mirror of
https://github.com/juanfont/headscale.git
synced 2024-12-20 19:09:07 +01:00
658 lines
17 KiB
Go
658 lines
17 KiB
Go
package headscale
|
|
|
|
import (
|
|
"bytes"
|
|
"context"
|
|
"crypto/rand"
|
|
"encoding/hex"
|
|
"errors"
|
|
"fmt"
|
|
"html/template"
|
|
"net/http"
|
|
"strings"
|
|
"time"
|
|
|
|
"github.com/coreos/go-oidc/v3/oidc"
|
|
"github.com/gorilla/mux"
|
|
"github.com/rs/zerolog/log"
|
|
"golang.org/x/oauth2"
|
|
"tailscale.com/types/key"
|
|
)
|
|
|
|
const (
|
|
randomByteSize = 16
|
|
|
|
errEmptyOIDCCallbackParams = Error("empty OIDC callback params")
|
|
errNoOIDCIDToken = Error("could not extract ID Token for OIDC callback")
|
|
errOIDCAllowedDomains = Error("authenticated principal does not match any allowed domain")
|
|
errOIDCAllowedUsers = Error("authenticated principal does not match any allowed user")
|
|
errOIDCInvalidMachineState = Error("requested machine state key expired before authorisation completed")
|
|
errOIDCMachineKeyMissing = Error("could not get machine key from cache")
|
|
)
|
|
|
|
type IDTokenClaims struct {
|
|
Name string `json:"name,omitempty"`
|
|
Groups []string `json:"groups,omitempty"`
|
|
Email string `json:"email"`
|
|
Username string `json:"preferred_username,omitempty"`
|
|
}
|
|
|
|
func (h *Headscale) initOIDC() error {
|
|
var err error
|
|
// grab oidc config if it hasn't been already
|
|
if h.oauth2Config == nil {
|
|
h.oidcProvider, err = oidc.NewProvider(context.Background(), h.cfg.OIDC.Issuer)
|
|
|
|
if err != nil {
|
|
log.Error().
|
|
Err(err).
|
|
Caller().
|
|
Msgf("Could not retrieve OIDC Config: %s", err.Error())
|
|
|
|
return err
|
|
}
|
|
|
|
h.oauth2Config = &oauth2.Config{
|
|
ClientID: h.cfg.OIDC.ClientID,
|
|
ClientSecret: h.cfg.OIDC.ClientSecret,
|
|
Endpoint: h.oidcProvider.Endpoint(),
|
|
RedirectURL: fmt.Sprintf(
|
|
"%s/oidc/callback",
|
|
strings.TrimSuffix(h.cfg.ServerURL, "/"),
|
|
),
|
|
Scopes: h.cfg.OIDC.Scope,
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// RegisterOIDC redirects to the OIDC provider for authentication
|
|
// Puts machine key in cache so the callback can retrieve it using the oidc state param
|
|
// Listens in /oidc/register/:mKey.
|
|
func (h *Headscale) RegisterOIDC(
|
|
writer http.ResponseWriter,
|
|
req *http.Request,
|
|
) {
|
|
vars := mux.Vars(req)
|
|
machineKeyStr, ok := vars["mkey"]
|
|
if !ok || machineKeyStr == "" {
|
|
log.Error().
|
|
Caller().
|
|
Msg("Missing machine key in URL")
|
|
http.Error(writer, "Missing machine key in URL", http.StatusBadRequest)
|
|
|
|
return
|
|
}
|
|
|
|
log.Trace().
|
|
Caller().
|
|
Str("machine_key", machineKeyStr).
|
|
Msg("Received oidc register call")
|
|
|
|
randomBlob := make([]byte, randomByteSize)
|
|
if _, err := rand.Read(randomBlob); err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Msg("could not read 16 bytes from rand")
|
|
http.Error(writer, "Internal server error", http.StatusInternalServerError)
|
|
|
|
return
|
|
}
|
|
|
|
stateStr := hex.EncodeToString(randomBlob)[:32]
|
|
|
|
// place the machine key into the state cache, so it can be retrieved later
|
|
h.registrationCache.Set(stateStr, machineKeyStr, registerCacheExpiration)
|
|
|
|
// Add any extra parameter provided in the configuration to the Authorize Endpoint request
|
|
extras := make([]oauth2.AuthCodeOption, 0, len(h.cfg.OIDC.ExtraParams))
|
|
|
|
for k, v := range h.cfg.OIDC.ExtraParams {
|
|
extras = append(extras, oauth2.SetAuthURLParam(k, v))
|
|
}
|
|
|
|
authURL := h.oauth2Config.AuthCodeURL(stateStr, extras...)
|
|
log.Debug().Msgf("Redirecting to %s for authentication", authURL)
|
|
|
|
http.Redirect(writer, req, authURL, http.StatusFound)
|
|
}
|
|
|
|
type oidcCallbackTemplateConfig struct {
|
|
User string
|
|
Verb string
|
|
}
|
|
|
|
var oidcCallbackTemplate = template.Must(
|
|
template.New("oidccallback").Parse(`<html>
|
|
<body>
|
|
<h1>headscale</h1>
|
|
<p>
|
|
{{.Verb}} as {{.User}}, you can now close this window.
|
|
</p>
|
|
</body>
|
|
</html>`),
|
|
)
|
|
|
|
// OIDCCallback handles the callback from the OIDC endpoint
|
|
// Retrieves the mkey from the state cache and adds the machine to the users email namespace
|
|
// TODO: A confirmation page for new machines should be added to avoid phishing vulnerabilities
|
|
// TODO: Add groups information from OIDC tokens into machine HostInfo
|
|
// Listens in /oidc/callback.
|
|
func (h *Headscale) OIDCCallback(
|
|
writer http.ResponseWriter,
|
|
req *http.Request,
|
|
) {
|
|
code, state, err := validateOIDCCallbackParams(writer, req)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
rawIDToken, err := h.getIDTokenForOIDCCallback(writer, code, state)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
idToken, err := h.verifyIDTokenForOIDCCallback(writer, rawIDToken)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
// TODO: we can use userinfo at some point to grab additional information about the user (groups membership, etc)
|
|
// userInfo, err := oidcProvider.UserInfo(context.Background(), oauth2.StaticTokenSource(oauth2Token))
|
|
// if err != nil {
|
|
// c.String(http.StatusBadRequest, fmt.Sprintf("Failed to retrieve userinfo"))
|
|
// return
|
|
// }
|
|
|
|
claims, err := extractIDTokenClaims(writer, idToken)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
if err := validateOIDCAllowedDomains(writer, h.cfg.OIDC.AllowedDomains, claims); err != nil {
|
|
return
|
|
}
|
|
|
|
if err := validateOIDCAllowedUsers(writer, h.cfg.OIDC.AllowedUsers, claims); err != nil {
|
|
return
|
|
}
|
|
|
|
machineKey, machineExists, err := h.validateMachineForOIDCCallback(writer, state, claims)
|
|
if err != nil || machineExists {
|
|
return
|
|
}
|
|
|
|
namespaceName, err := getNamespaceName(writer, claims, h.cfg.OIDC.StripEmaildomain)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
// register the machine if it's new
|
|
log.Debug().Msg("Registering new machine after successful callback")
|
|
|
|
namespace, err := h.findOrCreateNewNamespaceForOIDCCallback(writer, namespaceName)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
if err := h.registerMachineForOIDCCallback(writer, namespace, machineKey); err != nil {
|
|
return
|
|
}
|
|
|
|
content, err := renderOIDCCallbackTemplate(writer, claims)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
writer.Header().Set("Content-Type", "text/html; charset=utf-8")
|
|
writer.WriteHeader(http.StatusOK)
|
|
if _, err := writer.Write(content.Bytes()); err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to write response")
|
|
}
|
|
}
|
|
|
|
func validateOIDCCallbackParams(
|
|
writer http.ResponseWriter,
|
|
req *http.Request,
|
|
) (string, string, error) {
|
|
code := req.URL.Query().Get("code")
|
|
state := req.URL.Query().Get("state")
|
|
|
|
if code == "" || state == "" {
|
|
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 "", "", errEmptyOIDCCallbackParams
|
|
}
|
|
|
|
return code, state, nil
|
|
}
|
|
|
|
func (h *Headscale) getIDTokenForOIDCCallback(
|
|
writer http.ResponseWriter,
|
|
code, state string,
|
|
) (string, error) {
|
|
oauth2Token, err := h.oauth2Config.Exchange(context.Background(), code)
|
|
if err != nil {
|
|
log.Error().
|
|
Err(err).
|
|
Caller().
|
|
Msg("Could not exchange code for token")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, werr := writer.Write([]byte("Could not exchange code for token"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return "", err
|
|
}
|
|
|
|
log.Trace().
|
|
Caller().
|
|
Str("code", code).
|
|
Str("state", state).
|
|
Msg("Got oidc callback")
|
|
|
|
rawIDToken, rawIDTokenOK := oauth2Token.Extra("id_token").(string)
|
|
if !rawIDTokenOK {
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, err := writer.Write([]byte("Could not extract ID Token"))
|
|
if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return "", errNoOIDCIDToken
|
|
}
|
|
|
|
return rawIDToken, nil
|
|
}
|
|
|
|
func (h *Headscale) verifyIDTokenForOIDCCallback(
|
|
writer http.ResponseWriter,
|
|
rawIDToken string,
|
|
) (*oidc.IDToken, error) {
|
|
verifier := h.oidcProvider.Verifier(&oidc.Config{ClientID: h.cfg.OIDC.ClientID})
|
|
idToken, err := verifier.Verify(context.Background(), rawIDToken)
|
|
if err != nil {
|
|
log.Error().
|
|
Err(err).
|
|
Caller().
|
|
Msg("failed to verify id token")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, werr := writer.Write([]byte("Failed to verify id token"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, err
|
|
}
|
|
|
|
return idToken, nil
|
|
}
|
|
|
|
func extractIDTokenClaims(
|
|
writer http.ResponseWriter,
|
|
idToken *oidc.IDToken,
|
|
) (*IDTokenClaims, error) {
|
|
var claims IDTokenClaims
|
|
if err := idToken.Claims(claims); err != nil {
|
|
log.Error().
|
|
Err(err).
|
|
Caller().
|
|
Msg("Failed to decode id token claims")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, werr := writer.Write([]byte("Failed to decode id token claims"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, err
|
|
}
|
|
|
|
return &claims, nil
|
|
}
|
|
|
|
// validateOIDCAllowedDomains checks that if AllowedDomains is provided,
|
|
// that the authenticated principal ends with @<alloweddomain>.
|
|
func validateOIDCAllowedDomains(
|
|
writer http.ResponseWriter,
|
|
allowedDomains []string,
|
|
claims *IDTokenClaims,
|
|
) error {
|
|
if len(allowedDomains) > 0 {
|
|
if at := strings.LastIndex(claims.Email, "@"); at < 0 ||
|
|
!IsStringInSlice(allowedDomains, claims.Email[at+1:]) {
|
|
log.Error().Msg("authenticated principal does not match any allowed domain")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, err := writer.Write([]byte("unauthorized principal (domain mismatch)"))
|
|
if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return errOIDCAllowedDomains
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// validateOIDCAllowedUsers checks that if AllowedUsers is provided,
|
|
// that the authenticated principal is part of that list.
|
|
func validateOIDCAllowedUsers(
|
|
writer http.ResponseWriter,
|
|
allowedUsers []string,
|
|
claims *IDTokenClaims,
|
|
) error {
|
|
if len(allowedUsers) > 0 &&
|
|
!IsStringInSlice(allowedUsers, claims.Email) {
|
|
log.Error().Msg("authenticated principal does not match any allowed user")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, err := writer.Write([]byte("unauthorized principal (user mismatch)"))
|
|
if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return errOIDCAllowedUsers
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// validateMachine retrieves 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.
|
|
func (h *Headscale) validateMachineForOIDCCallback(
|
|
writer http.ResponseWriter,
|
|
state string,
|
|
claims *IDTokenClaims,
|
|
) (*key.MachinePublic, bool, error) {
|
|
// retrieve machinekey from state cache
|
|
machineKeyIf, machineKeyFound := h.registrationCache.Get(state)
|
|
if !machineKeyFound {
|
|
log.Error().
|
|
Msg("requested machine state key expired before authorisation completed")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, err := writer.Write([]byte("state has expired"))
|
|
if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, false, errOIDCInvalidMachineState
|
|
}
|
|
|
|
var machineKey key.MachinePublic
|
|
machineKeyFromCache, machineKeyOK := machineKeyIf.(string)
|
|
err := machineKey.UnmarshalText(
|
|
[]byte(MachinePublicKeyEnsurePrefix(machineKeyFromCache)),
|
|
)
|
|
if err != nil {
|
|
log.Error().
|
|
Msg("could not parse machine public key")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusBadRequest)
|
|
_, werr := writer.Write([]byte("could not parse public key"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, false, err
|
|
}
|
|
|
|
if !machineKeyOK {
|
|
log.Error().Msg("could not get machine key from cache")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusInternalServerError)
|
|
_, err := writer.Write([]byte("could not get machine key from cache"))
|
|
if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, false, errOIDCMachineKeyMissing
|
|
}
|
|
|
|
// 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, reauthenticating")
|
|
|
|
err := h.RefreshMachine(machine, time.Time{})
|
|
if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to refresh machine")
|
|
http.Error(writer, "Failed to refresh machine", http.StatusInternalServerError)
|
|
|
|
return nil, true, err
|
|
}
|
|
|
|
var content bytes.Buffer
|
|
if err := oidcCallbackTemplate.Execute(&content, oidcCallbackTemplateConfig{
|
|
User: claims.Email,
|
|
Verb: "Reauthenticated",
|
|
}); err != nil {
|
|
log.Error().
|
|
Str("func", "OIDCCallback").
|
|
Str("type", "reauthenticate").
|
|
Err(err).
|
|
Msg("Could not render OIDC callback template")
|
|
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusInternalServerError)
|
|
_, werr := writer.Write([]byte("Could not render OIDC callback template"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, true, err
|
|
}
|
|
|
|
writer.Header().Set("Content-Type", "text/html; charset=utf-8")
|
|
writer.WriteHeader(http.StatusOK)
|
|
_, err = writer.Write(content.Bytes())
|
|
if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, true, nil
|
|
}
|
|
|
|
return &machineKey, false, nil
|
|
}
|
|
|
|
func getNamespaceName(
|
|
writer http.ResponseWriter,
|
|
claims *IDTokenClaims,
|
|
stripEmaildomain bool,
|
|
) (string, error) {
|
|
namespaceName, err := NormalizeToFQDNRules(
|
|
claims.Email,
|
|
stripEmaildomain,
|
|
)
|
|
if err != nil {
|
|
log.Error().Err(err).Caller().Msgf("couldn't normalize email")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusInternalServerError)
|
|
_, werr := writer.Write([]byte("couldn't normalize email"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return "", err
|
|
}
|
|
|
|
return namespaceName, nil
|
|
}
|
|
|
|
func (h *Headscale) findOrCreateNewNamespaceForOIDCCallback(
|
|
writer http.ResponseWriter,
|
|
namespaceName string,
|
|
) (*Namespace, error) {
|
|
namespace, err := h.GetNamespace(namespaceName)
|
|
if errors.Is(err, ErrNamespaceNotFound) {
|
|
namespace, err = h.CreateNamespace(namespaceName)
|
|
|
|
if err != nil {
|
|
log.Error().
|
|
Err(err).
|
|
Caller().
|
|
Msgf("could not create new namespace '%s'", namespaceName)
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusInternalServerError)
|
|
_, werr := writer.Write([]byte("could not create namespace"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, err
|
|
}
|
|
} else if err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Str("namespace", namespaceName).
|
|
Msg("could not find or create namespace")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusInternalServerError)
|
|
_, werr := writer.Write([]byte("could not find or create namespace"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, err
|
|
}
|
|
|
|
return namespace, nil
|
|
}
|
|
|
|
func (h *Headscale) registerMachineForOIDCCallback(
|
|
writer http.ResponseWriter,
|
|
namespace *Namespace,
|
|
machineKey *key.MachinePublic,
|
|
) error {
|
|
machineKeyStr := MachinePublicKeyStripPrefix(*machineKey)
|
|
|
|
if _, err := h.RegisterMachineFromAuthCallback(
|
|
machineKeyStr,
|
|
namespace.Name,
|
|
RegisterMethodOIDC,
|
|
); err != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(err).
|
|
Msg("could not register machine")
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusInternalServerError)
|
|
_, werr := writer.Write([]byte("could not register machine"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func renderOIDCCallbackTemplate(
|
|
writer http.ResponseWriter,
|
|
claims *IDTokenClaims,
|
|
) (*bytes.Buffer, error) {
|
|
var content bytes.Buffer
|
|
if err := oidcCallbackTemplate.Execute(&content, oidcCallbackTemplateConfig{
|
|
User: claims.Email,
|
|
Verb: "Authenticated",
|
|
}); err != nil {
|
|
log.Error().
|
|
Str("func", "OIDCCallback").
|
|
Str("type", "authenticate").
|
|
Err(err).
|
|
Msg("Could not render OIDC callback template")
|
|
|
|
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
|
|
writer.WriteHeader(http.StatusInternalServerError)
|
|
_, werr := writer.Write([]byte("Could not render OIDC callback template"))
|
|
if werr != nil {
|
|
log.Error().
|
|
Caller().
|
|
Err(werr).
|
|
Msg("Failed to write response")
|
|
}
|
|
|
|
return nil, err
|
|
}
|
|
|
|
return &content, nil
|
|
}
|