@@ -56,6 +56,7 @@ type copyInstruction struct {

 	cmdName                 string

 	infos                   []copyInfo

 	dest                    string

+	chownStr                string

 	allowLocalDecompression bool

 }

@@ -369,6 +370,7 @@ func downloadSource(output io.Writer, stdout io.Writer, srcURL string) (remote b

 type copyFileOptions struct {

 	decompress bool

 	archiver   *archive.Archiver

+	chownPair  idtools.IDPair

 }

 func performCopyForInfo(dest copyInfo, source copyInfo, options copyFileOptions) error {

@@ -388,7 +390,7 @@ func performCopyForInfo(dest copyInfo, source copyInfo, options copyFileOptions)

 		return errors.Wrapf(err, "source path not found")

 	}

 	if src.IsDir() {

-		return copyDirectory(archiver, srcPath, destPath)

+		return copyDirectory(archiver, srcPath, destPath, options.chownPair)

 	}

 	if options.decompress && archive.IsArchivePath(srcPath) && !source.noDecompress {

 		return archiver.UntarPath(srcPath, destPath)

@@ -405,26 +407,28 @@ func performCopyForInfo(dest copyInfo, source copyInfo, options copyFileOptions)

 		// is a symlink

 		destPath = filepath.Join(destPath, filepath.Base(source.path))

 	}

-	return copyFile(archiver, srcPath, destPath)

+	return copyFile(archiver, srcPath, destPath, options.chownPair)

 }

-func copyDirectory(archiver *archive.Archiver, source, dest string) error {

+func copyDirectory(archiver *archive.Archiver, source, dest string, chownPair idtools.IDPair) error {

+	destExists, err := isExistingDirectory(dest)

+	if err != nil {

+		return errors.Wrapf(err, "failed to query destination path")

+	}

 	if err := archiver.CopyWithTar(source, dest); err != nil {

 		return errors.Wrapf(err, "failed to copy directory")

 	}

-	return fixPermissions(source, dest, archiver.IDMappings.RootPair())

+	return fixPermissions(source, dest, chownPair, !destExists)

 }

-func copyFile(archiver *archive.Archiver, source, dest string) error {

-	rootIDs := archiver.IDMappings.RootPair()

-

-	if err := idtools.MkdirAllAndChownNew(filepath.Dir(dest), 0755, rootIDs); err != nil {

+func copyFile(archiver *archive.Archiver, source, dest string, chownPair idtools.IDPair) error {

+	if err := idtools.MkdirAllAndChownNew(filepath.Dir(dest), 0755, chownPair); err != nil {

 		return errors.Wrapf(err, "failed to create new directory")

 	}

 	if err := archiver.CopyFileWithTar(source, dest); err != nil {

 		return errors.Wrapf(err, "failed to copy file")

 	}

-	return fixPermissions(source, dest, rootIDs)

+	return fixPermissions(source, dest, chownPair, false)

 }

 func endsInSlash(path string) bool {

@@ -9,10 +9,16 @@ import (

 	"github.com/docker/docker/pkg/idtools"

 )

-func fixPermissions(source, destination string, rootIDs idtools.IDPair) error {

-	skipChownRoot, err := isExistingDirectory(destination)

-	if err != nil {

-		return err

+func fixPermissions(source, destination string, rootIDs idtools.IDPair, overrideSkip bool) error {

+	var (

+		skipChownRoot bool

+		err           error

+	)

+	if !overrideSkip {

+		skipChownRoot, err = isExistingDirectory(destination)

+		if err != nil {

+			return err

+		}

 	}

 	// We Walk on the source rather than on the destination because we don't

@@ -2,7 +2,7 @@ package dockerfile

 import "github.com/docker/docker/pkg/idtools"

-func fixPermissions(source, destination string, rootIDs idtools.IDPair) error {

+func fixPermissions(source, destination string, rootIDs idtools.IDPair, overrideSkip bool) error {

 	// chown is not supported on Windows

 	return nil

 }

@@ -146,6 +146,7 @@ func add(req dispatchRequest) error {

 		return errAtLeastTwoArguments("ADD")

 	}

+	flChown := req.flags.AddString("chown", "")

 	if err := req.flags.Parse(); err != nil {

 		return err

 	}

@@ -157,6 +158,7 @@ func add(req dispatchRequest) error {

 	if err != nil {

 		return err

 	}

+	copyInstruction.chownStr = flChown.Value

 	copyInstruction.allowLocalDecompression = true

 	return req.builder.performCopy(req.state, copyInstruction)

@@ -172,6 +174,7 @@ func dispatchCopy(req dispatchRequest) error {

 	}

 	flFrom := req.flags.AddString("from", "")

+	flChown := req.flags.AddString("chown", "")

 	if err := req.flags.Parse(); err != nil {

 		return err

 	}

@@ -187,6 +190,7 @@ func dispatchCopy(req dispatchRequest) error {

 	if err != nil {

 		return err

 	}

+	copyInstruction.chownStr = flChown.Value

 	return req.builder.performCopy(req.state, copyInstruction)

 }

@@ -7,13 +7,18 @@ import (

 	"crypto/sha256"

 	"encoding/hex"

 	"fmt"

+	"path/filepath"

+	"strconv"

 	"strings"

 	"github.com/docker/docker/api/types"

 	"github.com/docker/docker/api/types/backend"

 	"github.com/docker/docker/api/types/container"

 	"github.com/docker/docker/image"

+	"github.com/docker/docker/pkg/idtools"

 	"github.com/docker/docker/pkg/stringid"

+	"github.com/docker/docker/pkg/symlink"

+	lcUser "github.com/opencontainers/runc/libcontainer/user"

 	"github.com/pkg/errors"

 )

@@ -107,10 +112,16 @@ func (b *Builder) exportImage(state *dispatchState, imageMount *imageMount, runC

 func (b *Builder) performCopy(state *dispatchState, inst copyInstruction) error {

 	srcHash := getSourceHashFromInfos(inst.infos)

+	var chownComment string

+	if inst.chownStr != "" {

+		chownComment = fmt.Sprintf("--chown=%s", inst.chownStr)

+	}

+	commentStr := fmt.Sprintf("%s %s%s in %s ", inst.cmdName, chownComment, srcHash, inst.dest)

+

 	// TODO: should this have been using origPaths instead of srcHash in the comment?

 	runConfigWithCommentCmd := copyRunConfig(

 		state.runConfig,

-		withCmdCommentString(fmt.Sprintf("%s %s in %s ", inst.cmdName, srcHash, inst.dest), b.platform))

+		withCmdCommentString(commentStr, b.platform))

 	hit, err := b.probeCache(state, runConfigWithCommentCmd)

 	if err != nil || hit {

 		return err

@@ -125,9 +136,21 @@ func (b *Builder) performCopy(state *dispatchState, inst copyInstruction) error

 		return err

 	}

+	chownPair := b.archiver.IDMappings.RootPair()

+	// if a chown was requested, perform the steps to get the uid, gid

+	// translated (if necessary because of user namespaces), and replace

+	// the root pair with the chown pair for copy operations

+	if inst.chownStr != "" {

+		chownPair, err = parseChownFlag(inst.chownStr, destInfo.root, b.archiver.IDMappings)

+		if err != nil {

+			return errors.Wrapf(err, "unable to convert uid/gid chown string to host mapping")

+		}

+	}

+

 	opts := copyFileOptions{

 		decompress: inst.allowLocalDecompression,

 		archiver:   b.archiver,

+		chownPair:  chownPair,

 	}

 	for _, info := range inst.infos {

 		if err := performCopyForInfo(destInfo, info, opts); err != nil {

@@ -137,6 +160,88 @@ func (b *Builder) performCopy(state *dispatchState, inst copyInstruction) error

 	return b.exportImage(state, imageMount, runConfigWithCommentCmd)

 }

+func parseChownFlag(chown, ctrRootPath string, idMappings *idtools.IDMappings) (idtools.IDPair, error) {

+	var userStr, grpStr string

+	parts := strings.Split(chown, ":")

+	if len(parts) > 2 {

+		return idtools.IDPair{}, errors.New("invalid chown string format: " + chown)

+	}

+	if len(parts) == 1 {

+		// if no group specified, use the user spec as group as well

+		userStr, grpStr = parts[0], parts[0]

+	} else {

+		userStr, grpStr = parts[0], parts[1]

+	}

+

+	passwdPath, err := symlink.FollowSymlinkInScope(filepath.Join(ctrRootPath, "etc", "passwd"), ctrRootPath)

+	if err != nil {

+		return idtools.IDPair{}, errors.Wrapf(err, "can't resolve /etc/passwd path in container rootfs")

+	}

+	groupPath, err := symlink.FollowSymlinkInScope(filepath.Join(ctrRootPath, "etc", "group"), ctrRootPath)

+	if err != nil {

+		return idtools.IDPair{}, errors.Wrapf(err, "can't resolve /etc/group path in container rootfs")

+	}

+	uid, err := lookupUser(userStr, passwdPath)

+	if err != nil {

+		return idtools.IDPair{}, errors.Wrapf(err, "can't find uid for user "+userStr)

+	}

+	gid, err := lookupGroup(grpStr, groupPath)

+	if err != nil {

+		return idtools.IDPair{}, errors.Wrapf(err, "can't find gid for group "+grpStr)

+	}

+

+	// convert as necessary because of user namespaces

+	chownPair, err := idMappings.ToHost(idtools.IDPair{UID: uid, GID: gid})

+	if err != nil {

+		return idtools.IDPair{}, errors.Wrapf(err, "unable to convert uid/gid to host mapping")

+	}

+	return chownPair, nil

+}

+

+func lookupUser(userStr, filepath string) (int, error) {

+	// if the string is actually a uid integer, parse to int and return

+	// as we don't need to translate with the help of files

+	uid, err := strconv.Atoi(userStr)

+	if err == nil {

+		return uid, nil

+	}

+	users, err := lcUser.ParsePasswdFileFilter(filepath, func(u lcUser.User) bool {

+		if u.Name == userStr {

+			return true

+		}

+		return false

+	})

+	if err != nil {

+		return 0, err

+	}

+	if len(users) == 0 {

+		return 0, errors.New("no such user: " + userStr)

+	}

+	return users[0].Uid, nil

+}

+

+func lookupGroup(groupStr, filepath string) (int, error) {

+	// if the string is actually a gid integer, parse to int and return

+	// as we don't need to translate with the help of files

+	gid, err := strconv.Atoi(groupStr)

+	if err == nil {

+		return gid, nil

+	}

+	groups, err := lcUser.ParseGroupFileFilter(filepath, func(g lcUser.Group) bool {

+		if g.Name == groupStr {

+			return true

+		}

+		return false

+	})

+	if err != nil {

+		return 0, err

+	}

+	if len(groups) == 0 {

+		return 0, errors.New("no such group: " + groupStr)

+	}

+	return groups[0].Gid, nil

+}

+

 func createDestInfo(workingDir string, inst copyInstruction, imageMount *imageMount) (copyInfo, error) {

 	// Twiddle the destination when it's a relative path - meaning, make it

 	// relative to the WORKINGDIR

@@ -2,6 +2,8 @@ package dockerfile

 import (

 	"fmt"

+	"os"

+	"path/filepath"

 	"runtime"

 	"testing"

@@ -11,6 +13,7 @@ import (

 	"github.com/docker/docker/builder"

 	"github.com/docker/docker/builder/remotecontext"

 	"github.com/docker/docker/pkg/archive"

+	"github.com/docker/docker/pkg/idtools"

 	"github.com/stretchr/testify/assert"

 	"github.com/stretchr/testify/require"

 )

@@ -129,3 +132,130 @@ func TestCopyRunConfig(t *testing.T) {

 	}

 }

+

+func TestChownFlagParsing(t *testing.T) {

+	testFiles := map[string]string{

+		"passwd": `root:x:0:0::/bin:/bin/false

+bin:x:1:1::/bin:/bin/false

+wwwwww:x:21:33::/bin:/bin/false

+unicorn:x:1001:1002::/bin:/bin/false

+		`,

+		"group": `root:x:0:

+bin:x:1:

+wwwwww:x:33:

+unicorn:x:1002:

+somegrp:x:5555:

+othergrp:x:6666:

+		`,

+	}

+	// test mappings for validating use of maps

+	idMaps := []idtools.IDMap{

+		{

+			ContainerID: 0,

+			HostID:      100000,

+			Size:        65536,

+		},

+	}

+	remapped := idtools.NewIDMappingsFromMaps(idMaps, idMaps)

+	unmapped := &idtools.IDMappings{}

+

+	contextDir, cleanup := createTestTempDir(t, "", "builder-chown-parse-test")

+	defer cleanup()

+

+	if err := os.Mkdir(filepath.Join(contextDir, "etc"), 0755); err != nil {

+		t.Fatalf("error creating test directory: %v", err)

+	}

+

+	for filename, content := range testFiles {

+		createTestTempFile(t, filepath.Join(contextDir, "etc"), filename, content, 0644)

+	}

+

+	// positive tests

+	for _, testcase := range []struct {

+		name      string

+		chownStr  string

+		idMapping *idtools.IDMappings

+		expected  idtools.IDPair

+	}{

+		{

+			name:      "UIDNoMap",

+			chownStr:  "1",

+			idMapping: unmapped,

+			expected:  idtools.IDPair{UID: 1, GID: 1},

+		},

+		{

+			name:      "UIDGIDNoMap",

+			chownStr:  "0:1",

+			idMapping: unmapped,

+			expected:  idtools.IDPair{UID: 0, GID: 1},

+		},

+		{

+			name:      "UIDWithMap",

+			chownStr:  "0",

+			idMapping: remapped,

+			expected:  idtools.IDPair{UID: 100000, GID: 100000},

+		},

+		{

+			name:      "UIDGIDWithMap",

+			chownStr:  "1:33",

+			idMapping: remapped,

+			expected:  idtools.IDPair{UID: 100001, GID: 100033},

+		},

+		{

+			name:      "UserNoMap",

+			chownStr:  "bin:5555",

+			idMapping: unmapped,

+			expected:  idtools.IDPair{UID: 1, GID: 5555},

+		},

+		{

+			name:      "GroupWithMap",

+			chownStr:  "0:unicorn",

+			idMapping: remapped,

+			expected:  idtools.IDPair{UID: 100000, GID: 101002},

+		},

+		{

+			name:      "UserOnlyWithMap",

+			chownStr:  "unicorn",

+			idMapping: remapped,

+			expected:  idtools.IDPair{UID: 101001, GID: 101002},

+		},

+	} {

+		t.Run(testcase.name, func(t *testing.T) {

+			idPair, err := parseChownFlag(testcase.chownStr, contextDir, testcase.idMapping)

+			require.NoError(t, err, "Failed to parse chown flag: %q", testcase.chownStr)

+			assert.Equal(t, testcase.expected, idPair, "chown flag mapping failure")

+		})

+	}

+

+	// error tests

+	for _, testcase := range []struct {

+		name      string

+		chownStr  string

+		idMapping *idtools.IDMappings

+		descr     string

+	}{

+		{

+			name:      "BadChownFlagFormat",

+			chownStr:  "bob:1:555",

+			idMapping: unmapped,

+			descr:     "invalid chown string format: bob:1:555",

+		},

+		{

+			name:      "UserNoExist",

+			chownStr:  "bob",

+			idMapping: unmapped,

+			descr:     "can't find uid for user bob: no such user: bob",

+		},

+		{

+			name:      "GroupNoExist",

+			chownStr:  "root:bob",

+			idMapping: unmapped,

+			descr:     "can't find gid for group bob: no such group: bob",

+		},

+	} {

+		t.Run(testcase.name, func(t *testing.T) {

+			_, err := parseChownFlag(testcase.chownStr, contextDir, testcase.idMapping)

+			assert.EqualError(t, err, testcase.descr, "Expected error string doesn't match")

+		})

+	}

+}

@@ -409,6 +409,35 @@ func (s *DockerSuite) TestBuildAddRemoteNoDecompress(c *check.C) {

 	assert.Contains(c, string(out), "Successfully built")

 }

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

+	testRequires(c, DaemonIsLinux)

+	dockerfile := `FROM busybox

+		RUN echo 'test1:x:1001:1001::/bin:/bin/false' >> /etc/passwd

+		RUN echo 'test1:x:1001:' >> /etc/group

+		RUN echo 'test2:x:1002:' >> /etc/group

+		COPY --chown=test1:1002 . /new_dir

+		RUN ls -l /

+		RUN [ $(ls -l / | grep new_dir | awk '{print $3":"$4}') = 'test1:test2' ]

+		RUN [ $(ls -nl / | grep new_dir | awk '{print $3":"$4}') = '1001:1002' ]

+	`

+	ctx := fakecontext.New(c, "",

+		fakecontext.WithDockerfile(dockerfile),

+		fakecontext.WithFile("test_file1", "some test content"),

+	)

+	defer ctx.Close()

+

+	res, body, err := request.Post(

+		"/build",

+		request.RawContent(ctx.AsTarReader(c)),

+		request.ContentType("application/x-tar"))

+	c.Assert(err, checker.IsNil)

+	c.Assert(res.StatusCode, checker.Equals, http.StatusOK)

+

+	out, err := testutil.ReadBody(body)

+	require.NoError(c, err)

+	assert.Contains(c, string(out), "Successfully built")

+}

+

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

 	testRequires(c, ExperimentalDaemon)