Docker CLI leaks private registry credentials to registry-1.docker.io

@@ -63,17 +63,14 @@ func RegistryAuthenticationPrivilegedFunc(cli Cli, index *registrytypes.IndexInf
 		indexServer := registry.GetAuthConfigKey(index)
 		isDefaultRegistry := indexServer == ElectAuthServer(context.Background(), cli)
 		authConfig, err := GetDefaultAuthConfig(cli, true, indexServer, isDefaultRegistry)
-		if authConfig == nil {
-			authConfig = &types.AuthConfig{}
-		}
 		if err != nil {
 			fmt.Fprintf(cli.Err(), "Unable to retrieve stored credentials for %s, error: %s.\n", indexServer, err)
 		}
-		err = ConfigureAuth(cli, "", "", authConfig, isDefaultRegistry)
+		err = ConfigureAuth(cli, "", "", &authConfig, isDefaultRegistry)
 		if err != nil {
 			return "", err
 		}
-		return EncodeAuthToBase64(*authConfig)
+		return EncodeAuthToBase64(authConfig)
 	}
 }
 
@@ -92,7 +89,7 @@ func ResolveAuthConfig(ctx context.Context, cli Cli, index *registrytypes.IndexI
 
 // GetDefaultAuthConfig gets the default auth config given a serverAddress
 // If credentials for given serverAddress exists in the credential store, the configuration will be populated with values in it
-func GetDefaultAuthConfig(cli Cli, checkCredStore bool, serverAddress string, isDefaultRegistry bool) (*types.AuthConfig, error) {
+func GetDefaultAuthConfig(cli Cli, checkCredStore bool, serverAddress string, isDefaultRegistry bool) (types.AuthConfig, error) {
 	if !isDefaultRegistry {
 		serverAddress = registry.ConvertToHostname(serverAddress)
 	}
@@ -101,13 +98,15 @@ func GetDefaultAuthConfig(cli Cli, checkCredStore bool, serverAddress string, is
 	if checkCredStore {
 		authconfig, err = cli.ConfigFile().GetAuthConfig(serverAddress)
 		if err != nil {
-			return nil, err
+			return types.AuthConfig{
+				ServerAddress: serverAddress,
+			}, err
 		}
 	}
 	authconfig.ServerAddress = serverAddress
 	authconfig.IdentityToken = ""
 	res := types.AuthConfig(authconfig)
-	return &res, nil
+	return res, nil
 }
 
 // ConfigureAuth handles prompting of user's username and password if needed

@@ -114,22 +114,19 @@ func runLogin(dockerCli command.Cli, opts loginOptions) error { //nolint: gocycl
 	var response registrytypes.AuthenticateOKBody
 	isDefaultRegistry := serverAddress == authServer
 	authConfig, err := command.GetDefaultAuthConfig(dockerCli, opts.user == "" && opts.password == "", serverAddress, isDefaultRegistry)
-	if authConfig == nil {
-		authConfig = &types.AuthConfig{}
-	}
 	if err == nil && authConfig.Username != "" && authConfig.Password != "" {
-		response, err = loginWithCredStoreCreds(ctx, dockerCli, authConfig)
+		response, err = loginWithCredStoreCreds(ctx, dockerCli, &authConfig)
 	}
 	if err != nil || authConfig.Username == "" || authConfig.Password == "" {
-		err = command.ConfigureAuth(dockerCli, opts.user, opts.password, authConfig, isDefaultRegistry)
+		err = command.ConfigureAuth(dockerCli, opts.user, opts.password, &authConfig, isDefaultRegistry)
 		if err != nil {
 			return err
 		}
 
-		response, err = clnt.RegistryLogin(ctx, *authConfig)
+		response, err = clnt.RegistryLogin(ctx, authConfig)
 		if err != nil && client.IsErrConnectionFailed(err) {
 			// If the server isn't responding (yet) attempt to login purely client side
-			response, err = loginClientSide(ctx, *authConfig)
+			response, err = loginClientSide(ctx, authConfig)
 		}
 		// If we (still) have an error, give up
 		if err != nil {
@@ -152,7 +149,7 @@ func runLogin(dockerCli command.Cli, opts loginOptions) error { //nolint: gocycl
 		}
 	}
 
-	if err := creds.Store(configtypes.AuthConfig(*authConfig)); err != nil {
+	if err := creds.Store(configtypes.AuthConfig(authConfig)); err != nil {
 		return errors.Errorf("Error saving credentials: %v", err)
 	}
 

@@ -145,7 +145,21 @@ func TestGetDefaultAuthConfig(t *testing.T) {
 			assert.Check(t, is.Equal(tc.expectedErr, err.Error()))
 		} else {
 			assert.NilError(t, err)
-			assert.Check(t, is.DeepEqual(tc.expectedAuthConfig, *authconfig))
+			assert.Check(t, is.DeepEqual(tc.expectedAuthConfig, authconfig))
 		}
 	}
 }
+
+func TestGetDefaultAuthConfig_HelperError(t *testing.T) {
+	cli := test.NewFakeCli(&fakeClient{})
+	errBuf := new(bytes.Buffer)
+	cli.SetErr(errBuf)
+	cli.ConfigFile().CredentialsStore = "fake-does-not-exist"
+	serverAddress := "test-server-address"
+	expectedAuthConfig := types.AuthConfig{
+		ServerAddress: serverAddress,
+	}
+	authconfig, err := GetDefaultAuthConfig(cli, true, serverAddress, serverAddress == "https://index.docker.io/v1/")
+	assert.Check(t, is.DeepEqual(expectedAuthConfig, authconfig))
+	assert.Check(t, is.ErrorContains(err, "docker-credential-fake-does-not-exist"))
+}