Files
cc-backend/internal/auth/jwtSession.go
Jan Eitzinger 6d86690c76 Fix critical issues from follow-up security audit
A second-pass audit surfaced three severe issues missed by the previous
review, each a sibling code path of a bug class that was only partially
fixed before:

- auth: JWT session login (jwtSession.go) registered its authenticator
  even when CROSS_LOGIN_JWT_HS512_KEY was unset, leaving an empty HMAC
  key. golang-jwt verifies any HS256/HS512 signature against an empty
  key, allowing unauthenticated admin token forgery. Init() now refuses
  to register without a key, with a defense-in-depth empty-key guard in
  the keyfunc.

- repository: metric names from GraphQL ([String!]) were interpolated
  raw into json_extract(footprint, "$.<name>") SQL. SQLite parses
  double-quoted strings as literals, enabling SQL injection by any
  authenticated user. Validate metric names against ^[a-zA-Z0-9_]+$ in
  jobsMetricStatisticsHistogram and buildFloatJSONCondition.

- metricstore: cluster/host line-protocol tags flowed unvalidated into
  path.Join(RootDir, cluster, host) for checkpoint/WAL files, allowing
  arbitrary file write outside the checkpoint root via NATS
  (unauthenticated) or POST /api/write. Reject path-traversal sequences
  in DecodeLine before the tags become path components.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Entire-Checkpoint: b57246993ec1
2026-06-04 19:07:20 +02:00

104 lines
3.0 KiB
Go

// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
// All rights reserved. This file is part of cc-backend.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package auth
import (
"encoding/base64"
"errors"
"fmt"
"net/http"
"os"
"strings"
cclog "github.com/ClusterCockpit/cc-lib/v2/ccLogger"
"github.com/ClusterCockpit/cc-lib/v2/schema"
"github.com/golang-jwt/jwt/v5"
)
type JWTSessionAuthenticator struct {
loginTokenKey []byte // HS256 key
}
var _ Authenticator = (*JWTSessionAuthenticator)(nil)
func (ja *JWTSessionAuthenticator) Init() error {
pubKey := os.Getenv("CROSS_LOGIN_JWT_HS512_KEY")
if pubKey == "" {
// Without a configured key the HMAC verification below would run against
// an empty key, which lets anyone forge a valid token. Refuse to register
// the authenticator in that case so JWT session login is simply disabled.
return errors.New("CROSS_LOGIN_JWT_HS512_KEY not set: JWT session login disabled")
}
bytes, err := base64.StdEncoding.DecodeString(pubKey)
if err != nil {
cclog.Warn("Could not decode cross login JWT HS512 key")
return err
}
ja.loginTokenKey = bytes
cclog.Info("JWT Session authenticator successfully registered")
return nil
}
func (ja *JWTSessionAuthenticator) CanLogin(
user *schema.User,
username string,
rw http.ResponseWriter,
r *http.Request,
) (*schema.User, bool) {
return user, r.Header.Get("Authorization") != "" ||
r.URL.Query().Get("login-token") != ""
}
func (ja *JWTSessionAuthenticator) Login(
user *schema.User,
rw http.ResponseWriter,
r *http.Request,
) (*schema.User, error) {
rawtoken := strings.TrimPrefix(r.Header.Get("Authorization"), "Bearer ")
if rawtoken == "" {
rawtoken = r.URL.Query().Get("login-token")
}
token, err := jwt.Parse(rawtoken, func(t *jwt.Token) (any, error) {
if t.Method == jwt.SigningMethodHS256 || t.Method == jwt.SigningMethodHS512 {
// Defense in depth: an empty key would verify any HMAC signature.
// Init() already refuses to register without a key, so this should
// never trigger, but guard explicitly rather than trust the chain.
if len(ja.loginTokenKey) == 0 {
return nil, errors.New("HS login key not configured")
}
return ja.loginTokenKey, nil
}
return nil, fmt.Errorf("unkown signing method for login token: %s (known: HS256, HS512, EdDSA)", t.Method.Alg())
})
if err != nil {
cclog.Warn("Error while parsing jwt token")
return nil, err
}
if !token.Valid {
cclog.Warn("jwt token claims are not valid")
return nil, errors.New("jwt token claims are not valid")
}
claims := token.Claims.(jwt.MapClaims)
// Use shared helper to get user from JWT claims
user, err = getUserFromJWT(claims, Keys.JwtConfig.ValidateUser, schema.AuthSession, schema.AuthViaToken)
if err != nil {
return nil, err
}
// Sync or update user if configured
if !Keys.JwtConfig.ValidateUser && (Keys.JwtConfig.SyncUserOnLogin || Keys.JwtConfig.UpdateUserOnLogin) {
handleTokenUser(user)
}
return user, nil
}