.gitlab-ci.yml

+include:
+  - "https://git.autistici.org/pipelines/debian/raw/master/common.yml"
+  - "https://git.autistici.org/pipelines/images/test/golang/raw/master/ci.yml"

README.md

@@ -3,3 +3,34 @@ acmeserver
 
 Runs a daemon to manage a set of SSL certificates using the ACME protocol.
 
+There are many similar tools, why another one? Well we need a few
+unique features:
+
+* custom output code for certificates and private keys, so we can
+  write them to [replds](https://git.autistici.org/ai3/replds) and
+  have them replicated to all front-ends;
+* support for our DNS setup for *dns-01* challenges, by sending RFC
+  2136 updates to all DNS servers in parallel.
+
+For the rest it's a fairly common ACME automation tool, it supports
+the *http-01* and *dns-01* challenges (no *tls-sni-01* because the
+tool is meant to be run behind a HTTPS proxy so it can't directly
+control the serving certificates).
+
+Since this is a particularly critical piece of software, a few extra
+cautions are necessary in its development:
+
+* do not implement any ACME-specific code but use a well-maintained
+  library instead
+  (like [golang.org/x/crypto/acme](https://golang.org/x/crypto/acme))
+* try to be robust against ACME high-level protocol changes by keeping
+  this tool replaceable with *certbot* and a bunch of shell
+  scripts. In particular we can do this by:
+  * keeping a directory structure for the output that's compatible
+    with certbot
+  * having a way to independently push content to replds (which we do,
+    by way of the *replds* command itself)
+    
+  So the advantage of *acmeserver* becomes just the integration
+  between the various components in a single package / binary (and
+  monitoring, etc).

acme.go

@@ -13,23 +13,31 @@ import (
 	"io/ioutil"
 	"log"
 	"net/http"
-	"path/filepath"
-	"strings"
-	"sync"
 
 	"golang.org/x/crypto/acme"
 )
 
-// ACME handles the certificate creation/renewal workflow using acme
-// http-01 challenges. It serves validation tokens under the
-// /.well-known/acme-challenge path when used as an HTTP handler.
+const (
+	http01Challenge = "http-01"
+	dns01Challenge  = "dns-01"
+)
+
+type validator interface {
+	Fulfill(context.Context, *acme.Client, string, *acme.Challenge) (func(), error)
+}
+
+// ACME is a simple wrapper for an acme.Client that handles the
+// certificate creation/renewal workflow using http-01 or dns-01
+// challenges.
 type ACME struct {
 	email          string
 	accountKeyPath string
+	directoryURL   string
 	client         *acme.Client
 
-	mx         sync.Mutex
-	httpTokens map[string][]byte
+	handler              http.Handler
+	validators           map[string]validator
+	defaultChallengeType string
 }
 
 // NewACME returns a new ACME object with the provided config.
@@ -37,15 +45,50 @@ func NewACME(config *Config) (*ACME, error) {
 	if config.Email == "" {
 		return nil, errors.New("configuration parameter 'email' is unset")
 	}
+	if config.AccountKeyPath == "" {
+		return nil, errors.New("configuration parameter 'account_key_path' is unset")
+	}
+
+	var h http.Handler
+	v := make(map[string]validator)
+	if config.HTTP.Enabled {
+		httpv := newHTTPValidator()
+		h = httpv
+		v[http01Challenge] = httpv
+	}
+	if config.DNS.Enabled {
+		dnsv, err := newDNSValidator(config)
+		if err != nil {
+			return nil, err
+		}
+		v[dns01Challenge] = dnsv
+	}
+
+	defaultChalType := config.DefaultChallengeType
+	if defaultChalType == "" {
+		defaultChalType = http01Challenge
+	}
+	if _, ok := v[defaultChalType]; !ok {
+		return nil, fmt.Errorf("the default challenge type '%s' is not configured", defaultChalType)
+	}
+
+	directoryURL := config.DirectoryURL
+	if directoryURL == "" {
+		directoryURL = acme.LetsEncryptURL
+	}
 
 	return &ACME{
-		email:          config.Email,
-		accountKeyPath: filepath.Join(config.Dir, "account.key"),
-		httpTokens:     make(map[string][]byte),
+		email:                config.Email,
+		accountKeyPath:       config.AccountKeyPath,
+		directoryURL:         directoryURL,
+		handler:              h,
+		validators:           v,
+		defaultChallengeType: defaultChalType,
 	}, nil
 }
 
-func (a *ACME) accountKey(ctx context.Context) (crypto.Signer, error) {
+// Return the account key, possibly initializing it if it does not exist.
+func (a *ACME) accountKey() (crypto.Signer, error) {
 	if key, err := parsePrivateKeyFromFile(a.accountKeyPath); err == nil {
 		return key, err
 	}
@@ -66,15 +109,18 @@ func (a *ACME) accountKey(ctx context.Context) (crypto.Signer, error) {
 	return eckey, err
 }
 
+// Return a new acme.Client, possibly initializing the account key if
+// it does not exist yet. The Client is created on the first call and
+// cached thereafter.
 func (a *ACME) acmeClient(ctx context.Context) (*acme.Client, error) {
 	if a.client != nil {
 		return a.client, nil
 	}
 
 	client := &acme.Client{
-		DirectoryURL: acme.LetsEncryptURL,
+		DirectoryURL: a.directoryURL,
 	}
-	key, err := a.accountKey(ctx)
+	key, err := a.accountKey()
 	if err != nil {
 		return nil, err
 	}
@@ -82,131 +128,135 @@ func (a *ACME) acmeClient(ctx context.Context) (*acme.Client, error) {
 	ac := &acme.Account{
 		Contact: []string{"mailto:" + a.email},
 	}
+
+	// Register the account (accept TOS) if necessary. If the
+	// account is already registered we get a StatusConflict,
+	// which we can ignore.
 	_, err = client.Register(ctx, ac, func(_ string) bool { return true })
-	if ae, ok := err.(*acme.Error); err == nil || ok && ae.StatusCode == http.StatusConflict {
+	if ae, ok := err.(*acme.Error); err == nil || err == acme.ErrAccountAlreadyExists || (ok && ae.StatusCode == http.StatusConflict) {
 		a.client = client
 		err = nil
 	}
+
+	// Fetch account info and display it.
+	if acct, err := client.GetReg(ctx, ""); err == nil {
+		log.Printf("ACME account %s", acct.URI)
+	}
+
 	return a.client, err
 }
 
 // GetCertificate returns a certificate chain (and the parsed leaf
 // cert), given a private key and a list of domains. The first domain
 // will be the subject CN, the others will be added as subjectAltNames.
-func (a *ACME) GetCertificate(ctx context.Context, key crypto.Signer, domains []string) (der [][]byte, leaf *x509.Certificate, err error) {
+func (a *ACME) GetCertificate(ctx context.Context, key crypto.Signer, c *certConfig) (der [][]byte, leaf *x509.Certificate, err error) {
 	client, err := a.acmeClient(ctx)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	if err = a.verifyAll(ctx, client, domains); err != nil {
+	o, err := a.verifyAll(ctx, client, c)
+	if err != nil {
 		return nil, nil, err
 	}
 
-	csr, err := certRequest(key, domains)
+	csr, err := certRequest(key, c.Names)
 	if err != nil {
 		return nil, nil, err
 	}
-	der, _, err = client.CreateCert(ctx, csr, 0, true)
+	der, _, err = client.CreateOrderCert(ctx, o.FinalizeURL, csr, true)
 	if err != nil {
 		return nil, nil, err
 	}
-	leaf, err = validCert(domains, der, key)
+	leaf, err = validCert(c.Names, der, key)
 	if err != nil {
 		return nil, nil, err
 	}
 	return der, leaf, nil
 }
 
-func (a *ACME) verifyAll(ctx context.Context, client *acme.Client, domains []string) error {
-	for _, domain := range domains {
-		if err := a.verify(ctx, client, domain); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func (a *ACME) verify(ctx context.Context, client *acme.Client, domain string) error {
-	authz, err := client.Authorize(ctx, domain)
+func (a *ACME) verifyAll(ctx context.Context, client *acme.Client, c *certConfig) (*acme.Order, error) {
+	// Make an authorization request to the ACME server, and
+	// verify that it returns a valid response with challenges.
+	o, err := client.AuthorizeOrder(ctx, acme.DomainIDs(c.Names...))
 	if err != nil {
-		return err
+		return nil, fmt.Errorf("AuthorizeOrder failed: %v", err)
 	}
 
-	switch authz.Status {
-	case acme.StatusValid:
-		return nil // already authorized
-	case acme.StatusInvalid:
-		return fmt.Errorf("invalid authorization %q", authz.URI)
+	switch o.Status {
+	case acme.StatusReady:
+		return o, nil // already authorized
+	case acme.StatusPending:
+	default:
+		return nil, fmt.Errorf("invalid new order status %q", o.Status)
 	}
 
-	chal := pickChallenge("http-01", authz.Challenges)
-	if chal == nil {
-		return fmt.Errorf("unable to authorize %q", domain)
-	}
-	cleanup, err := a.fulfill(ctx, client, chal)
-	if err != nil {
-		return err
-	}
-	defer cleanup()
+	for _, zurl := range o.AuthzURLs {
+		z, err := client.GetAuthorization(ctx, zurl)
+		if err != nil {
+			return nil, fmt.Errorf("GetAuthorization(%s) failed: %v", zurl, err)
+		}
+		if z.Status != acme.StatusPending {
+			continue
+		}
+		// Pick a challenge that matches our preferences and the
+		// available validators. The validator fulfills the challenge,
+		// and returns a cleanup function that we're going to call
+		// before we return. All steps are sequential and idempotent.
+		chal := a.pickChallenge(z.Challenges, c)
+		if chal == nil {
+			return nil, fmt.Errorf("unable to authorize %q", c.Names)
+		}
 
-	if _, err = client.Accept(ctx, chal); err != nil {
-		return err
-	}
-	_, err = client.WaitAuthorization(ctx, authz.URI)
-	return err
-}
+		v, ok := a.validators[chal.Type]
+		if !ok {
+			return nil, fmt.Errorf("challenge type '%s' is not available", chal.Type)
+		}
 
-func (a *ACME) fulfill(ctx context.Context, client *acme.Client, chal *acme.Challenge) (cleanup func(), err error) {
-	if chal.Type != "http-01" {
-		return nil, errors.New("unsupported challenge type")
-	}
+		log.Printf("attempting fulfillment for %q (identifier: %+v)", c.Names, z.Identifier)
+		for _, domain := range c.Names {
+			cleanup, err := v.Fulfill(ctx, client, domain, chal)
+			if err != nil {
+				return nil, fmt.Errorf("fulfillment failed: %v", err)
+			}
+			defer cleanup()
+		}
 
-	resp, err := client.HTTP01ChallengeResponse(chal.Token)
-	if err != nil {
-		return nil, err
+		if _, err := client.Accept(ctx, chal); err != nil {
+			return nil, fmt.Errorf("challenge accept failed: %v", err)
+		}
+		if _, err := client.WaitAuthorization(ctx, z.URI); err != nil {
+			return nil, fmt.Errorf("WaitAuthorization(%s) failed: %v", z.URI, err)
+		}
 	}
-	p := client.HTTP01ChallengePath(chal.Token)
-	a.putHTTPToken(ctx, p, resp)
-	return func() { go a.deleteHTTPToken(p) }, nil
-}
-
-func (a *ACME) httpToken(ctx context.Context, tokenPath string) ([]byte, error) {
-	a.mx.Lock()
-	defer a.mx.Unlock()
 
-	if v, ok := a.httpTokens[tokenPath]; ok {
-		return v, nil
+	// Authorizations are satisfied, wait for the CA
+	// to update the order status.
+	if _, err = client.WaitOrder(ctx, o.URI); err != nil {
+		return nil, err
 	}
-	return nil, errors.New("token not found")
-}
-
-func (a *ACME) putHTTPToken(ctx context.Context, tokenPath, val string) {
-	a.mx.Lock()
-	a.httpTokens[tokenPath] = []byte(val)
-	a.mx.Unlock()
-}
-
-func (a *ACME) deleteHTTPToken(tokenPath string) {
-	a.mx.Lock()
-	delete(a.httpTokens, tokenPath)
-	a.mx.Unlock()
+	return o, nil
 }
 
-func (a *ACME) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if !strings.HasPrefix(r.URL.Path, "/.well-known/acme-challenge/") {
-		http.NotFound(w, r)
-		return
+// Pick a challenge with the right type from the Challenge response
+// returned by the ACME server. We have a pretty specific idea of the
+// challenge type we want (either the default, or the ChallengeType
+// specified in the cert config), so we just search for that one.
+func (a *ACME) pickChallenge(chal []*acme.Challenge, c *certConfig) *acme.Challenge {
+	ctype := a.defaultChallengeType
+	if c.ChallengeType != "" {
+		ctype = c.ChallengeType
 	}
-
-	a.mx.Lock()
-	defer a.mx.Unlock()
-
-	data, err := a.httpToken(r.Context(), r.URL.Path)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusNotFound)
-		return
+	for _, ch := range chal {
+		if ch.Type == ctype {
+			return ch
+		}
 	}
+	return nil
+}
 
-	w.Write(data)
+// Handler returns the http.Handler that is used to satisfy the
+// http-01 validation requests.
+func (a *ACME) Handler() http.Handler {
+	return a.handler
 }

cmd/acmeserver/acmeserver.go

@@ -3,35 +3,38 @@ package main
 import (
 	"context"
 	"flag"
-	"io/ioutil"
 	"log"
+	"net/http"
 	"os"
 	"os/signal"
 	"syscall"
 
-	"git.autistici.org/ai3/acmeserver"
 	"git.autistici.org/ai3/go-common/serverutil"
-	"gopkg.in/yaml.v2"
+	"git.autistici.org/ai3/tools/acmeserver"
+	"gopkg.in/yaml.v3"
 )
 
 var (
 	addr       = flag.String("addr", ":2780", "tcp `address` to listen on")
-	configFile = flag.String("config", "/etc/acmeserver/config.yml", "configuration `file`")
+	configFile = flag.String("config", "/etc/acme/config.yml", "configuration `file`")
 )
 
+// Config ties together the acmeserver Config and the standard
+// serverutil HTTP server configuration.
 type Config struct {
-	ACME   *acmeserver.Config       `yaml:",inline"`
+	ACME   acmeserver.Config        `yaml:",inline"`
 	Server *serverutil.ServerConfig `yaml:"http_server"`
 }
 
 func loadConfig(path string) (*Config, error) {
 	// Read YAML config.
-	data, err := ioutil.ReadFile(path)
+	f, err := os.Open(path)
 	if err != nil {
 		return nil, err
 	}
+	defer f.Close()
 	var config Config
-	if err := yaml.Unmarshal(data, &config); err != nil {
+	if err := yaml.NewDecoder(f).Decode(&config); err != nil {
 		return nil, err
 	}
 	return &config, nil
@@ -46,22 +49,41 @@ func main() {
 		log.Fatal(err)
 	}
 
-	acme, err := acmeserver.NewACME(config.ACME)
-	if err != nil {
-		log.Fatal(err)
+	var h http.Handler
+	var cg acmeserver.CertGenerator
+	if !config.ACME.Testing {
+		acme, err := acmeserver.NewACME(&config.ACME) // nolint: vetshadow
+		if err != nil {
+			log.Fatal(err)
+		}
+		cg = acme
+		h = acme.Handler()
+
+	} else {
+		// When testing=true there's no content to serve over
+		// HTTP. Metrics and other debug pages are added
+		// automatically by the serverutil package.
+		cg = acmeserver.NewSelfSignedCertGenerator()
+		h = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			http.NotFound(w, r)
+		})
 	}
 
-	m, err := acmeserver.NewManager(config.ACME, acme)
+	m, err := acmeserver.NewManager(&config.ACME, cg)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	// Start the acmeserver.Manager, and set up a SIGHUP handler to reload its config.
-	if err := m.Start(context.Background()); err != nil {
+	// Start the acmeserver.Manager in the background. The
+	// serverutil package installs SIGTERM handlers that stop the
+	// HTTP server, so when it terminates we also kill the context
+	// attached to the Manager.
+	ctx, cancel := context.WithCancel(context.Background())
+	if err := m.Start(ctx); err != nil {
 		log.Fatal(err)
 	}
-	defer m.Stop()
 
+	// Set up a SIGHUP handler to reload the configuration.
 	hupCh := make(chan os.Signal, 1)
 	go func() {
 		for {
@@ -71,7 +93,10 @@ func main() {
 	}()
 	signal.Notify(hupCh, syscall.SIGHUP)
 
-	if err := serverutil.Serve(acme, config.Server, *addr); err != nil {
+	if err := serverutil.Serve(h, config.Server, *addr); err != nil {
 		log.Fatal(err)
 	}
+
+	cancel()
+	m.Wait()
 }

config.go

 package acmeserver
 
 import (
-	"io/ioutil"
+	"errors"
+	"fmt"
 	"log"
+	"os"
 	"path/filepath"
 
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 
 	"git.autistici.org/ai3/go-common/clientutil"
 )
 
 // Config holds the configuration for an acmeserver instance.
+//
+// The reason for supporting multiple config_dirs is to allow
+// integration with third-party automation systems: in some cases,
+// automation tools need control of an entire directory in order to
+// safely delete entries that no longer exist.
+//
+// nolint: maligned
 type Config struct {
-	Addr string `yaml:"addr"`
+	Testing              bool   `yaml:"testing"`
+	DirectoryURL         string `yaml:"directory_url"`
+	DefaultChallengeType string `yaml:"default_challenge"`
+	UseRSA               bool   `yaml:"use_rsa"`
+	RenewalDays          int    `yaml:"renewal_days"`
 
-	Email  string                    `yaml:"email"`
-	UseRSA bool                      `yaml:"use_rsa"`
-	Dir    string                    `yaml:"cert_dir"`
-	ReplDS *clientutil.BackendConfig `yaml:"replds"`
+	AccountKeyPath string `yaml:"account_key_path"`
+	Email          string `yaml:"email"`
+
+	Dirs []string `yaml:"config_dirs"`
+
+	Output struct {
+		Path   string                    `yaml:"path"`
+		ReplDS *clientutil.BackendConfig `yaml:"replds"`
+	} `yaml:"output"`
+
+	HTTP struct {
+		Enabled bool `yaml:"enabled"`
+	} `yaml:"http"`
+
+	DNS struct {
+		Enabled       bool     `yaml:"enabled"`
+		Nameservers   []string `yaml:"nameservers"`
+		TSIGKeyName   string   `yaml:"tsig_key_name"`
+		TSIGKeyAlgo   string   `yaml:"tsig_key_algo"`
+		TSIGKeySecret string   `yaml:"tsig_key_secret"`
+	} `yaml:"dns"`
 }
 
-// Definition of a single certificate: the main CN, and optionally a
-// list of subjectAltName entries.
+// This is all the configuration we need to generate a certificate.
 type certConfig struct {
-	CN       string   `yaml:"cn"`
-	AltNames []string `yaml:"alt_names"`
+	// List of names for this certificate. The first one will be
+	// the certificate CN, all of them will be subjectAltNames.
+	Names []string `yaml:"names"`
+
+	// Challenge type to use for this domain. If empty, the
+	// defaults will be applied.
+	ChallengeType string `yaml:"challenge,omitempty"`
 }
 
-func decodeCertConfig(data []byte) ([][]string, error) {
-	var cc []certConfig
-	if err := yaml.Unmarshal(data, &cc); err != nil {
-		return nil, err
+func (c *certConfig) check() error {
+	if len(c.Names) == 0 {
+		return errors.New("empty names list")
 	}
-
-	var domains [][]string
-	for _, c := range cc {
-		d := []string{c.CN}
-		d = append(d, c.AltNames...)
-		domains = append(domains, d)
+	// We can't check here if the challenge type is actually
+	// configured or not, but at least we can report unknown /
+	// unsupported types as syntax errors.
+	switch c.ChallengeType {
+	case "", dns01Challenge, http01Challenge:
+	default:
+		return fmt.Errorf("unkown or unsupported challenge type '%s'", c.ChallengeType)
 	}
-	return domains, nil
+	return nil
 }
 
-func readCertConfig(path string) ([][]string, error) {
-	data, err := ioutil.ReadFile(path)
+func readCertConfigs(path string) ([]*certConfig, error) {
+	f, err := os.Open(path)
 	if err != nil {
 		return nil, err
 	}
-	return decodeCertConfig(data)
+	defer f.Close()
+	var cc []*certConfig
+	if err := yaml.NewDecoder(f).Decode(&cc); err != nil {
+		return nil, err
+	}
+	return cc, nil
 }
 
-func readCertConfigsFromDir(dir string) ([][]string, error) {
+func readCertConfigsFromDir(dir string, certs []*certConfig) ([]*certConfig, error) {
 	files, err := filepath.Glob(filepath.Join(dir, "*.yml"))
 	if err != nil {
 		return nil, err
 	}
-	var domains [][]string
 	for _, f := range files {
-		d, err := readCertConfig(f)
+		cc, err := readCertConfigs(f)
 		if err != nil {
 			log.Printf("error reading %s: %v", f, err)
 			continue
 		}
-		domains = append(domains, d...)
+		// Validate the cert configs, skip ones with errors.
+		for _, c := range cc {
+			if err := c.check(); err != nil {
+				log.Printf("configuration error in %s: %v", f, err)
+				continue
+			}
+			certs = append(certs, c)
+		}
+	}
+	return certs, nil
+}
+
+func readCertConfigsFromDirs(dirs []string) ([]*certConfig, error) {
+	var out []*certConfig
+	for _, dir := range dirs {
+		certs, err := readCertConfigsFromDir(dir, out)
+		if err != nil {
+			return nil, err
+		}
+		out = certs
 	}
-	return domains, nil
+	return out, nil
 }

debian/acmeserver.default

+ADDR=:5004

debian/acmeserver.service

+[Unit]
+Description=ACMEserver
+After=network.target
+
+[Service]
+User=acmeserver
+Group=acmeserver
+EnvironmentFile=-/etc/default/acmeserver
+ExecStart=/usr/bin/acmeserver --addr $ADDR
+ExecReload=/bin/kill -HUP $MAINPID
+Restart=always
+
+# Hardening
+NoNewPrivileges=yes
+PrivateTmp=yes
+PrivateDevices=yes
+ProtectHome=yes
+ProtectSystem=full
+ReadOnlyDirectories=/
+ReadWriteDirectories=/var/lib/acme
+CapabilityBoundingSet=CAP_NET_BIND_SERVICE
+
+[Install]
+WantedBy=multi-user.target
+

debian/changelog

+acmeserver (2.0) unstable; urgency=medium
+
+  * Initial Release.
+
+ -- Autistici/Inventati <debian@autistici.org>  Fri, 15 Jun 2018 09:23:40 +0000

debian/control

+Source: acmeserver
+Section: admin
+Priority: optional
+Maintainer: Autistici/Inventati <debian@autistici.org>
+Build-Depends: debhelper-compat (= 13), golang-any (>= 1.11), dh-golang
+Standards-Version: 3.9.6
+
+Package: acmeserver
+Architecture: any
+Depends: ${shlibs:Depends}, ${misc:Depends}
+Built-Using: ${misc:Built-Using}
+Description: ACME server
+ Automatically manages and renews public SSL certificates.

debian/copyright

+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: acmeserver
+Source: <https://git.autistici.org/ai3/tools/acmeserver>
+
+Files: *
+Copyright: 2018 Autistici/Inventati <info@autistici.org>
+License: GPL-3.0+
+
+License: GPL-3.0+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+ .
+ This package is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ .
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+ .
+ On Debian systems, the complete text of the GNU General
+ Public License version 3 can be found in "/usr/share/common-licenses/GPL-3".
+

debian/postinst

+#!/bin/sh
+
+set -e
+
+case "$1" in
+configure)
+    addgroup --system --quiet acmeserver
+    adduser --system --no-create-home --home /run/acmeserver \
+      --disabled-password --disabled-login \
+      --quiet --ingroup acmeserver acmeserver
+    ;;
+esac
+
+#DEBHELPER#
+
+exit 0

debian/rules

+#!/usr/bin/make -f
+
+export DH_GOPKG = git.autistici.org/ai3/tools/acmeserver
+export DH_GOLANG_EXCLUDES = vendor
+export DH_GOLANG_INSTALL_ALL := 1
+
+
+%:
+	dh $@ --with golang --buildsystem golang
+
+override_dh_auto_install:
+	dh_auto_install -- --no-source
+
+override_dh_installsystemd:
+	dh_installsystemd --no-enable
+
+override_dh_installsystemd:
+	dh_installsystemd --no-start

debian/source/format

+3.0 (native)

dns_challenge.go

+package acmeserver
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"strings"
+	"time"
+
+	"github.com/miekg/dns"
+	"golang.org/x/crypto/acme"
+	"golang.org/x/net/publicsuffix"
+)
+
+const (
+	rfc2136Timeout   = 600
+	tsigFudgeSeconds = 300
+)
+
+type dnsValidator struct {
+	nameservers []string
+	enableTSIG  bool
+	keyName     string
+	keyAlgo     string
+	keySecret   string
+}
+
+func newDNSValidator(config *Config) (*dnsValidator, error) {
+	if len(config.DNS.Nameservers) == 0 {
+		return nil, errors.New("no nameservers configured")
+	}
+
+	// Check that the TSIG parameters are consistent, if provided at all.
+	n := 0
+	if config.DNS.TSIGKeyName != "" {
+		n++
+	}
+	if config.DNS.TSIGKeyAlgo != "" {
+		n++
+	}
+	if config.DNS.TSIGKeySecret != "" {
+		n++
+	}
+	if n != 0 && n != 3 {
+		return nil, errors.New("either none or all of 'tsig_key_name', 'tsig_key_algo' and 'tsig_key_secret' must be set")
+	}
+
+	return &dnsValidator{
+		nameservers: config.DNS.Nameservers,
+		enableTSIG:  n > 0,
+		keyName:     dns.Fqdn(config.DNS.TSIGKeyName),
+		keyAlgo:     config.DNS.TSIGKeyAlgo,
+		keySecret:   config.DNS.TSIGKeySecret,
+	}, nil
+}
+
+func (d *dnsValidator) makeRR(fqdn, value string, ttl int) []dns.RR {
+	rr := new(dns.TXT)
+	rr.Hdr = dns.RR_Header{Name: fqdn, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: uint32(ttl)}
+	rr.Txt = []string{value}
+	return []dns.RR{rr}
+}
+
+func (d *dnsValidator) makeMsg(zone string, rrs []dns.RR, remove bool) *dns.Msg {
+	m := new(dns.Msg)
+	m.SetUpdate(zone)
+	if remove {
+		m.Remove(rrs)
+	} else {
+		m.RemoveRRset(rrs)
+		m.Insert(rrs)
+	}
+	if d.enableTSIG {
+		m.SetTsig(d.keyName, d.keyAlgo, tsigFudgeSeconds, time.Now().Unix())
+	}
+	return m
+}
+
+func (d *dnsValidator) client() *dns.Client {
+	c := new(dns.Client)
+	c.SingleInflight = true
+	if d.enableTSIG {
+		// TSIG authentication / msg signing.
+		c.TsigSecret = map[string]string{d.keyName: d.keySecret}
+	}
+	return c
+}
+
+func (d *dnsValidator) Fulfill(ctx context.Context, client *acme.Client, domain string, chal *acme.Challenge) (func(), error) {
+	domain = strings.TrimPrefix(domain, "*.")
+
+	zone, err := publicsuffix.EffectiveTLDPlusOne(domain)
+	if err != nil {
+		return nil, fmt.Errorf("could not determine effective tld: %w", err)
+	}
+
+	zone = dns.Fqdn(zone)
+	fqdn := dns.Fqdn("_acme-challenge." + domain)
+
+	value, err := client.DNS01ChallengeRecord(chal.Token)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := d.onAllNS(ctx, func(ns string) error {
+		return d.updateNS(ctx, ns, zone, fqdn, value, false)
+	}); err != nil {
+		return nil, err
+	}
+
+	return func() {
+		// nolint
+		d.onAllNS(ctx, func(ns string) error {
+			return d.updateNS(ctx, ns, zone, fqdn, value, true)
+		})
+	}, nil
+}
+
+func (d *dnsValidator) updateNS(ctx context.Context, ns, zone, fqdn, value string, remove bool) error {
+	log.Printf("updateNS(%s, %s, %s, %s, %v)", ns, zone, fqdn, value, remove)
+	rrs := d.makeRR(fqdn, value, rfc2136Timeout)
+	m := d.makeMsg(zone, rrs, remove)
+	c := d.client()
+
+	// Send the query
+	reply, _, err := c.Exchange(m, ns)
+	if err != nil {
+		return err
+	}
+	if reply != nil && reply.Rcode != dns.RcodeSuccess {
+		return fmt.Errorf("DNS server replied: %s", dns.RcodeToString[reply.Rcode])
+	}
+
+	return nil
+}
+
+// Run a function for each configured nameserver.
+func (d *dnsValidator) onAllNS(ctx context.Context, f func(string) error) error {
+	ch := make(chan error, len(d.nameservers))
+	defer close(ch)
+
+	for _, ns := range d.nameservers {
+		if !strings.Contains(ns, ":") {
+			ns += ":53"
+		}
+		go func(ns string) {
+			err := f(ns)
+			if err != nil {
+				log.Printf("error updating DNS server %s: %v", ns, err)
+			}
+			ch <- err
+		}(ns)
+	}
+
+	var ok bool
+	for i := 0; i < len(d.nameservers); i++ {
+		if err := <-ch; err == nil {
+			ok = true
+		}
+	}
+	if !ok {
+		return errors.New("all nameservers failed")
+	}
+	return nil
+}

go.mod

+module git.autistici.org/ai3/tools/acmeserver
+
+go 1.19
+
+require (
+	git.autistici.org/ai3/go-common v0.0.0-20230816213645-b3aa3fb514d6
+	git.autistici.org/ai3/tools/replds v0.0.0-20230923170339-b6e6e3cc032b
+	github.com/miekg/dns v1.1.50
+	github.com/prometheus/client_golang v1.12.2
+	golang.org/x/crypto v0.24.0
+	golang.org/x/net v0.26.0
+	gopkg.in/yaml.v3 v3.0.1
+)
+
+require (
+	github.com/NYTimes/gziphandler v1.1.1 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cenkalti/backoff/v4 v4.1.3 // indirect
+	github.com/cespare/xxhash/v2 v2.1.2 // indirect
+	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
+	github.com/felixge/httpsnoop v1.0.3 // indirect
+	github.com/go-logr/logr v1.2.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/openzipkin/zipkin-go v0.4.0 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.32.1 // indirect
+	github.com/prometheus/procfs v0.7.3 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.34.0 // indirect
+	go.opentelemetry.io/contrib/propagators/b3 v1.9.0 // indirect
+	go.opentelemetry.io/otel v1.10.0 // indirect
+	go.opentelemetry.io/otel/exporters/zipkin v1.9.0 // indirect
+	go.opentelemetry.io/otel/metric v0.31.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.10.0 // indirect
+	go.opentelemetry.io/otel/trace v1.10.0 // indirect
+	golang.org/x/mod v0.4.2 // indirect
+	golang.org/x/sync v0.3.0 // indirect
+	golang.org/x/sys v0.21.0 // indirect
+	golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	google.golang.org/protobuf v1.27.1 // indirect
+)

http_challenge.go

+package acmeserver
+
+import (
+	"context"
+	"net/http"
+	"sync"
+
+	"golang.org/x/crypto/acme"
+)
+
+// httpValidator can validate http-01 challenges. It serves
+// validation tokens under the /.well-known/acme-challenge path when
+// used as an HTTP handler.
+type httpValidator struct {
+	mx     sync.Mutex
+	tokens map[string][]byte
+}
+
+func newHTTPValidator() *httpValidator {
+	return &httpValidator{
+		tokens: make(map[string][]byte),
+	}
+}
+
+func (h *httpValidator) Fulfill(_ context.Context, client *acme.Client, _ string, chal *acme.Challenge) (func(), error) {
+	resp, err := client.HTTP01ChallengeResponse(chal.Token)
+	if err != nil {
+		return nil, err
+	}
+	path := client.HTTP01ChallengePath(chal.Token)
+
+	h.mx.Lock()
+	h.tokens[path] = []byte(resp)
+	h.mx.Unlock()
+
+	return func() {
+		go func() {
+			h.mx.Lock()
+			delete(h.tokens, path)
+			h.mx.Unlock()
+		}()
+	}, nil
+}
+
+func (h *httpValidator) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// No defer because it's not polite to Write() while holding the lock.
+	h.mx.Lock()
+	data, ok := h.tokens[r.URL.Path]
+	h.mx.Unlock()
+
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
+
+	// Not interested in errors writing the response.
+	w.Write(data) // nolint
+}

instrumentation.go

+package acmeserver
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	certExpirationTimes = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "cert_expiration_time",
+			Help: "Certificate expiration time.",
+		},
+		[]string{"cn"},
+	)
+	certOk = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "cert_ok",
+			Help: "Do we have a valid certificate.",
+		},
+		[]string{"cn"},
+	)
+	certRenewalCount = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "cert_renewal_total",
+			Help: "Total certificate renewal attempts.",
+		},
+		[]string{"cn"},
+	)
+	certRenewalErrorCount = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "cert_renewal_errors",
+			Help: "Errors while renewing certificates.",
+		},
+		[]string{"cn"},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(certExpirationTimes, certOk, certRenewalErrorCount)
+}
+
+func b2f(b bool) float64 {
+	if b {
+		return 1
+	}
+	return 0
+}

server.go → manager.go

@@ -11,24 +11,57 @@ import (
 	"crypto/x509/pkix"
 	"encoding/pem"
 	"errors"
-	"fmt"
 	"io"
 	"log"
-	"path/filepath"
+	"sync"
 	"time"
 
-	"git.autistici.org/ai3/go-common/clientutil"
-	"golang.org/x/crypto/acme"
+	"git.autistici.org/ai3/tools/replds"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
+var (
+	defaultRenewalDays = 21
+	updateInterval     = 1 * time.Minute
+)
+
+// certInfo represents what we know about the state of the certificate
+// at runtime.
 type certInfo struct {
-	domains       []string
+	config        *certConfig
 	retryDeadline time.Time
 
-	// A write-only attribute (not part of the logic) to indicate
-	// whether we think we have a valid certificate or not. Used
-	// for monitoring and debugging.
-	valid bool
+	// Write-only attributes (not part of the renewal logic) to
+	// indicate whether we think we have a valid certificate or
+	// not. Used for monitoring and debugging.
+	valid     bool
+	expiresAt time.Time
+}
+
+func (i *certInfo) cn() string {
+	return i.config.Names[0]
+}
+
+func (i *certInfo) setOk(cert *x509.Certificate, renewalDays int) {
+	i.retryDeadline = cert.NotAfter.AddDate(0, 0, -renewalDays)
+	i.expiresAt = cert.NotAfter
+	i.valid = true
+
+	l := prometheus.Labels{"cn": i.cn()}
+	certOk.With(l).Set(1)
+}
+
+func (i *certInfo) setErr() {
+	now := time.Now()
+	i.retryDeadline = now.Add(errorRetryTimeout)
+	i.valid = false
+	if !i.expiresAt.IsZero() {
+		i.valid = i.expiresAt.After(now)
+	}
+
+	l := prometheus.Labels{"cn": i.cn()}
+	certRenewalErrorCount.With(l).Inc()
+	certOk.With(l).Set(b2f(i.valid))
 }
 
 type certStorage interface {
@@ -36,53 +69,61 @@ type certStorage interface {
 	PutCert(string, [][]byte, crypto.Signer) error
 }
 
+// CertGenerator is an interface to something that can generate a new
+// certificate, given a list of domains and a private key. The ACME
+// type implements this interface.
 type CertGenerator interface {
-	GetCertificate(context.Context, crypto.Signer, []string) ([][]byte, *x509.Certificate, error)
+	GetCertificate(context.Context, crypto.Signer, *certConfig) ([][]byte, *x509.Certificate, error)
 }
 
-// Manager periodically renews certificates before they expire, and
-// responds to http-01 validation requests.
+// Manager periodically renews certificates before they expire.
 type Manager struct {
-	//email          string
-	//accountKeyPath string
-	configDir string
-	useRSA    bool
-	storage   certStorage
-	certs     []*certInfo
-	certGen   CertGenerator
-
-	configCh chan [][]string
-	stopCh   chan bool
+	configDirs  []string
+	useRSA      bool
+	storage     certStorage
+	certGen     CertGenerator
+	renewalDays int
+
+	configCh chan []*certConfig
 	doneCh   chan bool
+
+	mx    sync.Mutex
+	certs []*certInfo
 }
 
 // NewManager creates a new Manager with the given configuration.
 func NewManager(config *Config, certGen CertGenerator) (*Manager, error) {
 	// Validate the configuration.
-	if config.Dir == "" {
-		return nil, errors.New("configuration parameter 'cert_dir' is unset")
+	if len(config.Dirs) == 0 {
+		return nil, errors.New("configuration parameter 'config_dirs' is unset")
+	}
+	if config.Output.Path == "" {
+		return nil, errors.New("'output.path' is unset")
+	}
+	if config.RenewalDays <= 0 {
+		config.RenewalDays = defaultRenewalDays
 	}
 
 	m := &Manager{
-		useRSA:    config.UseRSA,
-		configDir: filepath.Join(config.Dir, "config"),
-		stopCh:    make(chan bool),
-		doneCh:    make(chan bool),
-		configCh:  make(chan [][]string, 1),
-		certGen:   certGen,
+		useRSA:      config.UseRSA,
+		configDirs:  config.Dirs,
+		doneCh:      make(chan bool),
+		configCh:    make(chan []*certConfig, 1),
+		certGen:     certGen,
+		renewalDays: config.RenewalDays,
 	}
 
-	ds := &dirStorage{root: filepath.Join(config.Dir, "certs")}
-	if config.ReplDS == nil {
+	ds := &dirStorage{root: config.Output.Path}
+	if config.Output.ReplDS == nil {
 		m.storage = ds
 	} else {
-		be, err := clientutil.NewBackend(config.ReplDS)
+		r, err := replds.NewPublicClient(config.Output.ReplDS)
 		if err != nil {
 			return nil, err
 		}
 		m.storage = &replStorage{
 			dirStorage: ds,
-			replClient: be,
+			replClient: r,
 		}
 	}
 
@@ -90,9 +131,10 @@ func NewManager(config *Config, certGen CertGenerator) (*Manager, error) {
 }
 
 // Start the renewal processes. Canceling the provided context will
-// cause background processing to stop.
+// cause background processing to stop, interrupting all running
+// updates.
 func (m *Manager) Start(ctx context.Context) error {
-	domains, err := readCertConfigsFromDir(m.configDir)
+	domains, err := readCertConfigsFromDirs(m.configDirs)
 	if err != nil {
 		return err
 	}
@@ -104,15 +146,14 @@ func (m *Manager) Start(ctx context.Context) error {
 	return nil
 }
 
-// Stop any pending operation and release all resources.
-func (m *Manager) Stop() {
-	close(m.stopCh)
+// Wait for the Manager to terminate once it has been canceled.
+func (m *Manager) Wait() {
 	<-m.doneCh
 }
 
 // Reload configuration.
 func (m *Manager) Reload() {
-	domains, err := readCertConfigsFromDir(m.configDir)
+	domains, err := readCertConfigsFromDirs(m.configDirs)
 	if err != nil {
 		log.Printf("error reading config: %v", err)
 		return
@@ -123,27 +164,37 @@ func (m *Manager) Reload() {
 
 var (
 	renewalTimeout    = 10 * time.Minute
-	errorRetryTimeout = 10 * time.Minute
+	errorRetryTimeout = 6 * time.Hour
 )
 
-func (m *Manager) updateAllCerts(ctx context.Context) {
-	for _, certInfo := range m.certs {
+func (m *Manager) updateAllCerts(ctx context.Context, certs []*certInfo) {
+	for _, certInfo := range certs {
 		if certInfo.retryDeadline.After(time.Now()) {
 			continue
 		}
+
+		// Abort the loop if our context is canceled.
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
+
+		certRenewalCount.With(prometheus.Labels{"cn": certInfo.cn()}).Inc()
 		uctx, cancel := context.WithTimeout(ctx, renewalTimeout)
-		err := m.updateCert(uctx, certInfo)
+		leaf, err := m.updateCert(uctx, certInfo)
 		cancel()
-		if err != nil {
-			log.Printf("error updating %s: %v", certInfo.domains[0], err)
-			// Retry in a little while.
-			certInfo.retryDeadline = time.Now().Add(errorRetryTimeout)
-			certInfo.valid = false
+		if err == nil {
+			log.Printf("successfully renewed %s", certInfo.cn())
+			certInfo.setOk(leaf, m.renewalDays)
+		} else {
+			log.Printf("error updating %s: %v", certInfo.cn(), err)
+			certInfo.setErr()
 		}
 	}
 }
 
-func (m *Manager) updateCert(ctx context.Context, certInfo *certInfo) error {
+func (m *Manager) updateCert(ctx context.Context, certInfo *certInfo) (*x509.Certificate, error) {
 	// Create a new private key.
 	var (
 		err error
@@ -155,49 +206,57 @@ func (m *Manager) updateCert(ctx context.Context, certInfo *certInfo) error {
 		key, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
 	}
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	der, leaf, err := m.certGen.GetCertificate(ctx, key, certInfo.domains)
+	der, leaf, err := m.certGen.GetCertificate(ctx, key, certInfo.config)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	if err := m.storage.PutCert(certInfo.domains[0], der, key); err != nil {
-		return err
+	if err := m.storage.PutCert(certInfo.cn(), der, key); err != nil {
+		return nil, err
 	}
 
-	certInfo.retryDeadline = renewalDeadline(leaf)
-	certInfo.valid = true
-
-	return nil
+	return leaf, nil
 }
 
 // Replace the current configuration.
-func (m *Manager) loadConfig(certDomains [][]string) {
-	var certs []*certInfo
-	for _, domains := range certDomains {
-		cn := domains[0]
+func (m *Manager) loadConfig(certs []*certConfig) []*certInfo {
+	var out []*certInfo
+	for _, c := range certs {
+		cn := c.Names[0]
 		certInfo := &certInfo{
-			domains: domains,
+			config: c,
 		}
 		pub, priv, err := m.storage.GetCert(cn)
 		if err != nil {
 			log.Printf("cert for %s is missing", cn)
 		} else {
 			// By calling validCert we catch things like subjectAltName changes.
-			leaf, err := validCert(domains, pub, priv)
+			leaf, err := validCert(c.Names, pub, priv)
 			if err == nil {
 				log.Printf("cert for %s loaded from storage", cn)
-				certInfo.retryDeadline = renewalDeadline(leaf)
-				certInfo.valid = true
+				certInfo.setOk(leaf, m.renewalDays)
 			} else {
 				log.Printf("cert for %s loaded from storage but parameters have changed", cn)
 			}
 		}
-		certs = append(certs, certInfo)
+		out = append(out, certInfo)
 	}
+	return out
+}
+
+func (m *Manager) getCerts() []*certInfo {
+	m.mx.Lock()
+	defer m.mx.Unlock()
+	return m.certs
+}
+
+func (m *Manager) setCerts(certs []*certInfo) {
+	m.mx.Lock()
 	m.certs = certs
+	m.mx.Unlock()
 }
 
 // This channel is used by the testing code to trigger an update,
@@ -205,27 +264,24 @@ func (m *Manager) loadConfig(certDomains [][]string) {
 var testUpdateCh = make(chan bool)
 
 func (m *Manager) loop(ctx context.Context) {
-	tick := time.NewTicker(5 * time.Minute)
-	for {
-		select {
-		case <-tick.C:
-			m.updateAllCerts(ctx)
-		case <-testUpdateCh:
-			m.updateAllCerts(ctx)
-		case certDomains := <-m.configCh:
-			m.loadConfig(certDomains)
-		case <-m.stopCh:
-			return
-		case <-ctx.Done():
-			return
+	reloadCh := make(chan interface{}, 1)
+	go func() {
+		for config := range m.configCh {
+			certs := m.loadConfig(config)
+			m.setCerts(certs)
+			reloadCh <- certs
 		}
-	}
-}
-
-var renewalDays = 15
+	}()
 
-func renewalDeadline(cert *x509.Certificate) time.Time {
-	return cert.NotAfter.AddDate(0, 0, -renewalDays)
+	runWithUpdates(
+		ctx,
+		func(ctx context.Context, value interface{}) {
+			certs := value.([]*certInfo)
+			m.updateAllCerts(ctx, certs)
+		},
+		reloadCh,
+		updateInterval,
+	)
 }
 
 func concatDER(der [][]byte) []byte {
@@ -242,60 +298,10 @@ func concatDER(der [][]byte) []byte {
 	return out
 }
 
-func validCert(domains []string, der [][]byte, key crypto.Signer) (leaf *x509.Certificate, err error) {
-	x509Cert, err := x509.ParseCertificates(concatDER(der))
-	if err != nil {
-		return nil, err
-	}
-	if len(x509Cert) == 0 {
-		return nil, errors.New("no public key found")
-	}
-	leaf = x509Cert[0]
-
-	// verify the leaf is not expired and matches the given domains
-	now := time.Now()
-	if now.Before(leaf.NotBefore) {
-		return nil, errors.New("certificate isn't valid yet")
-	}
-	if now.After(leaf.NotAfter) {
-		return nil, errors.New("certificate expired")
-	}
-	for _, domain := range domains {
-		if err := leaf.VerifyHostname(domain); err != nil {
-			return nil, fmt.Errorf("certificate does not match domain %q", domain)
-		}
-	}
-
-	// ensure the leaf corresponds to the private key
-	switch pub := leaf.PublicKey.(type) {
-	case *rsa.PublicKey:
-		prv, ok := key.(*rsa.PrivateKey)
-		if !ok {
-			return nil, errors.New("private key type does not match public key type")
-		}
-		if pub.N.Cmp(prv.N) != 0 {
-			return nil, errors.New("private key does not match public key")
-		}
-	case *ecdsa.PublicKey:
-		prv, ok := key.(*ecdsa.PrivateKey)
-		if !ok {
-			return nil, errors.New("private key type does not match public key type")
-		}
-		if pub.X.Cmp(prv.X) != 0 || pub.Y.Cmp(prv.Y) != 0 {
-			return nil, errors.New("private key does not match public key")
-		}
-	default:
-		return nil, errors.New("unsupported public key algorithm")
-	}
-	return leaf, nil
-}
-
 func certRequest(key crypto.Signer, domains []string) ([]byte, error) {
 	req := &x509.CertificateRequest{
-		Subject: pkix.Name{CommonName: domains[0]},
-	}
-	if len(domains) > 1 {
-		req.DNSNames = domains[1:]
+		Subject:  pkix.Name{CommonName: domains[0]},
+		DNSNames: domains,
 	}
 	return x509.CreateCertificateRequest(rand.Reader, req, key)
 }
@@ -329,12 +335,3 @@ func encodeECDSAKey(w io.Writer, key *ecdsa.PrivateKey) error {
 	pb := &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}
 	return pem.Encode(w, pb)
 }
-
-func pickChallenge(typ string, chal []*acme.Challenge) *acme.Challenge {
-	for _, c := range chal {
-		if c.Type == typ {
-			return c
-		}
-	}
-	return nil
-}

server_test.go → manager_test.go

@@ -3,77 +3,43 @@ package acmeserver
 import (
 	"context"
 	"crypto"
-	"crypto/ecdsa"
-	"crypto/rand"
-	"crypto/rsa"
 	"crypto/x509"
-	"crypto/x509/pkix"
+	"errors"
 	"io/ioutil"
-	"log"
-	"math/big"
 	"os"
 	"path/filepath"
 	"testing"
 	"time"
 )
 
-type fakeACME struct {
-}
-
-func (f *fakeACME) GetCertificate(_ context.Context, priv crypto.Signer, domains []string) ([][]byte, *x509.Certificate, error) {
-	notBefore := time.Now()
-	notAfter := notBefore.AddDate(1, 0, 0)
-
-	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
-	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	template := x509.Certificate{
-		SerialNumber: serialNumber,
-		Subject: pkix.Name{
-			CommonName: domains[0],
-		},
-		NotBefore: notBefore,
-		NotAfter:  notAfter,
+// A CertGenerator that is just very slow (and will return an error
+// in any case).
+type slowACME struct{}
 
-		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
-		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
-		BasicConstraintsValid: true,
+func (s *slowACME) GetCertificate(ctx context.Context, _ crypto.Signer, _ *certConfig) ([][]byte, *x509.Certificate, error) {
+	t := time.After(60 * time.Second)
+	select {
+	case <-t:
+		return nil, nil, errors.New("timed out")
+	case <-ctx.Done():
+		return nil, nil, ctx.Err()
 	}
-
-	if len(domains) > 1 {
-		template.DNSNames = domains[1:]
-	}
-
-	der, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	cert, err := x509.ParseCertificate(der)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	log.Printf("created certificate for %s", domains[0])
-
-	return [][]byte{der}, cert, nil
 }
 
-func publicKey(priv interface{}) interface{} {
-	switch k := priv.(type) {
-	case *rsa.PrivateKey:
-		return &k.PublicKey
-	case *ecdsa.PrivateKey:
-		return &k.PublicKey
-	default:
-		return nil
+func newTestConfig(dir string) *Config {
+	c := Config{
+		Dirs:           []string{filepath.Join(dir, "config")},
+		AccountKeyPath: filepath.Join(dir, "account.key"),
+		Email:          "test@example.com",
 	}
+	c.Output.Path = filepath.Join(dir, "certs")
+	return &c
 }
 
-func newTestManager(t testing.TB) (func(), *Manager) {
+// Create a new test function.
+// The first function returned is a cleanup callback.
+// The second function returned is the cancel callback.
+func newTestManager(t testing.TB, g CertGenerator) (func(), context.CancelFunc, *Manager) {
 	dir, err := ioutil.TempDir("", "")
 	if err != nil {
 		t.Fatal(err)
@@ -82,19 +48,17 @@ func newTestManager(t testing.TB) (func(), *Manager) {
 	os.Mkdir(filepath.Join(dir, "config"), 0700)
 	ioutil.WriteFile(
 		filepath.Join(dir, "config", "test.yml"),
-		[]byte("- { cn: example.com }\n"),
+		[]byte("- { names: [example.com] }\n"),
 		0644,
 	)
 
-	m, err := NewManager(&Config{
-		Dir:   dir,
-		Email: "test@example.com",
-	}, &fakeACME{})
+	m, err := NewManager(newTestConfig(dir), g)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	if err := m.Start(context.Background()); err != nil {
+	ctx, cancel := context.WithCancel(context.Background())
+	if err := m.Start(ctx); err != nil {
 		t.Fatal("Start:", err)
 	}
 
@@ -102,46 +66,55 @@ func newTestManager(t testing.TB) (func(), *Manager) {
 	time.Sleep(50 * time.Millisecond)
 
 	return func() {
-		m.Stop()
+		cancel()
+		m.Wait()
 		os.RemoveAll(dir)
-	}, m
+	}, cancel, m
 }
 
 func TestManager_Reload(t *testing.T) {
-	cleanup, m := newTestManager(t)
+	cleanup, _, m := newTestManager(t, NewSelfSignedCertGenerator())
 	defer cleanup()
 
 	// Data race: we read data owned by another goroutine!
-	if len(m.certs) < 1 {
+	certs := m.getCerts()
+	if len(certs) < 1 {
 		t.Fatal("configuration not loaded?")
 	}
-	if m.certs[0].domains[0] != "example.com" {
-		t.Fatalf("certs[0].domains[0] is %s, expected example.com", m.certs[0].domains[0])
+	if certs[0].cn() != "example.com" {
+		t.Fatalf("certs[0].cn() is %s, expected example.com", certs[0].cn())
 	}
 
 	// Try a reload, catch obvious errors.
 	m.Reload()
 	time.Sleep(50 * time.Millisecond)
+	certs = m.getCerts()
 
-	if len(m.certs) != 1 {
+	if len(certs) != 1 {
 		t.Fatalf("certs count is %d, expected 1", len(m.certs))
 	}
-	if m.certs[0].domains[0] != "example.com" {
-		t.Fatalf("certs[0].domains[0] is %s, expected example.com", m.certs[0].domains[0])
+	if certs[0].cn() != "example.com" {
+		t.Fatalf("certs[0].cn() is %s, expected example.com", certs[0].cn())
 	}
 }
 
 func TestManager_NewCert(t *testing.T) {
-	cleanup, m := newTestManager(t)
+	var oldUpdateInterval time.Duration
+	oldUpdateInterval, updateInterval = updateInterval, 50*time.Millisecond
+	defer func() {
+		updateInterval = oldUpdateInterval
+	}()
+
+	cleanup, _, m := newTestManager(t, NewSelfSignedCertGenerator())
 	defer cleanup()
 
 	now := time.Now()
-	ci := m.certs[0]
+	certs := m.getCerts()
+	ci := certs[0]
 	if ci.retryDeadline.After(now) {
 		t.Fatalf("retry deadline is in the future: %v", ci.retryDeadline)
 	}
 
-	testUpdateCh <- true
 	time.Sleep(100 * time.Millisecond)
 
 	// Verify that the retry/renewal timestamp is in the future.
@@ -156,11 +129,11 @@ func TestManager_NewCert(t *testing.T) {
 
 	// Verify that the credentials have successfully been written
 	// to storage.
-	p := filepath.Join(m.configDir, "../certs/example.com/cert.pem")
+	p := filepath.Join(m.configDirs[0], "../certs/example.com/cert.pem")
 	if _, err := os.Stat(p); err != nil {
 		t.Fatalf("file not created: %v", err)
 	}
-	p = filepath.Join(m.configDir, "../certs/example.com/private_key.pem")
+	p = filepath.Join(m.configDirs[0], "../certs/example.com/privkey.pem")
 	if _, err := os.Stat(p); err != nil {
 		t.Fatalf("file not created: %v", err)
 	}
@@ -170,8 +143,22 @@ func TestManager_NewCert(t *testing.T) {
 	m.Reload()
 	time.Sleep(50 * time.Millisecond)
 
-	ci = m.certs[0]
+	ci = m.getCerts()[0]
 	if !ci.valid {
 		t.Fatal("certificate is invalid after a reload")
 	}
 }
+
+func TestManager_CancelUpdate(t *testing.T) {
+	start := time.Now()
+	cleanup, cancel, m := newTestManager(t, &slowACME{})
+	defer cleanup()
+
+	time.Sleep(100 * time.Millisecond)
+	cancel()
+	m.Wait()
+	elapsed := time.Since(start)
+	if elapsed > 1*time.Second {
+		t.Fatalf("too much time elapsed (%fs), canceling didn't work?", elapsed.Seconds())
+	}
+}