pages-server/certificates.go

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package main
import (
"bytes"
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
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"crypto/tls"
"crypto/x509"
"encoding/gob"
"encoding/json"
"errors"
"github.com/OrlovEvgeny/go-mcache"
"github.com/akrylysov/pogreb/fs"
"github.com/go-acme/lego/v4/certificate"
"github.com/go-acme/lego/v4/challenge"
"github.com/go-acme/lego/v4/challenge/resolver"
"github.com/go-acme/lego/v4/challenge/tlsalpn01"
"github.com/go-acme/lego/v4/providers/dns"
"io/ioutil"
"log"
"os"
"strings"
"sync"
"time"
"github.com/akrylysov/pogreb"
"github.com/reugn/equalizer"
"github.com/go-acme/lego/v4/certcrypto"
"github.com/go-acme/lego/v4/lego"
"github.com/go-acme/lego/v4/registration"
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)
// tlsConfig contains the configuration for generating, serving and cleaning up Let's Encrypt certificates.
var tlsConfig = &tls.Config{
// check DNS name & get certificate from Let's Encrypt
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GetCertificate: func(info *tls.ClientHelloInfo) (*tls.Certificate, error) {
sni := strings.ToLower(strings.TrimSpace(info.ServerName))
sniBytes := []byte(sni)
if len(sni) < 1 {
return nil, errors.New("missing sni")
}
if info.SupportedProtos != nil {
for _, proto := range info.SupportedProtos {
if proto == tlsalpn01.ACMETLS1Protocol {
challenge, ok := challengeCache.Get(sni)
if !ok {
return nil, errors.New("no challenge for this domain")
}
cert, err := tlsalpn01.ChallengeCert(sni, challenge.(string))
if err != nil {
return nil, err
}
return cert, nil
}
}
}
targetOwner := ""
if bytes.HasSuffix(sniBytes, MainDomainSuffix) || bytes.Equal(sniBytes, MainDomainSuffix[1:]) {
// deliver default certificate for the main domain (*.codeberg.page)
sniBytes = MainDomainSuffix
sni = string(sniBytes)
} else {
var targetRepo, targetBranch string
targetOwner, targetRepo, targetBranch = getTargetFromDNS(sni)
if targetOwner == "" {
// DNS not set up, return main certificate to redirect to the docs
sniBytes = MainDomainSuffix
sni = string(sniBytes)
} else {
_, _ = targetRepo, targetBranch
_, valid := checkCanonicalDomain(targetOwner, targetRepo, targetBranch, sni)
if !valid {
sniBytes = MainDomainSuffix
sni = string(sniBytes)
}
}
}
if tlsCertificate, ok := keyCache.Get(sni); ok {
// we can use an existing certificate object
return tlsCertificate.(*tls.Certificate), nil
}
var tlsCertificate tls.Certificate
var err error
var ok bool
if tlsCertificate, ok = retrieveCertFromDB(sniBytes); !ok {
// request a new certificate
if bytes.Equal(sniBytes, MainDomainSuffix) {
return nil, errors.New("won't request certificate for main domain, something really bad has happened")
}
tlsCertificate, err = obtainCert(acmeClient, []string{sni}, nil, targetOwner)
if err != nil {
return nil, err
}
}
err = keyCache.Set(sni, &tlsCertificate, 15 * time.Minute)
if err != nil {
panic(err)
}
return &tlsCertificate, nil
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},
PreferServerCipherSuites: true,
NextProtos: []string{
"http/1.1",
tlsalpn01.ACMETLS1Protocol,
},
// generated 2021-07-13, Mozilla Guideline v5.6, Go 1.14.4, intermediate configuration
// https://ssl-config.mozilla.org/#server=go&version=1.14.4&config=intermediate&guideline=5.6
MinVersion: tls.VersionTLS12,
CipherSuites: []uint16{
tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
},
}
var keyCache = mcache.New()
var keyDatabase *pogreb.DB
func CheckUserLimit(user string) (error) {
userLimit, ok := acmeClientCertificateLimitPerUser[user]
if !ok {
// Each Codeberg user can only add 10 new domains per day.
userLimit = equalizer.NewTokenBucket(10, time.Hour * 24)
acmeClientCertificateLimitPerUser[user] = userLimit
}
if !userLimit.Ask() {
return errors.New("rate limit exceeded: 10 certificates per user per 24 hours")
}
return nil
}
var myAcmeAccount AcmeAccount
var myAcmeConfig *lego.Config
type AcmeAccount struct {
Email string
Registration *registration.Resource
Key crypto.PrivateKey `json:"-"`
KeyPEM string `json:"Key"`
}
func (u *AcmeAccount) GetEmail() string {
return u.Email
}
func (u AcmeAccount) GetRegistration() *registration.Resource {
return u.Registration
}
func (u *AcmeAccount) GetPrivateKey() crypto.PrivateKey {
return u.Key
}
func newAcmeClient(configureChallenge func(*resolver.SolverManager) error) *lego.Client {
acmeClient, err := lego.NewClient(myAcmeConfig)
if err != nil {
panic(err)
}
err = configureChallenge(acmeClient.Challenge)
if err != nil {
panic(err)
}
return acmeClient
}
var acmeClient, mainDomainAcmeClient *lego.Client
var acmeClientCertificateLimitPerUser = map[string]*equalizer.TokenBucket{}
// rate limit is 300 / 3 hours, we want 200 / 2 hours but to refill more often, so that's 25 new domains every 15 minutes
// TODO: when this is used a lot, we probably have to think of a somewhat better solution?
var acmeClientOrderLimit = equalizer.NewTokenBucket(25, 15 * time.Minute)
// rate limit is 20 / second, we want 10 / second
var acmeClientRequestLimit = equalizer.NewTokenBucket(10, 1 * time.Second)
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var challengeCache = mcache.New()
type AcmeTLSChallengeProvider struct{}
var _ challenge.Provider = AcmeTLSChallengeProvider{}
func (a AcmeTLSChallengeProvider) Present(domain, _, keyAuth string) error {
return challengeCache.Set(domain, keyAuth, 1*time.Hour)
}
func (a AcmeTLSChallengeProvider) CleanUp(domain, _, _ string) error {
challengeCache.Remove(domain)
return nil
}
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type AcmeHTTPChallengeProvider struct{}
var _ challenge.Provider = AcmeHTTPChallengeProvider{}
func (a AcmeHTTPChallengeProvider) Present(domain, token, keyAuth string) error {
return challengeCache.Set(domain + "/" + token, keyAuth, 1*time.Hour)
}
func (a AcmeHTTPChallengeProvider) CleanUp(domain, token, _ string) error {
challengeCache.Remove(domain + "/" + token)
return nil
}
func retrieveCertFromDB(sni []byte) (tls.Certificate, bool) {
// parse certificate from database
resBytes, err := keyDatabase.Get(sni)
if err != nil {
// key database is not working
panic(err)
}
if resBytes == nil {
return tls.Certificate{}, false
}
resGob := bytes.NewBuffer(resBytes)
resDec := gob.NewDecoder(resGob)
res := &certificate.Resource{}
err = resDec.Decode(res)
if err != nil {
panic(err)
}
tlsCertificate, err := tls.X509KeyPair(res.Certificate, res.PrivateKey)
if err != nil {
panic(err)
}
if !bytes.Equal(sni, MainDomainSuffix) {
tlsCertificate.Leaf, err = x509.ParseCertificate(tlsCertificate.Certificate[0])
if err != nil {
panic(err)
}
// renew certificates 7 days before they expire
if !tlsCertificate.Leaf.NotAfter.After(time.Now().Add(-7 * 24 * time.Hour)) {
go (func() {
tlsCertificate, err = obtainCert(acmeClient, []string{string(sni)}, res, "")
if err != nil {
log.Printf("Couldn't renew certificate for %s: %s", sni, err)
}
})()
}
}
return tlsCertificate, true
}
var obtainLocks = sync.Map{}
func obtainCert(acmeClient *lego.Client, domains []string, renew *certificate.Resource, user string) (tls.Certificate, error) {
name := strings.TrimPrefix(domains[0], "*")
if os.Getenv("DNS_PROVIDER") == "" && len(domains[0]) > 0 && domains[0][0] == '*' {
domains = domains[1:]
}
// lock to avoid simultaneous requests
_, working := obtainLocks.LoadOrStore(name, struct{}{})
if working {
for working {
time.Sleep(100 * time.Millisecond)
_, working = obtainLocks.Load(name)
}
cert, ok := retrieveCertFromDB([]byte(name))
if !ok {
return tls.Certificate{}, errors.New("certificate failed in synchronous request")
}
return cert, nil
}
defer obtainLocks.Delete(name)
// request actual cert
var res *certificate.Resource
var err error
if renew != nil {
if os.Getenv("ACME_USE_RATE_LIMITS") != "false" {
acmeClientRequestLimit.Take()
}
log.Printf("Renewing certificate for %v", domains)
res, err = acmeClient.Certificate.Renew(*renew, true, false, "")
} else {
if user != "" {
if err := CheckUserLimit(user); err != nil {
return tls.Certificate{}, err
}
}
if os.Getenv("ACME_USE_RATE_LIMITS") != "false" {
acmeClientOrderLimit.Take()
acmeClientRequestLimit.Take()
}
log.Printf("Requesting new certificate for %v", domains)
res, err = acmeClient.Certificate.Obtain(certificate.ObtainRequest{
Domains: domains,
Bundle: true,
MustStaple: false,
})
}
if err != nil {
log.Printf("Couldn't obtain certificate for %v: %s", domains, err)
return tls.Certificate{}, err
}
log.Printf("Obtained certificate for %v", domains)
var resGob bytes.Buffer
resEnc := gob.NewEncoder(&resGob)
err = resEnc.Encode(res)
if err != nil {
panic(err)
}
err = keyDatabase.Put([]byte(name), resGob.Bytes())
if err != nil {
_ = keyDatabase.Delete([]byte(name + "/key"))
obtainLocks.Delete(name)
panic(err)
}
tlsCertificate, err := tls.X509KeyPair(res.Certificate, res.PrivateKey)
if err != nil {
return tls.Certificate{}, err
}
return tlsCertificate, nil
}
func setupCertificates() {
var err error
keyDatabase, err = pogreb.Open("key-database.pogreb", &pogreb.Options{
BackgroundSyncInterval: 30 * time.Second,
BackgroundCompactionInterval: 6 * time.Hour,
FileSystem: fs.OSMMap,
})
if err != nil {
panic(err)
}
if os.Getenv("ACME_ACCEPT_TERMS") != "true" || (os.Getenv("DNS_PROVIDER") == "" && os.Getenv("ACME_API") != "https://acme.mock.directory") {
panic(errors.New("you must set ACME_ACCEPT_TERMS and DNS_PROVIDER, unless ACME_API is set to https://acme.mock.directory"))
}
if account, err := ioutil.ReadFile("acme-account.json"); err == nil {
err = json.Unmarshal(account, &myAcmeAccount)
if err != nil {
panic(err)
}
myAcmeAccount.Key, err = certcrypto.ParsePEMPrivateKey([]byte(myAcmeAccount.KeyPEM))
if err != nil {
panic(err)
}
myAcmeConfig = lego.NewConfig(&myAcmeAccount)
myAcmeConfig.CADirURL = envOr("ACME_API", "https://acme-v02.api.letsencrypt.org/directory")
myAcmeConfig.Certificate.KeyType = certcrypto.RSA2048
newAcmeClient(func(manager *resolver.SolverManager) error { return nil })
} else if os.IsNotExist(err) {
privateKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
if err != nil {
panic(err)
}
myAcmeAccount = AcmeAccount{
Email: envOr("ACME_EMAIL", "noreply@example.email"),
Key: privateKey,
KeyPEM: string(certcrypto.PEMEncode(privateKey)),
}
myAcmeConfig = lego.NewConfig(&myAcmeAccount)
myAcmeConfig.CADirURL = envOr("ACME_API", "https://acme-v02.api.letsencrypt.org/directory")
myAcmeConfig.Certificate.KeyType = certcrypto.RSA2048
tempClient := newAcmeClient(func(manager *resolver.SolverManager) error { return nil })
// accept terms & log in to EAB
if os.Getenv("ACME_EAB_KID") == "" || os.Getenv("ACME_EAB_HMAC") == "" {
reg, err := tempClient.Registration.Register(registration.RegisterOptions{TermsOfServiceAgreed: os.Getenv("ACME_ACCEPT_TERMS") == "true"})
if err != nil {
panic(err)
}
myAcmeAccount.Registration = reg
} else {
reg, err := tempClient.Registration.RegisterWithExternalAccountBinding(registration.RegisterEABOptions{
TermsOfServiceAgreed: os.Getenv("ACME_ACCEPT_TERMS") == "true",
Kid: os.Getenv("ACME_EAB_KID"),
HmacEncoded: os.Getenv("ACME_EAB_HMAC"),
})
if err != nil {
panic(err)
}
myAcmeAccount.Registration = reg
}
acmeAccountJson, err := json.Marshal(myAcmeAccount)
if err != nil {
panic(err)
}
err = ioutil.WriteFile("acme-account.json", acmeAccountJson, 0600)
if err != nil {
panic(err)
}
} else {
panic(err)
}
acmeClient = newAcmeClient(func(challenge *resolver.SolverManager) error {
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err = challenge.SetTLSALPN01Provider(AcmeTLSChallengeProvider{})
if err != nil {
return err
}
if os.Getenv("ENABLE_HTTP_SERVER") == "true" {
return challenge.SetHTTP01Provider(AcmeHTTPChallengeProvider{})
}
return err
})
mainDomainAcmeClient = newAcmeClient(func(challenge *resolver.SolverManager) error {
if os.Getenv("DNS_PROVIDER") == "" {
// using mock server, don't use wildcard certs
return challenge.SetTLSALPN01Provider(AcmeTLSChallengeProvider{})
}
provider, err := dns.NewDNSChallengeProviderByName(os.Getenv("DNS_PROVIDER"))
if err != nil {
return err
}
return challenge.SetDNS01Provider(provider)
})
resBytes, err := keyDatabase.Get(MainDomainSuffix)
if err != nil {
// key database is not working
panic(err)
} else if resBytes == nil {
_, err = obtainCert(mainDomainAcmeClient, []string{"*" + string(MainDomainSuffix), string(MainDomainSuffix[1:])}, nil, "")
if err != nil {
log.Fatalf("Couldn't renew certificate for *%s: %s", MainDomainSuffix, err)
}
}
go (func() {
for {
err := keyDatabase.Sync()
if err != nil {
log.Printf("Syncinc key database failed: %s", err)
}
time.Sleep(5 * time.Minute)
}
})()
go (func() {
for {
// clean up expired certs
now := time.Now()
expiredCertCount := 0
keyDatabaseIterator := keyDatabase.Items()
key, resBytes, err := keyDatabaseIterator.Next()
for err == nil {
if !bytes.Equal(key, MainDomainSuffix) {
resGob := bytes.NewBuffer(resBytes)
resDec := gob.NewDecoder(resGob)
res := &certificate.Resource{}
err = resDec.Decode(res)
if err != nil {
panic(err)
}
tlsCertificates, err := certcrypto.ParsePEMBundle(res.Certificate)
if err != nil || !tlsCertificates[0].NotAfter.After(now) {
err := keyDatabase.Delete(key)
if err != nil {
log.Printf("Deleting expired certificate for %s failed: %s", string(key), err)
} else {
expiredCertCount++
}
}
}
key, resBytes, err = keyDatabaseIterator.Next()
}
log.Printf("Removed %d expired certificates from the database", expiredCertCount)
// compact the database
result, err := keyDatabase.Compact()
if err != nil {
log.Printf("Compacting key database failed: %s", err)
} else {
log.Printf("Compacted key database (%+v)", result)
}
// update main cert
resBytes, err = keyDatabase.Get(MainDomainSuffix)
if err != nil {
// key database is not working
panic(err)
}
resGob := bytes.NewBuffer(resBytes)
resDec := gob.NewDecoder(resGob)
res := &certificate.Resource{}
err = resDec.Decode(res)
if err != nil {
panic(err)
}
tlsCertificates, err := certcrypto.ParsePEMBundle(res.Certificate)
// renew main certificate 30 days before it expires
if !tlsCertificates[0].NotAfter.After(time.Now().Add(-30 * 24 * time.Hour)) {
go (func() {
_, err = obtainCert(mainDomainAcmeClient, []string{"*" + string(MainDomainSuffix), string(MainDomainSuffix[1:])}, res, "")
if err != nil {
log.Printf("Couldn't renew certificate for *%s: %s", MainDomainSuffix, err)
}
})()
}
time.Sleep(12 * time.Hour)
}
})()
}