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tailscale/client/web/web.go

543 lines
14 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package web provides the Tailscale client for web.
package web
import (
"bytes"
"context"
"crypto/rand"
"crypto/tls"
"embed"
"encoding/json"
"encoding/xml"
"fmt"
"html/template"
"io"
"log"
"net/http"
"net/http/httputil"
"net/netip"
"net/url"
"os"
"os/exec"
"strings"
"github.com/gorilla/csrf"
"tailscale.com/client/tailscale"
"tailscale.com/envknob"
"tailscale.com/ipn"
"tailscale.com/ipn/ipnstate"
"tailscale.com/licenses"
"tailscale.com/net/netutil"
"tailscale.com/tailcfg"
"tailscale.com/util/groupmember"
"tailscale.com/version/distro"
)
// This contains all files needed to build the frontend assets.
// Because we assign this to the blank identifier, it does not actually embed the files.
// However, this does cause `go mod vendor` to include the files when vendoring the package.
// External packages that use the web client can `go mod vendor`, run `yarn build` to
// build the assets, then those asset bundles will be able to be embedded.
//
//go:embed yarn.lock index.html *.js *.json src/*
var _ embed.FS
//go:embed web.html web.css
var embeddedFS embed.FS
var tmpls *template.Template
// Server is the backend server for a Tailscale web client.
type Server struct {
lc *tailscale.LocalClient
devMode bool
devProxy *httputil.ReverseProxy // only filled when devMode is on
apiHandler http.Handler // csrf-protected api handler
}
// NewServer constructs a new Tailscale web client server.
//
// lc is an optional parameter. When not filled, NewServer
// initializes its own tailscale.LocalClient.
func NewServer(devMode bool, lc *tailscale.LocalClient) (s *Server, cleanup func()) {
if lc == nil {
lc = &tailscale.LocalClient{}
}
s = &Server{
devMode: devMode,
lc: lc,
}
cleanup = func() {}
if s.devMode {
cleanup = s.startDevServer()
s.addProxyToDevServer()
// Create handler for "/api" requests with CSRF protection.
// We don't require secure cookies, since the web client is regularly used
// on network appliances that are served on local non-https URLs.
// The client is secured by limiting the interface it listens on,
// or by authenticating requests before they reach the web client.
csrfProtect := csrf.Protect(csrfKey(), csrf.Secure(false))
s.apiHandler = csrfProtect(&api{s: s})
}
s.lc.IncrementCounter(context.Background(), "web_client_initialization", 1)
return s, cleanup
}
func init() {
tmpls = template.Must(template.New("").ParseFS(embeddedFS, "*"))
}
// authorize returns the name of the user accessing the web UI after verifying
// whether the user has access to the web UI. The function will write the
// error to the provided http.ResponseWriter.
// Note: This is different from a tailscale user, and is typically the local
// user on the node.
func authorize(w http.ResponseWriter, r *http.Request) (string, error) {
switch distro.Get() {
case distro.Synology:
user, err := synoAuthn()
if err != nil {
http.Error(w, err.Error(), http.StatusUnauthorized)
return "", err
}
if err := authorizeSynology(user); err != nil {
http.Error(w, err.Error(), http.StatusForbidden)
return "", err
}
return user, nil
case distro.QNAP:
user, resp, err := qnapAuthn(r)
if err != nil {
http.Error(w, err.Error(), http.StatusUnauthorized)
return "", err
}
if resp.IsAdmin == 0 {
http.Error(w, err.Error(), http.StatusForbidden)
return "", err
}
return user, nil
}
return "", nil
}
// authorizeSynology checks whether the provided user has access to the web UI
// by consulting the membership of the "administrators" group.
func authorizeSynology(name string) error {
yes, err := groupmember.IsMemberOfGroup("administrators", name)
if err != nil {
return err
}
if !yes {
return fmt.Errorf("not a member of administrators group")
}
return nil
}
type qnapAuthResponse struct {
AuthPassed int `xml:"authPassed"`
IsAdmin int `xml:"isAdmin"`
AuthSID string `xml:"authSid"`
ErrorValue int `xml:"errorValue"`
}
func qnapAuthn(r *http.Request) (string, *qnapAuthResponse, error) {
user, err := r.Cookie("NAS_USER")
if err != nil {
return "", nil, err
}
token, err := r.Cookie("qtoken")
if err == nil {
return qnapAuthnQtoken(r, user.Value, token.Value)
}
sid, err := r.Cookie("NAS_SID")
if err == nil {
return qnapAuthnSid(r, user.Value, sid.Value)
}
return "", nil, fmt.Errorf("not authenticated by any mechanism")
}
// qnapAuthnURL returns the auth URL to use by inferring where the UI is
// running based on the request URL. This is necessary because QNAP has so
// many options, see https://github.com/tailscale/tailscale/issues/7108
// and https://github.com/tailscale/tailscale/issues/6903
func qnapAuthnURL(requestUrl string, query url.Values) string {
in, err := url.Parse(requestUrl)
scheme := ""
host := ""
if err != nil || in.Scheme == "" {
log.Printf("Cannot parse QNAP login URL %v", err)
// try localhost and hope for the best
scheme = "http"
host = "localhost"
} else {
scheme = in.Scheme
host = in.Host
}
u := url.URL{
Scheme: scheme,
Host: host,
Path: "/cgi-bin/authLogin.cgi",
RawQuery: query.Encode(),
}
return u.String()
}
func qnapAuthnQtoken(r *http.Request, user, token string) (string, *qnapAuthResponse, error) {
query := url.Values{
"qtoken": []string{token},
"user": []string{user},
}
return qnapAuthnFinish(user, qnapAuthnURL(r.URL.String(), query))
}
func qnapAuthnSid(r *http.Request, user, sid string) (string, *qnapAuthResponse, error) {
query := url.Values{
"sid": []string{sid},
}
return qnapAuthnFinish(user, qnapAuthnURL(r.URL.String(), query))
}
func qnapAuthnFinish(user, url string) (string, *qnapAuthResponse, error) {
// QNAP Force HTTPS mode uses a self-signed certificate. Even importing
// the QNAP root CA isn't enough, the cert doesn't have a usable CN nor
// SAN. See https://github.com/tailscale/tailscale/issues/6903
tr := &http.Transport{
TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
}
client := &http.Client{Transport: tr}
resp, err := client.Get(url)
if err != nil {
return "", nil, err
}
defer resp.Body.Close()
out, err := io.ReadAll(resp.Body)
if err != nil {
return "", nil, err
}
authResp := &qnapAuthResponse{}
if err := xml.Unmarshal(out, authResp); err != nil {
return "", nil, err
}
if authResp.AuthPassed == 0 {
return "", nil, fmt.Errorf("not authenticated")
}
return user, authResp, nil
}
func synoAuthn() (string, error) {
cmd := exec.Command("/usr/syno/synoman/webman/modules/authenticate.cgi")
out, err := cmd.CombinedOutput()
if err != nil {
return "", fmt.Errorf("auth: %v: %s", err, out)
}
return strings.TrimSpace(string(out)), nil
}
func authRedirect(w http.ResponseWriter, r *http.Request) bool {
if distro.Get() == distro.Synology {
return synoTokenRedirect(w, r)
}
return false
}
func synoTokenRedirect(w http.ResponseWriter, r *http.Request) bool {
if r.Header.Get("X-Syno-Token") != "" {
return false
}
if r.URL.Query().Get("SynoToken") != "" {
return false
}
if r.Method == "POST" && r.FormValue("SynoToken") != "" {
return false
}
// We need a SynoToken for authenticate.cgi.
// So we tell the client to get one.
_, _ = fmt.Fprint(w, synoTokenRedirectHTML)
return true
}
const synoTokenRedirectHTML = `<html><body>
Redirecting with session token...
<script>
var serverURL = window.location.protocol + "//" + window.location.host;
var req = new XMLHttpRequest();
req.overrideMimeType("application/json");
req.open("GET", serverURL + "/webman/login.cgi", true);
req.onload = function() {
var jsonResponse = JSON.parse(req.responseText);
var token = jsonResponse["SynoToken"];
document.location.href = serverURL + "/webman/3rdparty/Tailscale/?SynoToken=" + token;
};
req.send(null);
</script>
</body></html>
`
// ServeHTTP processes all requests for the Tailscale web client.
func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if s.devMode {
if strings.HasPrefix(r.URL.Path, "/api/") {
// Pass through to other handlers via CSRF protection.
s.apiHandler.ServeHTTP(w, r)
return
}
// When in dev mode, proxy to the Vite dev server.
s.devProxy.ServeHTTP(w, r)
return
}
if authRedirect(w, r) {
return
}
user, err := authorize(w, r)
if err != nil {
return
}
switch {
case r.Method == "POST":
s.servePostNodeUpdate(w, r)
return
default:
s.lc.IncrementCounter(context.Background(), "web_client_page_load", 1)
s.serveGetNodeData(w, r, user)
return
}
}
type nodeData struct {
Profile tailcfg.UserProfile
SynologyUser string
Status string
DeviceName string
IP string
AdvertiseExitNode bool
AdvertiseRoutes string
LicensesURL string
TUNMode bool
IsSynology bool
DSMVersion int // 6 or 7, if IsSynology=true
IsUnraid bool
UnraidToken string
IPNVersion string
}
func (s *Server) getNodeData(ctx context.Context, user string) (*nodeData, error) {
st, err := s.lc.Status(ctx)
if err != nil {
return nil, err
}
prefs, err := s.lc.GetPrefs(ctx)
if err != nil {
return nil, err
}
profile := st.User[st.Self.UserID]
deviceName := strings.Split(st.Self.DNSName, ".")[0]
versionShort := strings.Split(st.Version, "-")[0]
data := &nodeData{
SynologyUser: user,
Profile: profile,
Status: st.BackendState,
DeviceName: deviceName,
LicensesURL: licenses.LicensesURL(),
TUNMode: st.TUN,
IsSynology: distro.Get() == distro.Synology || envknob.Bool("TS_FAKE_SYNOLOGY"),
DSMVersion: distro.DSMVersion(),
IsUnraid: distro.Get() == distro.Unraid,
UnraidToken: os.Getenv("UNRAID_CSRF_TOKEN"),
IPNVersion: versionShort,
}
exitNodeRouteV4 := netip.MustParsePrefix("0.0.0.0/0")
exitNodeRouteV6 := netip.MustParsePrefix("::/0")
for _, r := range prefs.AdvertiseRoutes {
if r == exitNodeRouteV4 || r == exitNodeRouteV6 {
data.AdvertiseExitNode = true
} else {
if data.AdvertiseRoutes != "" {
data.AdvertiseRoutes += ","
}
data.AdvertiseRoutes += r.String()
}
}
if len(st.TailscaleIPs) != 0 {
data.IP = st.TailscaleIPs[0].String()
}
return data, nil
}
func (s *Server) serveGetNodeData(w http.ResponseWriter, r *http.Request, user string) {
data, err := s.getNodeData(r.Context(), user)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
buf := new(bytes.Buffer)
if err := tmpls.ExecuteTemplate(buf, "web.html", data); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Write(buf.Bytes())
}
func (s *Server) serveGetNodeDataJSON(w http.ResponseWriter, r *http.Request, user string) {
data, err := s.getNodeData(r.Context(), user)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if err := json.NewEncoder(w).Encode(*data); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json")
return
}
type nodeUpdate struct {
AdvertiseRoutes string
AdvertiseExitNode bool
Reauthenticate bool
ForceLogout bool
}
func (s *Server) servePostNodeUpdate(w http.ResponseWriter, r *http.Request) {
defer r.Body.Close()
st, err := s.lc.Status(r.Context())
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
var postData nodeUpdate
type mi map[string]any
if err := json.NewDecoder(r.Body).Decode(&postData); err != nil {
w.WriteHeader(400)
json.NewEncoder(w).Encode(mi{"error": err.Error()})
return
}
routes, err := netutil.CalcAdvertiseRoutes(postData.AdvertiseRoutes, postData.AdvertiseExitNode)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
json.NewEncoder(w).Encode(mi{"error": err.Error()})
return
}
mp := &ipn.MaskedPrefs{
AdvertiseRoutesSet: true,
WantRunningSet: true,
}
mp.Prefs.WantRunning = true
mp.Prefs.AdvertiseRoutes = routes
log.Printf("Doing edit: %v", mp.Pretty())
if _, err := s.lc.EditPrefs(r.Context(), mp); err != nil {
w.WriteHeader(http.StatusInternalServerError)
json.NewEncoder(w).Encode(mi{"error": err.Error()})
return
}
w.Header().Set("Content-Type", "application/json")
var reauth, logout bool
if postData.Reauthenticate {
reauth = true
}
if postData.ForceLogout {
logout = true
}
log.Printf("tailscaleUp(reauth=%v, logout=%v) ...", reauth, logout)
url, err := s.tailscaleUp(r.Context(), st, postData)
log.Printf("tailscaleUp = (URL %v, %v)", url != "", err)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
json.NewEncoder(w).Encode(mi{"error": err.Error()})
return
}
if url != "" {
json.NewEncoder(w).Encode(mi{"url": url})
} else {
io.WriteString(w, "{}")
}
return
}
func (s *Server) tailscaleUp(ctx context.Context, st *ipnstate.Status, postData nodeUpdate) (authURL string, retErr error) {
if postData.ForceLogout {
if err := s.lc.Logout(ctx); err != nil {
return "", fmt.Errorf("Logout error: %w", err)
}
return "", nil
}
origAuthURL := st.AuthURL
isRunning := st.BackendState == ipn.Running.String()
forceReauth := postData.Reauthenticate
if !forceReauth {
if origAuthURL != "" {
return origAuthURL, nil
}
if isRunning {
return "", nil
}
}
// printAuthURL reports whether we should print out the
// provided auth URL from an IPN notify.
printAuthURL := func(url string) bool {
return url != origAuthURL
}
watchCtx, cancelWatch := context.WithCancel(ctx)
defer cancelWatch()
watcher, err := s.lc.WatchIPNBus(watchCtx, 0)
if err != nil {
return "", err
}
defer watcher.Close()
go func() {
if !isRunning {
s.lc.Start(ctx, ipn.Options{})
}
if forceReauth {
s.lc.StartLoginInteractive(ctx)
}
}()
for {
n, err := watcher.Next()
if err != nil {
return "", err
}
if n.ErrMessage != nil {
msg := *n.ErrMessage
return "", fmt.Errorf("backend error: %v", msg)
}
if url := n.BrowseToURL; url != nil && printAuthURL(*url) {
return *url, nil
}
}
}
// csrfKey creates a new random csrf token.
// If an error surfaces during key creation,
// the error is logged and the active process terminated.
func csrfKey() []byte {
key := make([]byte, 32)
if _, err := rand.Read(key); err != nil {
log.Fatal("error generating CSRF key: %w", err)
}
return key
}