Merge pull request #2301 from jhernandezb/feature/acme-http-01

migrate to http-01 challenge
This commit is contained in:
Brad Rydzewski 2018-01-15 17:00:25 -08:00 committed by GitHub
commit 4db23fae05
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
5 changed files with 307 additions and 148 deletions

View file

@ -576,24 +576,23 @@ func server(c *cli.Context) error {
// start the server with lets encrypt enabled
// listen on ports 443 and 80
address, err := url.Parse(c.String("server-host"))
if err != nil {
return err
}
dir := cacheDir()
os.MkdirAll(dir, 0700)
manager := autocert.Manager{
Prompt: autocert.AcceptTOS,
HostPolicy: autocert.HostWhitelist(address.Host),
Cache: autocert.DirCache(dir),
}
g.Go(func() error {
return http.ListenAndServe(":http", http.HandlerFunc(redirect))
return http.ListenAndServe(":http", manager.HTTPHandler(http.HandlerFunc(redirect)))
})
g.Go(func() error {
address, err := url.Parse(c.String("server-host"))
if err != nil {
return err
}
dir := cacheDir()
os.MkdirAll(dir, 0700)
manager := autocert.Manager{
Prompt: autocert.AcceptTOS,
HostPolicy: autocert.HostWhitelist(address.Host),
Cache: autocert.DirCache(dir),
}
serve := &http.Server{
Addr: ":https",
Handler: handler,

View file

@ -51,38 +51,6 @@ const (
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:
@ -174,7 +142,7 @@ func (c *Client) Discover(ctx context.Context) (Directory, error) {
//
// 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.
// In such a scenario, the caller can cancel the polling with ctx.
//
// CreateCert returns an error if the CA's response or chain was unreasonably large.
// Callers are encouraged to parse the returned value to ensure the certificate is valid and has the expected features.
@ -289,7 +257,7 @@ func (c *Client) RevokeCert(ctx context.Context, key crypto.Signer, cert []byte,
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.
// It returns the registered account. The account is not modified.
//
// The registration may require the caller to agree to the CA's Terms of Service (TOS).
// If so, and the account has not indicated the acceptance of the terms (see Account for details),
@ -1027,6 +995,7 @@ func keyAuth(pub crypto.PublicKey, token string) (string, error) {
// 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 (
@ -1065,6 +1034,9 @@ func tlsChallengeCert(san []string, opt []CertOption) (tls.Certificate, error) {
}
}
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 {

View file

@ -24,7 +24,9 @@ import (
"fmt"
"io"
mathrand "math/rand"
"net"
"net/http"
"path"
"strconv"
"strings"
"sync"
@ -80,11 +82,14 @@ func defaultHostPolicy(context.Context, string) error {
}
// Manager is a stateful certificate manager built on top of acme.Client.
// It obtains and refreshes certificates automatically,
// as well as providing them to a TLS server via tls.Config.
// It obtains and refreshes certificates automatically using "tls-sni-01",
// "tls-sni-02" and "http-01" challenge types, as well as providing them
// to a TLS server via tls.Config.
//
// To preserve issued certificates and improve overall performance,
// use a cache implementation of Cache. For instance, DirCache.
// You must specify a cache implementation, such as DirCache,
// to reuse obtained certificates across program restarts.
// Otherwise your server is very likely to exceed the certificate
// issuer's request rate limits.
type Manager struct {
// Prompt specifies a callback function to conditionally accept a CA's Terms of Service (TOS).
// The registration may require the caller to agree to the CA's TOS.
@ -148,15 +153,26 @@ type Manager struct {
stateMu sync.Mutex
state map[string]*certState // keyed by domain name
// tokenCert is keyed by token domain name, which matches server name
// of ClientHello. Keys always have ".acme.invalid" suffix.
tokenCertMu sync.RWMutex
tokenCert map[string]*tls.Certificate
// renewal tracks the set of domains currently running renewal timers.
// It is keyed by domain name.
renewalMu sync.Mutex
renewal map[string]*domainRenewal
// tokensMu guards the rest of the fields: tryHTTP01, certTokens and httpTokens.
tokensMu sync.RWMutex
// tryHTTP01 indicates whether the Manager should try "http-01" challenge type
// during the authorization flow.
tryHTTP01 bool
// httpTokens contains response body values for http-01 challenges
// and is keyed by the URL path at which a challenge response is expected
// to be provisioned.
// The entries are stored for the duration of the authorization flow.
httpTokens map[string][]byte
// certTokens contains temporary certificates for tls-sni challenges
// and is keyed by token domain name, which matches server name of ClientHello.
// Keys always have ".acme.invalid" suffix.
// The entries are stored for the duration of the authorization flow.
certTokens map[string]*tls.Certificate
}
// GetCertificate implements the tls.Config.GetCertificate hook.
@ -183,14 +199,16 @@ func (m *Manager) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate,
return nil, errors.New("acme/autocert: server name contains invalid character")
}
// In the worst-case scenario, the timeout needs to account for caching, host policy,
// domain ownership verification and certificate issuance.
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
defer cancel()
// check whether this is a token cert requested for TLS-SNI challenge
if strings.HasSuffix(name, ".acme.invalid") {
m.tokenCertMu.RLock()
defer m.tokenCertMu.RUnlock()
if cert := m.tokenCert[name]; cert != nil {
m.tokensMu.RLock()
defer m.tokensMu.RUnlock()
if cert := m.certTokens[name]; cert != nil {
return cert, nil
}
if cert, err := m.cacheGet(ctx, name); err == nil {
@ -222,6 +240,68 @@ func (m *Manager) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate,
return cert, nil
}
// HTTPHandler configures the Manager to provision ACME "http-01" challenge responses.
// It returns an http.Handler that responds to the challenges and must be
// running on port 80. If it receives a request that is not an ACME challenge,
// it delegates the request to the optional fallback handler.
//
// If fallback is nil, the returned handler redirects all GET and HEAD requests
// to the default TLS port 443 with 302 Found status code, preserving the original
// request path and query. It responds with 400 Bad Request to all other HTTP methods.
// The fallback is not protected by the optional HostPolicy.
//
// Because the fallback handler is run with unencrypted port 80 requests,
// the fallback should not serve TLS-only requests.
//
// If HTTPHandler is never called, the Manager will only use TLS SNI
// challenges for domain verification.
func (m *Manager) HTTPHandler(fallback http.Handler) http.Handler {
m.tokensMu.Lock()
defer m.tokensMu.Unlock()
m.tryHTTP01 = true
if fallback == nil {
fallback = http.HandlerFunc(handleHTTPRedirect)
}
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if !strings.HasPrefix(r.URL.Path, "/.well-known/acme-challenge/") {
fallback.ServeHTTP(w, r)
return
}
// A reasonable context timeout for cache and host policy only,
// because we don't wait for a new certificate issuance here.
ctx, cancel := context.WithTimeout(r.Context(), time.Minute)
defer cancel()
if err := m.hostPolicy()(ctx, r.Host); err != nil {
http.Error(w, err.Error(), http.StatusForbidden)
return
}
data, err := m.httpToken(ctx, r.URL.Path)
if err != nil {
http.Error(w, err.Error(), http.StatusNotFound)
return
}
w.Write(data)
})
}
func handleHTTPRedirect(w http.ResponseWriter, r *http.Request) {
if r.Method != "GET" && r.Method != "HEAD" {
http.Error(w, "Use HTTPS", http.StatusBadRequest)
return
}
target := "https://" + stripPort(r.Host) + r.URL.RequestURI()
http.Redirect(w, r, target, http.StatusFound)
}
func stripPort(hostport string) string {
host, _, err := net.SplitHostPort(hostport)
if err != nil {
return hostport
}
return net.JoinHostPort(host, "443")
}
// cert returns an existing certificate either from m.state or cache.
// If a certificate is found in cache but not in m.state, the latter will be filled
// with the cached value.
@ -369,7 +449,7 @@ func (m *Manager) createCert(ctx context.Context, domain string) (*tls.Certifica
// We are the first; state is locked.
// Unblock the readers when domain ownership is verified
// and the we got the cert or the process failed.
// and we got the cert or the process failed.
defer state.Unlock()
state.locked = false
@ -437,16 +517,17 @@ func (m *Manager) certState(domain string) (*certState, error) {
return state, nil
}
// authorizedCert starts domain ownership verification process and requests a new cert upon success.
// authorizedCert starts the domain ownership verification process and requests a new cert upon success.
// The key argument is the certificate private key.
func (m *Manager) authorizedCert(ctx context.Context, key crypto.Signer, domain string) (der [][]byte, leaf *x509.Certificate, err error) {
if err := m.verify(ctx, domain); err != nil {
return nil, nil, err
}
client, err := m.acmeClient(ctx)
if err != nil {
return nil, nil, err
}
if err := m.verify(ctx, client, domain); err != nil {
return nil, nil, err
}
csr, err := certRequest(key, domain)
if err != nil {
return nil, nil, err
@ -462,98 +543,171 @@ func (m *Manager) authorizedCert(ctx context.Context, key crypto.Signer, domain
return der, leaf, nil
}
// verify starts a new identifier (domain) authorization flow.
// It prepares a challenge response and then blocks until the authorization
// is marked as "completed" by the CA (either succeeded or failed).
//
// verify returns nil iff the verification was successful.
func (m *Manager) verify(ctx context.Context, domain string) error {
client, err := m.acmeClient(ctx)
if err != nil {
return err
// verify runs the identifier (domain) authorization flow
// using each applicable ACME challenge type.
func (m *Manager) verify(ctx context.Context, client *acme.Client, domain string) error {
// The list of challenge types we'll try to fulfill
// in this specific order.
challengeTypes := []string{"tls-sni-02", "tls-sni-01"}
m.tokensMu.RLock()
if m.tryHTTP01 {
challengeTypes = append(challengeTypes, "http-01")
}
m.tokensMu.RUnlock()
// start domain authorization and get the challenge
authz, err := client.Authorize(ctx, domain)
if err != nil {
return err
}
// maybe don't need to at all
if authz.Status == acme.StatusValid {
return nil
}
// pick a challenge: prefer tls-sni-02 over tls-sni-01
// TODO: consider authz.Combinations
var chal *acme.Challenge
for _, c := range authz.Challenges {
if c.Type == "tls-sni-02" {
chal = c
break
var nextTyp int // challengeType index of the next challenge type to try
for {
// Start domain authorization and get the challenge.
authz, err := client.Authorize(ctx, domain)
if err != nil {
return err
}
if c.Type == "tls-sni-01" {
chal = c
// No point in accepting challenges if the authorization status
// is in a final state.
switch authz.Status {
case acme.StatusValid:
return nil // already authorized
case acme.StatusInvalid:
return fmt.Errorf("acme/autocert: invalid authorization %q", authz.URI)
}
// Pick the next preferred challenge.
var chal *acme.Challenge
for chal == nil && nextTyp < len(challengeTypes) {
chal = pickChallenge(challengeTypes[nextTyp], authz.Challenges)
nextTyp++
}
if chal == nil {
return fmt.Errorf("acme/autocert: unable to authorize %q; tried %q", domain, challengeTypes)
}
cleanup, err := m.fulfill(ctx, client, chal)
if err != nil {
continue
}
defer cleanup()
if _, err := client.Accept(ctx, chal); err != nil {
continue
}
// A challenge is fulfilled and accepted: wait for the CA to validate.
if _, err := client.WaitAuthorization(ctx, authz.URI); err == nil {
return nil
}
}
if chal == nil {
return errors.New("acme/autocert: no supported challenge type found")
}
// create a token cert for the challenge response
var (
cert tls.Certificate
name string
)
switch chal.Type {
case "tls-sni-01":
cert, name, err = client.TLSSNI01ChallengeCert(chal.Token)
case "tls-sni-02":
cert, name, err = client.TLSSNI02ChallengeCert(chal.Token)
default:
err = fmt.Errorf("acme/autocert: unknown challenge type %q", chal.Type)
}
if err != nil {
return err
}
m.putTokenCert(ctx, name, &cert)
defer func() {
// verification has ended at this point
// don't need token cert anymore
go m.deleteTokenCert(name)
}()
// ready to fulfill the challenge
if _, err := client.Accept(ctx, chal); err != nil {
return err
}
// wait for the CA to validate
_, err = client.WaitAuthorization(ctx, authz.URI)
return err
}
// putTokenCert stores the cert under the named key in both m.tokenCert map
// and m.Cache.
func (m *Manager) putTokenCert(ctx context.Context, name string, cert *tls.Certificate) {
m.tokenCertMu.Lock()
defer m.tokenCertMu.Unlock()
if m.tokenCert == nil {
m.tokenCert = make(map[string]*tls.Certificate)
// fulfill provisions a response to the challenge chal.
// The cleanup is non-nil only if provisioning succeeded.
func (m *Manager) fulfill(ctx context.Context, client *acme.Client, chal *acme.Challenge) (cleanup func(), err error) {
switch chal.Type {
case "tls-sni-01":
cert, name, err := client.TLSSNI01ChallengeCert(chal.Token)
if err != nil {
return nil, err
}
m.putCertToken(ctx, name, &cert)
return func() { go m.deleteCertToken(name) }, nil
case "tls-sni-02":
cert, name, err := client.TLSSNI02ChallengeCert(chal.Token)
if err != nil {
return nil, err
}
m.putCertToken(ctx, name, &cert)
return func() { go m.deleteCertToken(name) }, nil
case "http-01":
resp, err := client.HTTP01ChallengeResponse(chal.Token)
if err != nil {
return nil, err
}
p := client.HTTP01ChallengePath(chal.Token)
m.putHTTPToken(ctx, p, resp)
return func() { go m.deleteHTTPToken(p) }, nil
}
m.tokenCert[name] = cert
return nil, fmt.Errorf("acme/autocert: unknown challenge type %q", chal.Type)
}
func pickChallenge(typ string, chal []*acme.Challenge) *acme.Challenge {
for _, c := range chal {
if c.Type == typ {
return c
}
}
return nil
}
// putCertToken stores the cert under the named key in both m.certTokens map
// and m.Cache.
func (m *Manager) putCertToken(ctx context.Context, name string, cert *tls.Certificate) {
m.tokensMu.Lock()
defer m.tokensMu.Unlock()
if m.certTokens == nil {
m.certTokens = make(map[string]*tls.Certificate)
}
m.certTokens[name] = cert
m.cachePut(ctx, name, cert)
}
// deleteTokenCert removes the token certificate for the specified domain name
// from both m.tokenCert map and m.Cache.
func (m *Manager) deleteTokenCert(name string) {
m.tokenCertMu.Lock()
defer m.tokenCertMu.Unlock()
delete(m.tokenCert, name)
// deleteCertToken removes the token certificate for the specified domain name
// from both m.certTokens map and m.Cache.
func (m *Manager) deleteCertToken(name string) {
m.tokensMu.Lock()
defer m.tokensMu.Unlock()
delete(m.certTokens, name)
if m.Cache != nil {
m.Cache.Delete(context.Background(), name)
}
}
// httpToken retrieves an existing http-01 token value from an in-memory map
// or the optional cache.
func (m *Manager) httpToken(ctx context.Context, tokenPath string) ([]byte, error) {
m.tokensMu.RLock()
defer m.tokensMu.RUnlock()
if v, ok := m.httpTokens[tokenPath]; ok {
return v, nil
}
if m.Cache == nil {
return nil, fmt.Errorf("acme/autocert: no token at %q", tokenPath)
}
return m.Cache.Get(ctx, httpTokenCacheKey(tokenPath))
}
// putHTTPToken stores an http-01 token value using tokenPath as key
// in both in-memory map and the optional Cache.
//
// It ignores any error returned from Cache.Put.
func (m *Manager) putHTTPToken(ctx context.Context, tokenPath, val string) {
m.tokensMu.Lock()
defer m.tokensMu.Unlock()
if m.httpTokens == nil {
m.httpTokens = make(map[string][]byte)
}
b := []byte(val)
m.httpTokens[tokenPath] = b
if m.Cache != nil {
m.Cache.Put(ctx, httpTokenCacheKey(tokenPath), b)
}
}
// deleteHTTPToken removes an http-01 token value from both in-memory map
// and the optional Cache, ignoring any error returned from the latter.
//
// If m.Cache is non-nil, it blocks until Cache.Delete returns without a timeout.
func (m *Manager) deleteHTTPToken(tokenPath string) {
m.tokensMu.Lock()
defer m.tokensMu.Unlock()
delete(m.httpTokens, tokenPath)
if m.Cache != nil {
m.Cache.Delete(context.Background(), httpTokenCacheKey(tokenPath))
}
}
// httpTokenCacheKey returns a key at which an http-01 token value may be stored
// in the Manager's optional Cache.
func httpTokenCacheKey(tokenPath string) string {
return "http-01-" + path.Base(tokenPath)
}
// renew starts a cert renewal timer loop, one per domain.
//
// The loop is scheduled in two cases:

View file

@ -5,6 +5,8 @@
package acme
import (
"crypto"
"crypto/x509"
"errors"
"fmt"
"net/http"
@ -293,3 +295,35 @@ func (e *wireError) error(h http.Header) *Error {
Header: h,
}
}
// CertOption is an optional argument type for the TLSSNIxChallengeCert methods for
// customizing a temporary certificate for TLS-SNI challenges.
type CertOption interface {
privateCertOpt()
}
// WithKey creates an option holding a private/public key pair.
// The private part signs a certificate, and the public part represents the signee.
func WithKey(key crypto.Signer) CertOption {
return &certOptKey{key}
}
type certOptKey struct {
key crypto.Signer
}
func (*certOptKey) privateCertOpt() {}
// WithTemplate creates an option for specifying a certificate template.
// See x509.CreateCertificate for template usage details.
//
// In 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() {}

12
vendor/vendor.json vendored
View file

@ -1007,16 +1007,16 @@
"revisionTime": "2016-11-19T21:37:11Z"
},
{
"checksumSHA1": "Ag672Laei0E45NrvTO4LV9B3Jfc=",
"checksumSHA1": "CSMVjFF7FnylAUUKW1e/4r+VFXA=",
"path": "golang.org/x/crypto/acme",
"revision": "c7af5bf2638a1164f2eb5467c39c6cffbd13a02e",
"revisionTime": "2017-04-25T18:31:00Z"
"revision": "13931e22f9e72ea58bb73048bc752b48c6d4d4ac",
"revisionTime": "2018-01-11T11:10:38Z"
},
{
"checksumSHA1": "TrKJW+flz7JulXU3sqnBJjGzgQc=",
"checksumSHA1": "lBWiVnI+9tnYWuXnUiWljDy9dnc=",
"path": "golang.org/x/crypto/acme/autocert",
"revision": "c7af5bf2638a1164f2eb5467c39c6cffbd13a02e",
"revisionTime": "2017-04-25T18:31:00Z"
"revision": "13931e22f9e72ea58bb73048bc752b48c6d4d4ac",
"revisionTime": "2018-01-11T11:10:38Z"
},
{
"checksumSHA1": "MlEHIE/60sB86Lmf0MPTIXHzKzE=",