@@ -912,6 +912,17 @@ func postBuild(srv *Server, version float64, w http.ResponseWriter, r *http.Requ

 	rawRm := r.FormValue("rm")

 	repoName, tag := utils.ParseRepositoryTag(repoName)

+	authEncoded := r.Header.Get("X-Registry-Auth")

+	authConfig := &auth.AuthConfig{}

+	if authEncoded != "" {

+		authJson := base64.NewDecoder(base64.URLEncoding, strings.NewReader(authEncoded))

+		if err := json.NewDecoder(authJson).Decode(authConfig); err != nil {

+			// for a pull it is not an error if no auth was given

+			// to increase compatibility with the existing api it is defaulting to be empty

+			authConfig = &auth.AuthConfig{}

+		}

+	}

+

 	var context io.Reader

 	if remoteURL == "" {

@@ -978,7 +989,7 @@ func postBuild(srv *Server, version float64, w http.ResponseWriter, r *http.Requ

 			Writer:          utils.NewWriteFlusher(w),

 			StreamFormatter: sf,

 		},

-		!suppressOutput, !noCache, rm, utils.NewWriteFlusher(w), sf)

+		!suppressOutput, !noCache, rm, utils.NewWriteFlusher(w), sf, authConfig)

 	id, err := b.Build(context)

 	if err != nil {

 		if sf.Used() {

@@ -4,6 +4,7 @@ import (

 	"encoding/json"

 	"fmt"

 	"github.com/dotcloud/docker/archive"

+	"github.com/dotcloud/docker/auth"

 	"github.com/dotcloud/docker/utils"

 	"io"

 	"io/ioutil"

@@ -33,6 +34,8 @@ type buildFile struct {

 	utilizeCache bool

 	rm           bool

+	authConfig *auth.AuthConfig

+

 	tmpContainers map[string]struct{}

 	tmpImages     map[string]struct{}

@@ -57,7 +60,7 @@ func (b *buildFile) CmdFrom(name string) error {

 	if err != nil {

 		if b.runtime.graph.IsNotExist(err) {

 			remote, tag := utils.ParseRepositoryTag(name)

-			if err := b.srv.ImagePull(remote, tag, b.outOld, b.sf, nil, nil, true); err != nil {

+			if err := b.srv.ImagePull(remote, tag, b.outOld, b.sf, b.authConfig, nil, true); err != nil {

 				return err

 			}

 			image, err = b.runtime.repositories.LookupImage(name)

@@ -568,7 +571,7 @@ func (b *buildFile) Build(context io.Reader) (string, error) {

 	return "", fmt.Errorf("An error occurred during the build\n")

 }

-func NewBuildFile(srv *Server, outStream, errStream io.Writer, verbose, utilizeCache, rm bool, outOld io.Writer, sf *utils.StreamFormatter) BuildFile {

+func NewBuildFile(srv *Server, outStream, errStream io.Writer, verbose, utilizeCache, rm bool, outOld io.Writer, sf *utils.StreamFormatter, auth *auth.AuthConfig) BuildFile {

 	return &buildFile{

 		runtime:       srv.runtime,

 		srv:           srv,

@@ -581,6 +584,7 @@ func NewBuildFile(srv *Server, outStream, errStream io.Writer, verbose, utilizeC

 		utilizeCache:  utilizeCache,

 		rm:            rm,

 		sf:            sf,

+		authConfig:    auth,

 		outOld:        outOld,

 	}

 }

@@ -226,6 +226,12 @@ func (cli *DockerCli) CmdBuild(args ...string) error {

 	}

 	headers := http.Header(make(map[string][]string))

+	buf, err := json.Marshal(cli.configFile)

+	if err != nil {

+		return err

+	}

+	headers.Add("X-Registry-Auth", base64.URLEncoding.EncodeToString(buf))

+

 	if context != nil {

 		headers.Set("Content-Type", "application/tar")

 	}

@@ -1026,6 +1026,7 @@ Build an image from Dockerfile via stdin

    :query q: suppress verbose build output

    :query nocache: do not use the cache when building the image

    :reqheader Content-type: should be set to ``"application/tar"``.

+   :reqheader X-Registry-Auth: base64-encoded AuthConfig object

    :statuscode 200: no error

    :statuscode 500: server error