceCheckNamespace(arg1, arg2 ref.Val) ref.Val {
resourceCheck, ok := arg1.(resourceCheckVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
namespace, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
result := resourceCheck
result.namespace = namespace
return result
}
func resourceCheckName(arg1, arg2 ref.Val) ref.Val {
resourceCheck, ok := arg1.(resourceCheckVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
name, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
result := resourceCheck
result.name = name
return result
}
func pathCheckCheck(arg1, arg2 ref.Val) ref.Val {
pathCheck, ok := arg1.(pathCheckVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
httpRequestVerb, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
return pathCheck.Authorize(context.TODO(), httpRequestVerb)
}
func resourceCheckCheck(arg1, arg2 ref.Val) ref.Val {
resourceCheck, ok := arg1.(resourceCheckVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
apiVerb, ok := arg2.Value().(string)
if !ok {
return types.MaybeNoSuchOverloadErr(arg1)
}
return resourceCheck.Authorize(context.TODO(), apiVerb)
}
func decisionAllowed(arg ref.Val) ref.Val {
decision, ok := arg.(decisionVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg)
}
return types.Bool(decision.authDecision == authorizer.DecisionAllow)
}
func decisionReason(arg ref.Val) ref.Val {
decision, ok := arg.(decisionVal)
if !ok {
return types.MaybeNoSuchOverloadErr(arg)
}
return types.String(decision.reason)
}
var (
AuthorizerType = cel.ObjectType("kubernetes.authorization.Authorizer")
PathCheckType = cel.ObjectType("kubernetes.authorization.PathCheck")
GroupCheckType = cel.ObjectType("kubernetes.authorization.GroupCheck")
ResourceCheckType = cel.ObjectType("kubernetes.authorization.ResourceCheck")
DecisionType = cel.ObjectType("kubernetes.authorization.Decision")
)
// Resource represents an API resource
type Resource interface {
// GetName returns the name of the object as presented in the request. On a CREATE operation, the client
// may omit name and rely on the server to generate the name. If that is the case, this method will return
// the empty string
GetName() string
// GetNamespace is the namespace associated with the request (if any)
GetNamespace() string
// GetResource is the name of the resource being requested. This is not the kind. For example: pods
GetResource() schema.GroupVersionResource
// GetSubresource is the name of the subresource being requested. This is a different resource, scoped to the parent resource, but it may have a different kind.
// For instance, /pods has the resource "pods" and the kind "Pod", while /pods/foo/status has the resource "pods", the sub resource "status", and the kind "Pod"
// (because status operates on pods). The binding resource for a pod though may be /pods/foo/binding, which has resource "pods", subresource "binding", and kind "Binding".
GetSubresource() string
}
func NewAuthorizerVal(userInfo user.Info, authorizer authorizer.Authorizer) ref.Val {
return authorizerVal{receiverOnlyObjectVal: receiverOnlyVal(AuthorizerType), userInfo: userInfo, authAuthorizer: authorizer}
}
func NewResourceAuthorizerVal(userInfo user.Info, authorizer authorizer.Authorizer, requestResource Resource) ref.Val {
a := authorizerVal{receiverOnlyObjectVal: receiverOnlyVal(AuthorizerType), userInfo: userInfo, authAuthorizer: authorizer}
resource := requestResource.GetResource()
g := a.groupCheck(resource.Group)
r := g.resourceCheck(resource.Resource)
r.subresource = requestResource.GetSubresource()
r.namespace = requestResource.GetNamespace()
r.name = requestResource.GetName()
return r
}
type authorizerVal struct {
receiverOnlyObjectVal
userInfo user.Info
authAuthorizer authorizer.Authorizer
}
func (a authorizerVal) pathCheck(path string) pathCheckVal {
return pathCheckVal{receiverOnlyObjectVal: receiverOnlyVal(PathCheckType), authorizer: a, path: path}
}
func (a authorizerVal) groupCheck(group string) groupCheckVal {
return groupCheckVal{receiverOnlyObjectVal: receiverOnlyVal(GroupCheckType), authorizer: a, group: group}
}
func (a authorizerVal) serviceAccount(namespace, name string) authorizerVal {
sa := &serviceaccount.ServiceAccountInfo{Name: name, Namespace: namespace}
return authorizerVal{
receiverOnlyObjectVal: receiverOnlyVal(AuthorizerType),
userInfo: sa.UserInfo(),
authAuthorizer: a.authAuthorizer,
}
}
type pathCheckVal struct {
receiverOnlyObjectVal
authorizer authorizerVal
path string
}
func (a pathCheckVal) Authorize(ctx context.Context, verb string) ref.Val {
attr := &authorizer.AttributesRecord{
Path: a.path,
Verb: verb,
User: a.authorizer.userInfo,
}
decision, reason, err := a.authorizer.authAuthorizer.Authorize(ctx, attr)
if err != nil {
return types.NewErr("error in authorization check: %v", err)
}
return newDecision(decision, reason)
}
type groupCheckVal struct {
receiverOnlyObjectVal
authorizer authorizerVal
group string
}
func (g groupCheckVal) resourceCheck(resource string) resourceCheckVal {
return resourceCheckVal{receiverOnlyObjectVal: receiverOnlyVal(ResourceCheckType), groupCheck: g, resource: resource}
}
type resourceCheckVal struct {
receiverOnlyObjectVal
groupCheck groupCheckVal
resource string
subresource string
namespace string
name string
}
func (a resourceCheckVal) Authorize(ctx context.Context, verb string) ref.Val {
attr := &authorizer.AttributesRecord{
ResourceRequest: true,
APIGroup: a.groupCheck.group,
APIVersion: "*",
Resource: a.resource,
Subresource: a.subresource,
Namespace: a.namespace,
Name: a.name,
Verb: verb,
User: a.groupCheck.authorizer.userInfo,
}
decision, reason, err := a.groupCheck.authorizer.authAuthorizer.Authorize(ctx, attr)
if err != nil {
return types.NewErr("error in authorization check: %v", err)
}
return newDecision(decision, reason)
}
func newDecision(authDecision authorizer.Decision, reason string) decisionVal {
return decisionVal{receiverOnlyObjectVal: receiverOnlyVal(DecisionType), authDecision: authDecision, reason: reason}
}
type decisionVal struct {
receiverOnlyObjectVal
authDecision authorizer.Decision
reason string
}
// receiverOnlyObjectVal provides an implementation of ref.Val for
// any object type that has receiver functions but does not expose any fields to
// CEL.
type receiverOnlyObjectVal struct {
typeValue *types.TypeValue
}
// receiverOnlyVal returns a receiverOnlyObjectVal for the given type.
func receiverOnlyVal(objectType *cel.Type) receiverOnlyObjectVal {
return receiverOnlyObjectVal{typeValue: types.NewTypeValue(objectType.String())}
}
// ConvertToNative implements ref.Val.ConvertToNative.
func (a receiverOnlyObjectVal) ConvertToNative(typeDesc reflect.Type) (any, error) {
return nil, fmt.Errorf("type conversion error from '%s' to '%v'", a.typeValue.String(), typeDesc)
}
// ConvertToType implements ref.Val.ConvertToType.
func (a receiverOnlyObjectVal) ConvertToType(typeVal ref.Type) ref.Val {
switch typeVal {
case a.typeValue:
return a
case types.TypeType:
return a.typeValue
}
return types.NewErr("type conversion error from '%s' to '%s'", a.typeValue, typeVal)
}
// Equal implements ref.Val.Equal.
func (a receiverOnlyObjectVal) Equal(other ref.Val) ref.Val {
o, ok := other.(receiverOnlyObjectVal)
if !ok {
return types.MaybeNoSuchOverloadErr(other)
}
return types.Bool(a == o)
}
// Type implements ref.Val.Type.
func (a receiverOnlyObjectVal) Type() ref.Type {
return a.typeValue
}
// Value implements ref.Val.Value.
func (a receiverOnlyObjectVal) Value() any {
return types.NoSuchOverloadErr()
}

View File

@ -36,6 +36,15 @@ type CostEstimator struct {
func (l *CostEstimator) CallCost(function, overloadId string, args []ref.Val, result ref.Val) *uint64 {
switch function {
case "check":
// An authorization check has a fixed cost
// This cost is set to allow for only two authorization checks per expression
cost := uint64(350000)
return &cost
case "serviceAccount", "path", "group", "resource", "subresource", "namespace", "name", "allowed", "denied", "reason":
// All authorization builder and accessor functions have a nominal cost
cost := uint64(1)
return &cost
case "isSorted", "sum", "max", "min", "indexOf", "lastIndexOf":
var cost uint64
if len(args) > 0 {
@ -78,6 +87,13 @@ func (l *CostEstimator) EstimateCallCost(function, overloadId string, target *ch
// WARNING: Any changes to this code impact API compatibility! The estimated cost is used to determine which CEL rules may be written to a
// CRD and any change (cost increases and cost decreases) are breaking.
switch function {
case "check":
// An authorization check has a fixed cost
// This cost is set to allow for only two authorization checks per expression
return &checker.CallEstimate{CostEstimate: checker.CostEstimate{Min: 350000, Max: 350000}}
case "serviceAccount", "path", "group", "resource", "subresource", "namespace", "name", "allowed", "denied", "reason":
// All authorization builder and accessor functions have a nominal cost
return &checker.CallEstimate{CostEstimate: checker.CostEstimate{Min: 1, Max: 1}}
case "isSorted", "sum", "max", "min", "indexOf", "lastIndexOf":
if target != nil {
// Charge 1 cost for comparing each element in the list
@ -94,7 +110,6 @@ func (l *CostEstimator) EstimateCallCost(function, overloadId string, target *ch
} else { // the target is a string, which is supported by indexOf and lastIndexOf
return &checker.CallEstimate{CostEstimate: l.sizeEstimate(*target).MultiplyByCostFactor(common.StringTraversalCostFactor)}
}
}
case "url":
if len(args) == 1 {

View File

@ -17,6 +17,7 @@ limitations under the License.
package library
import (
"context"
"fmt"
"testing"
@ -24,6 +25,8 @@ import (
"github.com/google/cel-go/checker"
"github.com/google/cel-go/ext"
expr "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
"k8s.io/apiserver/pkg/authorization/authorizer"
)
const (
@ -311,12 +314,62 @@ func TestStringLibrary(t *testing.T) {
}
}
func TestAuthzLibrary(t *testing.T) {
cases := []struct {
name string
expr string
expectEstimatedCost checker.CostEstimate
expectRuntimeCost uint64
}{
{
name: "path",
expr: "authorizer.path('/healthz')",
expectEstimatedCost: checker.CostEstimate{Min: 2, Max: 2},
expectRuntimeCost: 2,
},
{
name: "resource",
expr: "authorizer.group('apps').resource('deployments').subresource('status').namespace('test').name('backend')",
expectEstimatedCost: checker.CostEstimate{Min: 6, Max: 6},
expectRuntimeCost: 6,
},
{
name: "path check allowed",
expr: "authorizer.path('/healthz').check('get').allowed()",
expectEstimatedCost: checker.CostEstimate{Min: 350003, Max: 350003},
expectRuntimeCost: 350003,
},
{
name: "resource check allowed",
expr: "authorizer.group('apps').resource('deployments').subresource('status').namespace('test').name('backend').check('create').allowed()",
expectEstimatedCost: checker.CostEstimate{Min: 350007, Max: 350007},
expectRuntimeCost: 350007,
},
{
name: "resource check reason",
expr: "authorizer.group('apps').resource('deployments').subresource('status').namespace('test').name('backend').check('create').allowed()",
expectEstimatedCost: checker.CostEstimate{Min: 350007, Max: 350007},
expectRuntimeCost: 350007,
},
}
for _, tc := range cases {
t.Run(tc.name, func(t *testing.T) {
testCost(t, tc.expr, tc.expectEstimatedCost, tc.expectRuntimeCost)
})
}
}
func testCost(t *testing.T, expr string, expectEsimatedCost checker.CostEstimate, expectRuntimeCost uint64) {
est := &CostEstimator{SizeEstimator: &testCostEstimator{}}
env, err := cel.NewEnv(append(k8sExtensionLibs, ext.Strings())...)
if err != nil {
t.Fatalf("%v", err)
}
env, err = env.Extend(cel.Variable("authorizer", AuthorizerType))
if err != nil {
t.Fatalf("%v", err)
}
compiled, issues := env.Compile(expr)
if len(issues.Errors()) > 0 {
t.Fatalf("%v", issues.Errors())
@ -332,7 +385,7 @@ func testCost(t *testing.T, expr string, expectEsimatedCost checker.CostEstimate
if err != nil {
t.Fatalf("%v", err)
}
_, details, err := prog.Eval(map[string]interface{}{})
_, details, err := prog.Eval(map[string]interface{}{"authorizer": NewAuthorizerVal(nil, alwaysAllowAuthorizer{})})
if err != nil {
t.Fatalf("%v", err)
}
@ -361,3 +414,9 @@ func (t *testCostEstimator) EstimateSize(element checker.AstNode) *checker.SizeE
func (t *testCostEstimator) EstimateCallCost(function, overloadId string, target *checker.AstNode, args []checker.AstNode) *checker.CallEstimate {
return nil
}
type alwaysAllowAuthorizer struct{}
func (f alwaysAllowAuthorizer) Authorize(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
return authorizer.DecisionAllow, "", nil
}

View File

@ -29,6 +29,7 @@ var k8sExtensionLibs = []cel.EnvOption{
URLs(),
Regex(),
Lists(),
Authz(),
}
var ExtensionLibRegexOptimizations = []*interpreter.RegexOptimization{FindRegexOptimization, FindAllRegexOptimization}

View File

@ -29,6 +29,7 @@ func TestLibraryCompatibility(t *testing.T) {
urlsLib: urlLibraryDecls,
listsLib: listsLibraryDecls,
regexLib: regexLibraryDecls,
authzLib: authzLibraryDecls,
}
if len(k8sExtensionLibs) != len(decls) {
t.Errorf("Expected the same number of libraries in the ExtensionLibs as are tested for compatibility")
@ -46,6 +47,8 @@ func TestLibraryCompatibility(t *testing.T) {
// Kubernetes 1.24:
"isSorted", "sum", "max", "min", "indexOf", "lastIndexOf", "find", "findAll", "url", "getScheme", "getHost", "getHostname",
"getPort", "getEscapedPath", "getQuery", "isURL",
// Kubernetes <1.27>:
"path", "group", "serviceAccount", "resource", "subresource", "namespace", "name", "check", "allowed", "denied", "reason",
// Kubernetes <1.??>:
}
for _, fn := range knownFunctions {