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package main
import (
"bytes"
"context"
"encoding/base64"
"encoding/json"
"io"
"net/http"
"time"
"github.com/dgrijalva/jwt-go"
"github.com/pquerna/otp/totp"
)
func checkCredentials(username, password, totpPasscode string) bool {
return username == appConfig.User.Nick &&
password == appConfig.User.Password &&
(appConfig.User.TOTP == "" || totp.Validate(totpPasscode, appConfig.User.TOTP))
}
func checkUsernameTOTP(username string, totp bool) bool {
return username == appConfig.User.Nick && totp == (appConfig.User.TOTP != "")
}
func checkAppPasswords(username, password string) bool {
for _, apw := range appConfig.User.AppPasswords {
if apw.Username == username && apw.Password == password {
return true
}
}
return false
}
func jwtKey() []byte {
return []byte(appConfig.Server.JWTSecret)
}
func authMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Check if already logged in
if loggedIn, ok := r.Context().Value(loggedInKey).(bool); ok && loggedIn {
next.ServeHTTP(w, r)
return
}
// 1. Check BasicAuth (just for app passwords)
if username, password, ok := r.BasicAuth(); ok && checkAppPasswords(username, password) {
next.ServeHTTP(w, r)
return
}
// 2. Check JWT
if checkAuthToken(r) {
next.ServeHTTP(w, r)
return
}
// 3. Show login form
w.Header().Set("Cache-Control", "no-store,max-age=0")
h, _ := json.Marshal(r.Header.Clone())
b, _ := io.ReadAll(io.LimitReader(r.Body, 2000000)) // Only allow 20 Megabyte
_ = r.Body.Close()
if len(b) == 0 {
// Maybe it's a form
_ = r.ParseForm()
b = []byte(r.PostForm.Encode())
}
render(w, r, templateLogin, &renderData{
Data: map[string]interface{}{
"loginmethod": r.Method,
"loginheaders": base64.StdEncoding.EncodeToString(h),
"loginbody": base64.StdEncoding.EncodeToString(b),
"totp": appConfig.User.TOTP != "",
},
})
})
}
func checkAuthToken(r *http.Request) bool {
if tokenCookie, err := r.Cookie("token"); err == nil {
claims := &authClaims{}
if tkn, err := jwt.ParseWithClaims(tokenCookie.Value, claims, func(t *jwt.Token) (interface{}, error) {
return jwtKey(), nil
}); err == nil && tkn.Valid &&
claims.TokenType == "login" &&
checkUsernameTOTP(claims.Username, claims.TOTP) {
return true
}
}
return false
}
const loggedInKey requestContextKey = "loggedIn"
func checkLoggedIn(next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
if checkAuthToken(r) {
next.ServeHTTP(rw, r.WithContext(context.WithValue(r.Context(), loggedInKey, true)))
return
}
next.ServeHTTP(rw, r)
})
}
func checkIsLogin(next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
if !checkLogin(rw, r) {
next.ServeHTTP(rw, r)
}
})
}
func checkLogin(w http.ResponseWriter, r *http.Request) bool {
if r.Method != http.MethodPost {
return false
}
if r.Header.Get(contentType) != contentTypeWWWForm {
return false
}
if r.FormValue("loginaction") != "login" {
return false
}
// Check credential
if !checkCredentials(r.FormValue("username"), r.FormValue("password"), r.FormValue("token")) {
serveError(w, r, "Incorrect credentials", http.StatusUnauthorized)
return true
}
// Prepare original request
loginbody, _ := base64.StdEncoding.DecodeString(r.FormValue("loginbody"))
req, _ := http.NewRequest(r.FormValue("loginmethod"), r.RequestURI, bytes.NewReader(loginbody))
// Copy original headers
loginheaders, _ := base64.StdEncoding.DecodeString(r.FormValue("loginheaders"))
var headers http.Header
_ = json.Unmarshal(loginheaders, &headers)
for k, v := range headers {
req.Header[k] = v
}
// Cookie
tokenCookie, err := createTokenCookie()
if err != nil {
serveError(w, r, err.Error(), http.StatusInternalServerError)
return true
}
req.AddCookie(tokenCookie)
http.SetCookie(w, tokenCookie)
// Serve original request
d.ServeHTTP(w, req)
return true
}
type authClaims struct {
*jwt.StandardClaims
TokenType string
Username string
TOTP bool
}
func createTokenCookie() (*http.Cookie, error) {
expiration := time.Now().Add(7 * 24 * time.Hour)
tokenString, err := jwt.NewWithClaims(jwt.SigningMethodHS256, &authClaims{
&jwt.StandardClaims{ExpiresAt: expiration.Unix()},
"login",
appConfig.User.Nick,
appConfig.User.TOTP != "",
}).SignedString(jwtKey())
if err != nil {
return nil, err
}
return &http.Cookie{
Name: "token",
Value: tokenString,
Expires: expiration,
Secure: httpsConfigured(),
HttpOnly: true,
SameSite: http.SameSiteLaxMode,
}, nil
}
// Need to set auth middleware!
func serveLogin(w http.ResponseWriter, r *http.Request) {
http.Redirect(w, r, "/", http.StatusFound)
}
func serveLogout(w http.ResponseWriter, r *http.Request) {
http.SetCookie(w, &http.Cookie{
Name: "token",
MaxAge: -1,
Secure: httpsConfigured(),
HttpOnly: true,
SameSite: http.SameSiteLaxMode,
})
http.Redirect(w, r, "/", http.StatusFound)
}