add lego libs pre-emptively (#357)

vendor/github.com/xenolf/lego/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015-2017 Sebastian Erhart
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/github.com/xenolf/lego/acmev2/challenges.go

@@ -0,0 +1,13 @@
+package acme
+
+// Challenge is a string that identifies a particular type and version of ACME challenge.
+type Challenge string
+
+const (
+	// HTTP01 is the "http-01" ACME challenge https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md#http
+	// Note: HTTP01ChallengePath returns the URL path to fulfill this challenge
+	HTTP01 = Challenge("http-01")
+	// DNS01 is the "dns-01" ACME challenge https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md#dns
+	// Note: DNS01Record returns a DNS record which will fulfill this challenge
+	DNS01 = Challenge("dns-01")
+)

vendor/github.com/xenolf/lego/acmev2/client.go

@@ -0,0 +1,813 @@
+// Package acme implements the ACME protocol for Let's Encrypt and other conforming providers.
+package acme
+
+import (
+	"crypto"
+	"crypto/x509"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var (
+	// Logger is an optional custom logger.
+	Logger *log.Logger
+)
+
+const (
+	// maxBodySize is the maximum size of body that we will read.
+	maxBodySize = 1024 * 1024
+
+	// overallRequestLimit is the overall number of request per second limited on the
+	// “new-reg”, “new-authz” and “new-cert” endpoints. From the documentation the
+	// limitation is 20 requests per second, but using 20 as value doesn't work but 18 do
+	overallRequestLimit = 18
+)
+
+// logf writes a log entry. It uses Logger if not
+// nil, otherwise it uses the default log.Logger.
+func logf(format string, args ...interface{}) {
+	if Logger != nil {
+		Logger.Printf(format, args...)
+	} else {
+		log.Printf(format, args...)
+	}
+}
+
+// User interface is to be implemented by users of this library.
+// It is used by the client type to get user specific information.
+type User interface {
+	GetEmail() string
+	GetRegistration() *RegistrationResource
+	GetPrivateKey() crypto.PrivateKey
+}
+
+// Interface for all challenge solvers to implement.
+type solver interface {
+	Solve(challenge challenge, domain string) error
+}
+
+type validateFunc func(j *jws, domain, uri string, chlng challenge) error
+
+// Client is the user-friendy way to ACME
+type Client struct {
+	directory directory
+	user      User
+	jws       *jws
+	keyType   KeyType
+	solvers   map[Challenge]solver
+}
+
+// NewClient creates a new ACME client on behalf of the user. The client will depend on
+// the ACME directory located at caDirURL for the rest of its actions.  A private
+// key of type keyType (see KeyType contants) will be generated when requesting a new
+// certificate if one isn't provided.
+func NewClient(caDirURL string, user User, keyType KeyType) (*Client, error) {
+	privKey := user.GetPrivateKey()
+	if privKey == nil {
+		return nil, errors.New("private key was nil")
+	}
+
+	var dir directory
+	if _, err := getJSON(caDirURL, &dir); err != nil {
+		return nil, fmt.Errorf("get directory at '%s': %v", caDirURL, err)
+	}
+
+	if dir.NewAccountURL == "" {
+		return nil, errors.New("directory missing new registration URL")
+	}
+	if dir.NewOrderURL == "" {
+		return nil, errors.New("directory missing new order URL")
+	}
+	/*if dir.RevokeCertURL == "" {
+		return nil, errors.New("directory missing revoke certificate URL")
+	}*/
+
+	jws := &jws{privKey: privKey, getNonceURL: dir.NewNonceURL}
+	if reg := user.GetRegistration(); reg != nil {
+		jws.kid = reg.URI
+	}
+
+	// REVIEW: best possibility?
+	// Add all available solvers with the right index as per ACME
+	// spec to this map. Otherwise they won`t be found.
+	solvers := make(map[Challenge]solver)
+	solvers[HTTP01] = &httpChallenge{jws: jws, validate: validate, provider: &HTTPProviderServer{}}
+
+	return &Client{directory: dir, user: user, jws: jws, keyType: keyType, solvers: solvers}, nil
+}
+
+// SetChallengeProvider specifies a custom provider p that can solve the given challenge type.
+func (c *Client) SetChallengeProvider(challenge Challenge, p ChallengeProvider) error {
+	switch challenge {
+	case HTTP01:
+		c.solvers[challenge] = &httpChallenge{jws: c.jws, validate: validate, provider: p}
+	case DNS01:
+		c.solvers[challenge] = &dnsChallenge{jws: c.jws, validate: validate, provider: p}
+	default:
+		return fmt.Errorf("Unknown challenge %v", challenge)
+	}
+	return nil
+}
+
+// SetHTTPAddress specifies a custom interface:port to be used for HTTP based challenges.
+// If this option is not used, the default port 80 and all interfaces will be used.
+// To only specify a port and no interface use the ":port" notation.
+//
+// NOTE: This REPLACES any custom HTTP provider previously set by calling
+// c.SetChallengeProvider with the default HTTP challenge provider.
+func (c *Client) SetHTTPAddress(iface string) error {
+	host, port, err := net.SplitHostPort(iface)
+	if err != nil {
+		return err
+	}
+
+	if chlng, ok := c.solvers[HTTP01]; ok {
+		chlng.(*httpChallenge).provider = NewHTTPProviderServer(host, port)
+	}
+
+	return nil
+}
+
+// ExcludeChallenges explicitly removes challenges from the pool for solving.
+func (c *Client) ExcludeChallenges(challenges []Challenge) {
+	// Loop through all challenges and delete the requested one if found.
+	for _, challenge := range challenges {
+		delete(c.solvers, challenge)
+	}
+}
+
+// GetToSURL returns the current ToS URL from the Directory
+func (c *Client) GetToSURL() string {
+	return c.directory.Meta.TermsOfService
+}
+
+// Register the current account to the ACME server.
+func (c *Client) Register(tosAgreed bool) (*RegistrationResource, error) {
+	if c == nil || c.user == nil {
+		return nil, errors.New("acme: cannot register a nil client or user")
+	}
+	logf("[INFO] acme: Registering account for %s", c.user.GetEmail())
+
+	accMsg := accountMessage{}
+	if c.user.GetEmail() != "" {
+		accMsg.Contact = []string{"mailto:" + c.user.GetEmail()}
+	} else {
+		accMsg.Contact = []string{}
+	}
+	accMsg.TermsOfServiceAgreed = tosAgreed
+
+	var serverReg accountMessage
+	hdr, err := postJSON(c.jws, c.directory.NewAccountURL, accMsg, &serverReg)
+	if err != nil {
+		remoteErr, ok := err.(RemoteError)
+		if ok && remoteErr.StatusCode == 409 {
+		} else {
+			return nil, err
+		}
+	}
+
+	reg := &RegistrationResource{
+		URI:  hdr.Get("Location"),
+		Body: serverReg,
+	}
+	c.jws.kid = reg.URI
+
+	return reg, nil
+}
+
+// ResolveAccountByKey will attempt to look up an account using the given account key
+// and return its registration resource.
+func (c *Client) ResolveAccountByKey() (*RegistrationResource, error) {
+	logf("[INFO] acme: Trying to resolve account by key")
+
+	acc := accountMessage{OnlyReturnExisting: true}
+	hdr, err := postJSON(c.jws, c.directory.NewAccountURL, acc, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	accountLink := hdr.Get("Location")
+	if accountLink == "" {
+		return nil, errors.New("Server did not return the account link")
+	}
+
+	var retAccount accountMessage
+	c.jws.kid = accountLink
+	hdr, err = postJSON(c.jws, accountLink, accountMessage{}, &retAccount)
+	if err != nil {
+		return nil, err
+	}
+
+	return &RegistrationResource{URI: accountLink, Body: retAccount}, nil
+}
+
+// DeleteRegistration deletes the client's user registration from the ACME
+// server.
+func (c *Client) DeleteRegistration() error {
+	if c == nil || c.user == nil {
+		return errors.New("acme: cannot unregister a nil client or user")
+	}
+	logf("[INFO] acme: Deleting account for %s", c.user.GetEmail())
+
+	accMsg := accountMessage{
+		Status: "deactivated",
+	}
+
+	_, err := postJSON(c.jws, c.user.GetRegistration().URI, accMsg, nil)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// QueryRegistration runs a POST request on the client's registration and
+// returns the result.
+//
+// This is similar to the Register function, but acting on an existing
+// registration link and resource.
+func (c *Client) QueryRegistration() (*RegistrationResource, error) {
+	if c == nil || c.user == nil {
+		return nil, errors.New("acme: cannot query the registration of a nil client or user")
+	}
+	// Log the URL here instead of the email as the email may not be set
+	logf("[INFO] acme: Querying account for %s", c.user.GetRegistration().URI)
+
+	accMsg := accountMessage{}
+
+	var serverReg accountMessage
+	_, err := postJSON(c.jws, c.user.GetRegistration().URI, accMsg, &serverReg)
+	if err != nil {
+		return nil, err
+	}
+
+	reg := &RegistrationResource{Body: serverReg}
+
+	// Location: header is not returned so this needs to be populated off of
+	// existing URI
+	reg.URI = c.user.GetRegistration().URI
+
+	return reg, nil
+}
+
+// ObtainCertificateForCSR tries to obtain a certificate matching the CSR passed into it.
+// The domains are inferred from the CommonName and SubjectAltNames, if any. The private key
+// for this CSR is not required.
+// If bundle is true, the []byte contains both the issuer certificate and
+// your issued certificate as a bundle.
+// This function will never return a partial certificate. If one domain in the list fails,
+// the whole certificate will fail.
+func (c *Client) ObtainCertificateForCSR(csr x509.CertificateRequest, bundle bool) (CertificateResource, error) {
+	// figure out what domains it concerns
+	// start with the common name
+	domains := []string{csr.Subject.CommonName}
+
+	// loop over the SubjectAltName DNS names
+DNSNames:
+	for _, sanName := range csr.DNSNames {
+		for _, existingName := range domains {
+			if existingName == sanName {
+				// duplicate; skip this name
+				continue DNSNames
+			}
+		}
+
+		// name is unique
+		domains = append(domains, sanName)
+	}
+
+	if bundle {
+		logf("[INFO][%s] acme: Obtaining bundled SAN certificate given a CSR", strings.Join(domains, ", "))
+	} else {
+		logf("[INFO][%s] acme: Obtaining SAN certificate given a CSR", strings.Join(domains, ", "))
+	}
+
+	order, err := c.createOrderForIdentifiers(domains)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+	authz, err := c.getAuthzForOrder(order)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		/*for _, auth := range authz {
+			c.disableAuthz(auth)
+		}*/
+		return CertificateResource{}, err
+	}
+
+	err = c.solveChallengeForAuthz(authz)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		return CertificateResource{}, err
+	}
+
+	logf("[INFO][%s] acme: Validations succeeded; requesting certificates", strings.Join(domains, ", "))
+
+	failures := make(ObtainError)
+	cert, err := c.requestCertificateForCsr(order, bundle, csr.Raw, nil)
+	if err != nil {
+		for _, chln := range authz {
+			failures[chln.Identifier.Value] = err
+		}
+	}
+
+	// Add the CSR to the certificate so that it can be used for renewals.
+	cert.CSR = pemEncode(&csr)
+
+	// do not return an empty failures map, because
+	// it would still be a non-nil error value
+	if len(failures) > 0 {
+		return cert, failures
+	}
+	return cert, nil
+}
+
+// ObtainCertificate tries to obtain a single certificate using all domains passed into it.
+// The first domain in domains is used for the CommonName field of the certificate, all other
+// domains are added using the Subject Alternate Names extension. A new private key is generated
+// for every invocation of this function. If you do not want that you can supply your own private key
+// in the privKey parameter. If this parameter is non-nil it will be used instead of generating a new one.
+// If bundle is true, the []byte contains both the issuer certificate and
+// your issued certificate as a bundle.
+// This function will never return a partial certificate. If one domain in the list fails,
+// the whole certificate will fail.
+func (c *Client) ObtainCertificate(domains []string, bundle bool, privKey crypto.PrivateKey, mustStaple bool) (CertificateResource, error) {
+	if len(domains) == 0 {
+		return CertificateResource{}, errors.New("No domains to obtain a certificate for")
+	}
+
+	if bundle {
+		logf("[INFO][%s] acme: Obtaining bundled SAN certificate", strings.Join(domains, ", "))
+	} else {
+		logf("[INFO][%s] acme: Obtaining SAN certificate", strings.Join(domains, ", "))
+	}
+
+	order, err := c.createOrderForIdentifiers(domains)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+	authz, err := c.getAuthzForOrder(order)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		/*for _, auth := range authz {
+			c.disableAuthz(auth)
+		}*/
+		return CertificateResource{}, err
+	}
+
+	err = c.solveChallengeForAuthz(authz)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		return CertificateResource{}, err
+	}
+
+	logf("[INFO][%s] acme: Validations succeeded; requesting certificates", strings.Join(domains, ", "))
+
+	failures := make(ObtainError)
+	cert, err := c.requestCertificateForOrder(order, bundle, privKey, mustStaple)
+	if err != nil {
+		for _, auth := range authz {
+			failures[auth.Identifier.Value] = err
+		}
+	}
+
+	// do not return an empty failures map, because
+	// it would still be a non-nil error value
+	if len(failures) > 0 {
+		return cert, failures
+	}
+	return cert, nil
+}
+
+// RevokeCertificate takes a PEM encoded certificate or bundle and tries to revoke it at the CA.
+func (c *Client) RevokeCertificate(certificate []byte) error {
+	certificates, err := parsePEMBundle(certificate)
+	if err != nil {
+		return err
+	}
+
+	x509Cert := certificates[0]
+	if x509Cert.IsCA {
+		return fmt.Errorf("Certificate bundle starts with a CA certificate")
+	}
+
+	encodedCert := base64.URLEncoding.EncodeToString(x509Cert.Raw)
+
+	_, err = postJSON(c.jws, c.directory.RevokeCertURL, revokeCertMessage{Certificate: encodedCert}, nil)
+	return err
+}
+
+// RenewCertificate takes a CertificateResource and tries to renew the certificate.
+// If the renewal process succeeds, the new certificate will ge returned in a new CertResource.
+// Please be aware that this function will return a new certificate in ANY case that is not an error.
+// If the server does not provide us with a new cert on a GET request to the CertURL
+// this function will start a new-cert flow where a new certificate gets generated.
+// If bundle is true, the []byte contains both the issuer certificate and
+// your issued certificate as a bundle.
+// For private key reuse the PrivateKey property of the passed in CertificateResource should be non-nil.
+func (c *Client) RenewCertificate(cert CertificateResource, bundle, mustStaple bool) (CertificateResource, error) {
+	// Input certificate is PEM encoded. Decode it here as we may need the decoded
+	// cert later on in the renewal process. The input may be a bundle or a single certificate.
+	certificates, err := parsePEMBundle(cert.Certificate)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	x509Cert := certificates[0]
+	if x509Cert.IsCA {
+		return CertificateResource{}, fmt.Errorf("[%s] Certificate bundle starts with a CA certificate", cert.Domain)
+	}
+
+	// This is just meant to be informal for the user.
+	timeLeft := x509Cert.NotAfter.Sub(time.Now().UTC())
+	logf("[INFO][%s] acme: Trying renewal with %d hours remaining", cert.Domain, int(timeLeft.Hours()))
+
+	// We always need to request a new certificate to renew.
+	// Start by checking to see if the certificate was based off a CSR, and
+	// use that if it's defined.
+	if len(cert.CSR) > 0 {
+		csr, err := pemDecodeTox509CSR(cert.CSR)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+		newCert, failures := c.ObtainCertificateForCSR(*csr, bundle)
+		return newCert, failures
+	}
+
+	var privKey crypto.PrivateKey
+	if cert.PrivateKey != nil {
+		privKey, err = parsePEMPrivateKey(cert.PrivateKey)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+	}
+
+	var domains []string
+	// check for SAN certificate
+	if len(x509Cert.DNSNames) > 1 {
+		domains = append(domains, x509Cert.Subject.CommonName)
+		for _, sanDomain := range x509Cert.DNSNames {
+			if sanDomain == x509Cert.Subject.CommonName {
+				continue
+			}
+			domains = append(domains, sanDomain)
+		}
+	} else {
+		domains = append(domains, x509Cert.Subject.CommonName)
+	}
+
+	newCert, err := c.ObtainCertificate(domains, bundle, privKey, mustStaple)
+	return newCert, err
+}
+
+func (c *Client) createOrderForIdentifiers(domains []string) (orderResource, error) {
+
+	var identifiers []identifier
+	for _, domain := range domains {
+		identifiers = append(identifiers, identifier{Type: "dns", Value: domain})
+	}
+
+	order := orderMessage{
+		Identifiers: identifiers,
+	}
+
+	var response orderMessage
+	hdr, err := postJSON(c.jws, c.directory.NewOrderURL, order, &response)
+	if err != nil {
+		return orderResource{}, err
+	}
+
+	orderRes := orderResource{
+		URL:          hdr.Get("Location"),
+		Domains:      domains,
+		orderMessage: response,
+	}
+	return orderRes, nil
+}
+
+// Looks through the challenge combinations to find a solvable match.
+// Then solves the challenges in series and returns.
+func (c *Client) solveChallengeForAuthz(authorizations []authorization) error {
+	failures := make(ObtainError)
+
+	// loop through the resources, basically through the domains.
+	for _, authz := range authorizations {
+		if authz.Status == "valid" {
+			// Boulder might recycle recent validated authz (see issue #267)
+			logf("[INFO][%s] acme: Authorization already valid; skipping challenge", authz.Identifier.Value)
+			continue
+		}
+
+		// no solvers - no solving
+		if i, solver := c.chooseSolver(authz, authz.Identifier.Value); solver != nil {
+			err := solver.Solve(authz.Challenges[i], authz.Identifier.Value)
+			if err != nil {
+				//c.disableAuthz(authz.Identifier)
+				failures[authz.Identifier.Value] = err
+			}
+		} else {
+			//c.disableAuthz(authz)
+			failures[authz.Identifier.Value] = fmt.Errorf("[%s] acme: Could not determine solvers", authz.Identifier.Value)
+		}
+	}
+
+	// be careful not to return an empty failures map, for
+	// even an empty ObtainError is a non-nil error value
+	if len(failures) > 0 {
+		return failures
+	}
+	return nil
+}
+
+// Checks all challenges from the server in order and returns the first matching solver.
+func (c *Client) chooseSolver(auth authorization, domain string) (int, solver) {
+	for i, challenge := range auth.Challenges {
+		if solver, ok := c.solvers[Challenge(challenge.Type)]; ok {
+			return i, solver
+		}
+		logf("[INFO][%s] acme: Could not find solver for: %s", domain, challenge.Type)
+	}
+	return 0, nil
+}
+
+// Get the challenges needed to proof our identifier to the ACME server.
+func (c *Client) getAuthzForOrder(order orderResource) ([]authorization, error) {
+	resc, errc := make(chan authorization), make(chan domainError)
+
+	delay := time.Second / overallRequestLimit
+
+	for _, authzURL := range order.Authorizations {
+		time.Sleep(delay)
+
+		go func(authzURL string) {
+			var authz authorization
+			_, err := getJSON(authzURL, &authz)
+			if err != nil {
+				errc <- domainError{Domain: authz.Identifier.Value, Error: err}
+				return
+			}
+
+			resc <- authz
+		}(authzURL)
+	}
+
+	var responses []authorization
+	failures := make(ObtainError)
+	for i := 0; i < len(order.Authorizations); i++ {
+		select {
+		case res := <-resc:
+			responses = append(responses, res)
+		case err := <-errc:
+			failures[err.Domain] = err.Error
+		}
+	}
+
+	logAuthz(order)
+
+	close(resc)
+	close(errc)
+
+	// be careful to not return an empty failures map;
+	// even if empty, they become non-nil error values
+	if len(failures) > 0 {
+		return responses, failures
+	}
+	return responses, nil
+}
+
+func logAuthz(order orderResource) {
+	for i, auth := range order.Authorizations {
+		logf("[INFO][%s] AuthURL: %s", order.Identifiers[i].Value, auth)
+	}
+}
+
+// cleanAuthz loops through the passed in slice and disables any auths which are not "valid"
+func (c *Client) disableAuthz(authURL string) error {
+	var disabledAuth authorization
+	_, err := postJSON(c.jws, authURL, deactivateAuthMessage{Status: "deactivated"}, &disabledAuth)
+	return err
+}
+
+func (c *Client) requestCertificateForOrder(order orderResource, bundle bool, privKey crypto.PrivateKey, mustStaple bool) (CertificateResource, error) {
+
+	var err error
+	if privKey == nil {
+		privKey, err = generatePrivateKey(c.keyType)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+	}
+
+	// determine certificate name(s) based on the authorization resources
+	commonName := order.Domains[0]
+	var san []string
+	for _, auth := range order.Identifiers {
+		san = append(san, auth.Value)
+	}
+
+	// TODO: should the CSR be customizable?
+	csr, err := generateCsr(privKey, commonName, san, mustStaple)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	return c.requestCertificateForCsr(order, bundle, csr, pemEncode(privKey))
+}
+
+func (c *Client) requestCertificateForCsr(order orderResource, bundle bool, csr []byte, privateKeyPem []byte) (CertificateResource, error) {
+	commonName := order.Domains[0]
+
+	csrString := base64.RawURLEncoding.EncodeToString(csr)
+	var retOrder orderMessage
+	_, error := postJSON(c.jws, order.Finalize, csrMessage{Csr: csrString}, &retOrder)
+	if error != nil {
+		return CertificateResource{}, error
+	}
+
+	if retOrder.Status == "invalid" {
+		return CertificateResource{}, error
+	}
+
+	certRes := CertificateResource{
+		Domain:     commonName,
+		CertURL:    retOrder.Certificate,
+		PrivateKey: privateKeyPem,
+	}
+
+	if retOrder.Status == "valid" {
+		// if the certificate is available right away, short cut!
+		ok, err := c.checkCertResponse(retOrder, &certRes, bundle)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+
+		if ok {
+			return certRes, nil
+		}
+	}
+
+	maxChecks := 1000
+	for i := 0; i < maxChecks; i++ {
+		_, err := getJSON(order.URL, &retOrder)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+		done, err := c.checkCertResponse(retOrder, &certRes, bundle)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+		if done {
+			break
+		}
+		if i == maxChecks-1 {
+			return CertificateResource{}, fmt.Errorf("polled for certificate %d times; giving up", i)
+		}
+	}
+
+	return certRes, nil
+}
+
+// checkCertResponse checks to see if the certificate is ready and a link is contained in the
+// response. if so, loads it into certRes and returns true. If the cert
+// is not yet ready, it returns false. The certRes input
+// should already have the Domain (common name) field populated. If bundle is
+// true, the certificate will be bundled with the issuer's cert.
+func (c *Client) checkCertResponse(order orderMessage, certRes *CertificateResource, bundle bool) (bool, error) {
+
+	switch order.Status {
+	case "valid":
+		resp, err := httpGet(order.Certificate)
+		if err != nil {
+			return false, err
+		}
+
+		cert, err := ioutil.ReadAll(limitReader(resp.Body, maxBodySize))
+		if err != nil {
+			return false, err
+		}
+
+		// The issuer certificate link is always supplied via an "up" link
+		// in the response headers of a new certificate.
+		links := parseLinks(resp.Header["Link"])
+		if link, ok := links["up"]; ok {
+			issuerCert, err := c.getIssuerCertificate(link)
+
+			if err != nil {
+				// If we fail to acquire the issuer cert, return the issued certificate - do not fail.
+				logf("[WARNING][%s] acme: Could not bundle issuer certificate: %v", certRes.Domain, err)
+			} else {
+				issuerCert = pemEncode(derCertificateBytes(issuerCert))
+
+				// If bundle is true, we want to return a certificate bundle.
+				// To do this, we append the issuer cert to the issued cert.
+				if bundle {
+					cert = append(cert, issuerCert...)
+				}
+
+				certRes.IssuerCertificate = issuerCert
+			}
+		}
+
+		certRes.Certificate = cert
+		certRes.CertURL = order.Certificate
+		certRes.CertStableURL = order.Certificate
+		logf("[INFO][%s] Server responded with a certificate.", certRes.Domain)
+		return true, nil
+
+	case "processing":
+		return false, nil
+	case "invalid":
+		return false, errors.New("Order has invalid state: invalid")
+	}
+
+	return false, nil
+}
+
+// getIssuerCertificate requests the issuer certificate
+func (c *Client) getIssuerCertificate(url string) ([]byte, error) {
+	logf("[INFO] acme: Requesting issuer cert from %s", url)
+	resp, err := httpGet(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	issuerBytes, err := ioutil.ReadAll(limitReader(resp.Body, maxBodySize))
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = x509.ParseCertificate(issuerBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	return issuerBytes, err
+}
+
+func parseLinks(links []string) map[string]string {
+	aBrkt := regexp.MustCompile("[<>]")
+	slver := regexp.MustCompile("(.+) *= *\"(.+)\"")
+	linkMap := make(map[string]string)
+
+	for _, link := range links {
+
+		link = aBrkt.ReplaceAllString(link, "")
+		parts := strings.Split(link, ";")
+
+		matches := slver.FindStringSubmatch(parts[1])
+		if len(matches) > 0 {
+			linkMap[matches[2]] = parts[0]
+		}
+	}
+
+	return linkMap
+}
+
+// validate makes the ACME server start validating a
+// challenge response, only returning once it is done.
+func validate(j *jws, domain, uri string, c challenge) error {
+	var chlng challenge
+
+	hdr, err := postJSON(j, uri, c, &chlng)
+	if err != nil {
+		return err
+	}
+
+	// After the path is sent, the ACME server will access our server.
+	// Repeatedly check the server for an updated status on our request.
+	for {
+		switch chlng.Status {
+		case "valid":
+			logf("[INFO][%s] The server validated our request", domain)
+			return nil
+		case "pending":
+			break
+		case "invalid":
+			return handleChallengeError(chlng)
+		default:
+			return errors.New("The server returned an unexpected state")
+		}
+
+		ra, err := strconv.Atoi(hdr.Get("Retry-After"))
+		if err != nil {
+			// The ACME server MUST return a Retry-After.
+			// If it doesn't, we'll just poll hard.
+			ra = 5
+		}
+		time.Sleep(time.Duration(ra) * time.Second)
+
+		hdr, err = getJSON(uri, &chlng)
+		if err != nil {
+			return err
+		}
+	}
+}

vendor/github.com/xenolf/lego/acmev2/crypto.go

@@ -0,0 +1,343 @@
+package acme
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/base64"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/big"
+	"net/http"
+	"time"
+
+	"encoding/asn1"
+
+	"golang.org/x/crypto/ocsp"
+	jose "gopkg.in/square/go-jose.v2"
+)
+
+// KeyType represents the key algo as well as the key size or curve to use.
+type KeyType string
+type derCertificateBytes []byte
+
+// Constants for all key types we support.
+const (
+	EC256   = KeyType("P256")
+	EC384   = KeyType("P384")
+	RSA2048 = KeyType("2048")
+	RSA4096 = KeyType("4096")
+	RSA8192 = KeyType("8192")
+)
+
+const (
+	// OCSPGood means that the certificate is valid.
+	OCSPGood = ocsp.Good
+	// OCSPRevoked means that the certificate has been deliberately revoked.
+	OCSPRevoked = ocsp.Revoked
+	// OCSPUnknown means that the OCSP responder doesn't know about the certificate.
+	OCSPUnknown = ocsp.Unknown
+	// OCSPServerFailed means that the OCSP responder failed to process the request.
+	OCSPServerFailed = ocsp.ServerFailed
+)
+
+// Constants for OCSP must staple
+var (
+	tlsFeatureExtensionOID = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 24}
+	ocspMustStapleFeature  = []byte{0x30, 0x03, 0x02, 0x01, 0x05}
+)
+
+// GetOCSPForCert takes a PEM encoded cert or cert bundle returning the raw OCSP response,
+// the parsed response, and an error, if any. The returned []byte can be passed directly
+// into the OCSPStaple property of a tls.Certificate. If the bundle only contains the
+// issued certificate, this function will try to get the issuer certificate from the
+// IssuingCertificateURL in the certificate. If the []byte and/or ocsp.Response return
+// values are nil, the OCSP status may be assumed OCSPUnknown.
+func GetOCSPForCert(bundle []byte) ([]byte, *ocsp.Response, error) {
+	certificates, err := parsePEMBundle(bundle)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// We expect the certificate slice to be ordered downwards the chain.
+	// SRV CRT -> CA. We need to pull the leaf and issuer certs out of it,
+	// which should always be the first two certificates. If there's no
+	// OCSP server listed in the leaf cert, there's nothing to do. And if
+	// we have only one certificate so far, we need to get the issuer cert.
+	issuedCert := certificates[0]
+	if len(issuedCert.OCSPServer) == 0 {
+		return nil, nil, errors.New("no OCSP server specified in cert")
+	}
+	if len(certificates) == 1 {
+		// TODO: build fallback. If this fails, check the remaining array entries.
+		if len(issuedCert.IssuingCertificateURL) == 0 {
+			return nil, nil, errors.New("no issuing certificate URL")
+		}
+
+		resp, err := httpGet(issuedCert.IssuingCertificateURL[0])
+		if err != nil {
+			return nil, nil, err
+		}
+		defer resp.Body.Close()
+
+		issuerBytes, err := ioutil.ReadAll(limitReader(resp.Body, 1024*1024))
+		if err != nil {
+			return nil, nil, err
+		}
+
+		issuerCert, err := x509.ParseCertificate(issuerBytes)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		// Insert it into the slice on position 0
+		// We want it ordered right SRV CRT -> CA
+		certificates = append(certificates, issuerCert)
+	}
+	issuerCert := certificates[1]
+
+	// Finally kick off the OCSP request.
+	ocspReq, err := ocsp.CreateRequest(issuedCert, issuerCert, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	reader := bytes.NewReader(ocspReq)
+	req, err := httpPost(issuedCert.OCSPServer[0], "application/ocsp-request", reader)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer req.Body.Close()
+
+	ocspResBytes, err := ioutil.ReadAll(limitReader(req.Body, 1024*1024))
+	ocspRes, err := ocsp.ParseResponse(ocspResBytes, issuerCert)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return ocspResBytes, ocspRes, nil
+}
+
+func getKeyAuthorization(token string, key interface{}) (string, error) {
+	var publicKey crypto.PublicKey
+	switch k := key.(type) {
+	case *ecdsa.PrivateKey:
+		publicKey = k.Public()
+	case *rsa.PrivateKey:
+		publicKey = k.Public()
+	}
+
+	// Generate the Key Authorization for the challenge
+	jwk := &jose.JSONWebKey{Key: publicKey}
+	if jwk == nil {
+		return "", errors.New("Could not generate JWK from key")
+	}
+	thumbBytes, err := jwk.Thumbprint(crypto.SHA256)
+	if err != nil {
+		return "", err
+	}
+
+	// unpad the base64URL
+	keyThumb := base64.RawURLEncoding.EncodeToString(thumbBytes)
+
+	return token + "." + keyThumb, nil
+}
+
+// parsePEMBundle parses a certificate bundle from top to bottom and returns
+// a slice of x509 certificates. This function will error if no certificates are found.
+func parsePEMBundle(bundle []byte) ([]*x509.Certificate, error) {
+	var certificates []*x509.Certificate
+	var certDERBlock *pem.Block
+
+	for {
+		certDERBlock, bundle = pem.Decode(bundle)
+		if certDERBlock == nil {
+			break
+		}
+
+		if certDERBlock.Type == "CERTIFICATE" {
+			cert, err := x509.ParseCertificate(certDERBlock.Bytes)
+			if err != nil {
+				return nil, err
+			}
+			certificates = append(certificates, cert)
+		}
+	}
+
+	if len(certificates) == 0 {
+		return nil, errors.New("No certificates were found while parsing the bundle")
+	}
+
+	return certificates, nil
+}
+
+func parsePEMPrivateKey(key []byte) (crypto.PrivateKey, error) {
+	keyBlock, _ := pem.Decode(key)
+
+	switch keyBlock.Type {
+	case "RSA PRIVATE KEY":
+		return x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
+	case "EC PRIVATE KEY":
+		return x509.ParseECPrivateKey(keyBlock.Bytes)
+	default:
+		return nil, errors.New("Unknown PEM header value")
+	}
+}
+
+func generatePrivateKey(keyType KeyType) (crypto.PrivateKey, error) {
+
+	switch keyType {
+	case EC256:
+		return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	case EC384:
+		return ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+	case RSA2048:
+		return rsa.GenerateKey(rand.Reader, 2048)
+	case RSA4096:
+		return rsa.GenerateKey(rand.Reader, 4096)
+	case RSA8192:
+		return rsa.GenerateKey(rand.Reader, 8192)
+	}
+
+	return nil, fmt.Errorf("Invalid KeyType: %s", keyType)
+}
+
+func generateCsr(privateKey crypto.PrivateKey, domain string, san []string, mustStaple bool) ([]byte, error) {
+	template := x509.CertificateRequest{
+		Subject: pkix.Name{
+			CommonName: domain,
+		},
+	}
+
+	if len(san) > 0 {
+		template.DNSNames = san
+	}
+
+	if mustStaple {
+		template.ExtraExtensions = append(template.ExtraExtensions, pkix.Extension{
+			Id:    tlsFeatureExtensionOID,
+			Value: ocspMustStapleFeature,
+		})
+	}
+
+	return x509.CreateCertificateRequest(rand.Reader, &template, privateKey)
+}
+
+func pemEncode(data interface{}) []byte {
+	var pemBlock *pem.Block
+	switch key := data.(type) {
+	case *ecdsa.PrivateKey:
+		keyBytes, _ := x509.MarshalECPrivateKey(key)
+		pemBlock = &pem.Block{Type: "EC PRIVATE KEY", Bytes: keyBytes}
+	case *rsa.PrivateKey:
+		pemBlock = &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}
+		break
+	case *x509.CertificateRequest:
+		pemBlock = &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: key.Raw}
+		break
+	case derCertificateBytes:
+		pemBlock = &pem.Block{Type: "CERTIFICATE", Bytes: []byte(data.(derCertificateBytes))}
+	}
+
+	return pem.EncodeToMemory(pemBlock)
+}
+
+func pemDecode(data []byte) (*pem.Block, error) {
+	pemBlock, _ := pem.Decode(data)
+	if pemBlock == nil {
+		return nil, fmt.Errorf("Pem decode did not yield a valid block. Is the certificate in the right format?")
+	}
+
+	return pemBlock, nil
+}
+
+func pemDecodeTox509(pem []byte) (*x509.Certificate, error) {
+	pemBlock, err := pemDecode(pem)
+	if pemBlock == nil {
+		return nil, err
+	}
+
+	return x509.ParseCertificate(pemBlock.Bytes)
+}
+
+func pemDecodeTox509CSR(pem []byte) (*x509.CertificateRequest, error) {
+	pemBlock, err := pemDecode(pem)
+	if pemBlock == nil {
+		return nil, err
+	}
+
+	if pemBlock.Type != "CERTIFICATE REQUEST" {
+		return nil, fmt.Errorf("PEM block is not a certificate request")
+	}
+
+	return x509.ParseCertificateRequest(pemBlock.Bytes)
+}
+
+// GetPEMCertExpiration returns the "NotAfter" date of a PEM encoded certificate.
+// The certificate has to be PEM encoded. Any other encodings like DER will fail.
+func GetPEMCertExpiration(cert []byte) (time.Time, error) {
+	pemBlock, err := pemDecode(cert)
+	if pemBlock == nil {
+		return time.Time{}, err
+	}
+
+	return getCertExpiration(pemBlock.Bytes)
+}
+
+// getCertExpiration returns the "NotAfter" date of a DER encoded certificate.
+func getCertExpiration(cert []byte) (time.Time, error) {
+	pCert, err := x509.ParseCertificate(cert)
+	if err != nil {
+		return time.Time{}, err
+	}
+
+	return pCert.NotAfter, nil
+}
+
+func generatePemCert(privKey *rsa.PrivateKey, domain string) ([]byte, error) {
+	derBytes, err := generateDerCert(privKey, time.Time{}, domain)
+	if err != nil {
+		return nil, err
+	}
+
+	return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes}), nil
+}
+
+func generateDerCert(privKey *rsa.PrivateKey, expiration time.Time, domain string) ([]byte, error) {
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
+	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		return nil, err
+	}
+
+	if expiration.IsZero() {
+		expiration = time.Now().Add(365)
+	}
+
+	template := x509.Certificate{
+		SerialNumber: serialNumber,
+		Subject: pkix.Name{
+			CommonName: "ACME Challenge TEMP",
+		},
+		NotBefore: time.Now(),
+		NotAfter:  expiration,
+
+		KeyUsage:              x509.KeyUsageKeyEncipherment,
+		BasicConstraintsValid: true,
+		DNSNames:              []string{domain},
+	}
+
+	return x509.CreateCertificate(rand.Reader, &template, &template, &privKey.PublicKey, privKey)
+}
+
+func limitReader(rd io.ReadCloser, numBytes int64) io.ReadCloser {
+	return http.MaxBytesReader(nil, rd, numBytes)
+}

vendor/github.com/xenolf/lego/acmev2/dns_challenge.go

@@ -0,0 +1,309 @@
+package acme
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/miekg/dns"
+)
+
+type preCheckDNSFunc func(fqdn, value string) (bool, error)
+
+var (
+	// PreCheckDNS checks DNS propagation before notifying ACME that
+	// the DNS challenge is ready.
+	PreCheckDNS preCheckDNSFunc = checkDNSPropagation
+	fqdnToZone                  = map[string]string{}
+)
+
+const defaultResolvConf = "/etc/resolv.conf"
+
+var defaultNameservers = []string{
+	"google-public-dns-a.google.com:53",
+	"google-public-dns-b.google.com:53",
+}
+
+// RecursiveNameservers are used to pre-check DNS propagations
+var RecursiveNameservers = getNameservers(defaultResolvConf, defaultNameservers)
+
+// DNSTimeout is used to override the default DNS timeout of 10 seconds.
+var DNSTimeout = 10 * time.Second
+
+// getNameservers attempts to get systems nameservers before falling back to the defaults
+func getNameservers(path string, defaults []string) []string {
+	config, err := dns.ClientConfigFromFile(path)
+	if err != nil || len(config.Servers) == 0 {
+		return defaults
+	}
+
+	systemNameservers := []string{}
+	for _, server := range config.Servers {
+		// ensure all servers have a port number
+		if _, _, err := net.SplitHostPort(server); err != nil {
+			systemNameservers = append(systemNameservers, net.JoinHostPort(server, "53"))
+		} else {
+			systemNameservers = append(systemNameservers, server)
+		}
+	}
+	return systemNameservers
+}
+
+// DNS01Record returns a DNS record which will fulfill the `dns-01` challenge
+func DNS01Record(domain, keyAuth string) (fqdn string, value string, ttl int) {
+	keyAuthShaBytes := sha256.Sum256([]byte(keyAuth))
+	// base64URL encoding without padding
+	value = base64.RawURLEncoding.EncodeToString(keyAuthShaBytes[:sha256.Size])
+	ttl = 120
+	fqdn = fmt.Sprintf("_acme-challenge.%s.", domain)
+	return
+}
+
+// dnsChallenge implements the dns-01 challenge according to ACME 7.5
+type dnsChallenge struct {
+	jws      *jws
+	validate validateFunc
+	provider ChallengeProvider
+}
+
+func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
+	logf("[INFO][%s] acme: Trying to solve DNS-01", domain)
+
+	if s.provider == nil {
+		return errors.New("No DNS Provider configured")
+	}
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := getKeyAuthorization(chlng.Token, s.jws.privKey)
+	if err != nil {
+		return err
+	}
+
+	err = s.provider.Present(domain, chlng.Token, keyAuth)
+	if err != nil {
+		return fmt.Errorf("Error presenting token: %s", err)
+	}
+	defer func() {
+		err := s.provider.CleanUp(domain, chlng.Token, keyAuth)
+		if err != nil {
+			log.Printf("Error cleaning up %s: %v ", domain, err)
+		}
+	}()
+
+	fqdn, value, _ := DNS01Record(domain, keyAuth)
+
+	logf("[INFO][%s] Checking DNS record propagation using %+v", domain, RecursiveNameservers)
+
+	var timeout, interval time.Duration
+	switch provider := s.provider.(type) {
+	case ChallengeProviderTimeout:
+		timeout, interval = provider.Timeout()
+	default:
+		timeout, interval = 60*time.Second, 2*time.Second
+	}
+
+	err = WaitFor(timeout, interval, func() (bool, error) {
+		return PreCheckDNS(fqdn, value)
+	})
+	if err != nil {
+		return err
+	}
+
+	return s.validate(s.jws, domain, chlng.URL, challenge{Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
+}
+
+// checkDNSPropagation checks if the expected TXT record has been propagated to all authoritative nameservers.
+func checkDNSPropagation(fqdn, value string) (bool, error) {
+	// Initial attempt to resolve at the recursive NS
+	r, err := dnsQuery(fqdn, dns.TypeTXT, RecursiveNameservers, true)
+	if err != nil {
+		return false, err
+	}
+	if r.Rcode == dns.RcodeSuccess {
+		// If we see a CNAME here then use the alias
+		for _, rr := range r.Answer {
+			if cn, ok := rr.(*dns.CNAME); ok {
+				if cn.Hdr.Name == fqdn {
+					fqdn = cn.Target
+					break
+				}
+			}
+		}
+	}
+
+	authoritativeNss, err := lookupNameservers(fqdn)
+	if err != nil {
+		return false, err
+	}
+
+	return checkAuthoritativeNss(fqdn, value, authoritativeNss)
+}
+
+// checkAuthoritativeNss queries each of the given nameservers for the expected TXT record.
+func checkAuthoritativeNss(fqdn, value string, nameservers []string) (bool, error) {
+	for _, ns := range nameservers {
+		r, err := dnsQuery(fqdn, dns.TypeTXT, []string{net.JoinHostPort(ns, "53")}, false)
+		if err != nil {
+			return false, err
+		}
+
+		if r.Rcode != dns.RcodeSuccess {
+			return false, fmt.Errorf("NS %s returned %s for %s", ns, dns.RcodeToString[r.Rcode], fqdn)
+		}
+
+		var found bool
+		for _, rr := range r.Answer {
+			if txt, ok := rr.(*dns.TXT); ok {
+				if strings.Join(txt.Txt, "") == value {
+					found = true
+					break
+				}
+			}
+		}
+
+		if !found {
+			return false, fmt.Errorf("NS %s did not return the expected TXT record", ns)
+		}
+	}
+
+	return true, nil
+}
+
+// dnsQuery will query a nameserver, iterating through the supplied servers as it retries
+// The nameserver should include a port, to facilitate testing where we talk to a mock dns server.
+func dnsQuery(fqdn string, rtype uint16, nameservers []string, recursive bool) (in *dns.Msg, err error) {
+	m := new(dns.Msg)
+	m.SetQuestion(fqdn, rtype)
+	m.SetEdns0(4096, false)
+
+	if !recursive {
+		m.RecursionDesired = false
+	}
+
+	// Will retry the request based on the number of servers (n+1)
+	for i := 1; i <= len(nameservers)+1; i++ {
+		ns := nameservers[i%len(nameservers)]
+		udp := &dns.Client{Net: "udp", Timeout: DNSTimeout}
+		in, _, err = udp.Exchange(m, ns)
+
+		if err == dns.ErrTruncated {
+			tcp := &dns.Client{Net: "tcp", Timeout: DNSTimeout}
+			// If the TCP request succeeds, the err will reset to nil
+			in, _, err = tcp.Exchange(m, ns)
+		}
+
+		if err == nil {
+			break
+		}
+	}
+	return
+}
+
+// lookupNameservers returns the authoritative nameservers for the given fqdn.
+func lookupNameservers(fqdn string) ([]string, error) {
+	var authoritativeNss []string
+
+	zone, err := FindZoneByFqdn(fqdn, RecursiveNameservers)
+	if err != nil {
+		return nil, fmt.Errorf("Could not determine the zone: %v", err)
+	}
+
+	r, err := dnsQuery(zone, dns.TypeNS, RecursiveNameservers, true)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, rr := range r.Answer {
+		if ns, ok := rr.(*dns.NS); ok {
+			authoritativeNss = append(authoritativeNss, strings.ToLower(ns.Ns))
+		}
+	}
+
+	if len(authoritativeNss) > 0 {
+		return authoritativeNss, nil
+	}
+	return nil, fmt.Errorf("Could not determine authoritative nameservers")
+}
+
+// FindZoneByFqdn determines the zone apex for the given fqdn by recursing up the
+// domain labels until the nameserver returns a SOA record in the answer section.
+func FindZoneByFqdn(fqdn string, nameservers []string) (string, error) {
+	// Do we have it cached?
+	if zone, ok := fqdnToZone[fqdn]; ok {
+		return zone, nil
+	}
+
+	labelIndexes := dns.Split(fqdn)
+	for _, index := range labelIndexes {
+		domain := fqdn[index:]
+
+		in, err := dnsQuery(domain, dns.TypeSOA, nameservers, true)
+		if err != nil {
+			return "", err
+		}
+
+		// Any response code other than NOERROR and NXDOMAIN is treated as error
+		if in.Rcode != dns.RcodeNameError && in.Rcode != dns.RcodeSuccess {
+			return "", fmt.Errorf("Unexpected response code '%s' for %s",
+				dns.RcodeToString[in.Rcode], domain)
+		}
+
+		// Check if we got a SOA RR in the answer section
+		if in.Rcode == dns.RcodeSuccess {
+
+			// CNAME records cannot/should not exist at the root of a zone.
+			// So we skip a domain when a CNAME is found.
+			if dnsMsgContainsCNAME(in) {
+				continue
+			}
+
+			for _, ans := range in.Answer {
+				if soa, ok := ans.(*dns.SOA); ok {
+					zone := soa.Hdr.Name
+					fqdnToZone[fqdn] = zone
+					return zone, nil
+				}
+			}
+		}
+	}
+
+	return "", fmt.Errorf("Could not find the start of authority")
+}
+
+// dnsMsgContainsCNAME checks for a CNAME answer in msg
+func dnsMsgContainsCNAME(msg *dns.Msg) bool {
+	for _, ans := range msg.Answer {
+		if _, ok := ans.(*dns.CNAME); ok {
+			return true
+		}
+	}
+	return false
+}
+
+// ClearFqdnCache clears the cache of fqdn to zone mappings. Primarily used in testing.
+func ClearFqdnCache() {
+	fqdnToZone = map[string]string{}
+}
+
+// ToFqdn converts the name into a fqdn appending a trailing dot.
+func ToFqdn(name string) string {
+	n := len(name)
+	if n == 0 || name[n-1] == '.' {
+		return name
+	}
+	return name + "."
+}
+
+// UnFqdn converts the fqdn into a name removing the trailing dot.
+func UnFqdn(name string) string {
+	n := len(name)
+	if n != 0 && name[n-1] == '.' {
+		return name[:n-1]
+	}
+	return name
+}

vendor/github.com/xenolf/lego/acmev2/dns_challenge_manual.go

@@ -0,0 +1,53 @@
+package acme
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+const (
+	dnsTemplate = "%s %d IN TXT \"%s\""
+)
+
+// DNSProviderManual is an implementation of the ChallengeProvider interface
+type DNSProviderManual struct{}
+
+// NewDNSProviderManual returns a DNSProviderManual instance.
+func NewDNSProviderManual() (*DNSProviderManual, error) {
+	return &DNSProviderManual{}, nil
+}
+
+// Present prints instructions for manually creating the TXT record
+func (*DNSProviderManual) Present(domain, token, keyAuth string) error {
+	fqdn, value, ttl := DNS01Record(domain, keyAuth)
+	dnsRecord := fmt.Sprintf(dnsTemplate, fqdn, ttl, value)
+
+	authZone, err := FindZoneByFqdn(fqdn, RecursiveNameservers)
+	if err != nil {
+		return err
+	}
+
+	logf("[INFO] acme: Please create the following TXT record in your %s zone:", authZone)
+	logf("[INFO] acme: %s", dnsRecord)
+	logf("[INFO] acme: Press 'Enter' when you are done")
+
+	reader := bufio.NewReader(os.Stdin)
+	_, _ = reader.ReadString('\n')
+	return nil
+}
+
+// CleanUp prints instructions for manually removing the TXT record
+func (*DNSProviderManual) CleanUp(domain, token, keyAuth string) error {
+	fqdn, _, ttl := DNS01Record(domain, keyAuth)
+	dnsRecord := fmt.Sprintf(dnsTemplate, fqdn, ttl, "...")
+
+	authZone, err := FindZoneByFqdn(fqdn, RecursiveNameservers)
+	if err != nil {
+		return err
+	}
+
+	logf("[INFO] acme: You can now remove this TXT record from your %s zone:", authZone)
+	logf("[INFO] acme: %s", dnsRecord)
+	return nil
+}

vendor/github.com/xenolf/lego/acmev2/error.go

@@ -0,0 +1,91 @@
+package acme
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+)
+
+const (
+	tosAgreementError = "Terms of service have changed"
+	invalidNonceError = "urn:ietf:params:acme:error:badNonce"
+)
+
+// RemoteError is the base type for all errors specific to the ACME protocol.
+type RemoteError struct {
+	StatusCode int    `json:"status,omitempty"`
+	Type       string `json:"type"`
+	Detail     string `json:"detail"`
+}
+
+func (e RemoteError) Error() string {
+	return fmt.Sprintf("acme: Error %d - %s - %s", e.StatusCode, e.Type, e.Detail)
+}
+
+// TOSError represents the error which is returned if the user needs to
+// accept the TOS.
+// TODO: include the new TOS url if we can somehow obtain it.
+type TOSError struct {
+	RemoteError
+}
+
+// NonceError represents the error which is returned if the
+// nonce sent by the client was not accepted by the server.
+type NonceError struct {
+	RemoteError
+}
+
+type domainError struct {
+	Domain string
+	Error  error
+}
+
+// ObtainError is returned when there are specific errors available
+// per domain. For example in ObtainCertificate
+type ObtainError map[string]error
+
+func (e ObtainError) Error() string {
+	buffer := bytes.NewBufferString("acme: Error -> One or more domains had a problem:\n")
+	for dom, err := range e {
+		buffer.WriteString(fmt.Sprintf("[%s] %s\n", dom, err))
+	}
+	return buffer.String()
+}
+
+func handleHTTPError(resp *http.Response) error {
+	var errorDetail RemoteError
+
+	contentType := resp.Header.Get("Content-Type")
+	if contentType == "application/json" || strings.HasPrefix(contentType, "application/problem+json") {
+		err := json.NewDecoder(resp.Body).Decode(&errorDetail)
+		if err != nil {
+			return err
+		}
+	} else {
+		detailBytes, err := ioutil.ReadAll(limitReader(resp.Body, maxBodySize))
+		if err != nil {
+			return err
+		}
+		errorDetail.Detail = string(detailBytes)
+	}
+
+	errorDetail.StatusCode = resp.StatusCode
+
+	// Check for errors we handle specifically
+	if errorDetail.StatusCode == http.StatusForbidden && errorDetail.Detail == tosAgreementError {
+		return TOSError{errorDetail}
+	}
+
+	if errorDetail.StatusCode == http.StatusBadRequest && errorDetail.Type == invalidNonceError {
+		return NonceError{errorDetail}
+	}
+
+	return errorDetail
+}
+
+func handleChallengeError(chlng challenge) error {
+	return chlng.Error
+}

vendor/github.com/xenolf/lego/acmev2/http.go

@@ -0,0 +1,160 @@
+package acme
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"runtime"
+	"strings"
+	"time"
+)
+
+// UserAgent (if non-empty) will be tacked onto the User-Agent string in requests.
+var UserAgent string
+
+// HTTPClient is an HTTP client with a reasonable timeout value.
+var HTTPClient = http.Client{
+	Transport: &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		Dial: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+		}).Dial,
+		TLSHandshakeTimeout:   15 * time.Second,
+		ResponseHeaderTimeout: 15 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+	},
+}
+
+const (
+	// defaultGoUserAgent is the Go HTTP package user agent string. Too
+	// bad it isn't exported. If it changes, we should update it here, too.
+	defaultGoUserAgent = "Go-http-client/1.1"
+
+	// ourUserAgent is the User-Agent of this underlying library package.
+	ourUserAgent = "xenolf-acme"
+)
+
+// httpHead performs a HEAD request with a proper User-Agent string.
+// The response body (resp.Body) is already closed when this function returns.
+func httpHead(url string) (resp *http.Response, err error) {
+	req, err := http.NewRequest("HEAD", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to head %q: %v", url, err)
+	}
+
+	req.Header.Set("User-Agent", userAgent())
+
+	resp, err = HTTPClient.Do(req)
+	if err != nil {
+		return resp, fmt.Errorf("failed to do head %q: %v", url, err)
+	}
+	resp.Body.Close()
+	return resp, err
+}
+
+// httpPost performs a POST request with a proper User-Agent string.
+// Callers should close resp.Body when done reading from it.
+func httpPost(url string, bodyType string, body io.Reader) (resp *http.Response, err error) {
+	req, err := http.NewRequest("POST", url, body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to post %q: %v", url, err)
+	}
+	req.Header.Set("Content-Type", bodyType)
+	req.Header.Set("User-Agent", userAgent())
+
+	return HTTPClient.Do(req)
+}
+
+// httpGet performs a GET request with a proper User-Agent string.
+// Callers should close resp.Body when done reading from it.
+func httpGet(url string) (resp *http.Response, err error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get %q: %v", url, err)
+	}
+	req.Header.Set("User-Agent", userAgent())
+
+	return HTTPClient.Do(req)
+}
+
+// getJSON performs an HTTP GET request and parses the response body
+// as JSON, into the provided respBody object.
+func getJSON(uri string, respBody interface{}) (http.Header, error) {
+	resp, err := httpGet(uri)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get json %q: %v", uri, err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= http.StatusBadRequest {
+		return resp.Header, handleHTTPError(resp)
+	}
+
+	return resp.Header, json.NewDecoder(resp.Body).Decode(respBody)
+}
+
+// postJSON performs an HTTP POST request and parses the response body
+// as JSON, into the provided respBody object.
+func postJSON(j *jws, uri string, reqBody, respBody interface{}) (http.Header, error) {
+	jsonBytes, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, errors.New("Failed to marshal network message")
+	}
+
+	resp, err := j.post(uri, jsonBytes)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to post JWS message. -> %v", err)
+	}
+
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= http.StatusBadRequest {
+
+		err := handleHTTPError(resp)
+
+		switch err.(type) {
+
+		case NonceError:
+
+			// Retry once if the nonce was invalidated
+
+			retryResp, err := j.post(uri, jsonBytes)
+			if err != nil {
+				return nil, fmt.Errorf("Failed to post JWS message. -> %v", err)
+			}
+
+			defer retryResp.Body.Close()
+
+			if retryResp.StatusCode >= http.StatusBadRequest {
+				return retryResp.Header, handleHTTPError(retryResp)
+			}
+
+			if respBody == nil {
+				return retryResp.Header, nil
+			}
+
+			return retryResp.Header, json.NewDecoder(retryResp.Body).Decode(respBody)
+
+		default:
+			return resp.Header, err
+
+		}
+
+	}
+
+	if respBody == nil {
+		return resp.Header, nil
+	}
+
+	return resp.Header, json.NewDecoder(resp.Body).Decode(respBody)
+}
+
+// userAgent builds and returns the User-Agent string to use in requests.
+func userAgent() string {
+	ua := fmt.Sprintf("%s (%s; %s) %s %s", defaultGoUserAgent, runtime.GOOS, runtime.GOARCH, ourUserAgent, UserAgent)
+	return strings.TrimSpace(ua)
+}

vendor/github.com/xenolf/lego/acmev2/http_challenge.go

@@ -0,0 +1,41 @@
+package acme
+
+import (
+	"fmt"
+	"log"
+)
+
+type httpChallenge struct {
+	jws      *jws
+	validate validateFunc
+	provider ChallengeProvider
+}
+
+// HTTP01ChallengePath returns the URL path for the `http-01` challenge
+func HTTP01ChallengePath(token string) string {
+	return "/.well-known/acme-challenge/" + token
+}
+
+func (s *httpChallenge) Solve(chlng challenge, domain string) error {
+
+	logf("[INFO][%s] acme: Trying to solve HTTP-01", domain)
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := getKeyAuthorization(chlng.Token, s.jws.privKey)
+	if err != nil {
+		return err
+	}
+
+	err = s.provider.Present(domain, chlng.Token, keyAuth)
+	if err != nil {
+		return fmt.Errorf("[%s] error presenting token: %v", domain, err)
+	}
+	defer func() {
+		err := s.provider.CleanUp(domain, chlng.Token, keyAuth)
+		if err != nil {
+			log.Printf("[%s] error cleaning up: %v", domain, err)
+		}
+	}()
+
+	return s.validate(s.jws, domain, chlng.URL, challenge{Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
+}

vendor/github.com/xenolf/lego/acmev2/http_challenge_server.go

@@ -0,0 +1,79 @@
+package acme
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"strings"
+)
+
+// HTTPProviderServer implements ChallengeProvider for `http-01` challenge
+// It may be instantiated without using the NewHTTPProviderServer function if
+// you want only to use the default values.
+type HTTPProviderServer struct {
+	iface    string
+	port     string
+	done     chan bool
+	listener net.Listener
+}
+
+// NewHTTPProviderServer creates a new HTTPProviderServer on the selected interface and port.
+// Setting iface and / or port to an empty string will make the server fall back to
+// the "any" interface and port 80 respectively.
+func NewHTTPProviderServer(iface, port string) *HTTPProviderServer {
+	return &HTTPProviderServer{iface: iface, port: port}
+}
+
+// Present starts a web server and makes the token available at `HTTP01ChallengePath(token)` for web requests.
+func (s *HTTPProviderServer) Present(domain, token, keyAuth string) error {
+	if s.port == "" {
+		s.port = "80"
+	}
+
+	var err error
+	s.listener, err = net.Listen("tcp", net.JoinHostPort(s.iface, s.port))
+	if err != nil {
+		return fmt.Errorf("Could not start HTTP server for challenge -> %v", err)
+	}
+
+	s.done = make(chan bool)
+	go s.serve(domain, token, keyAuth)
+	return nil
+}
+
+// CleanUp closes the HTTP server and removes the token from `HTTP01ChallengePath(token)`
+func (s *HTTPProviderServer) CleanUp(domain, token, keyAuth string) error {
+	if s.listener == nil {
+		return nil
+	}
+	s.listener.Close()
+	<-s.done
+	return nil
+}
+
+func (s *HTTPProviderServer) serve(domain, token, keyAuth string) {
+	path := HTTP01ChallengePath(token)
+
+	// The handler validates the HOST header and request type.
+	// For validation it then writes the token the server returned with the challenge
+	mux := http.NewServeMux()
+	mux.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
+		if strings.HasPrefix(r.Host, domain) && r.Method == "GET" {
+			w.Header().Add("Content-Type", "text/plain")
+			w.Write([]byte(keyAuth))
+			logf("[INFO][%s] Served key authentication", domain)
+		} else {
+			logf("[WARN] Received request for domain %s with method %s but the domain did not match any challenge. Please ensure your are passing the HOST header properly.", r.Host, r.Method)
+			w.Write([]byte("TEST"))
+		}
+	})
+
+	httpServer := &http.Server{
+		Handler: mux,
+	}
+	// Once httpServer is shut down we don't want any lingering
+	// connections, so disable KeepAlives.
+	httpServer.SetKeepAlivesEnabled(false)
+	httpServer.Serve(s.listener)
+	s.done <- true
+}

vendor/github.com/xenolf/lego/acmev2/jws.go

@@ -0,0 +1,138 @@
+package acme
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"fmt"
+	"net/http"
+	"sync"
+
+	"gopkg.in/square/go-jose.v2"
+)
+
+type jws struct {
+	getNonceURL string
+	privKey     crypto.PrivateKey
+	kid         string
+	nonces      nonceManager
+}
+
+// Posts a JWS signed message to the specified URL.
+// It does NOT close the response body, so the caller must
+// do that if no error was returned.
+func (j *jws) post(url string, content []byte) (*http.Response, error) {
+	signedContent, err := j.signContent(url, content)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to sign content -> %s", err.Error())
+	}
+
+	data := bytes.NewBuffer([]byte(signedContent.FullSerialize()))
+	resp, err := httpPost(url, "application/jose+json", data)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to HTTP POST to %s -> %s", url, err.Error())
+	}
+
+	nonce, nonceErr := getNonceFromResponse(resp)
+	if nonceErr == nil {
+		j.nonces.Push(nonce)
+	}
+
+	return resp, nil
+}
+
+func (j *jws) signContent(url string, content []byte) (*jose.JSONWebSignature, error) {
+
+	var alg jose.SignatureAlgorithm
+	switch k := j.privKey.(type) {
+	case *rsa.PrivateKey:
+		alg = jose.RS256
+	case *ecdsa.PrivateKey:
+		if k.Curve == elliptic.P256() {
+			alg = jose.ES256
+		} else if k.Curve == elliptic.P384() {
+			alg = jose.ES384
+		}
+	}
+
+	jsonKey := jose.JSONWebKey{
+		Key:   j.privKey,
+		KeyID: j.kid,
+	}
+
+	signKey := jose.SigningKey{
+		Algorithm: alg,
+		Key:       jsonKey,
+	}
+	options := jose.SignerOptions{
+		NonceSource:  j,
+		ExtraHeaders: make(map[jose.HeaderKey]interface{}),
+	}
+	options.ExtraHeaders["url"] = url
+	if j.kid == "" {
+		options.EmbedJWK = true
+	}
+
+	signer, err := jose.NewSigner(signKey, &options)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to create jose signer -> %s", err.Error())
+	}
+
+	signed, err := signer.Sign(content)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to sign content -> %s", err.Error())
+	}
+	return signed, nil
+}
+
+func (j *jws) Nonce() (string, error) {
+	if nonce, ok := j.nonces.Pop(); ok {
+		return nonce, nil
+	}
+
+	return getNonce(j.getNonceURL)
+}
+
+type nonceManager struct {
+	nonces []string
+	sync.Mutex
+}
+
+func (n *nonceManager) Pop() (string, bool) {
+	n.Lock()
+	defer n.Unlock()
+
+	if len(n.nonces) == 0 {
+		return "", false
+	}
+
+	nonce := n.nonces[len(n.nonces)-1]
+	n.nonces = n.nonces[:len(n.nonces)-1]
+	return nonce, true
+}
+
+func (n *nonceManager) Push(nonce string) {
+	n.Lock()
+	defer n.Unlock()
+	n.nonces = append(n.nonces, nonce)
+}
+
+func getNonce(url string) (string, error) {
+	resp, err := httpHead(url)
+	if err != nil {
+		return "", fmt.Errorf("Failed to get nonce from HTTP HEAD -> %s", err.Error())
+	}
+
+	return getNonceFromResponse(resp)
+}
+
+func getNonceFromResponse(resp *http.Response) (string, error) {
+	nonce := resp.Header.Get("Replay-Nonce")
+	if nonce == "" {
+		return "", fmt.Errorf("Server did not respond with a proper nonce header")
+	}
+
+	return nonce, nil
+}

vendor/github.com/xenolf/lego/acmev2/messages.go

@@ -0,0 +1,104 @@
+package acme
+
+import (
+	"time"
+)
+
+// RegistrationResource represents all important informations about a registration
+// of which the client needs to keep track itself.
+type RegistrationResource struct {
+	Body accountMessage `json:"body,omitempty"`
+	URI  string         `json:"uri,omitempty"`
+}
+
+type directory struct {
+	NewNonceURL   string `json:"newNonce"`
+	NewAccountURL string `json:"newAccount"`
+	NewOrderURL   string `json:"newOrder"`
+	RevokeCertURL string `json:"revokeCert"`
+	KeyChangeURL  string `json:"keyChange"`
+	Meta          struct {
+		TermsOfService          string   `json:"termsOfService"`
+		Website                 string   `json:"website"`
+		CaaIdentities           []string `json:"caaIdentities"`
+		ExternalAccountRequired bool     `json:"externalAccountRequired"`
+	} `json:"meta"`
+}
+
+type accountMessage struct {
+	Status               string   `json:"status,omitempty"`
+	Contact              []string `json:"contact,omitempty"`
+	TermsOfServiceAgreed bool     `json:"termsOfServiceAgreed,omitempty"`
+	Orders               string   `json:"orders,omitempty"`
+	OnlyReturnExisting   bool     `json:"onlyReturnExisting,omitempty"`
+}
+
+type orderResource struct {
+	URL          string   `json:"url,omitempty"`
+	Domains      []string `json:"domains,omitempty"`
+	orderMessage `json:"body,omitempty"`
+}
+
+type orderMessage struct {
+	Status         string       `json:"status,omitempty"`
+	Expires        string       `json:"expires,omitempty"`
+	Identifiers    []identifier `json:"identifiers"`
+	NotBefore      string       `json:"notBefore,omitempty"`
+	NotAfter       string       `json:"notAfter,omitempty"`
+	Authorizations []string     `json:"authorizations,omitempty"`
+	Finalize       string       `json:"finalize,omitempty"`
+	Certificate    string       `json:"certificate,omitempty"`
+}
+
+type authorization struct {
+	Status     string      `json:"status"`
+	Expires    time.Time   `json:"expires"`
+	Identifier identifier  `json:"identifier"`
+	Challenges []challenge `json:"challenges"`
+}
+
+type identifier struct {
+	Type  string `json:"type"`
+	Value string `json:"value"`
+}
+
+type challenge struct {
+	URL              string      `json:"url"`
+	Type             string      `json:"type"`
+	Status           string      `json:"status"`
+	Token            string      `json:"token"`
+	Validated        time.Time   `json:"validated"`
+	KeyAuthorization string      `json:"keyAuthorization"`
+	Error            RemoteError `json:"error"`
+}
+
+type csrMessage struct {
+	Csr string `json:"csr"`
+}
+
+type emptyObjectMessage struct {
+}
+
+type revokeCertMessage struct {
+	Certificate string `json:"certificate"`
+}
+
+type deactivateAuthMessage struct {
+	Status string `jsom:"status"`
+}
+
+// CertificateResource represents a CA issued certificate.
+// PrivateKey, Certificate and IssuerCertificate are all
+// already PEM encoded and can be directly written to disk.
+// Certificate may be a certificate bundle, depending on the
+// options supplied to create it.
+type CertificateResource struct {
+	Domain            string `json:"domain"`
+	CertURL           string `json:"certUrl"`
+	CertStableURL     string `json:"certStableUrl"`
+	AccountRef        string `json:"accountRef,omitempty"`
+	PrivateKey        []byte `json:"-"`
+	Certificate       []byte `json:"-"`
+	IssuerCertificate []byte `json:"-"`
+	CSR               []byte `json:"-"`
+}

vendor/github.com/xenolf/lego/acmev2/pop_challenge.go

@@ -0,0 +1 @@
+package acme

vendor/github.com/xenolf/lego/acmev2/provider.go

@@ -0,0 +1,28 @@
+package acme
+
+import "time"
+
+// ChallengeProvider enables implementing a custom challenge
+// provider. Present presents the solution to a challenge available to
+// be solved. CleanUp will be called by the challenge if Present ends
+// in a non-error state.
+type ChallengeProvider interface {
+	Present(domain, token, keyAuth string) error
+	CleanUp(domain, token, keyAuth string) error
+}
+
+// ChallengeProviderTimeout allows for implementing a
+// ChallengeProvider where an unusually long timeout is required when
+// waiting for an ACME challenge to be satisfied, such as when
+// checking for DNS record progagation. If an implementor of a
+// ChallengeProvider provides a Timeout method, then the return values
+// of the Timeout method will be used when appropriate by the acme
+// package. The interval value is the time between checks.
+//
+// The default values used for timeout and interval are 60 seconds and
+// 2 seconds respectively. These are used when no Timeout method is
+// defined for the ChallengeProvider.
+type ChallengeProviderTimeout interface {
+	ChallengeProvider
+	Timeout() (timeout, interval time.Duration)
+}

vendor/github.com/xenolf/lego/acmev2/utils.go

@@ -0,0 +1,29 @@
+package acme
+
+import (
+	"fmt"
+	"time"
+)
+
+// WaitFor polls the given function 'f', once every 'interval', up to 'timeout'.
+func WaitFor(timeout, interval time.Duration, f func() (bool, error)) error {
+	var lastErr string
+	timeup := time.After(timeout)
+	for {
+		select {
+		case <-timeup:
+			return fmt.Errorf("Time limit exceeded. Last error: %s", lastErr)
+		default:
+		}
+
+		stop, err := f()
+		if stop {
+			return nil
+		}
+		if err != nil {
+			lastErr = err.Error()
+		}
+
+		time.Sleep(interval)
+	}
+}