303 lines
13 KiB
Go
303 lines
13 KiB
Go
package controlapi
|
|
|
|
import (
|
|
"bytes"
|
|
"context"
|
|
"crypto/tls"
|
|
"crypto/x509"
|
|
"errors"
|
|
"net"
|
|
"net/url"
|
|
"time"
|
|
|
|
"github.com/cloudflare/cfssl/helpers"
|
|
"github.com/docker/swarmkit/api"
|
|
"github.com/docker/swarmkit/ca"
|
|
"github.com/docker/swarmkit/log"
|
|
"google.golang.org/grpc/codes"
|
|
"google.golang.org/grpc/status"
|
|
)
|
|
|
|
var minRootExpiration = 1 * helpers.OneYear
|
|
|
|
// determines whether an api.RootCA, api.RootRotation, or api.CAConfig has a signing key (local signer)
|
|
func hasSigningKey(a interface{}) bool {
|
|
switch b := a.(type) {
|
|
case *api.RootCA:
|
|
return len(b.CAKey) > 0
|
|
case *api.RootRotation:
|
|
return b != nil && len(b.CAKey) > 0
|
|
case *api.CAConfig:
|
|
return len(b.SigningCACert) > 0 && len(b.SigningCAKey) > 0
|
|
default:
|
|
panic("needsExternalCAs should be called something of type *api.RootCA, *api.RootRotation, or *api.CAConfig")
|
|
}
|
|
}
|
|
|
|
// Creates a cross-signed intermediate and new api.RootRotation object.
|
|
// This function assumes that the root cert and key and the external CAs have already been validated.
|
|
func newRootRotationObject(ctx context.Context, securityConfig *ca.SecurityConfig, apiRootCA *api.RootCA, newCARootCA ca.RootCA, extCAs []*api.ExternalCA, version uint64) (*api.RootCA, error) {
|
|
var (
|
|
rootCert, rootKey, crossSignedCert []byte
|
|
newRootHasSigner bool
|
|
err error
|
|
)
|
|
|
|
rootCert = newCARootCA.Certs
|
|
if s, err := newCARootCA.Signer(); err == nil {
|
|
rootCert, rootKey = s.Cert, s.Key
|
|
newRootHasSigner = true
|
|
}
|
|
|
|
// we have to sign with the original signer, not whatever is in the SecurityConfig's RootCA (which may have an intermediate signer, if
|
|
// a root rotation is already in progress)
|
|
switch {
|
|
case hasSigningKey(apiRootCA):
|
|
var oldRootCA ca.RootCA
|
|
oldRootCA, err = ca.NewRootCA(apiRootCA.CACert, apiRootCA.CACert, apiRootCA.CAKey, ca.DefaultNodeCertExpiration, nil)
|
|
if err == nil {
|
|
crossSignedCert, err = oldRootCA.CrossSignCACertificate(rootCert)
|
|
}
|
|
case !newRootHasSigner: // the original CA and the new CA both require external CAs
|
|
return nil, status.Errorf(codes.InvalidArgument, "rotating from one external CA to a different external CA is not supported")
|
|
default:
|
|
// We need the same credentials but to connect to the original URLs (in case we are in the middle of a root rotation already)
|
|
var urls []string
|
|
for _, c := range extCAs {
|
|
if c.Protocol == api.ExternalCA_CAProtocolCFSSL {
|
|
urls = append(urls, c.URL)
|
|
}
|
|
}
|
|
if len(urls) == 0 {
|
|
return nil, status.Errorf(codes.InvalidArgument,
|
|
"must provide an external CA for the current external root CA to generate a cross-signed certificate")
|
|
}
|
|
rootPool := x509.NewCertPool()
|
|
rootPool.AppendCertsFromPEM(apiRootCA.CACert)
|
|
|
|
externalCAConfig := ca.NewExternalCATLSConfig(securityConfig.ClientTLSCreds.Config().Certificates, rootPool)
|
|
externalCA := ca.NewExternalCA(nil, externalCAConfig, urls...)
|
|
crossSignedCert, err = externalCA.CrossSignRootCA(ctx, newCARootCA)
|
|
}
|
|
|
|
if err != nil {
|
|
log.G(ctx).WithError(err).Error("unable to generate a cross-signed certificate for root rotation")
|
|
return nil, status.Errorf(codes.Internal, "unable to generate a cross-signed certificate for root rotation")
|
|
}
|
|
|
|
copied := apiRootCA.Copy()
|
|
copied.RootRotation = &api.RootRotation{
|
|
CACert: rootCert,
|
|
CAKey: rootKey,
|
|
CrossSignedCACert: ca.NormalizePEMs(crossSignedCert),
|
|
}
|
|
copied.LastForcedRotation = version
|
|
return copied, nil
|
|
}
|
|
|
|
// Checks that a CA URL is connectable using the credentials we have and that its server certificate is signed by the
|
|
// root CA that we expect. This uses a TCP dialer rather than an HTTP client; because we have custom TLS configuration,
|
|
// if we wanted to use an HTTP client we'd have to create a new transport for every connection. The docs specify that
|
|
// Transports cache connections for future re-use, which could cause many open connections.
|
|
func validateExternalCAURL(dialer *net.Dialer, tlsOpts *tls.Config, caURL string) error {
|
|
parsed, err := url.Parse(caURL)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if parsed.Scheme != "https" {
|
|
return errors.New("invalid HTTP scheme")
|
|
}
|
|
host, port, err := net.SplitHostPort(parsed.Host)
|
|
if err != nil {
|
|
// It either has no port or is otherwise invalid (e.g. too many colons). If it's otherwise invalid the dialer
|
|
// will error later, so just assume it's no port and set the port to the default HTTPS port.
|
|
host = parsed.Host
|
|
port = "443"
|
|
}
|
|
|
|
conn, err := tls.DialWithDialer(dialer, "tcp", net.JoinHostPort(host, port), tlsOpts)
|
|
if conn != nil {
|
|
conn.Close()
|
|
}
|
|
return err
|
|
}
|
|
|
|
// Validates that there is at least 1 reachable, valid external CA for the given CA certificate. Returns true if there is, false otherwise.
|
|
// Requires that the wanted cert is already normalized.
|
|
func validateHasAtLeastOneExternalCA(ctx context.Context, externalCAs map[string][]*api.ExternalCA, securityConfig *ca.SecurityConfig,
|
|
wantedCert []byte, desc string) ([]*api.ExternalCA, error) {
|
|
specific, ok := externalCAs[string(wantedCert)]
|
|
if ok {
|
|
pool := x509.NewCertPool()
|
|
pool.AppendCertsFromPEM(wantedCert)
|
|
dialer := net.Dialer{Timeout: 5 * time.Second}
|
|
opts := tls.Config{
|
|
RootCAs: pool,
|
|
Certificates: securityConfig.ClientTLSCreds.Config().Certificates,
|
|
}
|
|
for i, ca := range specific {
|
|
if ca.Protocol == api.ExternalCA_CAProtocolCFSSL {
|
|
if err := validateExternalCAURL(&dialer, &opts, ca.URL); err != nil {
|
|
log.G(ctx).WithError(err).Warnf("external CA # %d is unreachable or invalid", i+1)
|
|
} else {
|
|
return specific, nil
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return nil, status.Errorf(codes.InvalidArgument, "there must be at least one valid, reachable external CA corresponding to the %s CA certificate", desc)
|
|
}
|
|
|
|
// validates that the list of external CAs have valid certs associated with them, and produce a mapping of subject/pubkey:external
|
|
// for later validation of required external CAs
|
|
func getNormalizedExtCAs(caConfig *api.CAConfig, normalizedCurrentRootCACert []byte) (map[string][]*api.ExternalCA, error) {
|
|
extCAs := make(map[string][]*api.ExternalCA)
|
|
|
|
for _, extCA := range caConfig.ExternalCAs {
|
|
associatedCert := normalizedCurrentRootCACert
|
|
// if no associated cert is provided, assume it's the current root cert
|
|
if len(extCA.CACert) > 0 {
|
|
associatedCert = ca.NormalizePEMs(extCA.CACert)
|
|
}
|
|
certKey := string(associatedCert)
|
|
extCAs[certKey] = append(extCAs[certKey], extCA)
|
|
}
|
|
|
|
return extCAs, nil
|
|
}
|
|
|
|
// validateAndUpdateCA validates a cluster's desired CA configuration spec, and returns a RootCA value on success representing
|
|
// current RootCA as it should be. Validation logic and return values are as follows:
|
|
// 1. Validates that the contents are complete - e.g. a signing key is not provided without a signing cert, and that external
|
|
// CAs are not removed if they are needed. Otherwise, returns an error.
|
|
// 2. If no desired signing cert or key are provided, then either:
|
|
// - we are happy with the current CA configuration (force rotation value has not changed), and we return the current RootCA
|
|
// object as is
|
|
// - we want to generate a new internal CA cert and key (force rotation value has changed), and we return the updated RootCA
|
|
// object
|
|
// 3. Signing cert and key have been provided: validate that these match (the cert and key match). Otherwise, return an error.
|
|
// 4. Return the updated RootCA object according to the following criteria:
|
|
// - If the desired cert is the same as the current CA cert then abort any outstanding rotations. The current signing key
|
|
// is replaced with the desired signing key (this could lets us switch between external->internal or internal->external
|
|
// without an actual CA rotation, which is not needed because any leaf cert issued with one CA cert can be validated using
|
|
// the second CA certificate).
|
|
// - If the desired cert is the same as the current to-be-rotated-to CA cert then a new root rotation is not needed. The
|
|
// current to-be-rotated-to signing key is replaced with the desired signing key (this could lets us switch between
|
|
// external->internal or internal->external without an actual CA rotation, which is not needed because any leaf cert
|
|
// issued with one CA cert can be validated using the second CA certificate).
|
|
// - Otherwise, start a new root rotation using the desired signing cert and desired signing key as the root rotation
|
|
// signing cert and key. If a root rotation is already in progress, just replace it and start over.
|
|
func validateCAConfig(ctx context.Context, securityConfig *ca.SecurityConfig, cluster *api.Cluster) (*api.RootCA, error) {
|
|
newConfig := cluster.Spec.CAConfig.Copy()
|
|
newConfig.SigningCACert = ca.NormalizePEMs(newConfig.SigningCACert) // ensure this is normalized before we use it
|
|
|
|
if len(newConfig.SigningCAKey) > 0 && len(newConfig.SigningCACert) == 0 {
|
|
return nil, status.Errorf(codes.InvalidArgument, "if a signing CA key is provided, the signing CA cert must also be provided")
|
|
}
|
|
|
|
normalizedRootCA := ca.NormalizePEMs(cluster.RootCA.CACert)
|
|
extCAs, err := getNormalizedExtCAs(newConfig, normalizedRootCA) // validate that the list of external CAs is not malformed
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var oldCertExtCAs []*api.ExternalCA
|
|
if !hasSigningKey(&cluster.RootCA) {
|
|
|
|
// If we are going from external -> internal, but providing the external CA's signing key,
|
|
// then we don't need to validate any external CAs. We can in fact abort any outstanding root
|
|
// rotations if we are just adding a key. Because we have a key, we don't care if there are
|
|
// no external CAs matching the certificate.
|
|
if bytes.Equal(normalizedRootCA, newConfig.SigningCACert) && hasSigningKey(newConfig) {
|
|
// validate that the key and cert indeed match - if they don't then just fail now rather
|
|
// than go through all the external CA URLs, which is a more expensive operation
|
|
if _, err := ca.NewRootCA(newConfig.SigningCACert, newConfig.SigningCACert, newConfig.SigningCAKey, ca.DefaultNodeCertExpiration, nil); err != nil {
|
|
return nil, err
|
|
}
|
|
copied := cluster.RootCA.Copy()
|
|
copied.CAKey = newConfig.SigningCAKey
|
|
copied.RootRotation = nil
|
|
copied.LastForcedRotation = newConfig.ForceRotate
|
|
return copied, nil
|
|
}
|
|
|
|
oldCertExtCAs, err = validateHasAtLeastOneExternalCA(ctx, extCAs, securityConfig, normalizedRootCA, "current")
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
// if the desired CA cert and key are not set, then we are happy with the current root CA configuration, unless
|
|
// the ForceRotate version has changed
|
|
if len(newConfig.SigningCACert) == 0 {
|
|
if cluster.RootCA.LastForcedRotation != newConfig.ForceRotate {
|
|
newRootCA, err := ca.CreateRootCA(ca.DefaultRootCN)
|
|
if err != nil {
|
|
return nil, status.Errorf(codes.Internal, err.Error())
|
|
}
|
|
return newRootRotationObject(ctx, securityConfig, &cluster.RootCA, newRootCA, oldCertExtCAs, newConfig.ForceRotate)
|
|
}
|
|
|
|
// we also need to make sure that if the current root rotation requires an external CA, those external CAs are
|
|
// still valid
|
|
if cluster.RootCA.RootRotation != nil && !hasSigningKey(cluster.RootCA.RootRotation) {
|
|
_, err := validateHasAtLeastOneExternalCA(ctx, extCAs, securityConfig, ca.NormalizePEMs(cluster.RootCA.RootRotation.CACert), "next")
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
return &cluster.RootCA, nil // no change, return as is
|
|
}
|
|
|
|
// A desired cert and maybe key were provided - we need to make sure the cert and key (if provided) match.
|
|
var signingCert []byte
|
|
if hasSigningKey(newConfig) {
|
|
signingCert = newConfig.SigningCACert
|
|
}
|
|
newRootCA, err := ca.NewRootCA(newConfig.SigningCACert, signingCert, newConfig.SigningCAKey, ca.DefaultNodeCertExpiration, nil)
|
|
if err != nil {
|
|
return nil, status.Errorf(codes.InvalidArgument, err.Error())
|
|
}
|
|
|
|
if len(newRootCA.Pool.Subjects()) != 1 {
|
|
return nil, status.Errorf(codes.InvalidArgument, "the desired CA certificate cannot contain multiple certificates")
|
|
}
|
|
|
|
parsedCert, err := helpers.ParseCertificatePEM(newConfig.SigningCACert)
|
|
if err != nil {
|
|
return nil, status.Errorf(codes.InvalidArgument, "could not parse the desired CA certificate")
|
|
}
|
|
|
|
// The new certificate's expiry must be at least one year away
|
|
if parsedCert.NotAfter.Before(time.Now().Add(minRootExpiration)) {
|
|
return nil, status.Errorf(codes.InvalidArgument, "CA certificate expires too soon")
|
|
}
|
|
|
|
if !hasSigningKey(newConfig) {
|
|
if _, err := validateHasAtLeastOneExternalCA(ctx, extCAs, securityConfig, newConfig.SigningCACert, "desired"); err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
// check if we can abort any existing root rotations
|
|
if bytes.Equal(normalizedRootCA, newConfig.SigningCACert) {
|
|
copied := cluster.RootCA.Copy()
|
|
copied.CAKey = newConfig.SigningCAKey
|
|
copied.RootRotation = nil
|
|
copied.LastForcedRotation = newConfig.ForceRotate
|
|
return copied, nil
|
|
}
|
|
|
|
// check if this is the same desired cert as an existing root rotation
|
|
if r := cluster.RootCA.RootRotation; r != nil && bytes.Equal(ca.NormalizePEMs(r.CACert), newConfig.SigningCACert) {
|
|
copied := cluster.RootCA.Copy()
|
|
copied.RootRotation.CAKey = newConfig.SigningCAKey
|
|
copied.LastForcedRotation = newConfig.ForceRotate
|
|
return copied, nil
|
|
}
|
|
|
|
// ok, everything's different; we have to begin a new root rotation which means generating a new cross-signed cert
|
|
return newRootRotationObject(ctx, securityConfig, &cluster.RootCA, newRootCA, oldCertExtCAs, newConfig.ForceRotate)
|
|
}
|