ca: remove one call to provider.ActiveRoot

ActiveRoot should not be called from the secondary DC, because there
should not be a requirement to run the same Vault instance in a
secondary DC. SignIntermediate is called in a secondary DC, so it should
not call ActiveRoot

We would also like to change the interface of ActiveRoot so that we can
support using an intermediate cert as the primary CA in Consul. In
preparation for making that change I am reducing the number of calls to
ActiveRoot, so that there are fewer code paths to modify when the
interface changes.

This change required a change to the mockCAServerDelegate we use in
tests. It was returning the RootCert for SignIntermediate, but that is
not an accurate fake of production. In production this would also be a
separate cert.

agent/consul/leader_connect_ca.go

@@ -1463,28 +1463,22 @@ func (c *CAManager) SignCertificate(csr *x509.CertificateRequest, spiffeID conne
 
 	connect.HackSANExtensionForCSR(csr)
 
-	root, err := provider.ActiveRoot()
-	if err != nil {
-		return nil, err
-	}
 	// Check if the root expired before using it to sign.
-	err = c.checkExpired(root)
+	// TODO: we store NotBefore and NotAfter on this struct, so we could avoid
+	// parsing the cert here.
+	err = c.checkExpired(caRoot.RootCert)
 	if err != nil {
 		return nil, fmt.Errorf("root expired: %w", err)
 	}
 
-	inter, err := provider.ActiveIntermediate()
+	if c.isIntermediateUsedToSignLeaf() && len(caRoot.IntermediateCerts) > 0 {
-	if err != nil {
+		inter := caRoot.IntermediateCerts[len(caRoot.IntermediateCerts)-1]
-		return nil, err
+		if err := c.checkExpired(inter); err != nil {
-	}
-	// Check if the intermediate expired before using it to sign.
-	err = c.checkExpired(inter)
-	if err != nil {
 			return nil, fmt.Errorf("intermediate expired: %w", err)
 		}
+	}
 
 	// All seems to be in order, actually sign it.
-
 	pem, err := provider.Sign(csr)
 	if err == ca.ErrRateLimited {
 		return nil, ErrRateLimited

agent/consul/leader_connect_ca_test.go

@@ -12,6 +12,7 @@ import (
 	"fmt"
 	"math/big"
 	"net/rpc"
+	"net/url"
 	"testing"
 	"time"
 
@@ -135,6 +136,7 @@ type mockCAServerDelegate struct {
 	config                *Config
 	store                 *state.Store
 	primaryRoot           *structs.CARoot
+	secondaryIntermediate string
 	callbackCh            chan string
 }
 
@@ -198,7 +200,7 @@ func (m *mockCAServerDelegate) forwardDC(method, dc string, args interface{}, re
 		roots.ActiveRootID = m.primaryRoot.ID
 	case "ConnectCA.SignIntermediate":
 		r := reply.(*string)
-		*r = m.primaryRoot.RootCert
+		*r = m.secondaryIntermediate
 	default:
 		return fmt.Errorf("received call to unsupported method %q", method)
 	}
@@ -305,13 +307,14 @@ func initTestManager(t *testing.T, manager *CAManager, delegate *mockCAServerDel
 }
 
 func TestCAManager_Initialize(t *testing.T) {
-
 	conf := DefaultConfig()
 	conf.ConnectEnabled = true
 	conf.PrimaryDatacenter = "dc1"
 	conf.Datacenter = "dc2"
 	delegate := NewMockCAServerDelegate(t, conf)
+	delegate.secondaryIntermediate = delegate.primaryRoot.RootCert
 	manager := NewCAManager(delegate, nil, testutil.Logger(t), conf)
+
 	manager.providerShim = &mockCAProvider{
 		callbackCh: delegate.callbackCh,
 		rootPEM:    delegate.primaryRoot.RootCert,
@@ -356,6 +359,7 @@ func TestCAManager_UpdateConfigWhileRenewIntermediate(t *testing.T) {
 	conf.PrimaryDatacenter = "dc1"
 	conf.Datacenter = "dc2"
 	delegate := NewMockCAServerDelegate(t, conf)
+	delegate.secondaryIntermediate = delegate.primaryRoot.RootCert
 	manager := NewCAManager(delegate, nil, testutil.Logger(t), conf)
 	manager.providerShim = &mockCAProvider{
 		callbackCh: delegate.callbackCh,
@@ -447,6 +451,8 @@ func TestCAManager_SignCertificate_WithExpiredCert(t *testing.T) {
 			intermediatePEM := generateCertPEM(t, caPrivKey, arg.notBeforeIntermediate, arg.notAfterIntermediate)
 
 			delegate := NewMockCAServerDelegate(t, conf)
+			delegate.primaryRoot.RootCert = rootPEM
+			delegate.secondaryIntermediate = intermediatePEM
 			manager := NewCAManager(delegate, nil, testutil.Logger(t), conf)
 
 			manager.providerShim = &mockCAProvider{
@@ -458,14 +464,13 @@ func TestCAManager_SignCertificate_WithExpiredCert(t *testing.T) {
 
 			// Simulate Wait half the TTL for the cert to need renewing.
 			manager.timeNow = func() time.Time {
-				return time.Now().Add(500 * time.Millisecond)
+				return time.Now().UTC().Add(500 * time.Millisecond)
 			}
 
 			// Call RenewIntermediate and then confirm the RPCs and provider calls
 			// happen in the expected order.
 
 			_, err := manager.SignCertificate(&x509.CertificateRequest{}, &connect.SpiffeIDAgent{})
-
 			if arg.isError {
 				require.Error(t, err)
 				require.Contains(t, err.Error(), arg.errorMsg)
@@ -494,6 +499,7 @@ func generateCertPEM(t *testing.T, caPrivKey *rsa.PrivateKey, notBefore time.Tim
 		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth},
 		KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
 		BasicConstraintsValid: true,
+		URIs:                  []*url.URL{connect.SpiffeIDAgent{Host: "foo"}.URI()},
 	}
 
 	caBytes, err := x509.CreateCertificate(rand.Reader, ca, ca, &caPrivKey.PublicKey, caPrivKey)