AdGuardHome/internal/home/tls.go

782 lines
20 KiB
Go

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"
"strings"
"sync"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/aghalg"
"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
"github.com/AdguardTeam/AdGuardHome/internal/aghtls"
"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
"github.com/google/go-cmp/cmp"
)
// tlsManager contains the current configuration and state of AdGuard Home TLS
// encryption.
type tlsManager struct {
// status is the current status of the configuration. It is never nil.
status *tlsConfigStatus
// certLastMod is the last modification time of the certificate file.
certLastMod time.Time
confLock sync.Mutex
conf tlsConfigSettings
}
// newTLSManager initializes the manager of TLS configuration. m is always
// non-nil while any returned error indicates that the TLS configuration isn't
// valid. Thus TLS may be initialized later, e.g. via the web UI.
func newTLSManager(conf tlsConfigSettings) (m *tlsManager, err error) {
m = &tlsManager{
status: &tlsConfigStatus{},
conf: conf,
}
if m.conf.Enabled {
err = m.load()
if err != nil {
m.conf.Enabled = false
return m, err
}
m.setCertFileTime()
}
return m, nil
}
// load reloads the TLS configuration from files or data from the config file.
func (m *tlsManager) load() (err error) {
err = loadTLSConf(&m.conf, m.status)
if err != nil {
return fmt.Errorf("loading config: %w", err)
}
return nil
}
// WriteDiskConfig - write config
func (m *tlsManager) WriteDiskConfig(conf *tlsConfigSettings) {
m.confLock.Lock()
*conf = m.conf
m.confLock.Unlock()
}
// setCertFileTime sets t.certLastMod from the certificate. If there are
// errors, setCertFileTime logs them.
func (m *tlsManager) setCertFileTime() {
if len(m.conf.CertificatePath) == 0 {
return
}
fi, err := os.Stat(m.conf.CertificatePath)
if err != nil {
log.Error("tls: looking up certificate path: %s", err)
return
}
m.certLastMod = fi.ModTime().UTC()
}
// start updates the configuration of t and starts it.
func (m *tlsManager) start() {
m.registerWebHandlers()
m.confLock.Lock()
tlsConf := m.conf
m.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 and restarts t.
func (m *tlsManager) reload() {
m.confLock.Lock()
tlsConf := m.conf
m.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(m.certLastMod) {
log.Debug("tls: certificate file isn't modified")
return
}
log.Debug("tls: certificate file is modified")
m.confLock.Lock()
err = m.load()
m.confLock.Unlock()
if err != nil {
log.Error("tls: reloading: %s", err)
return
}
m.certLastMod = fi.ModTime().UTC()
_ = reconfigureDNSServer()
m.confLock.Lock()
tlsConf = m.conf
m.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)
}
// loadTLSConf loads and validates the TLS configuration. The returned error is
// also set in status.WarningValidation.
func loadTLSConf(tlsConf *tlsConfigSettings, status *tlsConfigStatus) (err error) {
defer func() {
if err != nil {
status.WarningValidation = err.Error()
if status.ValidCert && status.ValidKey && status.ValidPair {
// Do not return warnings since those aren't critical.
err = nil
}
}
}()
err = loadCertificateChainData(tlsConf, status)
if err != nil {
// Don't wrap the error, because it's informative enough as is.
return err
}
err = loadPrivateKeyData(tlsConf, status)
if err != nil {
// Don't wrap the error, because it's informative enough as is.
return err
}
err = validateCertificates(
status,
tlsConf.CertificateChainData,
tlsConf.PrivateKeyData,
tlsConf.ServerName,
)
return errors.Annotate(err, "validating certificate pair: %w")
}
// loadCertificateChainData loads PEM-encoded certificates chain data to the
// TLS configuration.
func loadCertificateChainData(tlsConf *tlsConfigSettings, status *tlsConfigStatus) (err error) {
tlsConf.CertificateChainData = []byte(tlsConf.CertificateChain)
if tlsConf.CertificatePath != "" {
if tlsConf.CertificateChain != "" {
return errors.Error("certificate data and file can't be set together")
}
tlsConf.CertificateChainData, err = os.ReadFile(tlsConf.CertificatePath)
if err != nil {
return fmt.Errorf("reading cert file: %w", err)
}
// Set status.ValidCert to true to signal the frontend that the
// certificate opens successfully while the private key can't be opened.
status.ValidCert = true
}
return nil
}
// loadPrivateKeyData loads PEM-encoded private key data to the TLS
// configuration.
func loadPrivateKeyData(tlsConf *tlsConfigSettings, status *tlsConfigStatus) (err error) {
tlsConf.PrivateKeyData = []byte(tlsConf.PrivateKey)
if tlsConf.PrivateKeyPath != "" {
if tlsConf.PrivateKey != "" {
return errors.Error("private key data and file can't be set together")
}
tlsConf.PrivateKeyData, err = os.ReadFile(tlsConf.PrivateKeyPath)
if err != nil {
return fmt.Errorf("reading key file: %w", err)
}
status.ValidKey = true
}
return nil
}
// tlsConfigStatus contains the status of a certificate chain and key pair.
type tlsConfigStatus struct {
// Subject is the subject of the first certificate in the chain.
Subject string `json:"subject,omitempty"`
// Issuer is the issuer of the first certificate in the chain.
Issuer string `json:"issuer,omitempty"`
// KeyType is the type of the private key.
KeyType string `json:"key_type,omitempty"`
// NotBefore is the NotBefore field of the first certificate in the chain.
NotBefore time.Time `json:"not_before,omitempty"`
// NotAfter is the NotAfter field of the first certificate in the chain.
NotAfter time.Time `json:"not_after,omitempty"`
// WarningValidation is a validation warning message with the issue
// description.
WarningValidation string `json:"warning_validation,omitempty"`
// DNSNames is the value of SubjectAltNames field of the first certificate
// in the chain.
DNSNames []string `json:"dns_names"`
// ValidCert is true if the specified certificate chain is a valid chain of
// X509 certificates.
ValidCert bool `json:"valid_cert"`
// ValidChain is true if the specified certificate chain is verified and
// issued by a known CA.
ValidChain bool `json:"valid_chain"`
// ValidKey is true if the key is a valid private key.
ValidKey bool `json:"valid_key"`
// ValidPair is true if both certificate and private key are correct for
// each other.
ValidPair bool `json:"valid_pair"`
}
// tlsConfig is the TLS configuration and status response.
type tlsConfig struct {
*tlsConfigStatus `json:",inline"`
tlsConfigSettingsExt `json:",inline"`
}
// tlsConfigSettingsExt is used to (un)marshal the PrivateKeySaved field to
// ensure that clients don't send and receive previously saved private keys.
type tlsConfigSettingsExt struct {
tlsConfigSettings `json:",inline"`
// PrivateKeySaved is true if the private key is saved as a string and omit
// key from answer.
PrivateKeySaved bool `yaml:"-" json:"private_key_saved,inline"`
}
func (m *tlsManager) handleTLSStatus(w http.ResponseWriter, r *http.Request) {
m.confLock.Lock()
data := tlsConfig{
tlsConfigSettingsExt: tlsConfigSettingsExt{
tlsConfigSettings: m.conf,
},
tlsConfigStatus: m.status,
}
m.confLock.Unlock()
marshalTLS(w, r, data)
}
func (m *tlsManager) 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 = m.conf.PrivateKey
}
if setts.Enabled {
err = validatePorts(
tcpPort(config.HTTPConfig.Address.Port()),
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
}
// Skip the error check, since we are only interested in the value of
// status.WarningValidation.
status := &tlsConfigStatus{}
_ = loadTLSConf(&setts.tlsConfigSettings, status)
resp := tlsConfig{
tlsConfigSettingsExt: setts,
tlsConfigStatus: status,
}
marshalTLS(w, r, resp)
}
func (m *tlsManager) setConfig(newConf tlsConfigSettings, status *tlsConfigStatus) (restartHTTPS bool) {
m.confLock.Lock()
defer m.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 = m.conf.DNSCryptConfigFile
newConf.PortDNSCrypt = m.conf.PortDNSCrypt
if !cmp.Equal(m.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
m.conf.Enabled = newConf.Enabled
m.conf.ServerName = newConf.ServerName
m.conf.ForceHTTPS = newConf.ForceHTTPS
m.conf.PortHTTPS = newConf.PortHTTPS
m.conf.PortDNSOverTLS = newConf.PortDNSOverTLS
m.conf.PortDNSOverQUIC = newConf.PortDNSOverQUIC
m.conf.CertificateChain = newConf.CertificateChain
m.conf.CertificatePath = newConf.CertificatePath
m.conf.CertificateChainData = newConf.CertificateChainData
m.conf.PrivateKey = newConf.PrivateKey
m.conf.PrivateKeyPath = newConf.PrivateKeyPath
m.conf.PrivateKeyData = newConf.PrivateKeyData
m.status = status
return restartHTTPS
}
func (m *tlsManager) handleTLSConfigure(w http.ResponseWriter, r *http.Request) {
req, err := unmarshalTLS(r)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "Failed to unmarshal TLS config: %s", err)
return
}
if req.PrivateKeySaved {
req.PrivateKey = m.conf.PrivateKey
}
if req.Enabled {
err = validatePorts(
tcpPort(config.HTTPConfig.Address.Port()),
tcpPort(req.PortHTTPS),
tcpPort(req.PortDNSOverTLS),
tcpPort(req.PortDNSCrypt),
udpPort(config.DNS.Port),
udpPort(req.PortDNSOverQUIC),
)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
return
}
}
// TODO(e.burkov): Investigate and perhaps check other ports.
if !webCheckPortAvailable(req.PortHTTPS) {
aghhttp.Error(
r,
w,
http.StatusBadRequest,
"port %d is not available, cannot enable https on it",
req.PortHTTPS,
)
return
}
status := &tlsConfigStatus{}
err = loadTLSConf(&req.tlsConfigSettings, status)
if err != nil {
resp := tlsConfig{
tlsConfigSettingsExt: req,
tlsConfigStatus: status,
}
marshalTLS(w, r, resp)
return
}
restartHTTPS := m.setConfig(req.tlsConfigSettings, status)
m.setCertFileTime()
onConfigModified()
err = reconfigureDNSServer()
if err != nil {
aghhttp.Error(r, w, http.StatusInternalServerError, "%s", err)
return
}
resp := tlsConfig{
tlsConfigSettingsExt: req,
tlsConfigStatus: m.status,
}
marshalTLS(w, r, resp)
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(), req.tlsConfigSettings)
}()
}
}
// validatePorts validates the uniqueness of TCP and UDP ports for AdGuard Home
// DNS protocols.
func validatePorts(
bindPort, dohPort, dotPort, dnscryptTCPPort tcpPort,
dnsPort, doqPort udpPort,
) (err error) {
tcpPorts := aghalg.UniqChecker[tcpPort]{}
addPorts(
tcpPorts,
tcpPort(bindPort),
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
}
// validateCertChain verifies certs using the first as the main one and others
// as intermediate. srvName stands for the expected DNS name.
func validateCertChain(certs []*x509.Certificate, srvName string) (err error) {
main, others := certs[0], certs[1:]
pool := x509.NewCertPool()
for _, cert := range others {
log.Info("tls: got an intermediate cert")
pool.AddCert(cert)
}
opts := x509.VerifyOptions{
DNSName: srvName,
Roots: Context.tlsRoots,
Intermediates: pool,
}
_, err = main.Verify(opts)
if err != nil {
return fmt.Errorf("certificate does not verify: %w", err)
}
return nil
}
// errNoIPInCert is the error that is returned from [parseCertChain] if the leaf
// certificate doesn't contain IPs.
const errNoIPInCert errors.Error = `certificates has no IP addresses; ` +
`DNS-over-TLS won't be advertised via DDR`
// parseCertChain parses the certificate chain from raw data, and returns it.
// If ok is true, the returned error, if any, is not critical.
func parseCertChain(chain []byte) (parsedCerts []*x509.Certificate, ok bool, err error) {
log.Debug("tls: got certificate chain: %d bytes", len(chain))
var certs []*pem.Block
for decoded, pemblock := pem.Decode(chain); decoded != nil; {
if decoded.Type == "CERTIFICATE" {
certs = append(certs, decoded)
}
decoded, pemblock = pem.Decode(pemblock)
}
parsedCerts, err = parsePEMCerts(certs)
if err != nil {
return nil, false, err
}
log.Info("tls: number of certs: %d", len(parsedCerts))
if !aghtls.CertificateHasIP(parsedCerts[0]) {
err = errNoIPInCert
}
return parsedCerts, true, err
}
// parsePEMCerts parses multiple PEM-encoded certificates.
func parsePEMCerts(certs []*pem.Block) (parsedCerts []*x509.Certificate, err error) {
for i, cert := range certs {
var parsed *x509.Certificate
parsed, err = x509.ParseCertificate(cert.Bytes)
if err != nil {
return nil, fmt.Errorf("parsing certificate at index %d: %w", i, err)
}
parsedCerts = append(parsedCerts, parsed)
}
if len(parsedCerts) == 0 {
return nil, errors.Error("empty certificate")
}
return parsedCerts, nil
}
// validatePKey validates the private key, returning its type. It returns an
// empty string if error occurs.
func validatePKey(pkey []byte) (keyType string, err error) {
var key *pem.Block
// Go through all pem blocks, but take first valid pem block and drop the
// rest.
for decoded, pemblock := pem.Decode([]byte(pkey)); decoded != nil; {
if decoded.Type == "PRIVATE KEY" || strings.HasSuffix(decoded.Type, " PRIVATE KEY") {
key = decoded
break
}
decoded, pemblock = pem.Decode(pemblock)
}
if key == nil {
return "", errors.Error("no valid keys were found")
}
_, keyType, err = parsePrivateKey(key.Bytes)
if err != nil {
return "", fmt.Errorf("parsing private key: %w", err)
}
if keyType == keyTypeED25519 {
return "", errors.Error(
"ED25519 keys are not supported by browsers; " +
"did you mean to use X25519 for key exchange?",
)
}
return keyType, nil
}
// validateCertificates processes certificate data and its private key. status
// must not be nil, since it's used to accumulate the validation results. Other
// parameters are optional.
func validateCertificates(
status *tlsConfigStatus,
certChain []byte,
pkey []byte,
serverName string,
) (err error) {
// Check only the public certificate separately from the key.
if len(certChain) > 0 {
var certs []*x509.Certificate
certs, status.ValidCert, err = parseCertChain(certChain)
if !status.ValidCert {
// Don't wrap the error, since it's informative enough as is.
return err
}
mainCert := certs[0]
status.Subject = mainCert.Subject.String()
status.Issuer = mainCert.Issuer.String()
status.NotAfter = mainCert.NotAfter
status.NotBefore = mainCert.NotBefore
status.DNSNames = mainCert.DNSNames
if chainErr := validateCertChain(certs, serverName); chainErr != nil {
// Let self-signed certs through and don't return this error to set
// its message into the status.WarningValidation afterwards.
err = chainErr
} else {
status.ValidChain = true
}
}
// Validate the private key by parsing it.
if len(pkey) > 0 {
var keyErr error
status.KeyType, keyErr = validatePKey(pkey)
if keyErr != nil {
// Don't wrap the error, since it's informative enough as is.
return keyErr
}
status.ValidKey = true
}
// If both are set, validate together.
if len(certChain) > 0 && len(pkey) > 0 {
_, pairErr := tls.X509KeyPair(certChain, pkey)
if pairErr != nil {
return fmt.Errorf("certificate-key pair: %w", pairErr)
}
status.ValidPair = true
}
return err
}
// 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) {
if data.CertificateChain != "" {
encoded := base64.StdEncoding.EncodeToString([]byte(data.CertificateChain))
data.CertificateChain = encoded
}
if data.PrivateKey != "" {
data.PrivateKeySaved = true
data.PrivateKey = ""
}
_ = aghhttp.WriteJSONResponse(w, r, data)
}
// registerWebHandlers registers HTTP handlers for TLS configuration.
func (m *tlsManager) registerWebHandlers() {
httpRegister(http.MethodGet, "/control/tls/status", m.handleTLSStatus)
httpRegister(http.MethodPost, "/control/tls/configure", m.handleTLSConfigure)
httpRegister(http.MethodPost, "/control/tls/validate", m.handleTLSValidate)
}