create: join also the mount ns of the dependency

when we are creating a container that depends on another one, be sure
we also join its mount namespace in addition to the user namespace.

Closes: https://github.com/containers/libpod/issues/2556

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

1 files changed, 10 insertions, 1 deletions

diff --git a/cmd/podman/create.go b/cmd/podman/create.go
index a7b9bbf31..9e9073a1d 100644
--- a/cmd/podman/create.go
+++ b/cmd/podman/create.go
@@ -894,7 +894,16 @@ func joinOrCreateRootlessUserNamespace(createConfig *cc.CreateConfig, runtime *l
 				}
 				return false, -1, errors.Errorf("dependency container %s is not running", ctr.ID())
 			}
-			return rootless.JoinNS(uint(pid), 0)
+
+			data, err := ioutil.ReadFile(ctr.Config().ConmonPidFile)
+			if err != nil {
+				return false, -1, errors.Wrapf(err, "cannot read conmon PID file %q", ctr.Config().ConmonPidFile)
+			}
+			conmonPid, err := strconv.Atoi(string(data))
+			if err != nil {
+				return false, -1, errors.Wrapf(err, "cannot parse PID %q", data)
+			}
+			return rootless.JoinDirectUserAndMountNS(uint(conmonPid))
 		}
 	}
 	return rootless.BecomeRootInUserNS()