2 files changed, 21 insertions, 19 deletions

diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 780bf5279..b540bbeb8 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -236,9 +236,6 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 	}
 
 	if c.config.User != "" {
-		if !c.state.Mounted {
-			return nil, errors.Wrapf(ErrCtrStateInvalid, "container %s must be mounted in order to translate User field", c.ID())
-		}
 		// User and Group must go together
 		g.SetProcessUID(uint32(execUser.Uid))
 		g.SetProcessGID(uint32(execUser.Gid))
@@ -246,9 +243,6 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 
 	// Add addition groups if c.config.GroupAdd is not empty
 	if len(c.config.Groups) > 0 {
-		if !c.state.Mounted {
-			return nil, errors.Wrapf(ErrCtrStateInvalid, "container %s must be mounted in order to add additional groups", c.ID())
-		}
 		gids, _ := lookup.GetContainerGroups(c.config.Groups, c.state.Mountpoint, nil)
 		for _, gid := range gids {
 			g.AddProcessAdditionalGid(gid)
@@ -800,7 +794,6 @@ func (c *Container) generateHosts() (string, error) {
 func (c *Container) generatePasswd() (string, error) {
 	var (
 		groupspec string
-		group     *user.Group
 		gid       int
 	)
 	if c.config.User == "" {
@@ -825,17 +818,16 @@ func (c *Container) generatePasswd() (string, error) {
 		return "", nil
 	}
 	if groupspec != "" {
-		if !c.state.Mounted {
-			return "", errors.Wrapf(ErrCtrStateInvalid, "container %s must be mounted in order to translate group field for passwd record", c.ID())
-		}
-		group, err = lookup.GetGroup(c.state.Mountpoint, groupspec)
-		if err != nil {
-			if err == user.ErrNoGroupEntries {
+		ugid, err := strconv.ParseUint(groupspec, 10, 32)
+		if err == nil {
+			gid = int(ugid)
+		} else {
+			group, err := lookup.GetGroup(c.state.Mountpoint, groupspec)
+			if err != nil {
 				return "", errors.Wrapf(err, "unable to get gid %s from group file", groupspec)
 			}
-			return "", err
+			gid = group.Gid
 		}
-		gid = group.Gid
 	}
 	originPasswdFile := filepath.Join(c.state.Mountpoint, "/etc/passwd")
 	orig, err := ioutil.ReadFile(originPasswdFile)
diff --git a/pkg/lookup/lookup.go b/pkg/lookup/lookup.go
index a9d975b4b..70b97144f 100644
--- a/pkg/lookup/lookup.go
+++ b/pkg/lookup/lookup.go
@@ -99,9 +99,11 @@ func GetContainerGroups(groups []string, containerMount string, override *Overri
 	return uintgids, nil
 }
 
-// GetUser takes a containermount path and user name or id and returns
+// GetUser takes a containermount path and user name or ID and returns
 // a matching User structure from /etc/passwd.  If it cannot locate a user
 // with the provided information, an ErrNoPasswdEntries is returned.
+// When the provided user name was an ID, a User structure with Uid
+// set is returned along with ErrNoPasswdEntries.
 func GetUser(containerMount, userIDorName string) (*user.User, error) {
 	var inputIsName bool
 	uid, err := strconv.Atoi(userIDorName)
@@ -124,12 +126,17 @@ func GetUser(containerMount, userIDorName string) (*user.User, error) {
 	if len(users) > 0 {
 		return &users[0], nil
 	}
+	if !inputIsName {
+		return &user.User{Uid: uid}, user.ErrNoPasswdEntries
+	}
 	return nil, user.ErrNoPasswdEntries
 }
 
-// GetGroup takes ac ontainermount path and a group name or id and returns
-// a match Group struct from /etc/group.  if it cannot locate a group,
-// an ErrNoGroupEntries error is returned.
+// GetGroup takes a containermount path and a group name or ID and returns
+// a match Group struct from /etc/group.  If it cannot locate a group,
+// an ErrNoGroupEntries error is returned.  When the provided group name
+// was an ID, a Group structure with Gid set is returned along with
+// ErrNoGroupEntries.
 func GetGroup(containerMount, groupIDorName string) (*user.Group, error) {
 	var inputIsName bool
 	gid, err := strconv.Atoi(groupIDorName)
@@ -154,5 +161,8 @@ func GetGroup(containerMount, groupIDorName string) (*user.Group, error) {
 	if len(groups) > 0 {
 		return &groups[0], nil
 	}
+	if !inputIsName {
+		return &user.Group{Gid: gid}, user.ErrNoGroupEntries
+	}
 	return nil, user.ErrNoGroupEntries
 }