package home import ( "context" "crypto" "crypto/ecdsa" "crypto/ed25519" "crypto/rsa" "crypto/tls" "crypto/x509" "encoding/base64" "encoding/json" "encoding/pem" "fmt" "net/http" "os" "path/filepath" "runtime" "strings" "sync" "time" "github.com/AdguardTeam/AdGuardHome/internal/aghalg" "github.com/AdguardTeam/AdGuardHome/internal/aghhttp" "github.com/AdguardTeam/AdGuardHome/internal/dnsforward" "github.com/AdguardTeam/golibs/errors" "github.com/AdguardTeam/golibs/log" "github.com/google/go-cmp/cmp" ) var tlsWebHandlersRegistered = false // TLSMod - TLS module object type TLSMod struct { certLastMod time.Time // last modification time of the certificate file status tlsConfigStatus confLock sync.Mutex conf tlsConfigSettings } // Create TLS module func tlsCreate(conf tlsConfigSettings) *TLSMod { t := &TLSMod{} t.conf = conf if t.conf.Enabled { if !t.load() { // Something is not valid - return an empty TLS config return &TLSMod{conf: tlsConfigSettings{ Enabled: conf.Enabled, ServerName: conf.ServerName, PortHTTPS: conf.PortHTTPS, PortDNSOverTLS: conf.PortDNSOverTLS, PortDNSOverQUIC: conf.PortDNSOverQUIC, AllowUnencryptedDoH: conf.AllowUnencryptedDoH, }} } t.setCertFileTime() } return t } func (t *TLSMod) load() bool { if !tlsLoadConfig(&t.conf, &t.status) { log.Error("failed to load TLS config: %s", t.status.WarningValidation) return false } // validate current TLS config and update warnings (it could have been loaded from file) data := validateCertificates(string(t.conf.CertificateChainData), string(t.conf.PrivateKeyData), t.conf.ServerName) if !data.ValidPair { log.Error("failed to validate certificate: %s", data.WarningValidation) return false } t.status = data return true } // Close - close module func (t *TLSMod) Close() { } // WriteDiskConfig - write config func (t *TLSMod) WriteDiskConfig(conf *tlsConfigSettings) { t.confLock.Lock() *conf = t.conf t.confLock.Unlock() } func (t *TLSMod) setCertFileTime() { if len(t.conf.CertificatePath) == 0 { return } fi, err := os.Stat(t.conf.CertificatePath) if err != nil { log.Error("TLS: %s", err) return } t.certLastMod = fi.ModTime().UTC() } // Start updates the configuration of TLSMod and starts it. func (t *TLSMod) Start() { if !tlsWebHandlersRegistered { tlsWebHandlersRegistered = true t.registerWebHandlers() } t.confLock.Lock() tlsConf := t.conf t.confLock.Unlock() // The background context is used because the TLSConfigChanged wraps // context with timeout on its own and shuts down the server, which // handles current request. Context.web.TLSConfigChanged(context.Background(), tlsConf) } // Reload updates the configuration of TLSMod and restarts it. func (t *TLSMod) Reload() { t.confLock.Lock() tlsConf := t.conf t.confLock.Unlock() if !tlsConf.Enabled || len(tlsConf.CertificatePath) == 0 { return } fi, err := os.Stat(tlsConf.CertificatePath) if err != nil { log.Error("TLS: %s", err) return } if fi.ModTime().UTC().Equal(t.certLastMod) { log.Debug("TLS: certificate file isn't modified") return } log.Debug("TLS: certificate file is modified") t.confLock.Lock() r := t.load() t.confLock.Unlock() if !r { return } t.certLastMod = fi.ModTime().UTC() _ = reconfigureDNSServer() t.confLock.Lock() tlsConf = t.conf t.confLock.Unlock() // The background context is used because the TLSConfigChanged wraps // context with timeout on its own and shuts down the server, which // handles current request. Context.web.TLSConfigChanged(context.Background(), tlsConf) } // Set certificate and private key data func tlsLoadConfig(tls *tlsConfigSettings, status *tlsConfigStatus) bool { tls.CertificateChainData = []byte(tls.CertificateChain) tls.PrivateKeyData = []byte(tls.PrivateKey) var err error if tls.CertificatePath != "" { if tls.CertificateChain != "" { status.WarningValidation = "certificate data and file can't be set together" return false } tls.CertificateChainData, err = os.ReadFile(tls.CertificatePath) if err != nil { status.WarningValidation = err.Error() return false } status.ValidCert = true } if tls.PrivateKeyPath != "" { if tls.PrivateKey != "" { status.WarningValidation = "private key data and file can't be set together" return false } tls.PrivateKeyData, err = os.ReadFile(tls.PrivateKeyPath) if err != nil { status.WarningValidation = err.Error() return false } status.ValidKey = true } return true } type tlsConfigStatus struct { ValidCert bool `json:"valid_cert"` // ValidCert is true if the specified certificates chain is a valid chain of X509 certificates ValidChain bool `json:"valid_chain"` // ValidChain is true if the specified certificates chain is verified and issued by a known CA Subject string `json:"subject,omitempty"` // Subject is the subject of the first certificate in the chain Issuer string `json:"issuer,omitempty"` // Issuer is the issuer of the first certificate in the chain NotBefore time.Time `json:"not_before,omitempty"` // NotBefore is the NotBefore field of the first certificate in the chain NotAfter time.Time `json:"not_after,omitempty"` // NotAfter is the NotAfter field of the first certificate in the chain DNSNames []string `json:"dns_names"` // DNSNames is the value of SubjectAltNames field of the first certificate in the chain // key status ValidKey bool `json:"valid_key"` // ValidKey is true if the key is a valid private key KeyType string `json:"key_type,omitempty"` // KeyType is one of RSA or ECDSA // is usable? set by validator ValidPair bool `json:"valid_pair"` // ValidPair is true if both certificate and private key are correct // warnings WarningValidation string `json:"warning_validation,omitempty"` // WarningValidation is a validation warning message with the issue description } // field ordering is important -- yaml fields will mirror ordering from here type tlsConfig struct { tlsConfigStatus `json:",inline"` tlsConfigSettingsExt `json:",inline"` } // tlsConfigSettingsExt is used to (un)marshal PrivateKeySaved to ensure that // clients don't send and receive previously saved private keys. type tlsConfigSettingsExt struct { tlsConfigSettings `json:",inline"` // If private key saved as a string, we set this flag to true // and omit key from answer. PrivateKeySaved bool `yaml:"-" json:"private_key_saved,inline"` } func (t *TLSMod) handleTLSStatus(w http.ResponseWriter, r *http.Request) { t.confLock.Lock() data := tlsConfig{ tlsConfigSettingsExt: tlsConfigSettingsExt{ tlsConfigSettings: t.conf, }, tlsConfigStatus: t.status, } t.confLock.Unlock() marshalTLS(w, r, data) } func (t *TLSMod) handleTLSValidate(w http.ResponseWriter, r *http.Request) { setts, err := unmarshalTLS(r) if err != nil { aghhttp.Error(r, w, http.StatusBadRequest, "Failed to unmarshal TLS config: %s", err) return } if setts.PrivateKeySaved { setts.PrivateKey = t.conf.PrivateKey } if setts.Enabled { err = validatePorts( tcpPort(config.BindPort), tcpPort(config.BetaBindPort), tcpPort(setts.PortHTTPS), tcpPort(setts.PortDNSOverTLS), tcpPort(setts.PortDNSCrypt), udpPort(config.DNS.Port), udpPort(setts.PortDNSOverQUIC), ) if err != nil { aghhttp.Error(r, w, http.StatusBadRequest, "%s", err) return } } if !WebCheckPortAvailable(setts.PortHTTPS) { aghhttp.Error( r, w, http.StatusBadRequest, "port %d is not available, cannot enable HTTPS on it", setts.PortHTTPS, ) return } status := tlsConfigStatus{} if tlsLoadConfig(&setts.tlsConfigSettings, &status) { status = validateCertificates(string(setts.CertificateChainData), string(setts.PrivateKeyData), setts.ServerName) } data := tlsConfig{ tlsConfigSettingsExt: setts, tlsConfigStatus: status, } marshalTLS(w, r, data) } func (t *TLSMod) setConfig(newConf tlsConfigSettings, status tlsConfigStatus) (restartHTTPS bool) { t.confLock.Lock() defer t.confLock.Unlock() // Reset the DNSCrypt data before comparing, since we currently do not // accept these from the frontend. // // TODO(a.garipov): Define a custom comparer for dnsforward.TLSConfig. newConf.DNSCryptConfigFile = t.conf.DNSCryptConfigFile newConf.PortDNSCrypt = t.conf.PortDNSCrypt if !cmp.Equal(t.conf, newConf, cmp.AllowUnexported(dnsforward.TLSConfig{})) { log.Info("tls config has changed, restarting https server") restartHTTPS = true } else { log.Info("tls config has not changed") } // Note: don't do just `t.conf = data` because we must preserve all other members of t.conf t.conf.Enabled = newConf.Enabled t.conf.ServerName = newConf.ServerName t.conf.ForceHTTPS = newConf.ForceHTTPS t.conf.PortHTTPS = newConf.PortHTTPS t.conf.PortDNSOverTLS = newConf.PortDNSOverTLS t.conf.PortDNSOverQUIC = newConf.PortDNSOverQUIC t.conf.CertificateChain = newConf.CertificateChain t.conf.CertificatePath = newConf.CertificatePath t.conf.CertificateChainData = newConf.CertificateChainData t.conf.PrivateKey = newConf.PrivateKey t.conf.PrivateKeyPath = newConf.PrivateKeyPath t.conf.PrivateKeyData = newConf.PrivateKeyData t.status = status return restartHTTPS } func (t *TLSMod) handleTLSConfigure(w http.ResponseWriter, r *http.Request) { data, err := unmarshalTLS(r) if err != nil { aghhttp.Error(r, w, http.StatusBadRequest, "Failed to unmarshal TLS config: %s", err) return } if data.PrivateKeySaved { data.PrivateKey = t.conf.PrivateKey } if data.Enabled { err = validatePorts( tcpPort(config.BindPort), tcpPort(config.BetaBindPort), tcpPort(data.PortHTTPS), tcpPort(data.PortDNSOverTLS), tcpPort(data.PortDNSCrypt), udpPort(config.DNS.Port), udpPort(data.PortDNSOverQUIC), ) if err != nil { aghhttp.Error(r, w, http.StatusBadRequest, "%s", err) return } } // TODO(e.burkov): Investigate and perhaps check other ports. if !WebCheckPortAvailable(data.PortHTTPS) { aghhttp.Error( r, w, http.StatusBadRequest, "port %d is not available, cannot enable HTTPS on it", data.PortHTTPS, ) return } status := tlsConfigStatus{} if !tlsLoadConfig(&data.tlsConfigSettings, &status) { data2 := tlsConfig{ tlsConfigSettingsExt: data, tlsConfigStatus: t.status, } marshalTLS(w, r, data2) return } status = validateCertificates(string(data.CertificateChainData), string(data.PrivateKeyData), data.ServerName) restartHTTPS := t.setConfig(data.tlsConfigSettings, status) t.setCertFileTime() onConfigModified() err = reconfigureDNSServer() if err != nil { aghhttp.Error(r, w, http.StatusInternalServerError, "%s", err) return } data2 := tlsConfig{ tlsConfigSettingsExt: data, tlsConfigStatus: t.status, } marshalTLS(w, r, data2) if f, ok := w.(http.Flusher); ok { f.Flush() } // The background context is used because the TLSConfigChanged wraps context // with timeout on its own and shuts down the server, which handles current // request. It is also should be done in a separate goroutine due to the // same reason. if restartHTTPS { go func() { Context.web.TLSConfigChanged(context.Background(), data.tlsConfigSettings) }() } } // validatePorts validates the uniqueness of TCP and UDP ports for AdGuard Home // DNS protocols. func validatePorts( bindPort, betaBindPort, dohPort, dotPort, dnscryptTCPPort tcpPort, dnsPort, doqPort udpPort, ) (err error) { tcpPorts := aghalg.UniqChecker[tcpPort]{} addPorts( tcpPorts, tcpPort(bindPort), tcpPort(betaBindPort), tcpPort(dohPort), tcpPort(dotPort), tcpPort(dnscryptTCPPort), ) err = tcpPorts.Validate() if err != nil { return fmt.Errorf("validating tcp ports: %w", err) } udpPorts := aghalg.UniqChecker[udpPort]{} addPorts(udpPorts, udpPort(dnsPort), udpPort(doqPort)) err = udpPorts.Validate() if err != nil { return fmt.Errorf("validating udp ports: %w", err) } return nil } func verifyCertChain(data *tlsConfigStatus, certChain, serverName string) error { log.Tracef("TLS: got certificate: %d bytes", len(certChain)) // now do a more extended validation var certs []*pem.Block // PEM-encoded certificates pemblock := []byte(certChain) for { var decoded *pem.Block decoded, pemblock = pem.Decode(pemblock) if decoded == nil { break } if decoded.Type == "CERTIFICATE" { certs = append(certs, decoded) } } var parsedCerts []*x509.Certificate for _, cert := range certs { parsed, err := x509.ParseCertificate(cert.Bytes) if err != nil { data.WarningValidation = fmt.Sprintf("Failed to parse certificate: %s", err) return errors.Error(data.WarningValidation) } parsedCerts = append(parsedCerts, parsed) } if len(parsedCerts) == 0 { data.WarningValidation = "You have specified an empty certificate" return errors.Error(data.WarningValidation) } data.ValidCert = true // spew.Dump(parsedCerts) opts := x509.VerifyOptions{ DNSName: serverName, Roots: Context.tlsRoots, } log.Printf("number of certs - %d", len(parsedCerts)) if len(parsedCerts) > 1 { // set up an intermediate pool := x509.NewCertPool() for _, cert := range parsedCerts[1:] { log.Printf("got an intermediate cert") pool.AddCert(cert) } opts.Intermediates = pool } // TODO: save it as a warning rather than error it out -- shouldn't be a big problem mainCert := parsedCerts[0] _, err := mainCert.Verify(opts) if err != nil { // let self-signed certs through data.WarningValidation = fmt.Sprintf("Your certificate does not verify: %s", err) } else { data.ValidChain = true } // spew.Dump(chains) // update status if mainCert != nil { notAfter := mainCert.NotAfter data.Subject = mainCert.Subject.String() data.Issuer = mainCert.Issuer.String() data.NotAfter = notAfter data.NotBefore = mainCert.NotBefore data.DNSNames = mainCert.DNSNames } return nil } func validatePkey(data *tlsConfigStatus, pkey string) error { // now do a more extended validation var key *pem.Block // PEM-encoded certificates // go through all pem blocks, but take first valid pem block and drop the rest pemblock := []byte(pkey) for { var decoded *pem.Block decoded, pemblock = pem.Decode(pemblock) if decoded == nil { break } if decoded.Type == "PRIVATE KEY" || strings.HasSuffix(decoded.Type, " PRIVATE KEY") { key = decoded break } } if key == nil { data.WarningValidation = "No valid keys were found" return errors.Error(data.WarningValidation) } // parse the decoded key _, keyType, err := parsePrivateKey(key.Bytes) if err != nil { data.WarningValidation = fmt.Sprintf("Failed to parse private key: %s", err) return errors.Error(data.WarningValidation) } else if keyType == keyTypeED25519 { data.WarningValidation = "ED25519 keys are not supported by browsers; " + "did you mean to use X25519 for key exchange?" return errors.Error(data.WarningValidation) } data.ValidKey = true data.KeyType = keyType return nil } // Process certificate data and its private key. // All parameters are optional. // On error, return partially set object // with 'WarningValidation' field containing error description. func validateCertificates(certChain, pkey, serverName string) tlsConfigStatus { var data tlsConfigStatus // check only public certificate separately from the key if certChain != "" { if verifyCertChain(&data, certChain, serverName) != nil { return data } } // validate private key (right now the only validation possible is just parsing it) if pkey != "" { if validatePkey(&data, pkey) != nil { return data } } // if both are set, validate both in unison if pkey != "" && certChain != "" { _, err := tls.X509KeyPair([]byte(certChain), []byte(pkey)) if err != nil { data.WarningValidation = fmt.Sprintf("Invalid certificate or key: %s", err) return data } data.ValidPair = true } return data } // Key types. const ( keyTypeECDSA = "ECDSA" keyTypeED25519 = "ED25519" keyTypeRSA = "RSA" ) // Attempt to parse the given private key DER block. OpenSSL 0.9.8 generates // PKCS#1 private keys by default, while OpenSSL 1.0.0 generates PKCS#8 keys. // OpenSSL ecparam generates SEC1 EC private keys for ECDSA. We try all three. // // TODO(a.garipov): Find out if this version of parsePrivateKey from the stdlib // is actually necessary. func parsePrivateKey(der []byte) (key crypto.PrivateKey, typ string, err error) { if key, err = x509.ParsePKCS1PrivateKey(der); err == nil { return key, keyTypeRSA, nil } if key, err = x509.ParsePKCS8PrivateKey(der); err == nil { switch key := key.(type) { case *rsa.PrivateKey: return key, keyTypeRSA, nil case *ecdsa.PrivateKey: return key, keyTypeECDSA, nil case ed25519.PrivateKey: return key, keyTypeED25519, nil default: return nil, "", fmt.Errorf( "tls: found unknown private key type %T in PKCS#8 wrapping", key, ) } } if key, err = x509.ParseECPrivateKey(der); err == nil { return key, keyTypeECDSA, nil } return nil, "", errors.Error("tls: failed to parse private key") } // unmarshalTLS handles base64-encoded certificates transparently func unmarshalTLS(r *http.Request) (tlsConfigSettingsExt, error) { data := tlsConfigSettingsExt{} err := json.NewDecoder(r.Body).Decode(&data) if err != nil { return data, fmt.Errorf("failed to parse new TLS config json: %w", err) } if data.CertificateChain != "" { var cert []byte cert, err = base64.StdEncoding.DecodeString(data.CertificateChain) if err != nil { return data, fmt.Errorf("failed to base64-decode certificate chain: %w", err) } data.CertificateChain = string(cert) if data.CertificatePath != "" { return data, fmt.Errorf("certificate data and file can't be set together") } } if data.PrivateKey != "" { var key []byte key, err = base64.StdEncoding.DecodeString(data.PrivateKey) if err != nil { return data, fmt.Errorf("failed to base64-decode private key: %w", err) } data.PrivateKey = string(key) if data.PrivateKeyPath != "" { return data, fmt.Errorf("private key data and file can't be set together") } } return data, nil } func marshalTLS(w http.ResponseWriter, r *http.Request, data tlsConfig) { w.Header().Set("Content-Type", "application/json") if data.CertificateChain != "" { encoded := base64.StdEncoding.EncodeToString([]byte(data.CertificateChain)) data.CertificateChain = encoded } if data.PrivateKey != "" { data.PrivateKeySaved = true data.PrivateKey = "" } err := json.NewEncoder(w).Encode(data) if err != nil { aghhttp.Error( r, w, http.StatusInternalServerError, "Failed to marshal json with TLS status: %s", err, ) } } // registerWebHandlers registers HTTP handlers for TLS configuration func (t *TLSMod) registerWebHandlers() { httpRegister(http.MethodGet, "/control/tls/status", t.handleTLSStatus) httpRegister(http.MethodPost, "/control/tls/configure", t.handleTLSConfigure) httpRegister(http.MethodPost, "/control/tls/validate", t.handleTLSValidate) } // LoadSystemRootCAs tries to load root certificates from the operating system. // It returns nil in case nothing is found so that that Go.crypto will use it's // default algorithm to find system root CA list. // // See https://github.com/AdguardTeam/AdGuardHome/internal/issues/1311. func LoadSystemRootCAs() (roots *x509.CertPool) { // TODO(e.burkov): Use build tags instead. if runtime.GOOS != "linux" { return nil } // Directories with the system root certificates, which aren't supported // by Go.crypto. dirs := []string{ // Entware. "/opt/etc/ssl/certs", } roots = x509.NewCertPool() for _, dir := range dirs { dirEnts, err := os.ReadDir(dir) if errors.Is(err, os.ErrNotExist) { continue } else if err != nil { log.Error("opening directory: %q: %s", dir, err) } var rootsAdded bool for _, de := range dirEnts { var certData []byte certData, err = os.ReadFile(filepath.Join(dir, de.Name())) if err == nil && roots.AppendCertsFromPEM(certData) { rootsAdded = true } } if rootsAdded { return roots } } return nil }