Add support for pod inside of user namespace.

Add the --userns flag to podman pod create and keep
track of the userns setting that pod was created with
so that all containers created within the pod will inherit
that userns setting.

Specifically we need to be able to launch a pod with
--userns=keep-id

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
Signed-off-by: Urvashi Mohnani <umohnani@redhat.com>

22 files changed, 421 insertions, 60 deletions

diff --git a/cmd/podman/containers/create.go b/cmd/podman/containers/create.go
index 895736144..906ae4452 100644
--- a/cmd/podman/containers/create.go
+++ b/cmd/podman/containers/create.go
@@ -184,6 +184,9 @@ func createInit(c *cobra.Command) error {
 	if c.Flag("cpu-quota").Changed && c.Flag("cpus").Changed {
 		return errors.Errorf("--cpu-quota and --cpus cannot be set together")
 	}
+	if c.Flag("pod").Changed && !strings.HasPrefix(c.Flag("pod").Value.String(), "new:") && c.Flag("userns").Changed {
+		return errors.Errorf("--userns and --pod cannot be set together")
+	}
 
 	noHosts, err := c.Flags().GetBool("no-hosts")
 	if err != nil {
@@ -309,6 +312,12 @@ func createPodIfNecessary(s *specgen.SpecGenerator, netOpts *entities.NetOptions
 	if len(podName) < 1 {
 		return nil, errors.Errorf("new pod name must be at least one character")
 	}
+
+	userns, err := specgen.ParseUserNamespace(cliVals.UserNS)
+	if err != nil {
+		return nil, err
+	}
+
 	createOptions := entities.PodCreateOptions{
 		Name:          podName,
 		Infra:         true,
@@ -318,6 +327,7 @@ func createPodIfNecessary(s *specgen.SpecGenerator, netOpts *entities.NetOptions
 		Cpus:          cliVals.CPUS,
 		CpusetCpus:    cliVals.CPUSetCPUs,
 		Pid:           cliVals.PID,
+		Userns:        userns,
 	}
 	// Unset config values we passed to the pod to prevent them being used twice for the container and pod.
 	s.ContainerBasicConfig.Hostname = ""
diff --git a/cmd/podman/pods/create.go b/cmd/podman/pods/create.go
index abc47164b..bf5b9e350 100644
--- a/cmd/podman/pods/create.go
+++ b/cmd/podman/pods/create.go
@@ -48,6 +48,7 @@ var (
 	podIDFile         string
 	replace           bool
 	share             string
+	userns            string
 )
 
 func init() {
@@ -72,6 +73,10 @@ func init() {
 	flags.StringVar(&createOptions.CGroupParent, cgroupParentflagName, "", "Set parent cgroup for the pod")
 	_ = createCommand.RegisterFlagCompletionFunc(cgroupParentflagName, completion.AutocompleteDefault)
 
+	usernsFlagName := "userns"
+	flags.StringVar(&userns, usernsFlagName, os.Getenv("PODMAN_USERNS"), "User namespace to use")
+	_ = createCommand.RegisterFlagCompletionFunc(usernsFlagName, common.AutocompleteUserNamespace)
+
 	flags.BoolVar(&createOptions.Infra, "infra", true, "Create an infra container associated with the pod to share namespaces with")
 
 	infraConmonPidfileFlagName := "infra-conmon-pidfile"
@@ -178,6 +183,11 @@ func create(cmd *cobra.Command, args []string) error {
 		}
 	}
 
+	createOptions.Userns, err = specgen.ParseUserNamespace(userns)
+	if err != nil {
+		return err
+	}
+
 	if cmd.Flag("pod-id-file").Changed {
 		podIDFD, err = util.OpenExclusiveFile(podIDFile)
 		if err != nil && os.IsExist(err) {
diff --git a/docs/source/markdown/podman-create.1.md b/docs/source/markdown/podman-create.1.md
index 51f51c10a..86cabb9a8 100644
--- a/docs/source/markdown/podman-create.1.md
+++ b/docs/source/markdown/podman-create.1.md
@@ -1123,9 +1123,9 @@ Podman allocates unique ranges of UIDs and GIDs from the `containers` subpordina
 
   Valid `auto`options:
 
-  - *gidmapping*=_HOST_GID:CONTAINER_GID:SIZE_: to force a GID mapping to be present in the user namespace.
+  - *gidmapping*=_CONTAINER_GID:HOST_GID:SIZE_: to force a GID mapping to be present in the user namespace.
   - *size*=_SIZE_: to specify an explicit size for the automatic user namespace. e.g. `--userns=auto:size=8192`. If `size` is not specified, `auto` will estimate a size for the user namespace.
-  - *uidmapping*=_HOST_UID:CONTAINER_UID:SIZE_: to force a UID mapping to be present in the user namespace.
+  - *uidmapping*=_CONTAINER_UID:HOST_UID:SIZE_: to force a UID mapping to be present in the user namespace.
 
 **container:**_id_: join the user namespace of the specified container.
 
diff --git a/docs/source/markdown/podman-pod-create.1.md b/docs/source/markdown/podman-pod-create.1.md
index 441995cb6..04a23fb53 100644
--- a/docs/source/markdown/podman-pod-create.1.md
+++ b/docs/source/markdown/podman-pod-create.1.md
@@ -164,6 +164,19 @@ podman generates a UUID for each pod, and if a name is not assigned
 to the container with **--name** then a random string name will be generated
 for it. The name is useful any place you need to identify a pod.
 
+#### **--userns**=*mode*
+
+Set the user namespace mode for all the containers in a pod. It defaults to the **PODMAN_USERNS** environment variable. An empty value ("") means user namespaces are disabled.
+
+Valid _mode_ values are:
+
+- *auto[:*_OPTIONS,..._*]*: automatically create a namespace. It is possible to specify these options to `auto`:
+  - *gidmapping=*_CONTAINER_GID:HOST_GID:SIZE_ to force a GID mapping to be present in the user namespace.
+  - *size=*_SIZE_: to specify an explicit size for the automatic user namespace. e.g. `--userns=auto:size=8192`. If `size` is not specified, `auto` will estimate a size for the user namespace.
+  - *uidmapping=*_CONTAINER_UID:HOST_UID:SIZE_ to force a UID mapping to be present in the user namespace.
+- *host*: run in the user namespace of the caller. The processes running in the container will have the same privileges on the host as any other process launched by the calling user (default).
+- *keep-id*: creates a user namespace where the current rootless user's UID:GID are mapped to the same values in the container. This option is ignored for containers created by the root user.
+
 ## EXAMPLES
 
 ```
diff --git a/docs/source/markdown/podman-run.1.md b/docs/source/markdown/podman-run.1.md
index 38ed44582..6a7489609 100644
--- a/docs/source/markdown/podman-run.1.md
+++ b/docs/source/markdown/podman-run.1.md
@@ -1181,9 +1181,9 @@ Podman allocates unique ranges of UIDs and GIDs from the `containers` subpordina
 
   Valid `auto`options:
 
-  - *gidmapping*=_HOST_GID:CONTAINER_GID:SIZE_: to force a GID mapping to be present in the user namespace.
+  - *gidmapping*=_CONTAINER_GID:HOST_GID:SIZE_: to force a GID mapping to be present in the user namespace.
   - *size*=_SIZE_: to specify an explicit size for the automatic user namespace. e.g. `--userns=auto:size=8192`. If `size` is not specified, `auto` will estimate a size for the user namespace.
-  - *uidmapping*=_HOST_UID:CONTAINER_UID:SIZE_: to force a UID mapping to be present in the user namespace.
+  - *uidmapping*=_CONTAINER_UID:HOST_UID:SIZE_: to force a UID mapping to be present in the user namespace.
 
 **container:**_id_: join the user namespace of the specified container.
 
diff --git a/libpod/container.go b/libpod/container.go
index f3f4b27b7..d5d5ef1a5 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -1020,8 +1020,8 @@ func (c *Container) RWSize() (int64, error) {
 }
 
 // IDMappings returns the UID/GID mapping used for the container
-func (c *Container) IDMappings() (storage.IDMappingOptions, error) {
-	return c.config.IDMappings, nil
+func (c *Container) IDMappings() storage.IDMappingOptions {
+	return c.config.IDMappings
 }
 
 // RootUID returns the root user mapping from container
diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index 8ffcccf4c..3f7a4807d 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -367,6 +367,12 @@ func (c *Container) setupStorageMapping(dest, from *storage.IDMappingOptions) {
 		return
 	}
 	*dest = *from
+	// If we are creating a container inside a pod, we always want to inherit the
+	// userns settings from the infra container. So clear the auto userns settings
+	// so that we don't request storage for a new uid/gid map.
+	if c.PodID() != "" && !c.IsInfra() {
+		dest.AutoUserNs = false
+	}
 	if dest.AutoUserNs {
 		overrides := c.getUserOverrides()
 		dest.AutoUserNsOpts.PasswdFile = overrides.ContainerEtcPasswdPath
diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index f30f622ac..6d2f7bddc 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -659,7 +659,7 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 		}
 	}
 
-	if c.config.IDMappings.AutoUserNs {
+	if c.config.UserNsCtr == "" && c.config.IDMappings.AutoUserNs {
 		if err := g.AddOrReplaceLinuxNamespace(string(spec.UserNamespace), ""); err != nil {
 			return nil, err
 		}
@@ -1884,7 +1884,7 @@ func (c *Container) generateResolvConf() (string, error) {
 		return "", err
 	}
 
-	return filepath.Join(c.state.RunDir, "resolv.conf"), nil
+	return destPath, nil
 }
 
 // generateHosts creates a containers hosts file
diff --git a/libpod/define/pod_inspect.go b/libpod/define/pod_inspect.go
index a17304875..f91fd198d 100644
--- a/libpod/define/pod_inspect.go
+++ b/libpod/define/pod_inspect.go
@@ -105,6 +105,8 @@ type InspectPodInfraConfig struct {
 	CPUSetCPUs string `json:"cpuset_cpus,omitempty"`
 	// Pid is the PID namespace mode of the pod's infra container
 	PidNS string `json:"pid_ns,omitempty"`
+	// UserNS is the usernamespace that all the containers in the pod will join.
+	UserNS string `json:"userns,omitempty"`
 }
 
 // InspectPodContainerInfo contains information on a container in a pod.
diff --git a/libpod/options.go b/libpod/options.go
index 071b085e7..b94ef88ba 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -956,8 +956,9 @@ func WithUserNSFrom(nsCtr *Container) CtrCreateOption {
 		}
 
 		ctr.config.UserNsCtr = nsCtr.ID()
-		ctr.config.IDMappings = nsCtr.config.IDMappings
-
+		if err := JSONDeepCopy(nsCtr.IDMappings(), &ctr.config.IDMappings); err != nil {
+			return err
+		}
 		g := generate.Generator{Config: ctr.config.Spec}
 
 		g.ClearLinuxUIDMappings()
@@ -968,7 +969,6 @@ func WithUserNSFrom(nsCtr *Container) CtrCreateOption {
 		for _, gidmap := range nsCtr.config.IDMappings.GIDMap {
 			g.AddLinuxGIDMapping(uint32(gidmap.HostID), uint32(gidmap.ContainerID), uint32(gidmap.Size))
 		}
-		ctr.config.IDMappings = nsCtr.config.IDMappings
 		return nil
 	}
 }
@@ -2423,6 +2423,24 @@ func WithVolatile() CtrCreateOption {
 		}
 
 		ctr.config.Volatile = true
+
+		return nil
+	}
+}
+
+// WithPodUserns sets the userns for the infra container in a pod.
+func WithPodUserns(userns specgen.Namespace) PodCreateOption {
+	return func(pod *Pod) error {
+		if pod.valid {
+			return define.ErrPodFinalized
+		}
+
+		if !pod.config.InfraContainer.HasInfraContainer {
+			return errors.Wrapf(define.ErrInvalidArg, "cannot configure pod userns as no infra container is being created")
+		}
+
+		pod.config.InfraContainer.Userns = userns
+
 		return nil
 	}
 }
diff --git a/libpod/pod.go b/libpod/pod.go
index 0fef7f6f3..7df15df7b 100644
--- a/libpod/pod.go
+++ b/libpod/pod.go
@@ -117,6 +117,7 @@ type InfraContainerConfig struct {
 	Slirp4netns        bool                  `json:"slirp4netns,omitempty"`
 	NetworkOptions     map[string][]string   `json:"network_options,omitempty"`
 	ResourceLimits     *specs.LinuxResources `json:"resource_limits,omitempty"`
+	Userns             specgen.Namespace     `json:"userns,omitempty"`
 }
 
 // ID retrieves the pod's ID
diff --git a/libpod/pod_api.go b/libpod/pod_api.go
index 90d67dbb0..6fea2dfd8 100644
--- a/libpod/pod_api.go
+++ b/libpod/pod_api.go
@@ -593,6 +593,7 @@ func (p *Pod) Inspect() (*define.InspectPodData, error) {
 		infraConfig.CPUQuota = p.CPUQuota()
 		infraConfig.CPUSetCPUs = p.ResourceLim().CPU.Cpus
 		infraConfig.PidNS = p.PidMode()
+		infraConfig.UserNS = p.config.InfraContainer.Userns.String()
 
 		if len(p.config.InfraContainer.DNSServer) > 0 {
 			infraConfig.DNSServer = make([]string, 0, len(p.config.InfraContainer.DNSServer))
diff --git a/libpod/runtime_pod_infra_linux.go b/libpod/runtime_pod_infra_linux.go
index d4f861118..49213032e 100644
--- a/libpod/runtime_pod_infra_linux.go
+++ b/libpod/runtime_pod_infra_linux.go
@@ -8,7 +8,9 @@ import (
 
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/podman/v3/libpod/define"
+	"github.com/containers/podman/v3/pkg/namespaces"
 	"github.com/containers/podman/v3/pkg/rootless"
+	"github.com/containers/podman/v3/pkg/specgen"
 	"github.com/containers/podman/v3/pkg/util"
 	v1 "github.com/opencontainers/image-spec/specs-go/v1"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
@@ -110,9 +112,7 @@ func (r *Runtime) makeInfraContainer(ctx context.Context, p *Pod, imgName, rawIm
 					options = append(options, WithNetworkOptions(p.config.InfraContainer.NetworkOptions))
 				}
 			}
-			// PostConfigureNetNS should not be set since user namespace sharing is not implemented
-			// and rootless networking no longer supports post configuration setup
-			options = append(options, WithNetNS(p.config.InfraContainer.PortBindings, false, netmode, p.config.InfraContainer.Networks))
+			options = append(options, WithNetNS(p.config.InfraContainer.PortBindings, !p.config.InfraContainer.Userns.IsHost(), netmode, p.config.InfraContainer.Networks))
 		}
 
 		// For each option in InfraContainerConfig - if set, pass into
@@ -158,11 +158,39 @@ func (r *Runtime) makeInfraContainer(ctx context.Context, p *Pod, imgName, rawIm
 			g.Config.Linux.Namespaces = newNS
 		}
 	}
+
+	for _, ctl := range r.config.Containers.DefaultSysctls {
+		sysctl := strings.SplitN(ctl, "=", 2)
+		if len(sysctl) < 2 {
+			return nil, errors.Errorf("invalid default sysctl %s", ctl)
+		}
+
+		// Ignore net sysctls if --net=host
+		if p.config.InfraContainer.HostNetwork && strings.HasPrefix(sysctl[0], "net.") {
+			logrus.Infof("Sysctl %s=%s ignored in containers.conf, since Network Namespace set to host", sysctl[0], sysctl[1])
+			continue
+		}
+
+		g.AddLinuxSysctl(sysctl[0], sysctl[1])
+	}
+
 	g.SetRootReadonly(true)
 	g.SetProcessArgs(infraCtrCommand)
 
 	logrus.Debugf("Using %q as infra container command", infraCtrCommand)
 
+	mapopt, err := util.ParseIDMapping(namespaces.UsernsMode(p.config.InfraContainer.Userns.String()), []string{}, []string{}, "", "")
+	if err != nil {
+		return nil, err
+	}
+	user, err := specgen.SetupUserNS(mapopt, p.config.InfraContainer.Userns, &g)
+	if err != nil {
+		return nil, err
+	}
+	if user != "" {
+		options = append(options, WithUser(user))
+	}
+
 	g.RemoveMount("/dev/shm")
 	if isRootless {
 		g.RemoveMount("/dev/pts")
@@ -210,14 +238,15 @@ func (r *Runtime) makeInfraContainer(ctx context.Context, p *Pod, imgName, rawIm
 	options = append(options, WithRootFSFromImage(imgID, imgName, rawImageName))
 	options = append(options, WithName(containerName))
 	options = append(options, withIsInfra())
+	options = append(options, WithIDMappings(*mapopt))
 	if len(p.config.InfraContainer.ConmonPidFile) > 0 {
 		options = append(options, WithConmonPidFile(p.config.InfraContainer.ConmonPidFile))
 	}
 	newRes := new(spec.LinuxResources)
 	newRes.CPU = new(spec.LinuxCPU)
 	newRes.CPU = p.ResourceLim().CPU
-
 	g.Config.Linux.Resources.CPU = newRes.CPU
+
 	return r.newContainer(ctx, g.Config, options...)
 }
 
diff --git a/pkg/api/handlers/libpod/pods.go b/pkg/api/handlers/libpod/pods.go
index 4dc8740e2..ff105bc48 100644
--- a/pkg/api/handlers/libpod/pods.go
+++ b/pkg/api/handlers/libpod/pods.go
@@ -30,6 +30,12 @@ func PodCreate(w http.ResponseWriter, r *http.Request) {
 		utils.Error(w, "failed to decode specgen", http.StatusInternalServerError, errors.Wrap(err, "failed to decode specgen"))
 		return
 	}
+	// parse userns so we get the valid default value of userns
+	psg.Userns, err = specgen.ParseUserNamespace(psg.Userns.String())
+	if err != nil {
+		utils.Error(w, "failed to parse userns", http.StatusInternalServerError, errors.Wrap(err, "failed to parse userns"))
+		return
+	}
 	pod, err := generate.MakePod(&psg, runtime)
 	if err != nil {
 		httpCode := http.StatusInternalServerError
diff --git a/pkg/domain/entities/pods.go b/pkg/domain/entities/pods.go
index 68e335f8d..c66bf96fc 100644
--- a/pkg/domain/entities/pods.go
+++ b/pkg/domain/entities/pods.go
@@ -122,6 +122,7 @@ type PodCreateOptions struct {
 	Pid                string
 	Cpus               float64
 	CpusetCpus         string
+	Userns             specgen.Namespace
 }
 
 type PodCreateReport struct {
@@ -217,6 +218,7 @@ func (p *PodCreateOptions) ToPodSpecGen(s *specgen.PodSpecGenerator) error {
 			s.CPUQuota = *cpuDat.Quota
 		}
 	}
+	s.Userns = p.Userns
 	return nil
 }
 
diff --git a/pkg/specgen/generate/kube/kube.go b/pkg/specgen/generate/kube/kube.go
index fb7eb99a2..d6d479c67 100644
--- a/pkg/specgen/generate/kube/kube.go
+++ b/pkg/specgen/generate/kube/kube.go
@@ -303,6 +303,8 @@ func ToSpecGen(ctx context.Context, opts *CtrSpecGenOptions) (*specgen.SpecGener
 	if opts.NetNSIsHost {
 		s.NetNS.NSMode = specgen.Host
 	}
+	// Always set the userns to host since k8s doesn't have support for userns yet
+	s.UserNS.NSMode = specgen.Host
 
 	// Add labels that come from kube
 	if len(s.Labels) == 0 {
diff --git a/pkg/specgen/generate/namespaces.go b/pkg/specgen/generate/namespaces.go
index f41186ae4..1d7373093 100644
--- a/pkg/specgen/generate/namespaces.go
+++ b/pkg/specgen/generate/namespaces.go
@@ -175,6 +175,11 @@ func namespaceOptions(ctx context.Context, s *specgen.SpecGenerator, rt *libpod.
 		if pod == nil || infraCtr == nil {
 			return nil, errNoInfra
 		}
+		// Inherit the user from the infra container if it is set and --user has not
+		// been set explicitly
+		if infraCtr.User() != "" && s.User == "" {
+			toReturn = append(toReturn, libpod.WithUser(infraCtr.User()))
+		}
 		toReturn = append(toReturn, libpod.WithUserNSFrom(infraCtr))
 	case specgen.FromContainer:
 		userCtr, err := rt.LookupContainer(s.UserNS.Value)
@@ -184,7 +189,10 @@ func namespaceOptions(ctx context.Context, s *specgen.SpecGenerator, rt *libpod.
 		toReturn = append(toReturn, libpod.WithUserNSFrom(userCtr))
 	}
 
-	if s.IDMappings != nil {
+	// This wipes the UserNS settings that get set from the infra container
+	// when we are inheritting from the pod. So only apply this if the container
+	// is not being created in a pod.
+	if s.IDMappings != nil && pod == nil {
 		toReturn = append(toReturn, libpod.WithIDMappings(*s.IDMappings))
 	}
 	if s.User != "" {
@@ -379,46 +387,8 @@ func specConfigureNamespaces(s *specgen.SpecGenerator, g *generate.Generator, rt
 	}
 
 	// User
-	switch s.UserNS.NSMode {
-	case specgen.Path:
-		if _, err := os.Stat(s.UserNS.Value); err != nil {
-			return errors.Wrap(err, "cannot find specified user namespace path")
-		}
-		if err := g.AddOrReplaceLinuxNamespace(string(spec.UserNamespace), s.UserNS.Value); err != nil {
-			return err
-		}
-		// runc complains if no mapping is specified, even if we join another ns.  So provide a dummy mapping
-		g.AddLinuxUIDMapping(uint32(0), uint32(0), uint32(1))
-		g.AddLinuxGIDMapping(uint32(0), uint32(0), uint32(1))
-	case specgen.Host:
-		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
-		}
-		if s.IDMappings == nil || (len(s.IDMappings.UIDMap) == 0 && len(s.IDMappings.GIDMap) == 0) {
-			return errors.Errorf("must provide at least one UID or GID mapping to configure a user namespace")
-		}
-		for _, uidmap := range s.IDMappings.UIDMap {
-			g.AddLinuxUIDMapping(uint32(uidmap.HostID), uint32(uidmap.ContainerID), uint32(uidmap.Size))
-		}
-		for _, gidmap := range s.IDMappings.GIDMap {
-			g.AddLinuxGIDMapping(uint32(gidmap.HostID), uint32(gidmap.ContainerID), uint32(gidmap.Size))
-		}
+	if _, err := specgen.SetupUserNS(s.IDMappings, s.UserNS, g); err != nil {
+		return err
 	}
 
 	// Cgroup
@@ -474,7 +444,7 @@ func specConfigureNamespaces(s *specgen.SpecGenerator, g *generate.Generator, rt
 // GetNamespaceOptions transforms a slice of kernel namespaces
 // into a slice of pod create options. Currently, not all
 // kernel namespaces are supported, and they will be returned in an error
-func GetNamespaceOptions(ns []string) ([]libpod.PodCreateOption, error) {
+func GetNamespaceOptions(ns []string, netnsIsHost bool) ([]libpod.PodCreateOption, error) {
 	var options []libpod.PodCreateOption
 	var erroredOptions []libpod.PodCreateOption
 	if ns == nil {
@@ -486,7 +456,10 @@ func GetNamespaceOptions(ns []string) ([]libpod.PodCreateOption, error) {
 		case "cgroup":
 			options = append(options, libpod.WithPodCgroups())
 		case "net":
-			options = append(options, libpod.WithPodNet())
+			// share the netns setting with other containers in the pod only when it is not set to host
+			if !netnsIsHost {
+				options = append(options, libpod.WithPodNet())
+			}
 		case "mnt":
 			return erroredOptions, errors.Errorf("Mount sharing functionality not supported on pod level")
 		case "pid":
diff --git a/pkg/specgen/generate/pod_create.go b/pkg/specgen/generate/pod_create.go
index aab29499e..426cf1b6d 100644
--- a/pkg/specgen/generate/pod_create.go
+++ b/pkg/specgen/generate/pod_create.go
@@ -27,11 +27,16 @@ func createPodOptions(p *specgen.PodSpecGenerator, rt *libpod.Runtime) ([]libpod
 	)
 	if !p.NoInfra {
 		options = append(options, libpod.WithInfraContainer())
-		nsOptions, err := GetNamespaceOptions(p.SharedNamespaces)
+		nsOptions, err := GetNamespaceOptions(p.SharedNamespaces, p.NetNS.IsHost())
 		if err != nil {
 			return nil, err
 		}
 		options = append(options, nsOptions...)
+		// Use pod user and infra userns only when --userns is not set to host
+		if !p.Userns.IsHost() {
+			options = append(options, libpod.WithPodUser())
+			options = append(options, libpod.WithPodUserns(p.Userns))
+		}
 
 		// Make our exit command
 		storageConfig := rt.StorageConfig()
@@ -154,5 +159,6 @@ func createPodOptions(p *specgen.PodSpecGenerator, rt *libpod.Runtime) ([]libpod
 	if len(p.InfraConmonPidFile) > 0 {
 		options = append(options, libpod.WithInfraConmonPidFile(p.InfraConmonPidFile))
 	}
+
 	return options, nil
 }
diff --git a/pkg/specgen/namespaces.go b/pkg/specgen/namespaces.go
index 76fa66bc7..2f4c48811 100644
--- a/pkg/specgen/namespaces.go
+++ b/pkg/specgen/namespaces.go
@@ -1,10 +1,16 @@
 package specgen
 
 import (
+	"fmt"
+	"os"
 	"strings"
 
 	"github.com/containers/podman/v3/pkg/cgroups"
 	"github.com/containers/podman/v3/pkg/rootless"
+	"github.com/containers/podman/v3/pkg/util"
+	"github.com/containers/storage"
+	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/opencontainers/runtime-tools/generate"
 	"github.com/pkg/errors"
 )
 
@@ -103,6 +109,13 @@ func (n *Namespace) IsKeepID() bool {
 	return n.NSMode == KeepID
 }
 
+func (n *Namespace) String() string {
+	if n.Value != "" {
+		return fmt.Sprintf("%s:%s", n.NSMode, n.Value)
+	}
+	return string(n.NSMode)
+}
+
 func validateUserNS(n *Namespace) error {
 	if n == nil {
 		return nil
@@ -323,3 +336,48 @@ func ParseNetworkString(network string) (Namespace, []string, map[string][]strin
 	}
 	return ns, cniNets, networkOptions, nil
 }
+
+func SetupUserNS(idmappings *storage.IDMappingOptions, userns Namespace, g *generate.Generator) (string, error) {
+	// User
+	var user string
+	switch userns.NSMode {
+	case Path:
+		if _, err := os.Stat(userns.Value); err != nil {
+			return user, errors.Wrap(err, "cannot find specified user namespace path")
+		}
+		if err := g.AddOrReplaceLinuxNamespace(string(spec.UserNamespace), userns.Value); err != nil {
+			return user, err
+		}
+		// runc complains if no mapping is specified, even if we join another ns.  So provide a dummy mapping
+		g.AddLinuxUIDMapping(uint32(0), uint32(0), uint32(1))
+		g.AddLinuxGIDMapping(uint32(0), uint32(0), uint32(1))
+	case Host:
+		if err := g.RemoveLinuxNamespace(string(spec.UserNamespace)); err != nil {
+			return user, err
+		}
+	case KeepID:
+		mappings, uid, gid, err := util.GetKeepIDMapping()
+		if err != nil {
+			return user, err
+		}
+		idmappings = mappings
+		g.SetProcessUID(uint32(uid))
+		g.SetProcessGID(uint32(gid))
+		user = fmt.Sprintf("%d:%d", uid, gid)
+		fallthrough
+	case Private:
+		if err := g.AddOrReplaceLinuxNamespace(string(spec.UserNamespace), ""); err != nil {
+			return user, err
+		}
+		if idmappings == nil || (len(idmappings.UIDMap) == 0 && len(idmappings.GIDMap) == 0) {
+			return user, errors.Errorf("must provide at least one UID or GID mapping to configure a user namespace")
+		}
+		for _, uidmap := range idmappings.UIDMap {
+			g.AddLinuxUIDMapping(uint32(uidmap.HostID), uint32(uidmap.ContainerID), uint32(uidmap.Size))
+		}
+		for _, gidmap := range idmappings.GIDMap {
+			g.AddLinuxGIDMapping(uint32(gidmap.HostID), uint32(gidmap.ContainerID), uint32(gidmap.Size))
+		}
+	}
+	return user, nil
+}
diff --git a/pkg/specgen/podspecgen.go b/pkg/specgen/podspecgen.go
index 02237afe9..893ebf675 100644
--- a/pkg/specgen/podspecgen.go
+++ b/pkg/specgen/podspecgen.go
@@ -67,6 +67,10 @@ type PodBasicConfig struct {
 	// Optional (defaults to private if unset). This sets the PID namespace of the infra container
 	// This configuration will then be shared with the entire pod if PID namespace sharing is enabled via --share
 	Pid Namespace `json:"pid,omitempty:"`
+	// Userns is used to indicate which kind of Usernamespace to enter.
+	// Any containers created within the pod will inherit the pod's userns settings.
+	// Optional
+	Userns Namespace `json:"userns,omitempty"`
 }
 
 // PodNetworkConfig contains networking configuration for a pod.
diff --git a/test/e2e/play_kube_test.go b/test/e2e/play_kube_test.go
index 66bfdefe7..e3096d932 100644
--- a/test/e2e/play_kube_test.go
+++ b/test/e2e/play_kube_test.go
@@ -1114,7 +1114,7 @@ var _ = Describe("Podman play kube", func() {
 	})
 
 	It("podman play kube should share ipc,net,uts when shareProcessNamespace is set", func() {
-		SkipIfRootless("Requires root priviledges for sharing few namespaces")
+		SkipIfRootless("Requires root privileges for sharing few namespaces")
 		err := writeYaml(sharedNamespacePodYaml, kubeYaml)
 		Expect(err).To(BeNil())
 
diff --git a/test/e2e/pod_create_test.go b/test/e2e/pod_create_test.go
index 4c6788b9d..f6f532ce9 100644
--- a/test/e2e/pod_create_test.go
+++ b/test/e2e/pod_create_test.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/user"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -621,4 +622,223 @@ ENTRYPOINT ["sleep","99999"]
 		Expect(podCreate).Should(ExitWithError())
 
 	})
+
+	It("podman pod create with --userns=keep-id", func() {
+		if os.Geteuid() == 0 {
+			Skip("Test only runs without root")
+		}
+
+		podName := "testPod"
+		podCreate := podmanTest.Podman([]string{"pod", "create", "--userns", "keep-id", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+
+		session := podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "id", "-u"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		uid := fmt.Sprintf("%d", os.Geteuid())
+		ok, _ := session.GrepString(uid)
+		Expect(ok).To(BeTrue())
+
+		// Check passwd
+		session = podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "id", "-un"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		u, err := user.Current()
+		Expect(err).To(BeNil())
+		ok, _ = session.GrepString(u.Name)
+		Expect(ok).To(BeTrue())
+
+		// root owns /usr
+		session = podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "stat", "-c%u", "/usr"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).To(Equal("0"))
+
+		// fail if --pod and --userns set together
+		session = podmanTest.Podman([]string{"run", "--pod", podName, "--userns", "keep-id", ALPINE, "id", "-u"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(125))
+	})
+
+	It("podman pod create with --userns=keep-id can add users", func() {
+		if os.Geteuid() == 0 {
+			Skip("Test only runs without root")
+		}
+
+		podName := "testPod"
+		podCreate := podmanTest.Podman([]string{"pod", "create", "--userns", "keep-id", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+
+		ctrName := "ctr-name"
+		session := podmanTest.Podman([]string{"run", "--pod", podName, "-d", "--stop-signal", "9", "--name", ctrName, fedoraMinimal, "sleep", "600"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		// container inside pod inherits user form infra container if --user is not set
+		// etc/passwd entry will look like 1000:*:1000:1000:container user:/:/bin/sh
+		exec1 := podmanTest.Podman([]string{"exec", ctrName, "cat", "/etc/passwd"})
+		exec1.WaitWithDefaultTimeout()
+		Expect(exec1).Should(Exit(0))
+		Expect(exec1.OutputToString()).To(ContainSubstring("container"))
+
+		exec2 := podmanTest.Podman([]string{"exec", ctrName, "useradd", "testuser"})
+		exec2.WaitWithDefaultTimeout()
+		Expect(exec2).Should(Exit(0))
+
+		exec3 := podmanTest.Podman([]string{"exec", ctrName, "cat", "/etc/passwd"})
+		exec3.WaitWithDefaultTimeout()
+		Expect(exec3).Should(Exit(0))
+		Expect(exec3.OutputToString()).To(ContainSubstring("testuser"))
+	})
+
+	It("podman pod create with --userns=auto", func() {
+		u, err := user.Current()
+		Expect(err).To(BeNil())
+		name := u.Name
+		if name == "root" {
+			name = "containers"
+		}
+
+		content, err := ioutil.ReadFile("/etc/subuid")
+		if err != nil {
+			Skip("cannot read /etc/subuid")
+		}
+		if !strings.Contains(string(content), name) {
+			Skip("cannot find mappings for the current user")
+		}
+
+		m := make(map[string]string)
+		for i := 0; i < 5; i++ {
+			podName := "testPod" + strconv.Itoa(i)
+			podCreate := podmanTest.Podman([]string{"pod", "create", "--userns=auto", "--name", podName})
+			podCreate.WaitWithDefaultTimeout()
+			Expect(podCreate).Should(Exit(0))
+
+			session := podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "cat", "/proc/self/uid_map"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+			l := session.OutputToString()
+			Expect(strings.Contains(l, "1024")).To(BeTrue())
+			m[l] = l
+		}
+		// check for no duplicates
+		Expect(len(m)).To(Equal(5))
+	})
+
+	It("podman pod create --userns=auto:size=%d", func() {
+		u, err := user.Current()
+		Expect(err).To(BeNil())
+
+		name := u.Name
+		if name == "root" {
+			name = "containers"
+		}
+
+		content, err := ioutil.ReadFile("/etc/subuid")
+		if err != nil {
+			Skip("cannot read /etc/subuid")
+		}
+		if !strings.Contains(string(content), name) {
+			Skip("cannot find mappings for the current user")
+		}
+
+		podName := "testPod"
+		podCreate := podmanTest.Podman([]string{"pod", "create", "--userns=auto:size=500", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+		session := podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "cat", "/proc/self/uid_map"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		ok, _ := session.GrepString("500")
+
+		podName = "testPod-1"
+		podCreate = podmanTest.Podman([]string{"pod", "create", "--userns=auto:size=3000", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+		session = podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "cat", "/proc/self/uid_map"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		ok, _ = session.GrepString("3000")
+
+		Expect(ok).To(BeTrue())
+	})
+
+	It("podman pod create --userns=auto:uidmapping=", func() {
+		u, err := user.Current()
+		Expect(err).To(BeNil())
+
+		name := u.Name
+		if name == "root" {
+			name = "containers"
+		}
+
+		content, err := ioutil.ReadFile("/etc/subuid")
+		if err != nil {
+			Skip("cannot read /etc/subuid")
+		}
+		if !strings.Contains(string(content), name) {
+			Skip("cannot find mappings for the current user")
+		}
+
+		podName := "testPod"
+		podCreate := podmanTest.Podman([]string{"pod", "create", "--userns=auto:uidmapping=0:0:1", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+		session := podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "cat", "/proc/self/uid_map"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		output := session.OutputToString()
+		Expect(output).To(MatchRegexp("\\s0\\s0\\s1"))
+
+		podName = "testPod-1"
+		podCreate = podmanTest.Podman([]string{"pod", "create", "--userns=auto:size=8192,uidmapping=0:0:1", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+		session = podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "cat", "/proc/self/uid_map"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		ok, _ := session.GrepString("8191")
+		Expect(ok).To(BeTrue())
+	})
+
+	It("podman pod create --userns=auto:gidmapping=", func() {
+		u, err := user.Current()
+		Expect(err).To(BeNil())
+
+		name := u.Name
+		if name == "root" {
+			name = "containers"
+		}
+
+		content, err := ioutil.ReadFile("/etc/subuid")
+		if err != nil {
+			Skip("cannot read /etc/subuid")
+		}
+		if !strings.Contains(string(content), name) {
+			Skip("cannot find mappings for the current user")
+		}
+
+		podName := "testPod"
+		podCreate := podmanTest.Podman([]string{"pod", "create", "--userns=auto:gidmapping=0:0:1", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+		session := podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "cat", "/proc/self/gid_map"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		output := session.OutputToString()
+		Expect(output).To(MatchRegexp("\\s0\\s0\\s1"))
+
+		podName = "testPod-1"
+		podCreate = podmanTest.Podman([]string{"pod", "create", "--userns=auto:size=8192,gidmapping=0:0:1", "--name", podName})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+		session = podmanTest.Podman([]string{"run", "--pod", podName, ALPINE, "cat", "/proc/self/gid_map"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		ok, _ := session.GrepString("8191")
+		Expect(ok).To(BeTrue())
+	})
+
 })