cloudflared-mirror/cmd/cloudflared/token/token.go

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package token
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"net/url"
"os"
"os/signal"
"syscall"
"time"
"github.com/cloudflare/cloudflared/cmd/cloudflared/config"
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"github.com/cloudflare/cloudflared/cmd/cloudflared/path"
"github.com/cloudflare/cloudflared/cmd/cloudflared/transfer"
"github.com/cloudflare/cloudflared/logger"
"github.com/cloudflare/cloudflared/origin"
"github.com/coreos/go-oidc/jose"
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)
const (
keyName = "token"
)
type lock struct {
lockFilePath string
backoff *origin.BackoffHandler
sigHandler *signalHandler
}
type signalHandler struct {
sigChannel chan os.Signal
signals []os.Signal
}
type jwtPayload struct {
Aud []string `json:"aud"`
Email string `json:"email"`
Exp int `json:"exp"`
Iat int `json:"iat"`
Nbf int `json:"nbf"`
Iss string `json:"iss"`
Type string `json:"type"`
Subt string `json:"sub"`
}
func (p jwtPayload) isExpired() bool {
return int(time.Now().Unix()) > p.Exp
}
func (s *signalHandler) register(handler func()) {
s.sigChannel = make(chan os.Signal, 1)
signal.Notify(s.sigChannel, s.signals...)
go func(s *signalHandler) {
for range s.sigChannel {
handler()
}
}(s)
}
func (s *signalHandler) deregister() {
signal.Stop(s.sigChannel)
close(s.sigChannel)
}
func errDeleteTokenFailed(lockFilePath string) error {
return fmt.Errorf("failed to acquire a new Access token. Please try to delete %s", lockFilePath)
}
// newLock will get a new file lock
func newLock(path string) *lock {
lockPath := path + ".lock"
return &lock{
lockFilePath: lockPath,
backoff: &origin.BackoffHandler{MaxRetries: 7},
sigHandler: &signalHandler{
signals: []os.Signal{syscall.SIGINT, syscall.SIGTERM},
},
}
}
func (l *lock) Acquire() error {
// Intercept SIGINT and SIGTERM to release lock before exiting
l.sigHandler.register(func() {
l.deleteLockFile()
os.Exit(0)
})
// Check for a path.lock file
// if the lock file exists; start polling
// if not, create the lock file and go through the normal flow.
// See AUTH-1736 for the reason why we do all this
for isTokenLocked(l.lockFilePath) {
if l.backoff.Backoff(context.Background()) {
continue
}
if err := l.deleteLockFile(); err != nil {
return err
}
}
// Create a lock file so other processes won't also try to get the token at
// the same time
if err := ioutil.WriteFile(l.lockFilePath, []byte{}, 0600); err != nil {
return err
}
return nil
}
func (l *lock) deleteLockFile() error {
if err := os.Remove(l.lockFilePath); err != nil && !os.IsNotExist(err) {
return errDeleteTokenFailed(l.lockFilePath)
}
return nil
}
func (l *lock) Release() error {
defer l.sigHandler.deregister()
return l.deleteLockFile()
}
// isTokenLocked checks to see if there is another process attempting to get the token already
func isTokenLocked(lockFilePath string) bool {
exists, err := config.FileExists(lockFilePath)
return exists && err == nil
}
// FetchTokenWithRedirect will either load a stored token or generate a new one
// it appends the full url as the redirect URL to the access cli request if opening the browser
func FetchTokenWithRedirect(appURL *url.URL, logger logger.Service) (string, error) {
return getToken(appURL, false, logger)
}
// FetchToken will either load a stored token or generate a new one
// it appends the host of the appURL as the redirect URL to the access cli request if opening the browser
func FetchToken(appURL *url.URL, logger logger.Service) (string, error) {
return getToken(appURL, true, logger)
}
// getToken will either load a stored token or generate a new one
func getToken(appURL *url.URL, useHostOnly bool, logger logger.Service) (string, error) {
if token, err := GetTokenIfExists(appURL); token != "" && err == nil {
return token, nil
}
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path, err := path.GenerateFilePathFromURL(appURL, keyName)
if err != nil {
return "", err
}
fileLock := newLock(path)
err = fileLock.Acquire()
if err != nil {
return "", err
}
defer fileLock.Release()
// check to see if another process has gotten a token while we waited for the lock
if token, err := GetTokenIfExists(appURL); token != "" && err == nil {
return token, nil
}
// this weird parameter is the resource name (token) and the key/value
// we want to send to the transfer service. the key is token and the value
// is blank (basically just the id generated in the transfer service)
token, err := transfer.Run(appURL, keyName, keyName, "", path, true, useHostOnly, logger)
if err != nil {
return "", err
}
return string(token), nil
}
// GetTokenIfExists will return the token from local storage if it exists and not expired
func GetTokenIfExists(url *url.URL) (string, error) {
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path, err := path.GenerateFilePathFromURL(url, keyName)
if err != nil {
return "", err
}
content, err := ioutil.ReadFile(path)
if err != nil {
return "", err
}
token, err := jose.ParseJWT(string(content))
if err != nil {
return "", err
}
var payload jwtPayload
err = json.Unmarshal(token.Payload, &payload)
if err != nil {
return "", err
}
if payload.isExpired() {
err := os.Remove(path)
return "", err
}
return token.Encode(), nil
}
// RemoveTokenIfExists removes the a token from local storage if it exists
func RemoveTokenIfExists(url *url.URL) error {
path, err := path.GenerateFilePathFromURL(url, keyName)
if err != nil {
return err
}
if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
return err
}
return nil
}