rootless: Rearrange setup of rootless containers

In order to run Podman with VM-based runtimes unprivileged, the
network must be set up prior to the container creation. Therefore
this commit modifies Podman to run rootless containers by:
  1. create a network namespace
  2. pass the netns persistent mount path to the slirp4netns
     to create the tap inferface
  3. pass the netns path to the OCI spec, so the runtime can
     enter the netns

Closes #2897

Signed-off-by: Gabi Beyer <gabrielle.n.beyer@intel.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 230b5b888..e7b4b2b22 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -78,15 +78,21 @@ func (c *Container) prepare() (Err error) {
 		// Set up network namespace if not already set up
 		if c.config.CreateNetNS && c.state.NetNS == nil && !c.config.PostConfigureNetNS {
 			netNS, networkStatus, createNetNSErr = c.runtime.createNetNS(c)
+			if createNetNSErr != nil {
+				return
+			}
 
 			tmpStateLock.Lock()
 			defer tmpStateLock.Unlock()
 
 			// Assign NetNS attributes to container
-			if createNetNSErr == nil {
-				c.state.NetNS = netNS
-				c.state.NetworkStatus = networkStatus
-			}
+			c.state.NetNS = netNS
+			c.state.NetworkStatus = networkStatus
+		}
+
+		// handle rootless network namespace setup
+		if c.state.NetNS != nil && c.config.NetMode == "slirp4netns" && !c.config.PostConfigureNetNS {
+			createNetNSErr = c.runtime.setupRootlessNetNS(c)
 		}
 	}()
 	// Mount storage if not mounted