fix(WORKDIR): use the config.User for the new dir permissions (#2269)

WORKDIR ignores the currently set USER and creates the new directories
with the root user ownership.

This changes that, by executing a chown after the mkdir if needed, and
also handle the case where the provided USER is an uid and the passwd
file is not available to resolve to the username.

Fixes #2259

Signed-off-by: Aris Buzachis <buzachis.aris@gmail.com>

Signed-off-by: Aris Buzachis <buzachis.aris@gmail.com>

integration/dockerfiles/Dockerfile_test_workdir_with_user

@@ -0,0 +1,41 @@
+FROM debian:9.11
+RUN groupadd -g 10000 bar
+RUN useradd -c "Foo user" -u 10000 -g 10000 -m foo
+
+
+# no passwd file
+FROM scratch
+
+# without a USER Set
+WORKDIR /workdir/wo/user
+
+USER 9999
+WORKDIR /workdir/w/uid
+
+USER 9999:9999
+WORKDIR /workdir/w/uid_gid
+
+USER 0
+WORKDIR /workdir/w/root_uid
+
+USER root
+WORKDIR /workdir/w/root_username
+
+# with passwd file
+COPY --from=0 /etc/passwd /etc/passwd
+COPY --from=0 /etc/group /etc/group
+
+USER foo
+WORKDIR /workdir/w/foo_username
+
+USER foo:10000
+WORKDIR /workdir/w/foo_username_gid
+
+USER 10000
+WORKDIR /workdir/w/foo_uid
+
+USER 10000:10000
+WORKDIR /workdir/w/foo_uid_gid
+
+USER 10000:bar
+WORKDIR /workdir/w/foo_uid_groupname

pkg/commands/workdir.go

@@ -21,6 +21,7 @@ import (
 	"path/filepath"
 
 	"github.com/GoogleContainerTools/kaniko/pkg/dockerfile"
+	"github.com/pkg/errors"
 
 	"github.com/GoogleContainerTools/kaniko/pkg/util"
 	v1 "github.com/google/go-containerregistry/pkg/v1"
@@ -35,7 +36,7 @@ type WorkdirCommand struct {
 }
 
 // For testing
-var mkdir = os.MkdirAll
+var mkdirAllWithPermissions = util.MkdirAllWithPermissions
 
 func (w *WorkdirCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.BuildArgs) error {
 	logrus.Info("Cmd: workdir")
@@ -59,9 +60,21 @@ func (w *WorkdirCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile
 	// Only create and snapshot the dir if it didn't exist already
 	w.snapshotFiles = []string{}
 	if _, err := os.Stat(config.WorkingDir); os.IsNotExist(err) {
-		logrus.Infof("Creating directory %s", config.WorkingDir)
+		uid, gid := int64(-1), int64(-1)
+
+		if config.User != "" {
+			logrus.Debugf("Fetching uid and gid for USER '%s'", config.User)
+			uid, gid, err = util.GetUserGroup(config.User, replacementEnvs)
+			if err != nil {
+				return errors.Wrapf(err, "identifying uid and gid for user %s", config.User)
+			}
+		}
+
+		logrus.Infof("Creating directory %s with uid %d and gid %d", config.WorkingDir, uid, gid)
 		w.snapshotFiles = append(w.snapshotFiles, config.WorkingDir)
-		return mkdir(config.WorkingDir, 0755)
+		if err := mkdirAllWithPermissions(config.WorkingDir, 0755, uid, gid); err != nil {
+			return errors.Wrapf(err, "creating workdir %s", config.WorkingDir)
+		}
 	}
 	return nil
 }

pkg/commands/workdir_test.go

@@ -83,17 +83,17 @@ var workdirTests = []struct {
 }
 
 // For testing
-func mockDir(p string, fi os.FileMode) error {
+func mockDir(path string, mode os.FileMode, uid, gid int64) error {
 	return nil
 }
 func TestWorkdirCommand(t *testing.T) {
 
 	// Mock out mkdir for testing.
-	oldMkdir := mkdir
-	mkdir = mockDir
+	oldMkdir := mkdirAllWithPermissions
+	mkdirAllWithPermissions = mockDir
 
 	defer func() {
-		mkdir = oldMkdir
+		mkdirAllWithPermissions = oldMkdir
 	}()
 
 	cfg := &v1.Config{

pkg/util/command_util.go

@@ -442,8 +442,8 @@ func LookupUser(userStr string) (*user.User, error) {
 	userObj, err := user.Lookup(userStr)
 	if err != nil {
 		unknownUserErr := new(user.UnknownUserError)
-		// only return if it's not an unknown user error
-		if !errors.As(err, unknownUserErr) {
+		// only return if it's not an unknown user error or the passwd file does not exist
+		if !errors.As(err, unknownUserErr) && !os.IsNotExist(err) {
 			return nil, err
 		}
 

pkg/util/fs_util.go

@@ -348,7 +348,7 @@ func ExtractFile(dest string, hdr *tar.Header, tr io.Reader) error {
 		currFile.Close()
 	case tar.TypeDir:
 		logrus.Tracef("Creating dir %s", path)
-		if err := mkdirAllWithPermissions(path, mode, int64(uid), int64(gid)); err != nil {
+		if err := MkdirAllWithPermissions(path, mode, int64(uid), int64(gid)); err != nil {
 			return err
 		}
 
@@ -663,7 +663,7 @@ func CopyDir(src, dest string, context FileContext, uid, gid int64) ([]string, e
 
 			mode := fi.Mode()
 			uid, gid := DetermineTargetFileOwnership(fi, uid, gid)
-			if err := mkdirAllWithPermissions(destPath, mode, uid, gid); err != nil {
+			if err := MkdirAllWithPermissions(destPath, mode, uid, gid); err != nil {
 				return nil, err
 			}
 		} else if IsSymlink(fi) {
@@ -806,7 +806,7 @@ func Volumes() []string {
 	return volumes
 }
 
-func mkdirAllWithPermissions(path string, mode os.FileMode, uid, gid int64) error {
+func MkdirAllWithPermissions(path string, mode os.FileMode, uid, gid int64) error {
 	// Check if a file already exists on the path, if yes then delete it
 	info, err := os.Stat(path)
 	if err == nil && !info.IsDir() {