tailscale/ipn/localapi/localapi.go

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// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package localapi contains the HTTP server handlers for tailscaled's API server.
package localapi
import (
"crypto/rand"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"net/http/httputil"
"net/url"
"reflect"
"runtime"
"strconv"
"strings"
"time"
"inet.af/netaddr"
"tailscale.com/client/tailscale/apitype"
"tailscale.com/ipn"
"tailscale.com/ipn/ipnlocal"
"tailscale.com/ipn/ipnstate"
"tailscale.com/tailcfg"
"tailscale.com/types/logger"
"tailscale.com/util/clientmetric"
"tailscale.com/version"
)
func randHex(n int) string {
b := make([]byte, n)
rand.Read(b)
return hex.EncodeToString(b)
}
func NewHandler(b *ipnlocal.LocalBackend, logf logger.Logf, logID string) *Handler {
return &Handler{b: b, logf: logf, backendLogID: logID}
}
type Handler struct {
// RequiredPassword, if non-empty, forces all HTTP
// requests to have HTTP basic auth with this password.
// It's used by the sandboxed macOS sameuserproof GUI auth mechanism.
RequiredPassword string
// PermitRead is whether read-only HTTP handlers are allowed.
PermitRead bool
// PermitWrite is whether mutating HTTP handlers are allowed.
PermitWrite bool
b *ipnlocal.LocalBackend
logf logger.Logf
backendLogID string
}
func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if h.b == nil {
http.Error(w, "server has no local backend", http.StatusInternalServerError)
return
}
w.Header().Set("Tailscale-Version", version.Long)
if h.RequiredPassword != "" {
_, pass, ok := r.BasicAuth()
if !ok {
http.Error(w, "auth required", http.StatusUnauthorized)
return
}
if pass != h.RequiredPassword {
http.Error(w, "bad password", http.StatusForbidden)
return
}
}
if strings.HasPrefix(r.URL.Path, "/localapi/v0/files/") {
h.serveFiles(w, r)
return
}
if strings.HasPrefix(r.URL.Path, "/localapi/v0/file-put/") {
h.serveFilePut(w, r)
return
}
if strings.HasPrefix(r.URL.Path, "/localapi/v0/cert/") {
h.serveCert(w, r)
return
}
switch r.URL.Path {
case "/localapi/v0/whois":
h.serveWhoIs(w, r)
case "/localapi/v0/goroutines":
h.serveGoroutines(w, r)
case "/localapi/v0/profile":
h.serveProfile(w, r)
case "/localapi/v0/status":
h.serveStatus(w, r)
case "/localapi/v0/logout":
h.serveLogout(w, r)
case "/localapi/v0/prefs":
h.servePrefs(w, r)
case "/localapi/v0/check-ip-forwarding":
h.serveCheckIPForwarding(w, r)
case "/localapi/v0/bugreport":
h.serveBugReport(w, r)
case "/localapi/v0/file-targets":
h.serveFileTargets(w, r)
case "/localapi/v0/set-dns":
h.serveSetDNS(w, r)
case "/localapi/v0/derpmap":
h.serveDERPMap(w, r)
case "/localapi/v0/metrics":
h.serveMetrics(w, r)
case "/localapi/v0/debug":
h.serveDebug(w, r)
case "/":
io.WriteString(w, "tailscaled\n")
default:
http.Error(w, "404 not found", 404)
}
}
func (h *Handler) serveBugReport(w http.ResponseWriter, r *http.Request) {
if !h.PermitRead {
http.Error(w, "bugreport access denied", http.StatusForbidden)
return
}
logMarker := fmt.Sprintf("BUG-%v-%v-%v", h.backendLogID, time.Now().UTC().Format("20060102150405Z"), randHex(8))
h.logf("user bugreport: %s", logMarker)
if note := r.FormValue("note"); len(note) > 0 {
h.logf("user bugreport note: %s", note)
}
w.Header().Set("Content-Type", "text/plain")
fmt.Fprintln(w, logMarker)
}
func (h *Handler) serveWhoIs(w http.ResponseWriter, r *http.Request) {
if !h.PermitRead {
http.Error(w, "whois access denied", http.StatusForbidden)
return
}
b := h.b
var ipp netaddr.IPPort
if v := r.FormValue("addr"); v != "" {
var err error
ipp, err = netaddr.ParseIPPort(v)
if err != nil {
http.Error(w, "invalid 'addr' parameter", 400)
return
}
} else {
http.Error(w, "missing 'addr' parameter", 400)
return
}
n, u, ok := b.WhoIs(ipp)
if !ok {
http.Error(w, "no match for IP:port", 404)
return
}
res := &apitype.WhoIsResponse{
Node: n,
UserProfile: &u,
}
j, err := json.MarshalIndent(res, "", "\t")
if err != nil {
http.Error(w, "JSON encoding error", 500)
return
}
w.Header().Set("Content-Type", "application/json")
w.Write(j)
}
func (h *Handler) serveGoroutines(w http.ResponseWriter, r *http.Request) {
// Require write access out of paranoia that the goroutine dump
// (at least its arguments) might contain something sensitive.
if !h.PermitWrite {
http.Error(w, "goroutine dump access denied", http.StatusForbidden)
return
}
buf := make([]byte, 2<<20)
buf = buf[:runtime.Stack(buf, true)]
w.Header().Set("Content-Type", "text/plain")
w.Write(buf)
}
func (h *Handler) serveMetrics(w http.ResponseWriter, r *http.Request) {
// Require write access out of paranoia that the metrics
// might contain something sensitive.
if !h.PermitWrite {
http.Error(w, "metric access denied", http.StatusForbidden)
return
}
w.Header().Set("Content-Type", "text/plain")
clientmetric.WritePrometheusExpositionFormat(w)
}
func (h *Handler) serveDebug(w http.ResponseWriter, r *http.Request) {
if !h.PermitWrite {
http.Error(w, "debug access denied", http.StatusForbidden)
return
}
if r.Method != "POST" {
http.Error(w, "POST required", http.StatusMethodNotAllowed)
return
}
action := r.FormValue("action")
var err error
switch action {
case "rebind":
err = h.b.DebugRebind()
case "restun":
err = h.b.DebugReSTUN()
case "":
err = fmt.Errorf("missing parameter 'action'")
default:
err = fmt.Errorf("unknown action %q", action)
}
if err != nil {
http.Error(w, err.Error(), 400)
return
}
w.Header().Set("Content-Type", "text/plain")
io.WriteString(w, "done\n")
}
// serveProfileFunc is the implementation of Handler.serveProfile, after auth,
// for platforms where we want to link it in.
var serveProfileFunc func(http.ResponseWriter, *http.Request)
func (h *Handler) serveProfile(w http.ResponseWriter, r *http.Request) {
// Require write access out of paranoia that the profile dump
// might contain something sensitive.
if !h.PermitWrite {
http.Error(w, "profile access denied", http.StatusForbidden)
return
}
if serveProfileFunc == nil {
http.Error(w, "not implemented on this platform", http.StatusServiceUnavailable)
return
}
serveProfileFunc(w, r)
}
func (h *Handler) serveCheckIPForwarding(w http.ResponseWriter, r *http.Request) {
if !h.PermitRead {
http.Error(w, "IP forwarding check access denied", http.StatusForbidden)
return
}
var warning string
if err := h.b.CheckIPForwarding(); err != nil {
warning = err.Error()
}
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(struct {
Warning string
}{
Warning: warning,
})
}
func (h *Handler) serveStatus(w http.ResponseWriter, r *http.Request) {
if !h.PermitRead {
http.Error(w, "status access denied", http.StatusForbidden)
return
}
w.Header().Set("Content-Type", "application/json")
var st *ipnstate.Status
if defBool(r.FormValue("peers"), true) {
st = h.b.Status()
} else {
st = h.b.StatusWithoutPeers()
}
e := json.NewEncoder(w)
e.SetIndent("", "\t")
e.Encode(st)
}
func (h *Handler) serveLogout(w http.ResponseWriter, r *http.Request) {
if !h.PermitWrite {
http.Error(w, "logout access denied", http.StatusForbidden)
return
}
if r.Method != "POST" {
http.Error(w, "want POST", 400)
return
}
err := h.b.LogoutSync(r.Context())
if err == nil {
w.WriteHeader(http.StatusNoContent)
return
}
http.Error(w, err.Error(), 500)
}
func (h *Handler) servePrefs(w http.ResponseWriter, r *http.Request) {
if !h.PermitRead {
http.Error(w, "prefs access denied", http.StatusForbidden)
return
}
var prefs *ipn.Prefs
switch r.Method {
case "PATCH":
if !h.PermitWrite {
http.Error(w, "prefs write access denied", http.StatusForbidden)
return
}
mp := new(ipn.MaskedPrefs)
if err := json.NewDecoder(r.Body).Decode(mp); err != nil {
http.Error(w, err.Error(), 400)
return
}
var err error
prefs, err = h.b.EditPrefs(mp)
if err != nil {
http.Error(w, err.Error(), 400)
return
}
case "GET", "HEAD":
prefs = h.b.Prefs()
default:
http.Error(w, "unsupported method", http.StatusMethodNotAllowed)
return
}
w.Header().Set("Content-Type", "application/json")
e := json.NewEncoder(w)
e.SetIndent("", "\t")
e.Encode(prefs)
}
func (h *Handler) serveFiles(w http.ResponseWriter, r *http.Request) {
if !h.PermitWrite {
http.Error(w, "file access denied", http.StatusForbidden)
return
}
suffix := strings.TrimPrefix(r.URL.EscapedPath(), "/localapi/v0/files/")
if suffix == "" {
if r.Method != "GET" {
http.Error(w, "want GET to list files", 400)
return
}
wfs, err := h.b.WaitingFiles()
if err != nil {
http.Error(w, err.Error(), 500)
return
}
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(wfs)
return
}
name, err := url.PathUnescape(suffix)
if err != nil {
http.Error(w, "bad filename", 400)
return
}
if r.Method == "DELETE" {
if err := h.b.DeleteFile(name); err != nil {
http.Error(w, err.Error(), 500)
return
}
w.WriteHeader(http.StatusNoContent)
return
}
rc, size, err := h.b.OpenFile(name)
if err != nil {
http.Error(w, err.Error(), 500)
return
}
defer rc.Close()
w.Header().Set("Content-Length", fmt.Sprint(size))
io.Copy(w, rc)
}
func writeErrorJSON(w http.ResponseWriter, err error) {
if err == nil {
err = errors.New("unexpected nil error")
}
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(500)
type E struct {
Error string `json:"error"`
}
json.NewEncoder(w).Encode(E{err.Error()})
}
func (h *Handler) serveFileTargets(w http.ResponseWriter, r *http.Request) {
if !h.PermitRead {
http.Error(w, "access denied", http.StatusForbidden)
return
}
if r.Method != "GET" {
http.Error(w, "want GET to list targets", 400)
return
}
fts, err := h.b.FileTargets()
if err != nil {
writeErrorJSON(w, err)
return
}
makeNonNil(&fts)
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(fts)
}
// serveFilePut sends a file to another node.
//
// It's sometimes possible for clients to do this themselves, without
// tailscaled, except in the case of tailscaled running in
// userspace-networking ("netstack") mode, in which case tailscaled
// needs to a do a netstack dial out.
//
// Instead, the CLI also goes through tailscaled so it doesn't need to be
// aware of the network mode in use.
//
// macOS/iOS have always used this localapi method to simplify the GUI
// clients.
//
// The Windows client currently (2021-11-30) uses the peerapi (/v0/put/)
// directly, as the Windows GUI always runs in tun mode anyway.
//
// URL format:
//
// * PUT /localapi/v0/file-put/:stableID/:escaped-filename
func (h *Handler) serveFilePut(w http.ResponseWriter, r *http.Request) {
if !h.PermitWrite {
http.Error(w, "file access denied", http.StatusForbidden)
return
}
if r.Method != "PUT" {
http.Error(w, "want PUT to put file", 400)
return
}
fts, err := h.b.FileTargets()
if err != nil {
http.Error(w, err.Error(), 500)
return
}
upath := strings.TrimPrefix(r.URL.EscapedPath(), "/localapi/v0/file-put/")
slash := strings.Index(upath, "/")
if slash == -1 {
http.Error(w, "bogus URL", 400)
return
}
stableID, filenameEscaped := tailcfg.StableNodeID(upath[:slash]), upath[slash+1:]
var ft *apitype.FileTarget
for _, x := range fts {
if x.Node.StableID == stableID {
ft = x
break
}
}
if ft == nil {
http.Error(w, "node not found", 404)
return
}
dstURL, err := url.Parse(ft.PeerAPIURL)
if err != nil {
http.Error(w, "bogus peer URL", 500)
return
}
outReq, err := http.NewRequestWithContext(r.Context(), "PUT", "http://peer/v0/put/"+filenameEscaped, r.Body)
if err != nil {
http.Error(w, "bogus outreq", 500)
return
}
outReq.ContentLength = r.ContentLength
rp := httputil.NewSingleHostReverseProxy(dstURL)
rp.Transport = h.b.Dialer().PeerAPITransport()
rp.ServeHTTP(w, outReq)
}
func (h *Handler) serveSetDNS(w http.ResponseWriter, r *http.Request) {
if !h.PermitWrite {
http.Error(w, "access denied", http.StatusForbidden)
return
}
if r.Method != "POST" {
http.Error(w, "want POST", 400)
return
}
ctx := r.Context()
err := h.b.SetDNS(ctx, r.FormValue("name"), r.FormValue("value"))
if err != nil {
writeErrorJSON(w, err)
return
}
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(struct{}{})
}
func (h *Handler) serveDERPMap(w http.ResponseWriter, r *http.Request) {
if r.Method != "GET" {
http.Error(w, "want GET", 400)
return
}
w.Header().Set("Content-Type", "application/json")
e := json.NewEncoder(w)
e.SetIndent("", "\t")
e.Encode(h.b.DERPMap())
}
func defBool(a string, def bool) bool {
if a == "" {
return def
}
v, err := strconv.ParseBool(a)
if err != nil {
return def
}
return v
}
// makeNonNil takes a pointer to a Go data structure
// (currently only a slice or a map) and makes sure it's non-nil for
// JSON serialization. (In particular, JavaScript clients usually want
// the field to be defined after they decode the JSON.)
func makeNonNil(ptr interface{}) {
if ptr == nil {
panic("nil interface")
}
rv := reflect.ValueOf(ptr)
if rv.Kind() != reflect.Ptr {
panic(fmt.Sprintf("kind %v, not Ptr", rv.Kind()))
}
if rv.Pointer() == 0 {
panic("nil pointer")
}
rv = rv.Elem()
if rv.Pointer() != 0 {
return
}
switch rv.Type().Kind() {
case reflect.Slice:
rv.Set(reflect.MakeSlice(rv.Type(), 0, 0))
case reflect.Map:
rv.Set(reflect.MakeMap(rv.Type()))
}
}