headscale/protocol_common.go

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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
}
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// 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, 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, 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 = &registerRequest.Expiry
}
h.registrationCache.Set(
newMachine.NodeKey,
newMachine,
registerCacheExpiration,
)
h.handleNewMachineCommon(writer, 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, *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, *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,
registerRequest,
*machine,
machineKey,
)
return
}
// The machine has expired
h.handleMachineExpiredCommon(writer, 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,
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
}
aclTags := pak.toProto().AclTags
if len(aclTags) > 0 {
// This conditional preserves the existing behaviour, although SaaS would reset the tags on auth-key login
err = h.SetTags(machine, aclTags)
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if err != nil {
log.Error().
Caller().
Bool("noise", machineKey.IsZero()).
Str("machine", machine.Hostname).
Strs("aclTags", aclTags).
Err(err).
Msg("Failed to set tags after refreshing machine")
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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: &registerRequest.Expiry,
NodeKey: nodeKey,
LastSeen: &now,
AuthKeyID: uint(pak.ID),
ForcedTags: pak.toProto().AclTags,
}
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,
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.oauth2Config != nil {
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,
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,
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,
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,
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, registerRequest, machineKey)
return
}
if h.oauth2Config != nil {
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")
}