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gatekeeper.go
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gatekeeper.go
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package auth
import (
"context"
"fmt"
"net/http"
"os"
"sort"
"strconv"
"github.com/argoproj/argo-workflows/v3/util/secrets"
eventsource "github.com/argoproj/argo-events/pkg/client/eventsource/clientset/versioned"
sensor "github.com/argoproj/argo-events/pkg/client/sensor/clientset/versioned"
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"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/client-go/dynamic"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
workflow "github.com/argoproj/argo-workflows/v3/pkg/client/clientset/versioned"
"github.com/argoproj/argo-workflows/v3/server/auth/serviceaccount"
"github.com/argoproj/argo-workflows/v3/server/auth/sso"
"github.com/argoproj/argo-workflows/v3/server/auth/types"
"github.com/argoproj/argo-workflows/v3/server/cache"
servertypes "github.com/argoproj/argo-workflows/v3/server/types"
"github.com/argoproj/argo-workflows/v3/util/expr/argoexpr"
jsonutil "github.com/argoproj/argo-workflows/v3/util/json"
"github.com/argoproj/argo-workflows/v3/util/kubeconfig"
"github.com/argoproj/argo-workflows/v3/workflow/common"
)
type ContextKey string
const (
DynamicKey ContextKey = "dynamic.Interface"
WfKey ContextKey = "workflow.Interface"
SensorKey ContextKey = "sensor.Interface"
EventSourceKey ContextKey = "eventsource.Interface"
KubeKey ContextKey = "kubernetes.Interface"
ClaimsKey ContextKey = "types.Claims"
)
//go:generate mockery --name=Gatekeeper
type Gatekeeper interface {
ContextWithRequest(ctx context.Context, req interface{}) (context.Context, error)
Context(ctx context.Context) (context.Context, error)
UnaryServerInterceptor() grpc.UnaryServerInterceptor
StreamServerInterceptor() grpc.StreamServerInterceptor
}
type ClientForAuthorization func(authorization string) (*rest.Config, *servertypes.Clients, error)
type gatekeeper struct {
Modes Modes
// global clients, not to be used if there are better ones
clients *servertypes.Clients
restConfig *rest.Config
ssoIf sso.Interface
clientForAuthorization ClientForAuthorization
// The namespace the server is installed in.
namespace string
ssoNamespace string
namespaced bool
cache *cache.ResourceCache
}
func NewGatekeeper(modes Modes, clients *servertypes.Clients, restConfig *rest.Config, ssoIf sso.Interface, clientForAuthorization ClientForAuthorization, namespace string, ssoNamespace string, namespaced bool, cache *cache.ResourceCache) (Gatekeeper, error) {
if len(modes) == 0 {
return nil, fmt.Errorf("must specify at least one auth mode")
}
return &gatekeeper{
modes,
clients,
restConfig,
ssoIf,
clientForAuthorization,
namespace,
ssoNamespace,
namespaced,
cache,
}, 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.ContextWithRequest(ctx, req)
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 {
return handler(srv, NewAuthorizingServerStream(ss, s))
}
}
func (s *gatekeeper) ContextWithRequest(ctx context.Context, req interface{}) (context.Context, error) {
clients, claims, err := s.getClients(ctx, req)
if err != nil {
return nil, err
}
ctx = context.WithValue(ctx, DynamicKey, clients.Dynamic)
ctx = context.WithValue(ctx, WfKey, clients.Workflow)
ctx = context.WithValue(ctx, EventSourceKey, clients.EventSource)
ctx = context.WithValue(ctx, SensorKey, clients.Sensor)
ctx = context.WithValue(ctx, KubeKey, clients.Kubernetes)
ctx = context.WithValue(ctx, ClaimsKey, claims)
return ctx, nil
}
func (s *gatekeeper) Context(ctx context.Context) (context.Context, error) {
return s.ContextWithRequest(ctx, nil)
}
func GetDynamicClient(ctx context.Context) dynamic.Interface {
return ctx.Value(DynamicKey).(dynamic.Interface)
}
func GetWfClient(ctx context.Context) workflow.Interface {
return ctx.Value(WfKey).(workflow.Interface)
}
func GetEventSourceClient(ctx context.Context) eventsource.Interface {
return ctx.Value(EventSourceKey).(eventsource.Interface)
}
func GetSensorClient(ctx context.Context) sensor.Interface {
return ctx.Value(SensorKey).(sensor.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 getAuthHeaders(md metadata.MD) []string {
// looks for the HTTP header `Authorization: Bearer ...`
for _, t := range md.Get("authorization") {
return []string{t}
}
// check the HTTP cookie
// In cases such as wildcard domain cookies, there could be multiple authorization headers
var authorizations []string
for _, t := range md.Get("cookie") {
header := http.Header{}
header.Add("Cookie", t)
request := http.Request{Header: header}
cookies := request.Cookies()
for _, c := range cookies {
if c.Name == "authorization" {
authorizations = append(authorizations, c.Value)
}
}
}
return authorizations
}
func (s gatekeeper) getClients(ctx context.Context, req interface{}) (*servertypes.Clients, *types.Claims, error) {
md, _ := metadata.FromIncomingContext(ctx)
authorizations := getAuthHeaders(md)
// Required for GetMode() with Server auth when no auth header specified
if len(authorizations) == 0 {
authorizations = append(authorizations, "")
}
valid := false
var mode Mode
var authorization string
for _, token := range authorizations {
mode, valid = s.Modes.GetMode(token)
// Stop checking after the first valid token
if valid {
authorization = token
break
}
}
if !valid {
return nil, nil, status.Error(codes.Unauthenticated, "token not valid for running mode")
}
switch mode {
case Client:
restConfig, clients, err := s.clientForAuthorization(authorization)
if err != nil {
return nil, nil, status.Error(codes.Unauthenticated, err.Error())
}
claims, _ := serviceaccount.ClaimSetFor(restConfig)
return clients, claims, nil
case Server:
claims, _ := serviceaccount.ClaimSetFor(s.restConfig)
return s.clients, claims, nil
case SSO:
claims, err := s.ssoIf.Authorize(authorization)
if err != nil {
return nil, nil, status.Error(codes.Unauthenticated, err.Error())
}
if s.ssoIf.IsRBACEnabled() {
clients, err := s.rbacAuthorization(ctx, claims, req)
if err != nil {
log.WithError(err).Error("failed to perform RBAC authorization")
return nil, nil, status.Error(codes.PermissionDenied, "not allowed")
}
return clients, claims, nil
} else {
// important! write an audit entry (i.e. log entry) so we know which user performed an operation
log.WithFields(addClaimsLogFields(claims, nil)).Info("using the default service account for user")
return s.clients, claims, nil
}
default:
panic("this should never happen")
}
}
func getNamespace(req interface{}) string {
if req == nil {
return ""
}
namespacedRequest, ok := req.(servertypes.NamespacedRequest)
if !ok {
return ""
}
return namespacedRequest.GetNamespace()
}
func precedence(serviceAccount *corev1.ServiceAccount) int {
i, _ := strconv.Atoi(serviceAccount.Annotations[common.AnnotationKeyRBACRulePrecedence])
return i
}
func (s *gatekeeper) getServiceAccount(claims *types.Claims, namespace string) (*corev1.ServiceAccount, error) {
list, err := s.cache.ServiceAccountLister.ServiceAccounts(namespace).List(labels.Everything())
if err != nil {
return nil, fmt.Errorf("failed to list SSO RBAC service accounts: %w", err)
}
var serviceAccounts []*corev1.ServiceAccount
for _, serviceAccount := range list {
_, ok := serviceAccount.Annotations[common.AnnotationKeyRBACRule]
if !ok {
continue
}
serviceAccounts = append(serviceAccounts, serviceAccount)
}
sort.Slice(serviceAccounts, func(i, j int) bool { return precedence(serviceAccounts[i]) > precedence(serviceAccounts[j]) })
for _, serviceAccount := range serviceAccounts {
rule := serviceAccount.Annotations[common.AnnotationKeyRBACRule]
v, err := jsonutil.Jsonify(claims)
if err != nil {
return nil, fmt.Errorf("failed to marshall claims: %w", err)
}
allow, err := argoexpr.EvalBool(rule, v)
if err != nil {
return nil, fmt.Errorf("failed to evaluate rule: %w", err)
}
if !allow {
continue
}
return serviceAccount, nil
}
return nil, fmt.Errorf("no service account rule matches")
}
func (s *gatekeeper) canDelegateRBACToRequestNamespace(req interface{}) bool {
if s.namespaced || os.Getenv("SSO_DELEGATE_RBAC_TO_NAMESPACE") != "true" {
return false
}
namespace := getNamespace(req)
return len(namespace) != 0 && s.ssoNamespace != namespace
}
func (s *gatekeeper) getClientsForServiceAccount(ctx context.Context, claims *types.Claims, serviceAccount *corev1.ServiceAccount) (*servertypes.Clients, error) {
authorization, err := s.authorizationForServiceAccount(ctx, serviceAccount)
if err != nil {
return nil, err
}
_, clients, err := s.clientForAuthorization(authorization)
if err != nil {
return nil, err
}
claims.ServiceAccountName = serviceAccount.Name
claims.ServiceAccountNamespace = serviceAccount.Namespace
return clients, nil
}
func (s *gatekeeper) rbacAuthorization(ctx context.Context, claims *types.Claims, req interface{}) (*servertypes.Clients, error) {
ssoDelegationAllowed, ssoDelegated := false, false
loginAccount, err := s.getServiceAccount(claims, s.ssoNamespace)
if err != nil {
return nil, err
}
delegatedAccount := loginAccount
if s.canDelegateRBACToRequestNamespace(req) {
ssoDelegationAllowed = true
namespaceAccount, err := s.getServiceAccount(claims, getNamespace(req))
if err != nil {
log.WithError(err).Info("Error while SSO Delegation")
} else if precedence(namespaceAccount) > precedence(loginAccount) {
delegatedAccount = namespaceAccount
ssoDelegated = true
}
}
// important! write an audit entry (i.e. log entry) so we know which user performed an operation
log.WithFields(log.Fields{"serviceAccount": delegatedAccount.Name, "loginServiceAccount": loginAccount.Name, "subject": claims.Subject, "email": claims.Email, "ssoDelegationAllowed": ssoDelegationAllowed, "ssoDelegated": ssoDelegated}).Info("selected SSO RBAC service account for user")
return s.getClientsForServiceAccount(ctx, claims, delegatedAccount)
}
func (s *gatekeeper) authorizationForServiceAccount(ctx context.Context, serviceAccount *corev1.ServiceAccount) (string, error) {
secretName := secrets.TokenNameForServiceAccount(serviceAccount)
secret, err := s.cache.GetSecret(ctx, serviceAccount.GetNamespace(), secretName)
if err != nil {
return "", fmt.Errorf("failed to get service account secret: %w", err)
}
return "Bearer " + string(secret.Data["token"]), nil
}
func addClaimsLogFields(claims *types.Claims, fields log.Fields) log.Fields {
if fields == nil {
fields = log.Fields{}
}
fields["subject"] = claims.Subject
if claims.Email != "" {
fields["email"] = claims.Email
}
return fields
}
func DefaultClientForAuthorization(authorization string) (*rest.Config, *servertypes.Clients, error) {
restConfig, err := kubeconfig.GetRestConfig(authorization)
if err != nil {
return nil, nil, fmt.Errorf("failed to create REST config: %w", err)
}
dynamicClient, err := dynamic.NewForConfig(restConfig)
if err != nil {
return nil, nil, fmt.Errorf("failure to create dynamic client: %w", err)
}
wfClient, err := workflow.NewForConfig(restConfig)
if err != nil {
return nil, nil, fmt.Errorf("failure to create workflow client: %w", err)
}
eventSourceClient, err := eventsource.NewForConfig(restConfig)
if err != nil {
return nil, nil, fmt.Errorf("failure to create event source client: %w", err)
}
sensorClient, err := sensor.NewForConfig(restConfig)
if err != nil {
return nil, nil, fmt.Errorf("failure to create sensor client: %w", err)
}
kubeClient, err := kubernetes.NewForConfig(restConfig)
if err != nil {
return nil, nil, fmt.Errorf("failure to create kubernetes client: %w", err)
}
return restConfig, &servertypes.Clients{
Dynamic: dynamicClient,
Workflow: wfClient,
Sensor: sensorClient,
EventSource: eventSourceClient,
Kubernetes: kubeClient,
}, nil
}