tailscale/client/web/web.go
Will Norris 0df5507c81 client/web: combine embeds into a single embed.FS
instead of embedding each file individually, embed them all into a
single embed filesystem.  This is basically a noop for the current
frontend, but sets things up a little cleaner for the new frontend.

Also added an embed.FS for the source files needed to build the new
frontend. These files are not actually embedded into the binary (since
it is a blank identifier), but causes `go mod vendor` to copy them into
the vendor directory.

Updates tailscale/corp#13775

Signed-off-by: Will Norris <will@tailscale.com>
2023-08-22 11:17:16 -07:00

545 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 auth-redirect.html
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 new handler for "/api" requests.
// And protect with gorilla csrf.
csrfProtect := csrf.Protect(csrfKey())
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.URL.Path == "/redirect" || r.URL.Path == "/redirect/":
if err := tmpls.ExecuteTemplate(w, "auth-redirect.html", nil); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
return
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
}