Create basic webhook for SCEP challenge validation
Herman Slatman
1 year ago
parent
1420c762e0
commit
05f7ab979f
@ -0,0 +1,24 @@
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package webhook
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type ControllerOption func(*Controller) error
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func WithURL(url string) ControllerOption {
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return func(c *Controller) error {
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c.webhook.URL = url
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return nil
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}
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}
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func WithBearerToken(token string) ControllerOption {
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return func(c *Controller) error {
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c.webhook.BearerToken = token
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return nil
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}
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}
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func WithDisableTLSClientAuth(enabled bool) ControllerOption {
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return func(c *Controller) error {
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c.webhook.DisableTLSClientAuth = enabled
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return nil
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}
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}
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@ -0,0 +1,161 @@
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package webhook
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import (
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"bytes"
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"context"
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"crypto/hmac"
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"crypto/sha256"
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"encoding/base64"
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"encoding/hex"
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"encoding/json"
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"errors"
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"fmt"
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"log"
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"net/http"
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"time"
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"github.com/ryboe/q"
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)
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type Controller struct {
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client *http.Client
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webhook *Webhook
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}
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func New(options ...ControllerOption) (*Controller, error) {
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c := &Controller{
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client: http.DefaultClient,
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webhook: &Webhook{},
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}
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for _, apply := range options {
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if err := apply(c); err != nil {
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return nil, err
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}
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}
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return c, nil
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}
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func (c *Controller) Validate(challenge string) (bool, error) {
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req := &Request{
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Challenge: challenge,
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}
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client := c.client
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if client == nil {
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client = http.DefaultClient
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}
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resp, err := c.webhook.Do(client, req)
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if err != nil {
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q.Q(err)
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return false, fmt.Errorf("failed performing webhook request: %w", err)
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}
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if resp == nil {
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return false, nil
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}
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return true, nil
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}
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type Webhook struct {
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URL string
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DisableTLSClientAuth bool
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Secret string
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BearerToken string
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BasicAuth struct {
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Username string
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Password string
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}
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}
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func (w *Webhook) Do(client *http.Client, req *Request) (*Response, error) {
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ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
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defer cancel()
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reqBytes, err := json.Marshal(req)
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if err != nil {
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return nil, err
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}
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retries := 1
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retry:
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r, err := http.NewRequestWithContext(ctx, "POST", w.URL, bytes.NewReader(reqBytes))
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if err != nil {
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return nil, err
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}
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if w.Secret != "" {
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secret, err := base64.StdEncoding.DecodeString(w.Secret)
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if err != nil {
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return nil, err
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}
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sig := hmac.New(sha256.New, secret).Sum(reqBytes)
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r.Header.Set("X-Smallstep-Signature", hex.EncodeToString(sig))
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//req.Header.Set("X-Smallstep-Webhook-ID", w.ID)
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}
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if w.BearerToken != "" {
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r.Header.Set("Authorization", fmt.Sprintf("Bearer %s", w.BearerToken))
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} else if w.BasicAuth.Username != "" || w.BasicAuth.Password != "" {
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r.SetBasicAuth(w.BasicAuth.Username, w.BasicAuth.Password)
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}
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if w.DisableTLSClientAuth {
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transport, ok := client.Transport.(*http.Transport)
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if !ok {
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return nil, errors.New("client transport is not a *http.Transport")
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}
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transport = transport.Clone()
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tlsConfig := transport.TLSClientConfig.Clone()
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tlsConfig.GetClientCertificate = nil
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tlsConfig.Certificates = nil
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transport.TLSClientConfig = tlsConfig
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client = &http.Client{
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Transport: transport,
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}
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}
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resp, err := client.Do(r)
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if err != nil {
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if errors.Is(err, context.DeadlineExceeded) {
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return nil, err
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} else if retries > 0 {
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retries--
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time.Sleep(time.Second)
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goto retry
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}
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return nil, err
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}
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defer func() {
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if err := resp.Body.Close(); err != nil {
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// TODO: return this error instead of (just) logging?
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log.Printf("failed to close body of response from %s", w.URL)
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}
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}()
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if resp.StatusCode >= 500 && retries > 0 {
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retries--
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time.Sleep(time.Second)
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goto retry
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}
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if resp.StatusCode >= 400 {
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return nil, fmt.Errorf("webhook server responded with %d", resp.StatusCode)
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}
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respBody := &Response{}
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// TODO: decide on the JSON structure for the response (if any); HTTP status code may be enough.
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// if err := json.NewDecoder(resp.Body).Decode(respBody); err != nil {
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// return nil, err
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// }
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return respBody, nil
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}
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type Request struct {
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Challenge string `json:"challenge"`
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}
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type Response struct {
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// TODO: define expected response format? Or do we consider 200 OK enough?
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Allow bool `json:"allow"`
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}
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