traefik/acme/acme.go
2016-08-22 13:33:49 +02:00

504 lines
14 KiB
Go

package acme
import (
"crypto"
"crypto/rand"
"crypto/rsa"
"crypto/tls"
"crypto/x509"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
fmtlog "log"
"os"
"reflect"
"strings"
"sync"
"time"
log "github.com/Sirupsen/logrus"
"github.com/containous/traefik/safe"
"github.com/xenolf/lego/acme"
)
// Account is used to store lets encrypt registration info
type Account struct {
Email string
Registration *acme.RegistrationResource
PrivateKey []byte
DomainsCertificate DomainsCertificates
}
// GetEmail returns email
func (a Account) GetEmail() string {
return a.Email
}
// GetRegistration returns lets encrypt registration resource
func (a Account) GetRegistration() *acme.RegistrationResource {
return a.Registration
}
// GetPrivateKey returns private key
func (a Account) GetPrivateKey() crypto.PrivateKey {
if privateKey, err := x509.ParsePKCS1PrivateKey(a.PrivateKey); err == nil {
return privateKey
}
log.Errorf("Cannot unmarshall private key %+v", a.PrivateKey)
return nil
}
// Certificate is used to store certificate info
type Certificate struct {
Domain string
CertURL string
CertStableURL string
PrivateKey []byte
Certificate []byte
}
// DomainsCertificates stores a certificate for multiple domains
type DomainsCertificates struct {
Certs []*DomainsCertificate
lock *sync.RWMutex
}
func (dc *DomainsCertificates) init() error {
if dc.lock == nil {
dc.lock = &sync.RWMutex{}
}
dc.lock.Lock()
defer dc.lock.Unlock()
for _, domainsCertificate := range dc.Certs {
tlsCert, err := tls.X509KeyPair(domainsCertificate.Certificate.Certificate, domainsCertificate.Certificate.PrivateKey)
if err != nil {
return err
}
domainsCertificate.tlsCert = &tlsCert
}
return nil
}
func (dc *DomainsCertificates) renewCertificates(acmeCert *Certificate, domain Domain) error {
dc.lock.Lock()
defer dc.lock.Unlock()
for _, domainsCertificate := range dc.Certs {
if reflect.DeepEqual(domain, domainsCertificate.Domains) {
tlsCert, err := tls.X509KeyPair(acmeCert.Certificate, acmeCert.PrivateKey)
if err != nil {
return err
}
domainsCertificate.Certificate = acmeCert
domainsCertificate.tlsCert = &tlsCert
return nil
}
}
return errors.New("Certificate to renew not found for domain " + domain.Main)
}
func (dc *DomainsCertificates) addCertificateForDomains(acmeCert *Certificate, domain Domain) (*DomainsCertificate, error) {
dc.lock.Lock()
defer dc.lock.Unlock()
tlsCert, err := tls.X509KeyPair(acmeCert.Certificate, acmeCert.PrivateKey)
if err != nil {
return nil, err
}
cert := DomainsCertificate{Domains: domain, Certificate: acmeCert, tlsCert: &tlsCert}
dc.Certs = append(dc.Certs, &cert)
return &cert, nil
}
func (dc *DomainsCertificates) getCertificateForDomain(domainToFind string) (*DomainsCertificate, bool) {
dc.lock.RLock()
defer dc.lock.RUnlock()
for _, domainsCertificate := range dc.Certs {
domains := []string{}
domains = append(domains, domainsCertificate.Domains.Main)
domains = append(domains, domainsCertificate.Domains.SANs...)
for _, domain := range domains {
if domain == domainToFind {
return domainsCertificate, true
}
}
}
return nil, false
}
func (dc *DomainsCertificates) exists(domainToFind Domain) (*DomainsCertificate, bool) {
dc.lock.RLock()
defer dc.lock.RUnlock()
for _, domainsCertificate := range dc.Certs {
if reflect.DeepEqual(domainToFind, domainsCertificate.Domains) {
return domainsCertificate, true
}
}
return nil, false
}
// DomainsCertificate contains a certificate for multiple domains
type DomainsCertificate struct {
Domains Domain
Certificate *Certificate
tlsCert *tls.Certificate
}
func (dc *DomainsCertificate) needRenew() bool {
for _, c := range dc.tlsCert.Certificate {
crt, err := x509.ParseCertificate(c)
if err != nil {
// If there's an error, we assume the cert is broken, and needs update
return true
}
// <= 7 days left, renew certificate
if crt.NotAfter.Before(time.Now().Add(time.Duration(24 * 7 * time.Hour))) {
return true
}
}
return false
}
// ACME allows to connect to lets encrypt and retrieve certs
type ACME struct {
Email string `description:"Email address used for registration"`
Domains []Domain `description:"SANs (alternative domains) to each main domain using format: --acme.domains='main.com,san1.com,san2.com' --acme.domains='main.net,san1.net,san2.net'"`
StorageFile string `description:"File used for certificates storage."`
OnDemand bool `description:"Enable on demand certificate. This will request a certificate from Let's Encrypt during the first TLS handshake for a hostname that does not yet have a certificate."`
OnHostRule bool `description:"Enable certificate generation on frontends Host rules."`
CAServer string `description:"CA server to use."`
EntryPoint string `description:"Entrypoint to proxy acme challenge to."`
storageLock sync.RWMutex
client *acme.Client
account *Account
}
//Domains parse []Domain
type Domains []Domain
//Set []Domain
func (ds *Domains) Set(str string) error {
fargs := func(c rune) bool {
return c == ',' || c == ';'
}
// get function
slice := strings.FieldsFunc(str, fargs)
if len(slice) < 1 {
return fmt.Errorf("Parse error ACME.Domain. Imposible to parse %s", str)
}
d := Domain{
Main: slice[0],
SANs: []string{},
}
if len(slice) > 1 {
d.SANs = slice[1:]
}
*ds = append(*ds, d)
return nil
}
//Get []Domain
func (ds *Domains) Get() interface{} { return []Domain(*ds) }
//String returns []Domain in string
func (ds *Domains) String() string { return fmt.Sprintf("%+v", *ds) }
//SetValue sets []Domain into the parser
func (ds *Domains) SetValue(val interface{}) {
*ds = Domains(val.([]Domain))
}
// Domain holds a domain name with SANs
type Domain struct {
Main string
SANs []string
}
// CreateConfig creates a tls.config from using ACME configuration
func (a *ACME) CreateConfig(tlsConfig *tls.Config, CheckOnDemandDomain func(domain string) bool) error {
acme.Logger = fmtlog.New(ioutil.Discard, "", 0)
if len(a.StorageFile) == 0 {
return errors.New("Empty StorageFile, please provide a filename for certs storage")
}
log.Debugf("Generating default certificate...")
if len(tlsConfig.Certificates) == 0 {
// no certificates in TLS config, so we add a default one
cert, err := generateDefaultCertificate()
if err != nil {
return err
}
tlsConfig.Certificates = append(tlsConfig.Certificates, *cert)
}
var needRegister bool
var err error
// if certificates in storage, load them
if fileInfo, err := os.Stat(a.StorageFile); err == nil && fileInfo.Size() != 0 {
log.Infof("Loading ACME certificates...")
// load account
a.account, err = a.loadAccount(a)
if err != nil {
return err
}
} else {
log.Infof("Generating ACME Account...")
// Create a user. New accounts need an email and private key to start
privateKey, err := rsa.GenerateKey(rand.Reader, 4096)
if err != nil {
return err
}
a.account = &Account{
Email: a.Email,
PrivateKey: x509.MarshalPKCS1PrivateKey(privateKey),
}
a.account.DomainsCertificate = DomainsCertificates{Certs: []*DomainsCertificate{}, lock: &sync.RWMutex{}}
needRegister = true
}
a.client, err = a.buildACMEClient()
if err != nil {
return err
}
a.client.ExcludeChallenges([]acme.Challenge{acme.HTTP01, acme.DNS01})
wrapperChallengeProvider := newWrapperChallengeProvider()
a.client.SetChallengeProvider(acme.TLSSNI01, wrapperChallengeProvider)
if needRegister {
// New users will need to register; be sure to save it
reg, err := a.client.Register()
if err != nil {
return err
}
a.account.Registration = reg
}
// The client has a URL to the current Let's Encrypt Subscriber
// Agreement. The user will need to agree to it.
err = a.client.AgreeToTOS()
if err != nil {
return err
}
safe.Go(func() {
a.retrieveCertificates(a.client)
if err := a.renewCertificates(a.client); err != nil {
log.Errorf("Error renewing ACME certificate %+v: %s", a.account, err.Error())
}
})
tlsConfig.GetCertificate = func(clientHello *tls.ClientHelloInfo) (*tls.Certificate, error) {
if challengeCert, ok := wrapperChallengeProvider.getCertificate(clientHello.ServerName); ok {
return challengeCert, nil
}
if domainCert, ok := a.account.DomainsCertificate.getCertificateForDomain(clientHello.ServerName); ok {
return domainCert.tlsCert, nil
}
if a.OnDemand {
if CheckOnDemandDomain != nil && !CheckOnDemandDomain(clientHello.ServerName) {
return nil, nil
}
return a.loadCertificateOnDemand(clientHello)
}
return nil, nil
}
ticker := time.NewTicker(24 * time.Hour)
safe.Go(func() {
for {
select {
case <-ticker.C:
if err := a.renewCertificates(a.client); err != nil {
log.Errorf("Error renewing ACME certificate %+v: %s", a.account, err.Error())
}
}
}
})
return nil
}
func (a *ACME) retrieveCertificates(client *acme.Client) {
log.Infof("Retrieving ACME certificates...")
for _, domain := range a.Domains {
// check if cert isn't already loaded
if _, exists := a.account.DomainsCertificate.exists(domain); !exists {
domains := []string{}
domains = append(domains, domain.Main)
domains = append(domains, domain.SANs...)
certificateResource, err := a.getDomainsCertificates(client, domains)
if err != nil {
log.Errorf("Error getting ACME certificate for domain %s: %s", domains, err.Error())
continue
}
_, err = a.account.DomainsCertificate.addCertificateForDomains(certificateResource, domain)
if err != nil {
log.Errorf("Error adding ACME certificate for domain %s: %s", domains, err.Error())
continue
}
if err = a.saveAccount(); err != nil {
log.Errorf("Error Saving ACME account %+v: %s", a.account, err.Error())
continue
}
}
}
log.Infof("Retrieved ACME certificates")
}
func (a *ACME) renewCertificates(client *acme.Client) error {
log.Debugf("Testing certificate renew...")
for _, certificateResource := range a.account.DomainsCertificate.Certs {
if certificateResource.needRenew() {
log.Debugf("Renewing certificate %+v", certificateResource.Domains)
renewedCert, err := client.RenewCertificate(acme.CertificateResource{
Domain: certificateResource.Certificate.Domain,
CertURL: certificateResource.Certificate.CertURL,
CertStableURL: certificateResource.Certificate.CertStableURL,
PrivateKey: certificateResource.Certificate.PrivateKey,
Certificate: certificateResource.Certificate.Certificate,
}, true)
if err != nil {
log.Errorf("Error renewing certificate: %v", err)
continue
}
log.Debugf("Renewed certificate %+v", certificateResource.Domains)
renewedACMECert := &Certificate{
Domain: renewedCert.Domain,
CertURL: renewedCert.CertURL,
CertStableURL: renewedCert.CertStableURL,
PrivateKey: renewedCert.PrivateKey,
Certificate: renewedCert.Certificate,
}
err = a.account.DomainsCertificate.renewCertificates(renewedACMECert, certificateResource.Domains)
if err != nil {
log.Errorf("Error renewing certificate: %v", err)
continue
}
if err = a.saveAccount(); err != nil {
log.Errorf("Error saving ACME account: %v", err)
continue
}
}
}
return nil
}
func (a *ACME) buildACMEClient() (*acme.Client, error) {
caServer := "https://acme-v01.api.letsencrypt.org/directory"
if len(a.CAServer) > 0 {
caServer = a.CAServer
}
client, err := acme.NewClient(caServer, a.account, acme.RSA4096)
if err != nil {
return nil, err
}
return client, nil
}
func (a *ACME) loadCertificateOnDemand(clientHello *tls.ClientHelloInfo) (*tls.Certificate, error) {
if certificateResource, ok := a.account.DomainsCertificate.getCertificateForDomain(clientHello.ServerName); ok {
return certificateResource.tlsCert, nil
}
certificate, err := a.getDomainsCertificates(a.client, []string{clientHello.ServerName})
if err != nil {
return nil, err
}
log.Debugf("Got certificate on demand for domain %s", clientHello.ServerName)
cert, err := a.account.DomainsCertificate.addCertificateForDomains(certificate, Domain{Main: clientHello.ServerName})
if err != nil {
return nil, err
}
if err = a.saveAccount(); err != nil {
return nil, err
}
return cert.tlsCert, nil
}
// LoadCertificateForDomains loads certificates from ACME for given domains
func (a *ACME) LoadCertificateForDomains(domains []string) {
safe.Go(func() {
var domain Domain
if len(domains) == 0 {
// no domain
return
} else if len(domains) > 1 {
domain = Domain{Main: domains[0], SANs: domains[1:]}
} else {
domain = Domain{Main: domains[0]}
}
if _, exists := a.account.DomainsCertificate.exists(domain); exists {
// domain already exists
return
}
certificate, err := a.getDomainsCertificates(a.client, domains)
if err != nil {
log.Errorf("Error getting ACME certificates %+v : %v", domains, err)
return
}
log.Debugf("Got certificate for domains %+v", domains)
_, err = a.account.DomainsCertificate.addCertificateForDomains(certificate, domain)
if err != nil {
log.Errorf("Error adding ACME certificates %+v : %v", domains, err)
return
}
if err = a.saveAccount(); err != nil {
log.Errorf("Error Saving ACME account %+v: %v", a.account, err)
return
}
})
}
func (a *ACME) loadAccount(acmeConfig *ACME) (*Account, error) {
a.storageLock.RLock()
defer a.storageLock.RUnlock()
Account := Account{
DomainsCertificate: DomainsCertificates{},
}
file, err := ioutil.ReadFile(acmeConfig.StorageFile)
if err != nil {
return nil, err
}
if err := json.Unmarshal(file, &Account); err != nil {
return nil, err
}
err = Account.DomainsCertificate.init()
if err != nil {
return nil, err
}
log.Infof("Loaded ACME config from storage %s", acmeConfig.StorageFile)
return &Account, nil
}
func (a *ACME) saveAccount() error {
a.storageLock.Lock()
defer a.storageLock.Unlock()
// write account to file
data, err := json.MarshalIndent(a.account, "", " ")
if err != nil {
return err
}
return ioutil.WriteFile(a.StorageFile, data, 0600)
}
func (a *ACME) getDomainsCertificates(client *acme.Client, domains []string) (*Certificate, error) {
log.Debugf("Loading ACME certificates %s...", domains)
bundle := true
certificate, failures := client.ObtainCertificate(domains, bundle, nil)
if len(failures) > 0 {
log.Error(failures)
return nil, fmt.Errorf("Cannot obtain certificates %s+v", failures)
}
log.Debugf("Loaded ACME certificates %s", domains)
return &Certificate{
Domain: certificate.Domain,
CertURL: certificate.CertURL,
CertStableURL: certificate.CertStableURL,
PrivateKey: certificate.PrivateKey,
Certificate: certificate.Certificate,
}, nil
}