Merge pull request #20107 from calavera/client_auth_store

Client credentials store.

api/client/cli.go

@@ -11,6 +11,7 @@ import (
 	"github.com/docker/docker/api"
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cliconfig"
+	"github.com/docker/docker/cliconfig/credentials"
 	"github.com/docker/docker/dockerversion"
 	"github.com/docker/docker/opts"
 	"github.com/docker/docker/pkg/term"
@@ -125,6 +126,9 @@ func NewDockerCli(in io.ReadCloser, out, err io.Writer, clientFlags *cli.ClientF
 		if e != nil {
 			fmt.Fprintf(cli.err, "WARNING: Error loading config file:%v\n", e)
 		}
+		if !configFile.ContainsAuth() {
+			credentials.DetectDefaultStore(configFile)
+		}
 		cli.configFile = configFile
 
 		host, err := getServerHost(clientFlags.Common.Hosts, clientFlags.Common.TLSOptions)

api/client/create.go

@@ -42,7 +42,7 @@ func (cli *DockerCli) pullImageCustomOut(image string, out io.Writer) error {
 		return err
 	}
 
-	authConfig := cli.resolveAuthConfig(cli.configFile.AuthConfigs, repoInfo.Index)
+	authConfig := cli.resolveAuthConfig(repoInfo.Index)
 	encodedAuth, err := encodeAuthToBase64(authConfig)
 	if err != nil {
 		return err

api/client/login.go

@@ -9,6 +9,8 @@ import (
 	"strings"
 
 	Cli "github.com/docker/docker/cli"
+	"github.com/docker/docker/cliconfig"
+	"github.com/docker/docker/cliconfig/credentials"
 	flag "github.com/docker/docker/pkg/mflag"
 	"github.com/docker/docker/pkg/term"
 	"github.com/docker/engine-api/client"
@@ -50,18 +52,16 @@ func (cli *DockerCli) CmdLogin(args ...string) error {
 	response, err := cli.client.RegistryLogin(authConfig)
 	if err != nil {
 		if client.IsErrUnauthorized(err) {
-			delete(cli.configFile.AuthConfigs, serverAddress)
-			if err2 := cli.configFile.Save(); err2 != nil {
-				fmt.Fprintf(cli.out, "WARNING: could not save config file: %v\n", err2)
+			if err2 := eraseCredentials(cli.configFile, authConfig.ServerAddress); err2 != nil {
+				fmt.Fprintf(cli.out, "WARNING: could not save credentials: %v\n", err2)
 			}
 		}
 		return err
 	}
 
-	if err := cli.configFile.Save(); err != nil {
-		return fmt.Errorf("Error saving config file: %v", err)
+	if err := storeCredentials(cli.configFile, authConfig); err != nil {
+		return fmt.Errorf("Error saving credentials: %v", err)
 	}
-	fmt.Fprintf(cli.out, "WARNING: login credentials saved in %s\n", cli.configFile.Filename())
 
 	if response.Status != "" {
 		fmt.Fprintf(cli.out, "%s\n", response.Status)
@@ -78,10 +78,11 @@ func (cli *DockerCli) promptWithDefault(prompt string, configDefault string) {
 }
 
 func (cli *DockerCli) configureAuth(flUser, flPassword, flEmail, serverAddress string) (types.AuthConfig, error) {
-	authconfig, ok := cli.configFile.AuthConfigs[serverAddress]
-	if !ok {
-		authconfig = types.AuthConfig{}
+	authconfig, err := getCredentials(cli.configFile, serverAddress)
+	if err != nil {
+		return authconfig, err
 	}
+
 	authconfig.Username = strings.TrimSpace(authconfig.Username)
 
 	if flUser = strings.TrimSpace(flUser); flUser == "" {
@@ -133,11 +134,12 @@ func (cli *DockerCli) configureAuth(flUser, flPassword, flEmail, serverAddress s
 			flEmail = authconfig.Email
 		}
 	}
+
 	authconfig.Username = flUser
 	authconfig.Password = flPassword
 	authconfig.Email = flEmail
 	authconfig.ServerAddress = serverAddress
-	cli.configFile.AuthConfigs[serverAddress] = authconfig
+
 	return authconfig, nil
 }
 
@@ -150,3 +152,33 @@ func readInput(in io.Reader, out io.Writer) string {
 	}
 	return string(line)
 }
+
+// getCredentials loads the user credentials from a credentials store.
+// The store is determined by the config file settings.
+func getCredentials(c *cliconfig.ConfigFile, serverAddress string) (types.AuthConfig, error) {
+	s := loadCredentialsStore(c)
+	return s.Get(serverAddress)
+}
+
+// storeCredentials saves the user credentials in a credentials store.
+// The store is determined by the config file settings.
+func storeCredentials(c *cliconfig.ConfigFile, auth types.AuthConfig) error {
+	s := loadCredentialsStore(c)
+	return s.Store(auth)
+}
+
+// eraseCredentials removes the user credentials from a credentials store.
+// The store is determined by the config file settings.
+func eraseCredentials(c *cliconfig.ConfigFile, serverAddress string) error {
+	s := loadCredentialsStore(c)
+	return s.Erase(serverAddress)
+}
+
+// loadCredentialsStore initializes a new credentials store based
+// in the settings provided in the configuration file.
+func loadCredentialsStore(c *cliconfig.ConfigFile) credentials.Store {
+	if c.CredentialsStore != "" {
+		return credentials.NewNativeStore(c)
+	}
+	return credentials.NewFileStore(c)
+}

api/client/pull.go

@@ -56,7 +56,7 @@ func (cli *DockerCli) CmdPull(args ...string) error {
 		return err
 	}
 
-	authConfig := cli.resolveAuthConfig(cli.configFile.AuthConfigs, repoInfo.Index)
+	authConfig := cli.resolveAuthConfig(repoInfo.Index)
 	requestPrivilege := cli.registryAuthenticationPrivilegedFunc(repoInfo.Index, "pull")
 
 	if isTrusted() && !ref.HasDigest() {

api/client/push.go

@@ -44,7 +44,7 @@ func (cli *DockerCli) CmdPush(args ...string) error {
 		return err
 	}
 	// Resolve the Auth config relevant for this server
-	authConfig := cli.resolveAuthConfig(cli.configFile.AuthConfigs, repoInfo.Index)
+	authConfig := cli.resolveAuthConfig(repoInfo.Index)
 
 	requestPrivilege := cli.registryAuthenticationPrivilegedFunc(repoInfo.Index, "push")
 	if isTrusted() {

api/client/search.go

@@ -36,7 +36,7 @@ func (cli *DockerCli) CmdSearch(args ...string) error {
 		return err
 	}
 
-	authConfig := cli.resolveAuthConfig(cli.configFile.AuthConfigs, indexInfo)
+	authConfig := cli.resolveAuthConfig(indexInfo)
 	requestPrivilege := cli.registryAuthenticationPrivilegedFunc(indexInfo, "search")
 
 	encodedAuth, err := encodeAuthToBase64(authConfig)

api/client/trust.go

@@ -238,7 +238,7 @@ func (cli *DockerCli) trustedReference(ref reference.NamedTagged) (reference.Can
 	}
 
 	// Resolve the Auth config relevant for this server
-	authConfig := cli.resolveAuthConfig(cli.configFile.AuthConfigs, repoInfo.Index)
+	authConfig := cli.resolveAuthConfig(repoInfo.Index)
 
 	notaryRepo, err := cli.getNotaryRepository(repoInfo, authConfig)
 	if err != nil {

api/client/utils.go

@@ -10,7 +10,6 @@ import (
 	gosignal "os/signal"
 	"path/filepath"
 	"runtime"
-	"strings"
 	"time"
 
 	"github.com/Sirupsen/logrus"
@@ -185,38 +184,12 @@ func copyToFile(outfile string, r io.Reader) error {
 // resolveAuthConfig is like registry.ResolveAuthConfig, but if using the
 // default index, it uses the default index name for the daemon's platform,
 // not the client's platform.
-func (cli *DockerCli) resolveAuthConfig(authConfigs map[string]types.AuthConfig, index *registrytypes.IndexInfo) types.AuthConfig {
+func (cli *DockerCli) resolveAuthConfig(index *registrytypes.IndexInfo) types.AuthConfig {
 	configKey := index.Name
 	if index.Official {
 		configKey = cli.electAuthServer()
 	}
 
-	// First try the happy case
-	if c, found := authConfigs[configKey]; found || index.Official {
-		return c
-	}
-
-	convertToHostname := func(url string) string {
-		stripped := url
-		if strings.HasPrefix(url, "http://") {
-			stripped = strings.Replace(url, "http://", "", 1)
-		} else if strings.HasPrefix(url, "https://") {
-			stripped = strings.Replace(url, "https://", "", 1)
-		}
-
-		nameParts := strings.SplitN(stripped, "/", 2)
-
-		return nameParts[0]
-	}
-
-	// Maybe they have a legacy config file, we will iterate the keys converting
-	// them to the new format and testing
-	for registry, ac := range authConfigs {
-		if configKey == convertToHostname(registry) {
-			return ac
-		}
-	}
-
-	// When all else fails, return an empty auth config
-	return types.AuthConfig{}
+	a, _ := getCredentials(cli.configFile, configKey)
+	return a
 }

cliconfig/config.go

@@ -48,12 +48,13 @@ func SetConfigDir(dir string) {
 
 // ConfigFile ~/.docker/config.json file info
 type ConfigFile struct {
-	AuthConfigs  map[string]types.AuthConfig `json:"auths"`
-	HTTPHeaders  map[string]string           `json:"HttpHeaders,omitempty"`
-	PsFormat     string                      `json:"psFormat,omitempty"`
-	ImagesFormat string                      `json:"imagesFormat,omitempty"`
-	DetachKeys   string                      `json:"detachKeys,omitempty"`
-	filename     string                      // Note: not serialized - for internal use only
+	AuthConfigs      map[string]types.AuthConfig `json:"auths"`
+	HTTPHeaders      map[string]string           `json:"HttpHeaders,omitempty"`
+	PsFormat         string                      `json:"psFormat,omitempty"`
+	ImagesFormat     string                      `json:"imagesFormat,omitempty"`
+	DetachKeys       string                      `json:"detachKeys,omitempty"`
+	CredentialsStore string                      `json:"credsStore,omitempty"`
+	filename         string                      // Note: not serialized - for internal use only
 }
 
 // NewConfigFile initializes an empty configuration file for the given filename 'fn'
@@ -127,6 +128,13 @@ func (configFile *ConfigFile) LoadFromReader(configData io.Reader) error {
 	return nil
 }
 
+// ContainsAuth returns whether there is authentication configured
+// in this file or not.
+func (configFile *ConfigFile) ContainsAuth() bool {
+	return configFile.CredentialsStore != "" ||
+		(configFile.AuthConfigs != nil && len(configFile.AuthConfigs) > 0)
+}
+
 // LegacyLoadFromReader is a convenience function that creates a ConfigFile object from
 // a non-nested reader
 func LegacyLoadFromReader(configData io.Reader) (*ConfigFile, error) {
@@ -250,6 +258,10 @@ func (configFile *ConfigFile) Filename() string {
 
 // encodeAuth creates a base64 encoded string to containing authorization information
 func encodeAuth(authConfig *types.AuthConfig) string {
+	if authConfig.Username == "" && authConfig.Password == "" {
+		return ""
+	}
+
 	authStr := authConfig.Username + ":" + authConfig.Password
 	msg := []byte(authStr)
 	encoded := make([]byte, base64.StdEncoding.EncodedLen(len(msg)))
@@ -259,6 +271,10 @@ func encodeAuth(authConfig *types.AuthConfig) string {
 
 // decodeAuth decodes a base64 encoded string and returns username and password
 func decodeAuth(authStr string) (string, string, error) {
+	if authStr == "" {
+		return "", "", nil
+	}
+
 	decLen := base64.StdEncoding.DecodedLen(len(authStr))
 	decoded := make([]byte, decLen)
 	authByte := []byte(authStr)

cliconfig/credentials/credentials.go

@@ -0,0 +1,15 @@
+package credentials
+
+import (
+	"github.com/docker/engine-api/types"
+)
+
+// Store is the interface that any credentials store must implement.
+type Store interface {
+	// Erase removes credentials from the store for a given server.
+	Erase(serverAddress string) error
+	// Get retrieves credentials from the store for a given server.
+	Get(serverAddress string) (types.AuthConfig, error)
+	// Store saves credentials in the store.
+	Store(authConfig types.AuthConfig) error
+}

cliconfig/credentials/default_store_darwin.go

@@ -0,0 +1,22 @@
+package credentials
+
+import (
+	"os/exec"
+
+	"github.com/docker/docker/cliconfig"
+)
+
+const defaultCredentialsStore = "osxkeychain"
+
+// DetectDefaultStore sets the default credentials store
+// if the host includes the default store helper program.
+func DetectDefaultStore(c *cliconfig.ConfigFile) {
+	if c.CredentialsStore != "" {
+		// user defined
+		return
+	}
+
+	if _, err := exec.LookPath(remoteCredentialsPrefix + c.CredentialsStore); err == nil {
+		c.CredentialsStore = defaultCredentialsStore
+	}
+}

cliconfig/credentials/default_store_unsupported.go

@@ -0,0 +1,11 @@
+// +build !darwin
+
+package credentials
+
+import "github.com/docker/docker/cliconfig"
+
+// DetectDefaultStore sets the default credentials store
+// if the host includes the default store helper program.
+// This operation is only supported in Darwin.
+func DetectDefaultStore(c *cliconfig.ConfigFile) {
+}

cliconfig/credentials/file_store.go

@@ -0,0 +1,63 @@
+package credentials
+
+import (
+	"strings"
+
+	"github.com/docker/docker/cliconfig"
+	"github.com/docker/engine-api/types"
+)
+
+// fileStore implements a credentials store using
+// the docker configuration file to keep the credentials in plain text.
+type fileStore struct {
+	file *cliconfig.ConfigFile
+}
+
+// NewFileStore creates a new file credentials store.
+func NewFileStore(file *cliconfig.ConfigFile) Store {
+	return &fileStore{
+		file: file,
+	}
+}
+
+// Erase removes the given credentials from the file store.
+func (c *fileStore) Erase(serverAddress string) error {
+	delete(c.file.AuthConfigs, serverAddress)
+	return c.file.Save()
+}
+
+// Get retrieves credentials for a specific server from the file store.
+func (c *fileStore) Get(serverAddress string) (types.AuthConfig, error) {
+	authConfig, ok := c.file.AuthConfigs[serverAddress]
+	if !ok {
+		// Maybe they have a legacy config file, we will iterate the keys converting
+		// them to the new format and testing
+		for registry, ac := range c.file.AuthConfigs {
+			if serverAddress == convertToHostname(registry) {
+				return ac, nil
+			}
+		}
+
+		authConfig = types.AuthConfig{}
+	}
+	return authConfig, nil
+}
+
+// Store saves the given credentials in the file store.
+func (c *fileStore) Store(authConfig types.AuthConfig) error {
+	c.file.AuthConfigs[authConfig.ServerAddress] = authConfig
+	return c.file.Save()
+}
+
+func convertToHostname(url string) string {
+	stripped := url
+	if strings.HasPrefix(url, "http://") {
+		stripped = strings.Replace(url, "http://", "", 1)
+	} else if strings.HasPrefix(url, "https://") {
+		stripped = strings.Replace(url, "https://", "", 1)
+	}
+
+	nameParts := strings.SplitN(stripped, "/", 2)
+
+	return nameParts[0]
+}

cliconfig/credentials/file_store_test.go

@@ -0,0 +1,100 @@
+package credentials
+
+import (
+	"io/ioutil"
+	"testing"
+
+	"github.com/docker/docker/cliconfig"
+	"github.com/docker/engine-api/types"
+)
+
+func newConfigFile(auths map[string]types.AuthConfig) *cliconfig.ConfigFile {
+	tmp, _ := ioutil.TempFile("", "docker-test")
+	name := tmp.Name()
+	tmp.Close()
+
+	c := cliconfig.NewConfigFile(name)
+	c.AuthConfigs = auths
+	return c
+}
+
+func TestFileStoreAddCredentials(t *testing.T) {
+	f := newConfigFile(make(map[string]types.AuthConfig))
+
+	s := NewFileStore(f)
+	err := s.Store(types.AuthConfig{
+		Auth:          "super_secret_token",
+		Email:         "foo@example.com",
+		ServerAddress: "https://example.com",
+	})
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(f.AuthConfigs) != 1 {
+		t.Fatalf("expected 1 auth config, got %d", len(f.AuthConfigs))
+	}
+
+	a, ok := f.AuthConfigs["https://example.com"]
+	if !ok {
+		t.Fatalf("expected auth for https://example.com, got %v", f.AuthConfigs)
+	}
+	if a.Auth != "super_secret_token" {
+		t.Fatalf("expected auth `super_secret_token`, got %s", a.Auth)
+	}
+	if a.Email != "foo@example.com" {
+		t.Fatalf("expected email `foo@example.com`, got %s", a.Email)
+	}
+}
+
+func TestFileStoreGet(t *testing.T) {
+	f := newConfigFile(map[string]types.AuthConfig{
+		"https://example.com": {
+			Auth:          "super_secret_token",
+			Email:         "foo@example.com",
+			ServerAddress: "https://example.com",
+		},
+	})
+
+	s := NewFileStore(f)
+	a, err := s.Get("https://example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if a.Auth != "super_secret_token" {
+		t.Fatalf("expected auth `super_secret_token`, got %s", a.Auth)
+	}
+	if a.Email != "foo@example.com" {
+		t.Fatalf("expected email `foo@example.com`, got %s", a.Email)
+	}
+}
+
+func TestFileStoreErase(t *testing.T) {
+	f := newConfigFile(map[string]types.AuthConfig{
+		"https://example.com": {
+			Auth:          "super_secret_token",
+			Email:         "foo@example.com",
+			ServerAddress: "https://example.com",
+		},
+	})
+
+	s := NewFileStore(f)
+	err := s.Erase("https://example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// file store never returns errors, check that the auth config is empty
+	a, err := s.Get("https://example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if a.Auth != "" {
+		t.Fatalf("expected empty auth token, got %s", a.Auth)
+	}
+	if a.Email != "" {
+		t.Fatalf("expected empty email, got %s", a.Email)
+	}
+}

cliconfig/credentials/native_store.go

@@ -0,0 +1,166 @@
+package credentials
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/docker/cliconfig"
+	"github.com/docker/engine-api/types"
+)
+
+const remoteCredentialsPrefix = "docker-credential-"
+
+// Standarize the not found error, so every helper returns
+// the same message and docker can handle it properly.
+var errCredentialsNotFound = errors.New("credentials not found in native keychain")
+
+// command is an interface that remote executed commands implement.
+type command interface {
+	Output() ([]byte, error)
+	Input(in io.Reader)
+}
+
+// credentialsRequest holds information shared between docker and a remote credential store.
+type credentialsRequest struct {
+	ServerURL string
+	Username  string
+	Password  string
+}
+
+// credentialsGetResponse is the information serialized from a remote store
+// when the plugin sends requests to get the user credentials.
+type credentialsGetResponse struct {
+	Username string
+	Password string
+}
+
+// nativeStore implements a credentials store
+// using native keychain to keep credentials secure.
+// It piggybacks into a file store to keep users' emails.
+type nativeStore struct {
+	commandFn func(args ...string) command
+	fileStore Store
+}
+
+// NewNativeStore creates a new native store that
+// uses a remote helper program to manage credentials.
+func NewNativeStore(file *cliconfig.ConfigFile) Store {
+	return &nativeStore{
+		commandFn: shellCommandFn(file.CredentialsStore),
+		fileStore: NewFileStore(file),
+	}
+}
+
+// Erase removes the given credentials from the native store.
+func (c *nativeStore) Erase(serverAddress string) error {
+	if err := c.eraseCredentialsFromStore(serverAddress); err != nil {
+		return err
+	}
+
+	// Fallback to plain text store to remove email
+	return c.fileStore.Erase(serverAddress)
+}
+
+// Get retrieves credentials for a specific server from the native store.
+func (c *nativeStore) Get(serverAddress string) (types.AuthConfig, error) {
+	// load user email if it exist or an empty auth config.
+	auth, _ := c.fileStore.Get(serverAddress)
+
+	creds, err := c.getCredentialsFromStore(serverAddress)
+	if err != nil {
+		return auth, err
+	}
+	auth.Username = creds.Username
+	auth.Password = creds.Password
+
+	return auth, nil
+}
+
+// Store saves the given credentials in the file store.
+func (c *nativeStore) Store(authConfig types.AuthConfig) error {
+	if err := c.storeCredentialsInStore(authConfig); err != nil {
+		return err
+	}
+	authConfig.Username = ""
+	authConfig.Password = ""
+
+	// Fallback to old credential in plain text to save only the email
+	return c.fileStore.Store(authConfig)
+}
+
+// storeCredentialsInStore executes the command to store the credentials in the native store.
+func (c *nativeStore) storeCredentialsInStore(config types.AuthConfig) error {
+	cmd := c.commandFn("store")
+	creds := &credentialsRequest{
+		ServerURL: config.ServerAddress,
+		Username:  config.Username,
+		Password:  config.Password,
+	}
+
+	buffer := new(bytes.Buffer)
+	if err := json.NewEncoder(buffer).Encode(creds); err != nil {
+		return err
+	}
+	cmd.Input(buffer)
+
+	out, err := cmd.Output()
+	if err != nil {
+		t := strings.TrimSpace(string(out))
+		logrus.Debugf("error adding credentials - err: %v, out: `%s`", err, t)
+		return fmt.Errorf(t)
+	}
+
+	return nil
+}
+
+// getCredentialsFromStore executes the command to get the credentials from the native store.
+func (c *nativeStore) getCredentialsFromStore(serverAddress string) (types.AuthConfig, error) {
+	var ret types.AuthConfig
+
+	cmd := c.commandFn("get")
+	cmd.Input(strings.NewReader(serverAddress))
+
+	out, err := cmd.Output()
+	if err != nil {
+		t := strings.TrimSpace(string(out))
+
+		// do not return an error if the credentials are not
+		// in the keyckain. Let docker ask for new credentials.
+		if t == errCredentialsNotFound.Error() {
+			return ret, nil
+		}
+
+		logrus.Debugf("error adding credentials - err: %v, out: `%s`", err, t)
+		return ret, fmt.Errorf(t)
+	}
+
+	var resp credentialsGetResponse
+	if err := json.NewDecoder(bytes.NewReader(out)).Decode(&resp); err != nil {
+		return ret, err
+	}
+
+	ret.Username = resp.Username
+	ret.Password = resp.Password
+	ret.ServerAddress = serverAddress
+	return ret, nil
+}
+
+// eraseCredentialsFromStore executes the command to remove the server redentails from the native store.
+func (c *nativeStore) eraseCredentialsFromStore(serverURL string) error {
+	cmd := c.commandFn("erase")
+	cmd.Input(strings.NewReader(serverURL))
+
+	out, err := cmd.Output()
+	if err != nil {
+		t := strings.TrimSpace(string(out))
+		logrus.Debugf("error adding credentials - err: %v, out: `%s`", err, t)
+		return fmt.Errorf(t)
+	}
+
+	return nil
+}

cliconfig/credentials/native_store_test.go

@@ -0,0 +1,264 @@
+package credentials
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"strings"
+	"testing"
+
+	"github.com/docker/engine-api/types"
+)
+
+const (
+	validServerAddress   = "https://index.docker.io/v1"
+	invalidServerAddress = "https://foobar.example.com"
+	missingCredsAddress  = "https://missing.docker.io/v1"
+)
+
+var errCommandExited = fmt.Errorf("exited 1")
+
+// mockCommand simulates interactions between the docker client and a remote
+// credentials helper.
+// Unit tests inject this mocked command into the remote to control execution.
+type mockCommand struct {
+	arg   string
+	input io.Reader
+}
+
+// Output returns responses from the remote credentials helper.
+// It mocks those reponses based in the input in the mock.
+func (m *mockCommand) Output() ([]byte, error) {
+	in, err := ioutil.ReadAll(m.input)
+	if err != nil {
+		return nil, err
+	}
+	inS := string(in)
+
+	switch m.arg {
+	case "erase":
+		switch inS {
+		case validServerAddress:
+			return nil, nil
+		default:
+			return []byte("error erasing credentials"), errCommandExited
+		}
+	case "get":
+		switch inS {
+		case validServerAddress:
+			return []byte(`{"Username": "foo", "Password": "bar"}`), nil
+		case missingCredsAddress:
+			return []byte(errCredentialsNotFound.Error()), errCommandExited
+		case invalidServerAddress:
+			return []byte("error getting credentials"), errCommandExited
+		}
+	case "store":
+		var c credentialsRequest
+		err := json.NewDecoder(strings.NewReader(inS)).Decode(&c)
+		if err != nil {
+			return []byte("error storing credentials"), errCommandExited
+		}
+		switch c.ServerURL {
+		case validServerAddress:
+			return nil, nil
+		default:
+			return []byte("error storing credentials"), errCommandExited
+		}
+	}
+
+	return []byte("unknown argument"), errCommandExited
+}
+
+// Input sets the input to send to a remote credentials helper.
+func (m *mockCommand) Input(in io.Reader) {
+	m.input = in
+}
+
+func mockCommandFn(args ...string) command {
+	return &mockCommand{
+		arg: args[0],
+	}
+}
+
+func TestNativeStoreAddCredentials(t *testing.T) {
+	f := newConfigFile(make(map[string]types.AuthConfig))
+	f.CredentialsStore = "mock"
+
+	s := &nativeStore{
+		commandFn: mockCommandFn,
+		fileStore: NewFileStore(f),
+	}
+	err := s.Store(types.AuthConfig{
+		Username:      "foo",
+		Password:      "bar",
+		Email:         "foo@example.com",
+		ServerAddress: validServerAddress,
+	})
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(f.AuthConfigs) != 1 {
+		t.Fatalf("expected 1 auth config, got %d", len(f.AuthConfigs))
+	}
+
+	a, ok := f.AuthConfigs[validServerAddress]
+	if !ok {
+		t.Fatalf("expected auth for %s, got %v", validServerAddress, f.AuthConfigs)
+	}
+	if a.Auth != "" {
+		t.Fatalf("expected auth to be empty, got %s", a.Auth)
+	}
+	if a.Username != "" {
+		t.Fatalf("expected username to be empty, got %s", a.Username)
+	}
+	if a.Password != "" {
+		t.Fatalf("expected password to be empty, got %s", a.Password)
+	}
+	if a.Email != "foo@example.com" {
+		t.Fatalf("expected email `foo@example.com`, got %s", a.Email)
+	}
+}
+
+func TestNativeStoreAddInvalidCredentials(t *testing.T) {
+	f := newConfigFile(make(map[string]types.AuthConfig))
+	f.CredentialsStore = "mock"
+
+	s := &nativeStore{
+		commandFn: mockCommandFn,
+		fileStore: NewFileStore(f),
+	}
+	err := s.Store(types.AuthConfig{
+		Username:      "foo",
+		Password:      "bar",
+		Email:         "foo@example.com",
+		ServerAddress: invalidServerAddress,
+	})
+
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+
+	if err.Error() != "error storing credentials" {
+		t.Fatalf("expected `error storing credentials`, got %v", err)
+	}
+
+	if len(f.AuthConfigs) != 0 {
+		t.Fatalf("expected 0 auth config, got %d", len(f.AuthConfigs))
+	}
+}
+
+func TestNativeStoreGet(t *testing.T) {
+	f := newConfigFile(map[string]types.AuthConfig{
+		validServerAddress: {
+			Email: "foo@example.com",
+		},
+	})
+	f.CredentialsStore = "mock"
+
+	s := &nativeStore{
+		commandFn: mockCommandFn,
+		fileStore: NewFileStore(f),
+	}
+	a, err := s.Get(validServerAddress)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if a.Username != "foo" {
+		t.Fatalf("expected username `foo`, got %s", a.Username)
+	}
+	if a.Password != "bar" {
+		t.Fatalf("expected password `bar`, got %s", a.Password)
+	}
+	if a.Email != "foo@example.com" {
+		t.Fatalf("expected email `foo@example.com`, got %s", a.Email)
+	}
+}
+
+func TestNativeStoreGetMissingCredentials(t *testing.T) {
+	f := newConfigFile(map[string]types.AuthConfig{
+		validServerAddress: {
+			Email: "foo@example.com",
+		},
+	})
+	f.CredentialsStore = "mock"
+
+	s := &nativeStore{
+		commandFn: mockCommandFn,
+		fileStore: NewFileStore(f),
+	}
+	_, err := s.Get(missingCredsAddress)
+	if err != nil {
+		// missing credentials do not produce an error
+		t.Fatal(err)
+	}
+}
+
+func TestNativeStoreGetInvalidAddress(t *testing.T) {
+	f := newConfigFile(map[string]types.AuthConfig{
+		validServerAddress: {
+			Email: "foo@example.com",
+		},
+	})
+	f.CredentialsStore = "mock"
+
+	s := &nativeStore{
+		commandFn: mockCommandFn,
+		fileStore: NewFileStore(f),
+	}
+	_, err := s.Get(invalidServerAddress)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+
+	if err.Error() != "error getting credentials" {
+		t.Fatalf("expected `error getting credentials`, got %v", err)
+	}
+}
+
+func TestNativeStoreErase(t *testing.T) {
+	f := newConfigFile(map[string]types.AuthConfig{
+		validServerAddress: {
+			Email: "foo@example.com",
+		},
+	})
+	f.CredentialsStore = "mock"
+
+	s := &nativeStore{
+		commandFn: mockCommandFn,
+		fileStore: NewFileStore(f),
+	}
+	err := s.Erase(validServerAddress)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(f.AuthConfigs) != 0 {
+		t.Fatalf("expected 0 auth configs, got %d", len(f.AuthConfigs))
+	}
+}
+
+func TestNativeStoreEraseInvalidAddress(t *testing.T) {
+	f := newConfigFile(map[string]types.AuthConfig{
+		validServerAddress: {
+			Email: "foo@example.com",
+		},
+	})
+	f.CredentialsStore = "mock"
+
+	s := &nativeStore{
+		commandFn: mockCommandFn,
+		fileStore: NewFileStore(f),
+	}
+	err := s.Erase(invalidServerAddress)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+
+	if err.Error() != "error erasing credentials" {
+		t.Fatalf("expected `error erasing credentials`, got %v", err)
+	}
+}

cliconfig/credentials/shell_command.go

@@ -0,0 +1,28 @@
+package credentials
+
+import (
+	"io"
+	"os/exec"
+)
+
+func shellCommandFn(storeName string) func(args ...string) command {
+	name := remoteCredentialsPrefix + storeName
+	return func(args ...string) command {
+		return &shell{cmd: exec.Command(name, args...)}
+	}
+}
+
+// shell invokes shell commands to talk with a remote credentials helper.
+type shell struct {
+	cmd *exec.Cmd
+}
+
+// Output returns responses from the remote credentials helper.
+func (s *shell) Output() ([]byte, error) {
+	return s.cmd.Output()
+}
+
+// Input sets the input to send to a remote credentials helper.
+func (s *shell) Input(in io.Reader) {
+	s.cmd.Stdin = in
+}

docs/reference/commandline/login.md

@@ -38,3 +38,77 @@ credentials.  When you log in, the command stores encoded credentials in
 
 > **Note**:  When running `sudo docker login` credentials are saved in `/root/.docker/config.json`.
 >
+
+## Credentials store
+
+The Docker Engine can keep user credentials in an external credentials store,
+such as the native keychain of the operating system. Using an external store
+is more secure than storing credentials in the Docker configuration file.
+
+To use a credentials store, you need an external helper program to interact
+with a specific keychain or external store. Docker requires the helper
+program to be in the client's host `$PATH`.
+
+This is the list of currently available credentials helpers and where
+you can download them from:
+
+- Apple OS X keychain: https://github.com/docker/docker-credential-helpers/releases
+- Microsoft Windows Credential Manager: https://github.com/docker/docker-credential-helpers/releases
+
+### Usage
+
+You need to speficy the credentials store in `HOME/.docker/config.json`
+to tell the docker engine to use it:
+
+```json
+{
+	"credsStore": "osxkeychain"
+}
+```
+
+If you are currently logged in, run `docker logout` to remove
+the credentials from the file and run `docker login` again.
+
+### Protocol
+
+Credential helpers can be any program or script that follows a very simple protocol.
+This protocol is heavily inspired by Git, but it differs in the information shared.
+
+The helpers always use the first argument in the command to identify the action.
+There are only three possible values for that argument: `store`, `get`, and `erase`.
+
+The `store` command takes a JSON payload from the standard input. That payload carries
+the server address, to identify the credential, the user name and the password.
+This is an example of that payload:
+
+```json
+{
+	"ServerURL": "https://index.docker.io/v1",
+	"Username": "david",
+	"Password": "passw0rd1"
+}
+```
+
+The `store` command can write error messages to `STDOUT` that the docker engine
+will show if there was an issue.
+
+The `get` command takes a string payload from the standard input. That payload carries
+the server address that the docker engine needs credentials for. This is
+an example of that payload: `https://index.docker.io/v1`.
+
+The `get` command writes a JSON payload to `STDOUT`. Docker reads the user name
+and password from this payload:
+
+```json
+{
+	"Username": "david",
+	"Password": "passw0rd1"
+}
+```
+
+The `erase` command takes a string payload from `STDIN`. That payload carries
+the server address that the docker engine wants to remove credentials for. This is
+an example of that payload: `https://index.docker.io/v1`.
+
+The `erase` command can write error messages to `STDOUT` that the docker engine
+will show if there was an issue.

integration-cli/docker_cli_pull_local_test.go

@@ -361,3 +361,39 @@ func (s *DockerRegistrySuite) TestPullManifestList(c *check.C) {
 
 	dockerCmd(c, "rmi", repoName)
 }
+
+func (s *DockerRegistryAuthSuite) TestPullWithExternalAuth(c *check.C) {
+	osPath := os.Getenv("PATH")
+	defer os.Setenv("PATH", osPath)
+
+	workingDir, err := os.Getwd()
+	c.Assert(err, checker.IsNil)
+	absolute, err := filepath.Abs(filepath.Join(workingDir, "fixtures", "auth"))
+	c.Assert(err, checker.IsNil)
+	testPath := fmt.Sprintf("%s%c%s", osPath, filepath.ListSeparator, absolute)
+
+	os.Setenv("PATH", testPath)
+
+	repoName := fmt.Sprintf("%v/dockercli/busybox:authtest", privateRegistryURL)
+
+	tmp, err := ioutil.TempDir("", "integration-cli-")
+	c.Assert(err, checker.IsNil)
+
+	externalAuthConfig := `{ "credsStore": "shell-test" }`
+
+	configPath := filepath.Join(tmp, "config.json")
+	err = ioutil.WriteFile(configPath, []byte(externalAuthConfig), 0644)
+	c.Assert(err, checker.IsNil)
+
+	dockerCmd(c, "--config", tmp, "login", "-u", s.reg.username, "-p", s.reg.password, "-e", s.reg.email, privateRegistryURL)
+
+	b, err := ioutil.ReadFile(configPath)
+	c.Assert(err, checker.IsNil)
+	c.Assert(string(b), checker.Not(checker.Contains), "\"auth\":")
+	c.Assert(string(b), checker.Contains, "email")
+
+	dockerCmd(c, "--config", tmp, "tag", "busybox", repoName)
+	dockerCmd(c, "--config", tmp, "push", repoName)
+
+	dockerCmd(c, "--config", tmp, "pull", repoName)
+}

integration-cli/fixtures/auth/docker-credential-shell-test

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+set -e
+
+case $1 in
+	"store")
+		in=$(</dev/stdin)
+		server=$(echo "$in" | jq --raw-output ".ServerURL" | sha1sum - | awk '{print $1}')
+
+		username=$(echo "$in" | jq --raw-output ".Username")
+		password=$(echo "$in" | jq --raw-output ".Password")
+		echo "{ \"Username\": \"${username}\", \"Password\": \"${password}\" }" > $TEMP/$server
+		;;
+	"get")
+		in=$(</dev/stdin)
+		server=$(echo "$in" | sha1sum - | awk '{print $1}')
+		if [[ ! -f $TEMP/$server ]]; then
+			echo "credentials not found in native keychain"
+			exit 1
+		fi
+		payload=$(<$TEMP/$server)
+		echo "$payload"
+		;;
+	"erase")
+		in=$(</dev/stdin)
+		server=$(echo "$in" | sha1sum - | awk '{print $1}')
+		rm -f $TEMP/$server
+		;;
+	*)
+		echo "unknown credential option"
+		exit 1
+		;;
+esac