cc-backend/internal/auth/jwtCookieSession.go

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// Copyright (C) 2023 NHR@FAU, University Erlangen-Nuremberg.
// All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package auth
import (
"crypto/ed25519"
"encoding/base64"
"errors"
"net/http"
"os"
"github.com/ClusterCockpit/cc-backend/pkg/log"
"github.com/ClusterCockpit/cc-backend/pkg/schema"
"github.com/golang-jwt/jwt/v4"
)
type JWTCookieSessionAuthenticator struct {
auth *Authentication
publicKey ed25519.PublicKey
privateKey ed25519.PrivateKey
publicKeyCrossLogin ed25519.PublicKey // For accepting externally generated JWTs
config *schema.JWTAuthConfig
}
var _ Authenticator = (*JWTCookieSessionAuthenticator)(nil)
func (ja *JWTCookieSessionAuthenticator) Init(auth *Authentication, conf interface{}) error {
ja.auth = auth
ja.config = conf.(*schema.JWTAuthConfig)
pubKey, privKey := os.Getenv("JWT_PUBLIC_KEY"), os.Getenv("JWT_PRIVATE_KEY")
if pubKey == "" || privKey == "" {
log.Warn("environment variables 'JWT_PUBLIC_KEY' or 'JWT_PRIVATE_KEY' not set (token based authentication will not work)")
return errors.New("environment variables 'JWT_PUBLIC_KEY' or 'JWT_PRIVATE_KEY' not set (token based authentication will not work)")
} else {
bytes, err := base64.StdEncoding.DecodeString(pubKey)
if err != nil {
log.Warn("Could not decode JWT public key")
return err
}
ja.publicKey = ed25519.PublicKey(bytes)
bytes, err = base64.StdEncoding.DecodeString(privKey)
if err != nil {
log.Warn("Could not decode JWT private key")
return err
}
ja.privateKey = ed25519.PrivateKey(bytes)
}
// Look for external public keys
pubKeyCrossLogin, keyFound := os.LookupEnv("CROSS_LOGIN_JWT_PUBLIC_KEY")
if keyFound && pubKeyCrossLogin != "" {
bytes, err := base64.StdEncoding.DecodeString(pubKeyCrossLogin)
if err != nil {
log.Warn("Could not decode cross login JWT public key")
return err
}
ja.publicKeyCrossLogin = ed25519.PublicKey(bytes)
} else {
ja.publicKeyCrossLogin = nil
log.Debug("environment variable 'CROSS_LOGIN_JWT_PUBLIC_KEY' not set (cross login token based authentication will not work)")
return errors.New("environment variable 'CROSS_LOGIN_JWT_PUBLIC_KEY' not set (cross login token based authentication will not work)")
}
// Warn if other necessary settings are not configured
if ja.config != nil {
if ja.config.CookieName == "" {
log.Warn("cookieName for JWTs not configured (cross login via JWT cookie will fail)")
return errors.New("cookieName for JWTs not configured (cross login via JWT cookie will fail)")
}
if !ja.config.ForceJWTValidationViaDatabase {
log.Warn("forceJWTValidationViaDatabase not set to true: CC will accept users and roles defined in JWTs regardless of its own database!")
}
if ja.config.TrustedExternalIssuer == "" {
log.Warn("trustedExternalIssuer for JWTs not configured (cross login via JWT cookie will fail)")
return errors.New("trustedExternalIssuer for JWTs not configured (cross login via JWT cookie will fail)")
}
} else {
log.Warn("config for JWTs not configured (cross login via JWT cookie will fail)")
return errors.New("config for JWTs not configured (cross login via JWT cookie will fail)")
}
return nil
}
func (ja *JWTCookieSessionAuthenticator) CanLogin(
user *User,
username string,
rw http.ResponseWriter,
r *http.Request) bool {
cookieName := ""
if ja.config != nil && ja.config.CookieName != "" {
cookieName = ja.config.CookieName
}
// Try to read the JWT cookie
if cookieName != "" {
jwtCookie, err := r.Cookie(cookieName)
if err == nil && jwtCookie.Value != "" {
return true
}
}
return false
}
func (ja *JWTCookieSessionAuthenticator) Login(
user *User,
rw http.ResponseWriter,
r *http.Request) (*User, error) {
jwtCookie, err := r.Cookie(ja.config.CookieName)
var rawtoken string
if err == nil && jwtCookie.Value != "" {
rawtoken = jwtCookie.Value
}
token, err := jwt.Parse(rawtoken, func(t *jwt.Token) (interface{}, error) {
if t.Method != jwt.SigningMethodEdDSA {
return nil, errors.New("only Ed25519/EdDSA supported")
}
unvalidatedIssuer, success := t.Claims.(jwt.MapClaims)["iss"].(string)
if success && unvalidatedIssuer == ja.config.TrustedExternalIssuer {
// The (unvalidated) issuer seems to be the expected one,
// use public cross login key from config
return ja.publicKeyCrossLogin, nil
}
// No cross login key configured or issuer not expected
// Try own key
return ja.publicKey, nil
})
if err != nil {
log.Warn("error while parsing token")
return nil, err
}
// Check token validity and extract paypload
if err := token.Claims.Valid(); err != nil {
log.Warn("jwt token claims are not valid")
return nil, err
}
claims := token.Claims.(jwt.MapClaims)
sub, _ := claims["sub"].(string)
var name string
if val, ok := claims["name"]; ok {
name, _ = val.(string)
}
var roles []string
if ja.config.ForceJWTValidationViaDatabase {
// Deny any logins for unknown usernames
if user == nil {
log.Warn("Could not find user from JWT in internal database.")
return nil, errors.New("unknown user")
}
// Take user roles from database instead of trusting the JWT
roles = user.Roles
} else {
// Extract roles from JWT (if present)
if rawroles, ok := claims["roles"].([]interface{}); ok {
for _, rr := range rawroles {
if r, ok := rr.(string); ok {
roles = append(roles, r)
}
}
}
}
// (Ask browser to) Delete JWT cookie
deletedCookie := &http.Cookie{
Name: ja.config.CookieName,
Value: "",
Path: "/",
MaxAge: -1,
HttpOnly: true,
}
http.SetCookie(rw, deletedCookie)
if user == nil {
user = &User{
Username: sub,
Name: name,
Roles: roles,
AuthType: AuthSession,
AuthSource: AuthViaToken,
}
}
return user, nil
}