package headscale import ( "encoding/json" "errors" "fmt" "net/http" "strconv" "strings" "time" "github.com/rs/zerolog/log" "gorm.io/gorm" "tailscale.com/tailcfg" "tailscale.com/types/key" ) const ( // The CapabilityVersion is used by Tailscale clients to indicate // their codebase version. Tailscale clients can communicate over TS2021 // from CapabilityVersion 28, but we only have good support for it // since https://github.com/tailscale/tailscale/pull/4323 (Noise in any HTTPS port). // // Related to this change, there is https://github.com/tailscale/tailscale/pull/5379, // where CapabilityVersion 39 is introduced to indicate #4323 was merged. // // See also https://github.com/tailscale/tailscale/blob/main/tailcfg/tailcfg.go NoiseCapabilityVersion = 39 ) // KeyHandler provides the Headscale pub key // Listens in /key. func (h *Headscale) KeyHandler( writer http.ResponseWriter, req *http.Request, ) { // New Tailscale clients send a 'v' parameter to indicate the CurrentCapabilityVersion clientCapabilityStr := req.URL.Query().Get("v") if clientCapabilityStr != "" { log.Debug(). Str("handler", "/key"). Str("v", clientCapabilityStr). Msg("New noise client") clientCapabilityVersion, err := strconv.Atoi(clientCapabilityStr) if err != nil { writer.Header().Set("Content-Type", "text/plain; charset=utf-8") writer.WriteHeader(http.StatusBadRequest) _, err := writer.Write([]byte("Wrong params")) if err != nil { log.Error(). Caller(). Err(err). Msg("Failed to write response") } return } // TS2021 (Tailscale v2 protocol) requires to have a different key if clientCapabilityVersion >= NoiseCapabilityVersion { resp := tailcfg.OverTLSPublicKeyResponse{ LegacyPublicKey: h.privateKey.Public(), PublicKey: h.noisePrivateKey.Public(), } writer.Header().Set("Content-Type", "application/json") writer.WriteHeader(http.StatusOK) err = json.NewEncoder(writer).Encode(resp) if err != nil { log.Error(). Caller(). Err(err). Msg("Failed to write response") } return } } log.Debug(). Str("handler", "/key"). Msg("New legacy client") // Old clients don't send a 'v' parameter, so we send the legacy public key writer.Header().Set("Content-Type", "text/plain; charset=utf-8") writer.WriteHeader(http.StatusOK) _, err := writer.Write([]byte(MachinePublicKeyStripPrefix(h.privateKey.Public()))) if err != nil { log.Error(). Caller(). Err(err). Msg("Failed to write response") } } // handleRegisterCommon is the common logic for registering a client in the legacy and Noise protocols // // When using Noise, the machineKey is Zero. func (h *Headscale) handleRegisterCommon( writer http.ResponseWriter, req *http.Request, registerRequest tailcfg.RegisterRequest, machineKey key.MachinePublic, ) { now := time.Now().UTC() machine, err := h.GetMachineByAnyNodeKey(registerRequest.NodeKey, registerRequest.OldNodeKey) if errors.Is(err, gorm.ErrRecordNotFound) { // If the machine has AuthKey set, handle registration via PreAuthKeys if registerRequest.Auth.AuthKey != "" { h.handleAuthKeyCommon(writer, req, registerRequest, machineKey) return } // Check if the node is waiting for interactive login. // // TODO(juan): We could use this field to improve our protocol implementation, // and hold the request until the client closes it, or the interactive // login is completed (i.e., the user registers the machine). // This is not implemented yet, as it is no strictly required. The only side-effect // is that the client will hammer headscale with requests until it gets a // successful RegisterResponse. if registerRequest.Followup != "" { if _, ok := h.registrationCache.Get(NodePublicKeyStripPrefix(registerRequest.NodeKey)); ok { log.Debug(). Caller(). Str("machine", registerRequest.Hostinfo.Hostname). Str("node_key", registerRequest.NodeKey.ShortString()). Str("node_key_old", registerRequest.OldNodeKey.ShortString()). Str("follow_up", registerRequest.Followup). Bool("noise", machineKey.IsZero()). Msg("Machine is waiting for interactive login") ticker := time.NewTicker(registrationHoldoff) select { case <-req.Context().Done(): return case <-ticker.C: h.handleNewMachineCommon(writer, req, registerRequest, machineKey) return } } } log.Info(). Caller(). Str("machine", registerRequest.Hostinfo.Hostname). Str("node_key", registerRequest.NodeKey.ShortString()). Str("node_key_old", registerRequest.OldNodeKey.ShortString()). Str("follow_up", registerRequest.Followup). Bool("noise", machineKey.IsZero()). Msg("New machine not yet in the database") givenName, err := h.GenerateGivenName(registerRequest.Hostinfo.Hostname) if err != nil { log.Error(). Caller(). Str("func", "RegistrationHandler"). Str("hostinfo.name", registerRequest.Hostinfo.Hostname). Err(err) return } // The machine did not have a key to authenticate, which means // that we rely on a method that calls back some how (OpenID or CLI) // We create the machine and then keep it around until a callback // happens newMachine := Machine{ MachineKey: MachinePublicKeyStripPrefix(machineKey), Hostname: registerRequest.Hostinfo.Hostname, GivenName: givenName, NodeKey: NodePublicKeyStripPrefix(registerRequest.NodeKey), LastSeen: &now, Expiry: &time.Time{}, } if !registerRequest.Expiry.IsZero() { log.Trace(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Time("expiry", registerRequest.Expiry). Msg("Non-zero expiry time requested") newMachine.Expiry = ®isterRequest.Expiry } h.registrationCache.Set( newMachine.NodeKey, newMachine, registerCacheExpiration, ) h.handleNewMachineCommon(writer, req, registerRequest, machineKey) return } // The machine is already registered, so we need to pass through reauth or key update. if machine != nil { // If the NodeKey stored in headscale is the same as the key presented in a registration // request, then we have a node that is either: // - Trying to log out (sending a expiry in the past) // - A valid, registered machine, looking for the node map // - Expired machine wanting to reauthenticate if machine.NodeKey == NodePublicKeyStripPrefix(registerRequest.NodeKey) { // The client sends an Expiry in the past if the client is requesting to expire the key (aka logout) // https://github.com/tailscale/tailscale/blob/main/tailcfg/tailcfg.go#L648 if !registerRequest.Expiry.IsZero() && registerRequest.Expiry.UTC().Before(now) { h.handleMachineLogOutCommon(writer, req, *machine, machineKey) return } // If machine is not expired, and is register, we have a already accepted this machine, // let it proceed with a valid registration if !machine.isExpired() { h.handleMachineValidRegistrationCommon(writer, req, *machine, machineKey) return } } // The NodeKey we have matches OldNodeKey, which means this is a refresh after a key expiration if machine.NodeKey == NodePublicKeyStripPrefix(registerRequest.OldNodeKey) && !machine.isExpired() { h.handleMachineRefreshKeyCommon( writer, req, registerRequest, *machine, machineKey, ) return } // The machine has expired h.handleMachineExpiredCommon(writer, req, registerRequest, *machine, machineKey) machine.Expiry = &time.Time{} h.registrationCache.Set( NodePublicKeyStripPrefix(registerRequest.NodeKey), *machine, registerCacheExpiration, ) return } } // handleAuthKeyCommon contains the logic to manage auth key client registration // It is used both by the legacy and the new Noise protocol. // When using Noise, the machineKey is Zero. // // TODO: check if any locks are needed around IP allocation. func (h *Headscale) handleAuthKeyCommon( writer http.ResponseWriter, req *http.Request, registerRequest tailcfg.RegisterRequest, machineKey key.MachinePublic, ) { log.Debug(). Str("func", "handleAuthKeyCommon"). Str("machine", registerRequest.Hostinfo.Hostname). Bool("noise", machineKey.IsZero()). Msgf("Processing auth key for %s", registerRequest.Hostinfo.Hostname) resp := tailcfg.RegisterResponse{} pak, err := h.checkKeyValidity(registerRequest.Auth.AuthKey) if err != nil { log.Error(). Caller(). Str("func", "handleAuthKeyCommon"). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Err(err). Msg("Failed authentication via AuthKey") resp.MachineAuthorized = false respBody, err := h.marshalResponse(resp, machineKey) if err != nil { log.Error(). Caller(). Str("func", "handleAuthKeyCommon"). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Err(err). Msg("Cannot encode message") http.Error(writer, "Internal server error", http.StatusInternalServerError) machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name). Inc() return } writer.Header().Set("Content-Type", "application/json; charset=utf-8") writer.WriteHeader(http.StatusUnauthorized) _, err = writer.Write(respBody) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Failed to write response") } log.Error(). Caller(). Str("func", "handleAuthKeyCommon"). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Msg("Failed authentication via AuthKey") if pak != nil { machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name). Inc() } else { machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", "unknown").Inc() } return } log.Debug(). Str("func", "handleAuthKeyCommon"). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Msg("Authentication key was valid, proceeding to acquire IP addresses") nodeKey := NodePublicKeyStripPrefix(registerRequest.NodeKey) // retrieve machine information if it exist // The error is not important, because if it does not // exist, then this is a new machine and we will move // on to registration. machine, _ := h.GetMachineByAnyNodeKey(registerRequest.NodeKey, registerRequest.OldNodeKey) if machine != nil { log.Trace(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("machine was already registered before, refreshing with new auth key") machine.NodeKey = nodeKey machine.AuthKeyID = uint(pak.ID) err := h.RefreshMachine(machine, registerRequest.Expiry) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Err(err). Msg("Failed to refresh machine") return } } else { now := time.Now().UTC() givenName, err := h.GenerateGivenName(registerRequest.Hostinfo.Hostname) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Str("func", "RegistrationHandler"). Str("hostinfo.name", registerRequest.Hostinfo.Hostname). Err(err) return } machineToRegister := Machine{ Hostname: registerRequest.Hostinfo.Hostname, GivenName: givenName, NamespaceID: pak.Namespace.ID, MachineKey: MachinePublicKeyStripPrefix(machineKey), RegisterMethod: RegisterMethodAuthKey, Expiry: ®isterRequest.Expiry, NodeKey: nodeKey, LastSeen: &now, AuthKeyID: uint(pak.ID), } machine, err = h.RegisterMachine( machineToRegister, ) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("could not register machine") machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name). Inc() http.Error(writer, "Internal server error", http.StatusInternalServerError) return } } err = h.UsePreAuthKey(pak) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Failed to use pre-auth key") machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name). Inc() http.Error(writer, "Internal server error", http.StatusInternalServerError) return } resp.MachineAuthorized = true resp.User = *pak.Namespace.toUser() respBody, err := h.marshalResponse(resp, machineKey) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Str("func", "handleAuthKeyCommon"). Str("machine", registerRequest.Hostinfo.Hostname). Err(err). Msg("Cannot encode message") machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name). Inc() http.Error(writer, "Internal server error", http.StatusInternalServerError) return } machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "success", pak.Namespace.Name). Inc() writer.Header().Set("Content-Type", "application/json; charset=utf-8") writer.WriteHeader(http.StatusOK) _, err = writer.Write(respBody) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Failed to write response") } log.Info(). Str("func", "handleAuthKeyCommon"). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Str("ips", strings.Join(machine.IPAddresses.ToStringSlice(), ", ")). Msg("Successfully authenticated via AuthKey") } // handleNewMachineCommon exposes for both legacy and Noise the functionality to get a URL // for authorizing the machine. This url is then showed to the user by the local Tailscale client. func (h *Headscale) handleNewMachineCommon( writer http.ResponseWriter, req *http.Request, registerRequest tailcfg.RegisterRequest, machineKey key.MachinePublic, ) { resp := tailcfg.RegisterResponse{} // The machine registration is new, redirect the client to the registration URL log.Debug(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Msg("The node seems to be new, sending auth url") if h.cfg.OIDC.Issuer != "" { resp.AuthURL = fmt.Sprintf( "%s/oidc/register/%s", strings.TrimSuffix(h.cfg.ServerURL, "/"), NodePublicKeyStripPrefix(registerRequest.NodeKey), ) } else { resp.AuthURL = fmt.Sprintf("%s/register/%s", strings.TrimSuffix(h.cfg.ServerURL, "/"), NodePublicKeyStripPrefix(registerRequest.NodeKey)) } respBody, err := h.marshalResponse(resp, machineKey) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Cannot encode message") http.Error(writer, "Internal server error", http.StatusInternalServerError) return } writer.Header().Set("Content-Type", "application/json; charset=utf-8") writer.WriteHeader(http.StatusOK) _, err = writer.Write(respBody) if err != nil { log.Error(). Bool("noise", machineKey.IsZero()). Caller(). Err(err). Msg("Failed to write response") } log.Info(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", registerRequest.Hostinfo.Hostname). Msg("Successfully sent auth url") } func (h *Headscale) handleMachineLogOutCommon( writer http.ResponseWriter, req *http.Request, machine Machine, machineKey key.MachinePublic, ) { resp := tailcfg.RegisterResponse{} log.Info(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("Client requested logout") err := h.ExpireMachine(&machine) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Str("func", "handleMachineLogOutCommon"). Err(err). Msg("Failed to expire machine") http.Error(writer, "Internal server error", http.StatusInternalServerError) return } resp.AuthURL = "" resp.MachineAuthorized = false resp.User = *machine.Namespace.toUser() respBody, err := h.marshalResponse(resp, machineKey) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Cannot encode message") http.Error(writer, "Internal server error", http.StatusInternalServerError) return } writer.Header().Set("Content-Type", "application/json; charset=utf-8") writer.WriteHeader(http.StatusOK) _, err = writer.Write(respBody) if err != nil { log.Error(). Bool("noise", machineKey.IsZero()). Caller(). Err(err). Msg("Failed to write response") } log.Info(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("Successfully logged out") } func (h *Headscale) handleMachineValidRegistrationCommon( writer http.ResponseWriter, req *http.Request, machine Machine, machineKey key.MachinePublic, ) { resp := tailcfg.RegisterResponse{} // The machine registration is valid, respond with redirect to /map log.Debug(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("Client is registered and we have the current NodeKey. All clear to /map") resp.AuthURL = "" resp.MachineAuthorized = true resp.User = *machine.Namespace.toUser() resp.Login = *machine.Namespace.toLogin() respBody, err := h.marshalResponse(resp, machineKey) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Cannot encode message") machineRegistrations.WithLabelValues("update", "web", "error", machine.Namespace.Name). Inc() http.Error(writer, "Internal server error", http.StatusInternalServerError) return } machineRegistrations.WithLabelValues("update", "web", "success", machine.Namespace.Name). Inc() writer.Header().Set("Content-Type", "application/json; charset=utf-8") writer.WriteHeader(http.StatusOK) _, err = writer.Write(respBody) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Failed to write response") } log.Info(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("Machine successfully authorized") } func (h *Headscale) handleMachineRefreshKeyCommon( writer http.ResponseWriter, req *http.Request, registerRequest tailcfg.RegisterRequest, machine Machine, machineKey key.MachinePublic, ) { resp := tailcfg.RegisterResponse{} log.Debug(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("We have the OldNodeKey in the database. This is a key refresh") machine.NodeKey = NodePublicKeyStripPrefix(registerRequest.NodeKey) if err := h.db.Save(&machine).Error; err != nil { log.Error(). Caller(). Err(err). Msg("Failed to update machine key in the database") http.Error(writer, "Internal server error", http.StatusInternalServerError) return } resp.AuthURL = "" resp.User = *machine.Namespace.toUser() respBody, err := h.marshalResponse(resp, machineKey) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Cannot encode message") http.Error(writer, "Internal server error", http.StatusInternalServerError) return } writer.Header().Set("Content-Type", "application/json; charset=utf-8") writer.WriteHeader(http.StatusOK) _, err = writer.Write(respBody) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Failed to write response") } log.Info(). Caller(). Bool("noise", machineKey.IsZero()). Str("node_key", registerRequest.NodeKey.ShortString()). Str("old_node_key", registerRequest.OldNodeKey.ShortString()). Str("machine", machine.Hostname). Msg("Machine successfully refreshed") } func (h *Headscale) handleMachineExpiredCommon( writer http.ResponseWriter, req *http.Request, registerRequest tailcfg.RegisterRequest, machine Machine, machineKey key.MachinePublic, ) { resp := tailcfg.RegisterResponse{} // The client has registered before, but has expired log.Debug(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("Machine registration has expired. Sending a authurl to register") if registerRequest.Auth.AuthKey != "" { h.handleAuthKeyCommon(writer, req, registerRequest, machineKey) return } if h.cfg.OIDC.Issuer != "" { resp.AuthURL = fmt.Sprintf("%s/oidc/register/%s", strings.TrimSuffix(h.cfg.ServerURL, "/"), NodePublicKeyStripPrefix(registerRequest.NodeKey)) } else { resp.AuthURL = fmt.Sprintf("%s/register/%s", strings.TrimSuffix(h.cfg.ServerURL, "/"), NodePublicKeyStripPrefix(registerRequest.NodeKey)) } respBody, err := h.marshalResponse(resp, machineKey) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Cannot encode message") machineRegistrations.WithLabelValues("reauth", "web", "error", machine.Namespace.Name). Inc() http.Error(writer, "Internal server error", http.StatusInternalServerError) return } machineRegistrations.WithLabelValues("reauth", "web", "success", machine.Namespace.Name). Inc() writer.Header().Set("Content-Type", "application/json; charset=utf-8") writer.WriteHeader(http.StatusOK) _, err = writer.Write(respBody) if err != nil { log.Error(). Caller(). Bool("noise", machineKey.IsZero()). Err(err). Msg("Failed to write response") } log.Info(). Caller(). Bool("noise", machineKey.IsZero()). Str("machine", machine.Hostname). Msg("Auth URL for reauthenticate successfully sent") }