Merge pull request #2020 from Luap99/rootlessnetns-env

libnetwork: fix rexec env check for rootlessnetns

common/libnetwork/cni/network.go

@@ -82,9 +82,23 @@ type InitConfig struct {
 // NewCNINetworkInterface creates the ContainerNetwork interface for the CNI backend.
 // Note: The networks are not loaded from disk until a method is called.
 func NewCNINetworkInterface(conf *InitConfig) (types.ContainerNetwork, error) {
+	var netns *rootlessnetns.Netns
+	var err error
+	// Do not use unshare.IsRootless() here. We only care if we are running re-exec in the userns,
+	// IsRootless() also returns true if we are root in a userns which is not what we care about and
+	// causes issues as this slower more complicated rootless-netns logic should not be used as root.
+	val, ok := os.LookupEnv(unshare.UsernsEnvName)
+	useRootlessNetns := ok && val == "done"
+	if useRootlessNetns {
+		netns, err = rootlessnetns.New(conf.RunDir, rootlessnetns.CNI, conf.Config)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	// root needs to use a globally unique lock because there is only one host netns
 	lockPath := defaultRootLockPath
-	if unshare.IsRootless() {
+	if useRootlessNetns {
 		lockPath = filepath.Join(conf.CNIConfigDir, "cni.lock")
 	}
 
@@ -112,14 +126,6 @@ func NewCNINetworkInterface(conf *InitConfig) (types.ContainerNetwork, error) {
 		defaultSubnetPools = config.DefaultSubnetPools
 	}
 
-	var netns *rootlessnetns.Netns
-	if unshare.IsRootless() {
-		netns, err = rootlessnetns.New(conf.RunDir, rootlessnetns.CNI, conf.Config)
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	cni := libcni.NewCNIConfig(conf.Config.Network.CNIPluginDirs.Values, &cniExec{})
 	n := &cniNetwork{
 		cniConfigDir:       conf.CNIConfigDir,

common/libnetwork/netavark/network.go

@@ -96,9 +96,23 @@ type InitConfig struct {
 // NewNetworkInterface creates the ContainerNetwork interface for the netavark backend.
 // Note: The networks are not loaded from disk until a method is called.
 func NewNetworkInterface(conf *InitConfig) (types.ContainerNetwork, error) {
+	var netns *rootlessnetns.Netns
+	var err error
+	// Do not use unshare.IsRootless() here. We only care if we are running re-exec in the userns,
+	// IsRootless() also returns true if we are root in a userns which is not what we care about and
+	// causes issues as this slower more complicated rootless-netns logic should not be used as root.
+	val, ok := os.LookupEnv(unshare.UsernsEnvName)
+	useRootlessNetns := ok && val == "done"
+	if useRootlessNetns {
+		netns, err = rootlessnetns.New(conf.NetworkRunDir, rootlessnetns.Netavark, conf.Config)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	// root needs to use a globally unique lock because there is only one host netns
 	lockPath := defaultRootLockPath
-	if unshare.IsRootless() {
+	if useRootlessNetns {
 		lockPath = filepath.Join(conf.NetworkConfigDir, "netavark.lock")
 	}
 
@@ -134,18 +148,6 @@ func NewNetworkInterface(conf *InitConfig) (types.ContainerNetwork, error) {
 		defaultSubnetPools = config.DefaultSubnetPools
 	}
 
-	var netns *rootlessnetns.Netns
-	// Do not use unshare.IsRootless() here. We only care if we are running re-exec in the userns,
-	// IsRootless() also returns true if we are root in a userns which is not what we care about and
-	// causes issues as this slower more complicated rootless-netns logic should not be used as root.
-	_, useRootlessNetns := os.LookupEnv(unshare.UsernsEnvName)
-	if useRootlessNetns {
-		netns, err = rootlessnetns.New(conf.NetworkRunDir, rootlessnetns.Netavark, conf.Config)
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	n := &netavarkNetwork{
 		networkConfigDir:   conf.NetworkConfigDir,
 		networkRunDir:      conf.NetworkRunDir,