AUTH-2235 GetTokenIfExists now parses JWT payload for json expiry field to detect if the cached access token is expired

cmd/cloudflared/token/token.go

@@ -2,12 +2,14 @@ package token
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"net/url"
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/config"
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/path"
@@ -34,6 +36,21 @@ type signalHandler struct {
 	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...)
@@ -147,7 +164,7 @@ func FetchToken(appURL *url.URL) (string, error) {
 	return string(token), nil
 }
 
-// GetTokenIfExists will return the token from local storage if it exists
+// GetTokenIfExists will return the token from local storage if it exists and not expired
 func GetTokenIfExists(url *url.URL) (string, error) {
 	path, err := path.GenerateFilePathFromURL(url, keyName)
 	if err != nil {
@@ -162,6 +179,17 @@ func GetTokenIfExists(url *url.URL) (string, error) {
 		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
 }