@@ -109,7 +109,6 @@ func (d *Daemon) getActiveContainer(name string) (*Container, error) {

 }

 func (d *Daemon) ContainerExecCreate(config *runconfig.ExecConfig) (string, error) {

-

 	// Not all drivers support Exec (LXC for example)

 	if err := checkExecSupport(d.execDriver.Name()); err != nil {

 		return "", err

@@ -123,11 +122,16 @@ func (d *Daemon) ContainerExecCreate(config *runconfig.ExecConfig) (string, erro

 	cmd := runconfig.NewCommand(config.Cmd...)

 	entrypoint, args := d.getEntrypointAndArgs(runconfig.NewEntrypoint(), cmd)

+	user := config.User

+	if len(user) == 0 {

+		user = container.Config.User

+	}

+

 	processConfig := execdriver.ProcessConfig{

 		Tty:        config.Tty,

 		Entrypoint: entrypoint,

 		Arguments:  args,

-		User:       config.User,

+		User:       user,

 	}

 	execConfig := &execConfig{

@@ -445,7 +445,6 @@ func (s *DockerSuite) TestInspectExecID(c *check.C) {

 }

 func (s *DockerSuite) TestLinksPingLinkedContainersOnRename(c *check.C) {

-

 	var out string

 	out, _ = dockerCmd(c, "run", "-d", "--name", "container1", "busybox", "top")

 	idA := strings.TrimSpace(out)

@@ -610,7 +609,6 @@ func (s *DockerSuite) TestRunMutableNetworkFiles(c *check.C) {

 }

 func (s *DockerSuite) TestExecWithUser(c *check.C) {

-

 	runCmd := exec.Command(dockerBinary, "run", "-d", "--name", "parent", "busybox", "top")

 	if out, _, err := runCommandWithOutput(runCmd); err != nil {

 		c.Fatal(out, err)

@@ -635,3 +633,22 @@ func (s *DockerSuite) TestExecWithUser(c *check.C) {

 	}

 }

+

+func (s *DockerSuite) TestExecWithImageUser(c *check.C) {

+	name := "testbuilduser"

+	_, err := buildImage(name,

+		`FROM busybox

+		RUN echo 'dockerio:x:1001:1001::/bin:/bin/false' >> /etc/passwd

+		USER dockerio`,

+		true)

+	if err != nil {

+		c.Fatalf("Could not build image %s: %v", name, err)

+	}

+

+	dockerCmd(c, "run", "-d", "--name", "dockerioexec", name, "top")

+

+	out, _ := dockerCmd(c, "exec", "dockerioexec", "whoami")

+	if !strings.Contains(out, "dockerio") {

+		c.Fatalf("exec with user by id expected dockerio user got %s", out)

+	}

+}