1066 lines
32 KiB
Go
1066 lines
32 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package acme provides an implementation of the
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// Automatic Certificate Management Environment (ACME) spec.
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// See https://tools.ietf.org/html/draft-ietf-acme-acme-02 for details.
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//
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// Most common scenarios will want to use autocert subdirectory instead,
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// which provides automatic access to certificates from Let's Encrypt
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// and any other ACME-based CA.
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//
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// This package is a work in progress and makes no API stability promises.
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package acme
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import (
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"bytes"
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"context"
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"crypto"
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"crypto/ecdsa"
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"crypto/elliptic"
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"crypto/rand"
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"crypto/sha256"
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"crypto/tls"
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"crypto/x509"
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"encoding/base64"
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"encoding/hex"
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"encoding/json"
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"encoding/pem"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"math/big"
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"net/http"
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"strconv"
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"strings"
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"sync"
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"time"
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)
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// LetsEncryptURL is the Directory endpoint of Let's Encrypt CA.
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const LetsEncryptURL = "https://acme-v01.api.letsencrypt.org/directory"
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const (
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maxChainLen = 5 // max depth and breadth of a certificate chain
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maxCertSize = 1 << 20 // max size of a certificate, in bytes
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// Max number of collected nonces kept in memory.
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// Expect usual peak of 1 or 2.
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maxNonces = 100
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)
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// Client is an ACME client.
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// The only required field is Key. An example of creating a client with a new key
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// is as follows:
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//
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// key, err := rsa.GenerateKey(rand.Reader, 2048)
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// if err != nil {
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// log.Fatal(err)
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// }
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// client := &Client{Key: key}
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//
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type Client struct {
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// Key is the account key used to register with a CA and sign requests.
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// Key.Public() must return a *rsa.PublicKey or *ecdsa.PublicKey.
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Key crypto.Signer
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// HTTPClient optionally specifies an HTTP client to use
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// instead of http.DefaultClient.
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HTTPClient *http.Client
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// DirectoryURL points to the CA directory endpoint.
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// If empty, LetsEncryptURL is used.
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// Mutating this value after a successful call of Client's Discover method
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// will have no effect.
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DirectoryURL string
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dirMu sync.Mutex // guards writes to dir
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dir *Directory // cached result of Client's Discover method
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noncesMu sync.Mutex
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nonces map[string]struct{} // nonces collected from previous responses
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}
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// Discover performs ACME server discovery using c.DirectoryURL.
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//
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// It caches successful result. So, subsequent calls will not result in
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// a network round-trip. This also means mutating c.DirectoryURL after successful call
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// of this method will have no effect.
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func (c *Client) Discover(ctx context.Context) (Directory, error) {
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c.dirMu.Lock()
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defer c.dirMu.Unlock()
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if c.dir != nil {
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return *c.dir, nil
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}
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dirURL := c.DirectoryURL
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if dirURL == "" {
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dirURL = LetsEncryptURL
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}
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res, err := c.get(ctx, dirURL)
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if err != nil {
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return Directory{}, err
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}
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defer res.Body.Close()
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c.addNonce(res.Header)
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if res.StatusCode != http.StatusOK {
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return Directory{}, responseError(res)
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}
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var v struct {
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Reg string `json:"new-reg"`
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Authz string `json:"new-authz"`
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Cert string `json:"new-cert"`
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Revoke string `json:"revoke-cert"`
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Meta struct {
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Terms string `json:"terms-of-service"`
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Website string `json:"website"`
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CAA []string `json:"caa-identities"`
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}
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}
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if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
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return Directory{}, err
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}
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c.dir = &Directory{
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RegURL: v.Reg,
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AuthzURL: v.Authz,
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CertURL: v.Cert,
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RevokeURL: v.Revoke,
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Terms: v.Meta.Terms,
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Website: v.Meta.Website,
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CAA: v.Meta.CAA,
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}
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return *c.dir, nil
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}
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// CreateCert requests a new certificate using the Certificate Signing Request csr encoded in DER format.
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// The exp argument indicates the desired certificate validity duration. CA may issue a certificate
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// with a different duration.
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// If the bundle argument is true, the returned value will also contain the CA (issuer) certificate chain.
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//
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// In the case where CA server does not provide the issued certificate in the response,
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// CreateCert will poll certURL using c.FetchCert, which will result in additional round-trips.
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// In such a scenario, the caller can cancel the polling with ctx.
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//
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// CreateCert returns an error if the CA's response or chain was unreasonably large.
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// Callers are encouraged to parse the returned value to ensure the certificate is valid and has the expected features.
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func (c *Client) CreateCert(ctx context.Context, csr []byte, exp time.Duration, bundle bool) (der [][]byte, certURL string, err error) {
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if _, err := c.Discover(ctx); err != nil {
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return nil, "", err
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}
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req := struct {
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Resource string `json:"resource"`
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CSR string `json:"csr"`
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NotBefore string `json:"notBefore,omitempty"`
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NotAfter string `json:"notAfter,omitempty"`
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}{
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Resource: "new-cert",
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CSR: base64.RawURLEncoding.EncodeToString(csr),
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}
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now := timeNow()
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req.NotBefore = now.Format(time.RFC3339)
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if exp > 0 {
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req.NotAfter = now.Add(exp).Format(time.RFC3339)
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}
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res, err := c.retryPostJWS(ctx, c.Key, c.dir.CertURL, req)
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if err != nil {
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return nil, "", err
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}
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defer res.Body.Close()
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if res.StatusCode != http.StatusCreated {
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return nil, "", responseError(res)
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}
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curl := res.Header.Get("Location") // cert permanent URL
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if res.ContentLength == 0 {
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// no cert in the body; poll until we get it
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cert, err := c.FetchCert(ctx, curl, bundle)
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return cert, curl, err
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}
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// slurp issued cert and CA chain, if requested
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cert, err := c.responseCert(ctx, res, bundle)
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return cert, curl, err
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}
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// FetchCert retrieves already issued certificate from the given url, in DER format.
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// It retries the request until the certificate is successfully retrieved,
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// context is cancelled by the caller or an error response is received.
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//
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// The returned value will also contain the CA (issuer) certificate if the bundle argument is true.
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//
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// FetchCert returns an error if the CA's response or chain was unreasonably large.
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// Callers are encouraged to parse the returned value to ensure the certificate is valid
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// and has expected features.
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func (c *Client) FetchCert(ctx context.Context, url string, bundle bool) ([][]byte, error) {
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for {
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res, err := c.get(ctx, url)
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if err != nil {
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return nil, err
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}
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defer res.Body.Close()
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if res.StatusCode == http.StatusOK {
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return c.responseCert(ctx, res, bundle)
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}
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if res.StatusCode > 299 {
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return nil, responseError(res)
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}
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d := retryAfter(res.Header.Get("Retry-After"), 3*time.Second)
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select {
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case <-time.After(d):
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// retry
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case <-ctx.Done():
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return nil, ctx.Err()
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}
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}
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}
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// RevokeCert revokes a previously issued certificate cert, provided in DER format.
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//
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// The key argument, used to sign the request, must be authorized
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// to revoke the certificate. It's up to the CA to decide which keys are authorized.
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// For instance, the key pair of the certificate may be authorized.
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// If the key is nil, c.Key is used instead.
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func (c *Client) RevokeCert(ctx context.Context, key crypto.Signer, cert []byte, reason CRLReasonCode) error {
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if _, err := c.Discover(ctx); err != nil {
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return err
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}
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body := &struct {
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Resource string `json:"resource"`
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Cert string `json:"certificate"`
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Reason int `json:"reason"`
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}{
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Resource: "revoke-cert",
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Cert: base64.RawURLEncoding.EncodeToString(cert),
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Reason: int(reason),
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}
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if key == nil {
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key = c.Key
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}
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res, err := c.retryPostJWS(ctx, key, c.dir.RevokeURL, body)
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if err != nil {
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return err
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}
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defer res.Body.Close()
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if res.StatusCode != http.StatusOK {
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return responseError(res)
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}
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return nil
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}
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// AcceptTOS always returns true to indicate the acceptance of a CA's Terms of Service
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// during account registration. See Register method of Client for more details.
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func AcceptTOS(tosURL string) bool { return true }
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// Register creates a new account registration by following the "new-reg" flow.
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// It returns the registered account. The account is not modified.
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//
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// The registration may require the caller to agree to the CA's Terms of Service (TOS).
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// If so, and the account has not indicated the acceptance of the terms (see Account for details),
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// Register calls prompt with a TOS URL provided by the CA. Prompt should report
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// whether the caller agrees to the terms. To always accept the terms, the caller can use AcceptTOS.
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func (c *Client) Register(ctx context.Context, a *Account, prompt func(tosURL string) bool) (*Account, error) {
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if _, err := c.Discover(ctx); err != nil {
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return nil, err
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}
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var err error
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if a, err = c.doReg(ctx, c.dir.RegURL, "new-reg", a); err != nil {
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return nil, err
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}
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var accept bool
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if a.CurrentTerms != "" && a.CurrentTerms != a.AgreedTerms {
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accept = prompt(a.CurrentTerms)
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}
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if accept {
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a.AgreedTerms = a.CurrentTerms
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a, err = c.UpdateReg(ctx, a)
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}
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return a, err
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}
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// GetReg retrieves an existing registration.
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// The url argument is an Account URI.
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func (c *Client) GetReg(ctx context.Context, url string) (*Account, error) {
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a, err := c.doReg(ctx, url, "reg", nil)
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if err != nil {
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return nil, err
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}
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a.URI = url
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return a, nil
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}
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// UpdateReg updates an existing registration.
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// It returns an updated account copy. The provided account is not modified.
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func (c *Client) UpdateReg(ctx context.Context, a *Account) (*Account, error) {
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uri := a.URI
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a, err := c.doReg(ctx, uri, "reg", a)
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if err != nil {
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return nil, err
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}
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a.URI = uri
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return a, nil
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}
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// Authorize performs the initial step in an authorization flow.
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// The caller will then need to choose from and perform a set of returned
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// challenges using c.Accept in order to successfully complete authorization.
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//
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// If an authorization has been previously granted, the CA may return
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// a valid authorization (Authorization.Status is StatusValid). If so, the caller
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// need not fulfill any challenge and can proceed to requesting a certificate.
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func (c *Client) Authorize(ctx context.Context, domain string) (*Authorization, error) {
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if _, err := c.Discover(ctx); err != nil {
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return nil, err
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}
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type authzID struct {
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Type string `json:"type"`
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Value string `json:"value"`
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}
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req := struct {
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Resource string `json:"resource"`
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Identifier authzID `json:"identifier"`
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}{
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Resource: "new-authz",
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Identifier: authzID{Type: "dns", Value: domain},
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}
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res, err := c.retryPostJWS(ctx, c.Key, c.dir.AuthzURL, req)
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if err != nil {
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return nil, err
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}
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defer res.Body.Close()
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if res.StatusCode != http.StatusCreated {
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return nil, responseError(res)
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}
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var v wireAuthz
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if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
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return nil, fmt.Errorf("acme: invalid response: %v", err)
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}
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if v.Status != StatusPending && v.Status != StatusValid {
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return nil, fmt.Errorf("acme: unexpected status: %s", v.Status)
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}
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return v.authorization(res.Header.Get("Location")), nil
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}
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// GetAuthorization retrieves an authorization identified by the given URL.
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//
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// If a caller needs to poll an authorization until its status is final,
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// see the WaitAuthorization method.
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func (c *Client) GetAuthorization(ctx context.Context, url string) (*Authorization, error) {
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res, err := c.get(ctx, url)
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if err != nil {
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return nil, err
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}
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defer res.Body.Close()
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if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
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return nil, responseError(res)
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}
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var v wireAuthz
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if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
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return nil, fmt.Errorf("acme: invalid response: %v", err)
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}
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return v.authorization(url), nil
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}
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// RevokeAuthorization relinquishes an existing authorization identified
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// by the given URL.
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// The url argument is an Authorization.URI value.
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//
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// If successful, the caller will be required to obtain a new authorization
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// using the Authorize method before being able to request a new certificate
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// for the domain associated with the authorization.
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//
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// It does not revoke existing certificates.
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func (c *Client) RevokeAuthorization(ctx context.Context, url string) error {
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req := struct {
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Resource string `json:"resource"`
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Status string `json:"status"`
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Delete bool `json:"delete"`
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}{
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Resource: "authz",
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Status: "deactivated",
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Delete: true,
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}
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res, err := c.retryPostJWS(ctx, c.Key, url, req)
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if err != nil {
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return err
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}
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defer res.Body.Close()
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if res.StatusCode != http.StatusOK {
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return responseError(res)
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}
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return nil
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}
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// WaitAuthorization polls an authorization at the given URL
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// until it is in one of the final states, StatusValid or StatusInvalid,
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// the ACME CA responded with a 4xx error code, or the context is done.
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//
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// It returns a non-nil Authorization only if its Status is StatusValid.
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// In all other cases WaitAuthorization returns an error.
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// If the Status is StatusInvalid, the returned error is of type *AuthorizationError.
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func (c *Client) WaitAuthorization(ctx context.Context, url string) (*Authorization, error) {
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sleep := sleeper(ctx)
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for {
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res, err := c.get(ctx, url)
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if err != nil {
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return nil, err
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}
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if res.StatusCode >= 400 && res.StatusCode <= 499 {
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// Non-retriable error. For instance, Let's Encrypt may return 404 Not Found
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// when requesting an expired authorization.
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defer res.Body.Close()
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return nil, responseError(res)
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}
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retry := res.Header.Get("Retry-After")
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if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
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res.Body.Close()
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if err := sleep(retry, 1); err != nil {
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return nil, err
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}
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continue
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}
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var raw wireAuthz
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err = json.NewDecoder(res.Body).Decode(&raw)
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res.Body.Close()
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if err != nil {
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if err := sleep(retry, 0); err != nil {
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return nil, err
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}
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continue
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}
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if raw.Status == StatusValid {
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return raw.authorization(url), nil
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}
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if raw.Status == StatusInvalid {
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return nil, raw.error(url)
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}
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if err := sleep(retry, 0); err != nil {
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return nil, err
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}
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}
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}
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// GetChallenge retrieves the current status of an challenge.
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//
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// A client typically polls a challenge status using this method.
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func (c *Client) GetChallenge(ctx context.Context, url string) (*Challenge, error) {
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res, err := c.get(ctx, url)
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if err != nil {
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return nil, err
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}
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defer res.Body.Close()
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if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
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return nil, responseError(res)
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}
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v := wireChallenge{URI: url}
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if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
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return nil, fmt.Errorf("acme: invalid response: %v", err)
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}
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return v.challenge(), nil
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}
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// Accept informs the server that the client accepts one of its challenges
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// previously obtained with c.Authorize.
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//
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// The server will then perform the validation asynchronously.
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func (c *Client) Accept(ctx context.Context, chal *Challenge) (*Challenge, error) {
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auth, err := keyAuth(c.Key.Public(), chal.Token)
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if err != nil {
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return nil, err
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}
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req := struct {
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Resource string `json:"resource"`
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Type string `json:"type"`
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Auth string `json:"keyAuthorization"`
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}{
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Resource: "challenge",
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Type: chal.Type,
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Auth: auth,
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}
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res, err := c.retryPostJWS(ctx, c.Key, chal.URI, req)
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if err != nil {
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return nil, err
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}
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defer res.Body.Close()
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// Note: the protocol specifies 200 as the expected response code, but
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// letsencrypt seems to be returning 202.
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if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusAccepted {
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return nil, responseError(res)
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}
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var v wireChallenge
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if err := json.NewDecoder(res.Body).Decode(&v); err != nil {
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return nil, fmt.Errorf("acme: invalid response: %v", err)
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}
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return v.challenge(), nil
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}
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// DNS01ChallengeRecord returns a DNS record value for a dns-01 challenge response.
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// A TXT record containing the returned value must be provisioned under
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// "_acme-challenge" name of the domain being validated.
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//
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// The token argument is a Challenge.Token value.
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func (c *Client) DNS01ChallengeRecord(token string) (string, error) {
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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.
|
|
// 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 *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
|
|
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
|