Netstack (#1403)

Add netstack support for the agent to run it without privileges.

- use interface for tun device
- use common IPC for userspace WireGuard integration
- move udpmux creation and sharedsock to tun layer

iface/wg_configurer_kernel.go

@@ -0,0 +1,209 @@
+//go:build linux && !android
+
+package iface
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"golang.zx2c4.com/wireguard/wgctrl"
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+)
+
+type wgKernelConfigurer struct {
+	deviceName string
+}
+
+func newWGConfigurer(deviceName string) wgConfigurer {
+	wgc := &wgKernelConfigurer{
+		deviceName: deviceName,
+	}
+	return wgc
+}
+
+func (c *wgKernelConfigurer) configureInterface(privateKey string, port int) error {
+	log.Debugf("adding Wireguard private key")
+	key, err := wgtypes.ParseKey(privateKey)
+	if err != nil {
+		return err
+	}
+	fwmark := 0
+	config := wgtypes.Config{
+		PrivateKey:   &key,
+		ReplacePeers: true,
+		FirewallMark: &fwmark,
+		ListenPort:   &port,
+	}
+
+	err = c.configure(config)
+	if err != nil {
+		return fmt.Errorf(`received error "%w" while configuring interface %s with port %d`, err, c.deviceName, port)
+	}
+	return nil
+}
+
+func (c *wgKernelConfigurer) updatePeer(peerKey string, allowedIps string, keepAlive time.Duration, endpoint *net.UDPAddr, preSharedKey *wgtypes.Key) error {
+	// parse allowed ips
+	_, ipNet, err := net.ParseCIDR(allowedIps)
+	if err != nil {
+		return err
+	}
+
+	peerKeyParsed, err := wgtypes.ParseKey(peerKey)
+	if err != nil {
+		return err
+	}
+	peer := wgtypes.PeerConfig{
+		PublicKey:                   peerKeyParsed,
+		ReplaceAllowedIPs:           true,
+		AllowedIPs:                  []net.IPNet{*ipNet},
+		PersistentKeepaliveInterval: &keepAlive,
+		PresharedKey:                preSharedKey,
+		Endpoint:                    endpoint,
+	}
+
+	config := wgtypes.Config{
+		Peers: []wgtypes.PeerConfig{peer},
+	}
+	err = c.configure(config)
+	if err != nil {
+		return fmt.Errorf(`received error "%w" while updating peer on interface %s with settings: allowed ips %s, endpoint %s`, err, c.deviceName, allowedIps, endpoint.String())
+	}
+	return nil
+}
+
+func (c *wgKernelConfigurer) removePeer(peerKey string) error {
+	peerKeyParsed, err := wgtypes.ParseKey(peerKey)
+	if err != nil {
+		return err
+	}
+
+	peer := wgtypes.PeerConfig{
+		PublicKey: peerKeyParsed,
+		Remove:    true,
+	}
+
+	config := wgtypes.Config{
+		Peers: []wgtypes.PeerConfig{peer},
+	}
+	err = c.configure(config)
+	if err != nil {
+		return fmt.Errorf(`received error "%w" while removing peer %s from interface %s`, err, peerKey, c.deviceName)
+	}
+	return nil
+}
+
+func (c *wgKernelConfigurer) addAllowedIP(peerKey string, allowedIP string) error {
+	_, ipNet, err := net.ParseCIDR(allowedIP)
+	if err != nil {
+		return err
+	}
+
+	peerKeyParsed, err := wgtypes.ParseKey(peerKey)
+	if err != nil {
+		return err
+	}
+	peer := wgtypes.PeerConfig{
+		PublicKey:         peerKeyParsed,
+		UpdateOnly:        true,
+		ReplaceAllowedIPs: false,
+		AllowedIPs:        []net.IPNet{*ipNet},
+	}
+
+	config := wgtypes.Config{
+		Peers: []wgtypes.PeerConfig{peer},
+	}
+	err = c.configure(config)
+	if err != nil {
+		return fmt.Errorf(`received error "%w" while adding allowed Ip to peer on interface %s with settings: allowed ips %s`, err, c.deviceName, allowedIP)
+	}
+	return nil
+}
+
+func (c *wgKernelConfigurer) removeAllowedIP(peerKey string, allowedIP string) error {
+	_, ipNet, err := net.ParseCIDR(allowedIP)
+	if err != nil {
+		return err
+	}
+
+	peerKeyParsed, err := wgtypes.ParseKey(peerKey)
+	if err != nil {
+		return err
+	}
+
+	existingPeer, err := c.getPeer(c.deviceName, peerKey)
+	if err != nil {
+		return err
+	}
+
+	newAllowedIPs := existingPeer.AllowedIPs
+
+	for i, existingAllowedIP := range existingPeer.AllowedIPs {
+		if existingAllowedIP.String() == ipNet.String() {
+			newAllowedIPs = append(existingPeer.AllowedIPs[:i], existingPeer.AllowedIPs[i+1:]...) //nolint:gocritic
+			break
+		}
+	}
+
+	peer := wgtypes.PeerConfig{
+		PublicKey:         peerKeyParsed,
+		UpdateOnly:        true,
+		ReplaceAllowedIPs: true,
+		AllowedIPs:        newAllowedIPs,
+	}
+
+	config := wgtypes.Config{
+		Peers: []wgtypes.PeerConfig{peer},
+	}
+	err = c.configure(config)
+	if err != nil {
+		return fmt.Errorf(`received error "%w" while removing allowed IP from peer on interface %s with settings: allowed ips %s`, err, c.deviceName, allowedIP)
+	}
+	return nil
+}
+
+func (c *wgKernelConfigurer) getPeer(ifaceName, peerPubKey string) (wgtypes.Peer, error) {
+	wg, err := wgctrl.New()
+	if err != nil {
+		return wgtypes.Peer{}, err
+	}
+	defer func() {
+		err = wg.Close()
+		if err != nil {
+			log.Errorf("got error while closing wgctl: %v", err)
+		}
+	}()
+
+	wgDevice, err := wg.Device(ifaceName)
+	if err != nil {
+		return wgtypes.Peer{}, err
+	}
+	for _, peer := range wgDevice.Peers {
+		if peer.PublicKey.String() == peerPubKey {
+			return peer, nil
+		}
+	}
+	return wgtypes.Peer{}, fmt.Errorf("peer not found")
+}
+
+func (c *wgKernelConfigurer) configure(config wgtypes.Config) error {
+	wg, err := wgctrl.New()
+	if err != nil {
+		return err
+	}
+	defer wg.Close()
+
+	// validate if device with name exists
+	_, err = wg.Device(c.deviceName)
+	if err != nil {
+		return err
+	}
+	log.Tracef("got Wireguard device %s", c.deviceName)
+
+	return wg.ConfigureDevice(c.deviceName, config)
+}
+
+func (c *wgKernelConfigurer) close() {
+}