package certificates import ( "context" "crypto/tls" "crypto/x509" "errors" "fmt" "strconv" "strings" "time" lru "github.com/hashicorp/golang-lru/v2" "github.com/go-acme/lego/v4/certcrypto" "github.com/go-acme/lego/v4/certificate" "github.com/go-acme/lego/v4/challenge/tlsalpn01" "github.com/go-acme/lego/v4/lego" "github.com/reugn/equalizer" "github.com/rs/zerolog/log" "codeberg.org/codeberg/pages/server/cache" "codeberg.org/codeberg/pages/server/database" dnsutils "codeberg.org/codeberg/pages/server/dns" "codeberg.org/codeberg/pages/server/gitea" "codeberg.org/codeberg/pages/server/upstream" ) var ErrUserRateLimitExceeded = errors.New("rate limit exceeded: 10 certificates per user per 24 hours") var keyCache *lru.Cache[string, tls.Certificate] // TLSConfig returns the configuration for generating, serving and cleaning up Let's Encrypt certificates. func TLSConfig(mainDomainSuffix string, giteaClient *gitea.Client, acmeClient *AcmeClient, firstDefaultBranch string, challengeCache, canonicalDomainCache cache.ICache, certDB database.CertDB, noDNS01 bool, rawDomain string, ) *tls.Config { return &tls.Config{ // check DNS name & get certificate from Let's Encrypt GetCertificate: func(info *tls.ClientHelloInfo) (*tls.Certificate, error) { domain := strings.ToLower(strings.TrimSpace(info.ServerName)) if len(domain) < 1 { return nil, errors.New("missing domain info via SNI (RFC 4366, Section 3.1)") } // https request init is actually a acme challenge if info.SupportedProtos != nil { for _, proto := range info.SupportedProtos { if proto != tlsalpn01.ACMETLS1Protocol { continue } log.Info().Msgf("Detect ACME-TLS1 challenge for '%s'", domain) challenge, ok := challengeCache.Get(domain) if !ok { return nil, errors.New("no challenge for this domain") } cert, err := tlsalpn01.ChallengeCert(domain, string(challenge)) if err != nil { return nil, err } return cert, nil } } targetOwner := "" mayObtainCert := true if strings.HasSuffix(domain, mainDomainSuffix) || strings.EqualFold(domain, mainDomainSuffix[1:]) { if noDNS01 { // Limit the domains allowed to request a certificate to pages-server domains // and domains for an existing user of org if !strings.EqualFold(domain, mainDomainSuffix[1:]) && !strings.EqualFold(domain, rawDomain) { targetOwner := strings.TrimSuffix(domain, mainDomainSuffix) owner_exist, err := giteaClient.GiteaCheckIfOwnerExists(targetOwner) mayObtainCert = owner_exist if err != nil { log.Error().Err(err).Msgf("Failed to check '%s' existence on the forge: %s", targetOwner, err) mayObtainCert = false } } } else { // deliver default certificate for the main domain (*.codeberg.page) domain = mainDomainSuffix } } else { var targetRepo, targetBranch string targetOwner, targetRepo, targetBranch = dnsutils.GetTargetFromDNS(domain, mainDomainSuffix, firstDefaultBranch) if targetOwner == "" { // DNS not set up, return main certificate to redirect to the docs domain = mainDomainSuffix } else { targetOpt := &upstream.Options{ TargetOwner: targetOwner, TargetRepo: targetRepo, TargetBranch: targetBranch, } _, valid := targetOpt.CheckCanonicalDomain(giteaClient, domain, mainDomainSuffix, canonicalDomainCache) if !valid { // We shouldn't obtain a certificate when we cannot check if the // repository has specified this domain in the `.domains` file. mayObtainCert = false } } } if keyCache == nil { var err error keyCache, err = lru.New[string, tls.Certificate](4096) if err != nil { panic(err) // This should only happen if 4096 < 0 at the time of writing, which should be reason enough to panic. } } if tlsCertificate, ok := keyCache.Get(domain); ok { // we can use an existing certificate object return &tlsCertificate, nil } var tlsCertificate *tls.Certificate var err error if tlsCertificate, err = acmeClient.retrieveCertFromDB(domain, mainDomainSuffix, false, certDB); err != nil { if !errors.Is(err, database.ErrNotFound) { return nil, err } // we could not find a cert in db, request a new certificate // first check if we are allowed to obtain a cert for this domain if strings.EqualFold(domain, mainDomainSuffix) { return nil, errors.New("won't request certificate for main domain, something really bad has happened") } if !mayObtainCert { return nil, fmt.Errorf("won't request certificate for %q", domain) } tlsCertificate, err = acmeClient.obtainCert(acmeClient.legoClient, []string{domain}, nil, targetOwner, false, mainDomainSuffix, certDB) if err != nil { return nil, err } } keyCache.Add(domain, *tlsCertificate) return tlsCertificate, nil }, NextProtos: []string{ "h2", "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, }, } } func (c *AcmeClient) checkUserLimit(user string) error { userLimit, ok := c.acmeClientCertificateLimitPerUser[user] if !ok { // Each user can only add 10 new domains per day. userLimit = equalizer.NewTokenBucket(10, time.Hour*24) c.acmeClientCertificateLimitPerUser[user] = userLimit } if !userLimit.Ask() { return fmt.Errorf("user '%s' error: %w", user, ErrUserRateLimitExceeded) } return nil } func (c *AcmeClient) retrieveCertFromDB(sni, mainDomainSuffix string, useDnsProvider bool, certDB database.CertDB) (*tls.Certificate, error) { // parse certificate from database res, err := certDB.Get(sni) if err != nil { return nil, err } else if res == nil { return nil, database.ErrNotFound } tlsCertificate, err := tls.X509KeyPair(res.Certificate, res.PrivateKey) if err != nil { return nil, err } // TODO: document & put into own function if !strings.EqualFold(sni, mainDomainSuffix) { tlsCertificate.Leaf, err = x509.ParseCertificate(tlsCertificate.Certificate[0]) if err != nil { return nil, fmt.Errorf("error parsing leaf tlsCert: %w", err) } // renew certificates 7 days before they expire if tlsCertificate.Leaf.NotAfter.Before(time.Now().Add(7 * 24 * time.Hour)) { // TODO: use ValidTill of custom cert struct if res.CSR != nil && len(res.CSR) > 0 { // CSR stores the time when the renewal shall be tried again nextTryUnix, err := strconv.ParseInt(string(res.CSR), 10, 64) if err == nil && time.Now().Before(time.Unix(nextTryUnix, 0)) { return &tlsCertificate, nil } } // TODO: make a queue ? go (func() { res.CSR = nil // acme client doesn't like CSR to be set if _, err := c.obtainCert(c.legoClient, []string{sni}, res, "", useDnsProvider, mainDomainSuffix, certDB); err != nil { log.Error().Msgf("Couldn't renew certificate for %s: %v", sni, err) } })() } } return &tlsCertificate, nil } func (c *AcmeClient) obtainCert(acmeClient *lego.Client, domains []string, renew *certificate.Resource, user string, useDnsProvider bool, mainDomainSuffix string, keyDatabase database.CertDB) (*tls.Certificate, error) { name := strings.TrimPrefix(domains[0], "*") // lock to avoid simultaneous requests _, working := c.obtainLocks.LoadOrStore(name, struct{}{}) if working { for working { time.Sleep(100 * time.Millisecond) _, working = c.obtainLocks.Load(name) } cert, err := c.retrieveCertFromDB(name, mainDomainSuffix, useDnsProvider, keyDatabase) if err != nil { return nil, fmt.Errorf("certificate failed in synchronous request: %w", err) } return cert, nil } defer c.obtainLocks.Delete(name) if acmeClient == nil { if useDnsProvider { return mockCert(domains[0], "DNS ACME client is not defined", mainDomainSuffix, keyDatabase) } else { return mockCert(domains[0], "ACME client uninitialized. This is a server error, please report!", mainDomainSuffix, keyDatabase) } } // request actual cert var res *certificate.Resource var err error if renew != nil && renew.CertURL != "" { if c.acmeUseRateLimits { c.acmeClientRequestLimit.Take() } log.Debug().Msgf("Renewing certificate for: %v", domains) res, err = acmeClient.Certificate.Renew(*renew, true, false, "") if err != nil { log.Error().Err(err).Msgf("Couldn't renew certificate for %v, trying to request a new one", domains) if c.acmeUseRateLimits { c.acmeClientFailLimit.Take() } res = nil } } if res == nil { if user != "" { if err := c.checkUserLimit(user); err != nil { return nil, err } } if c.acmeUseRateLimits { c.acmeClientOrderLimit.Take() c.acmeClientRequestLimit.Take() } log.Debug().Msgf("Re-requesting new certificate for %v", domains) res, err = acmeClient.Certificate.Obtain(certificate.ObtainRequest{ Domains: domains, Bundle: true, MustStaple: false, }) if c.acmeUseRateLimits && err != nil { c.acmeClientFailLimit.Take() } } if err != nil { log.Error().Err(err).Msgf("Couldn't obtain again a certificate or %v", domains) if renew != nil && renew.CertURL != "" { tlsCertificate, err := tls.X509KeyPair(renew.Certificate, renew.PrivateKey) if err != nil { mockC, err2 := mockCert(domains[0], err.Error(), mainDomainSuffix, keyDatabase) if err2 != nil { return nil, errors.Join(err, err2) } return mockC, err } leaf, err := leaf(&tlsCertificate) if err == nil && leaf.NotAfter.After(time.Now()) { // avoid sending a mock cert instead of a still valid cert, instead abuse CSR field to store time to try again at renew.CSR = []byte(strconv.FormatInt(time.Now().Add(6*time.Hour).Unix(), 10)) if err := keyDatabase.Put(name, renew); err != nil { mockC, err2 := mockCert(domains[0], err.Error(), mainDomainSuffix, keyDatabase) if err2 != nil { return nil, errors.Join(err, err2) } return mockC, err } return &tlsCertificate, nil } } return mockCert(domains[0], err.Error(), mainDomainSuffix, keyDatabase) } log.Debug().Msgf("Obtained certificate for %v", domains) if err := keyDatabase.Put(name, res); err != nil { return nil, err } tlsCertificate, err := tls.X509KeyPair(res.Certificate, res.PrivateKey) if err != nil { return nil, err } return &tlsCertificate, nil } func SetupMainDomainCertificates(mainDomainSuffix string, acmeClient *AcmeClient, certDB database.CertDB) error { // getting main cert before ACME account so that we can fail here without hitting rate limits mainCertBytes, err := certDB.Get(mainDomainSuffix) if err != nil && !errors.Is(err, database.ErrNotFound) { return fmt.Errorf("cert database is not working: %w", err) } if mainCertBytes == nil { _, err = acmeClient.obtainCert(acmeClient.dnsChallengerLegoClient, []string{"*" + mainDomainSuffix, mainDomainSuffix[1:]}, nil, "", true, mainDomainSuffix, certDB) if err != nil { log.Error().Err(err).Msg("Couldn't renew main domain certificate, continuing with mock certs only") } } return nil } func MaintainCertDB(ctx context.Context, interval time.Duration, acmeClient *AcmeClient, mainDomainSuffix string, certDB database.CertDB) { for { // delete expired certs that will be invalid until next clean up threshold := time.Now().Add(interval) expiredCertCount := 0 certs, err := certDB.Items(0, 0) if err != nil { log.Error().Err(err).Msg("could not get certs from list") } else { for _, cert := range certs { if !strings.EqualFold(cert.Domain, strings.TrimPrefix(mainDomainSuffix, ".")) { if time.Unix(cert.ValidTill, 0).Before(threshold) { err := certDB.Delete(cert.Domain) if err != nil { log.Error().Err(err).Msgf("Deleting expired certificate for %q failed", cert.Domain) } else { expiredCertCount++ } } } } log.Debug().Msgf("Removed %d expired certificates from the database", expiredCertCount) } // update main cert res, err := certDB.Get(mainDomainSuffix) if err != nil { log.Error().Msgf("Couldn't get cert for domain %q", mainDomainSuffix) } else if res == nil { log.Error().Msgf("Couldn't renew certificate for main domain %q expected main domain cert to exist, but it's missing - seems like the database is corrupted", mainDomainSuffix) } else { tlsCertificates, err := certcrypto.ParsePEMBundle(res.Certificate) if err != nil { log.Error().Err(fmt.Errorf("could not parse cert for mainDomainSuffix: %w", err)) } else if tlsCertificates[0].NotAfter.Before(time.Now().Add(30 * 24 * time.Hour)) { // renew main certificate 30 days before it expires go (func() { _, err = acmeClient.obtainCert(acmeClient.dnsChallengerLegoClient, []string{"*" + mainDomainSuffix, mainDomainSuffix[1:]}, res, "", true, mainDomainSuffix, certDB) if err != nil { log.Error().Err(err).Msg("Couldn't renew certificate for main domain") } })() } } select { case <-ctx.Done(): return case <-time.After(interval): } } } // leaf returns the parsed leaf certificate, either from c.leaf or by parsing // the corresponding c.Certificate[0]. func leaf(c *tls.Certificate) (*x509.Certificate, error) { if c.Leaf != nil { return c.Leaf, nil } return x509.ParseCertificate(c.Certificate[0]) }