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gatekeeper.go
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gatekeeper.go
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package auth
import (
"context"
"encoding/json"
"fmt"
"net/http"
"sort"
"strconv"
"github.com/antonmedv/expr"
grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
log "github.com/sirupsen/logrus"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/status"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
"github.com/argoproj/argo/v2/pkg/client/clientset/versioned"
"github.com/argoproj/argo/v2/server/auth/serviceaccount"
"github.com/argoproj/argo/v2/server/auth/sso"
"github.com/argoproj/argo/v2/server/auth/types"
"github.com/argoproj/argo/v2/util/kubeconfig"
"github.com/argoproj/argo/v2/workflow/common"
)
type ContextKey string
const (
WfKey ContextKey = "versioned.Interface"
KubeKey ContextKey = "kubernetes.Interface"
ClaimsKey ContextKey = "types.Claims"
)
//go:generate mockery -name Gatekeeper
type Gatekeeper interface {
Context(ctx context.Context) (context.Context, error)
UnaryServerInterceptor() grpc.UnaryServerInterceptor
StreamServerInterceptor() grpc.StreamServerInterceptor
}
type ClientForAuthorization func(authorization string) (*rest.Config, versioned.Interface, kubernetes.Interface, error)
type gatekeeper struct {
Modes Modes
// global clients, not to be used if there are better ones
wfClient versioned.Interface
kubeClient kubernetes.Interface
restConfig *rest.Config
ssoIf sso.Interface
clientForAuthorization ClientForAuthorization
// The namespace the server is installed in.
namespace string
}
func NewGatekeeper(modes Modes, wfClient versioned.Interface, kubeClient kubernetes.Interface, restConfig *rest.Config, ssoIf sso.Interface, clientForAuthorization ClientForAuthorization, namespace string) (Gatekeeper, error) {
if len(modes) == 0 {
return nil, fmt.Errorf("must specify at least one auth mode")
}
return &gatekeeper{modes, wfClient, kubeClient, restConfig, ssoIf, clientForAuthorization, namespace}, nil
}
func (s *gatekeeper) UnaryServerInterceptor() grpc.UnaryServerInterceptor {
return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
ctx, err = s.Context(ctx)
if err != nil {
return nil, err
}
return handler(ctx, req)
}
}
func (s *gatekeeper) StreamServerInterceptor() grpc.StreamServerInterceptor {
return func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
ctx, err := s.Context(ss.Context())
if err != nil {
return err
}
wrapped := grpc_middleware.WrapServerStream(ss)
wrapped.WrappedContext = ctx
return handler(srv, wrapped)
}
}
func (s *gatekeeper) Context(ctx context.Context) (context.Context, error) {
wfClient, kubeClient, claims, err := s.getClients(ctx)
if err != nil {
return nil, err
}
return context.WithValue(context.WithValue(context.WithValue(ctx, WfKey, wfClient), KubeKey, kubeClient), ClaimsKey, claims), nil
}
func GetWfClient(ctx context.Context) versioned.Interface {
return ctx.Value(WfKey).(versioned.Interface)
}
func GetKubeClient(ctx context.Context) kubernetes.Interface {
return ctx.Value(KubeKey).(kubernetes.Interface)
}
func GetClaims(ctx context.Context) *types.Claims {
config, _ := ctx.Value(ClaimsKey).(*types.Claims)
return config
}
func getAuthHeader(md metadata.MD) string {
// looks for the HTTP header `Authorization: Bearer ...`
for _, t := range md.Get("authorization") {
return t
}
// check the HTTP cookie
for _, t := range md.Get("cookie") {
header := http.Header{}
header.Add("Cookie", t)
request := http.Request{Header: header}
token, err := request.Cookie("authorization")
if err == nil {
return token.Value
}
}
return ""
}
func (s gatekeeper) getClients(ctx context.Context) (versioned.Interface, kubernetes.Interface, *types.Claims, error) {
md, _ := metadata.FromIncomingContext(ctx)
authorization := getAuthHeader(md)
mode, valid := s.Modes.GetMode(authorization)
if !valid {
return nil, nil, nil, status.Error(codes.Unauthenticated, "token not valid for running mode")
}
switch mode {
case Client:
restConfig, wfClient, kubeClient, err := s.clientForAuthorization(authorization)
if err != nil {
return nil, nil, nil, status.Error(codes.Unauthenticated, err.Error())
}
claims, _ := serviceaccount.ClaimSetFor(restConfig)
return wfClient, kubeClient, claims, nil
case Server:
claims, _ := serviceaccount.ClaimSetFor(s.restConfig)
return s.wfClient, s.kubeClient, claims, nil
case SSO:
claims, err := s.ssoIf.Authorize(authorization)
if err != nil {
return nil, nil, nil, status.Error(codes.Unauthenticated, err.Error())
}
if s.ssoIf.IsRBACEnabled() {
v, k, err := s.rbacAuthorization(claims)
if err != nil {
log.WithError(err).Error("failed to perform RBAC authorization")
return nil, nil, nil, status.Error(codes.PermissionDenied, "not allowed")
}
return v, k, claims, nil
} else {
return s.wfClient, s.kubeClient, claims, nil
}
default:
panic("this should never happen")
}
}
func (s *gatekeeper) rbacAuthorization(claims *types.Claims) (versioned.Interface, kubernetes.Interface, error) {
list, err := s.kubeClient.CoreV1().ServiceAccounts(s.namespace).List(metav1.ListOptions{})
if err != nil {
return nil, nil, fmt.Errorf("failed to list SSO RBAC service accounts: %w", err)
}
var serviceAccounts []corev1.ServiceAccount
for _, serviceAccount := range list.Items {
_, ok := serviceAccount.Annotations[common.AnnotationKeyRBACRule]
if !ok {
continue
}
serviceAccounts = append(serviceAccounts, serviceAccount)
}
precedence := func(serviceAccount corev1.ServiceAccount) int {
i, _ := strconv.Atoi(serviceAccount.Annotations[common.AnnotationKeyRBACRulePrecedence])
return i
}
sort.Slice(serviceAccounts, func(i, j int) bool { return precedence(serviceAccounts[i]) > precedence(serviceAccounts[j]) })
for _, serviceAccount := range serviceAccounts {
rule := serviceAccount.Annotations[common.AnnotationKeyRBACRule]
data, err := json.Marshal(claims)
if err != nil {
return nil, nil, fmt.Errorf("failed to marshall claims: %w", err)
}
v := make(map[string]interface{})
err = json.Unmarshal(data, &v)
if err != nil {
return nil, nil, fmt.Errorf("failed to unmarshall claims: %w", err)
}
result, err := expr.Eval(rule, v)
if err != nil {
return nil, nil, fmt.Errorf("failed to evaluate rule: %w", err)
}
allow, ok := result.(bool)
if !ok {
return nil, nil, fmt.Errorf("failed to evaluate rule: not a boolean")
}
if !allow {
continue
}
authorization, err := s.authorizationForServiceAccount(serviceAccount.Name)
if err != nil {
return nil, nil, err
}
_, wfClient, kubeClient, err := s.clientForAuthorization(authorization)
if err != nil {
return nil, nil, err
}
log.WithFields(log.Fields{"serviceAccount": serviceAccount.Name, "subject": claims.Subject}).Info("selected SSO RBAC service account for user")
return wfClient, kubeClient, nil
}
return nil, nil, fmt.Errorf("no service account rule matches")
}
func (s *gatekeeper) authorizationForServiceAccount(serviceAccountName string) (string, error) {
serviceAccount, err := s.kubeClient.CoreV1().ServiceAccounts(s.namespace).Get(serviceAccountName, metav1.GetOptions{})
if err != nil {
return "", fmt.Errorf("failed to get service account: %w", err)
}
if len(serviceAccount.Secrets) == 0 {
return "", fmt.Errorf("expected at least one secret for SSO RBAC service account: %w", err)
}
secret, err := s.kubeClient.CoreV1().Secrets(s.namespace).Get(serviceAccount.Secrets[0].Name, metav1.GetOptions{})
if err != nil {
return "", fmt.Errorf("failed to get service account secret: %w", err)
}
return "Bearer " + string(secret.Data["token"]), nil
}
func DefaultClientForAuthorization(authorization string) (*rest.Config, versioned.Interface, kubernetes.Interface, error) {
restConfig, err := kubeconfig.GetRestConfig(authorization)
if err != nil {
return nil, nil, nil, fmt.Errorf("failed to create REST config: %w", err)
}
wfClient, err := versioned.NewForConfig(restConfig)
if err != nil {
return nil, nil, nil, fmt.Errorf("failure to create workflow client: %w", err)
}
kubeClient, err := kubernetes.NewForConfig(restConfig)
if err != nil {
return nil, nil, nil, fmt.Errorf("failure to create kubernetes client: %w", err)
}
return restConfig, wfClient, kubeClient, nil
}