Files
argo-cd/util/clusterauth/clusterauth.go
2024-06-11 15:41:55 +00:00

470 lines
17 KiB
Go

package clusterauth
import (
"context"
"encoding/json"
"fmt"
"strings"
"time"
jwt "github.com/golang-jwt/jwt/v4"
log "github.com/sirupsen/logrus"
corev1 "k8s.io/api/core/v1"
rbacv1 "k8s.io/api/rbac/v1"
apierr "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/types"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/client-go/kubernetes"
"github.com/argoproj/argo-cd/v2/common"
)
// ArgoCDManagerServiceAccount is the name of the service account for managing a cluster
const (
ArgoCDManagerServiceAccount = "argocd-manager"
ArgoCDManagerClusterRole = "argocd-manager-role"
ArgoCDManagerClusterRoleBinding = "argocd-manager-role-binding"
)
// ArgoCDManagerPolicyRules are the policies to give argocd-manager
var ArgoCDManagerClusterPolicyRules = []rbacv1.PolicyRule{
{
APIGroups: []string{"*"},
Resources: []string{"*"},
Verbs: []string{"*"},
},
{
NonResourceURLs: []string{"*"},
Verbs: []string{"*"},
},
}
// ArgoCDManagerNamespacePolicyRules are the namespace level policies to give argocd-manager
var ArgoCDManagerNamespacePolicyRules = []rbacv1.PolicyRule{
{
APIGroups: []string{"*"},
Resources: []string{"*"},
Verbs: []string{"*"},
},
}
// CreateServiceAccount creates a service account in a given namespace
func CreateServiceAccount(
clientset kubernetes.Interface,
serviceAccountName string,
namespace string,
) error {
serviceAccount := corev1.ServiceAccount{
TypeMeta: metav1.TypeMeta{
APIVersion: "v1",
Kind: "ServiceAccount",
},
ObjectMeta: metav1.ObjectMeta{
Name: serviceAccountName,
Namespace: namespace,
},
}
_, err := clientset.CoreV1().ServiceAccounts(namespace).Create(context.Background(), &serviceAccount, metav1.CreateOptions{})
if err != nil {
if !apierr.IsAlreadyExists(err) {
return fmt.Errorf("Failed to create service account %q in namespace %q: %w", serviceAccountName, namespace, err)
}
log.Infof("ServiceAccount %q already exists in namespace %q", serviceAccountName, namespace)
return nil
}
log.Infof("ServiceAccount %q created in namespace %q", serviceAccountName, namespace)
return nil
}
func upsert(kind string, name string, create func() (interface{}, error), update func() (interface{}, error)) error {
_, err := create()
if err != nil {
if !apierr.IsAlreadyExists(err) {
return fmt.Errorf("Failed to create %s %q: %w", kind, name, err)
}
_, err = update()
if err != nil {
return fmt.Errorf("Failed to update %s %q: %w", kind, name, err)
}
log.Infof("%s %q updated", kind, name)
} else {
log.Infof("%s %q created", kind, name)
}
return nil
}
func upsertClusterRole(clientset kubernetes.Interface, name string, rules []rbacv1.PolicyRule) error {
clusterRole := rbacv1.ClusterRole{
TypeMeta: metav1.TypeMeta{
APIVersion: "rbac.authorization.k8s.io/v1",
Kind: "ClusterRole",
},
ObjectMeta: metav1.ObjectMeta{
Name: name,
},
Rules: rules,
}
return upsert("ClusterRole", name, func() (interface{}, error) {
return clientset.RbacV1().ClusterRoles().Create(context.Background(), &clusterRole, metav1.CreateOptions{})
}, func() (interface{}, error) {
return clientset.RbacV1().ClusterRoles().Update(context.Background(), &clusterRole, metav1.UpdateOptions{})
})
}
func upsertRole(clientset kubernetes.Interface, name string, namespace string, rules []rbacv1.PolicyRule) error {
role := rbacv1.Role{
TypeMeta: metav1.TypeMeta{
APIVersion: "rbac.authorization.k8s.io/v1",
Kind: "Role",
},
ObjectMeta: metav1.ObjectMeta{
Name: name,
},
Rules: rules,
}
return upsert("Role", fmt.Sprintf("%s/%s", namespace, name), func() (interface{}, error) {
return clientset.RbacV1().Roles(namespace).Create(context.Background(), &role, metav1.CreateOptions{})
}, func() (interface{}, error) {
return clientset.RbacV1().Roles(namespace).Update(context.Background(), &role, metav1.UpdateOptions{})
})
}
func upsertClusterRoleBinding(clientset kubernetes.Interface, name string, clusterRoleName string, subject rbacv1.Subject) error {
roleBinding := rbacv1.ClusterRoleBinding{
TypeMeta: metav1.TypeMeta{
APIVersion: "rbac.authorization.k8s.io/v1",
Kind: "ClusterRoleBinding",
},
ObjectMeta: metav1.ObjectMeta{
Name: name,
},
RoleRef: rbacv1.RoleRef{
APIGroup: "rbac.authorization.k8s.io",
Kind: "ClusterRole",
Name: clusterRoleName,
},
Subjects: []rbacv1.Subject{subject},
}
return upsert("ClusterRoleBinding", name, func() (interface{}, error) {
return clientset.RbacV1().ClusterRoleBindings().Create(context.Background(), &roleBinding, metav1.CreateOptions{})
}, func() (interface{}, error) {
return clientset.RbacV1().ClusterRoleBindings().Update(context.Background(), &roleBinding, metav1.UpdateOptions{})
})
}
func upsertRoleBinding(clientset kubernetes.Interface, name string, roleName string, namespace string, subject rbacv1.Subject) error {
roleBinding := rbacv1.RoleBinding{
TypeMeta: metav1.TypeMeta{
APIVersion: "rbac.authorization.k8s.io/v1",
Kind: "RoleBinding",
},
ObjectMeta: metav1.ObjectMeta{
Name: name,
},
RoleRef: rbacv1.RoleRef{
APIGroup: "rbac.authorization.k8s.io",
Kind: "Role",
Name: roleName,
},
Subjects: []rbacv1.Subject{subject},
}
return upsert("RoleBinding", fmt.Sprintf("%s/%s", namespace, name), func() (interface{}, error) {
return clientset.RbacV1().RoleBindings(namespace).Create(context.Background(), &roleBinding, metav1.CreateOptions{})
}, func() (interface{}, error) {
return clientset.RbacV1().RoleBindings(namespace).Update(context.Background(), &roleBinding, metav1.UpdateOptions{})
})
}
// InstallClusterManagerRBAC installs RBAC resources for a cluster manager to operate a cluster. Returns a token
func InstallClusterManagerRBAC(clientset kubernetes.Interface, ns string, namespaces []string, bearerTokenTimeout time.Duration) (string, error) {
err := CreateServiceAccount(clientset, ArgoCDManagerServiceAccount, ns)
if err != nil {
return "", err
}
if len(namespaces) == 0 {
err = upsertClusterRole(clientset, ArgoCDManagerClusterRole, ArgoCDManagerClusterPolicyRules)
if err != nil {
return "", err
}
err = upsertClusterRoleBinding(clientset, ArgoCDManagerClusterRoleBinding, ArgoCDManagerClusterRole, rbacv1.Subject{
Kind: rbacv1.ServiceAccountKind,
Name: ArgoCDManagerServiceAccount,
Namespace: ns,
})
if err != nil {
return "", err
}
} else {
for _, namespace := range namespaces {
err = upsertRole(clientset, ArgoCDManagerClusterRole, namespace, ArgoCDManagerNamespacePolicyRules)
if err != nil {
return "", err
}
err = upsertRoleBinding(clientset, ArgoCDManagerClusterRoleBinding, ArgoCDManagerClusterRole, namespace, rbacv1.Subject{
Kind: rbacv1.ServiceAccountKind,
Name: ArgoCDManagerServiceAccount,
Namespace: ns,
})
if err != nil {
return "", err
}
}
}
return GetServiceAccountBearerToken(clientset, ns, ArgoCDManagerServiceAccount, bearerTokenTimeout)
}
// GetServiceAccountBearerToken determines if a ServiceAccount has a
// bearer token secret to use or if a secret should be created. It then
// waits for the secret to have a bearer token if a secret needs to
// be created and returns the token in encoded base64.
func GetServiceAccountBearerToken(clientset kubernetes.Interface, ns string, sa string, timeout time.Duration) (string, error) {
secretName, err := getOrCreateServiceAccountTokenSecret(clientset, sa, ns)
if err != nil {
return "", err
}
var secret *corev1.Secret
err = wait.PollUntilContextTimeout(context.Background(), 500*time.Millisecond, timeout, true, func(ctx context.Context) (bool, error) {
ctx, cancel := context.WithTimeout(ctx, common.ClusterAuthRequestTimeout)
defer cancel()
secret, err = clientset.CoreV1().Secrets(ns).Get(ctx, secretName, metav1.GetOptions{})
if err != nil {
return false, fmt.Errorf("failed to get secret %q for serviceaccount %q: %w", secretName, sa, err)
}
_, ok := secret.Data["token"]
if !ok {
return false, nil
}
return true, nil
})
if err != nil {
return "", fmt.Errorf("failed to get token for serviceaccount %q: %w", sa, err)
}
return string(secret.Data["token"]), nil
}
// getOrCreateServiceAccountTokenSecret will check if a ServiceAccount
// already has a kubernetes.io/service-account-token secret associated
// with it or creates one if the ServiceAccount doesn't have one. This
// was added to help add k8s v1.24+ clusters.
func getOrCreateServiceAccountTokenSecret(clientset kubernetes.Interface, sa, ns string) (string, error) {
// Wait for sa to have secret, but don't wait too
// long for 1.24+ clusters
var serviceAccount *corev1.ServiceAccount
err := wait.PollUntilContextTimeout(context.Background(), 500*time.Millisecond, 30*time.Second, true, func(ctx context.Context) (bool, error) {
ctx, cancel := context.WithTimeout(ctx, common.ClusterAuthRequestTimeout)
defer cancel()
var getErr error
serviceAccount, getErr = clientset.CoreV1().ServiceAccounts(ns).Get(ctx, sa, metav1.GetOptions{})
if getErr != nil {
return false, fmt.Errorf("failed to get serviceaccount %q: %w", sa, getErr)
}
return true, nil
})
if err != nil && !wait.Interrupted(err) {
return "", fmt.Errorf("failed to get serviceaccount token secret: %w", err)
}
if serviceAccount == nil {
log.Errorf("Unexpected nil serviceaccount '%s/%s' with no error returned", ns, sa)
return "", fmt.Errorf("failed to create serviceaccount token secret: nil serviceaccount returned for '%s/%s' with no error", ns, sa)
}
outerCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
for _, s := range serviceAccount.Secrets {
innerCtx, cancel := context.WithTimeout(outerCtx, common.ClusterAuthRequestTimeout)
defer cancel()
existingSecret, err := clientset.CoreV1().Secrets(ns).Get(innerCtx, s.Name, metav1.GetOptions{})
if err != nil {
return "", fmt.Errorf("failed to retrieve secret %q: %w", s.Name, err)
}
if existingSecret.Type == corev1.SecretTypeServiceAccountToken {
return existingSecret.Name, nil
}
}
return createServiceAccountToken(clientset, serviceAccount)
}
func createServiceAccountToken(clientset kubernetes.Interface, serviceAccount *corev1.ServiceAccount) (string, error) {
secret := &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
GenerateName: serviceAccount.Name + "-token-",
Namespace: serviceAccount.Namespace,
Annotations: map[string]string{
corev1.ServiceAccountNameKey: serviceAccount.Name,
},
},
Type: corev1.SecretTypeServiceAccountToken,
}
ctx, cancel := context.WithTimeout(context.Background(), common.ClusterAuthRequestTimeout)
defer cancel()
secret, err := clientset.CoreV1().Secrets(serviceAccount.Namespace).Create(ctx, secret, metav1.CreateOptions{})
if err != nil {
return "", fmt.Errorf("failed to create secret for serviceaccount %q: %w", serviceAccount.Name, err)
}
log.Infof("Created bearer token secret for ServiceAccount %q", serviceAccount.Name)
serviceAccount.Secrets = []corev1.ObjectReference{{
Name: secret.Name,
Namespace: secret.Namespace,
}}
patch, err := json.Marshal(serviceAccount)
if err != nil {
return "", fmt.Errorf("failed marshaling patch for serviceaccount %q: %w", serviceAccount.Name, err)
}
_, err = clientset.CoreV1().ServiceAccounts(serviceAccount.Namespace).Patch(ctx, serviceAccount.Name, types.StrategicMergePatchType, patch, metav1.PatchOptions{})
if err != nil {
return "", fmt.Errorf("failed to patch serviceaccount %q with bearer token secret: %w", serviceAccount.Name, err)
}
return secret.Name, nil
}
// UninstallClusterManagerRBAC removes RBAC resources for a cluster manager to operate a cluster
func UninstallClusterManagerRBAC(clientset kubernetes.Interface) error {
return UninstallRBAC(clientset, "kube-system", ArgoCDManagerClusterRoleBinding, ArgoCDManagerClusterRole, ArgoCDManagerServiceAccount)
}
// UninstallRBAC uninstalls RBAC related resources for a binding, role, and service account
func UninstallRBAC(clientset kubernetes.Interface, namespace, bindingName, roleName, serviceAccount string) error {
if err := clientset.RbacV1().ClusterRoleBindings().Delete(context.Background(), bindingName, metav1.DeleteOptions{}); err != nil {
if !apierr.IsNotFound(err) {
return fmt.Errorf("Failed to delete ClusterRoleBinding: %w", err)
}
log.Infof("ClusterRoleBinding %q not found", bindingName)
} else {
log.Infof("ClusterRoleBinding %q deleted", bindingName)
}
if err := clientset.RbacV1().ClusterRoles().Delete(context.Background(), roleName, metav1.DeleteOptions{}); err != nil {
if !apierr.IsNotFound(err) {
return fmt.Errorf("Failed to delete ClusterRole: %w", err)
}
log.Infof("ClusterRole %q not found", roleName)
} else {
log.Infof("ClusterRole %q deleted", roleName)
}
if err := clientset.CoreV1().ServiceAccounts(namespace).Delete(context.Background(), serviceAccount, metav1.DeleteOptions{}); err != nil {
if !apierr.IsNotFound(err) {
return fmt.Errorf("Failed to delete ServiceAccount: %w", err)
}
log.Infof("ServiceAccount %q in namespace %q not found", serviceAccount, namespace)
} else {
log.Infof("ServiceAccount %q deleted", serviceAccount)
}
return nil
}
type ServiceAccountClaims struct {
Sub string `json:"sub"`
Iss string `json:"iss"`
Namespace string `json:"kubernetes.io/serviceaccount/namespace"`
SecretName string `json:"kubernetes.io/serviceaccount/secret.name"`
ServiceAccountName string `json:"kubernetes.io/serviceaccount/service-account.name"`
ServiceAccountUID string `json:"kubernetes.io/serviceaccount/service-account.uid"`
}
// Valid satisfies the jwt.Claims interface to enable JWT parsing
func (sac *ServiceAccountClaims) Valid() error {
return nil
}
// ParseServiceAccountToken parses a Kubernetes service account token
func ParseServiceAccountToken(token string) (*ServiceAccountClaims, error) {
parser := jwt.NewParser(jwt.WithoutClaimsValidation())
var claims ServiceAccountClaims
_, _, err := parser.ParseUnverified(token, &claims)
if err != nil {
return nil, fmt.Errorf("Failed to parse service account token: %w", err)
}
return &claims, nil
}
// GenerateNewClusterManagerSecret creates a new secret derived with same metadata as existing one
// and waits until the secret is populated with a bearer token
func GenerateNewClusterManagerSecret(clientset kubernetes.Interface, claims *ServiceAccountClaims) (*corev1.Secret, error) {
secretsClient := clientset.CoreV1().Secrets(claims.Namespace)
existingSecret, err := secretsClient.Get(context.Background(), claims.SecretName, metav1.GetOptions{})
if err != nil {
return nil, err
}
var newSecret corev1.Secret
secretNameSplit := strings.Split(claims.SecretName, "-")
if len(secretNameSplit) > 0 {
secretNameSplit = secretNameSplit[:len(secretNameSplit)-1]
}
newSecret.Type = corev1.SecretTypeServiceAccountToken
newSecret.GenerateName = strings.Join(secretNameSplit, "-") + "-"
newSecret.Annotations = existingSecret.Annotations
// We will create an empty secret and let kubernetes populate the data
newSecret.Data = nil
created, err := secretsClient.Create(context.Background(), &newSecret, metav1.CreateOptions{})
if err != nil {
return nil, err
}
err = wait.PollUntilContextTimeout(context.Background(), 500*time.Millisecond, 30*time.Second, false, func(ctx context.Context) (bool, error) {
created, err = secretsClient.Get(ctx, created.Name, metav1.GetOptions{})
if err != nil {
return false, err
}
if len(created.Data) == 0 {
return false, nil
}
return true, nil
})
if err != nil {
return nil, fmt.Errorf("Timed out waiting for secret to generate new token: %w", err)
}
return created, nil
}
// RotateServiceAccountSecrets rotates the entries in the service accounts secrets list
func RotateServiceAccountSecrets(clientset kubernetes.Interface, claims *ServiceAccountClaims, newSecret *corev1.Secret) error {
// 1. update service account secrets list with new secret name while also removing the old name
saClient := clientset.CoreV1().ServiceAccounts(claims.Namespace)
sa, err := saClient.Get(context.Background(), claims.ServiceAccountName, metav1.GetOptions{})
if err != nil {
return err
}
var newSecretsList []corev1.ObjectReference
alreadyPresent := false
for _, objRef := range sa.Secrets {
if objRef.Name == claims.SecretName {
continue
}
if objRef.Name == newSecret.Name {
alreadyPresent = true
}
newSecretsList = append(newSecretsList, objRef)
}
if !alreadyPresent {
sa.Secrets = append(newSecretsList, corev1.ObjectReference{Name: newSecret.Name})
}
_, err = saClient.Update(context.Background(), sa, metav1.UpdateOptions{})
if err != nil {
return err
}
// 2. delete existing secret object
secretsClient := clientset.CoreV1().Secrets(claims.Namespace)
err = secretsClient.Delete(context.Background(), claims.SecretName, metav1.DeleteOptions{})
if !apierr.IsNotFound(err) {
return err
}
return nil
}