podman: implement userns=keep-id

add missing implementation for userns=keep-id and enable the user
namespaces tests.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

2 files changed, 32 insertions, 2 deletions

diff --git a/pkg/specgen/generate/namespaces.go b/pkg/specgen/generate/namespaces.go
index 2aaeb9513..1fdc921ce 100644
--- a/pkg/specgen/generate/namespaces.go
+++ b/pkg/specgen/generate/namespaces.go
@@ -10,6 +10,7 @@ import (
 	"github.com/containers/libpod/pkg/cgroups"
 	"github.com/containers/libpod/pkg/rootless"
 	"github.com/containers/libpod/pkg/specgen"
+	"github.com/containers/libpod/pkg/util"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/opencontainers/runtime-tools/generate"
 	"github.com/pkg/errors"
@@ -175,6 +176,13 @@ func GenerateNamespaceOptions(s *specgen.SpecGenerator, rt *libpod.Runtime, pod
 
 	// User
 	switch s.UserNS.NSMode {
+	case specgen.KeepID:
+		if rootless.IsRootless() {
+			s.User = ""
+		} else {
+			// keep-id as root doesn't need a user namespace
+			s.UserNS.NSMode = specgen.Host
+		}
 	case specgen.FromPod:
 		if pod == nil || infraCtr == nil {
 			return nil, errNoInfra
@@ -378,6 +386,18 @@ func specConfigureNamespaces(s *specgen.SpecGenerator, g *generate.Generator, rt
 		if err := g.RemoveLinuxNamespace(string(spec.UserNamespace)); err != nil {
 			return err
 		}
+	case specgen.KeepID:
+		var (
+			err      error
+			uid, gid int
+		)
+		s.IDMappings, uid, gid, err = util.GetKeepIDMapping()
+		if err != nil {
+			return err
+		}
+		g.SetProcessUID(uint32(uid))
+		g.SetProcessGID(uint32(gid))
+		fallthrough
 	case specgen.Private:
 		if err := g.AddOrReplaceLinuxNamespace(string(spec.UserNamespace), ""); err != nil {
 			return err
diff --git a/pkg/specgen/namespaces.go b/pkg/specgen/namespaces.go
index fffbd6d9e..cee49ff51 100644
--- a/pkg/specgen/namespaces.go
+++ b/pkg/specgen/namespaces.go
@@ -76,6 +76,17 @@ func (n *Namespace) IsPod() bool {
 func (n *Namespace) IsPrivate() bool {
 	return n.NSMode == Private
 }
+
+// IsAuto indicates the namespace is auto
+func (n *Namespace) IsAuto() bool {
+	return n.NSMode == Auto
+}
+
+// IsKeepID indicates the namespace is KeepID
+func (n *Namespace) IsKeepID() bool {
+	return n.NSMode == KeepID
+}
+
 func validateUserNS(n *Namespace) error {
 	if n == nil {
 		return nil
@@ -186,12 +197,11 @@ func ParseUserNamespace(ns string) (Namespace, error) {
 		if len(split) != 2 {
 			return toReturn, errors.Errorf("invalid setting for auto: mode")
 		}
-		toReturn.NSMode = KeepID
+		toReturn.NSMode = Auto
 		toReturn.Value = split[1]
 		return toReturn, nil
 	case ns == "keep-id":
 		toReturn.NSMode = KeepID
-		toReturn.NSMode = FromContainer
 		return toReturn, nil
 	}
 	return ParseNamespace(ns)