certificates/authority/authority.go
Mariano Cano 38fa780775 Add interface to get root certificate from CAS.
This change makes easier the configuration of cloudCAS as it does
not require to configure the root or intermediate certificate
in the ca.json. CloudCAS will get the root certificate using
the configured certificateAuthority.
2020-09-21 15:27:20 -07:00

360 lines
10 KiB
Go

package authority
import (
"context"
"crypto/sha256"
"crypto/x509"
"encoding/hex"
"log"
"sync"
"time"
"github.com/smallstep/certificates/cas"
"github.com/pkg/errors"
"github.com/smallstep/certificates/authority/provisioner"
casapi "github.com/smallstep/certificates/cas/apiv1"
"github.com/smallstep/certificates/db"
"github.com/smallstep/certificates/kms"
kmsapi "github.com/smallstep/certificates/kms/apiv1"
"github.com/smallstep/certificates/templates"
"go.step.sm/crypto/pemutil"
"golang.org/x/crypto/ssh"
)
const (
legacyAuthority = "step-certificate-authority"
)
// Authority implements the Certificate Authority internal interface.
type Authority struct {
config *Config
keyManager kms.KeyManager
provisioners *provisioner.Collection
db db.AuthDB
templates *templates.Templates
// X509 CA
x509CAService cas.CertificateAuthorityService
rootX509Certs []*x509.Certificate
federatedX509Certs []*x509.Certificate
certificates *sync.Map
// SSH CA
sshCAUserCertSignKey ssh.Signer
sshCAHostCertSignKey ssh.Signer
sshCAUserCerts []ssh.PublicKey
sshCAHostCerts []ssh.PublicKey
sshCAUserFederatedCerts []ssh.PublicKey
sshCAHostFederatedCerts []ssh.PublicKey
// Do not re-initialize
initOnce bool
startTime time.Time
// Custom functions
sshBastionFunc func(ctx context.Context, user, hostname string) (*Bastion, error)
sshCheckHostFunc func(ctx context.Context, principal string, tok string, roots []*x509.Certificate) (bool, error)
sshGetHostsFunc func(ctx context.Context, cert *x509.Certificate) ([]Host, error)
getIdentityFunc provisioner.GetIdentityFunc
}
// New creates and initiates a new Authority type.
func New(config *Config, opts ...Option) (*Authority, error) {
err := config.Validate()
if err != nil {
return nil, err
}
var a = &Authority{
config: config,
certificates: new(sync.Map),
}
// Apply options.
for _, fn := range opts {
if err := fn(a); err != nil {
return nil, err
}
}
// Initialize authority from options or configuration.
if err := a.init(); err != nil {
return nil, err
}
return a, nil
}
// NewEmbedded initializes an authority that can be embedded in a different
// project without the limitations of the config.
func NewEmbedded(opts ...Option) (*Authority, error) {
a := &Authority{
config: &Config{},
certificates: new(sync.Map),
}
// Apply options.
for _, fn := range opts {
if err := fn(a); err != nil {
return nil, err
}
}
// Validate required options
switch {
case a.config == nil:
return nil, errors.New("cannot create an authority without a configuration")
case len(a.rootX509Certs) == 0 && a.config.Root.HasEmpties():
return nil, errors.New("cannot create an authority without a root certificate")
case a.x509CAService == nil && a.config.IntermediateCert == "":
return nil, errors.New("cannot create an authority without an issuer certificate")
case a.x509CAService == nil && a.config.IntermediateKey == "":
return nil, errors.New("cannot create an authority without an issuer signer")
}
// Initialize config required fields.
a.config.init()
// Initialize authority from options or configuration.
if err := a.init(); err != nil {
return nil, err
}
return a, nil
}
// init performs validation and initializes the fields of an Authority struct.
func (a *Authority) init() error {
// Check if handler has already been validated/initialized.
if a.initOnce {
return nil
}
var err error
// Initialize step-ca Database if it's not already initialized with WithDB.
// If a.config.DB is nil then a simple, barebones in memory DB will be used.
if a.db == nil {
if a.db, err = db.New(a.config.DB); err != nil {
return err
}
}
// Initialize key manager if it has not been set in the options.
if a.keyManager == nil {
var options kmsapi.Options
if a.config.KMS != nil {
options = *a.config.KMS
}
a.keyManager, err = kms.New(context.Background(), options)
if err != nil {
return err
}
}
// Initialize the X.509 CA Service if it has not been set in the options.
if a.x509CAService == nil {
var options casapi.Options
if a.config.CAS != nil {
options = *a.config.CAS
}
// Read intermediate and create X509 signer for default CAS.
if options.Is(casapi.SoftCAS) {
options.Issuer, err = pemutil.ReadCertificate(a.config.IntermediateCert)
if err != nil {
return err
}
options.Signer, err = a.keyManager.CreateSigner(&kmsapi.CreateSignerRequest{
SigningKey: a.config.IntermediateKey,
Password: []byte(a.config.Password),
})
if err != nil {
return err
}
}
a.x509CAService, err = cas.New(context.Background(), options)
if err != nil {
return err
}
// Get root certificate from CAS.
if srv, ok := a.x509CAService.(casapi.CertificateAuthorityGetter); ok {
resp, err := srv.GetCertificateAuthority(&casapi.GetCertificateAuthorityRequest{
Name: options.Certificateauthority,
})
if err != nil {
return err
}
a.rootX509Certs = append(a.rootX509Certs, resp.RootCertificate)
}
}
// Read root certificates and store them in the certificates map.
if len(a.rootX509Certs) == 0 {
a.rootX509Certs = make([]*x509.Certificate, len(a.config.Root))
for i, path := range a.config.Root {
crt, err := pemutil.ReadCertificate(path)
if err != nil {
return err
}
a.rootX509Certs[i] = crt
}
}
for _, crt := range a.rootX509Certs {
sum := sha256.Sum256(crt.Raw)
a.certificates.Store(hex.EncodeToString(sum[:]), crt)
}
// Read federated certificates and store them in the certificates map.
if len(a.federatedX509Certs) == 0 {
a.federatedX509Certs = make([]*x509.Certificate, len(a.config.FederatedRoots))
for i, path := range a.config.FederatedRoots {
crt, err := pemutil.ReadCertificate(path)
if err != nil {
return err
}
a.federatedX509Certs[i] = crt
}
}
for _, crt := range a.federatedX509Certs {
sum := sha256.Sum256(crt.Raw)
a.certificates.Store(hex.EncodeToString(sum[:]), crt)
}
// Decrypt and load SSH keys
var tmplVars templates.Step
if a.config.SSH != nil {
if a.config.SSH.HostKey != "" {
signer, err := a.keyManager.CreateSigner(&kmsapi.CreateSignerRequest{
SigningKey: a.config.SSH.HostKey,
Password: []byte(a.config.Password),
})
if err != nil {
return err
}
a.sshCAHostCertSignKey, err = ssh.NewSignerFromSigner(signer)
if err != nil {
return errors.Wrap(err, "error creating ssh signer")
}
// Append public key to list of host certs
a.sshCAHostCerts = append(a.sshCAHostCerts, a.sshCAHostCertSignKey.PublicKey())
a.sshCAHostFederatedCerts = append(a.sshCAHostFederatedCerts, a.sshCAHostCertSignKey.PublicKey())
}
if a.config.SSH.UserKey != "" {
signer, err := a.keyManager.CreateSigner(&kmsapi.CreateSignerRequest{
SigningKey: a.config.SSH.UserKey,
Password: []byte(a.config.Password),
})
if err != nil {
return err
}
a.sshCAUserCertSignKey, err = ssh.NewSignerFromSigner(signer)
if err != nil {
return errors.Wrap(err, "error creating ssh signer")
}
// Append public key to list of user certs
a.sshCAUserCerts = append(a.sshCAUserCerts, a.sshCAUserCertSignKey.PublicKey())
a.sshCAUserFederatedCerts = append(a.sshCAUserFederatedCerts, a.sshCAUserCertSignKey.PublicKey())
}
// Append other public keys
for _, key := range a.config.SSH.Keys {
switch key.Type {
case provisioner.SSHHostCert:
if key.Federated {
a.sshCAHostFederatedCerts = append(a.sshCAHostFederatedCerts, key.PublicKey())
} else {
a.sshCAHostCerts = append(a.sshCAHostCerts, key.PublicKey())
}
case provisioner.SSHUserCert:
if key.Federated {
a.sshCAUserFederatedCerts = append(a.sshCAUserFederatedCerts, key.PublicKey())
} else {
a.sshCAUserCerts = append(a.sshCAUserCerts, key.PublicKey())
}
default:
return errors.Errorf("unsupported type %s", key.Type)
}
}
// Configure template variables.
tmplVars.SSH.HostKey = a.sshCAHostCertSignKey.PublicKey()
tmplVars.SSH.UserKey = a.sshCAUserCertSignKey.PublicKey()
// On the templates we skip the first one because there's a distinction
// between the main key and federated keys.
tmplVars.SSH.HostFederatedKeys = append(tmplVars.SSH.HostFederatedKeys, a.sshCAHostFederatedCerts[1:]...)
tmplVars.SSH.UserFederatedKeys = append(tmplVars.SSH.UserFederatedKeys, a.sshCAUserFederatedCerts[1:]...)
}
// Merge global and configuration claims
claimer, err := provisioner.NewClaimer(a.config.AuthorityConfig.Claims, globalProvisionerClaims)
if err != nil {
return err
}
// TODO: should we also be combining the ssh federated roots here?
// If we rotate ssh roots keys, sshpop provisioner will lose ability to
// validate old SSH certificates, unless they are added as federated certs.
sshKeys, err := a.GetSSHRoots(context.Background())
if err != nil {
return err
}
// Initialize provisioners
audiences := a.config.getAudiences()
a.provisioners = provisioner.NewCollection(audiences)
config := provisioner.Config{
Claims: claimer.Claims(),
Audiences: audiences,
DB: a.db,
SSHKeys: &provisioner.SSHKeys{
UserKeys: sshKeys.UserKeys,
HostKeys: sshKeys.HostKeys,
},
GetIdentityFunc: a.getIdentityFunc,
}
// Store all the provisioners
for _, p := range a.config.AuthorityConfig.Provisioners {
if err := p.Init(config); err != nil {
return err
}
if err := a.provisioners.Store(p); err != nil {
return err
}
}
// Configure templates, currently only ssh templates are supported.
if a.sshCAHostCertSignKey != nil || a.sshCAUserCertSignKey != nil {
a.templates = a.config.Templates
if a.templates == nil {
a.templates = templates.DefaultTemplates()
}
if a.templates.Data == nil {
a.templates.Data = make(map[string]interface{})
}
a.templates.Data["Step"] = tmplVars
}
// JWT numeric dates are seconds.
a.startTime = time.Now().Truncate(time.Second)
// Set flag indicating that initialization has been completed, and should
// not be repeated.
a.initOnce = true
return nil
}
// GetDatabase returns the authority database. If the configuration does not
// define a database, GetDatabase will return a db.SimpleDB instance.
func (a *Authority) GetDatabase() db.AuthDB {
return a.db
}
// Shutdown safely shuts down any clients, databases, etc. held by the Authority.
func (a *Authority) Shutdown() error {
if err := a.keyManager.Close(); err != nil {
log.Printf("error closing the key manager: %v", err)
}
return a.db.Shutdown()
}