Add experimental message in logs

Related to smallstep/ca-component#142

Gopkg.toml

@@ -51,6 +51,10 @@
   name = "gopkg.in/square/go-jose.v2"
   version = "2.3.1"
 
+[[constraint]]
+  branch = "master"
+  name = "github.com/google/certificate-transparency-go"
+
 [prune]
   go-tests = true
   unused-packages = true

authority/authority.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/smallstep/certificates/authority/provisioner"
+	"github.com/smallstep/certificates/ct"
 	"github.com/smallstep/certificates/db"
 	"github.com/smallstep/cli/crypto/pemutil"
 	"github.com/smallstep/cli/crypto/x509util"
@@ -30,6 +31,7 @@ type Authority struct {
 	startTime            time.Time
 	provisioners         *provisioner.Collection
 	db                   db.AuthDB
+	ctClient             ct.Client
 	// Do not re-initialize
 	initOnce bool
 }
@@ -52,10 +54,19 @@ func New(config *Config, opts ...Option) (*Authority, error) {
 		return nil, err
 	}
 
+	var ctClient ct.Client
+	// only first one is supported at the moment.
+	if len(config.CTs) > 0 {
+		if ctClient, err = ct.New(config.CTs[0]); err != nil {
+			return nil, err
+		}
+	}
+
 	var a = &Authority{
 		config:       config,
 		certificates: new(sync.Map),
 		provisioners: provisioner.NewCollection(config.getAudiences()),
+		ctClient:     ctClient,
 	}
 	for _, opt := range opts {
 		opt(a)

authority/config.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/smallstep/certificates/authority/provisioner"
+	"github.com/smallstep/certificates/ct"
 	"github.com/smallstep/certificates/db"
 	"github.com/smallstep/cli/crypto/tlsutil"
 	"github.com/smallstep/cli/crypto/x509util"
@@ -59,6 +60,7 @@ type Config struct {
 	AuthorityConfig  *AuthConfig         `json:"authority,omitempty"`
 	TLS              *tlsutil.TLSOptions `json:"tls,omitempty"`
 	Password         string              `json:"password,omitempty"`
+	CTs              []ct.Config         `json:"cts"`
 }
 
 // AuthConfig represents the configuration options for the authority.
@@ -181,6 +183,14 @@ func (c *Config) Validate() error {
 		c.TLS.Renegotiation = c.TLS.Renegotiation || DefaultTLSOptions.Renegotiation
 	}
 
+	if len(c.CTs) > 0 {
+		for _, ct := range c.CTs {
+			if err := ct.Validate(); err != nil {
+				return err
+			}
+		}
+	}
+
 	return c.AuthorityConfig.Validate(c.getAudiences())
 }
 

authority/tls.go

@@ -23,7 +23,12 @@ func (a *Authority) GetTLSOptions() *tlsutil.TLSOptions {
 	return a.config.TLS
 }
 
-var oidAuthorityKeyIdentifier = asn1.ObjectIdentifier{2, 5, 29, 35}
+var (
+	oidAuthorityKeyIdentifier = asn1.ObjectIdentifier{2, 5, 29, 35}
+	// Certificate transparency extensions OIDs
+	ctPoisonOID                     = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 11129, 2, 4, 3}
+	ctSigendCertificateTimestampOID = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 11129, 2, 4, 2}
+)
 
 func withDefaultASN1DN(def *x509util.ASN1DN) x509util.WithOption {
 	return func(p x509util.Profile) error {
@@ -79,6 +84,11 @@ func (a *Authority) Sign(csr *x509.CertificateRequest, signOpts provisioner.Opti
 		}
 	}
 
+	// Add CT Poison extension
+	if a.ctClient != nil {
+		mods = append(mods, x509util.WithCTPoison())
+	}
+
 	if err := csr.CheckSignature(); err != nil {
 		return nil, nil, &apiError{errors.Wrap(err, "sign: invalid certificate request"),
 			http.StatusBadRequest, errContext}
@@ -101,6 +111,25 @@ func (a *Authority) Sign(csr *x509.CertificateRequest, signOpts provisioner.Opti
 			http.StatusInternalServerError, errContext}
 	}
 
+	if a.ctClient != nil {
+		// Submit precertificate chain and get SCTs
+		scts, err := a.ctClient.GetSCTs(crtBytes, issIdentity.Crt.Raw)
+		if err != nil {
+			return nil, nil, &apiError{errors.Wrap(err, "sign: error getting SCTs for certificate"),
+				http.StatusBadGateway, errContext}
+		}
+
+		// Remove ct poison extension and add sct extension
+		leaf.RemoveExtension(ctPoisonOID)
+		leaf.AddExtension(scts.GetExtension())
+
+		// Recreate final certificate
+		if crtBytes, err = leaf.CreateCertificate(); err != nil {
+			return nil, nil, &apiError{errors.Wrap(err, "sign: error creating final leaf certificate"),
+				http.StatusInternalServerError, errContext}
+		}
+	}
+
 	serverCert, err := x509.ParseCertificate(crtBytes)
 	if err != nil {
 		return nil, nil, &apiError{errors.Wrap(err, "sign: error parsing new leaf certificate"),
@@ -120,6 +149,14 @@ func (a *Authority) Sign(csr *x509.CertificateRequest, signOpts provisioner.Opti
 		}
 	}
 
+	if a.ctClient != nil {
+		// Submit final certificate chain
+		if _, err := a.ctClient.SubmitToLogs(serverCert.Raw, caCert.Raw); err != nil {
+			return nil, nil, &apiError{errors.Wrap(err, "sign: error submitting final certificate to ct logs"),
+				http.StatusBadGateway, errContext}
+		}
+	}
+
 	return serverCert, caCert, nil
 }
 
@@ -178,17 +215,45 @@ func (a *Authority) Renew(oldCert *x509.Certificate) (*x509.Certificate, *x509.C
 		}
 	}
 
-	leaf, err := x509util.NewLeafProfileWithTemplate(newCert,
-		issIdentity.Crt, issIdentity.Key)
+	opts := []x509util.WithOption{}
+	// Add CT Poison extension
+	if a.ctClient != nil {
+		opts = append(opts, x509util.WithCTPoison())
+	}
+
+	leaf, err := x509util.NewLeafProfileWithTemplate(newCert, issIdentity.Crt, issIdentity.Key, opts...)
 	if err != nil {
 		return nil, nil, &apiError{err, http.StatusInternalServerError, apiCtx{}}
 	}
+
+	// Remove previous SCTs if any
+	leaf.RemoveExtension(ctSigendCertificateTimestampOID)
+
 	crtBytes, err := leaf.CreateCertificate()
 	if err != nil {
 		return nil, nil, &apiError{errors.Wrap(err, "error renewing certificate from existing server certificate"),
 			http.StatusInternalServerError, apiCtx{}}
 	}
 
+	if a.ctClient != nil {
+		// Submit precertificate chain and get SCTs
+		scts, err := a.ctClient.GetSCTs(crtBytes, issIdentity.Crt.Raw)
+		if err != nil {
+			return nil, nil, &apiError{errors.Wrap(err, "renew: error getting SCTs for certificate"),
+				http.StatusBadGateway, apiCtx{}}
+		}
+
+		// Remove ct poison extension and add sct extension
+		leaf.RemoveExtension(ctPoisonOID)
+		leaf.AddExtension(scts.GetExtension())
+
+		// Recreate final certificate
+		if crtBytes, err = leaf.CreateCertificate(); err != nil {
+			return nil, nil, &apiError{errors.Wrap(err, "renew: error creating final leaf certificate"),
+				http.StatusInternalServerError, apiCtx{}}
+		}
+	}
+
 	serverCert, err := x509.ParseCertificate(crtBytes)
 	if err != nil {
 		return nil, nil, &apiError{errors.Wrap(err, "error parsing new server certificate"),
@@ -200,6 +265,14 @@ func (a *Authority) Renew(oldCert *x509.Certificate) (*x509.Certificate, *x509.C
 			http.StatusInternalServerError, apiCtx{}}
 	}
 
+	if a.ctClient != nil {
+		// Submit final certificate chain
+		if _, err := a.ctClient.SubmitToLogs(serverCert.Raw, caCert.Raw); err != nil {
+			return nil, nil, &apiError{errors.Wrap(err, "renew: error submitting final certificate to ct logs"),
+				http.StatusBadGateway, apiCtx{}}
+		}
+	}
+
 	return serverCert, caCert, nil
 }
 
@@ -278,9 +351,17 @@ func (a *Authority) Revoke(opts *RevokeOptions) error {
 
 // GetTLSCertificate creates a new leaf certificate to be used by the CA HTTPS server.
 func (a *Authority) GetTLSCertificate() (*tls.Certificate, error) {
+	opts := []x509util.WithOption{
+		x509util.WithHosts(strings.Join(a.config.DNSNames, ",")),
+	}
+
+	// Add CT Poison extension
+	if a.ctClient != nil {
+		opts = append(opts, x509util.WithCTPoison())
+	}
+
 	profile, err := x509util.NewLeafProfile("Step Online CA",
-		a.intermediateIdentity.Crt, a.intermediateIdentity.Key,
-		x509util.WithHosts(strings.Join(a.config.DNSNames, ",")))
+		a.intermediateIdentity.Crt, a.intermediateIdentity.Key, opts...)
 	if err != nil {
 		return nil, err
 	}
@@ -290,6 +371,23 @@ func (a *Authority) GetTLSCertificate() (*tls.Certificate, error) {
 		return nil, err
 	}
 
+	if a.ctClient != nil {
+		// Submit precertificate chain and get SCTs
+		scts, err := a.ctClient.GetSCTs(crtBytes, a.intermediateIdentity.Crt.Raw)
+		if err != nil {
+			return nil, errors.Wrap(err, "error getting SCTs for certificate")
+		}
+
+		// Remove ct poison extension and add sct extension
+		profile.RemoveExtension(ctPoisonOID)
+		profile.AddExtension(scts.GetExtension())
+
+		// Recreate final certificate
+		if crtBytes, err = profile.CreateCertificate(); err != nil {
+			return nil, errors.Wrap(err, "error creating final leaf certificate")
+		}
+	}
+
 	keyPEM, err := pemutil.Serialize(profile.SubjectPrivateKey())
 	if err != nil {
 		return nil, err
@@ -306,6 +404,14 @@ func (a *Authority) GetTLSCertificate() (*tls.Certificate, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	if a.ctClient != nil {
+		// Submit final certificate chain
+		if _, err := a.ctClient.SubmitToLogs(crtBytes, intermediatePEM.Bytes); err != nil {
+			return nil, errors.Wrap(err, "error submitting final certificate to ct logs")
+		}
+	}
+
 	tlsCrt, err := tls.X509KeyPair(append(crtPEM,
 		pem.EncodeToMemory(intermediatePEM)...),
 		pem.EncodeToMemory(keyPEM))

ca/renew.go

@@ -72,6 +72,8 @@ func NewTLSRenewer(cert *tls.Certificate, fn RenewFunc, opts ...tlsRenewerOption
 	if r.renewJitter == 0 {
 		r.renewJitter = period / 20
 	}
+	// Initialize certNotAfter
+	r.certNotAfter = cert.Leaf.NotAfter.Add(-1 * time.Minute)
 
 	return r, nil
 }

ct/ct.go

@@ -0,0 +1,222 @@
+package ct
+
+import (
+	"context"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"encoding/pem"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"time"
+
+	ct "github.com/google/certificate-transparency-go"
+	"github.com/google/certificate-transparency-go/client"
+	"github.com/google/certificate-transparency-go/jsonclient"
+	cttls "github.com/google/certificate-transparency-go/tls"
+	ctx509 "github.com/google/certificate-transparency-go/x509"
+	"github.com/pkg/errors"
+)
+
+var (
+	oidExtensionCTPoison              = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 11129, 2, 4, 3}
+	oidSignedCertificateTimestampList = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 11129, 2, 4, 2}
+)
+
+// Config represents the configuration for the certificate authority client.
+type Config struct {
+	URI           string    `json:"uri"`
+	Key           string    `json:"key"`
+	NotAfterStart time.Time `json:"notAfterStart,omitempty"`
+	NotAfterLimit time.Time `json:"notAfterLimit,omitempty"`
+}
+
+// Validate validates the ct configuration.
+func (c *Config) Validate() error {
+	switch {
+	case c.URI == "":
+		return errors.New("ct uri cannot be empty")
+	case c.Key == "":
+		return errors.New("ct key cannot be empty")
+	default:
+		return nil
+	}
+}
+
+// Client is the interface used to communicate with the certificate transparency logs.
+type Client interface {
+	GetSCTs(asn1Data ...[]byte) (*SCT, error)
+	SubmitToLogs(asn1Data ...[]byte) (*SCT, error)
+}
+
+type logClient interface {
+	AddChain(ctx context.Context, chain []ct.ASN1Cert) (*ct.SignedCertificateTimestamp, error)
+	AddPreChain(ctx context.Context, chain []ct.ASN1Cert) (*ct.SignedCertificateTimestamp, error)
+}
+
+// SCT represents a Signed Certificate Timestamp.
+type SCT struct {
+	LogURL string
+	SCT    *ct.SignedCertificateTimestamp
+}
+
+// GetExtension returns the extension representing an SCT that will be added to
+// a certificate.
+func (t *SCT) GetExtension() pkix.Extension {
+	val, err := cttls.Marshal(*t.SCT)
+	if err != nil {
+		panic(err)
+	}
+	value, err := cttls.Marshal(ctx509.SignedCertificateTimestampList{
+		SCTList: []ctx509.SerializedSCT{
+			{Val: val},
+		},
+	})
+	if err != nil {
+		panic(err)
+	}
+	rawValue, err := asn1.Marshal(value)
+	if err != nil {
+		panic(err)
+	}
+	return pkix.Extension{
+		Id:       oidSignedCertificateTimestampList,
+		Critical: false,
+		Value:    rawValue,
+	}
+}
+
+// AddPoisonExtension appends the ct poison extension to the given certificate.
+func AddPoisonExtension(cert *x509.Certificate) {
+	cert.Extensions = append(cert.Extensions, pkix.Extension{
+		Id:       oidExtensionCTPoison,
+		Critical: true,
+	})
+}
+
+// ClientImpl is the implementation of a certificate transparency Client.
+type ClientImpl struct {
+	config    Config
+	logClient logClient
+	timeout   time.Duration
+}
+
+// New creates a new Client
+func New(c Config) (*ClientImpl, error) {
+	der, err := readPublicKey(c.Key)
+	if err != nil {
+		return nil, err
+	}
+
+	// Initialize ct client
+	logClient, err := client.New(c.URI, &http.Client{}, jsonclient.Options{
+		PublicKeyDER: der,
+		UserAgent:    "smallstep certificates",
+	})
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to create client to %s", c.URI)
+	}
+
+	// Validate connection
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	if _, err := logClient.GetSTH(ctx); err != nil {
+		return nil, errors.Wrapf(err, "failed to connect to %s", c.URI)
+	}
+	log.Printf("connecting to CT log %s", c.URI)
+	log.Println("CT support is experimental and can change at any time")
+
+	return &ClientImpl{
+		config:    c,
+		logClient: logClient,
+		timeout:   30 * time.Second,
+	}, nil
+}
+
+// GetSCTs submit the precertificate to the logs and returns the list of SCTs to
+// embed into the certificate.
+func (c *ClientImpl) GetSCTs(asn1Data ...[]byte) (*SCT, error) {
+	chain := chainFromDERs(asn1Data)
+	ctx, cancel := context.WithTimeout(context.Background(), c.timeout)
+	defer cancel()
+	sct, err := c.logClient.AddPreChain(ctx, chain)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get SCT from %s", c.config.URI)
+	}
+	logLeafHash("AddPreChain", asn1Data, sct, true)
+	return &SCT{
+		LogURL: c.config.URI,
+		SCT:    sct,
+	}, nil
+}
+
+// SubmitToLogs submits the certificate to the certificate transparency logs.
+func (c *ClientImpl) SubmitToLogs(asn1Data ...[]byte) (*SCT, error) {
+	chain := chainFromDERs(asn1Data)
+	ctx, cancel := context.WithTimeout(context.Background(), c.timeout)
+	defer cancel()
+	sct, err := c.logClient.AddChain(ctx, chain)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed submit certificate to %s", c.config.URI)
+	}
+	logLeafHash("AddChain", asn1Data, sct, false)
+	return &SCT{
+		LogURL: c.config.URI,
+		SCT:    sct,
+	}, nil
+}
+
+// readPublicKey extracts the DER from the given file.
+func readPublicKey(filename string) ([]byte, error) {
+	data, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error reading %s", filename)
+	}
+	block, rest := pem.Decode(data)
+	if block == nil || len(rest) > 0 {
+		return nil, errors.Wrapf(err, "invalid public key %s", filename)
+	}
+	return block.Bytes, nil
+}
+
+func chainFromDERs(asn1Data [][]byte) []ct.ASN1Cert {
+	var chain []ct.ASN1Cert
+	for _, der := range asn1Data {
+		chain = append(chain, ct.ASN1Cert{Data: der})
+	}
+	return chain
+}
+
+func logLeafHash(op string, asn1Data [][]byte, sct *ct.SignedCertificateTimestamp, isPrecert bool) {
+	var etype ct.LogEntryType
+	if isPrecert {
+		etype = ct.PrecertLogEntryType
+	} else {
+		etype = ct.X509LogEntryType
+	}
+
+	chain := make([]*ctx509.Certificate, len(asn1Data))
+	for i := range asn1Data {
+		cert, err := ctx509.ParseCertificate(asn1Data[i])
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		chain[i] = cert
+	}
+
+	leafEntry, err := ct.MerkleTreeLeafFromChain(chain, etype, sct.Timestamp)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	leafHash, err := ct.LeafHashForLeaf(leafEntry)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	log.Printf("Op: %s, LogID: %x, LeafHash: %x, Timestamp: %d\n", op, sct.LogID.KeyID[:], leafHash, sct.Timestamp)
+}

ct/multilog.go

@@ -0,0 +1,84 @@
+package ct
+
+// MultiLog is the interface used to send certificates to multiple logs.
+type MultiLog interface {
+	GetSCTs(asn1Data ...[]byte) ([]*SCT, error)
+	SubmitToLogs(asn1Data ...[]byte) ([]*SCT, error)
+}
+
+// MultiLogImpl is the implementation used to send certificates to multiple
+// logs.
+type MultiLogImpl struct {
+	clients []Client
+	configs []Config
+}
+
+type result struct {
+	sct *SCT
+	err error
+	uri string
+}
+
+// NewMultiLog returns a MultiLog with the given configuration.
+func NewMultiLog(config []Config) (MultiLog, error) {
+	ml := new(MultiLogImpl)
+	for _, cfg := range config {
+		client, err := New(cfg)
+		if err != nil {
+			return nil, err
+		}
+		ml.clients = append(ml.clients, client)
+	}
+	return ml, nil
+}
+
+// GetSCTs submit the precertificate to the logs and returns the list of SCTs to
+// embed into the certificate.
+func (c *MultiLogImpl) GetSCTs(asn1Data ...[]byte) (scts []*SCT, err error) {
+	results := make(chan result, len(c.clients))
+	for i := range c.clients {
+		client := c.clients[i]
+		config := c.configs[i]
+		go func() {
+			sct, err := client.GetSCTs(asn1Data...)
+			results <- result{sct: sct, err: err, uri: config.URI}
+		}()
+	}
+
+	for i := 0; i < len(c.clients); i++ {
+		res := <-results
+		switch {
+		case res.sct != nil:
+			scts = append(scts, res.sct)
+		case res.err != nil && err != nil:
+			err = res.err
+		}
+	}
+
+	return scts, err
+}
+
+// SubmitToLogs submits the certificate to the certificate transparency logs.
+func (c *MultiLogImpl) SubmitToLogs(asn1Data ...[]byte) (scts []*SCT, err error) {
+	results := make(chan result, len(c.clients))
+	for i := range c.clients {
+		client := c.clients[i]
+		config := c.configs[i]
+		go func() {
+			sct, err := client.SubmitToLogs(asn1Data...)
+			results <- result{sct: sct, err: err, uri: config.URI}
+		}()
+	}
+
+	for i := 0; i < len(c.clients); i++ {
+		res := <-results
+		switch {
+		case res.sct != nil:
+			scts = append(scts, res.sct)
+		case res.err != nil && err != nil:
+			err = res.err
+		}
+	}
+
+	return scts, err
+}