// NewBundler creates a new Bundler from the files passed in; these
// files should contain a list of valid root certificates and a list
// of valid intermediate certificates, respectively.
func NewBundler(caBundleFile, intBundleFile string) (*Bundler, error) {
	log.Debug("Loading CA bundle: ", caBundleFile)
	caBundlePEM, err := ioutil.ReadFile(caBundleFile)
	if err != nil {
		log.Errorf("root bundle failed to load: %v", err)
		return nil, errors.Wrap(errors.RootError, errors.ReadFailed, err)
	}

	log.Debug("Loading Intermediate bundle: ", intBundleFile)
	intBundlePEM, err := ioutil.ReadFile(intBundleFile)
	if err != nil {
		log.Errorf("intermediate bundle failed to load: %v", err)
		return nil, errors.Wrap(errors.IntermediatesError, errors.ReadFailed, err)
	}

	if _, err := os.Stat(IntermediateStash); err != nil && os.IsNotExist(err) {
		log.Infof("intermediate stash directory %s doesn't exist, creating", IntermediateStash)
		err = os.MkdirAll(IntermediateStash, 0755)
		if err != nil {
			log.Errorf("failed to create intermediate stash directory %s: %v",
				IntermediateStash, err)
			return nil, err
		}
		log.Infof("intermediate stash directory %s created", IntermediateStash)
	}
	return NewBundlerFromPEM(caBundlePEM, intBundlePEM)
}

// LoadPlatforms reads the file content as a json object array and convert it
// to Platforms.
func LoadPlatforms(filename string) error {
	relativePath := filepath.Dir(filename)
	// Attempt to load root certificate metadata
	log.Debug("Loading platform metadata: ", filename)
	bytes, err := ioutil.ReadFile(filename)
	if err != nil {
		return fmt.Errorf("platform metadata failed to load: %v", err)
	}
	var rawPlatforms []Platform
	if bytes != nil {
		err = json.Unmarshal(bytes, &rawPlatforms)
		if err != nil {
			return fmt.Errorf("platform metadata failed to parse: %v", err)
		}
	}

	for _, platform := range rawPlatforms {
		if platform.KeyStoreFile != "" {
			platform.KeyStoreFile = path.Join(relativePath, platform.KeyStoreFile)
		}
		ok := platform.ParseAndLoad()
		if !ok {
			// erase all loaded platforms
			Platforms = nil
			return fmt.Errorf("fail to finalize the parsing of platform metadata: %v", platform)
		}

		log.Infof("Platform metadata is loaded: %v %v", platform.Name, len(platform.KeyStore))
		Platforms = append(Platforms, platform)
	}

	return nil
}

// SignerFromConfig takes the Config and creates the appropriate
// signer.Signer object
func SignerFromConfig(c cli.Config) (signer.Signer, error) {
	// If there is a config, use its signing policy. Otherwise create a default policy.
	var policy *config.Signing
	if c.CFG != nil {
		policy = c.CFG.Signing
	} else {
		policy = &config.Signing{
			Profiles: map[string]*config.SigningProfile{},
			Default:  config.DefaultConfig(),
		}
	}

	// Make sure the policy reflects the new remote
	if c.Remote != "" {
		err := policy.OverrideRemotes(c.Remote)
		if err != nil {
			log.Infof("Invalid remote %v, reverting to configuration default", c.Remote)
			return nil, err
		}
	}

	s, err := universal.NewSigner(cli.RootFromConfig(&c), policy)
	if err != nil {
		return nil, err
	}

	return s, nil
}

// NewSourceFromFile reads the named file into an InMemorySource.
// The file read by this function must contain whitespace-separated OCSP
// responses. Each OCSP response must be in base64-encoded DER form (i.e.,
// PEM without headers or whitespace).  Invalid responses are ignored.
// This function pulls the entire file into an InMemorySource.
func NewSourceFromFile(responseFile string) (Source, error) {
	fileContents, err := ioutil.ReadFile(responseFile)
	if err != nil {
		return nil, err
	}

	responsesB64 := regexp.MustCompile("\\s").Split(string(fileContents), -1)
	src := InMemorySource{}
	for _, b64 := range responsesB64 {
		der, tmpErr := base64.StdEncoding.DecodeString(b64)
		if tmpErr != nil {
			log.Errorf("Base64 decode error on: %s", b64)
			continue
		}

		response, tmpErr := ocsp.ParseResponse(der, nil)
		if tmpErr != nil {
			log.Errorf("OCSP decode error on: %s", b64)
			continue
		}

		src[response.SerialNumber.String()] = der
	}

	log.Infof("Read %d OCSP responses", len(src))
	return src, nil
}

// Scan performs the scan to be performed on the given host and stores its result.
func (s *Scanner) Scan(host string) (Grade, Output, error) {
	grade, output, err := s.scan(host)
	if err != nil {
		log.Infof("scan: %v", err)
		return grade, output, err
	}
	return grade, output, err
}

// A Responder can process both GET and POST requests.  The mapping
// from an OCSP request to an OCSP response is done by the Source;
// the Responder simply decodes the request, and passes back whatever
// response is provided by the source.
func (rs Responder) ServeHTTP(response http.ResponseWriter, request *http.Request) {
	// Read response from request
	var requestBody []byte
	var err error
	switch request.Method {
	case "GET":
		re := regexp.MustCompile("^.*/")
		base64Request := re.ReplaceAllString(request.RequestURI, "")
		base64Request, err = url.QueryUnescape(base64Request)
		if err != nil {
			return
		}
		requestBody, err = base64.StdEncoding.DecodeString(base64Request)
		if err != nil {
			return
		}
	case "POST":
		requestBody, err = ioutil.ReadAll(request.Body)
		if err != nil {
			response.WriteHeader(http.StatusBadRequest)
			return
		}
	default:
		response.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	// TODO log request
	b64Body := base64.StdEncoding.EncodeToString(requestBody)
	log.Infof("Received OCSP request: %s", b64Body)

	// All responses after this point will be OCSP.
	// We could check for the content type of the request, but that
	// seems unnecessariliy restrictive.
	response.Header().Add("Content-Type", "application/ocsp-response")

	// Parse response as an OCSP request
	// XXX: This fails if the request contains the nonce extension.
	//      We don't intend to support nonces anyway, but maybe we
	//      should return unauthorizedRequest instead of malformed.
	ocspRequest, err := ocsp.ParseRequest(requestBody)
	if err != nil {
		log.Errorf("Error decoding request body: %s", b64Body)
		response.Write(malformedRequestErrorResponse)
		return
	}

	// Look up OCSP response from source
	ocspResponse, found := rs.Source.Response(ocspRequest)
	if !found {
		log.Errorf("No response found for request: %s", b64Body)
		response.Write(unauthorizedErrorResponse)
		return
	}

	// Write OCSP response to response
	response.WriteHeader(http.StatusOK)
	response.Write(ocspResponse)
}

// Handle implements an http.Handler interface for the bundle handler.
func (h *Handler) Handle(w http.ResponseWriter, r *http.Request) error {
	blob, matched, err := api.ProcessRequestFirstMatchOf(r,
		[][]string{
			[]string{"certificate"},
			[]string{"domain"},
		})
	if err != nil {
		log.Warningf("invalid request: %v", err)
		return err
	}

	flavor := blob["flavor"]
	bf := bundler.Ubiquitous
	if flavor != "" {
		bf = bundler.BundleFlavor(flavor)
	}
	log.Infof("request for flavor %v", bf)

	var result *bundler.Bundle
	switch matched[0] {
	case "domain":
		bundle, err := h.bundler.BundleFromRemote(blob["domain"], blob["ip"], bf)
		if err != nil {
			log.Warningf("couldn't bundle from remote: %v", err)
			return err
		}
		result = bundle
	case "certificate":
		bundle, err := h.bundler.BundleFromPEM([]byte(blob["certificate"]), []byte(blob["private_key"]), bf)
		if err != nil {
			log.Warning("bad PEM certifcate or private key")
			return err
		}

		serverName := blob["domain"]
		ip := blob["ip"]

		if serverName != "" {
			err := bundle.Cert.VerifyHostname(serverName)
			if err != nil {
				return errors.Wrap(errors.CertificateError, errors.VerifyFailed, err)
			}

		}

		if ip != "" {
			err := bundle.Cert.VerifyHostname(ip)
			if err != nil {
				return errors.Wrap(errors.CertificateError, errors.VerifyFailed, err)
			}
		}

		result = bundle
	}
	log.Info("wrote response")
	return api.SendResponse(w, result)
}

// ServeHTTP encapsulates the call to underlying Handler to handle the request
// and return the response with proper HTTP status code
func (h HTTPHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	var err error
	// Throw 405 when requested with an unsupported verb.
	if r.Method != h.Method {
		err = errors.NewMethodNotAllowed(r.Method)
	} else {
		err = h.Handle(w, r)
	}
	status := handleError(w, err)
	log.Infof("%s - \"%s %s\" %d", r.RemoteAddr, r.Method, r.URL, status)
}

// Handle accepts client information requests, and uses the label to
// look up the signer whose public certificate should be retrieved. If
// the label is empty, the default label is used.
func (h *MultiHandler) Handle(w http.ResponseWriter, r *http.Request) error {
	req := new(client.InfoReq)
	body, err := ioutil.ReadAll(r.Body)
	if err != nil {
		log.Warningf("failed to read request body: %v", err)
		return errors.NewBadRequest(err)
	}
	err = json.Unmarshal(body, req)
	if err != nil {
		log.Warningf("failed to unmarshal request: %v", err)
		return errors.NewBadRequest(err)
	}

	log.Debug("checking label")
	if req.Label == "" {
		req.Label = h.defaultLabel
	}

	if _, ok := h.signers[req.Label]; !ok {
		log.Warningf("request for invalid endpoint")
		return errors.NewBadRequestString("bad label")
	}

	log.Debug("getting cert")
	cert, err := h.signers[req.Label].Certificate("", req.Profile)
	if err != nil {
		log.Infof("error getting certificate: %v", err)
		return err
	}

	resp := client.InfoResp{
		Certificate: bundler.PemBlockToString(&pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw}),
	}

	response := api.NewSuccessResponse(resp)
	w.Header().Set("Content-Type", "application/json")
	enc := json.NewEncoder(w)
	return enc.Encode(response)
}

func (s *Signer) sign(template *x509.Certificate, profile *config.SigningProfile) (cert []byte, err error) {
	err = signer.FillTemplate(template, s.policy.Default, profile)
	if err != nil {
		return
	}

	var initRoot bool
	if s.ca == nil {
		if !template.IsCA {
			err = cferr.New(cferr.PolicyError, cferr.InvalidRequest)
			return
		}
		template.DNSNames = nil
		template.EmailAddresses = nil
		s.ca = template
		initRoot = true
		template.MaxPathLen = signer.MaxPathLen
	} else if template.IsCA {
		template.MaxPathLen = 1
		template.DNSNames = nil
		template.EmailAddresses = nil
	}

	derBytes, err := x509.CreateCertificate(rand.Reader, template, s.ca, template.PublicKey, s.priv)
	if err != nil {
		return nil, cferr.Wrap(cferr.CertificateError, cferr.Unknown, err)
	}
	if initRoot {
		s.ca, err = x509.ParseCertificate(derBytes)
		if err != nil {
			return nil, cferr.Wrap(cferr.CertificateError, cferr.ParseFailed, err)
		}
	}

	cert = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
	log.Infof("signed certificate with serial number %d", template.SerialNumber)
	return
}

// ParseRequest takes a certificate request and generates a key and
// CSR from it. It does no validation -- caveat emptor. It will,
// however, fail if the key request is not valid (i.e., an unsupported
// curve or RSA key size). The lack of validation was specifically
// chosen to allow the end user to define a policy and validate the
// request appropriately before calling this function.
func ParseRequest(req *CertificateRequest) (csr, key []byte, err error) {
	log.Info("received CSR")
	if req.KeyRequest == nil {
		req.KeyRequest = &KeyRequest{
			Algo: DefaultKeyRequest.Algo,
			Size: DefaultKeyRequest.Size,
		}
	}

	log.Infof("generating key: %s-%d", req.KeyRequest.Algo, req.KeyRequest.Size)
	priv, err := req.KeyRequest.Generate()
	if err != nil {
		err = cferr.Wrap(cferr.PrivateKeyError, cferr.GenerationFailed, err)
		return
	}

	switch priv := priv.(type) {
	case *rsa.PrivateKey:
		key = x509.MarshalPKCS1PrivateKey(priv)
		block := pem.Block{
			Type:  "RSA PRIVATE KEY",
			Bytes: key,
		}
		key = pem.EncodeToMemory(&block)
	case *ecdsa.PrivateKey:
		key, err = x509.MarshalECPrivateKey(priv)
		if err != nil {
			err = cferr.Wrap(cferr.PrivateKeyError, cferr.Unknown, err)
			return
		}
		block := pem.Block{
			Type:  "EC PRIVATE KEY",
			Bytes: key,
		}
		key = pem.EncodeToMemory(&block)
	default:
		panic("Generate should have failed to produce a valid key.")
	}

	var tpl = x509.CertificateRequest{
		Subject:            req.Name(),
		SignatureAlgorithm: req.KeyRequest.SigAlgo(),
		DNSNames:           req.Hosts,
	}
	csr, err = x509.CreateCertificateRequest(rand.Reader, &tpl, priv)
	if err != nil {
		log.Errorf("failed to generate a CSR: %v", err)
		// The use of CertificateError was a matter of some
		// debate; it is the one edge case in which a new
		// error category specifically for CSRs might be
		// useful, but it was deemed that one edge case did
		// not a new category justify.
		err = cferr.Wrap(cferr.CertificateError, cferr.BadRequest, err)
		return
	}
	block := pem.Block{
		Type:  "CERTIFICATE REQUEST",
		Bytes: csr,
	}

	log.Info("encoded CSR")
	csr = pem.EncodeToMemory(&block)
	return
}

//.........这里部分代码省略.........
		if profile.CSRWhitelist.IPAddresses {
			safeTemplate.IPAddresses = csrTemplate.IPAddresses
		}
	}

	OverrideHosts(&safeTemplate, req.Hosts)
	safeTemplate.Subject = PopulateSubjectFromCSR(req.Subject, safeTemplate.Subject)

	// If there is a whitelist, ensure that both the Common Name and SAN DNSNames match
	if profile.NameWhitelist != nil {
		if safeTemplate.Subject.CommonName != "" {
			if profile.NameWhitelist.Find([]byte(safeTemplate.Subject.CommonName)) == nil {
				return nil, cferr.New(cferr.PolicyError, cferr.InvalidPolicy)
			}
		}
		for _, name := range safeTemplate.DNSNames {
			if profile.NameWhitelist.Find([]byte(name)) == nil {
				return nil, cferr.New(cferr.PolicyError, cferr.InvalidPolicy)
			}
		}
	}

	if profile.ClientProvidesSerialNumbers {
		if req.Serial == nil {
			fmt.Printf("xx %#v\n", profile)
			return nil, cferr.New(cferr.CertificateError, cferr.MissingSerial)
		}
		safeTemplate.SerialNumber = req.Serial
	} else {
		serialNumber, err := rand.Int(rand.Reader, new(big.Int).SetInt64(math.MaxInt64))
		if err != nil {
			return nil, cferr.Wrap(cferr.CertificateError, cferr.Unknown, err)
		}
		safeTemplate.SerialNumber = serialNumber
	}

	if len(req.Extensions) > 0 {
		for _, ext := range req.Extensions {
			oid := asn1.ObjectIdentifier(ext.ID)
			if !profile.ExtensionWhitelist[oid.String()] {
				return nil, cferr.New(cferr.CertificateError, cferr.InvalidRequest)
			}

			rawValue, err := hex.DecodeString(ext.Value)
			if err != nil {
				return nil, cferr.Wrap(cferr.CertificateError, cferr.InvalidRequest, err)
			}

			safeTemplate.ExtraExtensions = append(safeTemplate.ExtraExtensions, pkix.Extension{
				Id:       oid,
				Critical: ext.Critical,
				Value:    rawValue,
			})
		}
	}

	var certTBS = safeTemplate

	if len(profile.CTLogServers) > 0 {
		// Add a poison extension which prevents validation
		var poisonExtension = pkix.Extension{Id: signer.CTPoisonOID, Critical: true, Value: []byte{0x05, 0x00}}
		var poisonedPreCert = certTBS
		poisonedPreCert.ExtraExtensions = append(safeTemplate.ExtraExtensions, poisonExtension)
		cert, err = s.sign(&poisonedPreCert, profile)
		if err != nil {
			return
		}

		derCert, _ := pem.Decode(cert)
		prechain := []ct.ASN1Cert{derCert.Bytes, s.ca.Raw}
		var sctList []ct.SignedCertificateTimestamp

		for _, server := range profile.CTLogServers {
			log.Infof("submitting poisoned precertificate to %s", server)
			var ctclient = client.New(server)
			var resp *ct.SignedCertificateTimestamp
			resp, err = ctclient.AddPreChain(prechain)
			if err != nil {
				return nil, cferr.Wrap(cferr.CTError, cferr.PrecertSubmissionFailed, err)
			}
			sctList = append(sctList, *resp)
		}

		var serializedSCTList []byte
		serializedSCTList, err = serializeSCTList(sctList)
		if err != nil {
			return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
		}

		// Serialize again as an octet string before embedding
		serializedSCTList, err = asn1.Marshal(serializedSCTList)
		if err != nil {
			return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
		}

		var SCTListExtension = pkix.Extension{Id: signer.SCTListOID, Critical: false, Value: serializedSCTList}
		certTBS.ExtraExtensions = append(certTBS.ExtraExtensions, SCTListExtension)
	}
	return s.sign(&certTBS, profile)
}

// ParseRequest takes a certificate request and generates a key and
// CSR from it. It does no validation -- caveat emptor. It will,
// however, fail if the key request is not valid (i.e., an unsupported
// curve or RSA key size). The lack of validation was specifically
// chosen to allow the end user to define a policy and validate the
// request appropriately before calling this function.
func ParseRequest(req *CertificateRequest) (csr, key []byte, err error) {
	log.Info("received CSR")
	if req.KeyRequest == nil {
		req.KeyRequest = &KeyRequest{
			Algo: DefaultKeyRequest.Algo,
			Size: DefaultKeyRequest.Size,
		}
	}

	log.Infof("generating key: %s-%d", req.KeyRequest.Algo, req.KeyRequest.Size)
	priv, err := req.KeyRequest.Generate()
	if err != nil {
		err = cferr.Wrap(cferr.PrivateKeyError, cferr.GenerationFailed, err)
		return
	}

	switch priv := priv.(type) {
	case *rsa.PrivateKey:
		key = x509.MarshalPKCS1PrivateKey(priv)
		block := pem.Block{
			Type:  "RSA PRIVATE KEY",
			Bytes: key,
		}
		key = pem.EncodeToMemory(&block)
	case *ecdsa.PrivateKey:
		key, err = x509.MarshalECPrivateKey(priv)
		if err != nil {
			err = cferr.Wrap(cferr.PrivateKeyError, cferr.Unknown, err)
			return
		}
		block := pem.Block{
			Type:  "EC PRIVATE KEY",
			Bytes: key,
		}
		key = pem.EncodeToMemory(&block)
	default:
		panic("Generate should have failed to produce a valid key.")
	}

	var tpl = x509.CertificateRequest{
		Subject:            req.Name(),
		SignatureAlgorithm: req.KeyRequest.SigAlgo(),
	}

	for i := range req.Hosts {
		if ip := net.ParseIP(req.Hosts[i]); ip != nil {
			tpl.IPAddresses = append(tpl.IPAddresses, ip)
		} else {
			tpl.DNSNames = append(tpl.DNSNames, req.Hosts[i])
		}
	}

	csr, err = x509.CreateCertificateRequest(rand.Reader, &tpl, priv)
	if err != nil {
		log.Errorf("failed to generate a CSR: %v", err)
		err = cferr.Wrap(cferr.CSRError, cferr.BadRequest, err)
		return
	}
	block := pem.Block{
		Type:  "CERTIFICATE REQUEST",
		Bytes: csr,
	}

	log.Info("encoded CSR")
	csr = pem.EncodeToMemory(&block)
	return
}

func gencertMain(args []string, c cli.Config) (err error) {

	csrJSONFile, args, err := cli.PopFirstArgument(args)
	if err != nil {
		return
	}

	csrJSONFileBytes, err := cli.ReadStdin(csrJSONFile)
	if err != nil {
		return
	}

	var req csr.CertificateRequest
	err = json.Unmarshal(csrJSONFileBytes, &req)
	if err != nil {
		return
	}

	if c.IsCA {
		var key, cert []byte
		cert, err = initca.NewFromPEM(&req, c.CAKeyFile)
		if err != nil {
			log.Errorf("%v\n", err)
			log.Infof("generating a new CA key and certificate from CSR")
			cert, key, err = initca.New(&req)
			if err != nil {
				return
			}

		}
		cli.PrintCert(key, nil, cert)

	} else {
		if req.CA != nil {
			err = errors.New("ca section only permitted in initca")
			return
		}

		// Remote can be forced on the command line or in the config
		if c.Remote == "" && c.CFG == nil {
			if c.CAFile == "" {
				log.Error("need a CA certificate (provide one with -ca)")
				return
			}

			if c.CAKeyFile == "" {
				log.Error("need a CA key (provide one with -ca-key)")
				return
			}
		}

		var key, csrBytes []byte
		g := &csr.Generator{Validator: genkey.Validator}
		csrBytes, key, err = g.ProcessRequest(&req)
		if err != nil {
			key = nil
			return
		}

		s, err := sign.SignerFromConfig(c)
		if err != nil {
			return err
		}

		var cert []byte
		req := signer.SignRequest{
			Request: string(csrBytes),
			Hosts:   signer.SplitHosts(c.Hostname),
			Profile: c.Profile,
			Label:   c.Label,
		}

		cert, err = s.Sign(req)
		if err != nil {
			return err
		}

		cli.PrintCert(key, csrBytes, cert)
	}
	return nil
}

// Bundle takes an X509 certificate (already in the
// Certificate structure), a private key as crypto.Signer in one of the appropriate
// formats (i.e. *rsa.PrivateKey or *ecdsa.PrivateKey, or even a opaque key), using them to
// build a certificate bundle.
func (b *Bundler) Bundle(certs []*x509.Certificate, key crypto.Signer, flavor BundleFlavor) (*Bundle, error) {
	log.Infof("bundling certificate for %+v", certs[0].Subject)
	if len(certs) == 0 {
		return nil, nil
	}

	// Detect reverse ordering of the cert chain.
	if len(certs) > 1 && !partialVerify(certs) {
		rcerts := reverse(certs)
		if partialVerify(rcerts) {
			certs = rcerts
		}
	}

	var ok bool
	cert := certs[0]
	if key != nil {
		switch {
		case cert.PublicKeyAlgorithm == x509.RSA:

			var rsaPublicKey *rsa.PublicKey
			if rsaPublicKey, ok = key.Public().(*rsa.PublicKey); !ok {
				return nil, errors.New(errors.PrivateKeyError, errors.KeyMismatch)
			}
			if cert.PublicKey.(*rsa.PublicKey).N.Cmp(rsaPublicKey.N) != 0 {
				return nil, errors.New(errors.PrivateKeyError, errors.KeyMismatch)
			}
		case cert.PublicKeyAlgorithm == x509.ECDSA:
			var ecdsaPublicKey *ecdsa.PublicKey
			if ecdsaPublicKey, ok = key.Public().(*ecdsa.PublicKey); !ok {
				return nil, errors.New(errors.PrivateKeyError, errors.KeyMismatch)
			}
			if cert.PublicKey.(*ecdsa.PublicKey).X.Cmp(ecdsaPublicKey.X) != 0 {
				return nil, errors.New(errors.PrivateKeyError, errors.KeyMismatch)
			}
		default:
			return nil, errors.New(errors.PrivateKeyError, errors.NotRSAOrECC)
		}
	} else {
		switch {
		case cert.PublicKeyAlgorithm == x509.RSA:
		case cert.PublicKeyAlgorithm == x509.ECDSA:
		default:
			return nil, errors.New(errors.PrivateKeyError, errors.NotRSAOrECC)
		}
	}

	if cert.CheckSignatureFrom(cert) == nil {
		return nil, errors.New(errors.CertificateError, errors.SelfSigned)
	}

	bundle := new(Bundle)
	bundle.Cert = cert
	bundle.Key = key
	bundle.Issuer = &cert.Issuer
	bundle.Subject = &cert.Subject

	bundle.buildHostnames()

	// verify and store input intermediates to the intermediate pool.
	// Ignore the returned error here, will treat it in the second call.
	b.fetchIntermediates(certs)

	chains, err := cert.Verify(b.VerifyOptions())
	if err != nil {
		log.Debugf("verification failed: %v", err)
		// If the error was an unknown authority, try to fetch
		// the intermediate specified in the AIA and add it to
		// the intermediates bundle.
		switch err := err.(type) {
		case x509.UnknownAuthorityError:
			// Do nothing -- have the default case return out.
		default:
			return nil, errors.Wrap(errors.CertificateError, errors.VerifyFailed, err)
		}

		log.Debugf("searching for intermediates via AIA issuer")
		err = b.fetchIntermediates(certs)
		if err != nil {
			log.Debugf("search failed: %v", err)
			return nil, errors.Wrap(errors.CertificateError, errors.VerifyFailed, err)
		}

		log.Debugf("verifying new chain")
		chains, err = cert.Verify(b.VerifyOptions())
		if err != nil {
			log.Debugf("failed to verify chain: %v", err)
			return nil, errors.Wrap(errors.CertificateError, errors.VerifyFailed, err)
		}
		log.Debugf("verify ok")
	}
	var matchingChains [][]*x509.Certificate
	switch flavor {
	case Optimal:
		matchingChains = optimalChains(chains)
	case Ubiquitous:
//.........这里部分代码省略.........

// fetchIntermediates goes through each of the URLs in the AIA "Issuing
// CA" extensions and fetches those certificates. If those
// certificates are not present in either the root pool or
// intermediate pool, the certificate is saved to file and added to
// the list of intermediates to be used for verification. This will
// not add any new certificates to the root pool; if the ultimate
// issuer is not trusted, fetching the certicate here will not change
// that.
func (b *Bundler) fetchIntermediates(certs []*x509.Certificate) (err error) {
	log.Debugf("searching intermediates")
	if _, err := os.Stat(IntermediateStash); err != nil && os.IsNotExist(err) {
		log.Infof("intermediate stash directory %s doesn't exist, creating", IntermediateStash)
		err = os.MkdirAll(IntermediateStash, 0755)
		if err != nil {
			log.Errorf("failed to create intermediate stash directory %s: %v", IntermediateStash, err)
			return err
		}
		log.Infof("intermediate stash directory %s created", IntermediateStash)
	}

	// stores URLs and certificate signatures that have been seen
	seen := map[string]bool{}
	var foundChains int

	// Construct a verify chain as a reversed partial bundle,
	// such that the certs are ordered by promxity to the root CAs.
	var chain []*fetchedIntermediate
	for i, cert := range certs {
		var name string

		// Only construct filenames for non-leaf intermediate certs
		// so they will be saved to disk if necessary.
		// Leaf cert gets a empty name and will be skipped.
		if i > 0 {
			name = constructCertFileName(cert)
		}

		chain = append([]*fetchedIntermediate{&fetchedIntermediate{cert, name}}, chain...)
		seen[string(cert.Signature)] = true
	}

	// Verify the chain and store valid intermediates in the chain.
	// If it doesn't verify, fetch the intermediates and extend the chain
	// in a DFS manner and verify each time we hit a root.
	for {
		if len(chain) == 0 {
			log.Debugf("search complete")
			if foundChains == 0 {
				return x509.UnknownAuthorityError{}
			}
			return nil
		}

		current := chain[0]
		var advanced bool
		if b.verifyChain(chain) {
			foundChains++
		}
		log.Debugf("walk AIA issuers")
		for _, url := range current.Cert.IssuingCertificateURL {
			if seen[url] {
				log.Debugf("url %s has been seen", url)
				continue
			}
			crt, err := fetchRemoteCertificate(url)
			if err != nil {
				continue
			} else if seen[string(crt.Cert.Signature)] {
				log.Debugf("fetched certificate is known")
				continue
			}
			seen[url] = true
			seen[string(crt.Cert.Signature)] = true
			chain = append([]*fetchedIntermediate{crt}, chain...)
			advanced = true
			break
		}

		if !advanced {
			log.Debugf("didn't advance, stepping back")
			chain = chain[1:]
		}
	}
}

// A Responder can process both GET and POST requests.  The mapping
// from an OCSP request to an OCSP response is done by the Source;
// the Responder simply decodes the request, and passes back whatever
// response is provided by the source.
// Note: The caller must use http.StripPrefix to strip any path components
// (including '/') on GET requests.
// Do not use this responder in conjunction with http.NewServeMux, because the
// default handler will try to canonicalize path components by changing any
// strings of repeated '/' into a single '/', which will break the base64
// encoding.
func (rs Responder) ServeHTTP(response http.ResponseWriter, request *http.Request) {
	// Read response from request
	var requestBody []byte
	var err error
	switch request.Method {
	case "GET":
		base64Request, err := url.QueryUnescape(request.URL.Path)
		if err != nil {
			log.Errorf("Error decoding URL: %s", request.URL.Path)
			response.WriteHeader(http.StatusBadRequest)
			return
		}
		// url.QueryUnescape not only unescapes %2B escaping, but it additionally
		// turns the resulting '+' into a space, which makes base64 decoding fail.
		// So we go back afterwards and turn ' ' back into '+'. This means we
		// accept some malformed input that includes ' ' or %20, but that's fine.
		base64RequestBytes := []byte(base64Request)
		for i := range base64RequestBytes {
			if base64RequestBytes[i] == ' ' {
				base64RequestBytes[i] = '+'
			}
		}
		requestBody, err = base64.StdEncoding.DecodeString(string(base64RequestBytes))
		if err != nil {
			log.Errorf("Error decoding base64 from URL: %s", base64Request)
			response.WriteHeader(http.StatusBadRequest)
			return
		}
	case "POST":
		requestBody, err = ioutil.ReadAll(request.Body)
		if err != nil {
			log.Errorf("Problem reading body of POST: %s", err)
			response.WriteHeader(http.StatusBadRequest)
			return
		}
	default:
		response.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	// TODO log request
	b64Body := base64.StdEncoding.EncodeToString(requestBody)
	log.Infof("Received OCSP request: %s", b64Body)

	// All responses after this point will be OCSP.
	// We could check for the content type of the request, but that
	// seems unnecessariliy restrictive.
	response.Header().Add("Content-Type", "application/ocsp-response")

	// Parse response as an OCSP request
	// XXX: This fails if the request contains the nonce extension.
	//      We don't intend to support nonces anyway, but maybe we
	//      should return unauthorizedRequest instead of malformed.
	ocspRequest, err := ocsp.ParseRequest(requestBody)
	if err != nil {
		log.Errorf("Error decoding request body: %s", b64Body)
		response.WriteHeader(http.StatusBadRequest)
		response.Write(malformedRequestErrorResponse)
		return
	}

	// Look up OCSP response from source
	ocspResponse, found := rs.Source.Response(ocspRequest)
	if !found {
		log.Errorf("No response found for request: %s", b64Body)
		response.Write(unauthorizedErrorResponse)
		return
	}

	parsedResponse, err := ocsp.ParseResponse(ocspResponse, nil)
	if err != nil {
		log.Errorf("Error parsing response: %s", err)
		response.Write(unauthorizedErrorResponse)
		return
	}

	// Write OCSP response to response
	response.Header().Add("Last-Modified", parsedResponse.ProducedAt.Format(time.RFC1123))
	response.Header().Add("Expires", parsedResponse.NextUpdate.Format(time.RFC1123))
	maxAge := int64(parsedResponse.NextUpdate.Sub(rs.clk.Now()) / time.Second)
	if maxAge > 0 {
		response.Header().Add("Cache-Control", fmt.Sprintf("max-age=%d", maxAge))
	}
	response.WriteHeader(http.StatusOK)
	response.Write(ocspResponse)
}

//.........这里部分代码省略.........
		serialNumber := make([]byte, 20)
		_, err = io.ReadFull(rand.Reader, serialNumber)
		if err != nil {
			return nil, cferr.Wrap(cferr.CertificateError, cferr.Unknown, err)
		}

		// SetBytes interprets buf as the bytes of a big-endian
		// unsigned integer. The leading byte should be masked
		// off to ensure it isn't negative.
		serialNumber[0] &= 0x7F

		safeTemplate.SerialNumber = new(big.Int).SetBytes(serialNumber)
	}

	if len(req.Extensions) > 0 {
		for _, ext := range req.Extensions {
			oid := asn1.ObjectIdentifier(ext.ID)
			if !profile.ExtensionWhitelist[oid.String()] {
				return nil, cferr.New(cferr.CertificateError, cferr.InvalidRequest)
			}

			rawValue, err := hex.DecodeString(ext.Value)
			if err != nil {
				return nil, cferr.Wrap(cferr.CertificateError, cferr.InvalidRequest, err)
			}

			safeTemplate.ExtraExtensions = append(safeTemplate.ExtraExtensions, pkix.Extension{
				Id:       oid,
				Critical: ext.Critical,
				Value:    rawValue,
			})
		}
	}

	var certTBS = safeTemplate

	if len(profile.CTLogServers) > 0 {
		// Add a poison extension which prevents validation
		var poisonExtension = pkix.Extension{Id: signer.CTPoisonOID, Critical: true, Value: []byte{0x05, 0x00}}
		var poisonedPreCert = certTBS
		poisonedPreCert.ExtraExtensions = append(safeTemplate.ExtraExtensions, poisonExtension)
		cert, err = s.sign(&poisonedPreCert, profile)
		if err != nil {
			return
		}

		derCert, _ := pem.Decode(cert)
		prechain := []ct.ASN1Cert{derCert.Bytes, s.ca.Raw}
		var sctList []ct.SignedCertificateTimestamp

		for _, server := range profile.CTLogServers {
			log.Infof("submitting poisoned precertificate to %s", server)
			var ctclient = client.New(server)
			var resp *ct.SignedCertificateTimestamp
			resp, err = ctclient.AddPreChain(prechain)
			if err != nil {
				return nil, cferr.Wrap(cferr.CTError, cferr.PrecertSubmissionFailed, err)
			}
			sctList = append(sctList, *resp)
		}

		var serializedSCTList []byte
		serializedSCTList, err = serializeSCTList(sctList)
		if err != nil {
			return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
		}

		// Serialize again as an octet string before embedding
		serializedSCTList, err = asn1.Marshal(serializedSCTList)
		if err != nil {
			return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
		}

		var SCTListExtension = pkix.Extension{Id: signer.SCTListOID, Critical: false, Value: serializedSCTList}
		certTBS.ExtraExtensions = append(certTBS.ExtraExtensions, SCTListExtension)
	}
	var signedCert []byte
	signedCert, err = s.sign(&certTBS, profile)
	if err != nil {
		return nil, err
	}

	if s.dbAccessor != nil {
		var certRecord = &certdb.CertificateRecord{
			Serial:  certTBS.SerialNumber.String(),
			CALabel: req.Label,
			Status:  "good",
			Expiry:  certTBS.NotAfter,
			PEM:     string(signedCert),
		}

		err = s.dbAccessor.InsertCertificate(certRecord)
		if err != nil {
			return nil, err
		}
		log.Debug("saved certificate with serial number ", certTBS.SerialNumber)
	}

	return signedCert, nil
}