package home import ( "crypto/rand" "encoding/binary" "encoding/hex" "encoding/json" "fmt" "net" "net/http" "path" "strconv" "strings" "sync" "time" "github.com/AdguardTeam/AdGuardHome/internal/aghhttp" "github.com/AdguardTeam/golibs/errors" "github.com/AdguardTeam/golibs/log" "github.com/AdguardTeam/golibs/netutil" "github.com/AdguardTeam/golibs/timeutil" "go.etcd.io/bbolt" "golang.org/x/crypto/bcrypt" ) // cookieTTL is the time-to-live of the session cookie. const cookieTTL = 365 * timeutil.Day // sessionCookieName is the name of the session cookie. const sessionCookieName = "agh_session" // sessionTokenSize is the length of session token in bytes. const sessionTokenSize = 16 type session struct { userName string // expire is the expiration time, in seconds. expire uint32 } func (s *session) serialize() []byte { const ( expireLen = 4 nameLen = 2 ) data := make([]byte, expireLen+nameLen+len(s.userName)) binary.BigEndian.PutUint32(data[0:4], s.expire) binary.BigEndian.PutUint16(data[4:6], uint16(len(s.userName))) copy(data[6:], []byte(s.userName)) return data } func (s *session) deserialize(data []byte) bool { if len(data) < 4+2 { return false } s.expire = binary.BigEndian.Uint32(data[0:4]) nameLen := binary.BigEndian.Uint16(data[4:6]) data = data[6:] if len(data) < int(nameLen) { return false } s.userName = string(data) return true } // Auth - global object type Auth struct { db *bbolt.DB raleLimiter *authRateLimiter sessions map[string]*session users []webUser lock sync.Mutex sessionTTL uint32 } // webUser represents a user of the Web UI. type webUser struct { Name string `yaml:"name"` PasswordHash string `yaml:"password"` } // InitAuth - create a global object func InitAuth(dbFilename string, users []webUser, sessionTTL uint32, rateLimiter *authRateLimiter) *Auth { log.Info("Initializing auth module: %s", dbFilename) a := &Auth{ sessionTTL: sessionTTL, raleLimiter: rateLimiter, sessions: make(map[string]*session), users: users, } var err error a.db, err = bbolt.Open(dbFilename, 0o644, nil) if err != nil { log.Error("auth: open DB: %s: %s", dbFilename, err) if err.Error() == "invalid argument" { log.Error("AdGuard Home cannot be initialized due to an incompatible file system.\nPlease read the explanation here: https://github.com/AdguardTeam/AdGuardHome/wiki/Getting-Started#limitations") } return nil } a.loadSessions() log.Info("auth: initialized. users:%d sessions:%d", len(a.users), len(a.sessions)) return a } // Close - close module func (a *Auth) Close() { _ = a.db.Close() } func bucketName() []byte { return []byte("sessions-2") } // load sessions from file, remove expired sessions func (a *Auth) loadSessions() { tx, err := a.db.Begin(true) if err != nil { log.Error("auth: bbolt.Begin: %s", err) return } defer func() { _ = tx.Rollback() }() bkt := tx.Bucket(bucketName()) if bkt == nil { return } removed := 0 if tx.Bucket([]byte("sessions")) != nil { _ = tx.DeleteBucket([]byte("sessions")) removed = 1 } now := uint32(time.Now().UTC().Unix()) forEach := func(k, v []byte) error { s := session{} if !s.deserialize(v) || s.expire <= now { err = bkt.Delete(k) if err != nil { log.Error("auth: bbolt.Delete: %s", err) } else { removed++ } return nil } a.sessions[hex.EncodeToString(k)] = &s return nil } _ = bkt.ForEach(forEach) if removed != 0 { err = tx.Commit() if err != nil { log.Error("bolt.Commit(): %s", err) } } log.Debug("auth: loaded %d sessions from DB (removed %d expired)", len(a.sessions), removed) } // store session data in file func (a *Auth) addSession(data []byte, s *session) { name := hex.EncodeToString(data) a.lock.Lock() a.sessions[name] = s a.lock.Unlock() if a.storeSession(data, s) { log.Debug("auth: created session %s: expire=%d", name, s.expire) } } // store session data in file func (a *Auth) storeSession(data []byte, s *session) bool { tx, err := a.db.Begin(true) if err != nil { log.Error("auth: bbolt.Begin: %s", err) return false } defer func() { _ = tx.Rollback() }() bkt, err := tx.CreateBucketIfNotExists(bucketName()) if err != nil { log.Error("auth: bbolt.CreateBucketIfNotExists: %s", err) return false } err = bkt.Put(data, s.serialize()) if err != nil { log.Error("auth: bbolt.Put: %s", err) return false } err = tx.Commit() if err != nil { log.Error("auth: bbolt.Commit: %s", err) return false } return true } // remove session from file func (a *Auth) removeSession(sess []byte) { tx, err := a.db.Begin(true) if err != nil { log.Error("auth: bbolt.Begin: %s", err) return } defer func() { _ = tx.Rollback() }() bkt := tx.Bucket(bucketName()) if bkt == nil { log.Error("auth: bbolt.Bucket") return } err = bkt.Delete(sess) if err != nil { log.Error("auth: bbolt.Put: %s", err) return } err = tx.Commit() if err != nil { log.Error("auth: bbolt.Commit: %s", err) return } log.Debug("auth: removed session from DB") } // checkSessionResult is the result of checking a session. type checkSessionResult int // checkSessionResult constants. const ( checkSessionOK checkSessionResult = 0 checkSessionNotFound checkSessionResult = -1 checkSessionExpired checkSessionResult = 1 ) // checkSession checks if the session is valid. func (a *Auth) checkSession(sess string) (res checkSessionResult) { now := uint32(time.Now().UTC().Unix()) update := false a.lock.Lock() defer a.lock.Unlock() s, ok := a.sessions[sess] if !ok { return checkSessionNotFound } if s.expire <= now { delete(a.sessions, sess) key, _ := hex.DecodeString(sess) a.removeSession(key) return checkSessionExpired } newExpire := now + a.sessionTTL if s.expire/(24*60*60) != newExpire/(24*60*60) { // update expiration time once a day update = true s.expire = newExpire } if update { key, _ := hex.DecodeString(sess) if a.storeSession(key, s) { log.Debug("auth: updated session %s: expire=%d", sess, s.expire) } } return checkSessionOK } // RemoveSession - remove session func (a *Auth) RemoveSession(sess string) { key, _ := hex.DecodeString(sess) a.lock.Lock() delete(a.sessions, sess) a.lock.Unlock() a.removeSession(key) } type loginJSON struct { Name string `json:"name"` Password string `json:"password"` } // newSessionToken returns cryptographically secure randomly generated slice of // bytes of sessionTokenSize length. // // TODO(e.burkov): Think about using byte array instead of byte slice. func newSessionToken() (data []byte, err error) { randData := make([]byte, sessionTokenSize) _, err = rand.Read(randData) if err != nil { return nil, err } return randData, nil } // newCookie creates a new authentication cookie. func (a *Auth) newCookie(req loginJSON, addr string) (c *http.Cookie, err error) { rateLimiter := a.raleLimiter u, ok := a.findUser(req.Name, req.Password) if !ok { if rateLimiter != nil { rateLimiter.inc(addr) } return nil, errors.Error("invalid username or password") } if rateLimiter != nil { rateLimiter.remove(addr) } sess, err := newSessionToken() if err != nil { return nil, fmt.Errorf("generating token: %w", err) } now := time.Now().UTC() a.addSession(sess, &session{ userName: u.Name, expire: uint32(now.Unix()) + a.sessionTTL, }) return &http.Cookie{ Name: sessionCookieName, Value: hex.EncodeToString(sess), Path: "/", Expires: now.Add(cookieTTL), HttpOnly: true, SameSite: http.SameSiteLaxMode, }, nil } // realIP extracts the real IP address of the client from an HTTP request using // the known HTTP headers. // // TODO(a.garipov): Currently, this is basically a copy of a similar function in // module dnsproxy. This should really become a part of module golibs and be // replaced both here and there. Or be replaced in both places by // a well-maintained third-party module. // // TODO(a.garipov): Support header Forwarded from RFC 7329. func realIP(r *http.Request) (ip net.IP, err error) { proxyHeaders := []string{ "CF-Connecting-IP", "True-Client-IP", "X-Real-IP", } for _, h := range proxyHeaders { v := r.Header.Get(h) ip = net.ParseIP(v) if ip != nil { return ip, nil } } // If none of the above yielded any results, get the leftmost IP address // from the X-Forwarded-For header. s := r.Header.Get("X-Forwarded-For") ipStrs := strings.SplitN(s, ", ", 2) ip = net.ParseIP(ipStrs[0]) if ip != nil { return ip, nil } // When everything else fails, just return the remote address as understood // by the stdlib. ipStr, err := netutil.SplitHost(r.RemoteAddr) if err != nil { return nil, fmt.Errorf("getting ip from client addr: %w", err) } return net.ParseIP(ipStr), nil } func handleLogin(w http.ResponseWriter, r *http.Request) { req := loginJSON{} err := json.NewDecoder(r.Body).Decode(&req) if err != nil { aghhttp.Error(r, w, http.StatusBadRequest, "json decode: %s", err) return } var remoteAddr string // realIP cannot be used here without taking TrustedProxies into account due // to security issues. // // See https://github.com/AdguardTeam/AdGuardHome/issues/2799. // // TODO(e.burkov): Use realIP when the issue will be fixed. if remoteAddr, err = netutil.SplitHost(r.RemoteAddr); err != nil { aghhttp.Error(r, w, http.StatusBadRequest, "auth: getting remote address: %s", err) return } if rateLimiter := Context.auth.raleLimiter; rateLimiter != nil { if left := rateLimiter.check(remoteAddr); left > 0 { w.Header().Set("Retry-After", strconv.Itoa(int(left.Seconds()))) aghhttp.Error(r, w, http.StatusTooManyRequests, "auth: blocked for %s", left) return } } cookie, err := Context.auth.newCookie(req, remoteAddr) if err != nil { aghhttp.Error(r, w, http.StatusForbidden, "%s", err) return } // Use realIP here, since this IP address is only used for logging. ip, err := realIP(r) if err != nil { log.Error("auth: getting real ip from request: %s", err) } else if ip == nil { // Technically shouldn't happen. log.Error("auth: unknown ip") } log.Info("auth: user %q successfully logged in from ip %v", req.Name, ip) http.SetCookie(w, cookie) h := w.Header() h.Set("Cache-Control", "no-store, no-cache, must-revalidate, proxy-revalidate") h.Set("Pragma", "no-cache") h.Set("Expires", "0") aghhttp.OK(w) } func handleLogout(w http.ResponseWriter, r *http.Request) { respHdr := w.Header() c, err := r.Cookie(sessionCookieName) if err != nil { // The only error that is returned from r.Cookie is [http.ErrNoCookie]. // The user is already logged out. respHdr.Set("Location", "/login.html") w.WriteHeader(http.StatusFound) return } Context.auth.RemoveSession(c.Value) c = &http.Cookie{ Name: sessionCookieName, Value: "", Path: "/", Expires: time.Unix(0, 0), HttpOnly: true, SameSite: http.SameSiteLaxMode, } respHdr.Set("Location", "/login.html") respHdr.Set("Set-Cookie", c.String()) w.WriteHeader(http.StatusFound) } // RegisterAuthHandlers - register handlers func RegisterAuthHandlers() { Context.mux.Handle("/control/login", postInstallHandler(ensureHandler(http.MethodPost, handleLogin))) httpRegister(http.MethodGet, "/control/logout", handleLogout) } // optionalAuthThird return true if user should authenticate first. func optionalAuthThird(w http.ResponseWriter, r *http.Request) (mustAuth bool) { if glProcessCookie(r) { log.Debug("auth: authentication is handled by GL-Inet submodule") return false } // redirect to login page if not authenticated isAuthenticated := false cookie, err := r.Cookie(sessionCookieName) if err != nil { // The only error that is returned from r.Cookie is [http.ErrNoCookie]. // Check Basic authentication. user, pass, hasBasic := r.BasicAuth() if hasBasic { _, isAuthenticated = Context.auth.findUser(user, pass) if !isAuthenticated { log.Info("auth: invalid Basic Authorization value") } } } else { res := Context.auth.checkSession(cookie.Value) isAuthenticated = res == checkSessionOK if !isAuthenticated { log.Debug("auth: invalid cookie value: %s", cookie) } } if isAuthenticated { return false } if p := r.URL.Path; p == "/" || p == "/index.html" { if glProcessRedirect(w, r) { log.Debug("auth: redirected to login page by GL-Inet submodule") } else { log.Debug("auth: redirected to login page") w.Header().Set("Location", "/login.html") w.WriteHeader(http.StatusFound) } } else { log.Debug("auth: responded with forbidden to %s %s", r.Method, p) w.WriteHeader(http.StatusForbidden) _, _ = w.Write([]byte("Forbidden")) } return true } // TODO(a.garipov): Use [http.Handler] consistently everywhere throughout the // project. func optionalAuth( h func(http.ResponseWriter, *http.Request), ) (wrapped func(http.ResponseWriter, *http.Request)) { return func(w http.ResponseWriter, r *http.Request) { p := r.URL.Path authRequired := Context.auth != nil && Context.auth.AuthRequired() if p == "/login.html" { cookie, err := r.Cookie(sessionCookieName) if authRequired && err == nil { // Redirect to the dashboard if already authenticated. res := Context.auth.checkSession(cookie.Value) if res == checkSessionOK { w.Header().Set("Location", "/") w.WriteHeader(http.StatusFound) return } log.Debug("auth: invalid cookie value: %s", cookie) } } else if isPublicResource(p) { // Process as usual, no additional auth requirements. } else if authRequired { if optionalAuthThird(w, r) { return } } h(w, r) } } // isPublicResource returns true if p is a path to a public resource. func isPublicResource(p string) (ok bool) { isAsset, err := path.Match("/assets/*", p) if err != nil { // The only error that is returned from path.Match is // [path.ErrBadPattern]. This is a programmer error. panic(fmt.Errorf("bad asset pattern: %w", err)) } isLogin, err := path.Match("/login.*", p) if err != nil { // Same as above. panic(fmt.Errorf("bad login pattern: %w", err)) } return isAsset || isLogin } type authHandler struct { handler http.Handler } func (a *authHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { optionalAuth(a.handler.ServeHTTP)(w, r) } func optionalAuthHandler(handler http.Handler) http.Handler { return &authHandler{handler} } // UserAdd - add new user func (a *Auth) UserAdd(u *webUser, password string) { if len(password) == 0 { return } hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost) if err != nil { log.Error("bcrypt.GenerateFromPassword: %s", err) return } u.PasswordHash = string(hash) a.lock.Lock() a.users = append(a.users, *u) a.lock.Unlock() log.Debug("auth: added user: %s", u.Name) } // findUser returns a user if there is one. func (a *Auth) findUser(login, password string) (u webUser, ok bool) { a.lock.Lock() defer a.lock.Unlock() for _, u = range a.users { if u.Name == login && bcrypt.CompareHashAndPassword([]byte(u.PasswordHash), []byte(password)) == nil { return u, true } } return webUser{}, false } // getCurrentUser returns the current user. It returns an empty User if the // user is not found. func (a *Auth) getCurrentUser(r *http.Request) (u webUser) { cookie, err := r.Cookie(sessionCookieName) if err != nil { // There's no Cookie, check Basic authentication. user, pass, ok := r.BasicAuth() if ok { u, _ = Context.auth.findUser(user, pass) return u } return webUser{} } a.lock.Lock() defer a.lock.Unlock() s, ok := a.sessions[cookie.Value] if !ok { return webUser{} } for _, u = range a.users { if u.Name == s.userName { return u } } return webUser{} } // GetUsers - get users func (a *Auth) GetUsers() []webUser { a.lock.Lock() users := a.users a.lock.Unlock() return users } // AuthRequired - if authentication is required func (a *Auth) AuthRequired() bool { if GLMode { return true } a.lock.Lock() r := (len(a.users) != 0) a.lock.Unlock() return r }