package authority import ( "context" "crypto" "crypto/tls" "crypto/x509" "encoding/asn1" "encoding/base64" "encoding/json" "encoding/pem" "fmt" "net/http" "strings" "time" "github.com/pkg/errors" "github.com/smallstep/certificates/authority/config" "github.com/smallstep/certificates/authority/provisioner" casapi "github.com/smallstep/certificates/cas/apiv1" "github.com/smallstep/certificates/db" "github.com/smallstep/certificates/errs" "go.step.sm/crypto/jose" "go.step.sm/crypto/keyutil" "go.step.sm/crypto/pemutil" "go.step.sm/crypto/x509util" "golang.org/x/crypto/ssh" ) // GetTLSOptions returns the tls options configured. func (a *Authority) GetTLSOptions() *config.TLSOptions { return a.config.TLS } var oidAuthorityKeyIdentifier = asn1.ObjectIdentifier{2, 5, 29, 35} var oidSubjectKeyIdentifier = asn1.ObjectIdentifier{2, 5, 29, 14} func withDefaultASN1DN(def *config.ASN1DN) provisioner.CertificateModifierFunc { return func(crt *x509.Certificate, opts provisioner.SignOptions) error { if def == nil { return errors.New("default ASN1DN template cannot be nil") } if len(crt.Subject.Country) == 0 && def.Country != "" { crt.Subject.Country = append(crt.Subject.Country, def.Country) } if len(crt.Subject.Organization) == 0 && def.Organization != "" { crt.Subject.Organization = append(crt.Subject.Organization, def.Organization) } if len(crt.Subject.OrganizationalUnit) == 0 && def.OrganizationalUnit != "" { crt.Subject.OrganizationalUnit = append(crt.Subject.OrganizationalUnit, def.OrganizationalUnit) } if len(crt.Subject.Locality) == 0 && def.Locality != "" { crt.Subject.Locality = append(crt.Subject.Locality, def.Locality) } if len(crt.Subject.Province) == 0 && def.Province != "" { crt.Subject.Province = append(crt.Subject.Province, def.Province) } if len(crt.Subject.StreetAddress) == 0 && def.StreetAddress != "" { crt.Subject.StreetAddress = append(crt.Subject.StreetAddress, def.StreetAddress) } if crt.Subject.SerialNumber == "" && def.SerialNumber != "" { crt.Subject.SerialNumber = def.SerialNumber } if crt.Subject.CommonName == "" && def.CommonName != "" { crt.Subject.CommonName = def.CommonName } return nil } } // Sign creates a signed certificate from a certificate signing request. func (a *Authority) Sign(csr *x509.CertificateRequest, signOpts provisioner.SignOptions, extraOpts ...provisioner.SignOption) ([]*x509.Certificate, error) { var ( certOptions []x509util.Option certValidators []provisioner.CertificateValidator certModifiers []provisioner.CertificateModifier certEnforcers []provisioner.CertificateEnforcer ) opts := []interface{}{errs.WithKeyVal("csr", csr), errs.WithKeyVal("signOptions", signOpts)} if err := csr.CheckSignature(); err != nil { return nil, errs.ApplyOptions( errs.BadRequestErr(err, "invalid certificate request"), opts..., ) } // Set backdate with the configured value signOpts.Backdate = a.config.AuthorityConfig.Backdate.Duration for _, op := range extraOpts { switch k := op.(type) { // Adds new options to NewCertificate case provisioner.CertificateOptions: certOptions = append(certOptions, k.Options(signOpts)...) // Validate the given certificate request. case provisioner.CertificateRequestValidator: if err := k.Valid(csr); err != nil { return nil, errs.ApplyOptions( errs.ForbiddenErr(err, "error validating certificate"), opts..., ) } // Validates the unsigned certificate template. case provisioner.CertificateValidator: certValidators = append(certValidators, k) // Modifies a certificate before validating it. case provisioner.CertificateModifier: certModifiers = append(certModifiers, k) // Modifies a certificate after validating it. case provisioner.CertificateEnforcer: certEnforcers = append(certEnforcers, k) default: return nil, errs.InternalServer("authority.Sign; invalid extra option type %T", append([]interface{}{k}, opts...)...) } } cert, err := x509util.NewCertificate(csr, certOptions...) if err != nil { if _, ok := err.(*x509util.TemplateError); ok { return nil, errs.ApplyOptions( errs.BadRequestErr(err, err.Error()), errs.WithKeyVal("csr", csr), errs.WithKeyVal("signOptions", signOpts), ) } // explicitly check for unmarshaling errors, which are most probably caused by JSON template (syntax) errors if strings.HasPrefix(err.Error(), "error unmarshaling certificate") { return nil, errs.InternalServerErr(templatingError(err), errs.WithKeyVal("csr", csr), errs.WithKeyVal("signOptions", signOpts), errs.WithMessage("error applying certificate template"), ) } return nil, errs.Wrap(http.StatusInternalServerError, err, "authority.Sign", opts...) } // Certificate modifiers before validation leaf := cert.GetCertificate() // Set default subject if err := withDefaultASN1DN(a.config.AuthorityConfig.Template).Modify(leaf, signOpts); err != nil { return nil, errs.ApplyOptions( errs.ForbiddenErr(err, "error creating certificate"), opts..., ) } for _, m := range certModifiers { if err := m.Modify(leaf, signOpts); err != nil { return nil, errs.ApplyOptions( errs.ForbiddenErr(err, "error creating certificate"), opts..., ) } } // Certificate validation. for _, v := range certValidators { if err := v.Valid(leaf, signOpts); err != nil { return nil, errs.ApplyOptions( errs.ForbiddenErr(err, "error validating certificate"), opts..., ) } } // Certificate modifiers after validation for _, m := range certEnforcers { if err := m.Enforce(leaf); err != nil { return nil, errs.ApplyOptions( errs.ForbiddenErr(err, "error creating certificate"), opts..., ) } } lifetime := leaf.NotAfter.Sub(leaf.NotBefore.Add(signOpts.Backdate)) resp, err := a.x509CAService.CreateCertificate(&casapi.CreateCertificateRequest{ Template: leaf, CSR: csr, Lifetime: lifetime, Backdate: signOpts.Backdate, }) if err != nil { return nil, errs.Wrap(http.StatusInternalServerError, err, "authority.Sign; error creating certificate", opts...) } fullchain := append([]*x509.Certificate{resp.Certificate}, resp.CertificateChain...) if err = a.storeCertificate(fullchain); err != nil { if err != db.ErrNotImplemented { return nil, errs.Wrap(http.StatusInternalServerError, err, "authority.Sign; error storing certificate in db", opts...) } } return fullchain, nil } // Renew creates a new Certificate identical to the old certificate, except // with a validity window that begins 'now'. func (a *Authority) Renew(oldCert *x509.Certificate) ([]*x509.Certificate, error) { return a.Rekey(oldCert, nil) } // Rekey is used for rekeying and renewing based on the public key. // If the public key is 'nil' then it's assumed that the cert should be renewed // using the existing public key. If the public key is not 'nil' then it's // assumed that the cert should be rekeyed. // For both Rekey and Renew all other attributes of the new certificate should // match the old certificate. The exceptions are 'AuthorityKeyId' (which may // have changed), 'SubjectKeyId' (different in case of rekey), and // 'NotBefore/NotAfter' (the validity duration of the new certificate should be // equal to the old one, but starting 'now'). func (a *Authority) Rekey(oldCert *x509.Certificate, pk crypto.PublicKey) ([]*x509.Certificate, error) { isRekey := (pk != nil) opts := []interface{}{errs.WithKeyVal("serialNumber", oldCert.SerialNumber.String())} // Check step provisioner extensions if err := a.authorizeRenew(oldCert); err != nil { return nil, errs.Wrap(http.StatusInternalServerError, err, "authority.Rekey", opts...) } // Durations backdate := a.config.AuthorityConfig.Backdate.Duration duration := oldCert.NotAfter.Sub(oldCert.NotBefore) lifetime := duration - backdate // Create new certificate from previous values. // Issuer, NotBefore, NotAfter and SubjectKeyId will be set by the CAS. newCert := &x509.Certificate{ Subject: oldCert.Subject, KeyUsage: oldCert.KeyUsage, UnhandledCriticalExtensions: oldCert.UnhandledCriticalExtensions, ExtKeyUsage: oldCert.ExtKeyUsage, UnknownExtKeyUsage: oldCert.UnknownExtKeyUsage, BasicConstraintsValid: oldCert.BasicConstraintsValid, IsCA: oldCert.IsCA, MaxPathLen: oldCert.MaxPathLen, MaxPathLenZero: oldCert.MaxPathLenZero, OCSPServer: oldCert.OCSPServer, IssuingCertificateURL: oldCert.IssuingCertificateURL, PermittedDNSDomainsCritical: oldCert.PermittedDNSDomainsCritical, PermittedEmailAddresses: oldCert.PermittedEmailAddresses, DNSNames: oldCert.DNSNames, EmailAddresses: oldCert.EmailAddresses, IPAddresses: oldCert.IPAddresses, URIs: oldCert.URIs, PermittedDNSDomains: oldCert.PermittedDNSDomains, ExcludedDNSDomains: oldCert.ExcludedDNSDomains, PermittedIPRanges: oldCert.PermittedIPRanges, ExcludedIPRanges: oldCert.ExcludedIPRanges, ExcludedEmailAddresses: oldCert.ExcludedEmailAddresses, PermittedURIDomains: oldCert.PermittedURIDomains, ExcludedURIDomains: oldCert.ExcludedURIDomains, CRLDistributionPoints: oldCert.CRLDistributionPoints, PolicyIdentifiers: oldCert.PolicyIdentifiers, } if isRekey { newCert.PublicKey = pk } else { newCert.PublicKey = oldCert.PublicKey } // Copy all extensions except: // // 1. Authority Key Identifier - This one might be different if we rotate // the intermediate certificate and it will cause a TLS bad certificate // error. // // 2. Subject Key Identifier, if rekey - For rekey, SubjectKeyIdentifier // extension will be calculated for the new public key by // x509util.CreateCertificate() for _, ext := range oldCert.Extensions { if ext.Id.Equal(oidAuthorityKeyIdentifier) { continue } if ext.Id.Equal(oidSubjectKeyIdentifier) && isRekey { newCert.SubjectKeyId = nil continue } newCert.ExtraExtensions = append(newCert.ExtraExtensions, ext) } resp, err := a.x509CAService.RenewCertificate(&casapi.RenewCertificateRequest{ Template: newCert, Lifetime: lifetime, Backdate: backdate, }) if err != nil { return nil, errs.Wrap(http.StatusInternalServerError, err, "authority.Rekey", opts...) } fullchain := append([]*x509.Certificate{resp.Certificate}, resp.CertificateChain...) if err = a.storeRenewedCertificate(oldCert, fullchain); err != nil { if err != db.ErrNotImplemented { return nil, errs.Wrap(http.StatusInternalServerError, err, "authority.Rekey; error storing certificate in db", opts...) } } return fullchain, nil } // storeCertificate allows to use an extension of the db.AuthDB interface that // can log the full chain of certificates. // // TODO: at some point we should replace the db.AuthDB interface to implement // `StoreCertificate(...*x509.Certificate) error` instead of just // `StoreCertificate(*x509.Certificate) error`. func (a *Authority) storeCertificate(fullchain []*x509.Certificate) error { type certificateChainStorer interface { StoreCertificateChain(...*x509.Certificate) error } // Store certificate in linkedca if s, ok := a.adminDB.(certificateChainStorer); ok { return s.StoreCertificateChain(fullchain...) } // Store certificate in local db if s, ok := a.db.(certificateChainStorer); ok { return s.StoreCertificateChain(fullchain...) } return a.db.StoreCertificate(fullchain[0]) } // storeRenewedCertificate allows to use an extension of the db.AuthDB interface // that can log if a certificate has been renewed or rekeyed. // // TODO: at some point we should implement this in the standard implementation. func (a *Authority) storeRenewedCertificate(oldCert *x509.Certificate, fullchain []*x509.Certificate) error { type renewedCertificateChainStorer interface { StoreRenewedCertificate(*x509.Certificate, ...*x509.Certificate) error } // Store certificate in linkedca if s, ok := a.adminDB.(renewedCertificateChainStorer); ok { return s.StoreRenewedCertificate(oldCert, fullchain...) } // Store certificate in local db if s, ok := a.db.(renewedCertificateChainStorer); ok { return s.StoreRenewedCertificate(oldCert, fullchain...) } return a.db.StoreCertificate(fullchain[0]) } // RevokeOptions are the options for the Revoke API. type RevokeOptions struct { Serial string Reason string ReasonCode int PassiveOnly bool MTLS bool ACME bool Crt *x509.Certificate OTT string } // Revoke revokes a certificate. // // NOTE: Only supports passive revocation - prevent existing certificates from // being renewed. // // TODO: Add OCSP and CRL support. func (a *Authority) Revoke(ctx context.Context, revokeOpts *RevokeOptions) error { opts := []interface{}{ errs.WithKeyVal("serialNumber", revokeOpts.Serial), errs.WithKeyVal("reasonCode", revokeOpts.ReasonCode), errs.WithKeyVal("reason", revokeOpts.Reason), errs.WithKeyVal("passiveOnly", revokeOpts.PassiveOnly), errs.WithKeyVal("MTLS", revokeOpts.MTLS), errs.WithKeyVal("ACME", revokeOpts.ACME), errs.WithKeyVal("context", provisioner.MethodFromContext(ctx).String()), } if revokeOpts.MTLS || revokeOpts.ACME { opts = append(opts, errs.WithKeyVal("certificate", base64.StdEncoding.EncodeToString(revokeOpts.Crt.Raw))) } else { opts = append(opts, errs.WithKeyVal("token", revokeOpts.OTT)) } rci := &db.RevokedCertificateInfo{ Serial: revokeOpts.Serial, ReasonCode: revokeOpts.ReasonCode, Reason: revokeOpts.Reason, MTLS: revokeOpts.MTLS, ACME: revokeOpts.ACME, RevokedAt: time.Now().UTC(), } var ( p provisioner.Interface err error ) // If not mTLS nor ACME, then get the TokenID of the token. if !(revokeOpts.MTLS || revokeOpts.ACME) { token, err := jose.ParseSigned(revokeOpts.OTT) if err != nil { return errs.Wrap(http.StatusUnauthorized, err, "authority.Revoke; error parsing token", opts...) } // Get claims w/out verification. var claims Claims if err = token.UnsafeClaimsWithoutVerification(&claims); err != nil { return errs.Wrap(http.StatusUnauthorized, err, "authority.Revoke", opts...) } // This method will also validate the audiences for JWK provisioners. p, err = a.LoadProvisionerByToken(token, &claims.Claims) if err != nil { return err } rci.ProvisionerID = p.GetID() rci.TokenID, err = p.GetTokenID(revokeOpts.OTT) if err != nil && !errors.Is(err, provisioner.ErrAllowTokenReuse) { return errs.Wrap(http.StatusInternalServerError, err, "authority.Revoke; could not get ID for token") } opts = append(opts, errs.WithKeyVal("provisionerID", rci.ProvisionerID), errs.WithKeyVal("tokenID", rci.TokenID), ) } else if p, err = a.LoadProvisionerByCertificate(revokeOpts.Crt); err == nil { // Load the Certificate provisioner if one exists. rci.ProvisionerID = p.GetID() opts = append(opts, errs.WithKeyVal("provisionerID", rci.ProvisionerID)) } if provisioner.MethodFromContext(ctx) == provisioner.SSHRevokeMethod { err = a.revokeSSH(nil, rci) } else { // Revoke an X.509 certificate using CAS. If the certificate is not // provided we will try to read it from the db. If the read fails we // won't throw an error as it will be responsibility of the CAS // implementation to require a certificate. var revokedCert *x509.Certificate if revokeOpts.Crt != nil { revokedCert = revokeOpts.Crt } else if rci.Serial != "" { revokedCert, _ = a.db.GetCertificate(rci.Serial) } // CAS operation, note that SoftCAS (default) is a noop. // The revoke happens when this is stored in the db. _, err = a.x509CAService.RevokeCertificate(&casapi.RevokeCertificateRequest{ Certificate: revokedCert, SerialNumber: rci.Serial, Reason: rci.Reason, ReasonCode: rci.ReasonCode, PassiveOnly: revokeOpts.PassiveOnly, }) if err != nil { return errs.Wrap(http.StatusInternalServerError, err, "authority.Revoke", opts...) } // Save as revoked in the Db. err = a.revoke(revokedCert, rci) } switch err { case nil: return nil case db.ErrNotImplemented: return errs.NotImplemented("authority.Revoke; no persistence layer configured", opts...) case db.ErrAlreadyExists: return errs.ApplyOptions( errs.BadRequest("certificate with serial number '%s' is already revoked", rci.Serial), opts..., ) default: return errs.Wrap(http.StatusInternalServerError, err, "authority.Revoke", opts...) } } func (a *Authority) revoke(crt *x509.Certificate, rci *db.RevokedCertificateInfo) error { if lca, ok := a.adminDB.(interface { Revoke(*x509.Certificate, *db.RevokedCertificateInfo) error }); ok { return lca.Revoke(crt, rci) } return a.db.Revoke(rci) } func (a *Authority) revokeSSH(crt *ssh.Certificate, rci *db.RevokedCertificateInfo) error { if lca, ok := a.adminDB.(interface { RevokeSSH(*ssh.Certificate, *db.RevokedCertificateInfo) error }); ok { return lca.RevokeSSH(crt, rci) } return a.db.Revoke(rci) } // GetTLSCertificate creates a new leaf certificate to be used by the CA HTTPS server. func (a *Authority) GetTLSCertificate() (*tls.Certificate, error) { fatal := func(err error) (*tls.Certificate, error) { return nil, errs.Wrap(http.StatusInternalServerError, err, "authority.GetTLSCertificate") } // Generate default key. priv, err := keyutil.GenerateDefaultKey() if err != nil { return fatal(err) } signer, ok := priv.(crypto.Signer) if !ok { return fatal(errors.New("private key is not a crypto.Signer")) } // Create initial certificate request. cr, err := x509util.CreateCertificateRequest("Step Online CA", a.config.DNSNames, signer) if err != nil { return fatal(err) } // Generate certificate template directly from the certificate request. template, err := x509util.NewCertificate(cr) if err != nil { return fatal(err) } // Get x509 certificate template, set validity and sign it. now := time.Now() certTpl := template.GetCertificate() certTpl.NotBefore = now.Add(-1 * time.Minute) certTpl.NotAfter = now.Add(24 * time.Hour) resp, err := a.x509CAService.CreateCertificate(&casapi.CreateCertificateRequest{ Template: certTpl, CSR: cr, Lifetime: 24 * time.Hour, Backdate: 1 * time.Minute, }) if err != nil { return fatal(err) } // Generate PEM blocks to create tls.Certificate pemBlocks := pem.EncodeToMemory(&pem.Block{ Type: "CERTIFICATE", Bytes: resp.Certificate.Raw, }) for _, crt := range resp.CertificateChain { pemBlocks = append(pemBlocks, pem.EncodeToMemory(&pem.Block{ Type: "CERTIFICATE", Bytes: crt.Raw, })...) } keyPEM, err := pemutil.Serialize(priv) if err != nil { return fatal(err) } tlsCrt, err := tls.X509KeyPair(pemBlocks, pem.EncodeToMemory(keyPEM)) if err != nil { return fatal(err) } // Set leaf certificate tlsCrt.Leaf = resp.Certificate return &tlsCrt, nil } // templatingError tries to extract more information about the cause of // an error related to (most probably) malformed template data and adds // this to the error message. func templatingError(err error) error { cause := errors.Cause(err) var ( syntaxError *json.SyntaxError typeError *json.UnmarshalTypeError ) if errors.As(err, &syntaxError) { // offset is arguably not super clear to the user, but it's the best we can do here cause = fmt.Errorf("%s at offset %d", cause.Error(), syntaxError.Offset) } else if errors.As(err, &typeError) { // slightly rewriting the default error message to include the offset cause = fmt.Errorf("cannot unmarshal %s at offset %d into Go value of type %s", typeError.Value, typeError.Offset, typeError.Type) } return errors.Wrap(cause, "error applying certificate template") }