headscale/api.go

729 lines
19 KiB
Go

package headscale
import (
"bytes"
"encoding/binary"
"encoding/json"
"errors"
"fmt"
"html/template"
"io"
"net/http"
"strings"
"time"
"github.com/gorilla/mux"
"github.com/klauspost/compress/zstd"
"github.com/rs/zerolog/log"
"gorm.io/gorm"
"tailscale.com/tailcfg"
"tailscale.com/types/key"
)
const (
reservedResponseHeaderSize = 4
RegisterMethodAuthKey = "authkey"
RegisterMethodOIDC = "oidc"
RegisterMethodCLI = "cli"
ErrRegisterMethodCLIDoesNotSupportExpire = Error(
"machines registered with CLI does not support expire",
)
)
// KeyHandler provides the Headscale pub key
// Listens in /key.
func (h *Headscale) KeyHandler(
w http.ResponseWriter,
r *http.Request,
) {
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write([]byte(MachinePublicKeyStripPrefix(h.privateKey.Public())))
}
type registerWebAPITemplateConfig struct {
Key string
}
var registerWebAPITemplate = template.Must(
template.New("registerweb").Parse(`
<html>
<head>
<title>Registration - Headscale</title>
</head>
<body>
<h1>headscale</h1>
<h2>Machine registration</h2>
<p>
Run the command below in the headscale server to add this machine to your network:
</p>
<pre><code>headscale -n NAMESPACE nodes register --key {{.Key}}</code></pre>
</body>
</html>
`))
// RegisterWebAPI shows a simple message in the browser to point to the CLI
// Listens in /register.
func (h *Headscale) RegisterWebAPI(
w http.ResponseWriter,
r *http.Request,
) {
machineKeyStr := r.URL.Query().Get("key")
if machineKeyStr == "" {
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.WriteHeader(http.StatusBadRequest)
w.Write([]byte("Wrong params"))
return
}
var content bytes.Buffer
if err := registerWebAPITemplate.Execute(&content, registerWebAPITemplateConfig{
Key: machineKeyStr,
}); err != nil {
log.Error().
Str("func", "RegisterWebAPI").
Err(err).
Msg("Could not render register web API template")
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte("Could not render register web API template"))
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write(content.Bytes())
}
// RegistrationHandler handles the actual registration process of a machine
// Endpoint /machine/:mkey.
func (h *Headscale) RegistrationHandler(
w http.ResponseWriter,
r *http.Request,
) {
vars := mux.Vars(r)
machineKeyStr, ok := vars["mkey"]
if !ok || machineKeyStr == "" {
log.Error().
Str("handler", "RegistrationHandler").
Msg("No machine ID in request")
http.Error(w, "No machine ID in request", http.StatusBadRequest)
return
}
body, _ := io.ReadAll(r.Body)
var machineKey key.MachinePublic
err := machineKey.UnmarshalText([]byte(MachinePublicKeyEnsurePrefix(machineKeyStr)))
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot parse machine key")
machineRegistrations.WithLabelValues("unknown", "web", "error", "unknown").Inc()
http.Error(w, "Cannot parse machine key", http.StatusBadRequest)
return
}
req := tailcfg.RegisterRequest{}
err = decode(body, &req, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot decode message")
machineRegistrations.WithLabelValues("unknown", "web", "error", "unknown").Inc()
http.Error(w, "Cannot decode message", http.StatusBadRequest)
return
}
now := time.Now().UTC()
machine, err := h.GetMachineByMachineKey(machineKey)
if errors.Is(err, gorm.ErrRecordNotFound) {
log.Info().Str("machine", req.Hostinfo.Hostname).Msg("New machine")
machineKeyStr := MachinePublicKeyStripPrefix(machineKey)
// If the machine has AuthKey set, handle registration via PreAuthKeys
if req.Auth.AuthKey != "" {
h.handleAuthKey(w, r, machineKey, req)
return
}
givenName, err := h.GenerateGivenName(req.Hostinfo.Hostname)
if err != nil {
log.Error().
Caller().
Str("func", "RegistrationHandler").
Str("hostinfo.name", req.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: machineKeyStr,
Hostname: req.Hostinfo.Hostname,
GivenName: givenName,
NodeKey: NodePublicKeyStripPrefix(req.NodeKey),
LastSeen: &now,
Expiry: &time.Time{},
}
if !req.Expiry.IsZero() {
log.Trace().
Caller().
Str("machine", req.Hostinfo.Hostname).
Time("expiry", req.Expiry).
Msg("Non-zero expiry time requested")
newMachine.Expiry = &req.Expiry
}
h.registrationCache.Set(
machineKeyStr,
newMachine,
registerCacheExpiration,
)
h.handleMachineRegistrationNew(w, r, machineKey, req)
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(req.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 !req.Expiry.IsZero() && req.Expiry.UTC().Before(now) {
h.handleMachineLogOut(w, r, machineKey, *machine)
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.handleMachineValidRegistration(w, r, machineKey, *machine)
return
}
}
// The NodeKey we have matches OldNodeKey, which means this is a refresh after a key expiration
if machine.NodeKey == NodePublicKeyStripPrefix(req.OldNodeKey) &&
!machine.isExpired() {
h.handleMachineRefreshKey(w, r, machineKey, req, *machine)
return
}
// The machine has expired
h.handleMachineExpired(w, r, machineKey, req, *machine)
return
}
}
func (h *Headscale) getMapResponse(
machineKey key.MachinePublic,
req tailcfg.MapRequest,
machine *Machine,
) ([]byte, error) {
log.Trace().
Str("func", "getMapResponse").
Str("machine", req.Hostinfo.Hostname).
Msg("Creating Map response")
node, err := machine.toNode(h.cfg.BaseDomain, h.cfg.DNSConfig, true)
if err != nil {
log.Error().
Caller().
Str("func", "getMapResponse").
Err(err).
Msg("Cannot convert to node")
return nil, err
}
peers, err := h.getValidPeers(machine)
if err != nil {
log.Error().
Caller().
Str("func", "getMapResponse").
Err(err).
Msg("Cannot fetch peers")
return nil, err
}
profiles := getMapResponseUserProfiles(*machine, peers)
nodePeers, err := peers.toNodes(h.cfg.BaseDomain, h.cfg.DNSConfig, true)
if err != nil {
log.Error().
Caller().
Str("func", "getMapResponse").
Err(err).
Msg("Failed to convert peers to Tailscale nodes")
return nil, err
}
dnsConfig := getMapResponseDNSConfig(
h.cfg.DNSConfig,
h.cfg.BaseDomain,
*machine,
peers,
)
resp := tailcfg.MapResponse{
KeepAlive: false,
Node: node,
Peers: nodePeers,
DNSConfig: dnsConfig,
Domain: h.cfg.BaseDomain,
PacketFilter: h.aclRules,
DERPMap: h.DERPMap,
UserProfiles: profiles,
Debug: &tailcfg.Debug{
DisableLogTail: !h.cfg.LogTail.Enabled,
RandomizeClientPort: h.cfg.RandomizeClientPort,
},
}
log.Trace().
Str("func", "getMapResponse").
Str("machine", req.Hostinfo.Hostname).
// Interface("payload", resp).
Msgf("Generated map response: %s", tailMapResponseToString(resp))
var respBody []byte
if req.Compress == "zstd" {
src, err := json.Marshal(resp)
if err != nil {
log.Error().
Caller().
Str("func", "getMapResponse").
Err(err).
Msg("Failed to marshal response for the client")
return nil, err
}
encoder, _ := zstd.NewWriter(nil)
srcCompressed := encoder.EncodeAll(src, nil)
respBody = h.privateKey.SealTo(machineKey, srcCompressed)
} else {
respBody, err = encode(resp, &machineKey, h.privateKey)
if err != nil {
return nil, err
}
}
// declare the incoming size on the first 4 bytes
data := make([]byte, reservedResponseHeaderSize)
binary.LittleEndian.PutUint32(data, uint32(len(respBody)))
data = append(data, respBody...)
return data, nil
}
func (h *Headscale) getMapKeepAliveResponse(
machineKey key.MachinePublic,
mapRequest tailcfg.MapRequest,
) ([]byte, error) {
mapResponse := tailcfg.MapResponse{
KeepAlive: true,
}
var respBody []byte
var err error
if mapRequest.Compress == "zstd" {
src, err := json.Marshal(mapResponse)
if err != nil {
log.Error().
Caller().
Str("func", "getMapKeepAliveResponse").
Err(err).
Msg("Failed to marshal keepalive response for the client")
return nil, err
}
encoder, _ := zstd.NewWriter(nil)
srcCompressed := encoder.EncodeAll(src, nil)
respBody = h.privateKey.SealTo(machineKey, srcCompressed)
} else {
respBody, err = encode(mapResponse, &machineKey, h.privateKey)
if err != nil {
return nil, err
}
}
data := make([]byte, reservedResponseHeaderSize)
binary.LittleEndian.PutUint32(data, uint32(len(respBody)))
data = append(data, respBody...)
return data, nil
}
func (h *Headscale) handleMachineLogOut(
w http.ResponseWriter,
r *http.Request,
machineKey key.MachinePublic,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
log.Info().
Str("machine", machine.Hostname).
Msg("Client requested logout")
h.ExpireMachine(&machine)
resp.AuthURL = ""
resp.MachineAuthorized = false
resp.User = *machine.Namespace.toUser()
respBody, err := encode(resp, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot encode message")
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write(respBody)
}
func (h *Headscale) handleMachineValidRegistration(
w http.ResponseWriter,
r *http.Request,
machineKey key.MachinePublic,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
// The machine registration is valid, respond with redirect to /map
log.Debug().
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 := encode(resp, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot encode message")
machineRegistrations.WithLabelValues("update", "web", "error", machine.Namespace.Name).
Inc()
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
machineRegistrations.WithLabelValues("update", "web", "success", machine.Namespace.Name).
Inc()
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write(respBody)
}
func (h *Headscale) handleMachineExpired(
w http.ResponseWriter,
r *http.Request,
machineKey key.MachinePublic,
registerRequest tailcfg.RegisterRequest,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
// The client has registered before, but has expired
log.Debug().
Str("machine", machine.Hostname).
Msg("Machine registration has expired. Sending a authurl to register")
if registerRequest.Auth.AuthKey != "" {
h.handleAuthKey(w, r, machineKey, registerRequest)
return
}
if h.cfg.OIDC.Issuer != "" {
resp.AuthURL = fmt.Sprintf("%s/oidc/register/%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"), machineKey.String())
} else {
resp.AuthURL = fmt.Sprintf("%s/register?key=%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"), machineKey.String())
}
respBody, err := encode(resp, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot encode message")
machineRegistrations.WithLabelValues("reauth", "web", "error", machine.Namespace.Name).
Inc()
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
machineRegistrations.WithLabelValues("reauth", "web", "success", machine.Namespace.Name).
Inc()
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write(respBody)
}
func (h *Headscale) handleMachineRefreshKey(
w http.ResponseWriter,
r *http.Request,
machineKey key.MachinePublic,
registerRequest tailcfg.RegisterRequest,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
log.Debug().
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(w, "Internal server error", http.StatusInternalServerError)
return
}
resp.AuthURL = ""
resp.User = *machine.Namespace.toUser()
respBody, err := encode(resp, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot encode message")
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write(respBody)
}
func (h *Headscale) handleMachineRegistrationNew(
w http.ResponseWriter,
r *http.Request,
machineKey key.MachinePublic,
registerRequest tailcfg.RegisterRequest,
) {
resp := tailcfg.RegisterResponse{}
// The machine registration is new, redirect the client to the registration URL
log.Debug().
Str("machine", registerRequest.Hostinfo.Hostname).
Msg("The node is sending us a new NodeKey, sending auth url")
if h.cfg.OIDC.Issuer != "" {
resp.AuthURL = fmt.Sprintf(
"%s/oidc/register/%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"),
machineKey.String(),
)
} else {
resp.AuthURL = fmt.Sprintf("%s/register?key=%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"), MachinePublicKeyStripPrefix(machineKey))
}
respBody, err := encode(resp, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot encode message")
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write(respBody)
}
// TODO: check if any locks are needed around IP allocation.
func (h *Headscale) handleAuthKey(
w http.ResponseWriter,
r *http.Request,
machineKey key.MachinePublic,
registerRequest tailcfg.RegisterRequest,
) {
machineKeyStr := MachinePublicKeyStripPrefix(machineKey)
log.Debug().
Str("func", "handleAuthKey").
Str("machine", registerRequest.Hostinfo.Hostname).
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", "handleAuthKey").
Str("machine", registerRequest.Hostinfo.Hostname).
Err(err).
Msg("Failed authentication via AuthKey")
resp.MachineAuthorized = false
respBody, err := encode(resp, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Str("func", "handleAuthKey").
Str("machine", registerRequest.Hostinfo.Hostname).
Err(err).
Msg("Cannot encode message")
http.Error(w, "Internal server error", http.StatusInternalServerError)
machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name).
Inc()
return
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusUnauthorized)
w.Write(respBody)
log.Error().
Caller().
Str("func", "handleAuthKey").
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", "handleAuthKey").
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.GetMachineByMachineKey(machineKey)
if machine != nil {
log.Trace().
Caller().
Str("machine", machine.Hostname).
Msg("machine already registered, refreshing with new auth key")
machine.NodeKey = nodeKey
machine.AuthKeyID = uint(pak.ID)
h.RefreshMachine(machine, registerRequest.Expiry)
} else {
now := time.Now().UTC()
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
}
machineToRegister := Machine{
Hostname: registerRequest.Hostinfo.Hostname,
GivenName: givenName,
NamespaceID: pak.Namespace.ID,
MachineKey: machineKeyStr,
RegisterMethod: RegisterMethodAuthKey,
Expiry: &registerRequest.Expiry,
NodeKey: nodeKey,
LastSeen: &now,
AuthKeyID: uint(pak.ID),
}
machine, err = h.RegisterMachine(
machineToRegister,
)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("could not register machine")
machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name).
Inc()
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
}
h.UsePreAuthKey(pak)
resp.MachineAuthorized = true
resp.User = *pak.Namespace.toUser()
respBody, err := encode(resp, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Str("func", "handleAuthKey").
Str("machine", registerRequest.Hostinfo.Hostname).
Err(err).
Msg("Cannot encode message")
machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "error", pak.Namespace.Name).
Inc()
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
machineRegistrations.WithLabelValues("new", RegisterMethodAuthKey, "success", pak.Namespace.Name).
Inc()
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusOK)
w.Write(respBody)
log.Info().
Str("func", "handleAuthKey").
Str("machine", registerRequest.Hostinfo.Hostname).
Str("ips", strings.Join(machine.IPAddresses.ToStringSlice(), ", ")).
Msg("Successfully authenticated via AuthKey")
}