TUN-8960: Connect to FED API GW based on the OriginCert's endpoint

## Summary

Within the scope of the FEDRamp High RM, it is necessary to detect if an user should connect to a FEDRamp colo.

At first, it was considered to add the --fedramp as global flag however this could be a footgun for the user or even an hindrance, thus, the proposal is to save in the token (during login) if the user authenticated using the FEDRamp Dashboard. This solution makes it easier to the user as they will only be required to pass the flag in login and nothing else.

* Introduces the new field, endpoint, in OriginCert
* Refactors login to remove the private key and certificate which are no longer used
* Login will only store the Argo Tunnel Token
* Remove namedTunnelToken as it was only used to for serialization

Closes TUN-8960

Author: lmpn

cmd/cloudflared/flags/flags.go

@@ -149,4 +149,7 @@ const (
 
 	// MetricsUpdateFreq is the command line flag to define how frequently tunnel metrics are updated
 	MetricsUpdateFreq = "metrics-update-freq"
+
+	// ApiURL is the command line flag used to define the base URL of the API
+	ApiURL = "api-url"
 )

cmd/cloudflared/tail/cmd.go

@@ -23,9 +23,7 @@ import (
 	"github.com/cloudflare/cloudflared/management"
 )
 
-var (
-	buildInfo *cliutil.BuildInfo
-)
+var buildInfo *cliutil.BuildInfo
 
 func Init(bi *cliutil.BuildInfo) {
 	buildInfo = bi
@@ -56,7 +54,7 @@ func managementTokenCommand(c *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	var tokenResponse = struct {
+	tokenResponse := struct {
 		Token string `json:"token"`
 	}{Token: token}
 
@@ -231,7 +229,7 @@ func getManagementToken(c *cli.Context, log *zerolog.Logger) (string, error) {
 		return "", err
 	}
 
-	client, err := userCreds.Client(c.String("api-url"), buildInfo.UserAgent(), log)
+	client, err := userCreds.Client(c.String(cfdflags.ApiURL), buildInfo.UserAgent(), log)
 	if err != nil {
 		return "", err
 	}

cmd/cloudflared/tunnel/cmd.go

@@ -131,7 +131,7 @@ var (
 		"hostname",
 		"id",
 		cfdflags.LBPool,
-		"api-url",
+		cfdflags.ApiURL,
 		cfdflags.MetricsUpdateFreq,
 		cfdflags.Tag,
 		"heartbeat-interval",
@@ -716,7 +716,7 @@ func tunnelFlags(shouldHide bool) []cli.Flag {
 			Hidden:  true,
 		}),
 		altsrc.NewStringFlag(&cli.StringFlag{
-			Name:    "api-url",
+			Name:    cfdflags.ApiURL,
 			Usage:   "Base URL for Cloudflare API v4",
 			EnvVars: []string{"TUNNEL_API_URL"},
 			Value:   "https://api.cloudflare.com/client/v4",

cmd/cloudflared/tunnel/login.go

@@ -67,7 +67,7 @@ func login(c *cli.Context) error {
 
 	path, ok, err := checkForExistingCert()
 	if ok {
-		fmt.Fprintf(os.Stdout, "You have an existing certificate at %s which login would overwrite.\nIf this is intentional, please move or delete that file then run this command again.\n", path)
+		log.Error().Err(err).Msgf("You have an existing certificate at %s which login would overwrite.\nIf this is intentional, please move or delete that file then run this command again.\n", path)
 		return nil
 	} else if err != nil {
 		return err
@@ -78,7 +78,8 @@ func login(c *cli.Context) error {
 		callbackStoreURL = c.String(callbackURLParamName)
 	)
 
-	if c.Bool(fedRAMPParamName) {
+	isFEDRamp := c.Bool(fedRAMPParamName)
+	if isFEDRamp {
 		baseloginURL = fedBaseLoginURL
 		callbackStoreURL = fedCallbackStoreURL
 	}
@@ -99,15 +100,31 @@ func login(c *cli.Context) error {
 		log,
 	)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "Failed to write the certificate due to the following error:\n%v\n\nYour browser will download the certificate instead. You will have to manually\ncopy it to the following path:\n\n%s\n", err, path)
+		log.Error().Err(err).Msgf("Failed to write the certificate.\n\nYour browser will download the certificate instead. You will have to manually\ncopy it to the following path:\n\n%s\n", path)
+		return err
+	}
+
+	cert, err := credentials.DecodeOriginCert(resourceData)
+	if err != nil {
+		log.Error().Err(err).Msg("failed to decode origin certificate")
+		return err
+	}
+
+	if isFEDRamp {
+		cert.Endpoint = credentials.FedEndpoint
+	}
+
+	resourceData, err = cert.EncodeOriginCert()
+	if err != nil {
+		log.Error().Err(err).Msg("failed to encode origin certificate")
 		return err
 	}
 
 	if err := os.WriteFile(path, resourceData, 0600); err != nil {
 		return errors.Wrap(err, fmt.Sprintf("error writing cert to %s", path))
 	}
 
-	fmt.Fprintf(os.Stdout, "You have successfully logged in.\nIf you wish to copy your credentials to a server, they have been saved to:\n%s\n", path)
+	log.Info().Msgf("You have successfully logged in.\nIf you wish to copy your credentials to a server, they have been saved to:\n%s\n", path)
 	return nil
 }
 

cmd/cloudflared/tunnel/subcommand_context.go

@@ -20,6 +20,8 @@ import (
 	"github.com/cloudflare/cloudflared/logger"
 )
 
+const fedRampBaseApiURL = "https://api.fed.cloudflare.com/client/v4"
+
 type invalidJSONCredentialError struct {
 	err  error
 	path string
@@ -65,7 +67,16 @@ func (sc *subcommandContext) client() (cfapi.Client, error) {
 	if err != nil {
 		return nil, err
 	}
-	sc.tunnelstoreClient, err = cred.Client(sc.c.String("api-url"), buildInfo.UserAgent(), sc.log)
+
+	var apiURL string
+	if cred.IsFEDEndpoint() {
+		sc.log.Info().Str("api-url", fedRampBaseApiURL).Msg("using fedramp base api")
+		apiURL = fedRampBaseApiURL
+	} else {
+		apiURL = sc.c.String(cfdflags.ApiURL)
+	}
+
+	sc.tunnelstoreClient, err = cred.Client(apiURL, buildInfo.UserAgent(), sc.log)
 	if err != nil {
 		return nil, err
 	}

credentials/credentials.go

@@ -9,6 +9,7 @@ import (
 
 const (
 	logFieldOriginCertPath = "originCertPath"
+	FedEndpoint            = "fed"
 )
 
 type User struct {
@@ -32,6 +33,10 @@ func (c User) CertPath() string {
 	return c.certPath
 }
 
+func (c User) IsFEDEndpoint() bool {
+	return c.cert.Endpoint == FedEndpoint
+}
+
 // Client uses the user credentials to create a Cloudflare API client
 func (c *User) Client(apiURL string, userAgent string, log *zerolog.Logger) (cfapi.Client, error) {
 	if apiURL == "" {
@@ -45,7 +50,6 @@ func (c *User) Client(apiURL string, userAgent string, log *zerolog.Logger) (cfa
 		userAgent,
 		log,
 	)
-
 	if err != nil {
 		return nil, err
 	}

credentials/origin_cert.go

@@ -1,11 +1,13 @@
 package credentials
 
 import (
+	"bytes"
 	"encoding/json"
 	"encoding/pem"
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/mitchellh/go-homedir"
 	"github.com/rs/zerolog"
@@ -17,16 +19,28 @@ const (
 	DefaultCredentialFile = "cert.pem"
 )
 
-type namedTunnelToken struct {
+type OriginCert struct {
 	ZoneID    string `json:"zoneID"`
 	AccountID string `json:"accountID"`
 	APIToken  string `json:"apiToken"`
+	Endpoint  string `json:"endpoint,omitempty"`
 }
 
-type OriginCert struct {
-	ZoneID    string
-	APIToken  string
-	AccountID string
+func (oc *OriginCert) UnmarshalJSON(data []byte) error {
+	var aux struct {
+		ZoneID    string `json:"zoneID"`
+		AccountID string `json:"accountID"`
+		APIToken  string `json:"apiToken"`
+		Endpoint  string `json:"endpoint,omitempty"`
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return fmt.Errorf("error parsing OriginCert: %v", err)
+	}
+	oc.ZoneID = aux.ZoneID
+	oc.AccountID = aux.AccountID
+	oc.APIToken = aux.APIToken
+	oc.Endpoint = strings.ToLower(aux.Endpoint)
+	return nil
 }
 
 // FindDefaultOriginCertPath returns the first path that contains a cert.pem file. If none of the
@@ -41,40 +55,56 @@ func FindDefaultOriginCertPath() string {
 	return ""
 }
 
+func DecodeOriginCert(blocks []byte) (*OriginCert, error) {
+	return decodeOriginCert(blocks)
+}
+
+func (cert *OriginCert) EncodeOriginCert() ([]byte, error) {
+	if cert == nil {
+		return nil, fmt.Errorf("originCert cannot be nil")
+	}
+	buffer, err := json.Marshal(cert)
+	if err != nil {
+		return nil, fmt.Errorf("originCert marshal failed: %v", err)
+	}
+	block := pem.Block{
+		Type:    "ARGO TUNNEL TOKEN",
+		Headers: map[string]string{},
+		Bytes:   buffer,
+	}
+	var out bytes.Buffer
+	err = pem.Encode(&out, &block)
+	if err != nil {
+		return nil, fmt.Errorf("pem encoding failed: %v", err)
+	}
+	return out.Bytes(), nil
+}
+
 func decodeOriginCert(blocks []byte) (*OriginCert, error) {
 	if len(blocks) == 0 {
-		return nil, fmt.Errorf("Cannot decode empty certificate")
+		return nil, fmt.Errorf("cannot decode empty certificate")
 	}
 	originCert := OriginCert{}
 	block, rest := pem.Decode(blocks)
-	for {
-		if block == nil {
-			break
-		}
+	for block != nil {
 		switch block.Type {
 		case "PRIVATE KEY", "CERTIFICATE":
 			// this is for legacy purposes.
-			break
 		case "ARGO TUNNEL TOKEN":
 			if originCert.ZoneID != "" || originCert.APIToken != "" {
-				return nil, fmt.Errorf("Found multiple tokens in the certificate")
+				return nil, fmt.Errorf("found multiple tokens in the certificate")
 			}
 			// The token is a string,
 			// Try the newer JSON format
-			ntt := namedTunnelToken{}
-			if err := json.Unmarshal(block.Bytes, &ntt); err == nil {
-				originCert.ZoneID = ntt.ZoneID
-				originCert.APIToken = ntt.APIToken
-				originCert.AccountID = ntt.AccountID
-			}
+			_ = json.Unmarshal(block.Bytes, &originCert)
 		default:
-			return nil, fmt.Errorf("Unknown block %s in the certificate", block.Type)
+			return nil, fmt.Errorf("unknown block %s in the certificate", block.Type)
 		}
 		block, rest = pem.Decode(rest)
 	}
 
 	if originCert.ZoneID == "" || originCert.APIToken == "" {
-		return nil, fmt.Errorf("Missing token in the certificate")
+		return nil, fmt.Errorf("missing token in the certificate")
 	}
 
 	return &originCert, nil

credentials/origin_cert_test.go

@@ -16,27 +16,25 @@ const (
 	originCertFile = "cert.pem"
 )
 
-var (
-	nopLog = zerolog.Nop().With().Logger()
-)
+var nopLog = zerolog.Nop().With().Logger()
 
 func TestLoadOriginCert(t *testing.T) {
 	cert, err := decodeOriginCert([]byte{})
-	assert.Equal(t, fmt.Errorf("Cannot decode empty certificate"), err)
+	assert.Equal(t, fmt.Errorf("cannot decode empty certificate"), err)
 	assert.Nil(t, cert)
 
 	blocks, err := os.ReadFile("test-cert-unknown-block.pem")
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	cert, err = decodeOriginCert(blocks)
-	assert.Equal(t, fmt.Errorf("Unknown block RSA PRIVATE KEY in the certificate"), err)
+	assert.Equal(t, fmt.Errorf("unknown block RSA PRIVATE KEY in the certificate"), err)
 	assert.Nil(t, cert)
 }
 
 func TestJSONArgoTunnelTokenEmpty(t *testing.T) {
 	blocks, err := os.ReadFile("test-cert-no-token.pem")
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	cert, err := decodeOriginCert(blocks)
-	assert.Equal(t, fmt.Errorf("Missing token in the certificate"), err)
+	assert.Equal(t, fmt.Errorf("missing token in the certificate"), err)
 	assert.Nil(t, cert)
 }
 
@@ -52,51 +50,21 @@ func TestJSONArgoTunnelToken(t *testing.T) {
 
 func CloudflareTunnelTokenTest(t *testing.T, path string) {
 	blocks, err := os.ReadFile(path)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	cert, err := decodeOriginCert(blocks)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	assert.NotNil(t, cert)
 	assert.Equal(t, "7b0a4d77dfb881c1a3b7d61ea9443e19", cert.ZoneID)
 	key := "test-service-key"
 	assert.Equal(t, key, cert.APIToken)
 }
 
-type mockFile struct {
-	path string
-	data []byte
-	err  error
-}
-
-type mockFileSystem struct {
-	files map[string]mockFile
-}
-
-func newMockFileSystem(files ...mockFile) *mockFileSystem {
-	fs := mockFileSystem{map[string]mockFile{}}
-	for _, f := range files {
-		fs.files[f.path] = f
-	}
-	return &fs
-}
-
-func (fs *mockFileSystem) ReadFile(path string) ([]byte, error) {
-	if f, ok := fs.files[path]; ok {
-		return f.data, f.err
-	}
-	return nil, os.ErrNotExist
-}
-
-func (fs *mockFileSystem) ValidFilePath(path string) bool {
-	_, exists := fs.files[path]
-	return exists
-}
-
 func TestFindOriginCert_Valid(t *testing.T) {
 	file, err := os.ReadFile("test-cloudflare-tunnel-cert-json.pem")
 	require.NoError(t, err)
 	dir := t.TempDir()
 	certPath := path.Join(dir, originCertFile)
-	os.WriteFile(certPath, file, fs.ModePerm)
+	_ = os.WriteFile(certPath, file, fs.ModePerm)
 	path, err := FindOriginCert(certPath, &nopLog)
 	require.NoError(t, err)
 	require.Equal(t, certPath, path)
@@ -108,3 +76,28 @@ func TestFindOriginCert_Missing(t *testing.T) {
 	_, err := FindOriginCert(certPath, &nopLog)
 	require.Error(t, err)
 }
+
+func TestEncodeDecodeOriginCert(t *testing.T) {
+	cert := OriginCert{
+		ZoneID:    "zone",
+		AccountID: "account",
+		APIToken:  "token",
+		Endpoint:  "FED",
+	}
+	blocks, err := cert.EncodeOriginCert()
+	require.NoError(t, err)
+	decodedCert, err := DecodeOriginCert(blocks)
+	require.NoError(t, err)
+	assert.NotNil(t, cert)
+	assert.Equal(t, "zone", decodedCert.ZoneID)
+	assert.Equal(t, "account", decodedCert.AccountID)
+	assert.Equal(t, "token", decodedCert.APIToken)
+	assert.Equal(t, FedEndpoint, decodedCert.Endpoint)
+}
+
+func TestEncodeDecodeNilOriginCert(t *testing.T) {
+	var cert *OriginCert
+	blocks, err := cert.EncodeOriginCert()
+	assert.Equal(t, fmt.Errorf("originCert cannot be nil"), err)
+	require.Nil(t, blocks)
+}