--- /dev/null
+// 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 (
+ "bytes"
+ "context"
+ "crypto"
+ "crypto/ecdsa"
+ "crypto/elliptic"
+ "crypto/rand"
+ "crypto/sha256"
+ "crypto/tls"
+ "crypto/x509"
+ "encoding/base64"
+ "encoding/hex"
+ "encoding/json"
+ "encoding/pem"
+ "errors"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "math/big"
+ "net/http"
+ "strconv"
+ "strings"
+ "sync"
+ "time"
+)
+
+// LetsEncryptURL is the Directory endpoint of Let's Encrypt CA.
+const LetsEncryptURL = "https://acme-v01.api.letsencrypt.org/directory"
+
+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
+)
+
+// CertOption is an optional argument type for Client methods which manipulate
+// certificate data.
+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 TLSSNIxChallengeCert 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() {}
+
+// 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
+
+ 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)
+ if err != nil {
+ return Directory{}, err
+ }
+ defer res.Body.Close()
+ c.addNonce(res.Header)
+ if res.StatusCode != http.StatusOK {
+ return Directory{}, responseError(res)
+ }
+
+ 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 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.retryPostJWS(ctx, c.Key, c.dir.CertURL, req)
+ if err != nil {
+ return nil, "", err
+ }
+ defer res.Body.Close()
+ if res.StatusCode != http.StatusCreated {
+ return nil, "", responseError(res)
+ }
+
+ 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) {
+ for {
+ res, err := c.get(ctx, url)
+ if err != nil {
+ return nil, err
+ }
+ defer res.Body.Close()
+ if res.StatusCode == http.StatusOK {
+ return c.responseCert(ctx, res, bundle)
+ }
+ if res.StatusCode > 299 {
+ return nil, responseError(res)
+ }
+ d := retryAfter(res.Header.Get("Retry-After"), 3*time.Second)
+ select {
+ case <-time.After(d):
+ // retry
+ case <-ctx.Done():
+ return nil, ctx.Err()
+ }
+ }
+}
+
+// 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.retryPostJWS(ctx, key, c.dir.RevokeURL, body)
+ if err != nil {
+ return err
+ }
+ defer res.Body.Close()
+ if res.StatusCode != http.StatusOK {
+ return responseError(res)
+ }
+ 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 registered account. The a argument 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.retryPostJWS(ctx, c.Key, c.dir.AuthzURL, req)
+ if err != nil {
+ return nil, err
+ }
+ defer res.Body.Close()
+ if res.StatusCode != http.StatusCreated {
+ return nil, responseError(res)
+ }
+
+ 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)
+ if err != nil {
+ return nil, err
+ }
+ defer res.Body.Close()
+ if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
+ return nil, responseError(res)
+ }
+ 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.retryPostJWS(ctx, c.Key, url, req)
+ if err != nil {
+ return err
+ }
+ defer res.Body.Close()
+ if res.StatusCode != http.StatusOK {
+ return responseError(res)
+ }
+ return nil
+}
+
+// WaitAuthorization polls an authorization at the given URL
+// until it is in one of the final states, StatusValid or StatusInvalid,
+// 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) {
+ sleep := sleeper(ctx)
+ for {
+ res, err := c.get(ctx, url)
+ if err != nil {
+ return nil, err
+ }
+ retry := res.Header.Get("Retry-After")
+ if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
+ res.Body.Close()
+ if err := sleep(retry, 1); err != nil {
+ return nil, err
+ }
+ continue
+ }
+ var raw wireAuthz
+ err = json.NewDecoder(res.Body).Decode(&raw)
+ res.Body.Close()
+ if err != nil {
+ if err := sleep(retry, 0); err != nil {
+ return nil, err
+ }
+ continue
+ }
+ if raw.Status == StatusValid {
+ return raw.authorization(url), nil
+ }
+ if raw.Status == StatusInvalid {
+ return nil, raw.error(url)
+ }
+ if err := sleep(retry, 0); err != nil {
+ return nil, err
+ }
+ }
+}
+
+// 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)
+ if err != nil {
+ return nil, err
+ }
+ defer res.Body.Close()
+ if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
+ return nil, responseError(res)
+ }
+ 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.retryPostJWS(ctx, c.Key, chal.URI, req)
+ if err != nil {
+ return nil, err
+ }
+ defer res.Body.Close()
+ // Note: the protocol specifies 200 as the expected response code, but
+ // letsencrypt seems to be returning 202.
+ if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
+ return nil, responseError(res)
+ }
+
+ 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 client hello 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 client hello 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
+}
+
+// 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.retryPostJWS(ctx, c.Key, url, req)
+ if err != nil {
+ return nil, err
+ }
+ defer res.Body.Close()
+ if res.StatusCode < 200 || res.StatusCode > 299 {
+ return nil, responseError(res)
+ }
+
+ 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
+}
+
+// retryPostJWS will retry calls to postJWS if there is a badNonce error,
+// clearing the stored nonces after each error.
+// If the response was 4XX-5XX, then responseError is called on the body,
+// the body is closed, and the error returned.
+func (c *Client) retryPostJWS(ctx context.Context, key crypto.Signer, url string, body interface{}) (*http.Response, error) {
+ sleep := sleeper(ctx)
+ for {
+ res, err := c.postJWS(ctx, key, url, body)
+ if err != nil {
+ return nil, err
+ }
+ // handle errors 4XX-5XX with responseError
+ if res.StatusCode >= 400 && res.StatusCode <= 599 {
+ err := responseError(res)
+ res.Body.Close()
+ // according to spec badNonce is urn:ietf:params:acme:error:badNonce
+ // however, acme servers in the wild return their version of the error
+ // https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-5.4
+ if ae, ok := err.(*Error); ok && strings.HasSuffix(strings.ToLower(ae.ProblemType), ":badnonce") {
+ // clear any nonces that we might've stored that might now be
+ // considered bad
+ c.clearNonces()
+ retry := res.Header.Get("Retry-After")
+ if err := sleep(retry, 1); err != nil {
+ return nil, err
+ }
+ continue
+ }
+ return nil, err
+ }
+ return res, nil
+ }
+}
+
+// postJWS signs the body with the given key and POSTs it to the provided url.
+// The body argument must be JSON-serializable.
+func (c *Client) postJWS(ctx context.Context, key crypto.Signer, url string, body interface{}) (*http.Response, error) {
+ nonce, err := c.popNonce(ctx, url)
+ if err != nil {
+ return nil, err
+ }
+ b, err := jwsEncodeJSON(body, key, nonce)
+ if err != nil {
+ return nil, err
+ }
+ res, err := c.post(ctx, url, "application/jose+json", bytes.NewReader(b))
+ if err != nil {
+ return nil, err
+ }
+ c.addNonce(res.Header)
+ return res, 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) httpClient() *http.Client {
+ if c.HTTPClient != nil {
+ return c.HTTPClient
+ }
+ return http.DefaultClient
+}
+
+func (c *Client) get(ctx context.Context, urlStr string) (*http.Response, error) {
+ req, err := http.NewRequest("GET", urlStr, nil)
+ if err != nil {
+ return nil, err
+ }
+ return c.do(ctx, req)
+}
+
+func (c *Client) head(ctx context.Context, urlStr string) (*http.Response, error) {
+ req, err := http.NewRequest("HEAD", urlStr, nil)
+ if err != nil {
+ return nil, err
+ }
+ return c.do(ctx, req)
+}
+
+func (c *Client) post(ctx context.Context, urlStr, contentType string, body io.Reader) (*http.Response, error) {
+ req, err := http.NewRequest("POST", urlStr, body)
+ if err != nil {
+ return nil, err
+ }
+ req.Header.Set("Content-Type", contentType)
+ return c.do(ctx, req)
+}
+
+func (c *Client) do(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) fetchNonce(ctx context.Context, url string) (string, error) {
+ resp, err := c.head(ctx, url)
+ 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
+}
+
+// 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)
+}
+
+// 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)
+ if err != nil {
+ return nil, err
+ }
+ defer res.Body.Close()
+ if res.StatusCode != http.StatusOK {
+ return nil, responseError(res)
+ }
+ 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
+}
+
+// sleeper returns a function that accepts the Retry-After HTTP header value
+// and an increment that's used with backoff to increasingly sleep on
+// consecutive calls until the context is done. If the Retry-After header
+// cannot be parsed, then backoff is used with a maximum sleep time of 10
+// seconds.
+func sleeper(ctx context.Context) func(ra string, inc int) error {
+ var count int
+ return func(ra string, inc int) error {
+ count += inc
+ d := backoff(count, 10*time.Second)
+ d = retryAfter(ra, d)
+ wakeup := time.NewTimer(d)
+ defer wakeup.Stop()
+ select {
+ case <-ctx.Done():
+ return ctx.Err()
+ case <-wakeup.C:
+ return nil
+ }
+ }
+}
+
+// retryAfter parses a Retry-After HTTP header value,
+// trying to convert v into an int (seconds) or use http.ParseTime otherwise.
+// It returns d if v cannot be parsed.
+func retryAfter(v string, d time.Duration) 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 d
+ }
+ return t.Sub(timeNow())
+}
+
+// backoff computes a duration after which an n+1 retry iteration should occur
+// using truncated exponential backoff algorithm.
+//
+// The n argument is always bounded between 0 and 30.
+// The max argument defines upper bound for the returned value.
+func backoff(n int, max time.Duration) time.Duration {
+ if n < 0 {
+ n = 0
+ }
+ if n > 30 {
+ n = 30
+ }
+ var d time.Duration
+ if x, err := rand.Int(rand.Reader, big.NewInt(1000)); err == nil {
+ d = time.Duration(x.Int64()) * time.Millisecond
+ }
+ d += time.Duration(1<<uint(n)) * time.Second
+ if d > max {
+ return max
+ }
+ return d
+}
+
+// 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
+}
+
+// tlsChallengeCert creates a temporary certificate for TLS-SNI challenges
+// with the given SANs and auto-generated public/private key pair.
+// 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 *x509.Certificate
+ )
+ 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:
+ var 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
+ }
+ }
+ if tmpl == nil {
+ tmpl = &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},
+ }
+ }
+ tmpl.DNSNames = san
+
+ 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
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