Adding ability to serve TLS directly from Mattermost server (#4119)

vendor/github.com/rsc/letsencrypt/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/rsc/letsencrypt/README

@@ -0,0 +1,152 @@
+package letsencrypt // import "rsc.io/letsencrypt"
+
+Package letsencrypt obtains TLS certificates from LetsEncrypt.org.
+
+LetsEncrypt.org is a service that issues free SSL/TLS certificates to
+servers that can prove control over the given domain's DNS records or the
+servers pointed at by those records.
+
+
+Quick Start
+
+A complete HTTP/HTTPS web server using TLS certificates from
+LetsEncrypt.org, redirecting all HTTP access to HTTPS, and maintaining TLS
+certificates in a file letsencrypt.cache across server restarts.
+
+    package main
+
+    import (
+    	"fmt"
+    	"log"
+    	"net/http"
+    	"rsc.io/letsencrypt"
+    )
+
+    func main() {
+    	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+    		fmt.Fprintf(w, "Hello, TLS!\n")
+    	})
+    	var m letsencrypt.Manager
+    	if err := m.CacheFile("letsencrypt.cache"); err != nil {
+    		log.Fatal(err)
+    	}
+    	log.Fatal(m.Serve())
+    }
+
+
+Overview
+
+The fundamental type in this package is the Manager, which manages obtaining
+and refreshing a collection of TLS certificates, typically for use by an
+HTTPS server. The example above shows the most basic use of a Manager. The
+use can be customized by calling additional methods of the Manager.
+
+
+Registration
+
+A Manager m registers anonymously with LetsEncrypt.org, including agreeing
+to the letsencrypt.org terms of service, the first time it needs to obtain a
+certificate. To register with a particular email address and with the option
+of a prompt for agreement with the terms of service, call m.Register.
+
+
+GetCertificate
+
+The Manager's GetCertificate method returns certificates from the Manager's
+cache, filling the cache by requesting certificates from LetsEncrypt.org. In
+this way, a server with a tls.Config.GetCertificate set to m.GetCertificate
+will demand load a certificate for any host name it serves. To force loading
+of certificates ahead of time, install m.GetCertificate as before but then
+call m.Cert for each host name.
+
+A Manager can only obtain a certificate for a given host name if it can
+prove control of that host name to LetsEncrypt.org. By default it proves
+control by answering an HTTPS-based challenge: when the LetsEncrypt.org
+servers connect to the named host on port 443 (HTTPS), the TLS SNI handshake
+must use m.GetCertificate to obtain a per-host certificate. The most common
+way to satisfy this requirement is for the host name to resolve to the IP
+address of a (single) computer running m.ServeHTTPS, or at least running a
+Go TLS server with tls.Config.GetCertificate set to m.GetCertificate.
+However, other configurations are possible. For example, a group of machines
+could use an implementation of tls.Config.GetCertificate that cached
+certificates but handled cache misses by making RPCs to a Manager m on an
+elected leader machine.
+
+In typical usage, then, the setting of tls.Config.GetCertificate to
+m.GetCertificate serves two purposes: it provides certificates to the TLS
+server for ordinary serving, and it also answers challenges to prove
+ownership of the domains in order to obtain those certificates.
+
+To force the loading of a certificate for a given host into the Manager's
+cache, use m.Cert.
+
+
+Persistent Storage
+
+If a server always starts with a zero Manager m, the server effectively
+fetches a new certificate for each of its host name from LetsEncrypt.org on
+each restart. This is unfortunate both because the server cannot start if
+LetsEncrypt.org is unavailable and because LetsEncrypt.org limits how often
+it will issue a certificate for a given host name (at time of writing, the
+limit is 5 per week for a given host name). To save server state proactively
+to a cache file and to reload the server state from that same file when
+creating a new manager, call m.CacheFile with the name of the file to use.
+
+For alternate storage uses, m.Marshal returns the current state of the
+Manager as an opaque string, m.Unmarshal sets the state of the Manager using
+a string previously returned by m.Marshal (usually a different m), and
+m.Watch returns a channel that receives notifications about state changes.
+
+
+Limits
+
+To avoid hitting basic rate limits on LetsEncrypt.org, a given Manager
+limits all its interactions to at most one request every minute, with an
+initial allowed burst of 20 requests.
+
+By default, if GetCertificate is asked for a certificate it does not have,
+it will in turn ask LetsEncrypt.org for that certificate. This opens a
+potential attack where attackers connect to a server by IP address and
+pretend to be asking for an incorrect host name. Then GetCertificate will
+attempt to obtain a certificate for that host, incorrectly, eventually
+hitting LetsEncrypt.org's rate limit for certificate requests and making it
+impossible to obtain actual certificates. Because servers hold certificates
+for months at a time, however, an attack would need to be sustained over a
+time period of at least a month in order to cause real problems.
+
+To mitigate this kind of attack, a given Manager limits itself to an average
+of one certificate request for a new host every three hours, with an initial
+allowed burst of up to 20 requests. Long-running servers will therefore stay
+within the LetsEncrypt.org limit of 300 failed requests per month.
+Certificate refreshes are not subject to this limit.
+
+To eliminate the attack entirely, call m.SetHosts to enumerate the exact set
+of hosts that are allowed in certificate requests.
+
+
+Web Servers
+
+The basic requirement for use of a Manager is that there be an HTTPS server
+running on port 443 and calling m.GetCertificate to obtain TLS certificates.
+Using standard primitives, the way to do this is:
+
+    srv := &http.Server{
+    	Addr: ":https",
+    	TLSConfig: &tls.Config{
+    		GetCertificate: m.GetCertificate,
+    	},
+    }
+    srv.ListenAndServeTLS("", "")
+
+However, this pattern of serving HTTPS with demand-loaded TLS certificates
+comes up enough to wrap into a single method m.ServeHTTPS.
+
+Similarly, many HTTPS servers prefer to redirect HTTP clients to the HTTPS
+URLs. That functionality is provided by RedirectHTTP.
+
+The combination of serving HTTPS with demand-loaded TLS certificates and
+serving HTTPS redirects to HTTP clients is provided by m.Serve, as used in
+the original example above.
+
+func RedirectHTTP(w http.ResponseWriter, r *http.Request)
+type Manager struct { ... }

vendor/github.com/rsc/letsencrypt/lets.go

@@ -0,0 +1,757 @@
+// Copyright 2016 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package letsencrypt obtains TLS certificates from LetsEncrypt.org.
+//
+// LetsEncrypt.org is a service that issues free SSL/TLS certificates to servers
+// that can prove control over the given domain's DNS records or
+// the servers pointed at by those records.
+//
+// Quick Start
+//
+// A complete HTTP/HTTPS web server using TLS certificates from LetsEncrypt.org,
+// redirecting all HTTP access to HTTPS, and maintaining TLS certificates in a file
+// letsencrypt.cache across server restarts.
+//
+//	package main
+//
+//	import (
+//		"fmt"
+//		"log"
+//		"net/http"
+//		"rsc.io/letsencrypt"
+//	)
+//
+//	func main() {
+//		http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+//			fmt.Fprintf(w, "Hello, TLS!\n")
+//		})
+//		var m letsencrypt.Manager
+//		if err := m.CacheFile("letsencrypt.cache"); err != nil {
+//			log.Fatal(err)
+//		}
+//		log.Fatal(m.Serve())
+//	}
+//
+// Overview
+//
+// The fundamental type in this package is the Manager, which
+// manages obtaining and refreshing a collection of TLS certificates,
+// typically for use by an HTTPS server.
+// The example above shows the most basic use of a Manager.
+// The use can be customized by calling additional methods of the Manager.
+//
+// Registration
+//
+// A Manager m registers anonymously with LetsEncrypt.org, including agreeing to
+// the letsencrypt.org terms of service, the first time it needs to obtain a certificate.
+// To register with a particular email address and with the option of a
+// prompt for agreement with the terms of service, call m.Register.
+//
+// GetCertificate
+//
+// The Manager's GetCertificate method returns certificates
+// from the Manager's cache, filling the cache by requesting certificates
+// from LetsEncrypt.org. In this way, a server with a tls.Config.GetCertificate
+// set to m.GetCertificate will demand load a certificate for any host name
+// it serves. To force loading of certificates ahead of time, install m.GetCertificate
+// as before but then call m.Cert for each host name.
+//
+// A Manager can only obtain a certificate for a given host name if it can prove
+// control of that host name to LetsEncrypt.org. By default it proves control by
+// answering an HTTPS-based challenge: when
+// the LetsEncrypt.org servers connect to the named host on port 443 (HTTPS),
+// the TLS SNI handshake must use m.GetCertificate to obtain a per-host certificate.
+// The most common way to satisfy this requirement is for the host name to
+// resolve to the IP address of a (single) computer running m.ServeHTTPS,
+// or at least running a Go TLS server with tls.Config.GetCertificate set to m.GetCertificate.
+// However, other configurations are possible. For example, a group of machines
+// could use an implementation of tls.Config.GetCertificate that cached
+// certificates but handled cache misses by making RPCs to a Manager m
+// on an elected leader machine.
+//
+// In typical usage, then, the setting of tls.Config.GetCertificate to m.GetCertificate
+// serves two purposes: it provides certificates to the TLS server for ordinary serving,
+// and it also answers challenges to prove ownership of the domains in order to
+// obtain those certificates.
+//
+// To force the loading of a certificate for a given host into the Manager's cache,
+// use m.Cert.
+//
+// Persistent Storage
+//
+// If a server always starts with a zero Manager m, the server effectively fetches
+// a new certificate for each of its host name from LetsEncrypt.org on each restart.
+// This is unfortunate both because the server cannot start if LetsEncrypt.org is
+// unavailable and because LetsEncrypt.org limits how often it will issue a certificate
+// for a given host name (at time of writing, the limit is 5 per week for a given host name).
+// To save server state proactively to a cache file and to reload the server state from
+// that same file when creating a new manager, call m.CacheFile with the name of
+// the file to use.
+//
+// For alternate storage uses, m.Marshal returns the current state of the Manager
+// as an opaque string, m.Unmarshal sets the state of the Manager using a string
+// previously returned by m.Marshal (usually a different m), and m.Watch returns
+// a channel that receives notifications about state changes.
+//
+// Limits
+//
+// To avoid hitting basic rate limits on LetsEncrypt.org, a given Manager limits all its
+// interactions to at most one request every minute, with an initial allowed burst of
+// 20 requests.
+//
+// By default, if GetCertificate is asked for a certificate it does not have, it will in turn
+// ask LetsEncrypt.org for that certificate. This opens a potential attack where attackers
+// connect to a server by IP address and pretend to be asking for an incorrect host name.
+// Then GetCertificate will attempt to obtain a certificate for that host, incorrectly,
+// eventually hitting LetsEncrypt.org's rate limit for certificate requests and making it
+// impossible to obtain actual certificates. Because servers hold certificates for months
+// at a time, however, an attack would need to be sustained over a time period
+// of at least a month in order to cause real problems.
+//
+// To mitigate this kind of attack, a given Manager limits
+// itself to an average of one certificate request for a new host every three hours,
+// with an initial allowed burst of up to 20 requests.
+// Long-running servers will therefore stay
+// within the LetsEncrypt.org limit of 300 failed requests per month.
+// Certificate refreshes are not subject to this limit.
+//
+// To eliminate the attack entirely, call m.SetHosts to enumerate the exact set
+// of hosts that are allowed in certificate requests.
+//
+// Web Servers
+//
+// The basic requirement for use of a Manager is that there be an HTTPS server
+// running on port 443 and calling m.GetCertificate to obtain TLS certificates.
+// Using standard primitives, the way to do this is:
+//
+//	srv := &http.Server{
+//		Addr: ":https",
+//		TLSConfig: &tls.Config{
+//			GetCertificate: m.GetCertificate,
+//		},
+//	}
+//	srv.ListenAndServeTLS("", "")
+//
+// However, this pattern of serving HTTPS with demand-loaded TLS certificates
+// comes up enough to wrap into a single method m.ServeHTTPS.
+//
+// Similarly, many HTTPS servers prefer to redirect HTTP clients to the HTTPS URLs.
+// That functionality is provided by RedirectHTTP.
+//
+// The combination of serving HTTPS with demand-loaded TLS certificates and
+// serving HTTPS redirects to HTTP clients is provided by m.Serve, as used in
+// the original example above.
+//
+package letsencrypt
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"encoding/pem"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+	"golang.org/x/time/rate"
+
+	"github.com/xenolf/lego/acme"
+)
+
+const letsEncryptURL = "https://acme-v01.api.letsencrypt.org/directory"
+const debug = false
+
+// A Manager m takes care of obtaining and refreshing a collection of TLS certificates
+// obtained by LetsEncrypt.org.
+//  The zero Manager is not yet registered with LetsEncrypt.org and has no TLS certificates
+// but is nonetheless ready for use.
+// See the package comment for an overview of how to use a Manager.
+type Manager struct {
+	mu           sync.Mutex
+	state        state
+	rateLimit    *rate.Limiter
+	newHostLimit *rate.Limiter
+	certCache    map[string]*cacheEntry
+	certTokens   map[string]*tls.Certificate
+	watchChan    chan struct{}
+}
+
+// Serve runs an HTTP/HTTPS web server using TLS certificates obtained by the manager.
+// The HTTP server redirects all requests to the HTTPS server.
+// The HTTPS server obtains TLS certificates as needed and responds to requests
+// by invoking http.DefaultServeMux.
+//
+// Serve does not return unitil the HTTPS server fails to start or else stops.
+// Either way, Serve can only return a non-nil error, never nil.
+func (m *Manager) Serve() error {
+	l, err := net.Listen("tcp", ":http")
+	if err != nil {
+		return err
+	}
+	defer l.Close()
+	go http.Serve(l, http.HandlerFunc(RedirectHTTP))
+
+	return m.ServeHTTPS()
+}
+
+// ServeHTTPS runs an HTTPS web server using TLS certificates obtained by the manager.
+// The HTTPS server obtains TLS certificates as needed and responds to requests
+// by invoking http.DefaultServeMux.
+// ServeHTTPS does not return unitil the HTTPS server fails to start or else stops.
+// Either way, ServeHTTPS can only return a non-nil error, never nil.
+func (m *Manager) ServeHTTPS() error {
+	srv := &http.Server{
+		Addr: ":https",
+		TLSConfig: &tls.Config{
+			GetCertificate: m.GetCertificate,
+		},
+	}
+	return srv.ListenAndServeTLS("", "")
+}
+
+// RedirectHTTP is an HTTP handler (suitable for use with http.HandleFunc)
+// that responds to all requests by redirecting to the same URL served over HTTPS.
+// It should only be invoked for requests received over HTTP.
+func RedirectHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.TLS != nil || r.Host == "" {
+		http.Error(w, "not found", 404)
+	}
+
+	u := r.URL
+	u.Host = r.Host
+	u.Scheme = "https"
+	http.Redirect(w, r, u.String(), 302)
+}
+
+// state is the serializable state for the Manager.
+// It also implements acme.User.
+type state struct {
+	Email string
+	Reg   *acme.RegistrationResource
+	Key   string
+	key   *ecdsa.PrivateKey
+	Hosts []string
+	Certs map[string]stateCert
+}
+
+func (s *state) GetEmail() string                            { return s.Email }
+func (s *state) GetRegistration() *acme.RegistrationResource { return s.Reg }
+func (s *state) GetPrivateKey() crypto.PrivateKey            { return s.key }
+
+type stateCert struct {
+	Cert string
+	Key  string
+}
+
+func (cert stateCert) toTLS() (*tls.Certificate, error) {
+	c, err := tls.X509KeyPair([]byte(cert.Cert), []byte(cert.Key))
+	if err != nil {
+		return nil, err
+	}
+	return &c, err
+}
+
+type cacheEntry struct {
+	host string
+	m    *Manager
+
+	mu         sync.Mutex
+	cert       *tls.Certificate
+	timeout    time.Time
+	refreshing bool
+	err        error
+}
+
+func (m *Manager) init() {
+	m.mu.Lock()
+	if m.certCache == nil {
+		m.rateLimit = rate.NewLimiter(rate.Every(1*time.Minute), 20)
+		m.newHostLimit = rate.NewLimiter(rate.Every(3*time.Hour), 20)
+		m.certCache = map[string]*cacheEntry{}
+		m.certTokens = map[string]*tls.Certificate{}
+		m.watchChan = make(chan struct{}, 1)
+		m.watchChan <- struct{}{}
+	}
+	m.mu.Unlock()
+}
+
+// Watch returns the manager's watch channel,
+// which delivers a notification after every time the
+// manager's state (as exposed by Marshal and Unmarshal) changes.
+// All calls to Watch return the same watch channel.
+//
+// The watch channel includes notifications about changes
+// before the first call to Watch, so that in the pattern below,
+// the range loop executes once immediately, saving
+// the result of setup (along with any background updates that
+// may have raced in quickly).
+//
+//	m := new(letsencrypt.Manager)
+//	setup(m)
+//	go backgroundUpdates(m)
+//	for range m.Watch() {
+//		save(m.Marshal())
+//	}
+//
+func (m *Manager) Watch() <-chan struct{} {
+	m.init()
+	m.updated()
+	return m.watchChan
+}
+
+func (m *Manager) updated() {
+	select {
+	case m.watchChan <- struct{}{}:
+	default:
+	}
+}
+
+func (m *Manager) CacheFile(name string) error {
+	f, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE, 0600)
+	if err != nil {
+		return err
+	}
+	f.Close()
+	data, err := ioutil.ReadFile(name)
+	if err != nil {
+		return err
+	}
+	if len(data) > 0 {
+		if err := m.Unmarshal(string(data)); err != nil {
+			return err
+		}
+	}
+	go func() {
+		for range m.Watch() {
+			err := ioutil.WriteFile(name, []byte(m.Marshal()), 0600)
+			if err != nil {
+				log.Printf("writing letsencrypt cache: %v", err)
+			}
+		}
+	}()
+	return nil
+}
+
+// Registered reports whether the manager has registered with letsencrypt.org yet.
+func (m *Manager) Registered() bool {
+	m.init()
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return m.registered()
+}
+
+func (m *Manager) registered() bool {
+	return m.state.Reg != nil && m.state.Reg.Body.Agreement != ""
+}
+
+// Register registers the manager with letsencrypt.org, using the given email address.
+// Registration may require agreeing to the letsencrypt.org terms of service.
+// If so, Register calls prompt(url) where url is the URL of the terms of service.
+// Prompt should report whether the caller agrees to the terms.
+// A nil prompt func is taken to mean that the user always agrees.
+// The email address is sent to LetsEncrypt.org but otherwise unchecked;
+// it can be omitted by passing the empty string.
+//
+// Calling Register is only required to make sure registration uses a
+// particular email address or to insert an explicit prompt into the
+// registration sequence. If the manager is not registered, it will
+// automatically register with no email address and automatic
+// agreement to the terms of service at the first call to Cert or GetCertificate.
+func (m *Manager) Register(email string, prompt func(string) bool) error {
+	m.init()
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	return m.register(email, prompt)
+}
+
+func (m *Manager) register(email string, prompt func(string) bool) error {
+	if m.registered() {
+		return fmt.Errorf("already registered")
+	}
+	m.state.Email = email
+	if m.state.key == nil {
+		key, err := newKey()
+		if err != nil {
+			return fmt.Errorf("generating key: %v", err)
+		}
+		Key, err := marshalKey(key)
+		if err != nil {
+			return fmt.Errorf("generating key: %v", err)
+		}
+		m.state.key = key
+		m.state.Key = string(Key)
+	}
+
+	c, err := acme.NewClient(letsEncryptURL, &m.state, acme.EC256)
+	if err != nil {
+		return fmt.Errorf("create client: %v", err)
+	}
+	reg, err := c.Register()
+	if err != nil {
+		return fmt.Errorf("register: %v", err)
+	}
+
+	m.state.Reg = reg
+	if reg.Body.Agreement == "" {
+		if prompt != nil && !prompt(reg.TosURL) {
+			return fmt.Errorf("did not agree to TOS")
+		}
+		if err := c.AgreeToTOS(); err != nil {
+			return fmt.Errorf("agreeing to TOS: %v", err)
+		}
+	}
+
+	m.updated()
+
+	return nil
+}
+
+// Marshal returns an encoding of the manager's state,
+// suitable for writing to disk and reloading by calling Unmarshal.
+// The state includes registration status, the configured host list
+// from SetHosts, and all known certificates, including their private
+// cryptographic keys.
+// Consequently, the state should be kept private.
+func (m *Manager) Marshal() string {
+	m.init()
+	m.mu.Lock()
+	js, err := json.MarshalIndent(&m.state, "", "\t")
+	m.mu.Unlock()
+	if err != nil {
+		panic("unexpected json.Marshal failure")
+	}
+	return string(js)
+}
+
+// Unmarshal restores the state encoded by a previous call to Marshal
+// (perhaps on a different Manager in a different program).
+func (m *Manager) Unmarshal(enc string) error {
+	m.init()
+	var st state
+	if err := json.Unmarshal([]byte(enc), &st); err != nil {
+		return err
+	}
+	if st.Key != "" {
+		key, err := unmarshalKey(st.Key)
+		if err != nil {
+			return err
+		}
+		st.key = key
+	}
+	m.mu.Lock()
+	m.state = st
+	m.mu.Unlock()
+	for host, cert := range m.state.Certs {
+		c, err := cert.toTLS()
+		if err != nil {
+			log.Printf("letsencrypt: ignoring entry for %s: %v", host, err)
+			continue
+		}
+		m.certCache[host] = &cacheEntry{host: host, m: m, cert: c}
+	}
+	m.updated()
+	return nil
+}
+
+// SetHosts sets the manager's list of known host names.
+// If the list is non-nil, the manager will only ever attempt to acquire
+// certificates for host names on the list.
+// If the list is nil, the manager does not restrict the hosts it will
+// ask for certificates for.
+func (m *Manager) SetHosts(hosts []string) {
+	m.init()
+	m.mu.Lock()
+	m.state.Hosts = append(m.state.Hosts[:0], hosts...)
+	m.mu.Unlock()
+	m.updated()
+}
+
+// GetCertificate can be placed a tls.Config's GetCertificate field to make
+// the TLS server use Let's Encrypt certificates.
+// Each time a client connects to the TLS server expecting a new host name,
+// the TLS server's call to GetCertificate will trigger an exchange with the
+// Let's Encrypt servers to obtain that certificate, subject to the manager rate limits.
+//
+// As noted in the Manager's documentation comment,
+// to obtain a certificate for a given host name, that name
+// must resolve to a computer running a TLS server on port 443
+// that obtains TLS SNI certificates by calling m.GetCertificate.
+// In the standard usage, then, installing m.GetCertificate in the tls.Config
+// both automatically provisions the TLS certificates needed for
+// ordinary HTTPS service and answers the challenges from LetsEncrypt.org.
+func (m *Manager) GetCertificate(clientHello *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	m.init()
+
+	host := clientHello.ServerName
+
+	if debug {
+		log.Printf("GetCertificate %s", host)
+	}
+
+	if strings.HasSuffix(host, ".acme.invalid") {
+		m.mu.Lock()
+		cert := m.certTokens[host]
+		m.mu.Unlock()
+		if cert == nil {
+			return nil, fmt.Errorf("unknown host")
+		}
+		return cert, nil
+	}
+
+	return m.Cert(host)
+}
+
+// Cert returns the certificate for the given host name, obtaining a new one if necessary.
+//
+// As noted in the documentation for Manager and for the GetCertificate method,
+// obtaining a certificate requires that m.GetCertificate be associated with host.
+// In most servers, simply starting a TLS server with a configuration referring
+// to m.GetCertificate is sufficient, and Cert need not be called.
+//
+// The main use of Cert is to force the manager to obtain a certificate
+// for a particular host name ahead of time.
+func (m *Manager) Cert(host string) (*tls.Certificate, error) {
+	host = strings.ToLower(host)
+	if debug {
+		log.Printf("Cert %s", host)
+	}
+
+	m.init()
+	m.mu.Lock()
+	if !m.registered() {
+		m.register("", nil)
+	}
+
+	ok := false
+	if m.state.Hosts == nil {
+		ok = true
+	} else {
+		for _, h := range m.state.Hosts {
+			if host == h {
+				ok = true
+				break
+			}
+		}
+	}
+	if !ok {
+		m.mu.Unlock()
+		return nil, fmt.Errorf("unknown host")
+	}
+
+	// Otherwise look in our cert cache.
+	entry, ok := m.certCache[host]
+	if !ok {
+		r := m.rateLimit.Reserve()
+		ok := r.OK()
+		if ok {
+			ok = m.newHostLimit.Allow()
+			if !ok {
+				r.Cancel()
+			}
+		}
+		if !ok {
+			m.mu.Unlock()
+			return nil, fmt.Errorf("rate limited")
+		}
+		entry = &cacheEntry{host: host, m: m}
+		m.certCache[host] = entry
+	}
+	m.mu.Unlock()
+
+	entry.mu.Lock()
+	defer entry.mu.Unlock()
+	entry.init()
+	if entry.err != nil {
+		return nil, entry.err
+	}
+	return entry.cert, nil
+}
+
+func (e *cacheEntry) init() {
+	if e.err != nil && time.Now().Before(e.timeout) {
+		return
+	}
+	if e.cert != nil {
+		if e.timeout.IsZero() {
+			t, err := certRefreshTime(e.cert)
+			if err != nil {
+				e.err = err
+				e.timeout = time.Now().Add(1 * time.Minute)
+				e.cert = nil
+				return
+			}
+			e.timeout = t
+		}
+		if time.Now().After(e.timeout) && !e.refreshing {
+			e.refreshing = true
+			go e.refresh()
+		}
+		return
+	}
+
+	cert, refreshTime, err := e.m.verify(e.host)
+	e.m.mu.Lock()
+	e.m.certCache[e.host] = e
+	e.m.mu.Unlock()
+	e.install(cert, refreshTime, err)
+}
+
+func (e *cacheEntry) install(cert *tls.Certificate, refreshTime time.Time, err error) {
+	e.cert = nil
+	e.timeout = time.Time{}
+	e.err = nil
+
+	if err != nil {
+		e.err = err
+		e.timeout = time.Now().Add(1 * time.Minute)
+		return
+	}
+
+	e.cert = cert
+	e.timeout = refreshTime
+}
+
+func (e *cacheEntry) refresh() {
+	e.m.rateLimit.Wait(context.Background())
+	cert, refreshTime, err := e.m.verify(e.host)
+
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	e.refreshing = false
+	if err == nil {
+		e.install(cert, refreshTime, nil)
+	}
+}
+
+func (m *Manager) verify(host string) (cert *tls.Certificate, refreshTime time.Time, err error) {
+	c, err := acme.NewClient(letsEncryptURL, &m.state, acme.EC256)
+	if err != nil {
+		return
+	}
+	if err = c.SetChallengeProvider(acme.TLSSNI01, tlsProvider{m}); err != nil {
+		return
+	}
+	c.SetChallengeProvider(acme.TLSSNI01, tlsProvider{m})
+	c.ExcludeChallenges([]acme.Challenge{acme.HTTP01})
+	acmeCert, errmap := c.ObtainCertificate([]string{host}, true, nil)
+	if len(errmap) > 0 {
+		if debug {
+			log.Printf("ObtainCertificate %v => %v", host, errmap)
+		}
+		err = fmt.Errorf("%v", errmap)
+		return
+	}
+	entryCert := stateCert{
+		Cert: string(acmeCert.Certificate),
+		Key:  string(acmeCert.PrivateKey),
+	}
+	cert, err = entryCert.toTLS()
+	if err != nil {
+		if debug {
+			log.Printf("ObtainCertificate %v toTLS failure: %v", host, err)
+		}
+		err = err
+		return
+	}
+	if refreshTime, err = certRefreshTime(cert); err != nil {
+		return
+	}
+
+	m.mu.Lock()
+	if m.state.Certs == nil {
+		m.state.Certs = make(map[string]stateCert)
+	}
+	m.state.Certs[host] = entryCert
+	m.mu.Unlock()
+	m.updated()
+
+	return cert, refreshTime, nil
+}
+
+func certRefreshTime(cert *tls.Certificate) (time.Time, error) {
+	xc, err := x509.ParseCertificate(cert.Certificate[0])
+	if err != nil {
+		if debug {
+			log.Printf("ObtainCertificate to X.509 failure: %v", err)
+		}
+		return time.Time{}, err
+	}
+	t := xc.NotBefore.Add(xc.NotAfter.Sub(xc.NotBefore) / 2)
+	monthEarly := xc.NotAfter.Add(-30 * 24 * time.Hour)
+	if t.Before(monthEarly) {
+		t = monthEarly
+	}
+	return t, nil
+}
+
+// tlsProvider implements acme.ChallengeProvider for TLS handshake challenges.
+type tlsProvider struct {
+	m *Manager
+}
+
+func (p tlsProvider) Present(domain, token, keyAuth string) error {
+	cert, dom, err := acme.TLSSNI01ChallengeCertDomain(keyAuth)
+	if err != nil {
+		return err
+	}
+
+	p.m.mu.Lock()
+	p.m.certTokens[dom] = &cert
+	p.m.mu.Unlock()
+
+	return nil
+}
+
+func (p tlsProvider) CleanUp(domain, token, keyAuth string) error {
+	_, dom, err := acme.TLSSNI01ChallengeCertDomain(keyAuth)
+	if err != nil {
+		return err
+	}
+
+	p.m.mu.Lock()
+	delete(p.m.certTokens, dom)
+	p.m.mu.Unlock()
+
+	return nil
+}
+
+func marshalKey(key *ecdsa.PrivateKey) ([]byte, error) {
+	data, err := x509.MarshalECPrivateKey(key)
+	if err != nil {
+		return nil, err
+	}
+	return pem.EncodeToMemory(&pem.Block{Type: "EC PRIVATE KEY", Bytes: data}), nil
+}
+
+func unmarshalKey(text string) (*ecdsa.PrivateKey, error) {
+	b, _ := pem.Decode([]byte(text))
+	if b == nil {
+		return nil, fmt.Errorf("unmarshalKey: missing key")
+	}
+	if b.Type != "EC PRIVATE KEY" {
+		return nil, fmt.Errorf("unmarshalKey: found %q, not %q", b.Type, "EC PRIVATE KEY")
+	}
+	k, err := x509.ParseECPrivateKey(b.Bytes)
+	if err != nil {
+		return nil, fmt.Errorf("unmarshalKey: %v", err)
+	}
+	return k, nil
+}
+
+func newKey() (*ecdsa.PrivateKey, error) {
+	return ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/LICENSE

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

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/challenges.go

@@ -0,0 +1,16 @@
+package acme
+
+// Challenge is a string that identifies a particular type and version of ACME challenge.
+type Challenge string
+
+const (
+	// HTTP01 is the "http-01" ACME challenge https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md#http
+	// Note: HTTP01ChallengePath returns the URL path to fulfill this challenge
+	HTTP01 = Challenge("http-01")
+	// TLSSNI01 is the "tls-sni-01" ACME challenge https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md#tls-with-server-name-indication-tls-sni
+	// Note: TLSSNI01ChallengeCert returns a certificate to fulfill this challenge
+	TLSSNI01 = Challenge("tls-sni-01")
+	// DNS01 is the "dns-01" ACME challenge https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md#dns
+	// Note: DNS01Record returns a DNS record which will fulfill this challenge
+	DNS01 = Challenge("dns-01")
+)

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/client.go

@@ -0,0 +1,638 @@
+// Package acme implements the ACME protocol for Let's Encrypt and other conforming providers.
+package acme
+
+import (
+	"crypto"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var (
+	// Logger is an optional custom logger.
+	Logger *log.Logger
+)
+
+// logf writes a log entry. It uses Logger if not
+// nil, otherwise it uses the default log.Logger.
+func logf(format string, args ...interface{}) {
+	if Logger != nil {
+		Logger.Printf(format, args...)
+	} else {
+		log.Printf(format, args...)
+	}
+}
+
+// User interface is to be implemented by users of this library.
+// It is used by the client type to get user specific information.
+type User interface {
+	GetEmail() string
+	GetRegistration() *RegistrationResource
+	GetPrivateKey() crypto.PrivateKey
+}
+
+// Interface for all challenge solvers to implement.
+type solver interface {
+	Solve(challenge challenge, domain string) error
+}
+
+type validateFunc func(j *jws, domain, uri string, chlng challenge) error
+
+// Client is the user-friendy way to ACME
+type Client struct {
+	directory  directory
+	user       User
+	jws        *jws
+	keyType    KeyType
+	issuerCert []byte
+	solvers    map[Challenge]solver
+}
+
+// NewClient creates a new ACME client on behalf of the user. The client will depend on
+// the ACME directory located at caDirURL for the rest of its actions. It will
+// generate private keys for certificates of size keyBits.
+func NewClient(caDirURL string, user User, keyType KeyType) (*Client, error) {
+	privKey := user.GetPrivateKey()
+	if privKey == nil {
+		return nil, errors.New("private key was nil")
+	}
+
+	var dir directory
+	if _, err := getJSON(caDirURL, &dir); err != nil {
+		return nil, fmt.Errorf("get directory at '%s': %v", caDirURL, err)
+	}
+
+	if dir.NewRegURL == "" {
+		return nil, errors.New("directory missing new registration URL")
+	}
+	if dir.NewAuthzURL == "" {
+		return nil, errors.New("directory missing new authz URL")
+	}
+	if dir.NewCertURL == "" {
+		return nil, errors.New("directory missing new certificate URL")
+	}
+	if dir.RevokeCertURL == "" {
+		return nil, errors.New("directory missing revoke certificate URL")
+	}
+
+	jws := &jws{privKey: privKey, directoryURL: caDirURL}
+
+	// REVIEW: best possibility?
+	// Add all available solvers with the right index as per ACME
+	// spec to this map. Otherwise they won`t be found.
+	solvers := make(map[Challenge]solver)
+	solvers[HTTP01] = &httpChallenge{jws: jws, validate: validate, provider: &HTTPProviderServer{}}
+	solvers[TLSSNI01] = &tlsSNIChallenge{jws: jws, validate: validate, provider: &TLSProviderServer{}}
+
+	return &Client{directory: dir, user: user, jws: jws, keyType: keyType, solvers: solvers}, nil
+}
+
+// SetChallengeProvider specifies a custom provider that will make the solution available
+func (c *Client) SetChallengeProvider(challenge Challenge, p ChallengeProvider) error {
+	switch challenge {
+	case HTTP01:
+		c.solvers[challenge] = &httpChallenge{jws: c.jws, validate: validate, provider: p}
+	case TLSSNI01:
+		c.solvers[challenge] = &tlsSNIChallenge{jws: c.jws, validate: validate, provider: p}
+	default:
+		return fmt.Errorf("Unknown challenge %v", challenge)
+	}
+	return nil
+}
+
+// SetHTTPAddress specifies a custom interface:port to be used for HTTP based challenges.
+// If this option is not used, the default port 80 and all interfaces will be used.
+// To only specify a port and no interface use the ":port" notation.
+func (c *Client) SetHTTPAddress(iface string) error {
+	host, port, err := net.SplitHostPort(iface)
+	if err != nil {
+		return err
+	}
+
+	if chlng, ok := c.solvers[HTTP01]; ok {
+		chlng.(*httpChallenge).provider = NewHTTPProviderServer(host, port)
+	}
+
+	return nil
+}
+
+// SetTLSAddress specifies a custom interface:port to be used for TLS based challenges.
+// If this option is not used, the default port 443 and all interfaces will be used.
+// To only specify a port and no interface use the ":port" notation.
+func (c *Client) SetTLSAddress(iface string) error {
+	host, port, err := net.SplitHostPort(iface)
+	if err != nil {
+		return err
+	}
+
+	if chlng, ok := c.solvers[TLSSNI01]; ok {
+		chlng.(*tlsSNIChallenge).provider = NewTLSProviderServer(host, port)
+	}
+	return nil
+}
+
+// ExcludeChallenges explicitly removes challenges from the pool for solving.
+func (c *Client) ExcludeChallenges(challenges []Challenge) {
+	// Loop through all challenges and delete the requested one if found.
+	for _, challenge := range challenges {
+		delete(c.solvers, challenge)
+	}
+}
+
+// Register the current account to the ACME server.
+func (c *Client) Register() (*RegistrationResource, error) {
+	if c == nil || c.user == nil {
+		return nil, errors.New("acme: cannot register a nil client or user")
+	}
+	logf("[INFO] acme: Registering account for %s", c.user.GetEmail())
+
+	regMsg := registrationMessage{
+		Resource: "new-reg",
+	}
+	if c.user.GetEmail() != "" {
+		regMsg.Contact = []string{"mailto:" + c.user.GetEmail()}
+	} else {
+		regMsg.Contact = []string{}
+	}
+
+	var serverReg Registration
+	hdr, err := postJSON(c.jws, c.directory.NewRegURL, regMsg, &serverReg)
+	if err != nil {
+		return nil, err
+	}
+
+	reg := &RegistrationResource{Body: serverReg}
+
+	links := parseLinks(hdr["Link"])
+	reg.URI = hdr.Get("Location")
+	if links["terms-of-service"] != "" {
+		reg.TosURL = links["terms-of-service"]
+	}
+
+	if links["next"] != "" {
+		reg.NewAuthzURL = links["next"]
+	} else {
+		return nil, errors.New("acme: The server did not return 'next' link to proceed")
+	}
+
+	return reg, nil
+}
+
+// AgreeToTOS updates the Client registration and sends the agreement to
+// the server.
+func (c *Client) AgreeToTOS() error {
+	reg := c.user.GetRegistration()
+
+	reg.Body.Agreement = c.user.GetRegistration().TosURL
+	reg.Body.Resource = "reg"
+	_, err := postJSON(c.jws, c.user.GetRegistration().URI, c.user.GetRegistration().Body, nil)
+	return err
+}
+
+// ObtainCertificate tries to obtain a single certificate using all domains passed into it.
+// The first domain in domains is used for the CommonName field of the certificate, all other
+// domains are added using the Subject Alternate Names extension. A new private key is generated
+// for every invocation of this function. If you do not want that you can supply your own private key
+// in the privKey parameter. If this parameter is non-nil it will be used instead of generating a new one.
+// If bundle is true, the []byte contains both the issuer certificate and
+// your issued certificate as a bundle.
+// This function will never return a partial certificate. If one domain in the list fails,
+// the whole certificate will fail.
+func (c *Client) ObtainCertificate(domains []string, bundle bool, privKey crypto.PrivateKey) (CertificateResource, map[string]error) {
+	if bundle {
+		logf("[INFO][%s] acme: Obtaining bundled SAN certificate", strings.Join(domains, ", "))
+	} else {
+		logf("[INFO][%s] acme: Obtaining SAN certificate", strings.Join(domains, ", "))
+	}
+
+	challenges, failures := c.getChallenges(domains)
+	// If any challenge fails - return. Do not generate partial SAN certificates.
+	if len(failures) > 0 {
+		return CertificateResource{}, failures
+	}
+
+	errs := c.solveChallenges(challenges)
+	// If any challenge fails - return. Do not generate partial SAN certificates.
+	if len(errs) > 0 {
+		return CertificateResource{}, errs
+	}
+
+	logf("[INFO][%s] acme: Validations succeeded; requesting certificates", strings.Join(domains, ", "))
+
+	cert, err := c.requestCertificate(challenges, bundle, privKey)
+	if err != nil {
+		for _, chln := range challenges {
+			failures[chln.Domain] = err
+		}
+	}
+
+	return cert, failures
+}
+
+// RevokeCertificate takes a PEM encoded certificate or bundle and tries to revoke it at the CA.
+func (c *Client) RevokeCertificate(certificate []byte) error {
+	certificates, err := parsePEMBundle(certificate)
+	if err != nil {
+		return err
+	}
+
+	x509Cert := certificates[0]
+	if x509Cert.IsCA {
+		return fmt.Errorf("Certificate bundle starts with a CA certificate")
+	}
+
+	encodedCert := base64.URLEncoding.EncodeToString(x509Cert.Raw)
+
+	_, err = postJSON(c.jws, c.directory.RevokeCertURL, revokeCertMessage{Resource: "revoke-cert", Certificate: encodedCert}, nil)
+	return err
+}
+
+// RenewCertificate takes a CertificateResource and tries to renew the certificate.
+// If the renewal process succeeds, the new certificate will ge returned in a new CertResource.
+// Please be aware that this function will return a new certificate in ANY case that is not an error.
+// If the server does not provide us with a new cert on a GET request to the CertURL
+// this function will start a new-cert flow where a new certificate gets generated.
+// If bundle is true, the []byte contains both the issuer certificate and
+// your issued certificate as a bundle.
+// For private key reuse the PrivateKey property of the passed in CertificateResource should be non-nil.
+func (c *Client) RenewCertificate(cert CertificateResource, bundle bool) (CertificateResource, error) {
+	// Input certificate is PEM encoded. Decode it here as we may need the decoded
+	// cert later on in the renewal process. The input may be a bundle or a single certificate.
+	certificates, err := parsePEMBundle(cert.Certificate)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	x509Cert := certificates[0]
+	if x509Cert.IsCA {
+		return CertificateResource{}, fmt.Errorf("[%s] Certificate bundle starts with a CA certificate", cert.Domain)
+	}
+
+	// This is just meant to be informal for the user.
+	timeLeft := x509Cert.NotAfter.Sub(time.Now().UTC())
+	logf("[INFO][%s] acme: Trying renewal with %d hours remaining", cert.Domain, int(timeLeft.Hours()))
+
+	// The first step of renewal is to check if we get a renewed cert
+	// directly from the cert URL.
+	resp, err := httpGet(cert.CertURL)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+	defer resp.Body.Close()
+	serverCertBytes, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	serverCert, err := x509.ParseCertificate(serverCertBytes)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	// If the server responds with a different certificate we are effectively renewed.
+	// TODO: Further test if we can actually use the new certificate (Our private key works)
+	if !x509Cert.Equal(serverCert) {
+		logf("[INFO][%s] acme: Server responded with renewed certificate", cert.Domain)
+		issuedCert := pemEncode(derCertificateBytes(serverCertBytes))
+		// If bundle is true, we want to return a certificate bundle.
+		// To do this, we need the issuer certificate.
+		if bundle {
+			// The issuer certificate link is always supplied via an "up" link
+			// in the response headers of a new certificate.
+			links := parseLinks(resp.Header["Link"])
+			issuerCert, err := c.getIssuerCertificate(links["up"])
+			if err != nil {
+				// If we fail to acquire the issuer cert, return the issued certificate - do not fail.
+				logf("[ERROR][%s] acme: Could not bundle issuer certificate: %v", cert.Domain, err)
+			} else {
+				// Success - append the issuer cert to the issued cert.
+				issuerCert = pemEncode(derCertificateBytes(issuerCert))
+				issuedCert = append(issuedCert, issuerCert...)
+			}
+		}
+
+		cert.Certificate = issuedCert
+		return cert, nil
+	}
+
+	var privKey crypto.PrivateKey
+	if cert.PrivateKey != nil {
+		privKey, err = parsePEMPrivateKey(cert.PrivateKey)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+	}
+
+	var domains []string
+	var failures map[string]error
+	// check for SAN certificate
+	if len(x509Cert.DNSNames) > 1 {
+		domains = append(domains, x509Cert.Subject.CommonName)
+		for _, sanDomain := range x509Cert.DNSNames {
+			if sanDomain == x509Cert.Subject.CommonName {
+				continue
+			}
+			domains = append(domains, sanDomain)
+		}
+	} else {
+		domains = append(domains, x509Cert.Subject.CommonName)
+	}
+
+	newCert, failures := c.ObtainCertificate(domains, bundle, privKey)
+	return newCert, failures[cert.Domain]
+}
+
+// Looks through the challenge combinations to find a solvable match.
+// Then solves the challenges in series and returns.
+func (c *Client) solveChallenges(challenges []authorizationResource) map[string]error {
+	// loop through the resources, basically through the domains.
+	failures := make(map[string]error)
+	for _, authz := range challenges {
+		// no solvers - no solving
+		if solvers := c.chooseSolvers(authz.Body, authz.Domain); solvers != nil {
+			for i, solver := range solvers {
+				// TODO: do not immediately fail if one domain fails to validate.
+				err := solver.Solve(authz.Body.Challenges[i], authz.Domain)
+				if err != nil {
+					failures[authz.Domain] = err
+				}
+			}
+		} else {
+			failures[authz.Domain] = fmt.Errorf("[%s] acme: Could not determine solvers", authz.Domain)
+		}
+	}
+
+	return failures
+}
+
+// Checks all combinations from the server and returns an array of
+// solvers which should get executed in series.
+func (c *Client) chooseSolvers(auth authorization, domain string) map[int]solver {
+	for _, combination := range auth.Combinations {
+		solvers := make(map[int]solver)
+		for _, idx := range combination {
+			if solver, ok := c.solvers[auth.Challenges[idx].Type]; ok {
+				solvers[idx] = solver
+			} else {
+				logf("[INFO][%s] acme: Could not find solver for: %s", domain, auth.Challenges[idx].Type)
+			}
+		}
+
+		// If we can solve the whole combination, return the solvers
+		if len(solvers) == len(combination) {
+			return solvers
+		}
+	}
+	return nil
+}
+
+// Get the challenges needed to proof our identifier to the ACME server.
+func (c *Client) getChallenges(domains []string) ([]authorizationResource, map[string]error) {
+	resc, errc := make(chan authorizationResource), make(chan domainError)
+
+	for _, domain := range domains {
+		go func(domain string) {
+			authMsg := authorization{Resource: "new-authz", Identifier: identifier{Type: "dns", Value: domain}}
+			var authz authorization
+			hdr, err := postJSON(c.jws, c.user.GetRegistration().NewAuthzURL, authMsg, &authz)
+			if err != nil {
+				errc <- domainError{Domain: domain, Error: err}
+				return
+			}
+
+			links := parseLinks(hdr["Link"])
+			if links["next"] == "" {
+				logf("[ERROR][%s] acme: Server did not provide next link to proceed", domain)
+				return
+			}
+
+			resc <- authorizationResource{Body: authz, NewCertURL: links["next"], AuthURL: hdr.Get("Location"), Domain: domain}
+		}(domain)
+	}
+
+	responses := make(map[string]authorizationResource)
+	failures := make(map[string]error)
+	for i := 0; i < len(domains); i++ {
+		select {
+		case res := <-resc:
+			responses[res.Domain] = res
+		case err := <-errc:
+			failures[err.Domain] = err.Error
+		}
+	}
+
+	challenges := make([]authorizationResource, 0, len(responses))
+	for _, domain := range domains {
+		if challenge, ok := responses[domain]; ok {
+			challenges = append(challenges, challenge)
+		}
+	}
+
+	close(resc)
+	close(errc)
+
+	return challenges, failures
+}
+
+func (c *Client) requestCertificate(authz []authorizationResource, bundle bool, privKey crypto.PrivateKey) (CertificateResource, error) {
+	if len(authz) == 0 {
+		return CertificateResource{}, errors.New("Passed no authorizations to requestCertificate!")
+	}
+
+	commonName := authz[0]
+	var err error
+	if privKey == nil {
+		privKey, err = generatePrivateKey(c.keyType)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+	}
+
+	var san []string
+	var authURLs []string
+	for _, auth := range authz[1:] {
+		san = append(san, auth.Domain)
+		authURLs = append(authURLs, auth.AuthURL)
+	}
+
+	// TODO: should the CSR be customizable?
+	csr, err := generateCsr(privKey, commonName.Domain, san)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	csrString := base64.URLEncoding.EncodeToString(csr)
+	jsonBytes, err := json.Marshal(csrMessage{Resource: "new-cert", Csr: csrString, Authorizations: authURLs})
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	resp, err := c.jws.post(commonName.NewCertURL, jsonBytes)
+	if err != nil {
+		return CertificateResource{}, err
+	}
+
+	privateKeyPem := pemEncode(privKey)
+	cerRes := CertificateResource{
+		Domain:     commonName.Domain,
+		CertURL:    resp.Header.Get("Location"),
+		PrivateKey: privateKeyPem}
+
+	for {
+		switch resp.StatusCode {
+		case 201, 202:
+			cert, err := ioutil.ReadAll(limitReader(resp.Body, 1024*1024))
+			resp.Body.Close()
+			if err != nil {
+				return CertificateResource{}, err
+			}
+
+			// The server returns a body with a length of zero if the
+			// certificate was not ready at the time this request completed.
+			// Otherwise the body is the certificate.
+			if len(cert) > 0 {
+
+				cerRes.CertStableURL = resp.Header.Get("Content-Location")
+				cerRes.AccountRef = c.user.GetRegistration().URI
+
+				issuedCert := pemEncode(derCertificateBytes(cert))
+				// If bundle is true, we want to return a certificate bundle.
+				// To do this, we need the issuer certificate.
+				if bundle {
+					// The issuer certificate link is always supplied via an "up" link
+					// in the response headers of a new certificate.
+					links := parseLinks(resp.Header["Link"])
+					issuerCert, err := c.getIssuerCertificate(links["up"])
+					if err != nil {
+						// If we fail to acquire the issuer cert, return the issued certificate - do not fail.
+						logf("[WARNING][%s] acme: Could not bundle issuer certificate: %v", commonName.Domain, err)
+					} else {
+						// Success - append the issuer cert to the issued cert.
+						issuerCert = pemEncode(derCertificateBytes(issuerCert))
+						issuedCert = append(issuedCert, issuerCert...)
+					}
+				}
+
+				cerRes.Certificate = issuedCert
+				logf("[INFO][%s] Server responded with a certificate.", commonName.Domain)
+				return cerRes, nil
+			}
+
+			// The certificate was granted but is not yet issued.
+			// Check retry-after and loop.
+			ra := resp.Header.Get("Retry-After")
+			retryAfter, err := strconv.Atoi(ra)
+			if err != nil {
+				return CertificateResource{}, err
+			}
+
+			logf("[INFO][%s] acme: Server responded with status 202; retrying after %ds", commonName.Domain, retryAfter)
+			time.Sleep(time.Duration(retryAfter) * time.Second)
+
+			break
+		default:
+			return CertificateResource{}, handleHTTPError(resp)
+		}
+
+		resp, err = httpGet(cerRes.CertURL)
+		if err != nil {
+			return CertificateResource{}, err
+		}
+	}
+}
+
+// getIssuerCertificate requests the issuer certificate and caches it for
+// subsequent requests.
+func (c *Client) getIssuerCertificate(url string) ([]byte, error) {
+	logf("[INFO] acme: Requesting issuer cert from %s", url)
+	if c.issuerCert != nil {
+		return c.issuerCert, nil
+	}
+
+	resp, err := httpGet(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	issuerBytes, err := ioutil.ReadAll(limitReader(resp.Body, 1024*1024))
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = x509.ParseCertificate(issuerBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	c.issuerCert = issuerBytes
+	return issuerBytes, err
+}
+
+func parseLinks(links []string) map[string]string {
+	aBrkt := regexp.MustCompile("[<>]")
+	slver := regexp.MustCompile("(.+) *= *\"(.+)\"")
+	linkMap := make(map[string]string)
+
+	for _, link := range links {
+
+		link = aBrkt.ReplaceAllString(link, "")
+		parts := strings.Split(link, ";")
+
+		matches := slver.FindStringSubmatch(parts[1])
+		if len(matches) > 0 {
+			linkMap[matches[2]] = parts[0]
+		}
+	}
+
+	return linkMap
+}
+
+// validate makes the ACME server start validating a
+// challenge response, only returning once it is done.
+func validate(j *jws, domain, uri string, chlng challenge) error {
+	var challengeResponse challenge
+
+	hdr, err := postJSON(j, uri, chlng, &challengeResponse)
+	if err != nil {
+		return err
+	}
+
+	// After the path is sent, the ACME server will access our server.
+	// Repeatedly check the server for an updated status on our request.
+	for {
+		switch challengeResponse.Status {
+		case "valid":
+			logf("[INFO][%s] The server validated our request", domain)
+			return nil
+		case "pending":
+			break
+		case "invalid":
+			return handleChallengeError(challengeResponse)
+		default:
+			return errors.New("The server returned an unexpected state.")
+		}
+
+		ra, err := strconv.Atoi(hdr.Get("Retry-After"))
+		if err != nil {
+			// The ACME server MUST return a Retry-After.
+			// If it doesn't, we'll just poll hard.
+			ra = 1
+		}
+		time.Sleep(time.Duration(ra) * time.Second)
+
+		hdr, err = getJSON(uri, &challengeResponse)
+		if err != nil {
+			return err
+		}
+	}
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/client_test.go

@@ -0,0 +1,198 @@
+package acme
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/json"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestNewClient(t *testing.T) {
+	keyBits := 32 // small value keeps test fast
+	keyType := RSA2048
+	key, err := rsa.GenerateKey(rand.Reader, keyBits)
+	if err != nil {
+		t.Fatal("Could not generate test key:", err)
+	}
+	user := mockUser{
+		email:      "test@test.com",
+		regres:     new(RegistrationResource),
+		privatekey: key,
+	}
+
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		data, _ := json.Marshal(directory{NewAuthzURL: "http://test", NewCertURL: "http://test", NewRegURL: "http://test", RevokeCertURL: "http://test"})
+		w.Write(data)
+	}))
+
+	client, err := NewClient(ts.URL, user, keyType)
+	if err != nil {
+		t.Fatalf("Could not create client: %v", err)
+	}
+
+	if client.jws == nil {
+		t.Fatalf("Expected client.jws to not be nil")
+	}
+	if expected, actual := key, client.jws.privKey; actual != expected {
+		t.Errorf("Expected jws.privKey to be %p but was %p", expected, actual)
+	}
+
+	if client.keyType != keyType {
+		t.Errorf("Expected keyType to be %s but was %s", keyType, client.keyType)
+	}
+
+	if expected, actual := 2, len(client.solvers); actual != expected {
+		t.Fatalf("Expected %d solver(s), got %d", expected, actual)
+	}
+}
+
+func TestClientOptPort(t *testing.T) {
+	keyBits := 32 // small value keeps test fast
+	key, err := rsa.GenerateKey(rand.Reader, keyBits)
+	if err != nil {
+		t.Fatal("Could not generate test key:", err)
+	}
+	user := mockUser{
+		email:      "test@test.com",
+		regres:     new(RegistrationResource),
+		privatekey: key,
+	}
+
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		data, _ := json.Marshal(directory{NewAuthzURL: "http://test", NewCertURL: "http://test", NewRegURL: "http://test", RevokeCertURL: "http://test"})
+		w.Write(data)
+	}))
+
+	optPort := "1234"
+	optHost := ""
+	client, err := NewClient(ts.URL, user, RSA2048)
+	if err != nil {
+		t.Fatalf("Could not create client: %v", err)
+	}
+	client.SetHTTPAddress(net.JoinHostPort(optHost, optPort))
+	client.SetTLSAddress(net.JoinHostPort(optHost, optPort))
+
+	httpSolver, ok := client.solvers[HTTP01].(*httpChallenge)
+	if !ok {
+		t.Fatal("Expected http-01 solver to be httpChallenge type")
+	}
+	if httpSolver.jws != client.jws {
+		t.Error("Expected http-01 to have same jws as client")
+	}
+	if got := httpSolver.provider.(*HTTPProviderServer).port; got != optPort {
+		t.Errorf("Expected http-01 to have port %s but was %s", optPort, got)
+	}
+	if got := httpSolver.provider.(*HTTPProviderServer).iface; got != optHost {
+		t.Errorf("Expected http-01 to have iface %s but was %s", optHost, got)
+	}
+
+	httpsSolver, ok := client.solvers[TLSSNI01].(*tlsSNIChallenge)
+	if !ok {
+		t.Fatal("Expected tls-sni-01 solver to be httpChallenge type")
+	}
+	if httpsSolver.jws != client.jws {
+		t.Error("Expected tls-sni-01 to have same jws as client")
+	}
+	if got := httpsSolver.provider.(*TLSProviderServer).port; got != optPort {
+		t.Errorf("Expected tls-sni-01 to have port %s but was %s", optPort, got)
+	}
+	if got := httpsSolver.provider.(*TLSProviderServer).iface; got != optHost {
+		t.Errorf("Expected tls-sni-01 to have port %s but was %s", optHost, got)
+	}
+
+	// test setting different host
+	optHost = "127.0.0.1"
+	client.SetHTTPAddress(net.JoinHostPort(optHost, optPort))
+	client.SetTLSAddress(net.JoinHostPort(optHost, optPort))
+
+	if got := httpSolver.provider.(*HTTPProviderServer).iface; got != optHost {
+		t.Errorf("Expected http-01 to have iface %s but was %s", optHost, got)
+	}
+	if got := httpsSolver.provider.(*TLSProviderServer).port; got != optPort {
+		t.Errorf("Expected tls-sni-01 to have port %s but was %s", optPort, got)
+	}
+}
+
+func TestValidate(t *testing.T) {
+	var statuses []string
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Minimal stub ACME server for validation.
+		w.Header().Add("Replay-Nonce", "12345")
+		w.Header().Add("Retry-After", "0")
+		switch r.Method {
+		case "HEAD":
+		case "POST":
+			st := statuses[0]
+			statuses = statuses[1:]
+			writeJSONResponse(w, &challenge{Type: "http-01", Status: st, URI: "http://example.com/", Token: "token"})
+
+		case "GET":
+			st := statuses[0]
+			statuses = statuses[1:]
+			writeJSONResponse(w, &challenge{Type: "http-01", Status: st, URI: "http://example.com/", Token: "token"})
+
+		default:
+			http.Error(w, r.Method, http.StatusMethodNotAllowed)
+		}
+	}))
+	defer ts.Close()
+
+	privKey, _ := rsa.GenerateKey(rand.Reader, 512)
+	j := &jws{privKey: privKey, directoryURL: ts.URL}
+
+	tsts := []struct {
+		name     string
+		statuses []string
+		want     string
+	}{
+		{"POST-unexpected", []string{"weird"}, "unexpected"},
+		{"POST-valid", []string{"valid"}, ""},
+		{"POST-invalid", []string{"invalid"}, "Error Detail"},
+		{"GET-unexpected", []string{"pending", "weird"}, "unexpected"},
+		{"GET-valid", []string{"pending", "valid"}, ""},
+		{"GET-invalid", []string{"pending", "invalid"}, "Error Detail"},
+	}
+
+	for _, tst := range tsts {
+		statuses = tst.statuses
+		if err := validate(j, "example.com", ts.URL, challenge{Type: "http-01", Token: "token"}); err == nil && tst.want != "" {
+			t.Errorf("[%s] validate: got error %v, want something with %q", tst.name, err, tst.want)
+		} else if err != nil && !strings.Contains(err.Error(), tst.want) {
+			t.Errorf("[%s] validate: got error %v, want something with %q", tst.name, err, tst.want)
+		}
+	}
+}
+
+// writeJSONResponse marshals the body as JSON and writes it to the response.
+func writeJSONResponse(w http.ResponseWriter, body interface{}) {
+	bs, err := json.Marshal(body)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if _, err := w.Write(bs); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}
+
+// stubValidate is like validate, except it does nothing.
+func stubValidate(j *jws, domain, uri string, chlng challenge) error {
+	return nil
+}
+
+type mockUser struct {
+	email      string
+	regres     *RegistrationResource
+	privatekey *rsa.PrivateKey
+}
+
+func (u mockUser) GetEmail() string                       { return u.email }
+func (u mockUser) GetRegistration() *RegistrationResource { return u.regres }
+func (u mockUser) GetPrivateKey() crypto.PrivateKey       { return u.privatekey }

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/crypto.go

@@ -0,0 +1,323 @@
+package acme
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/base64"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/big"
+	"net/http"
+	"strings"
+	"time"
+
+	"golang.org/x/crypto/ocsp"
+)
+
+// KeyType represents the key algo as well as the key size or curve to use.
+type KeyType string
+type derCertificateBytes []byte
+
+// Constants for all key types we support.
+const (
+	EC256   = KeyType("P256")
+	EC384   = KeyType("P384")
+	RSA2048 = KeyType("2048")
+	RSA4096 = KeyType("4096")
+	RSA8192 = KeyType("8192")
+)
+
+const (
+	// OCSPGood means that the certificate is valid.
+	OCSPGood = ocsp.Good
+	// OCSPRevoked means that the certificate has been deliberately revoked.
+	OCSPRevoked = ocsp.Revoked
+	// OCSPUnknown means that the OCSP responder doesn't know about the certificate.
+	OCSPUnknown = ocsp.Unknown
+	// OCSPServerFailed means that the OCSP responder failed to process the request.
+	OCSPServerFailed = ocsp.ServerFailed
+)
+
+// GetOCSPForCert takes a PEM encoded cert or cert bundle returning the raw OCSP response,
+// the parsed response, and an error, if any. The returned []byte can be passed directly
+// into the OCSPStaple property of a tls.Certificate. If the bundle only contains the
+// issued certificate, this function will try to get the issuer certificate from the
+// IssuingCertificateURL in the certificate. If the []byte and/or ocsp.Response return
+// values are nil, the OCSP status may be assumed OCSPUnknown.
+func GetOCSPForCert(bundle []byte) ([]byte, *ocsp.Response, error) {
+	certificates, err := parsePEMBundle(bundle)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// We expect the certificate slice to be ordered downwards the chain.
+	// SRV CRT -> CA. We need to pull the leaf and issuer certs out of it,
+	// which should always be the first two certificates. If there's no
+	// OCSP server listed in the leaf cert, there's nothing to do. And if
+	// we have only one certificate so far, we need to get the issuer cert.
+	issuedCert := certificates[0]
+	if len(issuedCert.OCSPServer) == 0 {
+		return nil, nil, errors.New("no OCSP server specified in cert")
+	}
+	if len(certificates) == 1 {
+		// TODO: build fallback. If this fails, check the remaining array entries.
+		if len(issuedCert.IssuingCertificateURL) == 0 {
+			return nil, nil, errors.New("no issuing certificate URL")
+		}
+
+		resp, err := httpGet(issuedCert.IssuingCertificateURL[0])
+		if err != nil {
+			return nil, nil, err
+		}
+		defer resp.Body.Close()
+
+		issuerBytes, err := ioutil.ReadAll(limitReader(resp.Body, 1024*1024))
+		if err != nil {
+			return nil, nil, err
+		}
+
+		issuerCert, err := x509.ParseCertificate(issuerBytes)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		// Insert it into the slice on position 0
+		// We want it ordered right SRV CRT -> CA
+		certificates = append(certificates, issuerCert)
+	}
+	issuerCert := certificates[1]
+
+	// Finally kick off the OCSP request.
+	ocspReq, err := ocsp.CreateRequest(issuedCert, issuerCert, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	reader := bytes.NewReader(ocspReq)
+	req, err := httpPost(issuedCert.OCSPServer[0], "application/ocsp-request", reader)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer req.Body.Close()
+
+	ocspResBytes, err := ioutil.ReadAll(limitReader(req.Body, 1024*1024))
+	ocspRes, err := ocsp.ParseResponse(ocspResBytes, issuerCert)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if ocspRes.Certificate == nil {
+		err = ocspRes.CheckSignatureFrom(issuerCert)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	return ocspResBytes, ocspRes, nil
+}
+
+func getKeyAuthorization(token string, key interface{}) (string, error) {
+	var publicKey crypto.PublicKey
+	switch k := key.(type) {
+	case *ecdsa.PrivateKey:
+		publicKey = k.Public()
+	case *rsa.PrivateKey:
+		publicKey = k.Public()
+	}
+
+	// Generate the Key Authorization for the challenge
+	jwk := keyAsJWK(publicKey)
+	if jwk == nil {
+		return "", errors.New("Could not generate JWK from key.")
+	}
+	thumbBytes, err := jwk.Thumbprint(crypto.SHA256)
+	if err != nil {
+		return "", err
+	}
+
+	// unpad the base64URL
+	keyThumb := base64.URLEncoding.EncodeToString(thumbBytes)
+	index := strings.Index(keyThumb, "=")
+	if index != -1 {
+		keyThumb = keyThumb[:index]
+	}
+
+	return token + "." + keyThumb, nil
+}
+
+// parsePEMBundle parses a certificate bundle from top to bottom and returns
+// a slice of x509 certificates. This function will error if no certificates are found.
+func parsePEMBundle(bundle []byte) ([]*x509.Certificate, error) {
+	var certificates []*x509.Certificate
+	var certDERBlock *pem.Block
+
+	for {
+		certDERBlock, bundle = pem.Decode(bundle)
+		if certDERBlock == nil {
+			break
+		}
+
+		if certDERBlock.Type == "CERTIFICATE" {
+			cert, err := x509.ParseCertificate(certDERBlock.Bytes)
+			if err != nil {
+				return nil, err
+			}
+			certificates = append(certificates, cert)
+		}
+	}
+
+	if len(certificates) == 0 {
+		return nil, errors.New("No certificates were found while parsing the bundle.")
+	}
+
+	return certificates, nil
+}
+
+func parsePEMPrivateKey(key []byte) (crypto.PrivateKey, error) {
+	keyBlock, _ := pem.Decode(key)
+
+	switch keyBlock.Type {
+	case "RSA PRIVATE KEY":
+		return x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
+	case "EC PRIVATE KEY":
+		return x509.ParseECPrivateKey(keyBlock.Bytes)
+	default:
+		return nil, errors.New("Unknown PEM header value")
+	}
+}
+
+func generatePrivateKey(keyType KeyType) (crypto.PrivateKey, error) {
+
+	switch keyType {
+	case EC256:
+		return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	case EC384:
+		return ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+	case RSA2048:
+		return rsa.GenerateKey(rand.Reader, 2048)
+	case RSA4096:
+		return rsa.GenerateKey(rand.Reader, 4096)
+	case RSA8192:
+		return rsa.GenerateKey(rand.Reader, 8192)
+	}
+
+	return nil, fmt.Errorf("Invalid KeyType: %s", keyType)
+}
+
+func generateCsr(privateKey crypto.PrivateKey, domain string, san []string) ([]byte, error) {
+	template := x509.CertificateRequest{
+		Subject: pkix.Name{
+			CommonName: domain,
+		},
+	}
+
+	if len(san) > 0 {
+		template.DNSNames = san
+	}
+
+	return x509.CreateCertificateRequest(rand.Reader, &template, privateKey)
+}
+
+func pemEncode(data interface{}) []byte {
+	var pemBlock *pem.Block
+	switch key := data.(type) {
+	case *ecdsa.PrivateKey:
+		keyBytes, _ := x509.MarshalECPrivateKey(key)
+		pemBlock = &pem.Block{Type: "EC PRIVATE KEY", Bytes: keyBytes}
+	case *rsa.PrivateKey:
+		pemBlock = &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}
+		break
+	case derCertificateBytes:
+		pemBlock = &pem.Block{Type: "CERTIFICATE", Bytes: []byte(data.(derCertificateBytes))}
+	}
+
+	return pem.EncodeToMemory(pemBlock)
+}
+
+func pemDecode(data []byte) (*pem.Block, error) {
+	pemBlock, _ := pem.Decode(data)
+	if pemBlock == nil {
+		return nil, fmt.Errorf("Pem decode did not yield a valid block. Is the certificate in the right format?")
+	}
+
+	return pemBlock, nil
+}
+
+func pemDecodeTox509(pem []byte) (*x509.Certificate, error) {
+	pemBlock, err := pemDecode(pem)
+	if pemBlock == nil {
+		return nil, err
+	}
+
+	return x509.ParseCertificate(pemBlock.Bytes)
+}
+
+// GetPEMCertExpiration returns the "NotAfter" date of a PEM encoded certificate.
+// The certificate has to be PEM encoded. Any other encodings like DER will fail.
+func GetPEMCertExpiration(cert []byte) (time.Time, error) {
+	pemBlock, err := pemDecode(cert)
+	if pemBlock == nil {
+		return time.Time{}, err
+	}
+
+	return getCertExpiration(pemBlock.Bytes)
+}
+
+// getCertExpiration returns the "NotAfter" date of a DER encoded certificate.
+func getCertExpiration(cert []byte) (time.Time, error) {
+	pCert, err := x509.ParseCertificate(cert)
+	if err != nil {
+		return time.Time{}, err
+	}
+
+	return pCert.NotAfter, nil
+}
+
+func generatePemCert(privKey *rsa.PrivateKey, domain string) ([]byte, error) {
+	derBytes, err := generateDerCert(privKey, time.Time{}, domain)
+	if err != nil {
+		return nil, err
+	}
+
+	return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes}), nil
+}
+
+func generateDerCert(privKey *rsa.PrivateKey, expiration time.Time, domain string) ([]byte, error) {
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
+	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		return nil, err
+	}
+
+	if expiration.IsZero() {
+		expiration = time.Now().Add(365)
+	}
+
+	template := x509.Certificate{
+		SerialNumber: serialNumber,
+		Subject: pkix.Name{
+			CommonName: "ACME Challenge TEMP",
+		},
+		NotBefore: time.Now(),
+		NotAfter:  expiration,
+
+		KeyUsage:              x509.KeyUsageKeyEncipherment,
+		BasicConstraintsValid: true,
+		DNSNames:              []string{domain},
+	}
+
+	return x509.CreateCertificate(rand.Reader, &template, &template, &privKey.PublicKey, privKey)
+}
+
+func limitReader(rd io.ReadCloser, numBytes int64) io.ReadCloser {
+	return http.MaxBytesReader(nil, rd, numBytes)
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/crypto_test.go

@@ -0,0 +1,93 @@
+package acme
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"testing"
+	"time"
+)
+
+func TestGeneratePrivateKey(t *testing.T) {
+	key, err := generatePrivateKey(RSA2048)
+	if err != nil {
+		t.Error("Error generating private key:", err)
+	}
+	if key == nil {
+		t.Error("Expected key to not be nil, but it was")
+	}
+}
+
+func TestGenerateCSR(t *testing.T) {
+	key, err := rsa.GenerateKey(rand.Reader, 512)
+	if err != nil {
+		t.Fatal("Error generating private key:", err)
+	}
+
+	csr, err := generateCsr(key, "fizz.buzz", nil)
+	if err != nil {
+		t.Error("Error generating CSR:", err)
+	}
+	if csr == nil || len(csr) == 0 {
+		t.Error("Expected CSR with data, but it was nil or length 0")
+	}
+}
+
+func TestPEMEncode(t *testing.T) {
+	buf := bytes.NewBufferString("TestingRSAIsSoMuchFun")
+
+	reader := MockRandReader{b: buf}
+	key, err := rsa.GenerateKey(reader, 32)
+	if err != nil {
+		t.Fatal("Error generating private key:", err)
+	}
+
+	data := pemEncode(key)
+
+	if data == nil {
+		t.Fatal("Expected result to not be nil, but it was")
+	}
+	if len(data) != 127 {
+		t.Errorf("Expected PEM encoding to be length 127, but it was %d", len(data))
+	}
+}
+
+func TestPEMCertExpiration(t *testing.T) {
+	privKey, err := generatePrivateKey(RSA2048)
+	if err != nil {
+		t.Fatal("Error generating private key:", err)
+	}
+
+	expiration := time.Now().Add(365)
+	expiration = expiration.Round(time.Second)
+	certBytes, err := generateDerCert(privKey.(*rsa.PrivateKey), expiration, "test.com")
+	if err != nil {
+		t.Fatal("Error generating cert:", err)
+	}
+
+	buf := bytes.NewBufferString("TestingRSAIsSoMuchFun")
+
+	// Some random string should return an error.
+	if ctime, err := GetPEMCertExpiration(buf.Bytes()); err == nil {
+		t.Errorf("Expected getCertExpiration to return an error for garbage string but returned %v", ctime)
+	}
+
+	// A DER encoded certificate should return an error.
+	if _, err := GetPEMCertExpiration(certBytes); err == nil {
+		t.Errorf("Expected getCertExpiration to return an error for DER certificates but returned none.")
+	}
+
+	// A PEM encoded certificate should work ok.
+	pemCert := pemEncode(derCertificateBytes(certBytes))
+	if ctime, err := GetPEMCertExpiration(pemCert); err != nil || !ctime.Equal(expiration.UTC()) {
+		t.Errorf("Expected getCertExpiration to return %v but returned %v. Error: %v", expiration, ctime, err)
+	}
+}
+
+type MockRandReader struct {
+	b *bytes.Buffer
+}
+
+func (r MockRandReader) Read(p []byte) (int, error) {
+	return r.b.Read(p)
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/error.go

@@ -0,0 +1,73 @@
+package acme
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+const (
+	tosAgreementError = "Must agree to subscriber agreement before any further actions"
+)
+
+// RemoteError is the base type for all errors specific to the ACME protocol.
+type RemoteError struct {
+	StatusCode int    `json:"status,omitempty"`
+	Type       string `json:"type"`
+	Detail     string `json:"detail"`
+}
+
+func (e RemoteError) Error() string {
+	return fmt.Sprintf("acme: Error %d - %s - %s", e.StatusCode, e.Type, e.Detail)
+}
+
+// TOSError represents the error which is returned if the user needs to
+// accept the TOS.
+// TODO: include the new TOS url if we can somehow obtain it.
+type TOSError struct {
+	RemoteError
+}
+
+type domainError struct {
+	Domain string
+	Error  error
+}
+
+type challengeError struct {
+	RemoteError
+	records []validationRecord
+}
+
+func (c challengeError) Error() string {
+
+	var errStr string
+	for _, validation := range c.records {
+		errStr = errStr + fmt.Sprintf("\tValidation for %s:%s\n\tResolved to:\n\t\t%s\n\tUsed: %s\n\n",
+			validation.Hostname, validation.Port, strings.Join(validation.ResolvedAddresses, "\n\t\t"), validation.UsedAddress)
+	}
+
+	return fmt.Sprintf("%s\nError Detail:\n%s", c.RemoteError.Error(), errStr)
+}
+
+func handleHTTPError(resp *http.Response) error {
+	var errorDetail RemoteError
+	decoder := json.NewDecoder(resp.Body)
+	err := decoder.Decode(&errorDetail)
+	if err != nil {
+		return err
+	}
+
+	errorDetail.StatusCode = resp.StatusCode
+
+	// Check for errors we handle specifically
+	if errorDetail.StatusCode == http.StatusForbidden && errorDetail.Detail == tosAgreementError {
+		return TOSError{errorDetail}
+	}
+
+	return errorDetail
+}
+
+func handleChallengeError(chlng challenge) error {
+	return challengeError{chlng.Error, chlng.ValidationRecords}
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/http.go

@@ -0,0 +1,117 @@
+package acme
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"runtime"
+	"strings"
+	"time"
+)
+
+// UserAgent (if non-empty) will be tacked onto the User-Agent string in requests.
+var UserAgent string
+
+// defaultClient is an HTTP client with a reasonable timeout value.
+var defaultClient = http.Client{Timeout: 10 * time.Second}
+
+const (
+	// defaultGoUserAgent is the Go HTTP package user agent string. Too
+	// bad it isn't exported. If it changes, we should update it here, too.
+	defaultGoUserAgent = "Go-http-client/1.1"
+
+	// ourUserAgent is the User-Agent of this underlying library package.
+	ourUserAgent = "xenolf-acme"
+)
+
+// httpHead performs a HEAD request with a proper User-Agent string.
+// The response body (resp.Body) is already closed when this function returns.
+func httpHead(url string) (resp *http.Response, err error) {
+	req, err := http.NewRequest("HEAD", url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("User-Agent", userAgent())
+
+	resp, err = defaultClient.Do(req)
+	if err != nil {
+		return resp, err
+	}
+	resp.Body.Close()
+	return resp, err
+}
+
+// httpPost performs a POST request with a proper User-Agent string.
+// Callers should close resp.Body when done reading from it.
+func httpPost(url string, bodyType string, body io.Reader) (resp *http.Response, err error) {
+	req, err := http.NewRequest("POST", url, body)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", bodyType)
+	req.Header.Set("User-Agent", userAgent())
+
+	return defaultClient.Do(req)
+}
+
+// httpGet performs a GET request with a proper User-Agent string.
+// Callers should close resp.Body when done reading from it.
+func httpGet(url string) (resp *http.Response, err error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("User-Agent", userAgent())
+
+	return defaultClient.Do(req)
+}
+
+// getJSON performs an HTTP GET request and parses the response body
+// as JSON, into the provided respBody object.
+func getJSON(uri string, respBody interface{}) (http.Header, error) {
+	resp, err := httpGet(uri)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get %q: %v", uri, err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= http.StatusBadRequest {
+		return resp.Header, handleHTTPError(resp)
+	}
+
+	return resp.Header, json.NewDecoder(resp.Body).Decode(respBody)
+}
+
+// postJSON performs an HTTP POST request and parses the response body
+// as JSON, into the provided respBody object.
+func postJSON(j *jws, uri string, reqBody, respBody interface{}) (http.Header, error) {
+	jsonBytes, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, errors.New("Failed to marshal network message...")
+	}
+
+	resp, err := j.post(uri, jsonBytes)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to post JWS message. -> %v", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= http.StatusBadRequest {
+		return resp.Header, handleHTTPError(resp)
+	}
+
+	if respBody == nil {
+		return resp.Header, nil
+	}
+
+	return resp.Header, json.NewDecoder(resp.Body).Decode(respBody)
+}
+
+// userAgent builds and returns the User-Agent string to use in requests.
+func userAgent() string {
+	ua := fmt.Sprintf("%s (%s; %s) %s %s", defaultGoUserAgent, runtime.GOOS, runtime.GOARCH, ourUserAgent, UserAgent)
+	return strings.TrimSpace(ua)
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/http_challenge.go

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

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/http_challenge_server.go

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

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/http_challenge_test.go

@@ -0,0 +1,57 @@
+package acme
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"io/ioutil"
+	"strings"
+	"testing"
+)
+
+func TestHTTPChallenge(t *testing.T) {
+	privKey, _ := rsa.GenerateKey(rand.Reader, 512)
+	j := &jws{privKey: privKey}
+	clientChallenge := challenge{Type: HTTP01, Token: "http1"}
+	mockValidate := func(_ *jws, _, _ string, chlng challenge) error {
+		uri := "http://localhost:23457/.well-known/acme-challenge/" + chlng.Token
+		resp, err := httpGet(uri)
+		if err != nil {
+			return err
+		}
+		defer resp.Body.Close()
+
+		if want := "text/plain"; resp.Header.Get("Content-Type") != want {
+			t.Errorf("Get(%q) Content-Type: got %q, want %q", uri, resp.Header.Get("Content-Type"), want)
+		}
+
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			return err
+		}
+		bodyStr := string(body)
+
+		if bodyStr != chlng.KeyAuthorization {
+			t.Errorf("Get(%q) Body: got %q, want %q", uri, bodyStr, chlng.KeyAuthorization)
+		}
+
+		return nil
+	}
+	solver := &httpChallenge{jws: j, validate: mockValidate, provider: &HTTPProviderServer{port: "23457"}}
+
+	if err := solver.Solve(clientChallenge, "localhost:23457"); err != nil {
+		t.Errorf("Solve error: got %v, want nil", err)
+	}
+}
+
+func TestHTTPChallengeInvalidPort(t *testing.T) {
+	privKey, _ := rsa.GenerateKey(rand.Reader, 128)
+	j := &jws{privKey: privKey}
+	clientChallenge := challenge{Type: HTTP01, Token: "http2"}
+	solver := &httpChallenge{jws: j, validate: stubValidate, provider: &HTTPProviderServer{port: "123456"}}
+
+	if err := solver.Solve(clientChallenge, "localhost:123456"); err == nil {
+		t.Errorf("Solve error: got %v, want error", err)
+	} else if want := "invalid port 123456"; !strings.HasSuffix(err.Error(), want) {
+		t.Errorf("Solve error: got %q, want suffix %q", err.Error(), want)
+	}
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/http_test.go

@@ -0,0 +1,100 @@
+package acme
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestHTTPHeadUserAgent(t *testing.T) {
+	var ua, method string
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ua = r.Header.Get("User-Agent")
+		method = r.Method
+	}))
+	defer ts.Close()
+
+	_, err := httpHead(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if method != "HEAD" {
+		t.Errorf("Expected method to be HEAD, got %s", method)
+	}
+	if !strings.Contains(ua, ourUserAgent) {
+		t.Errorf("Expected User-Agent to contain '%s', got: '%s'", ourUserAgent, ua)
+	}
+}
+
+func TestHTTPGetUserAgent(t *testing.T) {
+	var ua, method string
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ua = r.Header.Get("User-Agent")
+		method = r.Method
+	}))
+	defer ts.Close()
+
+	res, err := httpGet(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	res.Body.Close()
+
+	if method != "GET" {
+		t.Errorf("Expected method to be GET, got %s", method)
+	}
+	if !strings.Contains(ua, ourUserAgent) {
+		t.Errorf("Expected User-Agent to contain '%s', got: '%s'", ourUserAgent, ua)
+	}
+}
+
+func TestHTTPPostUserAgent(t *testing.T) {
+	var ua, method string
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ua = r.Header.Get("User-Agent")
+		method = r.Method
+	}))
+	defer ts.Close()
+
+	res, err := httpPost(ts.URL, "text/plain", strings.NewReader("falalalala"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	res.Body.Close()
+
+	if method != "POST" {
+		t.Errorf("Expected method to be POST, got %s", method)
+	}
+	if !strings.Contains(ua, ourUserAgent) {
+		t.Errorf("Expected User-Agent to contain '%s', got: '%s'", ourUserAgent, ua)
+	}
+}
+
+func TestUserAgent(t *testing.T) {
+	ua := userAgent()
+
+	if !strings.Contains(ua, defaultGoUserAgent) {
+		t.Errorf("Expected UA to contain %s, got '%s'", defaultGoUserAgent, ua)
+	}
+	if !strings.Contains(ua, ourUserAgent) {
+		t.Errorf("Expected UA to contain %s, got '%s'", ourUserAgent, ua)
+	}
+	if strings.HasSuffix(ua, " ") {
+		t.Errorf("UA should not have trailing spaces; got '%s'", ua)
+	}
+
+	// customize the UA by appending a value
+	UserAgent = "MyApp/1.2.3"
+	ua = userAgent()
+	if !strings.Contains(ua, defaultGoUserAgent) {
+		t.Errorf("Expected UA to contain %s, got '%s'", defaultGoUserAgent, ua)
+	}
+	if !strings.Contains(ua, ourUserAgent) {
+		t.Errorf("Expected UA to contain %s, got '%s'", ourUserAgent, ua)
+	}
+	if !strings.Contains(ua, UserAgent) {
+		t.Errorf("Expected custom UA to contain %s, got '%s'", UserAgent, ua)
+	}
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/jws.go

@@ -0,0 +1,107 @@
+package acme
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"fmt"
+	"net/http"
+
+	"gopkg.in/square/go-jose.v1"
+)
+
+type jws struct {
+	directoryURL string
+	privKey      crypto.PrivateKey
+	nonces       []string
+}
+
+func keyAsJWK(key interface{}) *jose.JsonWebKey {
+	switch k := key.(type) {
+	case *ecdsa.PublicKey:
+		return &jose.JsonWebKey{Key: k, Algorithm: "EC"}
+	case *rsa.PublicKey:
+		return &jose.JsonWebKey{Key: k, Algorithm: "RSA"}
+
+	default:
+		return nil
+	}
+}
+
+// Posts a JWS signed message to the specified URL
+func (j *jws) post(url string, content []byte) (*http.Response, error) {
+	signedContent, err := j.signContent(content)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := httpPost(url, "application/jose+json", bytes.NewBuffer([]byte(signedContent.FullSerialize())))
+	if err != nil {
+		return nil, err
+	}
+
+	j.getNonceFromResponse(resp)
+
+	return resp, err
+}
+
+func (j *jws) signContent(content []byte) (*jose.JsonWebSignature, error) {
+
+	var alg jose.SignatureAlgorithm
+	switch k := j.privKey.(type) {
+	case *rsa.PrivateKey:
+		alg = jose.RS256
+	case *ecdsa.PrivateKey:
+		if k.Curve == elliptic.P256() {
+			alg = jose.ES256
+		} else if k.Curve == elliptic.P384() {
+			alg = jose.ES384
+		}
+	}
+
+	signer, err := jose.NewSigner(alg, j.privKey)
+	if err != nil {
+		return nil, err
+	}
+	signer.SetNonceSource(j)
+
+	signed, err := signer.Sign(content)
+	if err != nil {
+		return nil, err
+	}
+	return signed, nil
+}
+
+func (j *jws) getNonceFromResponse(resp *http.Response) error {
+	nonce := resp.Header.Get("Replay-Nonce")
+	if nonce == "" {
+		return fmt.Errorf("Server did not respond with a proper nonce header.")
+	}
+
+	j.nonces = append(j.nonces, nonce)
+	return nil
+}
+
+func (j *jws) getNonce() error {
+	resp, err := httpHead(j.directoryURL)
+	if err != nil {
+		return err
+	}
+
+	return j.getNonceFromResponse(resp)
+}
+
+func (j *jws) Nonce() (string, error) {
+	nonce := ""
+	if len(j.nonces) == 0 {
+		err := j.getNonce()
+		if err != nil {
+			return nonce, err
+		}
+	}
+
+	nonce, j.nonces = j.nonces[len(j.nonces)-1], j.nonces[:len(j.nonces)-1]
+	return nonce, nil
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/messages.go

@@ -0,0 +1,115 @@
+package acme
+
+import (
+	"time"
+
+	"gopkg.in/square/go-jose.v1"
+)
+
+type directory struct {
+	NewAuthzURL   string `json:"new-authz"`
+	NewCertURL    string `json:"new-cert"`
+	NewRegURL     string `json:"new-reg"`
+	RevokeCertURL string `json:"revoke-cert"`
+}
+
+type recoveryKeyMessage struct {
+	Length int             `json:"length,omitempty"`
+	Client jose.JsonWebKey `json:"client,omitempty"`
+	Server jose.JsonWebKey `json:"client,omitempty"`
+}
+
+type registrationMessage struct {
+	Resource string   `json:"resource"`
+	Contact  []string `json:"contact"`
+	//	RecoveryKey recoveryKeyMessage `json:"recoveryKey,omitempty"`
+}
+
+// Registration is returned by the ACME server after the registration
+// The client implementation should save this registration somewhere.
+type Registration struct {
+	Resource       string          `json:"resource,omitempty"`
+	ID             int             `json:"id"`
+	Key            jose.JsonWebKey `json:"key"`
+	Contact        []string        `json:"contact"`
+	Agreement      string          `json:"agreement,omitempty"`
+	Authorizations string          `json:"authorizations,omitempty"`
+	Certificates   string          `json:"certificates,omitempty"`
+	//	RecoveryKey    recoveryKeyMessage `json:"recoveryKey,omitempty"`
+}
+
+// RegistrationResource represents all important informations about a registration
+// of which the client needs to keep track itself.
+type RegistrationResource struct {
+	Body        Registration `json:"body,omitempty"`
+	URI         string       `json:"uri,omitempty"`
+	NewAuthzURL string       `json:"new_authzr_uri,omitempty"`
+	TosURL      string       `json:"terms_of_service,omitempty"`
+}
+
+type authorizationResource struct {
+	Body       authorization
+	Domain     string
+	NewCertURL string
+	AuthURL    string
+}
+
+type authorization struct {
+	Resource     string      `json:"resource,omitempty"`
+	Identifier   identifier  `json:"identifier"`
+	Status       string      `json:"status,omitempty"`
+	Expires      time.Time   `json:"expires,omitempty"`
+	Challenges   []challenge `json:"challenges,omitempty"`
+	Combinations [][]int     `json:"combinations,omitempty"`
+}
+
+type identifier struct {
+	Type  string `json:"type"`
+	Value string `json:"value"`
+}
+
+type validationRecord struct {
+	URI               string   `json:"url,omitempty"`
+	Hostname          string   `json:"hostname,omitempty"`
+	Port              string   `json:"port,omitempty"`
+	ResolvedAddresses []string `json:"addressesResolved,omitempty"`
+	UsedAddress       string   `json:"addressUsed,omitempty"`
+}
+
+type challenge struct {
+	Resource          string             `json:"resource,omitempty"`
+	Type              Challenge          `json:"type,omitempty"`
+	Status            string             `json:"status,omitempty"`
+	URI               string             `json:"uri,omitempty"`
+	Token             string             `json:"token,omitempty"`
+	KeyAuthorization  string             `json:"keyAuthorization,omitempty"`
+	TLS               bool               `json:"tls,omitempty"`
+	Iterations        int                `json:"n,omitempty"`
+	Error             RemoteError        `json:"error,omitempty"`
+	ValidationRecords []validationRecord `json:"validationRecord,omitempty"`
+}
+
+type csrMessage struct {
+	Resource       string   `json:"resource,omitempty"`
+	Csr            string   `json:"csr"`
+	Authorizations []string `json:"authorizations"`
+}
+
+type revokeCertMessage struct {
+	Resource    string `json:"resource"`
+	Certificate string `json:"certificate"`
+}
+
+// CertificateResource represents a CA issued certificate.
+// PrivateKey and Certificate are both already PEM encoded
+// and can be directly written to disk. Certificate may
+// be a certificate bundle, depending on the options supplied
+// to create it.
+type CertificateResource struct {
+	Domain        string `json:"domain"`
+	CertURL       string `json:"certUrl"`
+	CertStableURL string `json:"certStableUrl"`
+	AccountRef    string `json:"accountRef,omitempty"`
+	PrivateKey    []byte `json:"-"`
+	Certificate   []byte `json:"-"`
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/provider.go

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

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/tls_sni_challenge.go

@@ -0,0 +1,73 @@
+package acme
+
+import (
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/tls"
+	"encoding/hex"
+	"fmt"
+	"log"
+)
+
+type tlsSNIChallenge struct {
+	jws      *jws
+	validate validateFunc
+	provider ChallengeProvider
+}
+
+func (t *tlsSNIChallenge) Solve(chlng challenge, domain string) error {
+	// FIXME: https://github.com/ietf-wg-acme/acme/pull/22
+	// Currently we implement this challenge to track boulder, not the current spec!
+
+	logf("[INFO][%s] acme: Trying to solve TLS-SNI-01", domain)
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := getKeyAuthorization(chlng.Token, t.jws.privKey)
+	if err != nil {
+		return err
+	}
+
+	err = t.provider.Present(domain, chlng.Token, keyAuth)
+	if err != nil {
+		return fmt.Errorf("[%s] error presenting token: %v", domain, err)
+	}
+	defer func() {
+		err := t.provider.CleanUp(domain, chlng.Token, keyAuth)
+		if err != nil {
+			log.Printf("[%s] error cleaning up: %v", domain, err)
+		}
+	}()
+	return t.validate(t.jws, domain, chlng.URI, challenge{Resource: "challenge", Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
+}
+
+// TLSSNI01ChallengeCert returns a certificate and target domain for the `tls-sni-01` challenge
+func TLSSNI01ChallengeCertDomain(keyAuth string) (tls.Certificate, string, error) {
+	// generate a new RSA key for the certificates
+	tempPrivKey, err := generatePrivateKey(RSA2048)
+	if err != nil {
+		return tls.Certificate{}, "", err
+	}
+	rsaPrivKey := tempPrivKey.(*rsa.PrivateKey)
+	rsaPrivPEM := pemEncode(rsaPrivKey)
+
+	zBytes := sha256.Sum256([]byte(keyAuth))
+	z := hex.EncodeToString(zBytes[:sha256.Size])
+	domain := fmt.Sprintf("%s.%s.acme.invalid", z[:32], z[32:])
+	tempCertPEM, err := generatePemCert(rsaPrivKey, domain)
+	if err != nil {
+		return tls.Certificate{}, "", err
+	}
+
+	certificate, err := tls.X509KeyPair(tempCertPEM, rsaPrivPEM)
+	if err != nil {
+		return tls.Certificate{}, "", err
+	}
+
+	return certificate, domain, nil
+}
+
+// TLSSNI01ChallengeCert returns a certificate for the `tls-sni-01` challenge
+func TLSSNI01ChallengeCert(keyAuth string) (tls.Certificate, error) {
+	cert, _, err := TLSSNI01ChallengeCertDomain(keyAuth)
+	return cert, err
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/tls_sni_challenge_server.go

@@ -0,0 +1,62 @@
+package acme
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net"
+	"net/http"
+)
+
+// TLSProviderServer implements ChallengeProvider for `TLS-SNI-01` challenge
+// It may be instantiated without using the NewTLSProviderServer function if
+// you want only to use the default values.
+type TLSProviderServer struct {
+	iface    string
+	port     string
+	done     chan bool
+	listener net.Listener
+}
+
+// NewTLSProviderServer creates a new TLSProviderServer on the selected interface and port.
+// Setting iface and / or port to an empty string will make the server fall back to
+// the "any" interface and port 443 respectively.
+func NewTLSProviderServer(iface, port string) *TLSProviderServer {
+	return &TLSProviderServer{iface: iface, port: port}
+}
+
+// Present makes the keyAuth available as a cert
+func (s *TLSProviderServer) Present(domain, token, keyAuth string) error {
+	if s.port == "" {
+		s.port = "443"
+	}
+
+	cert, err := TLSSNI01ChallengeCert(keyAuth)
+	if err != nil {
+		return err
+	}
+
+	tlsConf := new(tls.Config)
+	tlsConf.Certificates = []tls.Certificate{cert}
+
+	s.listener, err = tls.Listen("tcp", net.JoinHostPort(s.iface, s.port), tlsConf)
+	if err != nil {
+		return fmt.Errorf("Could not start HTTPS server for challenge -> %v", err)
+	}
+
+	s.done = make(chan bool)
+	go func() {
+		http.Serve(s.listener, nil)
+		s.done <- true
+	}()
+	return nil
+}
+
+// CleanUp closes the HTTP server.
+func (s *TLSProviderServer) CleanUp(domain, token, keyAuth string) error {
+	if s.listener == nil {
+		return nil
+	}
+	s.listener.Close()
+	<-s.done
+	return nil
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/tls_sni_challenge_test.go

@@ -0,0 +1,65 @@
+package acme
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/tls"
+	"encoding/hex"
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestTLSSNIChallenge(t *testing.T) {
+	privKey, _ := rsa.GenerateKey(rand.Reader, 512)
+	j := &jws{privKey: privKey}
+	clientChallenge := challenge{Type: TLSSNI01, Token: "tlssni1"}
+	mockValidate := func(_ *jws, _, _ string, chlng challenge) error {
+		conn, err := tls.Dial("tcp", "localhost:23457", &tls.Config{
+			InsecureSkipVerify: true,
+		})
+		if err != nil {
+			t.Errorf("Expected to connect to challenge server without an error. %s", err.Error())
+		}
+
+		// Expect the server to only return one certificate
+		connState := conn.ConnectionState()
+		if count := len(connState.PeerCertificates); count != 1 {
+			t.Errorf("Expected the challenge server to return exactly one certificate but got %d", count)
+		}
+
+		remoteCert := connState.PeerCertificates[0]
+		if count := len(remoteCert.DNSNames); count != 1 {
+			t.Errorf("Expected the challenge certificate to have exactly one DNSNames entry but had %d", count)
+		}
+
+		zBytes := sha256.Sum256([]byte(chlng.KeyAuthorization))
+		z := hex.EncodeToString(zBytes[:sha256.Size])
+		domain := fmt.Sprintf("%s.%s.acme.invalid", z[:32], z[32:])
+
+		if remoteCert.DNSNames[0] != domain {
+			t.Errorf("Expected the challenge certificate DNSName to match %s but was %s", domain, remoteCert.DNSNames[0])
+		}
+
+		return nil
+	}
+	solver := &tlsSNIChallenge{jws: j, validate: mockValidate, provider: &TLSProviderServer{port: "23457"}}
+
+	if err := solver.Solve(clientChallenge, "localhost:23457"); err != nil {
+		t.Errorf("Solve error: got %v, want nil", err)
+	}
+}
+
+func TestTLSSNIChallengeInvalidPort(t *testing.T) {
+	privKey, _ := rsa.GenerateKey(rand.Reader, 128)
+	j := &jws{privKey: privKey}
+	clientChallenge := challenge{Type: TLSSNI01, Token: "tlssni2"}
+	solver := &tlsSNIChallenge{jws: j, validate: stubValidate, provider: &TLSProviderServer{port: "123456"}}
+
+	if err := solver.Solve(clientChallenge, "localhost:123456"); err == nil {
+		t.Errorf("Solve error: got %v, want error", err)
+	} else if want := "invalid port 123456"; !strings.HasSuffix(err.Error(), want) {
+		t.Errorf("Solve error: got %q, want suffix %q", err.Error(), want)
+	}
+}

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/utils.go

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

vendor/github.com/rsc/letsencrypt/vendor/github.com/xenolf/lego/acme/utils_test.go

@@ -0,0 +1,26 @@
+package acme
+
+import (
+	"testing"
+	"time"
+)
+
+func TestWaitForTimeout(t *testing.T) {
+	c := make(chan error)
+	go func() {
+		err := WaitFor(3*time.Second, 1*time.Second, func() (bool, error) {
+			return false, nil
+		})
+		c <- err
+	}()
+
+	timeout := time.After(4 * time.Second)
+	select {
+	case <-timeout:
+		t.Fatal("timeout exceeded")
+	case err := <-c:
+		if err == nil {
+			t.Errorf("expected timeout error; got %v", err)
+		}
+	}
+}

vendor/github.com/rsc/letsencrypt/vendor/vendor.json

@@ -0,0 +1,31 @@
+{
+	"comment": "",
+	"ignore": "",
+	"package": [
+		{
+			"checksumSHA1": "CHmdoMriAboKW2nHYSXo0yBizaE=",
+			"path": "github.com/xenolf/lego/acme",
+			"revision": "ca19a90028e242e878585941c2a27c8f3b3efc25",
+			"revisionTime": "2016-03-28T16:28:34Z"
+		},
+		{
+			"checksumSHA1": "jrheBzltbBE1frmNXQiu911T7dE=",
+			"path": "gopkg.in/square/go-jose.v1",
+			"revision": "40d457b439244b546f023d056628e5184136899b",
+			"revisionTime": "2016-03-29T20:33:11Z"
+		},
+		{
+			"checksumSHA1": "fX4KSC9E1oX9yRx20Zjb3rVJHn4=",
+			"path": "gopkg.in/square/go-jose.v1/cipher",
+			"revision": "40d457b439244b546f023d056628e5184136899b",
+			"revisionTime": "2016-03-29T20:33:11Z"
+		},
+		{
+			"checksumSHA1": "NxdXsIcLGuuX654ygsaOhoLsg6s=",
+			"path": "gopkg.in/square/go-jose.v1/json",
+			"revision": "40d457b439244b546f023d056628e5184136899b",
+			"revisionTime": "2016-03-29T20:33:11Z"
+		}
+	],
+	"rootPath": "rsc.io/letsencrypt"
+}