cloudflared-mirror/token/transfer.go

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package token
import (
"bytes"
"encoding/base64"
"fmt"
"io"
"net/http"
"net/url"
"os"
"time"
"github.com/pkg/errors"
"github.com/rs/zerolog"
)
const (
baseStoreURL = "https://login.cloudflareaccess.org/"
clientTimeout = time.Second * 60
)
// RunTransfer does the transfer "dance" with the end result downloading the supported resource.
// The expanded description is run is encapsulation of shared business logic needed
// to request a resource (token/cert/etc) from the transfer service (loginhelper).
// The "dance" we refer to is building a HTTP request, opening that in a browser waiting for
// the user to complete an action, while it long polls in the background waiting for an
// action to be completed to download the resource.
func RunTransfer(transferURL *url.URL, resourceName, key, value string, shouldEncrypt bool, useHostOnly bool, log *zerolog.Logger) ([]byte, error) {
encrypterClient, err := NewEncrypter("cloudflared_priv.pem", "cloudflared_pub.pem")
if err != nil {
return nil, err
}
requestURL, err := buildRequestURL(transferURL, key, value+encrypterClient.PublicKey(), shouldEncrypt, useHostOnly)
if err != nil {
return nil, err
}
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// See AUTH-1423 for why we use stderr (the way git wraps ssh)
err = OpenBrowser(requestURL)
if err != nil {
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fmt.Fprintf(os.Stderr, "Please open the following URL and log in with your Cloudflare account:\n\n%s\n\nLeave cloudflared running to download the %s automatically.\n", requestURL, resourceName)
} else {
fmt.Fprintf(os.Stderr, "A browser window should have opened at the following URL:\n\n%s\n\nIf the browser failed to open, please visit the URL above directly in your browser.\n", requestURL)
}
var resourceData []byte
if shouldEncrypt {
buf, key, err := transferRequest(baseStoreURL+"transfer/"+encrypterClient.PublicKey(), log)
if err != nil {
return nil, err
}
decodedBuf, err := base64.StdEncoding.DecodeString(string(buf))
if err != nil {
return nil, err
}
decrypted, err := encrypterClient.Decrypt(decodedBuf, key)
if err != nil {
return nil, err
}
resourceData = decrypted
} else {
buf, _, err := transferRequest(baseStoreURL+encrypterClient.PublicKey(), log)
if err != nil {
return nil, err
}
resourceData = buf
}
return resourceData, nil
}
// BuildRequestURL creates a request suitable for a resource transfer.
// it will return a constructed url based off the base url and query key/value provided.
// cli will build a url for cli transfer request.
func buildRequestURL(baseURL *url.URL, key, value string, cli, useHostOnly bool) (string, error) {
q := baseURL.Query()
q.Set(key, value)
baseURL.RawQuery = q.Encode()
if useHostOnly {
baseURL.Path = ""
}
// TODO: pass arg for tunnel login
if !cli {
return baseURL.String(), nil
}
q.Set("redirect_url", baseURL.String()) // we add the token as a query param on both the redirect_url and the main url
q.Set("send_org_token", "true") // indicates that the cli endpoint should return both the org and app token
q.Set("edge_token_transfer", "true") // use new LoginHelper service built on workers
baseURL.RawQuery = q.Encode() // and this actual baseURL.
baseURL.Path = "cdn-cgi/access/cli"
return baseURL.String(), nil
}
// transferRequest downloads the requested resource from the request URL
func transferRequest(requestURL string, log *zerolog.Logger) ([]byte, string, error) {
client := &http.Client{Timeout: clientTimeout}
const pollAttempts = 10
// we do "long polling" on the endpoint to get the resource.
for i := 0; i < pollAttempts; i++ {
buf, key, err := poll(client, requestURL, log)
if err != nil {
return nil, "", err
} else if len(buf) > 0 {
return buf, key, nil
}
}
return nil, "", errors.New("Failed to fetch resource")
}
// poll the endpoint for the request resource, waiting for the user interaction
func poll(client *http.Client, requestURL string, log *zerolog.Logger) ([]byte, string, error) {
resp, err := client.Get(requestURL)
if err != nil {
return nil, "", err
}
defer resp.Body.Close()
// ignore everything other than server errors as the resource
// may not exist until the user does the interaction
if resp.StatusCode >= 500 {
return nil, "", fmt.Errorf("error on request %d", resp.StatusCode)
}
if resp.StatusCode != 200 {
log.Info().Msg("Waiting for login...")
return nil, "", nil
}
buf := new(bytes.Buffer)
if _, err := io.Copy(buf, resp.Body); err != nil {
return nil, "", err
}
return buf.Bytes(), resp.Header.Get("service-public-key"), nil
}