From 0ca62196a0432355365ba2db0c20934fa36d8039 Mon Sep 17 00:00:00 2001 From: Paul Holzinger Date: Tue, 14 Sep 2021 11:13:28 +0200 Subject: libpod: rootful close binded ports For rootful users ports are forwarded via iptables. To make sure no other process tries to use them, libpod will bind the ports and pass the fds to conmon. There seems to be race when a container is restarted because libpod tries to bind the port before the conmon process exited. The problem only hapens with the podman service because it keeps the connection open. Once we have the fd and passed it to conmon the podman service should close the connection. To verify run `sudo ss -tulpn` and check that only the conmon process keeps the port open. Previously you would also see the podman server process listed. Signed-off-by: Paul Holzinger --- libpod/oci_conmon_linux.go | 1 + libpod/oci_util.go | 13 +++++++++++++ 2 files changed, 14 insertions(+) diff --git a/libpod/oci_conmon_linux.go b/libpod/oci_conmon_linux.go index 924df2310..8a823e4fc 100644 --- a/libpod/oci_conmon_linux.go +++ b/libpod/oci_conmon_linux.go @@ -1138,6 +1138,7 @@ func (r *ConmonOCIRuntime) createOCIContainer(ctr *Container, restoreOptions *Co if err != nil { return err } + filesToClose = append(filesToClose, ports...) // Leak the port we bound in the conmon process. These fd's won't be used // by the container and conmon will keep the ports busy so that another diff --git a/libpod/oci_util.go b/libpod/oci_util.go index 1cafd5863..f2843b09b 100644 --- a/libpod/oci_util.go +++ b/libpod/oci_util.go @@ -68,6 +68,12 @@ func bindPorts(ports []ocicni.PortMapping) ([]*os.File, error) { return nil, errors.Wrapf(err, "cannot get file for UDP socket") } files = append(files, f) + // close the listener + // note that this does not affect the fd, see the godoc for server.File() + err = server.Close() + if err != nil { + logrus.Warnf("failed to close connection: %v", err) + } case "tcp": var ( @@ -96,6 +102,13 @@ func bindPorts(ports []ocicni.PortMapping) ([]*os.File, error) { return nil, errors.Wrapf(err, "cannot get file for TCP socket") } files = append(files, f) + // close the listener + // note that this does not affect the fd, see the godoc for server.File() + err = server.Close() + if err != nil { + logrus.Warnf("failed to close connection: %v", err) + } + case "sctp": if !notifySCTP { notifySCTP = true -- cgit v1.2.3-54-g00ecf