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Move common parts of the protocol to dedicated file

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This commit is contained in:
Juan Font Alonso 2022-08-14 21:15:58 +02:00
parent e640c6df05
commit d0898ecabc
3 changed files with 113 additions and 281 deletions
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281
api.go
View file

@ -4,19 +4,15 @@ import (
"bytes"
"encoding/binary"
"encoding/json"
"errors"
"fmt"
"html/template"
"io"
"net/http"
"strconv"
"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"
)
@ -77,62 +73,6 @@ func (h *Headscale) HealthHandler(
respond(nil)
}
// 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 != "" {
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
}
if clientCapabilityVersion >= NoiseCapabilityVersion {
// Tailscale has a different key for the TS2021 protocol
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
}
}
// 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")
}
}
type registerWebAPITemplateConfig struct {
Key string
}
@ -211,191 +151,6 @@ func (h *Headscale) RegisterWebAPI(
}
}
// RegistrationHandler handles the actual registration process of a machine
// Endpoint /machine/:mkey.
func (h *Headscale) RegistrationHandler(
writer http.ResponseWriter,
req *http.Request,
) {
vars := mux.Vars(req)
machineKeyStr, ok := vars["mkey"]
if !ok || machineKeyStr == "" {
log.Error().
Str("handler", "RegistrationHandler").
Msg("No machine ID in request")
http.Error(writer, "No machine ID in request", http.StatusBadRequest)
return
}
body, _ := io.ReadAll(req.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(writer, "Cannot parse machine key", http.StatusBadRequest)
return
}
registerRequest := tailcfg.RegisterRequest{}
err = decode(body, &registerRequest, &machineKey, h.privateKey)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Cannot decode message")
machineRegistrations.WithLabelValues("unknown", "web", "error", "unknown").Inc()
http.Error(writer, "Cannot decode message", http.StatusBadRequest)
return
}
now := time.Now().UTC()
machine, err := h.GetMachineByMachineKey(machineKey)
if errors.Is(err, gorm.ErrRecordNotFound) {
machineKeyStr := MachinePublicKeyStripPrefix(machineKey)
// If the machine has AuthKey set, handle registration via PreAuthKeys
if registerRequest.Auth.AuthKey != "" {
h.handleAuthKey(writer, req, machineKey, registerRequest)
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).
Msg("Machine is waiting for interactive login")
ticker := time.NewTicker(registrationHoldoff)
select {
case <-req.Context().Done():
return
case <-ticker.C:
h.handleMachineRegistrationNew(writer, req, machineKey, registerRequest)
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).
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: machineKeyStr,
Hostname: registerRequest.Hostinfo.Hostname,
GivenName: givenName,
NodeKey: NodePublicKeyStripPrefix(registerRequest.NodeKey),
LastSeen: &now,
Expiry: &time.Time{},
}
if !registerRequest.Expiry.IsZero() {
log.Trace().
Caller().
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.handleMachineRegistrationNew(writer, req, machineKey, registerRequest)
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.handleMachineLogOut(writer, req, 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(writer, req, machineKey, *machine)
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.handleMachineRefreshKey(
writer,
req,
machineKey,
registerRequest,
*machine,
)
return
}
// The machine has expired
h.handleMachineExpired(writer, req, machineKey, registerRequest, *machine)
return
}
}
func (h *Headscale) getLegacyMapResponseData(
machineKey key.MachinePublic,
mapRequest tailcfg.MapRequest,
@ -436,42 +191,6 @@ func (h *Headscale) getLegacyMapResponseData(
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 == ZstdCompression {
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(
writer http.ResponseWriter,
req *http.Request,

66
protocol_common.go Normal file
View file

@ -0,0 +1,66 @@
package headscale
import (
"encoding/json"
"net/http"
"strconv"
"github.com/rs/zerolog/log"
"tailscale.com/tailcfg"
)
// 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 != "" {
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
}
if clientCapabilityVersion >= NoiseCapabilityVersion {
// Tailscale has a different key for the TS2021 protocol
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
}
}
// 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")
}
}

47
protocol_common_utils.go Normal file
View file

@ -0,0 +1,47 @@
package headscale
import (
"encoding/binary"
"encoding/json"
"github.com/klauspost/compress/zstd"
"github.com/rs/zerolog/log"
"tailscale.com/tailcfg"
"tailscale.com/types/key"
)
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 == ZstdCompression {
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
}