385 lines
12 KiB
Go
385 lines
12 KiB
Go
/*
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*
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* Copyright 2020 The KubeSphere Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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* /
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*/
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package authorizerfactory
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import (
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"bytes"
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"fmt"
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"k8s.io/apiserver/pkg/authentication/serviceaccount"
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iamv1alpha2 "kubesphere.io/kubesphere/pkg/apis/iam/v1alpha2"
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"kubesphere.io/kubesphere/pkg/apiserver/authorization/authorizer"
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"kubesphere.io/kubesphere/pkg/models/iam/am"
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"kubesphere.io/kubesphere/pkg/utils/sliceutil"
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"k8s.io/klog"
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rbacv1 "k8s.io/api/rbac/v1"
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utilerrors "k8s.io/apimachinery/pkg/util/errors"
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"k8s.io/apiserver/pkg/authentication/user"
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rbacv1helpers "kubesphere.io/kubesphere/pkg/apis/rbac/v1"
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)
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type RBACAuthorizer struct {
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am am.AccessManagementInterface
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}
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// authorizingVisitor short-circuits once allowed, and collects any resolution errors encountered
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type authorizingVisitor struct {
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requestAttributes authorizer.Attributes
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allowed bool
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reason string
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errors []error
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}
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func (v *authorizingVisitor) visit(source fmt.Stringer, rule *rbacv1.PolicyRule, err error) bool {
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if rule != nil && ruleAllows(v.requestAttributes, rule) {
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v.allowed = true
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v.reason = fmt.Sprintf("RBAC: allowed by %s", source.String())
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return false
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}
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if err != nil {
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v.errors = append(v.errors, err)
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}
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return true
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}
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type ruleAccumulator struct {
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rules []rbacv1.PolicyRule
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errors []error
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}
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func (r *ruleAccumulator) visit(source fmt.Stringer, rule *rbacv1.PolicyRule, err error) bool {
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if rule != nil {
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r.rules = append(r.rules, *rule)
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}
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if err != nil {
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r.errors = append(r.errors, err)
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}
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return true
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}
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func (r *RBACAuthorizer) Authorize(requestAttributes authorizer.Attributes) (authorizer.Decision, string, error) {
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ruleCheckingVisitor := &authorizingVisitor{requestAttributes: requestAttributes}
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r.visitRulesFor(requestAttributes, ruleCheckingVisitor.visit)
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if ruleCheckingVisitor.allowed {
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return authorizer.DecisionAllow, ruleCheckingVisitor.reason, nil
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}
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// Build a detailed log of the denial.
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// Make the whole block conditional so we don't do a lot of string-building we won't use.
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if klog.V(4) {
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var operation string
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if requestAttributes.IsResourceRequest() {
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b := &bytes.Buffer{}
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b.WriteString(`"`)
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b.WriteString(requestAttributes.GetVerb())
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b.WriteString(`" resource "`)
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b.WriteString(requestAttributes.GetResource())
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if len(requestAttributes.GetAPIGroup()) > 0 {
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b.WriteString(`.`)
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b.WriteString(requestAttributes.GetAPIGroup())
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}
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if len(requestAttributes.GetSubresource()) > 0 {
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b.WriteString(`/`)
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b.WriteString(requestAttributes.GetSubresource())
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}
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b.WriteString(`"`)
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if len(requestAttributes.GetName()) > 0 {
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b.WriteString(` named "`)
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b.WriteString(requestAttributes.GetName())
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b.WriteString(`"`)
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}
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operation = b.String()
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} else {
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operation = fmt.Sprintf("%q nonResourceURL %q", requestAttributes.GetVerb(), requestAttributes.GetPath())
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}
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var scope string
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if ns := requestAttributes.GetNamespace(); len(ns) > 0 {
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scope = fmt.Sprintf("in namespace %q", ns)
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} else if ws := requestAttributes.GetWorkspace(); len(ws) > 0 {
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scope = fmt.Sprintf("in workspace %q", ws)
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} else if cluster := requestAttributes.GetWorkspace(); len(cluster) > 0 {
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scope = fmt.Sprintf("in cluster %q", cluster)
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} else {
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scope = "global-wide"
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}
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klog.Infof("RBAC: no rules authorize user %q with groups %q to %s %s", requestAttributes.GetUser().GetName(), requestAttributes.GetUser().GetGroups(), operation, scope)
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}
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reason := ""
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if len(ruleCheckingVisitor.errors) > 0 {
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reason = fmt.Sprintf("RBAC: %v", utilerrors.NewAggregate(ruleCheckingVisitor.errors))
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}
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return authorizer.DecisionNoOpinion, reason, nil
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}
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func NewRBACAuthorizer(am am.AccessManagementInterface) *RBACAuthorizer {
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return &RBACAuthorizer{am: am}
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}
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func ruleAllows(requestAttributes authorizer.Attributes, rule *rbacv1.PolicyRule) bool {
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if requestAttributes.IsResourceRequest() {
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combinedResource := requestAttributes.GetResource()
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if len(requestAttributes.GetSubresource()) > 0 {
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combinedResource = requestAttributes.GetResource() + "/" + requestAttributes.GetSubresource()
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}
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return rbacv1helpers.VerbMatches(rule, requestAttributes.GetVerb()) &&
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rbacv1helpers.APIGroupMatches(rule, requestAttributes.GetAPIGroup()) &&
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rbacv1helpers.ResourceMatches(rule, combinedResource, requestAttributes.GetSubresource()) &&
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rbacv1helpers.ResourceNameMatches(rule, requestAttributes.GetName())
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}
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return rbacv1helpers.VerbMatches(rule, requestAttributes.GetVerb()) &&
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rbacv1helpers.NonResourceURLMatches(rule, requestAttributes.GetPath())
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}
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func (r *RBACAuthorizer) rulesFor(requestAttributes authorizer.Attributes) ([]rbacv1.PolicyRule, error) {
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visitor := &ruleAccumulator{}
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r.visitRulesFor(requestAttributes, visitor.visit)
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return visitor.rules, utilerrors.NewAggregate(visitor.errors)
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}
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func (r *RBACAuthorizer) visitRulesFor(requestAttributes authorizer.Attributes, visitor func(source fmt.Stringer, rule *rbacv1.PolicyRule, err error) bool) {
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if globalRoleBindings, err := r.am.ListGlobalRoleBindings(""); err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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} else {
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sourceDescriber := &globalRoleBindingDescriber{}
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for _, globalRoleBinding := range globalRoleBindings {
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subjectIndex, applies := appliesTo(requestAttributes.GetUser(), globalRoleBinding.Subjects, "")
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if !applies {
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continue
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}
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rules, err := r.am.GetRoleReferenceRules(globalRoleBinding.RoleRef, "")
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if err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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continue
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}
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sourceDescriber.binding = globalRoleBinding
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sourceDescriber.subject = &globalRoleBinding.Subjects[subjectIndex]
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for i := range rules {
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if !visitor(sourceDescriber, &rules[i], nil) {
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return
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}
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}
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}
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}
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if requestAttributes.GetResourceScope() == iamv1alpha2.WorkspaceScope {
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if workspaceRoleBindings, err := r.am.ListWorkspaceRoleBindings("", requestAttributes.GetWorkspace()); err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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} else {
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sourceDescriber := &workspaceRoleBindingDescriber{}
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for _, workspaceRoleBinding := range workspaceRoleBindings {
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subjectIndex, applies := appliesTo(requestAttributes.GetUser(), workspaceRoleBinding.Subjects, "")
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if !applies {
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continue
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}
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rules, err := r.am.GetRoleReferenceRules(workspaceRoleBinding.RoleRef, "")
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if err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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continue
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}
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sourceDescriber.binding = workspaceRoleBinding
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sourceDescriber.subject = &workspaceRoleBinding.Subjects[subjectIndex]
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for i := range rules {
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if !visitor(sourceDescriber, &rules[i], nil) {
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return
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}
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}
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}
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}
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}
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if requestAttributes.GetResourceScope() == iamv1alpha2.NamespaceScope {
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if roleBindings, err := r.am.ListRoleBindings("", requestAttributes.GetNamespace()); err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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} else {
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sourceDescriber := &roleBindingDescriber{}
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for _, roleBinding := range roleBindings {
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subjectIndex, applies := appliesTo(requestAttributes.GetUser(), roleBinding.Subjects, requestAttributes.GetNamespace())
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if !applies {
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continue
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}
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rules, err := r.am.GetRoleReferenceRules(roleBinding.RoleRef, requestAttributes.GetNamespace())
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if err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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continue
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}
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sourceDescriber.binding = roleBinding
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sourceDescriber.subject = &roleBinding.Subjects[subjectIndex]
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for i := range rules {
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if !visitor(sourceDescriber, &rules[i], nil) {
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return
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}
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}
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}
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}
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}
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if clusterRoleBindings, err := r.am.ListClusterRoleBindings(""); err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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} else {
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sourceDescriber := &clusterRoleBindingDescriber{}
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for _, clusterRoleBinding := range clusterRoleBindings {
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subjectIndex, applies := appliesTo(requestAttributes.GetUser(), clusterRoleBinding.Subjects, "")
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if !applies {
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continue
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}
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rules, err := r.am.GetRoleReferenceRules(clusterRoleBinding.RoleRef, "")
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if err != nil {
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if !visitor(nil, nil, err) {
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return
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}
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continue
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}
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sourceDescriber.binding = clusterRoleBinding
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sourceDescriber.subject = &clusterRoleBinding.Subjects[subjectIndex]
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for i := range rules {
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if !visitor(sourceDescriber, &rules[i], nil) {
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return
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}
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}
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}
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}
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}
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// appliesTo returns whether any of the bindingSubjects applies to the specified subject,
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// and if true, the index of the first subject that applies
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func appliesTo(user user.Info, bindingSubjects []rbacv1.Subject, namespace string) (int, bool) {
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for i, bindingSubject := range bindingSubjects {
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if appliesToUser(user, bindingSubject, namespace) {
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return i, true
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}
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}
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return 0, false
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}
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func appliesToUser(user user.Info, subject rbacv1.Subject, namespace string) bool {
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switch subject.Kind {
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case rbacv1.UserKind:
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return user.GetName() == subject.Name
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case rbacv1.GroupKind:
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return sliceutil.HasString(user.GetGroups(), subject.Name)
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case rbacv1.ServiceAccountKind:
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// default the namespace to namespace we're working in if its available. This allows rolebindings that reference
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// SAs in th local namespace to avoid having to qualify them.
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saNamespace := namespace
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if len(subject.Namespace) > 0 {
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saNamespace = subject.Namespace
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}
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if len(saNamespace) == 0 {
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return false
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}
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// use a more efficient comparison for RBAC checking
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return serviceaccount.MatchesUsername(saNamespace, subject.Name, user.GetName())
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default:
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return false
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}
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}
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type globalRoleBindingDescriber struct {
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binding *iamv1alpha2.GlobalRoleBinding
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subject *rbacv1.Subject
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}
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func (d *globalRoleBindingDescriber) String() string {
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return fmt.Sprintf("GlobalRoleBinding %q of %s %q to %s",
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d.binding.Name,
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d.binding.RoleRef.Kind,
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d.binding.RoleRef.Name,
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describeSubject(d.subject, ""),
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)
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}
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type clusterRoleBindingDescriber struct {
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binding *rbacv1.ClusterRoleBinding
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subject *rbacv1.Subject
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}
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func (d *clusterRoleBindingDescriber) String() string {
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return fmt.Sprintf("ClusterRoleBinding %q of %s %q to %s",
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d.binding.Name,
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d.binding.RoleRef.Kind,
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d.binding.RoleRef.Name,
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describeSubject(d.subject, ""),
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)
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}
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type workspaceRoleBindingDescriber struct {
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binding *iamv1alpha2.WorkspaceRoleBinding
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subject *rbacv1.Subject
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}
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func (d *workspaceRoleBindingDescriber) String() string {
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return fmt.Sprintf("GlobalRoleBinding %q of %s %q to %s",
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d.binding.Name,
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d.binding.RoleRef.Kind,
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d.binding.RoleRef.Name,
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describeSubject(d.subject, ""),
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)
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}
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type roleBindingDescriber struct {
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binding *rbacv1.RoleBinding
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subject *rbacv1.Subject
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}
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func (d *roleBindingDescriber) String() string {
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return fmt.Sprintf("RoleBinding %q of %s %q to %s",
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d.binding.Name+"/"+d.binding.Namespace,
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d.binding.RoleRef.Kind,
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d.binding.RoleRef.Name,
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describeSubject(d.subject, d.binding.Namespace),
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)
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}
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func describeSubject(s *rbacv1.Subject, bindingNamespace string) string {
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switch s.Kind {
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case rbacv1.ServiceAccountKind:
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if len(s.Namespace) > 0 {
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return fmt.Sprintf("%s %q", s.Kind, s.Name+"/"+s.Namespace)
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}
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return fmt.Sprintf("%s %q", s.Kind, s.Name+"/"+bindingNamespace)
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default:
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return fmt.Sprintf("%s %q", s.Kind, s.Name)
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}
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}
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