Upgrading dependencies to include logrus.

vendor/golang.org/x/crypto/acme/acme.go

@@ -0,0 +1,922 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package acme provides an implementation of the
+// Automatic Certificate Management Environment (ACME) spec.
+// See https://tools.ietf.org/html/draft-ietf-acme-acme-02 for details.
+//
+// Most common scenarios will want to use autocert subdirectory instead,
+// which provides automatic access to certificates from Let's Encrypt
+// and any other ACME-based CA.
+//
+// This package is a work in progress and makes no API stability promises.
+package acme
+
+import (
+	"context"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/big"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	// LetsEncryptURL is the Directory endpoint of Let's Encrypt CA.
+	LetsEncryptURL = "https://acme-v01.api.letsencrypt.org/directory"
+
+	// ALPNProto is the ALPN protocol name used by a CA server when validating
+	// tls-alpn-01 challenges.
+	//
+	// Package users must ensure their servers can negotiate the ACME ALPN in
+	// order for tls-alpn-01 challenge verifications to succeed.
+	// See the crypto/tls package's Config.NextProtos field.
+	ALPNProto = "acme-tls/1"
+)
+
+// idPeACMEIdentifierV1 is the OID for the ACME extension for the TLS-ALPN challenge.
+var idPeACMEIdentifierV1 = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 30, 1}
+
+const (
+	maxChainLen = 5       // max depth and breadth of a certificate chain
+	maxCertSize = 1 << 20 // max size of a certificate, in bytes
+
+	// Max number of collected nonces kept in memory.
+	// Expect usual peak of 1 or 2.
+	maxNonces = 100
+)
+
+// Client is an ACME client.
+// The only required field is Key. An example of creating a client with a new key
+// is as follows:
+//
+// 	key, err := rsa.GenerateKey(rand.Reader, 2048)
+// 	if err != nil {
+// 		log.Fatal(err)
+// 	}
+// 	client := &Client{Key: key}
+//
+type Client struct {
+	// Key is the account key used to register with a CA and sign requests.
+	// Key.Public() must return a *rsa.PublicKey or *ecdsa.PublicKey.
+	Key crypto.Signer
+
+	// HTTPClient optionally specifies an HTTP client to use
+	// instead of http.DefaultClient.
+	HTTPClient *http.Client
+
+	// DirectoryURL points to the CA directory endpoint.
+	// If empty, LetsEncryptURL is used.
+	// Mutating this value after a successful call of Client's Discover method
+	// will have no effect.
+	DirectoryURL string
+
+	// RetryBackoff computes the duration after which the nth retry of a failed request
+	// should occur. The value of n for the first call on failure is 1.
+	// The values of r and resp are the request and response of the last failed attempt.
+	// If the returned value is negative or zero, no more retries are done and an error
+	// is returned to the caller of the original method.
+	//
+	// Requests which result in a 4xx client error are not retried,
+	// except for 400 Bad Request due to "bad nonce" errors and 429 Too Many Requests.
+	//
+	// If RetryBackoff is nil, a truncated exponential backoff algorithm
+	// with the ceiling of 10 seconds is used, where each subsequent retry n
+	// is done after either ("Retry-After" + jitter) or (2^n seconds + jitter),
+	// preferring the former if "Retry-After" header is found in the resp.
+	// The jitter is a random value up to 1 second.
+	RetryBackoff func(n int, r *http.Request, resp *http.Response) time.Duration
+
+	dirMu sync.Mutex // guards writes to dir
+	dir   *Directory // cached result of Client's Discover method
+
+	noncesMu sync.Mutex
+	nonces   map[string]struct{} // nonces collected from previous responses
+}
+
+// Discover performs ACME server discovery using c.DirectoryURL.
+//
+// It caches successful result. So, subsequent calls will not result in
+// a network round-trip. This also means mutating c.DirectoryURL after successful call
+// of this method will have no effect.
+func (c *Client) Discover(ctx context.Context) (Directory, error) {
+	c.dirMu.Lock()
+	defer c.dirMu.Unlock()
+	if c.dir != nil {
+		return *c.dir, nil
+	}
+
+	dirURL := c.DirectoryURL
+	if dirURL == "" {
+		dirURL = LetsEncryptURL
+	}
+	res, err := c.get(ctx, dirURL, wantStatus(http.StatusOK))
+	if err != nil {
+		return Directory{}, err
+	}
+	defer res.Body.Close()
+	c.addNonce(res.Header)
+
+	var v struct {
+		Reg    string `json:"new-reg"`
+		Authz  string `json:"new-authz"`
+		Cert   string `json:"new-cert"`
+		Revoke string `json:"revoke-cert"`
+		Meta   struct {
+			Terms   string   `json:"terms-of-service"`
+			Website string   `json:"website"`
+			CAA     []string `json:"caa-identities"`
+		}
+	}
+	if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
+		return Directory{}, err
+	}
+	c.dir = &Directory{
+		RegURL:    v.Reg,
+		AuthzURL:  v.Authz,
+		CertURL:   v.Cert,
+		RevokeURL: v.Revoke,
+		Terms:     v.Meta.Terms,
+		Website:   v.Meta.Website,
+		CAA:       v.Meta.CAA,
+	}
+	return *c.dir, nil
+}
+
+// CreateCert requests a new certificate using the Certificate Signing Request csr encoded in DER format.
+// The exp argument indicates the desired certificate validity duration. CA may issue a certificate
+// with a different duration.
+// If the bundle argument is true, the returned value will also contain the CA (issuer) certificate chain.
+//
+// In the case where CA server does not provide the issued certificate in the response,
+// CreateCert will poll certURL using c.FetchCert, which will result in additional round-trips.
+// In such a scenario, the caller can cancel the polling with ctx.
+//
+// CreateCert returns an error if the CA's response or chain was unreasonably large.
+// Callers are encouraged to parse the returned value to ensure the certificate is valid and has the expected features.
+func (c *Client) CreateCert(ctx context.Context, csr []byte, exp time.Duration, bundle bool) (der [][]byte, certURL string, err error) {
+	if _, err := c.Discover(ctx); err != nil {
+		return nil, "", err
+	}
+
+	req := struct {
+		Resource  string `json:"resource"`
+		CSR       string `json:"csr"`
+		NotBefore string `json:"notBefore,omitempty"`
+		NotAfter  string `json:"notAfter,omitempty"`
+	}{
+		Resource: "new-cert",
+		CSR:      base64.RawURLEncoding.EncodeToString(csr),
+	}
+	now := timeNow()
+	req.NotBefore = now.Format(time.RFC3339)
+	if exp > 0 {
+		req.NotAfter = now.Add(exp).Format(time.RFC3339)
+	}
+
+	res, err := c.post(ctx, c.Key, c.dir.CertURL, req, wantStatus(http.StatusCreated))
+	if err != nil {
+		return nil, "", err
+	}
+	defer res.Body.Close()
+
+	curl := res.Header.Get("Location") // cert permanent URL
+	if res.ContentLength == 0 {
+		// no cert in the body; poll until we get it
+		cert, err := c.FetchCert(ctx, curl, bundle)
+		return cert, curl, err
+	}
+	// slurp issued cert and CA chain, if requested
+	cert, err := c.responseCert(ctx, res, bundle)
+	return cert, curl, err
+}
+
+// FetchCert retrieves already issued certificate from the given url, in DER format.
+// It retries the request until the certificate is successfully retrieved,
+// context is cancelled by the caller or an error response is received.
+//
+// The returned value will also contain the CA (issuer) certificate if the bundle argument is true.
+//
+// FetchCert returns an error if the CA's response or chain was unreasonably large.
+// Callers are encouraged to parse the returned value to ensure the certificate is valid
+// and has expected features.
+func (c *Client) FetchCert(ctx context.Context, url string, bundle bool) ([][]byte, error) {
+	res, err := c.get(ctx, url, wantStatus(http.StatusOK))
+	if err != nil {
+		return nil, err
+	}
+	return c.responseCert(ctx, res, bundle)
+}
+
+// RevokeCert revokes a previously issued certificate cert, provided in DER format.
+//
+// The key argument, used to sign the request, must be authorized
+// to revoke the certificate. It's up to the CA to decide which keys are authorized.
+// For instance, the key pair of the certificate may be authorized.
+// If the key is nil, c.Key is used instead.
+func (c *Client) RevokeCert(ctx context.Context, key crypto.Signer, cert []byte, reason CRLReasonCode) error {
+	if _, err := c.Discover(ctx); err != nil {
+		return err
+	}
+
+	body := &struct {
+		Resource string `json:"resource"`
+		Cert     string `json:"certificate"`
+		Reason   int    `json:"reason"`
+	}{
+		Resource: "revoke-cert",
+		Cert:     base64.RawURLEncoding.EncodeToString(cert),
+		Reason:   int(reason),
+	}
+	if key == nil {
+		key = c.Key
+	}
+	res, err := c.post(ctx, key, c.dir.RevokeURL, body, wantStatus(http.StatusOK))
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	return nil
+}
+
+// AcceptTOS always returns true to indicate the acceptance of a CA's Terms of Service
+// during account registration. See Register method of Client for more details.
+func AcceptTOS(tosURL string) bool { return true }
+
+// Register creates a new account registration by following the "new-reg" flow.
+// It returns the registered account. The account is not modified.
+//
+// The registration may require the caller to agree to the CA's Terms of Service (TOS).
+// If so, and the account has not indicated the acceptance of the terms (see Account for details),
+// Register calls prompt with a TOS URL provided by the CA. Prompt should report
+// whether the caller agrees to the terms. To always accept the terms, the caller can use AcceptTOS.
+func (c *Client) Register(ctx context.Context, a *Account, prompt func(tosURL string) bool) (*Account, error) {
+	if _, err := c.Discover(ctx); err != nil {
+		return nil, err
+	}
+
+	var err error
+	if a, err = c.doReg(ctx, c.dir.RegURL, "new-reg", a); err != nil {
+		return nil, err
+	}
+	var accept bool
+	if a.CurrentTerms != "" && a.CurrentTerms != a.AgreedTerms {
+		accept = prompt(a.CurrentTerms)
+	}
+	if accept {
+		a.AgreedTerms = a.CurrentTerms
+		a, err = c.UpdateReg(ctx, a)
+	}
+	return a, err
+}
+
+// GetReg retrieves an existing registration.
+// The url argument is an Account URI.
+func (c *Client) GetReg(ctx context.Context, url string) (*Account, error) {
+	a, err := c.doReg(ctx, url, "reg", nil)
+	if err != nil {
+		return nil, err
+	}
+	a.URI = url
+	return a, nil
+}
+
+// UpdateReg updates an existing registration.
+// It returns an updated account copy. The provided account is not modified.
+func (c *Client) UpdateReg(ctx context.Context, a *Account) (*Account, error) {
+	uri := a.URI
+	a, err := c.doReg(ctx, uri, "reg", a)
+	if err != nil {
+		return nil, err
+	}
+	a.URI = uri
+	return a, nil
+}
+
+// Authorize performs the initial step in an authorization flow.
+// The caller will then need to choose from and perform a set of returned
+// challenges using c.Accept in order to successfully complete authorization.
+//
+// If an authorization has been previously granted, the CA may return
+// a valid authorization (Authorization.Status is StatusValid). If so, the caller
+// need not fulfill any challenge and can proceed to requesting a certificate.
+func (c *Client) Authorize(ctx context.Context, domain string) (*Authorization, error) {
+	if _, err := c.Discover(ctx); err != nil {
+		return nil, err
+	}
+
+	type authzID struct {
+		Type  string `json:"type"`
+		Value string `json:"value"`
+	}
+	req := struct {
+		Resource   string  `json:"resource"`
+		Identifier authzID `json:"identifier"`
+	}{
+		Resource:   "new-authz",
+		Identifier: authzID{Type: "dns", Value: domain},
+	}
+	res, err := c.post(ctx, c.Key, c.dir.AuthzURL, req, wantStatus(http.StatusCreated))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	var v wireAuthz
+	if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
+		return nil, fmt.Errorf("acme: invalid response: %v", err)
+	}
+	if v.Status != StatusPending && v.Status != StatusValid {
+		return nil, fmt.Errorf("acme: unexpected status: %s", v.Status)
+	}
+	return v.authorization(res.Header.Get("Location")), nil
+}
+
+// GetAuthorization retrieves an authorization identified by the given URL.
+//
+// If a caller needs to poll an authorization until its status is final,
+// see the WaitAuthorization method.
+func (c *Client) GetAuthorization(ctx context.Context, url string) (*Authorization, error) {
+	res, err := c.get(ctx, url, wantStatus(http.StatusOK, http.StatusAccepted))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	var v wireAuthz
+	if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
+		return nil, fmt.Errorf("acme: invalid response: %v", err)
+	}
+	return v.authorization(url), nil
+}
+
+// RevokeAuthorization relinquishes an existing authorization identified
+// by the given URL.
+// The url argument is an Authorization.URI value.
+//
+// If successful, the caller will be required to obtain a new authorization
+// using the Authorize method before being able to request a new certificate
+// for the domain associated with the authorization.
+//
+// It does not revoke existing certificates.
+func (c *Client) RevokeAuthorization(ctx context.Context, url string) error {
+	req := struct {
+		Resource string `json:"resource"`
+		Status   string `json:"status"`
+		Delete   bool   `json:"delete"`
+	}{
+		Resource: "authz",
+		Status:   "deactivated",
+		Delete:   true,
+	}
+	res, err := c.post(ctx, c.Key, url, req, wantStatus(http.StatusOK))
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	return nil
+}
+
+// WaitAuthorization polls an authorization at the given URL
+// until it is in one of the final states, StatusValid or StatusInvalid,
+// the ACME CA responded with a 4xx error code, or the context is done.
+//
+// It returns a non-nil Authorization only if its Status is StatusValid.
+// In all other cases WaitAuthorization returns an error.
+// If the Status is StatusInvalid, the returned error is of type *AuthorizationError.
+func (c *Client) WaitAuthorization(ctx context.Context, url string) (*Authorization, error) {
+	for {
+		res, err := c.get(ctx, url, wantStatus(http.StatusOK, http.StatusAccepted))
+		if err != nil {
+			return nil, err
+		}
+
+		var raw wireAuthz
+		err = json.NewDecoder(res.Body).Decode(&raw)
+		res.Body.Close()
+		switch {
+		case err != nil:
+			// Skip and retry.
+		case raw.Status == StatusValid:
+			return raw.authorization(url), nil
+		case raw.Status == StatusInvalid:
+			return nil, raw.error(url)
+		}
+
+		// Exponential backoff is implemented in c.get above.
+		// This is just to prevent continuously hitting the CA
+		// while waiting for a final authorization status.
+		d := retryAfter(res.Header.Get("Retry-After"))
+		if d == 0 {
+			// Given that the fastest challenges TLS-SNI and HTTP-01
+			// require a CA to make at least 1 network round trip
+			// and most likely persist a challenge state,
+			// this default delay seems reasonable.
+			d = time.Second
+		}
+		t := time.NewTimer(d)
+		select {
+		case <-ctx.Done():
+			t.Stop()
+			return nil, ctx.Err()
+		case <-t.C:
+			// Retry.
+		}
+	}
+}
+
+// GetChallenge retrieves the current status of an challenge.
+//
+// A client typically polls a challenge status using this method.
+func (c *Client) GetChallenge(ctx context.Context, url string) (*Challenge, error) {
+	res, err := c.get(ctx, url, wantStatus(http.StatusOK, http.StatusAccepted))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	v := wireChallenge{URI: url}
+	if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
+		return nil, fmt.Errorf("acme: invalid response: %v", err)
+	}
+	return v.challenge(), nil
+}
+
+// Accept informs the server that the client accepts one of its challenges
+// previously obtained with c.Authorize.
+//
+// The server will then perform the validation asynchronously.
+func (c *Client) Accept(ctx context.Context, chal *Challenge) (*Challenge, error) {
+	auth, err := keyAuth(c.Key.Public(), chal.Token)
+	if err != nil {
+		return nil, err
+	}
+
+	req := struct {
+		Resource string `json:"resource"`
+		Type     string `json:"type"`
+		Auth     string `json:"keyAuthorization"`
+	}{
+		Resource: "challenge",
+		Type:     chal.Type,
+		Auth:     auth,
+	}
+	res, err := c.post(ctx, c.Key, chal.URI, req, wantStatus(
+		http.StatusOK,       // according to the spec
+		http.StatusAccepted, // Let's Encrypt: see https://goo.gl/WsJ7VT (acme-divergences.md)
+	))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	var v wireChallenge
+	if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
+		return nil, fmt.Errorf("acme: invalid response: %v", err)
+	}
+	return v.challenge(), nil
+}
+
+// DNS01ChallengeRecord returns a DNS record value for a dns-01 challenge response.
+// A TXT record containing the returned value must be provisioned under
+// "_acme-challenge" name of the domain being validated.
+//
+// The token argument is a Challenge.Token value.
+func (c *Client) DNS01ChallengeRecord(token string) (string, error) {
+	ka, err := keyAuth(c.Key.Public(), token)
+	if err != nil {
+		return "", err
+	}
+	b := sha256.Sum256([]byte(ka))
+	return base64.RawURLEncoding.EncodeToString(b[:]), nil
+}
+
+// HTTP01ChallengeResponse returns the response for an http-01 challenge.
+// Servers should respond with the value to HTTP requests at the URL path
+// provided by HTTP01ChallengePath to validate the challenge and prove control
+// over a domain name.
+//
+// The token argument is a Challenge.Token value.
+func (c *Client) HTTP01ChallengeResponse(token string) (string, error) {
+	return keyAuth(c.Key.Public(), token)
+}
+
+// HTTP01ChallengePath returns the URL path at which the response for an http-01 challenge
+// should be provided by the servers.
+// The response value can be obtained with HTTP01ChallengeResponse.
+//
+// The token argument is a Challenge.Token value.
+func (c *Client) HTTP01ChallengePath(token string) string {
+	return "/.well-known/acme-challenge/" + token
+}
+
+// TLSSNI01ChallengeCert creates a certificate for TLS-SNI-01 challenge response.
+// Servers can present the certificate to validate the challenge and prove control
+// over a domain name.
+//
+// The implementation is incomplete in that the returned value is a single certificate,
+// computed only for Z0 of the key authorization. ACME CAs are expected to update
+// their implementations to use the newer version, TLS-SNI-02.
+// For more details on TLS-SNI-01 see https://tools.ietf.org/html/draft-ietf-acme-acme-01#section-7.3.
+//
+// The token argument is a Challenge.Token value.
+// If a WithKey option is provided, its private part signs the returned cert,
+// and the public part is used to specify the signee.
+// If no WithKey option is provided, a new ECDSA key is generated using P-256 curve.
+//
+// The returned certificate is valid for the next 24 hours and must be presented only when
+// the server name of the TLS ClientHello matches exactly the returned name value.
+func (c *Client) TLSSNI01ChallengeCert(token string, opt ...CertOption) (cert tls.Certificate, name string, err error) {
+	ka, err := keyAuth(c.Key.Public(), token)
+	if err != nil {
+		return tls.Certificate{}, "", err
+	}
+	b := sha256.Sum256([]byte(ka))
+	h := hex.EncodeToString(b[:])
+	name = fmt.Sprintf("%s.%s.acme.invalid", h[:32], h[32:])
+	cert, err = tlsChallengeCert([]string{name}, opt)
+	if err != nil {
+		return tls.Certificate{}, "", err
+	}
+	return cert, name, nil
+}
+
+// TLSSNI02ChallengeCert creates a certificate for TLS-SNI-02 challenge response.
+// Servers can present the certificate to validate the challenge and prove control
+// over a domain name. For more details on TLS-SNI-02 see
+// https://tools.ietf.org/html/draft-ietf-acme-acme-03#section-7.3.
+//
+// The token argument is a Challenge.Token value.
+// If a WithKey option is provided, its private part signs the returned cert,
+// and the public part is used to specify the signee.
+// If no WithKey option is provided, a new ECDSA key is generated using P-256 curve.
+//
+// The returned certificate is valid for the next 24 hours and must be presented only when
+// the server name in the TLS ClientHello matches exactly the returned name value.
+func (c *Client) TLSSNI02ChallengeCert(token string, opt ...CertOption) (cert tls.Certificate, name string, err error) {
+	b := sha256.Sum256([]byte(token))
+	h := hex.EncodeToString(b[:])
+	sanA := fmt.Sprintf("%s.%s.token.acme.invalid", h[:32], h[32:])
+
+	ka, err := keyAuth(c.Key.Public(), token)
+	if err != nil {
+		return tls.Certificate{}, "", err
+	}
+	b = sha256.Sum256([]byte(ka))
+	h = hex.EncodeToString(b[:])
+	sanB := fmt.Sprintf("%s.%s.ka.acme.invalid", h[:32], h[32:])
+
+	cert, err = tlsChallengeCert([]string{sanA, sanB}, opt)
+	if err != nil {
+		return tls.Certificate{}, "", err
+	}
+	return cert, sanA, nil
+}
+
+// TLSALPN01ChallengeCert creates a certificate for TLS-ALPN-01 challenge response.
+// Servers can present the certificate to validate the challenge and prove control
+// over a domain name. For more details on TLS-ALPN-01 see
+// https://tools.ietf.org/html/draft-shoemaker-acme-tls-alpn-00#section-3
+//
+// The token argument is a Challenge.Token value.
+// If a WithKey option is provided, its private part signs the returned cert,
+// and the public part is used to specify the signee.
+// If no WithKey option is provided, a new ECDSA key is generated using P-256 curve.
+//
+// The returned certificate is valid for the next 24 hours and must be presented only when
+// the server name in the TLS ClientHello matches the domain, and the special acme-tls/1 ALPN protocol
+// has been specified.
+func (c *Client) TLSALPN01ChallengeCert(token, domain string, opt ...CertOption) (cert tls.Certificate, err error) {
+	ka, err := keyAuth(c.Key.Public(), token)
+	if err != nil {
+		return tls.Certificate{}, err
+	}
+	shasum := sha256.Sum256([]byte(ka))
+	extValue, err := asn1.Marshal(shasum[:])
+	if err != nil {
+		return tls.Certificate{}, err
+	}
+	acmeExtension := pkix.Extension{
+		Id:       idPeACMEIdentifierV1,
+		Critical: true,
+		Value:    extValue,
+	}
+
+	tmpl := defaultTLSChallengeCertTemplate()
+
+	var newOpt []CertOption
+	for _, o := range opt {
+		switch o := o.(type) {
+		case *certOptTemplate:
+			t := *(*x509.Certificate)(o) // shallow copy is ok
+			tmpl = &t
+		default:
+			newOpt = append(newOpt, o)
+		}
+	}
+	tmpl.ExtraExtensions = append(tmpl.ExtraExtensions, acmeExtension)
+	newOpt = append(newOpt, WithTemplate(tmpl))
+	return tlsChallengeCert([]string{domain}, newOpt)
+}
+
+// doReg sends all types of registration requests.
+// The type of request is identified by typ argument, which is a "resource"
+// in the ACME spec terms.
+//
+// A non-nil acct argument indicates whether the intention is to mutate data
+// of the Account. Only Contact and Agreement of its fields are used
+// in such cases.
+func (c *Client) doReg(ctx context.Context, url string, typ string, acct *Account) (*Account, error) {
+	req := struct {
+		Resource  string   `json:"resource"`
+		Contact   []string `json:"contact,omitempty"`
+		Agreement string   `json:"agreement,omitempty"`
+	}{
+		Resource: typ,
+	}
+	if acct != nil {
+		req.Contact = acct.Contact
+		req.Agreement = acct.AgreedTerms
+	}
+	res, err := c.post(ctx, c.Key, url, req, wantStatus(
+		http.StatusOK,       // updates and deletes
+		http.StatusCreated,  // new account creation
+		http.StatusAccepted, // Let's Encrypt divergent implementation
+	))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	var v struct {
+		Contact        []string
+		Agreement      string
+		Authorizations string
+		Certificates   string
+	}
+	if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
+		return nil, fmt.Errorf("acme: invalid response: %v", err)
+	}
+	var tos string
+	if v := linkHeader(res.Header, "terms-of-service"); len(v) > 0 {
+		tos = v[0]
+	}
+	var authz string
+	if v := linkHeader(res.Header, "next"); len(v) > 0 {
+		authz = v[0]
+	}
+	return &Account{
+		URI:            res.Header.Get("Location"),
+		Contact:        v.Contact,
+		AgreedTerms:    v.Agreement,
+		CurrentTerms:   tos,
+		Authz:          authz,
+		Authorizations: v.Authorizations,
+		Certificates:   v.Certificates,
+	}, nil
+}
+
+// popNonce returns a nonce value previously stored with c.addNonce
+// or fetches a fresh one from the given URL.
+func (c *Client) popNonce(ctx context.Context, url string) (string, error) {
+	c.noncesMu.Lock()
+	defer c.noncesMu.Unlock()
+	if len(c.nonces) == 0 {
+		return c.fetchNonce(ctx, url)
+	}
+	var nonce string
+	for nonce = range c.nonces {
+		delete(c.nonces, nonce)
+		break
+	}
+	return nonce, nil
+}
+
+// clearNonces clears any stored nonces
+func (c *Client) clearNonces() {
+	c.noncesMu.Lock()
+	defer c.noncesMu.Unlock()
+	c.nonces = make(map[string]struct{})
+}
+
+// addNonce stores a nonce value found in h (if any) for future use.
+func (c *Client) addNonce(h http.Header) {
+	v := nonceFromHeader(h)
+	if v == "" {
+		return
+	}
+	c.noncesMu.Lock()
+	defer c.noncesMu.Unlock()
+	if len(c.nonces) >= maxNonces {
+		return
+	}
+	if c.nonces == nil {
+		c.nonces = make(map[string]struct{})
+	}
+	c.nonces[v] = struct{}{}
+}
+
+func (c *Client) fetchNonce(ctx context.Context, url string) (string, error) {
+	r, err := http.NewRequest("HEAD", url, nil)
+	if err != nil {
+		return "", err
+	}
+	resp, err := c.doNoRetry(ctx, r)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	nonce := nonceFromHeader(resp.Header)
+	if nonce == "" {
+		if resp.StatusCode > 299 {
+			return "", responseError(resp)
+		}
+		return "", errors.New("acme: nonce not found")
+	}
+	return nonce, nil
+}
+
+func nonceFromHeader(h http.Header) string {
+	return h.Get("Replay-Nonce")
+}
+
+func (c *Client) responseCert(ctx context.Context, res *http.Response, bundle bool) ([][]byte, error) {
+	b, err := ioutil.ReadAll(io.LimitReader(res.Body, maxCertSize+1))
+	if err != nil {
+		return nil, fmt.Errorf("acme: response stream: %v", err)
+	}
+	if len(b) > maxCertSize {
+		return nil, errors.New("acme: certificate is too big")
+	}
+	cert := [][]byte{b}
+	if !bundle {
+		return cert, nil
+	}
+
+	// Append CA chain cert(s).
+	// At least one is required according to the spec:
+	// https://tools.ietf.org/html/draft-ietf-acme-acme-03#section-6.3.1
+	up := linkHeader(res.Header, "up")
+	if len(up) == 0 {
+		return nil, errors.New("acme: rel=up link not found")
+	}
+	if len(up) > maxChainLen {
+		return nil, errors.New("acme: rel=up link is too large")
+	}
+	for _, url := range up {
+		cc, err := c.chainCert(ctx, url, 0)
+		if err != nil {
+			return nil, err
+		}
+		cert = append(cert, cc...)
+	}
+	return cert, nil
+}
+
+// chainCert fetches CA certificate chain recursively by following "up" links.
+// Each recursive call increments the depth by 1, resulting in an error
+// if the recursion level reaches maxChainLen.
+//
+// First chainCert call starts with depth of 0.
+func (c *Client) chainCert(ctx context.Context, url string, depth int) ([][]byte, error) {
+	if depth >= maxChainLen {
+		return nil, errors.New("acme: certificate chain is too deep")
+	}
+
+	res, err := c.get(ctx, url, wantStatus(http.StatusOK))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	b, err := ioutil.ReadAll(io.LimitReader(res.Body, maxCertSize+1))
+	if err != nil {
+		return nil, err
+	}
+	if len(b) > maxCertSize {
+		return nil, errors.New("acme: certificate is too big")
+	}
+	chain := [][]byte{b}
+
+	uplink := linkHeader(res.Header, "up")
+	if len(uplink) > maxChainLen {
+		return nil, errors.New("acme: certificate chain is too large")
+	}
+	for _, up := range uplink {
+		cc, err := c.chainCert(ctx, up, depth+1)
+		if err != nil {
+			return nil, err
+		}
+		chain = append(chain, cc...)
+	}
+
+	return chain, nil
+}
+
+// linkHeader returns URI-Reference values of all Link headers
+// with relation-type rel.
+// See https://tools.ietf.org/html/rfc5988#section-5 for details.
+func linkHeader(h http.Header, rel string) []string {
+	var links []string
+	for _, v := range h["Link"] {
+		parts := strings.Split(v, ";")
+		for _, p := range parts {
+			p = strings.TrimSpace(p)
+			if !strings.HasPrefix(p, "rel=") {
+				continue
+			}
+			if v := strings.Trim(p[4:], `"`); v == rel {
+				links = append(links, strings.Trim(parts[0], "<>"))
+			}
+		}
+	}
+	return links
+}
+
+// keyAuth generates a key authorization string for a given token.
+func keyAuth(pub crypto.PublicKey, token string) (string, error) {
+	th, err := JWKThumbprint(pub)
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%s.%s", token, th), nil
+}
+
+// defaultTLSChallengeCertTemplate is a template used to create challenge certs for TLS challenges.
+func defaultTLSChallengeCertTemplate() *x509.Certificate {
+	return &x509.Certificate{
+		SerialNumber:          big.NewInt(1),
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().Add(24 * time.Hour),
+		BasicConstraintsValid: true,
+		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+	}
+}
+
+// tlsChallengeCert creates a temporary certificate for TLS-SNI challenges
+// with the given SANs and auto-generated public/private key pair.
+// The Subject Common Name is set to the first SAN to aid debugging.
+// To create a cert with a custom key pair, specify WithKey option.
+func tlsChallengeCert(san []string, opt []CertOption) (tls.Certificate, error) {
+	var key crypto.Signer
+	tmpl := defaultTLSChallengeCertTemplate()
+	for _, o := range opt {
+		switch o := o.(type) {
+		case *certOptKey:
+			if key != nil {
+				return tls.Certificate{}, errors.New("acme: duplicate key option")
+			}
+			key = o.key
+		case *certOptTemplate:
+			t := *(*x509.Certificate)(o) // shallow copy is ok
+			tmpl = &t
+		default:
+			// package's fault, if we let this happen:
+			panic(fmt.Sprintf("unsupported option type %T", o))
+		}
+	}
+	if key == nil {
+		var err error
+		if key, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader); err != nil {
+			return tls.Certificate{}, err
+		}
+	}
+	tmpl.DNSNames = san
+	if len(san) > 0 {
+		tmpl.Subject.CommonName = san[0]
+	}
+
+	der, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, key.Public(), key)
+	if err != nil {
+		return tls.Certificate{}, err
+	}
+	return tls.Certificate{
+		Certificate: [][]byte{der},
+		PrivateKey:  key,
+	}, nil
+}
+
+// encodePEM returns b encoded as PEM with block of type typ.
+func encodePEM(typ string, b []byte) []byte {
+	pb := &pem.Block{Type: typ, Bytes: b}
+	return pem.EncodeToMemory(pb)
+}
+
+// timeNow is useful for testing for fixed current time.
+var timeNow = time.Now

vendor/golang.org/x/crypto/acme/autocert/cache.go

@@ -0,0 +1,130 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package autocert
+
+import (
+	"context"
+	"errors"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// ErrCacheMiss is returned when a certificate is not found in cache.
+var ErrCacheMiss = errors.New("acme/autocert: certificate cache miss")
+
+// Cache is used by Manager to store and retrieve previously obtained certificates
+// and other account data as opaque blobs.
+//
+// Cache implementations should not rely on the key naming pattern. Keys can
+// include any printable ASCII characters, except the following: \/:*?"<>|
+type Cache interface {
+	// Get returns a certificate data for the specified key.
+	// If there's no such key, Get returns ErrCacheMiss.
+	Get(ctx context.Context, key string) ([]byte, error)
+
+	// Put stores the data in the cache under the specified key.
+	// Underlying implementations may use any data storage format,
+	// as long as the reverse operation, Get, results in the original data.
+	Put(ctx context.Context, key string, data []byte) error
+
+	// Delete removes a certificate data from the cache under the specified key.
+	// If there's no such key in the cache, Delete returns nil.
+	Delete(ctx context.Context, key string) error
+}
+
+// DirCache implements Cache using a directory on the local filesystem.
+// If the directory does not exist, it will be created with 0700 permissions.
+type DirCache string
+
+// Get reads a certificate data from the specified file name.
+func (d DirCache) Get(ctx context.Context, name string) ([]byte, error) {
+	name = filepath.Join(string(d), name)
+	var (
+		data []byte
+		err  error
+		done = make(chan struct{})
+	)
+	go func() {
+		data, err = ioutil.ReadFile(name)
+		close(done)
+	}()
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case <-done:
+	}
+	if os.IsNotExist(err) {
+		return nil, ErrCacheMiss
+	}
+	return data, err
+}
+
+// Put writes the certificate data to the specified file name.
+// The file will be created with 0600 permissions.
+func (d DirCache) Put(ctx context.Context, name string, data []byte) error {
+	if err := os.MkdirAll(string(d), 0700); err != nil {
+		return err
+	}
+
+	done := make(chan struct{})
+	var err error
+	go func() {
+		defer close(done)
+		var tmp string
+		if tmp, err = d.writeTempFile(name, data); err != nil {
+			return
+		}
+		select {
+		case <-ctx.Done():
+			// Don't overwrite the file if the context was canceled.
+		default:
+			newName := filepath.Join(string(d), name)
+			err = os.Rename(tmp, newName)
+		}
+	}()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-done:
+	}
+	return err
+}
+
+// Delete removes the specified file name.
+func (d DirCache) Delete(ctx context.Context, name string) error {
+	name = filepath.Join(string(d), name)
+	var (
+		err  error
+		done = make(chan struct{})
+	)
+	go func() {
+		err = os.Remove(name)
+		close(done)
+	}()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-done:
+	}
+	if err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
+}
+
+// writeTempFile writes b to a temporary file, closes the file and returns its path.
+func (d DirCache) writeTempFile(prefix string, b []byte) (string, error) {
+	// TempFile uses 0600 permissions
+	f, err := ioutil.TempFile(string(d), prefix)
+	if err != nil {
+		return "", err
+	}
+	if _, err := f.Write(b); err != nil {
+		f.Close()
+		return "", err
+	}
+	return f.Name(), f.Close()
+}

vendor/golang.org/x/crypto/acme/autocert/cache_test.go

@@ -0,0 +1,58 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package autocert
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+// make sure DirCache satisfies Cache interface
+var _ Cache = DirCache("/")
+
+func TestDirCache(t *testing.T) {
+	dir, err := ioutil.TempDir("", "autocert")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+	dir = filepath.Join(dir, "certs") // a nonexistent dir
+	cache := DirCache(dir)
+	ctx := context.Background()
+
+	// test cache miss
+	if _, err := cache.Get(ctx, "nonexistent"); err != ErrCacheMiss {
+		t.Errorf("get: %v; want ErrCacheMiss", err)
+	}
+
+	// test put/get
+	b1 := []byte{1}
+	if err := cache.Put(ctx, "dummy", b1); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+	b2, err := cache.Get(ctx, "dummy")
+	if err != nil {
+		t.Fatalf("get: %v", err)
+	}
+	if !reflect.DeepEqual(b1, b2) {
+		t.Errorf("b1 = %v; want %v", b1, b2)
+	}
+	name := filepath.Join(dir, "dummy")
+	if _, err := os.Stat(name); err != nil {
+		t.Error(err)
+	}
+
+	// test delete
+	if err := cache.Delete(ctx, "dummy"); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+	if _, err := cache.Get(ctx, "dummy"); err != ErrCacheMiss {
+		t.Errorf("get: %v; want ErrCacheMiss", err)
+	}
+}

vendor/golang.org/x/crypto/acme/autocert/example_test.go

@@ -0,0 +1,34 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package autocert_test
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"golang.org/x/crypto/acme/autocert"
+)
+
+func ExampleNewListener() {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "Hello, TLS user! Your config: %+v", r.TLS)
+	})
+	log.Fatal(http.Serve(autocert.NewListener("example.com"), mux))
+}
+
+func ExampleManager() {
+	m := &autocert.Manager{
+		Cache:      autocert.DirCache("secret-dir"),
+		Prompt:     autocert.AcceptTOS,
+		HostPolicy: autocert.HostWhitelist("example.org", "www.example.org"),
+	}
+	s := &http.Server{
+		Addr:      ":https",
+		TLSConfig: m.TLSConfig(),
+	}
+	s.ListenAndServeTLS("", "")
+}

vendor/golang.org/x/crypto/acme/autocert/internal/acmetest/ca.go

@@ -0,0 +1,416 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package acmetest provides types for testing acme and autocert packages.
+//
+// TODO: Consider moving this to x/crypto/acme/internal/acmetest for acme tests as well.
+package acmetest
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"math/big"
+	"net/http"
+	"net/http/httptest"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+)
+
+// CAServer is a simple test server which implements ACME spec bits needed for testing.
+type CAServer struct {
+	URL   string         // server URL after it has been started
+	Roots *x509.CertPool // CA root certificates; initialized in NewCAServer
+
+	rootKey      crypto.Signer
+	rootCert     []byte // DER encoding
+	rootTemplate *x509.Certificate
+
+	server           *httptest.Server
+	challengeTypes   []string // supported challenge types
+	domainsWhitelist []string // only these domains are valid for issuing, unless empty
+
+	mu             sync.Mutex
+	certCount      int                       // number of issued certs
+	domainAddr     map[string]string         // domain name to addr:port resolution
+	authorizations map[string]*authorization // keyed by domain name
+	errors         []error                   // encountered client errors
+}
+
+// NewCAServer creates a new ACME test server and starts serving requests.
+// The returned CAServer issues certs signed with the CA roots
+// available in the Roots field.
+//
+// The challengeTypes argument defines the supported ACME challenge types
+// sent to a client in a response for a domain authorization.
+// If domainsWhitelist is non-empty, the certs will be issued only for the specified
+// list of domains. Otherwise, any domain name is allowed.
+func NewCAServer(challengeTypes []string, domainsWhitelist []string) *CAServer {
+	var whitelist []string
+	for _, name := range domainsWhitelist {
+		whitelist = append(whitelist, name)
+	}
+	sort.Strings(whitelist)
+	ca := &CAServer{
+		challengeTypes:   challengeTypes,
+		domainsWhitelist: whitelist,
+		domainAddr:       make(map[string]string),
+		authorizations:   make(map[string]*authorization),
+	}
+
+	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		panic(fmt.Sprintf("ecdsa.GenerateKey: %v", err))
+	}
+	tmpl := &x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			Organization: []string{"Test Acme Co"},
+			CommonName:   "Root CA",
+		},
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().Add(365 * 24 * time.Hour),
+		KeyUsage:              x509.KeyUsageCertSign,
+		BasicConstraintsValid: true,
+		IsCA: true,
+	}
+	der, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, &key.PublicKey, key)
+	if err != nil {
+		panic(fmt.Sprintf("x509.CreateCertificate: %v", err))
+	}
+	cert, err := x509.ParseCertificate(der)
+	if err != nil {
+		panic(fmt.Sprintf("x509.ParseCertificate: %v", err))
+	}
+	ca.Roots = x509.NewCertPool()
+	ca.Roots.AddCert(cert)
+	ca.rootKey = key
+	ca.rootCert = der
+	ca.rootTemplate = tmpl
+
+	ca.server = httptest.NewServer(http.HandlerFunc(ca.handle))
+	ca.URL = ca.server.URL
+	return ca
+}
+
+// Close shuts down the server and blocks until all outstanding
+// requests on this server have completed.
+func (ca *CAServer) Close() {
+	ca.server.Close()
+}
+
+// Errors returns all client errors.
+func (ca *CAServer) Errors() []error {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	return ca.errors
+}
+
+// Resolve adds a domain to address resolution for the ca to dial to
+// when validating challenges for the domain authorization.
+func (ca *CAServer) Resolve(domain, addr string) {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	ca.domainAddr[domain] = addr
+}
+
+type discovery struct {
+	NewReg   string `json:"new-reg"`
+	NewAuthz string `json:"new-authz"`
+	NewCert  string `json:"new-cert"`
+}
+
+type challenge struct {
+	URI   string `json:"uri"`
+	Type  string `json:"type"`
+	Token string `json:"token"`
+}
+
+type authorization struct {
+	Status     string      `json:"status"`
+	Challenges []challenge `json:"challenges"`
+
+	id     int
+	domain string
+}
+
+func (ca *CAServer) handle(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Replay-Nonce", "nonce")
+	if r.Method == "HEAD" {
+		// a nonce request
+		return
+	}
+
+	// TODO: Verify nonce header for all POST requests.
+
+	switch {
+	default:
+		err := fmt.Errorf("unrecognized r.URL.Path: %s", r.URL.Path)
+		ca.addError(err)
+		http.Error(w, err.Error(), http.StatusBadRequest)
+
+	// Discovery request.
+	case r.URL.Path == "/":
+		resp := &discovery{
+			NewReg:   ca.serverURL("/new-reg"),
+			NewAuthz: ca.serverURL("/new-authz"),
+			NewCert:  ca.serverURL("/new-cert"),
+		}
+		if err := json.NewEncoder(w).Encode(resp); err != nil {
+			panic(fmt.Sprintf("discovery response: %v", err))
+		}
+
+	// Client key registration request.
+	case r.URL.Path == "/new-reg":
+		// TODO: Check the user account key against a ca.accountKeys?
+		w.Write([]byte("{}"))
+
+	// Domain authorization request.
+	case r.URL.Path == "/new-authz":
+		var req struct {
+			Identifier struct{ Value string }
+		}
+		if err := decodePayload(&req, r.Body); err != nil {
+			ca.addError(err)
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		ca.mu.Lock()
+		defer ca.mu.Unlock()
+		authz, ok := ca.authorizations[req.Identifier.Value]
+		if !ok {
+			authz = &authorization{
+				domain: req.Identifier.Value,
+				Status: "pending",
+			}
+			for _, typ := range ca.challengeTypes {
+				authz.Challenges = append(authz.Challenges, challenge{
+					Type:  typ,
+					URI:   ca.serverURL("/challenge/%s/%s", typ, authz.domain),
+					Token: challengeToken(authz.domain, typ),
+				})
+			}
+			ca.authorizations[authz.domain] = authz
+		}
+		w.Header().Set("Location", ca.serverURL("/authz/%s", authz.domain))
+		w.WriteHeader(http.StatusCreated)
+		if err := json.NewEncoder(w).Encode(authz); err != nil {
+			panic(fmt.Sprintf("new authz response: %v", err))
+		}
+
+	// Accept tls-alpn-01 challenge type requests.
+	// TODO: Add http-01 and dns-01 handlers.
+	case strings.HasPrefix(r.URL.Path, "/challenge/tls-alpn-01/"):
+		domain := strings.TrimPrefix(r.URL.Path, "/challenge/tls-alpn-01/")
+		ca.mu.Lock()
+		defer ca.mu.Unlock()
+		if _, ok := ca.authorizations[domain]; !ok {
+			err := fmt.Errorf("challenge accept: no authz for %q", domain)
+			ca.addError(err)
+			http.Error(w, err.Error(), http.StatusNotFound)
+			return
+		}
+		go func(domain string) {
+			err := ca.verifyALPNChallenge(domain)
+			ca.mu.Lock()
+			defer ca.mu.Unlock()
+			authz := ca.authorizations[domain]
+			if err != nil {
+				authz.Status = "invalid"
+				return
+			}
+			authz.Status = "valid"
+
+		}(domain)
+		w.Write([]byte("{}"))
+
+	// Get authorization status requests.
+	case strings.HasPrefix(r.URL.Path, "/authz/"):
+		domain := strings.TrimPrefix(r.URL.Path, "/authz/")
+		ca.mu.Lock()
+		defer ca.mu.Unlock()
+		authz, ok := ca.authorizations[domain]
+		if !ok {
+			http.Error(w, fmt.Sprintf("no authz for %q", domain), http.StatusNotFound)
+			return
+		}
+		if err := json.NewEncoder(w).Encode(authz); err != nil {
+			panic(fmt.Sprintf("get authz for %q response: %v", domain, err))
+		}
+
+	// Cert issuance request.
+	case r.URL.Path == "/new-cert":
+		var req struct {
+			CSR string `json:"csr"`
+		}
+		decodePayload(&req, r.Body)
+		b, _ := base64.RawURLEncoding.DecodeString(req.CSR)
+		csr, err := x509.ParseCertificateRequest(b)
+		if err != nil {
+			ca.addError(err)
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		names := unique(append(csr.DNSNames, csr.Subject.CommonName))
+		if err := ca.matchWhitelist(names); err != nil {
+			ca.addError(err)
+			http.Error(w, err.Error(), http.StatusUnauthorized)
+			return
+		}
+		if err := ca.authorized(names); err != nil {
+			ca.addError(err)
+			http.Error(w, err.Error(), http.StatusUnauthorized)
+			return
+		}
+		der, err := ca.leafCert(csr)
+		if err != nil {
+			err = fmt.Errorf("new-cert response: ca.leafCert: %v", err)
+			ca.addError(err)
+			http.Error(w, err.Error(), http.StatusBadRequest)
+		}
+		w.Header().Set("Link", fmt.Sprintf("<%s>; rel=up", ca.serverURL("/ca-cert")))
+		w.WriteHeader(http.StatusCreated)
+		w.Write(der)
+
+	// CA chain cert request.
+	case r.URL.Path == "/ca-cert":
+		w.Write(ca.rootCert)
+	}
+}
+
+func (ca *CAServer) addError(err error) {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	ca.errors = append(ca.errors, err)
+}
+
+func (ca *CAServer) serverURL(format string, arg ...interface{}) string {
+	return ca.server.URL + fmt.Sprintf(format, arg...)
+}
+
+func (ca *CAServer) matchWhitelist(dnsNames []string) error {
+	if len(ca.domainsWhitelist) == 0 {
+		return nil
+	}
+	var nomatch []string
+	for _, name := range dnsNames {
+		i := sort.SearchStrings(ca.domainsWhitelist, name)
+		if i == len(ca.domainsWhitelist) || ca.domainsWhitelist[i] != name {
+			nomatch = append(nomatch, name)
+		}
+	}
+	if len(nomatch) > 0 {
+		return fmt.Errorf("matchWhitelist: some domains don't match: %q", nomatch)
+	}
+	return nil
+}
+
+func (ca *CAServer) authorized(dnsNames []string) error {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	var noauthz []string
+	for _, name := range dnsNames {
+		authz, ok := ca.authorizations[name]
+		if !ok || authz.Status != "valid" {
+			noauthz = append(noauthz, name)
+		}
+	}
+	if len(noauthz) > 0 {
+		return fmt.Errorf("CAServer: no authz for %q", noauthz)
+	}
+	return nil
+}
+
+func (ca *CAServer) leafCert(csr *x509.CertificateRequest) (der []byte, err error) {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	ca.certCount++ // next leaf cert serial number
+	leaf := &x509.Certificate{
+		SerialNumber:          big.NewInt(int64(ca.certCount)),
+		Subject:               pkix.Name{Organization: []string{"Test Acme Co"}},
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().Add(90 * 24 * time.Hour),
+		KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+		DNSNames:              csr.DNSNames,
+		BasicConstraintsValid: true,
+	}
+	if len(csr.DNSNames) == 0 {
+		leaf.DNSNames = []string{csr.Subject.CommonName}
+	}
+	return x509.CreateCertificate(rand.Reader, leaf, ca.rootTemplate, csr.PublicKey, ca.rootKey)
+}
+
+func (ca *CAServer) addr(domain string) (string, error) {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	addr, ok := ca.domainAddr[domain]
+	if !ok {
+		return "", fmt.Errorf("CAServer: no addr resolution for %q", domain)
+	}
+	return addr, nil
+}
+
+func (ca *CAServer) verifyALPNChallenge(domain string) error {
+	const acmeALPNProto = "acme-tls/1"
+
+	addr, err := ca.addr(domain)
+	if err != nil {
+		return err
+	}
+	conn, err := tls.Dial("tcp", addr, &tls.Config{
+		ServerName:         domain,
+		InsecureSkipVerify: true,
+		NextProtos:         []string{acmeALPNProto},
+	})
+	if err != nil {
+		return err
+	}
+	if v := conn.ConnectionState().NegotiatedProtocol; v != acmeALPNProto {
+		return fmt.Errorf("CAServer: verifyALPNChallenge: negotiated proto is %q; want %q", v, acmeALPNProto)
+	}
+	if n := len(conn.ConnectionState().PeerCertificates); n != 1 {
+		return fmt.Errorf("len(PeerCertificates) = %d; want 1", n)
+	}
+	// TODO: verify conn.ConnectionState().PeerCertificates[0]
+	return nil
+}
+
+func decodePayload(v interface{}, r io.Reader) error {
+	var req struct{ Payload string }
+	if err := json.NewDecoder(r).Decode(&req); err != nil {
+		return err
+	}
+	payload, err := base64.RawURLEncoding.DecodeString(req.Payload)
+	if err != nil {
+		return err
+	}
+	return json.Unmarshal(payload, v)
+}
+
+func challengeToken(domain, challType string) string {
+	return fmt.Sprintf("token-%s-%s", domain, challType)
+}
+
+func unique(a []string) []string {
+	seen := make(map[string]bool)
+	var res []string
+	for _, s := range a {
+		if s != "" && !seen[s] {
+			seen[s] = true
+			res = append(res, s)
+		}
+	}
+	return res
+}

vendor/golang.org/x/crypto/acme/autocert/listener.go

@@ -0,0 +1,157 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package autocert
+
+import (
+	"crypto/tls"
+	"log"
+	"net"
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+)
+
+// NewListener returns a net.Listener that listens on the standard TLS
+// port (443) on all interfaces and returns *tls.Conn connections with
+// LetsEncrypt certificates for the provided domain or domains.
+//
+// It enables one-line HTTPS servers:
+//
+//     log.Fatal(http.Serve(autocert.NewListener("example.com"), handler))
+//
+// NewListener is a convenience function for a common configuration.
+// More complex or custom configurations can use the autocert.Manager
+// type instead.
+//
+// Use of this function implies acceptance of the LetsEncrypt Terms of
+// Service. If domains is not empty, the provided domains are passed
+// to HostWhitelist. If domains is empty, the listener will do
+// LetsEncrypt challenges for any requested domain, which is not
+// recommended.
+//
+// Certificates are cached in a "golang-autocert" directory under an
+// operating system-specific cache or temp directory. This may not
+// be suitable for servers spanning multiple machines.
+//
+// The returned listener uses a *tls.Config that enables HTTP/2, and
+// should only be used with servers that support HTTP/2.
+//
+// The returned Listener also enables TCP keep-alives on the accepted
+// connections. The returned *tls.Conn are returned before their TLS
+// handshake has completed.
+func NewListener(domains ...string) net.Listener {
+	m := &Manager{
+		Prompt: AcceptTOS,
+	}
+	if len(domains) > 0 {
+		m.HostPolicy = HostWhitelist(domains...)
+	}
+	dir := cacheDir()
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		log.Printf("warning: autocert.NewListener not using a cache: %v", err)
+	} else {
+		m.Cache = DirCache(dir)
+	}
+	return m.Listener()
+}
+
+// Listener listens on the standard TLS port (443) on all interfaces
+// and returns a net.Listener returning *tls.Conn connections.
+//
+// The returned listener uses a *tls.Config that enables HTTP/2, and
+// should only be used with servers that support HTTP/2.
+//
+// The returned Listener also enables TCP keep-alives on the accepted
+// connections. The returned *tls.Conn are returned before their TLS
+// handshake has completed.
+//
+// Unlike NewListener, it is the caller's responsibility to initialize
+// the Manager m's Prompt, Cache, HostPolicy, and other desired options.
+func (m *Manager) Listener() net.Listener {
+	ln := &listener{
+		m:    m,
+		conf: m.TLSConfig(),
+	}
+	ln.tcpListener, ln.tcpListenErr = net.Listen("tcp", ":443")
+	return ln
+}
+
+type listener struct {
+	m    *Manager
+	conf *tls.Config
+
+	tcpListener  net.Listener
+	tcpListenErr error
+}
+
+func (ln *listener) Accept() (net.Conn, error) {
+	if ln.tcpListenErr != nil {
+		return nil, ln.tcpListenErr
+	}
+	conn, err := ln.tcpListener.Accept()
+	if err != nil {
+		return nil, err
+	}
+	tcpConn := conn.(*net.TCPConn)
+
+	// Because Listener is a convenience function, help out with
+	// this too.  This is not possible for the caller to set once
+	// we return a *tcp.Conn wrapping an inaccessible net.Conn.
+	// If callers don't want this, they can do things the manual
+	// way and tweak as needed. But this is what net/http does
+	// itself, so copy that. If net/http changes, we can change
+	// here too.
+	tcpConn.SetKeepAlive(true)
+	tcpConn.SetKeepAlivePeriod(3 * time.Minute)
+
+	return tls.Server(tcpConn, ln.conf), nil
+}
+
+func (ln *listener) Addr() net.Addr {
+	if ln.tcpListener != nil {
+		return ln.tcpListener.Addr()
+	}
+	// net.Listen failed. Return something non-nil in case callers
+	// call Addr before Accept:
+	return &net.TCPAddr{IP: net.IP{0, 0, 0, 0}, Port: 443}
+}
+
+func (ln *listener) Close() error {
+	if ln.tcpListenErr != nil {
+		return ln.tcpListenErr
+	}
+	return ln.tcpListener.Close()
+}
+
+func homeDir() string {
+	if runtime.GOOS == "windows" {
+		return os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
+	}
+	if h := os.Getenv("HOME"); h != "" {
+		return h
+	}
+	return "/"
+}
+
+func cacheDir() string {
+	const base = "golang-autocert"
+	switch runtime.GOOS {
+	case "darwin":
+		return filepath.Join(homeDir(), "Library", "Caches", base)
+	case "windows":
+		for _, ev := range []string{"APPDATA", "CSIDL_APPDATA", "TEMP", "TMP"} {
+			if v := os.Getenv(ev); v != "" {
+				return filepath.Join(v, base)
+			}
+		}
+		// Worst case:
+		return filepath.Join(homeDir(), base)
+	}
+	if xdg := os.Getenv("XDG_CACHE_HOME"); xdg != "" {
+		return filepath.Join(xdg, base)
+	}
+	return filepath.Join(homeDir(), ".cache", base)
+}

vendor/golang.org/x/crypto/acme/autocert/renewal.go

@@ -0,0 +1,141 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package autocert
+
+import (
+	"context"
+	"crypto"
+	"sync"
+	"time"
+)
+
+// renewJitter is the maximum deviation from Manager.RenewBefore.
+const renewJitter = time.Hour
+
+// domainRenewal tracks the state used by the periodic timers
+// renewing a single domain's cert.
+type domainRenewal struct {
+	m   *Manager
+	ck  certKey
+	key crypto.Signer
+
+	timerMu sync.Mutex
+	timer   *time.Timer
+}
+
+// start starts a cert renewal timer at the time
+// defined by the certificate expiration time exp.
+//
+// If the timer is already started, calling start is a noop.
+func (dr *domainRenewal) start(exp time.Time) {
+	dr.timerMu.Lock()
+	defer dr.timerMu.Unlock()
+	if dr.timer != nil {
+		return
+	}
+	dr.timer = time.AfterFunc(dr.next(exp), dr.renew)
+}
+
+// stop stops the cert renewal timer.
+// If the timer is already stopped, calling stop is a noop.
+func (dr *domainRenewal) stop() {
+	dr.timerMu.Lock()
+	defer dr.timerMu.Unlock()
+	if dr.timer == nil {
+		return
+	}
+	dr.timer.Stop()
+	dr.timer = nil
+}
+
+// renew is called periodically by a timer.
+// The first renew call is kicked off by dr.start.
+func (dr *domainRenewal) renew() {
+	dr.timerMu.Lock()
+	defer dr.timerMu.Unlock()
+	if dr.timer == nil {
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
+	defer cancel()
+	// TODO: rotate dr.key at some point?
+	next, err := dr.do(ctx)
+	if err != nil {
+		next = renewJitter / 2
+		next += time.Duration(pseudoRand.int63n(int64(next)))
+	}
+	dr.timer = time.AfterFunc(next, dr.renew)
+	testDidRenewLoop(next, err)
+}
+
+// updateState locks and replaces the relevant Manager.state item with the given
+// state. It additionally updates dr.key with the given state's key.
+func (dr *domainRenewal) updateState(state *certState) {
+	dr.m.stateMu.Lock()
+	defer dr.m.stateMu.Unlock()
+	dr.key = state.key
+	dr.m.state[dr.ck] = state
+}
+
+// do is similar to Manager.createCert but it doesn't lock a Manager.state item.
+// Instead, it requests a new certificate independently and, upon success,
+// replaces dr.m.state item with a new one and updates cache for the given domain.
+//
+// It may lock and update the Manager.state if the expiration date of the currently
+// cached cert is far enough in the future.
+//
+// The returned value is a time interval after which the renewal should occur again.
+func (dr *domainRenewal) do(ctx context.Context) (time.Duration, error) {
+	// a race is likely unavoidable in a distributed environment
+	// but we try nonetheless
+	if tlscert, err := dr.m.cacheGet(ctx, dr.ck); err == nil {
+		next := dr.next(tlscert.Leaf.NotAfter)
+		if next > dr.m.renewBefore()+renewJitter {
+			signer, ok := tlscert.PrivateKey.(crypto.Signer)
+			if ok {
+				state := &certState{
+					key:  signer,
+					cert: tlscert.Certificate,
+					leaf: tlscert.Leaf,
+				}
+				dr.updateState(state)
+				return next, nil
+			}
+		}
+	}
+
+	der, leaf, err := dr.m.authorizedCert(ctx, dr.key, dr.ck)
+	if err != nil {
+		return 0, err
+	}
+	state := &certState{
+		key:  dr.key,
+		cert: der,
+		leaf: leaf,
+	}
+	tlscert, err := state.tlscert()
+	if err != nil {
+		return 0, err
+	}
+	if err := dr.m.cachePut(ctx, dr.ck, tlscert); err != nil {
+		return 0, err
+	}
+	dr.updateState(state)
+	return dr.next(leaf.NotAfter), nil
+}
+
+func (dr *domainRenewal) next(expiry time.Time) time.Duration {
+	d := expiry.Sub(dr.m.now()) - dr.m.renewBefore()
+	// add a bit of randomness to renew deadline
+	n := pseudoRand.int63n(int64(renewJitter))
+	d -= time.Duration(n)
+	if d < 0 {
+		return 0
+	}
+	return d
+}
+
+var testDidRenewLoop = func(next time.Duration, err error) {}

vendor/golang.org/x/crypto/acme/autocert/renewal_test.go

@@ -0,0 +1,329 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package autocert
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"golang.org/x/crypto/acme"
+)
+
+func TestRenewalNext(t *testing.T) {
+	now := time.Now()
+	man := &Manager{
+		RenewBefore: 7 * 24 * time.Hour,
+		nowFunc:     func() time.Time { return now },
+	}
+	defer man.stopRenew()
+	tt := []struct {
+		expiry   time.Time
+		min, max time.Duration
+	}{
+		{now.Add(90 * 24 * time.Hour), 83*24*time.Hour - renewJitter, 83 * 24 * time.Hour},
+		{now.Add(time.Hour), 0, 1},
+		{now, 0, 1},
+		{now.Add(-time.Hour), 0, 1},
+	}
+
+	dr := &domainRenewal{m: man}
+	for i, test := range tt {
+		next := dr.next(test.expiry)
+		if next < test.min || test.max < next {
+			t.Errorf("%d: next = %v; want between %v and %v", i, next, test.min, test.max)
+		}
+	}
+}
+
+func TestRenewFromCache(t *testing.T) {
+	// ACME CA server stub
+	var ca *httptest.Server
+	ca = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Replay-Nonce", "nonce")
+		if r.Method == "HEAD" {
+			// a nonce request
+			return
+		}
+
+		switch r.URL.Path {
+		// discovery
+		case "/":
+			if err := discoTmpl.Execute(w, ca.URL); err != nil {
+				t.Fatalf("discoTmpl: %v", err)
+			}
+		// client key registration
+		case "/new-reg":
+			w.Write([]byte("{}"))
+		// domain authorization
+		case "/new-authz":
+			w.Header().Set("Location", ca.URL+"/authz/1")
+			w.WriteHeader(http.StatusCreated)
+			w.Write([]byte(`{"status": "valid"}`))
+		// cert request
+		case "/new-cert":
+			var req struct {
+				CSR string `json:"csr"`
+			}
+			decodePayload(&req, r.Body)
+			b, _ := base64.RawURLEncoding.DecodeString(req.CSR)
+			csr, err := x509.ParseCertificateRequest(b)
+			if err != nil {
+				t.Fatalf("new-cert: CSR: %v", err)
+			}
+			der, err := dummyCert(csr.PublicKey, exampleDomain)
+			if err != nil {
+				t.Fatalf("new-cert: dummyCert: %v", err)
+			}
+			chainUp := fmt.Sprintf("<%s/ca-cert>; rel=up", ca.URL)
+			w.Header().Set("Link", chainUp)
+			w.WriteHeader(http.StatusCreated)
+			w.Write(der)
+		// CA chain cert
+		case "/ca-cert":
+			der, err := dummyCert(nil, "ca")
+			if err != nil {
+				t.Fatalf("ca-cert: dummyCert: %v", err)
+			}
+			w.Write(der)
+		default:
+			t.Errorf("unrecognized r.URL.Path: %s", r.URL.Path)
+		}
+	}))
+	defer ca.Close()
+
+	man := &Manager{
+		Prompt:      AcceptTOS,
+		Cache:       newMemCache(t),
+		RenewBefore: 24 * time.Hour,
+		Client: &acme.Client{
+			DirectoryURL: ca.URL,
+		},
+	}
+	defer man.stopRenew()
+
+	// cache an almost expired cert
+	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	now := time.Now()
+	cert, err := dateDummyCert(key.Public(), now.Add(-2*time.Hour), now.Add(time.Minute), exampleDomain)
+	if err != nil {
+		t.Fatal(err)
+	}
+	tlscert := &tls.Certificate{PrivateKey: key, Certificate: [][]byte{cert}}
+	if err := man.cachePut(context.Background(), exampleCertKey, tlscert); err != nil {
+		t.Fatal(err)
+	}
+
+	// veriy the renewal happened
+	defer func() {
+		testDidRenewLoop = func(next time.Duration, err error) {}
+	}()
+	done := make(chan struct{})
+	testDidRenewLoop = func(next time.Duration, err error) {
+		defer close(done)
+		if err != nil {
+			t.Errorf("testDidRenewLoop: %v", err)
+		}
+		// Next should be about 90 days:
+		// dummyCert creates 90days expiry + account for man.RenewBefore.
+		// Previous expiration was within 1 min.
+		future := 88 * 24 * time.Hour
+		if next < future {
+			t.Errorf("testDidRenewLoop: next = %v; want >= %v", next, future)
+		}
+
+		// ensure the new cert is cached
+		after := time.Now().Add(future)
+		tlscert, err := man.cacheGet(context.Background(), exampleCertKey)
+		if err != nil {
+			t.Fatalf("man.cacheGet: %v", err)
+		}
+		if !tlscert.Leaf.NotAfter.After(after) {
+			t.Errorf("cache leaf.NotAfter = %v; want > %v", tlscert.Leaf.NotAfter, after)
+		}
+
+		// verify the old cert is also replaced in memory
+		man.stateMu.Lock()
+		defer man.stateMu.Unlock()
+		s := man.state[exampleCertKey]
+		if s == nil {
+			t.Fatalf("m.state[%q] is nil", exampleCertKey)
+		}
+		tlscert, err = s.tlscert()
+		if err != nil {
+			t.Fatalf("s.tlscert: %v", err)
+		}
+		if !tlscert.Leaf.NotAfter.After(after) {
+			t.Errorf("state leaf.NotAfter = %v; want > %v", tlscert.Leaf.NotAfter, after)
+		}
+	}
+
+	// trigger renew
+	hello := clientHelloInfo(exampleDomain, true)
+	if _, err := man.GetCertificate(hello); err != nil {
+		t.Fatal(err)
+	}
+
+	// wait for renew loop
+	select {
+	case <-time.After(10 * time.Second):
+		t.Fatal("renew took too long to occur")
+	case <-done:
+	}
+}
+
+func TestRenewFromCacheAlreadyRenewed(t *testing.T) {
+	man := &Manager{
+		Prompt:      AcceptTOS,
+		Cache:       newMemCache(t),
+		RenewBefore: 24 * time.Hour,
+		Client: &acme.Client{
+			DirectoryURL: "invalid",
+		},
+	}
+	defer man.stopRenew()
+
+	// cache a recently renewed cert with a different private key
+	newKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	now := time.Now()
+	newCert, err := dateDummyCert(newKey.Public(), now.Add(-2*time.Hour), now.Add(time.Hour*24*90), exampleDomain)
+	if err != nil {
+		t.Fatal(err)
+	}
+	newLeaf, err := validCert(exampleCertKey, [][]byte{newCert}, newKey, now)
+	if err != nil {
+		t.Fatal(err)
+	}
+	newTLSCert := &tls.Certificate{PrivateKey: newKey, Certificate: [][]byte{newCert}, Leaf: newLeaf}
+	if err := man.cachePut(context.Background(), exampleCertKey, newTLSCert); err != nil {
+		t.Fatal(err)
+	}
+
+	// set internal state to an almost expired cert
+	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	oldCert, err := dateDummyCert(key.Public(), now.Add(-2*time.Hour), now.Add(time.Minute), exampleDomain)
+	if err != nil {
+		t.Fatal(err)
+	}
+	oldLeaf, err := validCert(exampleCertKey, [][]byte{oldCert}, key, now)
+	if err != nil {
+		t.Fatal(err)
+	}
+	man.stateMu.Lock()
+	if man.state == nil {
+		man.state = make(map[certKey]*certState)
+	}
+	s := &certState{
+		key:  key,
+		cert: [][]byte{oldCert},
+		leaf: oldLeaf,
+	}
+	man.state[exampleCertKey] = s
+	man.stateMu.Unlock()
+
+	// veriy the renewal accepted the newer cached cert
+	defer func() {
+		testDidRenewLoop = func(next time.Duration, err error) {}
+	}()
+	done := make(chan struct{})
+	testDidRenewLoop = func(next time.Duration, err error) {
+		defer close(done)
+		if err != nil {
+			t.Errorf("testDidRenewLoop: %v", err)
+		}
+		// Next should be about 90 days
+		// Previous expiration was within 1 min.
+		future := 88 * 24 * time.Hour
+		if next < future {
+			t.Errorf("testDidRenewLoop: next = %v; want >= %v", next, future)
+		}
+
+		// ensure the cached cert was not modified
+		tlscert, err := man.cacheGet(context.Background(), exampleCertKey)
+		if err != nil {
+			t.Fatalf("man.cacheGet: %v", err)
+		}
+		if !tlscert.Leaf.NotAfter.Equal(newLeaf.NotAfter) {
+			t.Errorf("cache leaf.NotAfter = %v; want == %v", tlscert.Leaf.NotAfter, newLeaf.NotAfter)
+		}
+
+		// verify the old cert is also replaced in memory
+		man.stateMu.Lock()
+		defer man.stateMu.Unlock()
+		s := man.state[exampleCertKey]
+		if s == nil {
+			t.Fatalf("m.state[%q] is nil", exampleCertKey)
+		}
+		stateKey := s.key.Public().(*ecdsa.PublicKey)
+		if stateKey.X.Cmp(newKey.X) != 0 || stateKey.Y.Cmp(newKey.Y) != 0 {
+			t.Fatalf("state key was not updated from cache x: %v y: %v; want x: %v y: %v", stateKey.X, stateKey.Y, newKey.X, newKey.Y)
+		}
+		tlscert, err = s.tlscert()
+		if err != nil {
+			t.Fatalf("s.tlscert: %v", err)
+		}
+		if !tlscert.Leaf.NotAfter.Equal(newLeaf.NotAfter) {
+			t.Errorf("state leaf.NotAfter = %v; want == %v", tlscert.Leaf.NotAfter, newLeaf.NotAfter)
+		}
+
+		// verify the private key is replaced in the renewal state
+		r := man.renewal[exampleCertKey]
+		if r == nil {
+			t.Fatalf("m.renewal[%q] is nil", exampleCertKey)
+		}
+		renewalKey := r.key.Public().(*ecdsa.PublicKey)
+		if renewalKey.X.Cmp(newKey.X) != 0 || renewalKey.Y.Cmp(newKey.Y) != 0 {
+			t.Fatalf("renewal private key was not updated from cache x: %v y: %v; want x: %v y: %v", renewalKey.X, renewalKey.Y, newKey.X, newKey.Y)
+		}
+
+	}
+
+	// assert the expiring cert is returned from state
+	hello := clientHelloInfo(exampleDomain, true)
+	tlscert, err := man.GetCertificate(hello)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !oldLeaf.NotAfter.Equal(tlscert.Leaf.NotAfter) {
+		t.Errorf("state leaf.NotAfter = %v; want == %v", tlscert.Leaf.NotAfter, oldLeaf.NotAfter)
+	}
+
+	// trigger renew
+	go man.renew(exampleCertKey, s.key, s.leaf.NotAfter)
+
+	// wait for renew loop
+	select {
+	case <-time.After(10 * time.Second):
+		t.Fatal("renew took too long to occur")
+	case <-done:
+		// assert the new cert is returned from state after renew
+		hello := clientHelloInfo(exampleDomain, true)
+		tlscert, err := man.GetCertificate(hello)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !newTLSCert.Leaf.NotAfter.Equal(tlscert.Leaf.NotAfter) {
+			t.Errorf("state leaf.NotAfter = %v; want == %v", tlscert.Leaf.NotAfter, newTLSCert.Leaf.NotAfter)
+		}
+	}
+}

vendor/golang.org/x/crypto/acme/http.go

@@ -0,0 +1,281 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+	"bytes"
+	"context"
+	"crypto"
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"math/big"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// retryTimer encapsulates common logic for retrying unsuccessful requests.
+// It is not safe for concurrent use.
+type retryTimer struct {
+	// backoffFn provides backoff delay sequence for retries.
+	// See Client.RetryBackoff doc comment.
+	backoffFn func(n int, r *http.Request, res *http.Response) time.Duration
+	// n is the current retry attempt.
+	n int
+}
+
+func (t *retryTimer) inc() {
+	t.n++
+}
+
+// backoff pauses the current goroutine as described in Client.RetryBackoff.
+func (t *retryTimer) backoff(ctx context.Context, r *http.Request, res *http.Response) error {
+	d := t.backoffFn(t.n, r, res)
+	if d <= 0 {
+		return fmt.Errorf("acme: no more retries for %s; tried %d time(s)", r.URL, t.n)
+	}
+	wakeup := time.NewTimer(d)
+	defer wakeup.Stop()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-wakeup.C:
+		return nil
+	}
+}
+
+func (c *Client) retryTimer() *retryTimer {
+	f := c.RetryBackoff
+	if f == nil {
+		f = defaultBackoff
+	}
+	return &retryTimer{backoffFn: f}
+}
+
+// defaultBackoff provides default Client.RetryBackoff implementation
+// using a truncated exponential backoff algorithm,
+// as described in Client.RetryBackoff.
+//
+// The n argument is always bounded between 1 and 30.
+// The returned value is always greater than 0.
+func defaultBackoff(n int, r *http.Request, res *http.Response) time.Duration {
+	const max = 10 * time.Second
+	var jitter time.Duration
+	if x, err := rand.Int(rand.Reader, big.NewInt(1000)); err == nil {
+		// Set the minimum to 1ms to avoid a case where
+		// an invalid Retry-After value is parsed into 0 below,
+		// resulting in the 0 returned value which would unintentionally
+		// stop the retries.
+		jitter = (1 + time.Duration(x.Int64())) * time.Millisecond
+	}
+	if v, ok := res.Header["Retry-After"]; ok {
+		return retryAfter(v[0]) + jitter
+	}
+
+	if n < 1 {
+		n = 1
+	}
+	if n > 30 {
+		n = 30
+	}
+	d := time.Duration(1<<uint(n-1))*time.Second + jitter
+	if d > max {
+		return max
+	}
+	return d
+}
+
+// retryAfter parses a Retry-After HTTP header value,
+// trying to convert v into an int (seconds) or use http.ParseTime otherwise.
+// It returns zero value if v cannot be parsed.
+func retryAfter(v string) time.Duration {
+	if i, err := strconv.Atoi(v); err == nil {
+		return time.Duration(i) * time.Second
+	}
+	t, err := http.ParseTime(v)
+	if err != nil {
+		return 0
+	}
+	return t.Sub(timeNow())
+}
+
+// resOkay is a function that reports whether the provided response is okay.
+// It is expected to keep the response body unread.
+type resOkay func(*http.Response) bool
+
+// wantStatus returns a function which reports whether the code
+// matches the status code of a response.
+func wantStatus(codes ...int) resOkay {
+	return func(res *http.Response) bool {
+		for _, code := range codes {
+			if code == res.StatusCode {
+				return true
+			}
+		}
+		return false
+	}
+}
+
+// get issues an unsigned GET request to the specified URL.
+// It returns a non-error value only when ok reports true.
+//
+// get retries unsuccessful attempts according to c.RetryBackoff
+// until the context is done or a non-retriable error is received.
+func (c *Client) get(ctx context.Context, url string, ok resOkay) (*http.Response, error) {
+	retry := c.retryTimer()
+	for {
+		req, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			return nil, err
+		}
+		res, err := c.doNoRetry(ctx, req)
+		switch {
+		case err != nil:
+			return nil, err
+		case ok(res):
+			return res, nil
+		case isRetriable(res.StatusCode):
+			retry.inc()
+			resErr := responseError(res)
+			res.Body.Close()
+			// Ignore the error value from retry.backoff
+			// and return the one from last retry, as received from the CA.
+			if retry.backoff(ctx, req, res) != nil {
+				return nil, resErr
+			}
+		default:
+			defer res.Body.Close()
+			return nil, responseError(res)
+		}
+	}
+}
+
+// post issues a signed POST request in JWS format using the provided key
+// to the specified URL.
+// It returns a non-error value only when ok reports true.
+//
+// post retries unsuccessful attempts according to c.RetryBackoff
+// until the context is done or a non-retriable error is received.
+// It uses postNoRetry to make individual requests.
+func (c *Client) post(ctx context.Context, key crypto.Signer, url string, body interface{}, ok resOkay) (*http.Response, error) {
+	retry := c.retryTimer()
+	for {
+		res, req, err := c.postNoRetry(ctx, key, url, body)
+		if err != nil {
+			return nil, err
+		}
+		if ok(res) {
+			return res, nil
+		}
+		resErr := responseError(res)
+		res.Body.Close()
+		switch {
+		// Check for bad nonce before isRetriable because it may have been returned
+		// with an unretriable response code such as 400 Bad Request.
+		case isBadNonce(resErr):
+			// Consider any previously stored nonce values to be invalid.
+			c.clearNonces()
+		case !isRetriable(res.StatusCode):
+			return nil, resErr
+		}
+		retry.inc()
+		// Ignore the error value from retry.backoff
+		// and return the one from last retry, as received from the CA.
+		if err := retry.backoff(ctx, req, res); err != nil {
+			return nil, resErr
+		}
+	}
+}
+
+// postNoRetry signs the body with the given key and POSTs it to the provided url.
+// The body argument must be JSON-serializable.
+// It is used by c.post to retry unsuccessful attempts.
+func (c *Client) postNoRetry(ctx context.Context, key crypto.Signer, url string, body interface{}) (*http.Response, *http.Request, error) {
+	nonce, err := c.popNonce(ctx, url)
+	if err != nil {
+		return nil, nil, err
+	}
+	b, err := jwsEncodeJSON(body, key, nonce)
+	if err != nil {
+		return nil, nil, err
+	}
+	req, err := http.NewRequest("POST", url, bytes.NewReader(b))
+	if err != nil {
+		return nil, nil, err
+	}
+	req.Header.Set("Content-Type", "application/jose+json")
+	res, err := c.doNoRetry(ctx, req)
+	if err != nil {
+		return nil, nil, err
+	}
+	c.addNonce(res.Header)
+	return res, req, nil
+}
+
+// doNoRetry issues a request req, replacing its context (if any) with ctx.
+func (c *Client) doNoRetry(ctx context.Context, req *http.Request) (*http.Response, error) {
+	res, err := c.httpClient().Do(req.WithContext(ctx))
+	if err != nil {
+		select {
+		case <-ctx.Done():
+			// Prefer the unadorned context error.
+			// (The acme package had tests assuming this, previously from ctxhttp's
+			// behavior, predating net/http supporting contexts natively)
+			// TODO(bradfitz): reconsider this in the future. But for now this
+			// requires no test updates.
+			return nil, ctx.Err()
+		default:
+			return nil, err
+		}
+	}
+	return res, nil
+}
+
+func (c *Client) httpClient() *http.Client {
+	if c.HTTPClient != nil {
+		return c.HTTPClient
+	}
+	return http.DefaultClient
+}
+
+// isBadNonce reports whether err is an ACME "badnonce" error.
+func isBadNonce(err error) bool {
+	// According to the spec badNonce is urn:ietf:params:acme:error:badNonce.
+	// However, ACME servers in the wild return their versions of the error.
+	// See https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-5.4
+	// and https://github.com/letsencrypt/boulder/blob/0e07eacb/docs/acme-divergences.md#section-66.
+	ae, ok := err.(*Error)
+	return ok && strings.HasSuffix(strings.ToLower(ae.ProblemType), ":badnonce")
+}
+
+// isRetriable reports whether a request can be retried
+// based on the response status code.
+//
+// Note that a "bad nonce" error is returned with a non-retriable 400 Bad Request code.
+// Callers should parse the response and check with isBadNonce.
+func isRetriable(code int) bool {
+	return code <= 399 || code >= 500 || code == http.StatusTooManyRequests
+}
+
+// responseError creates an error of Error type from resp.
+func responseError(resp *http.Response) error {
+	// don't care if ReadAll returns an error:
+	// json.Unmarshal will fail in that case anyway
+	b, _ := ioutil.ReadAll(resp.Body)
+	e := &wireError{Status: resp.StatusCode}
+	if err := json.Unmarshal(b, e); err != nil {
+		// this is not a regular error response:
+		// populate detail with anything we received,
+		// e.Status will already contain HTTP response code value
+		e.Detail = string(b)
+		if e.Detail == "" {
+			e.Detail = resp.Status
+		}
+	}
+	return e.error(resp.Header)
+}

vendor/golang.org/x/crypto/acme/http_test.go

@@ -0,0 +1,209 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestDefaultBackoff(t *testing.T) {
+	tt := []struct {
+		nretry     int
+		retryAfter string        // Retry-After header
+		out        time.Duration // expected min; max = min + jitter
+	}{
+		{-1, "", time.Second},       // verify the lower bound is 1
+		{0, "", time.Second},        // verify the lower bound is 1
+		{100, "", 10 * time.Second}, // verify the ceiling
+		{1, "3600", time.Hour},      // verify the header value is used
+		{1, "", 1 * time.Second},
+		{2, "", 2 * time.Second},
+		{3, "", 4 * time.Second},
+		{4, "", 8 * time.Second},
+	}
+	for i, test := range tt {
+		r := httptest.NewRequest("GET", "/", nil)
+		resp := &http.Response{Header: http.Header{}}
+		if test.retryAfter != "" {
+			resp.Header.Set("Retry-After", test.retryAfter)
+		}
+		d := defaultBackoff(test.nretry, r, resp)
+		max := test.out + time.Second // + max jitter
+		if d < test.out || max < d {
+			t.Errorf("%d: defaultBackoff(%v) = %v; want between %v and %v", i, test.nretry, d, test.out, max)
+		}
+	}
+}
+
+func TestErrorResponse(t *testing.T) {
+	s := `{
+		"status": 400,
+		"type": "urn:acme:error:xxx",
+		"detail": "text"
+	}`
+	res := &http.Response{
+		StatusCode: 400,
+		Status:     "400 Bad Request",
+		Body:       ioutil.NopCloser(strings.NewReader(s)),
+		Header:     http.Header{"X-Foo": {"bar"}},
+	}
+	err := responseError(res)
+	v, ok := err.(*Error)
+	if !ok {
+		t.Fatalf("err = %+v (%T); want *Error type", err, err)
+	}
+	if v.StatusCode != 400 {
+		t.Errorf("v.StatusCode = %v; want 400", v.StatusCode)
+	}
+	if v.ProblemType != "urn:acme:error:xxx" {
+		t.Errorf("v.ProblemType = %q; want urn:acme:error:xxx", v.ProblemType)
+	}
+	if v.Detail != "text" {
+		t.Errorf("v.Detail = %q; want text", v.Detail)
+	}
+	if !reflect.DeepEqual(v.Header, res.Header) {
+		t.Errorf("v.Header = %+v; want %+v", v.Header, res.Header)
+	}
+}
+
+func TestPostWithRetries(t *testing.T) {
+	var count int
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		count++
+		w.Header().Set("Replay-Nonce", fmt.Sprintf("nonce%d", count))
+		if r.Method == "HEAD" {
+			// We expect the client to do 2 head requests to fetch
+			// nonces, one to start and another after getting badNonce
+			return
+		}
+
+		head, err := decodeJWSHead(r)
+		switch {
+		case err != nil:
+			t.Errorf("decodeJWSHead: %v", err)
+		case head.Nonce == "":
+			t.Error("head.Nonce is empty")
+		case head.Nonce == "nonce1":
+			// Return a badNonce error to force the call to retry.
+			w.Header().Set("Retry-After", "0")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(`{"type":"urn:ietf:params:acme:error:badNonce"}`))
+			return
+		}
+		// Make client.Authorize happy; we're not testing its result.
+		w.WriteHeader(http.StatusCreated)
+		w.Write([]byte(`{"status":"valid"}`))
+	}))
+	defer ts.Close()
+
+	client := &Client{Key: testKey, dir: &Directory{AuthzURL: ts.URL}}
+	// This call will fail with badNonce, causing a retry
+	if _, err := client.Authorize(context.Background(), "example.com"); err != nil {
+		t.Errorf("client.Authorize 1: %v", err)
+	}
+	if count != 4 {
+		t.Errorf("total requests count: %d; want 4", count)
+	}
+}
+
+func TestRetryErrorType(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Replay-Nonce", "nonce")
+		w.WriteHeader(http.StatusTooManyRequests)
+		w.Write([]byte(`{"type":"rateLimited"}`))
+	}))
+	defer ts.Close()
+
+	client := &Client{
+		Key: testKey,
+		RetryBackoff: func(n int, r *http.Request, res *http.Response) time.Duration {
+			// Do no retries.
+			return 0
+		},
+		dir: &Directory{AuthzURL: ts.URL},
+	}
+
+	t.Run("post", func(t *testing.T) {
+		testRetryErrorType(t, func() error {
+			_, err := client.Authorize(context.Background(), "example.com")
+			return err
+		})
+	})
+	t.Run("get", func(t *testing.T) {
+		testRetryErrorType(t, func() error {
+			_, err := client.GetAuthorization(context.Background(), ts.URL)
+			return err
+		})
+	})
+}
+
+func testRetryErrorType(t *testing.T, callClient func() error) {
+	t.Helper()
+	err := callClient()
+	if err == nil {
+		t.Fatal("client.Authorize returned nil error")
+	}
+	acmeErr, ok := err.(*Error)
+	if !ok {
+		t.Fatalf("err is %v (%T); want *Error", err, err)
+	}
+	if acmeErr.StatusCode != http.StatusTooManyRequests {
+		t.Errorf("acmeErr.StatusCode = %d; want %d", acmeErr.StatusCode, http.StatusTooManyRequests)
+	}
+	if acmeErr.ProblemType != "rateLimited" {
+		t.Errorf("acmeErr.ProblemType = %q; want 'rateLimited'", acmeErr.ProblemType)
+	}
+}
+
+func TestRetryBackoffArgs(t *testing.T) {
+	const resCode = http.StatusInternalServerError
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Replay-Nonce", "test-nonce")
+		w.WriteHeader(resCode)
+	}))
+	defer ts.Close()
+
+	// Canceled in backoff.
+	ctx, cancel := context.WithCancel(context.Background())
+
+	var nretry int
+	backoff := func(n int, r *http.Request, res *http.Response) time.Duration {
+		nretry++
+		if n != nretry {
+			t.Errorf("n = %d; want %d", n, nretry)
+		}
+		if nretry == 3 {
+			cancel()
+		}
+
+		if r == nil {
+			t.Error("r is nil")
+		}
+		if res.StatusCode != resCode {
+			t.Errorf("res.StatusCode = %d; want %d", res.StatusCode, resCode)
+		}
+		return time.Millisecond
+	}
+
+	client := &Client{
+		Key:          testKey,
+		RetryBackoff: backoff,
+		dir:          &Directory{AuthzURL: ts.URL},
+	}
+	if _, err := client.Authorize(ctx, "example.com"); err == nil {
+		t.Error("err is nil")
+	}
+	if nretry != 3 {
+		t.Errorf("nretry = %d; want 3", nretry)
+	}
+}

vendor/golang.org/x/crypto/acme/jws.go

@@ -0,0 +1,153 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	_ "crypto/sha512" // need for EC keys
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"math/big"
+)
+
+// jwsEncodeJSON signs claimset using provided key and a nonce.
+// The result is serialized in JSON format.
+// See https://tools.ietf.org/html/rfc7515#section-7.
+func jwsEncodeJSON(claimset interface{}, key crypto.Signer, nonce string) ([]byte, error) {
+	jwk, err := jwkEncode(key.Public())
+	if err != nil {
+		return nil, err
+	}
+	alg, sha := jwsHasher(key)
+	if alg == "" || !sha.Available() {
+		return nil, ErrUnsupportedKey
+	}
+	phead := fmt.Sprintf(`{"alg":%q,"jwk":%s,"nonce":%q}`, alg, jwk, nonce)
+	phead = base64.RawURLEncoding.EncodeToString([]byte(phead))
+	cs, err := json.Marshal(claimset)
+	if err != nil {
+		return nil, err
+	}
+	payload := base64.RawURLEncoding.EncodeToString(cs)
+	hash := sha.New()
+	hash.Write([]byte(phead + "." + payload))
+	sig, err := jwsSign(key, sha, hash.Sum(nil))
+	if err != nil {
+		return nil, err
+	}
+
+	enc := struct {
+		Protected string `json:"protected"`
+		Payload   string `json:"payload"`
+		Sig       string `json:"signature"`
+	}{
+		Protected: phead,
+		Payload:   payload,
+		Sig:       base64.RawURLEncoding.EncodeToString(sig),
+	}
+	return json.Marshal(&enc)
+}
+
+// jwkEncode encodes public part of an RSA or ECDSA key into a JWK.
+// The result is also suitable for creating a JWK thumbprint.
+// https://tools.ietf.org/html/rfc7517
+func jwkEncode(pub crypto.PublicKey) (string, error) {
+	switch pub := pub.(type) {
+	case *rsa.PublicKey:
+		// https://tools.ietf.org/html/rfc7518#section-6.3.1
+		n := pub.N
+		e := big.NewInt(int64(pub.E))
+		// Field order is important.
+		// See https://tools.ietf.org/html/rfc7638#section-3.3 for details.
+		return fmt.Sprintf(`{"e":"%s","kty":"RSA","n":"%s"}`,
+			base64.RawURLEncoding.EncodeToString(e.Bytes()),
+			base64.RawURLEncoding.EncodeToString(n.Bytes()),
+		), nil
+	case *ecdsa.PublicKey:
+		// https://tools.ietf.org/html/rfc7518#section-6.2.1
+		p := pub.Curve.Params()
+		n := p.BitSize / 8
+		if p.BitSize%8 != 0 {
+			n++
+		}
+		x := pub.X.Bytes()
+		if n > len(x) {
+			x = append(make([]byte, n-len(x)), x...)
+		}
+		y := pub.Y.Bytes()
+		if n > len(y) {
+			y = append(make([]byte, n-len(y)), y...)
+		}
+		// Field order is important.
+		// See https://tools.ietf.org/html/rfc7638#section-3.3 for details.
+		return fmt.Sprintf(`{"crv":"%s","kty":"EC","x":"%s","y":"%s"}`,
+			p.Name,
+			base64.RawURLEncoding.EncodeToString(x),
+			base64.RawURLEncoding.EncodeToString(y),
+		), nil
+	}
+	return "", ErrUnsupportedKey
+}
+
+// jwsSign signs the digest using the given key.
+// It returns ErrUnsupportedKey if the key type is unknown.
+// The hash is used only for RSA keys.
+func jwsSign(key crypto.Signer, hash crypto.Hash, digest []byte) ([]byte, error) {
+	switch key := key.(type) {
+	case *rsa.PrivateKey:
+		return key.Sign(rand.Reader, digest, hash)
+	case *ecdsa.PrivateKey:
+		r, s, err := ecdsa.Sign(rand.Reader, key, digest)
+		if err != nil {
+			return nil, err
+		}
+		rb, sb := r.Bytes(), s.Bytes()
+		size := key.Params().BitSize / 8
+		if size%8 > 0 {
+			size++
+		}
+		sig := make([]byte, size*2)
+		copy(sig[size-len(rb):], rb)
+		copy(sig[size*2-len(sb):], sb)
+		return sig, nil
+	}
+	return nil, ErrUnsupportedKey
+}
+
+// jwsHasher indicates suitable JWS algorithm name and a hash function
+// to use for signing a digest with the provided key.
+// It returns ("", 0) if the key is not supported.
+func jwsHasher(key crypto.Signer) (string, crypto.Hash) {
+	switch key := key.(type) {
+	case *rsa.PrivateKey:
+		return "RS256", crypto.SHA256
+	case *ecdsa.PrivateKey:
+		switch key.Params().Name {
+		case "P-256":
+			return "ES256", crypto.SHA256
+		case "P-384":
+			return "ES384", crypto.SHA384
+		case "P-521":
+			return "ES512", crypto.SHA512
+		}
+	}
+	return "", 0
+}
+
+// JWKThumbprint creates a JWK thumbprint out of pub
+// as specified in https://tools.ietf.org/html/rfc7638.
+func JWKThumbprint(pub crypto.PublicKey) (string, error) {
+	jwk, err := jwkEncode(pub)
+	if err != nil {
+		return "", err
+	}
+	b := sha256.Sum256([]byte(jwk))
+	return base64.RawURLEncoding.EncodeToString(b[:]), nil
+}

vendor/golang.org/x/crypto/acme/jws_test.go

@@ -0,0 +1,319 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"encoding/pem"
+	"fmt"
+	"math/big"
+	"testing"
+)
+
+const (
+	testKeyPEM = `
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+`
+
+	// This thumbprint is for the testKey defined above.
+	testKeyThumbprint = "6nicxzh6WETQlrvdchkz-U3e3DOQZ4heJKU63rfqMqQ"
+
+	// openssl ecparam -name secp256k1 -genkey -noout
+	testKeyECPEM = `
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIK07hGLr0RwyUdYJ8wbIiBS55CjnkMD23DWr+ccnypWLoAoGCCqGSM49
+AwEHoUQDQgAE5lhEug5xK4xBDZ2nAbaxLtaLiv85bxJ7ePd1dkO23HThqIrvawF5
+QAaS/RNouybCiRhRjI3EaxLkQwgrCw0gqQ==
+-----END EC PRIVATE KEY-----
+`
+	// openssl ecparam -name secp384r1 -genkey -noout
+	testKeyEC384PEM = `
+-----BEGIN EC PRIVATE KEY-----
+MIGkAgEBBDAQ4lNtXRORWr1bgKR1CGysr9AJ9SyEk4jiVnlUWWUChmSNL+i9SLSD
+Oe/naPqXJ6CgBwYFK4EEACKhZANiAAQzKtj+Ms0vHoTX5dzv3/L5YMXOWuI5UKRj
+JigpahYCqXD2BA1j0E/2xt5vlPf+gm0PL+UHSQsCokGnIGuaHCsJAp3ry0gHQEke
+WYXapUUFdvaK1R2/2hn5O+eiQM8YzCg=
+-----END EC PRIVATE KEY-----
+`
+	// openssl ecparam -name secp521r1 -genkey -noout
+	testKeyEC512PEM = `
+-----BEGIN EC PRIVATE KEY-----
+MIHcAgEBBEIBSNZKFcWzXzB/aJClAb305ibalKgtDA7+70eEkdPt28/3LZMM935Z
+KqYHh/COcxuu3Kt8azRAUz3gyr4zZKhlKUSgBwYFK4EEACOhgYkDgYYABAHUNKbx
+7JwC7H6pa2sV0tERWhHhB3JmW+OP6SUgMWryvIKajlx73eS24dy4QPGrWO9/ABsD
+FqcRSkNVTXnIv6+0mAF25knqIBIg5Q8M9BnOu9GGAchcwt3O7RDHmqewnJJDrbjd
+GGnm6rb+NnWR9DIopM0nKNkToWoF/hzopxu4Ae/GsQ==
+-----END EC PRIVATE KEY-----
+`
+	// 1. openssl ec -in key.pem -noout -text
+	// 2. remove first byte, 04 (the header); the rest is X and Y
+	// 3. convert each with: echo <val> | xxd -r -p | base64 -w 100 | tr -d '=' | tr '/+' '_-'
+	testKeyECPubX    = "5lhEug5xK4xBDZ2nAbaxLtaLiv85bxJ7ePd1dkO23HQ"
+	testKeyECPubY    = "4aiK72sBeUAGkv0TaLsmwokYUYyNxGsS5EMIKwsNIKk"
+	testKeyEC384PubX = "MyrY_jLNLx6E1-Xc79_y-WDFzlriOVCkYyYoKWoWAqlw9gQNY9BP9sbeb5T3_oJt"
+	testKeyEC384PubY = "Dy_lB0kLAqJBpyBrmhwrCQKd68tIB0BJHlmF2qVFBXb2itUdv9oZ-TvnokDPGMwo"
+	testKeyEC512PubX = "AdQ0pvHsnALsfqlraxXS0RFaEeEHcmZb44_pJSAxavK8gpqOXHvd5Lbh3LhA8atY738AGwMWpxFKQ1VNeci_r7SY"
+	testKeyEC512PubY = "AXbmSeogEiDlDwz0Gc670YYByFzC3c7tEMeap7CckkOtuN0Yaebqtv42dZH0MiikzSco2ROhagX-HOinG7gB78ax"
+
+	// echo -n '{"crv":"P-256","kty":"EC","x":"<testKeyECPubX>","y":"<testKeyECPubY>"}' | \
+	// openssl dgst -binary -sha256 | base64 | tr -d '=' | tr '/+' '_-'
+	testKeyECThumbprint = "zedj-Bd1Zshp8KLePv2MB-lJ_Hagp7wAwdkA0NUTniU"
+)
+
+var (
+	testKey      *rsa.PrivateKey
+	testKeyEC    *ecdsa.PrivateKey
+	testKeyEC384 *ecdsa.PrivateKey
+	testKeyEC512 *ecdsa.PrivateKey
+)
+
+func init() {
+	testKey = parseRSA(testKeyPEM, "testKeyPEM")
+	testKeyEC = parseEC(testKeyECPEM, "testKeyECPEM")
+	testKeyEC384 = parseEC(testKeyEC384PEM, "testKeyEC384PEM")
+	testKeyEC512 = parseEC(testKeyEC512PEM, "testKeyEC512PEM")
+}
+
+func decodePEM(s, name string) []byte {
+	d, _ := pem.Decode([]byte(s))
+	if d == nil {
+		panic("no block found in " + name)
+	}
+	return d.Bytes
+}
+
+func parseRSA(s, name string) *rsa.PrivateKey {
+	b := decodePEM(s, name)
+	k, err := x509.ParsePKCS1PrivateKey(b)
+	if err != nil {
+		panic(fmt.Sprintf("%s: %v", name, err))
+	}
+	return k
+}
+
+func parseEC(s, name string) *ecdsa.PrivateKey {
+	b := decodePEM(s, name)
+	k, err := x509.ParseECPrivateKey(b)
+	if err != nil {
+		panic(fmt.Sprintf("%s: %v", name, err))
+	}
+	return k
+}
+
+func TestJWSEncodeJSON(t *testing.T) {
+	claims := struct{ Msg string }{"Hello JWS"}
+	// JWS signed with testKey and "nonce" as the nonce value
+	// JSON-serialized JWS fields are split for easier testing
+	const (
+		// {"alg":"RS256","jwk":{"e":"AQAB","kty":"RSA","n":"..."},"nonce":"nonce"}
+		protected = "eyJhbGciOiJSUzI1NiIsImp3ayI6eyJlIjoiQVFBQiIsImt0eSI6" +
+			"IlJTQSIsIm4iOiI0eGdaM2VSUGt3b1J2eTdxZVJVYm1NRGUwVi14" +
+			"SDllV0xkdTBpaGVlTGxybUQybXFXWGZQOUllU0tBcGJuMzRnOFR1" +
+			"QVM5ZzV6aHE4RUxRM2ttanItS1Y4NkdBTWdJNlZBY0dscTNRcnpw" +
+			"VENmXzMwQWI3LXphd3JmUmFGT05hMUh3RXpQWTFLSG5HVmt4SmM4" +
+			"NWdOa3dZSTlTWTJSSFh0dmxuM3pzNXdJVE5yZG9zcUVYZWFJa1ZZ" +
+			"QkVoYmhOdTU0cHAza3hvNlR1V0xpOWU2cFhlV2V0RXdtbEJ3dFda" +
+			"bFBvaWIyajNUeExCa3NLWmZveUZ5ZWszODBtSGdKQXVtUV9JMmZq" +
+			"ajk4Xzk3bWszaWhPWTRBZ1ZkQ0RqMXpfR0NvWmtHNVJxN25iQ0d5" +
+			"b3N5S1d5RFgwMFpzLW5OcVZob0xlSXZYQzRubldkSk1aNnJvZ3h5" +
+			"UVEifSwibm9uY2UiOiJub25jZSJ9"
+		// {"Msg":"Hello JWS"}
+		payload   = "eyJNc2ciOiJIZWxsbyBKV1MifQ"
+		signature = "eAGUikStX_UxyiFhxSLMyuyBcIB80GeBkFROCpap2sW3EmkU_ggF" +
+			"knaQzxrTfItICSAXsCLIquZ5BbrSWA_4vdEYrwWtdUj7NqFKjHRa" +
+			"zpLHcoR7r1rEHvkoP1xj49lS5fc3Wjjq8JUhffkhGbWZ8ZVkgPdC" +
+			"4tMBWiQDoth-x8jELP_3LYOB_ScUXi2mETBawLgOT2K8rA0Vbbmx" +
+			"hWNlOWuUf-8hL5YX4IOEwsS8JK_TrTq5Zc9My0zHJmaieqDV0UlP" +
+			"k0onFjPFkGm7MrPSgd0MqRG-4vSAg2O4hDo7rKv4n8POjjXlNQvM" +
+			"9IPLr8qZ7usYBKhEGwX3yq_eicAwBw"
+	)
+
+	b, err := jwsEncodeJSON(claims, testKey, "nonce")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var jws struct{ Protected, Payload, Signature string }
+	if err := json.Unmarshal(b, &jws); err != nil {
+		t.Fatal(err)
+	}
+	if jws.Protected != protected {
+		t.Errorf("protected:\n%s\nwant:\n%s", jws.Protected, protected)
+	}
+	if jws.Payload != payload {
+		t.Errorf("payload:\n%s\nwant:\n%s", jws.Payload, payload)
+	}
+	if jws.Signature != signature {
+		t.Errorf("signature:\n%s\nwant:\n%s", jws.Signature, signature)
+	}
+}
+
+func TestJWSEncodeJSONEC(t *testing.T) {
+	tt := []struct {
+		key      *ecdsa.PrivateKey
+		x, y     string
+		alg, crv string
+	}{
+		{testKeyEC, testKeyECPubX, testKeyECPubY, "ES256", "P-256"},
+		{testKeyEC384, testKeyEC384PubX, testKeyEC384PubY, "ES384", "P-384"},
+		{testKeyEC512, testKeyEC512PubX, testKeyEC512PubY, "ES512", "P-521"},
+	}
+	for i, test := range tt {
+		claims := struct{ Msg string }{"Hello JWS"}
+		b, err := jwsEncodeJSON(claims, test.key, "nonce")
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+			continue
+		}
+		var jws struct{ Protected, Payload, Signature string }
+		if err := json.Unmarshal(b, &jws); err != nil {
+			t.Errorf("%d: %v", i, err)
+			continue
+		}
+
+		b, err = base64.RawURLEncoding.DecodeString(jws.Protected)
+		if err != nil {
+			t.Errorf("%d: jws.Protected: %v", i, err)
+		}
+		var head struct {
+			Alg   string
+			Nonce string
+			JWK   struct {
+				Crv string
+				Kty string
+				X   string
+				Y   string
+			} `json:"jwk"`
+		}
+		if err := json.Unmarshal(b, &head); err != nil {
+			t.Errorf("%d: jws.Protected: %v", i, err)
+		}
+		if head.Alg != test.alg {
+			t.Errorf("%d: head.Alg = %q; want %q", i, head.Alg, test.alg)
+		}
+		if head.Nonce != "nonce" {
+			t.Errorf("%d: head.Nonce = %q; want nonce", i, head.Nonce)
+		}
+		if head.JWK.Crv != test.crv {
+			t.Errorf("%d: head.JWK.Crv = %q; want %q", i, head.JWK.Crv, test.crv)
+		}
+		if head.JWK.Kty != "EC" {
+			t.Errorf("%d: head.JWK.Kty = %q; want EC", i, head.JWK.Kty)
+		}
+		if head.JWK.X != test.x {
+			t.Errorf("%d: head.JWK.X = %q; want %q", i, head.JWK.X, test.x)
+		}
+		if head.JWK.Y != test.y {
+			t.Errorf("%d: head.JWK.Y = %q; want %q", i, head.JWK.Y, test.y)
+		}
+	}
+}
+
+func TestJWKThumbprintRSA(t *testing.T) {
+	// Key example from RFC 7638
+	const base64N = "0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx4cbbfAAt" +
+		"VT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKRXjBZCiFV4n3oknjhMstn6" +
+		"4tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FD" +
+		"W2QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHzu6qMQvRL5hajrn1n9" +
+		"1CbOpbISD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINH" +
+		"aQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw"
+	const base64E = "AQAB"
+	const expected = "NzbLsXh8uDCcd-6MNwXF4W_7noWXFZAfHkxZsRGC9Xs"
+
+	b, err := base64.RawURLEncoding.DecodeString(base64N)
+	if err != nil {
+		t.Fatalf("Error parsing example key N: %v", err)
+	}
+	n := new(big.Int).SetBytes(b)
+
+	b, err = base64.RawURLEncoding.DecodeString(base64E)
+	if err != nil {
+		t.Fatalf("Error parsing example key E: %v", err)
+	}
+	e := new(big.Int).SetBytes(b)
+
+	pub := &rsa.PublicKey{N: n, E: int(e.Uint64())}
+	th, err := JWKThumbprint(pub)
+	if err != nil {
+		t.Error(err)
+	}
+	if th != expected {
+		t.Errorf("thumbprint = %q; want %q", th, expected)
+	}
+}
+
+func TestJWKThumbprintEC(t *testing.T) {
+	// Key example from RFC 7520
+	// expected was computed with
+	// echo -n '{"crv":"P-521","kty":"EC","x":"<base64X>","y":"<base64Y>"}' | \
+	// openssl dgst -binary -sha256 | \
+	// base64 | \
+	// tr -d '=' | tr '/+' '_-'
+	const (
+		base64X = "AHKZLLOsCOzz5cY97ewNUajB957y-C-U88c3v13nmGZx6sYl_oJXu9A5RkT" +
+			"KqjqvjyekWF-7ytDyRXYgCF5cj0Kt"
+		base64Y = "AdymlHvOiLxXkEhayXQnNCvDX4h9htZaCJN34kfmC6pV5OhQHiraVySsUda" +
+			"QkAgDPrwQrJmbnX9cwlGfP-HqHZR1"
+		expected = "dHri3SADZkrush5HU_50AoRhcKFryN-PI6jPBtPL55M"
+	)
+
+	b, err := base64.RawURLEncoding.DecodeString(base64X)
+	if err != nil {
+		t.Fatalf("Error parsing example key X: %v", err)
+	}
+	x := new(big.Int).SetBytes(b)
+
+	b, err = base64.RawURLEncoding.DecodeString(base64Y)
+	if err != nil {
+		t.Fatalf("Error parsing example key Y: %v", err)
+	}
+	y := new(big.Int).SetBytes(b)
+
+	pub := &ecdsa.PublicKey{Curve: elliptic.P521(), X: x, Y: y}
+	th, err := JWKThumbprint(pub)
+	if err != nil {
+		t.Error(err)
+	}
+	if th != expected {
+		t.Errorf("thumbprint = %q; want %q", th, expected)
+	}
+}
+
+func TestJWKThumbprintErrUnsupportedKey(t *testing.T) {
+	_, err := JWKThumbprint(struct{}{})
+	if err != ErrUnsupportedKey {
+		t.Errorf("err = %q; want %q", err, ErrUnsupportedKey)
+	}
+}

vendor/golang.org/x/crypto/acme/types.go

@@ -0,0 +1,329 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+	"crypto"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// ACME server response statuses used to describe Authorization and Challenge states.
+const (
+	StatusUnknown    = "unknown"
+	StatusPending    = "pending"
+	StatusProcessing = "processing"
+	StatusValid      = "valid"
+	StatusInvalid    = "invalid"
+	StatusRevoked    = "revoked"
+)
+
+// CRLReasonCode identifies the reason for a certificate revocation.
+type CRLReasonCode int
+
+// CRL reason codes as defined in RFC 5280.
+const (
+	CRLReasonUnspecified          CRLReasonCode = 0
+	CRLReasonKeyCompromise        CRLReasonCode = 1
+	CRLReasonCACompromise         CRLReasonCode = 2
+	CRLReasonAffiliationChanged   CRLReasonCode = 3
+	CRLReasonSuperseded           CRLReasonCode = 4
+	CRLReasonCessationOfOperation CRLReasonCode = 5
+	CRLReasonCertificateHold      CRLReasonCode = 6
+	CRLReasonRemoveFromCRL        CRLReasonCode = 8
+	CRLReasonPrivilegeWithdrawn   CRLReasonCode = 9
+	CRLReasonAACompromise         CRLReasonCode = 10
+)
+
+// ErrUnsupportedKey is returned when an unsupported key type is encountered.
+var ErrUnsupportedKey = errors.New("acme: unknown key type; only RSA and ECDSA are supported")
+
+// Error is an ACME error, defined in Problem Details for HTTP APIs doc
+// http://tools.ietf.org/html/draft-ietf-appsawg-http-problem.
+type Error struct {
+	// StatusCode is The HTTP status code generated by the origin server.
+	StatusCode int
+	// ProblemType is a URI reference that identifies the problem type,
+	// typically in a "urn:acme:error:xxx" form.
+	ProblemType string
+	// Detail is a human-readable explanation specific to this occurrence of the problem.
+	Detail string
+	// Header is the original server error response headers.
+	// It may be nil.
+	Header http.Header
+}
+
+func (e *Error) Error() string {
+	return fmt.Sprintf("%d %s: %s", e.StatusCode, e.ProblemType, e.Detail)
+}
+
+// AuthorizationError indicates that an authorization for an identifier
+// did not succeed.
+// It contains all errors from Challenge items of the failed Authorization.
+type AuthorizationError struct {
+	// URI uniquely identifies the failed Authorization.
+	URI string
+
+	// Identifier is an AuthzID.Value of the failed Authorization.
+	Identifier string
+
+	// Errors is a collection of non-nil error values of Challenge items
+	// of the failed Authorization.
+	Errors []error
+}
+
+func (a *AuthorizationError) Error() string {
+	e := make([]string, len(a.Errors))
+	for i, err := range a.Errors {
+		e[i] = err.Error()
+	}
+	return fmt.Sprintf("acme: authorization error for %s: %s", a.Identifier, strings.Join(e, "; "))
+}
+
+// RateLimit reports whether err represents a rate limit error and
+// any Retry-After duration returned by the server.
+//
+// See the following for more details on rate limiting:
+// https://tools.ietf.org/html/draft-ietf-acme-acme-05#section-5.6
+func RateLimit(err error) (time.Duration, bool) {
+	e, ok := err.(*Error)
+	if !ok {
+		return 0, false
+	}
+	// Some CA implementations may return incorrect values.
+	// Use case-insensitive comparison.
+	if !strings.HasSuffix(strings.ToLower(e.ProblemType), ":ratelimited") {
+		return 0, false
+	}
+	if e.Header == nil {
+		return 0, true
+	}
+	return retryAfter(e.Header.Get("Retry-After")), true
+}
+
+// Account is a user account. It is associated with a private key.
+type Account struct {
+	// URI is the account unique ID, which is also a URL used to retrieve
+	// account data from the CA.
+	URI string
+
+	// Contact is a slice of contact info used during registration.
+	Contact []string
+
+	// The terms user has agreed to.
+	// A value not matching CurrentTerms indicates that the user hasn't agreed
+	// to the actual Terms of Service of the CA.
+	AgreedTerms string
+
+	// Actual terms of a CA.
+	CurrentTerms string
+
+	// Authz is the authorization URL used to initiate a new authz flow.
+	Authz string
+
+	// Authorizations is a URI from which a list of authorizations
+	// granted to this account can be fetched via a GET request.
+	Authorizations string
+
+	// Certificates is a URI from which a list of certificates
+	// issued for this account can be fetched via a GET request.
+	Certificates string
+}
+
+// Directory is ACME server discovery data.
+type Directory struct {
+	// RegURL is an account endpoint URL, allowing for creating new
+	// and modifying existing accounts.
+	RegURL string
+
+	// AuthzURL is used to initiate Identifier Authorization flow.
+	AuthzURL string
+
+	// CertURL is a new certificate issuance endpoint URL.
+	CertURL string
+
+	// RevokeURL is used to initiate a certificate revocation flow.
+	RevokeURL string
+
+	// Term is a URI identifying the current terms of service.
+	Terms string
+
+	// Website is an HTTP or HTTPS URL locating a website
+	// providing more information about the ACME server.
+	Website string
+
+	// CAA consists of lowercase hostname elements, which the ACME server
+	// recognises as referring to itself for the purposes of CAA record validation
+	// as defined in RFC6844.
+	CAA []string
+}
+
+// Challenge encodes a returned CA challenge.
+// Its Error field may be non-nil if the challenge is part of an Authorization
+// with StatusInvalid.
+type Challenge struct {
+	// Type is the challenge type, e.g. "http-01", "tls-sni-02", "dns-01".
+	Type string
+
+	// URI is where a challenge response can be posted to.
+	URI string
+
+	// Token is a random value that uniquely identifies the challenge.
+	Token string
+
+	// Status identifies the status of this challenge.
+	Status string
+
+	// Error indicates the reason for an authorization failure
+	// when this challenge was used.
+	// The type of a non-nil value is *Error.
+	Error error
+}
+
+// Authorization encodes an authorization response.
+type Authorization struct {
+	// URI uniquely identifies a authorization.
+	URI string
+
+	// Status identifies the status of an authorization.
+	Status string
+
+	// Identifier is what the account is authorized to represent.
+	Identifier AuthzID
+
+	// Challenges that the client needs to fulfill in order to prove possession
+	// of the identifier (for pending authorizations).
+	// For final authorizations, the challenges that were used.
+	Challenges []*Challenge
+
+	// A collection of sets of challenges, each of which would be sufficient
+	// to prove possession of the identifier.
+	// Clients must complete a set of challenges that covers at least one set.
+	// Challenges are identified by their indices in the challenges array.
+	// If this field is empty, the client needs to complete all challenges.
+	Combinations [][]int
+}
+
+// AuthzID is an identifier that an account is authorized to represent.
+type AuthzID struct {
+	Type  string // The type of identifier, e.g. "dns".
+	Value string // The identifier itself, e.g. "example.org".
+}
+
+// wireAuthz is ACME JSON representation of Authorization objects.
+type wireAuthz struct {
+	Status       string
+	Challenges   []wireChallenge
+	Combinations [][]int
+	Identifier   struct {
+		Type  string
+		Value string
+	}
+}
+
+func (z *wireAuthz) authorization(uri string) *Authorization {
+	a := &Authorization{
+		URI:          uri,
+		Status:       z.Status,
+		Identifier:   AuthzID{Type: z.Identifier.Type, Value: z.Identifier.Value},
+		Combinations: z.Combinations, // shallow copy
+		Challenges:   make([]*Challenge, len(z.Challenges)),
+	}
+	for i, v := range z.Challenges {
+		a.Challenges[i] = v.challenge()
+	}
+	return a
+}
+
+func (z *wireAuthz) error(uri string) *AuthorizationError {
+	err := &AuthorizationError{
+		URI:        uri,
+		Identifier: z.Identifier.Value,
+	}
+	for _, raw := range z.Challenges {
+		if raw.Error != nil {
+			err.Errors = append(err.Errors, raw.Error.error(nil))
+		}
+	}
+	return err
+}
+
+// wireChallenge is ACME JSON challenge representation.
+type wireChallenge struct {
+	URI    string `json:"uri"`
+	Type   string
+	Token  string
+	Status string
+	Error  *wireError
+}
+
+func (c *wireChallenge) challenge() *Challenge {
+	v := &Challenge{
+		URI:    c.URI,
+		Type:   c.Type,
+		Token:  c.Token,
+		Status: c.Status,
+	}
+	if v.Status == "" {
+		v.Status = StatusPending
+	}
+	if c.Error != nil {
+		v.Error = c.Error.error(nil)
+	}
+	return v
+}
+
+// wireError is a subset of fields of the Problem Details object
+// as described in https://tools.ietf.org/html/rfc7807#section-3.1.
+type wireError struct {
+	Status int
+	Type   string
+	Detail string
+}
+
+func (e *wireError) error(h http.Header) *Error {
+	return &Error{
+		StatusCode:  e.Status,
+		ProblemType: e.Type,
+		Detail:      e.Detail,
+		Header:      h,
+	}
+}
+
+// CertOption is an optional argument type for the TLS ChallengeCert methods for
+// customizing a temporary certificate for TLS-based challenges.
+type CertOption interface {
+	privateCertOpt()
+}
+
+// WithKey creates an option holding a private/public key pair.
+// The private part signs a certificate, and the public part represents the signee.
+func WithKey(key crypto.Signer) CertOption {
+	return &certOptKey{key}
+}
+
+type certOptKey struct {
+	key crypto.Signer
+}
+
+func (*certOptKey) privateCertOpt() {}
+
+// WithTemplate creates an option for specifying a certificate template.
+// See x509.CreateCertificate for template usage details.
+//
+// In TLS ChallengeCert methods, the template is also used as parent,
+// resulting in a self-signed certificate.
+// The DNSNames field of t is always overwritten for tls-sni challenge certs.
+func WithTemplate(t *x509.Certificate) CertOption {
+	return (*certOptTemplate)(t)
+}
+
+type certOptTemplate x509.Certificate
+
+func (*certOptTemplate) privateCertOpt() {}

vendor/golang.org/x/crypto/acme/types_test.go

@@ -0,0 +1,63 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+	"errors"
+	"net/http"
+	"testing"
+	"time"
+)
+
+func TestRateLimit(t *testing.T) {
+	now := time.Date(2017, 04, 27, 10, 0, 0, 0, time.UTC)
+	f := timeNow
+	defer func() { timeNow = f }()
+	timeNow = func() time.Time { return now }
+
+	h120, hTime := http.Header{}, http.Header{}
+	h120.Set("Retry-After", "120")
+	hTime.Set("Retry-After", "Tue Apr 27 11:00:00 2017")
+
+	err1 := &Error{
+		ProblemType: "urn:ietf:params:acme:error:nolimit",
+		Header:      h120,
+	}
+	err2 := &Error{
+		ProblemType: "urn:ietf:params:acme:error:rateLimited",
+		Header:      h120,
+	}
+	err3 := &Error{
+		ProblemType: "urn:ietf:params:acme:error:rateLimited",
+		Header:      nil,
+	}
+	err4 := &Error{
+		ProblemType: "urn:ietf:params:acme:error:rateLimited",
+		Header:      hTime,
+	}
+
+	tt := []struct {
+		err error
+		res time.Duration
+		ok  bool
+	}{
+		{nil, 0, false},
+		{errors.New("dummy"), 0, false},
+		{err1, 0, false},
+		{err2, 2 * time.Minute, true},
+		{err3, 0, true},
+		{err4, time.Hour, true},
+	}
+	for i, test := range tt {
+		res, ok := RateLimit(test.err)
+		if ok != test.ok {
+			t.Errorf("%d: RateLimit(%+v): ok = %v; want %v", i, test.err, ok, test.ok)
+			continue
+		}
+		if res != test.res {
+			t.Errorf("%d: RateLimit(%+v) = %v; want %v", i, test.err, res, test.res)
+		}
+	}
+}