418 lines
16 KiB
Go
418 lines
16 KiB
Go
package nebula
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import (
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"sync/atomic"
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"time"
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"github.com/flynn/noise"
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"github.com/golang/protobuf/proto"
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)
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// NOISE IX Handshakes
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// This function constructs a handshake packet, but does not actually send it
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// Sending is done by the handshake manager
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func ixHandshakeStage0(f *Interface, vpnIp uint32, hostinfo *HostInfo) {
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// This queries the lighthouse if we don't know a remote for the host
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// We do it here to provoke the lighthouse to preempt our timer wheel and trigger the stage 1 packet to send
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// more quickly, effect is a quicker handshake.
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if hostinfo.remote == nil {
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f.lightHouse.QueryServer(vpnIp, f)
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}
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err := f.handshakeManager.AddIndexHostInfo(hostinfo)
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(vpnIp)).
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WithField("handshake", m{"stage": 0, "style": "ix_psk0"}).Error("Failed to generate index")
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return
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}
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ci := hostinfo.ConnectionState
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hsProto := &NebulaHandshakeDetails{
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InitiatorIndex: hostinfo.localIndexId,
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Time: uint64(time.Now().Unix()),
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Cert: ci.certState.rawCertificateNoKey,
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}
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hsBytes := []byte{}
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hs := &NebulaHandshake{
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Details: hsProto,
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}
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hsBytes, err = proto.Marshal(hs)
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(vpnIp)).
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WithField("handshake", m{"stage": 0, "style": "ix_psk0"}).Error("Failed to marshal handshake message")
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return
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}
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header := HeaderEncode(make([]byte, HeaderLen), Version, uint8(handshake), handshakeIXPSK0, 0, 1)
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atomic.AddUint64(&ci.atomicMessageCounter, 1)
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msg, _, _, err := ci.H.WriteMessage(header, hsBytes)
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(vpnIp)).
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WithField("handshake", m{"stage": 0, "style": "ix_psk0"}).Error("Failed to call noise.WriteMessage")
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return
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}
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// We are sending handshake packet 1, so we don't expect to receive
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// handshake packet 1 from the responder
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ci.window.Update(f.l, 1)
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hostinfo.HandshakePacket[0] = msg
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hostinfo.HandshakeReady = true
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hostinfo.handshakeStart = time.Now()
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}
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func ixHandshakeStage1(f *Interface, addr *udpAddr, packet []byte, h *Header) {
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ci := f.newConnectionState(f.l, false, noise.HandshakeIX, []byte{}, 0)
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// Mark packet 1 as seen so it doesn't show up as missed
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ci.window.Update(f.l, 1)
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msg, _, _, err := ci.H.ReadMessage(nil, packet[HeaderLen:])
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if err != nil {
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f.l.WithError(err).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Failed to call noise.ReadMessage")
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return
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}
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hs := &NebulaHandshake{}
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err = proto.Unmarshal(msg, hs)
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/*
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l.Debugln("GOT INDEX: ", hs.Details.InitiatorIndex)
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*/
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if err != nil || hs.Details == nil {
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f.l.WithError(err).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Failed unmarshal handshake message")
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return
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}
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remoteCert, err := RecombineCertAndValidate(ci.H, hs.Details.Cert, f.caPool)
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if err != nil {
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f.l.WithError(err).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).WithField("cert", remoteCert).
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Info("Invalid certificate from host")
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return
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}
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vpnIP := ip2int(remoteCert.Details.Ips[0].IP)
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certName := remoteCert.Details.Name
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fingerprint, _ := remoteCert.Sha256Sum()
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if vpnIP == ip2int(f.certState.certificate.Details.Ips[0].IP) {
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Refusing to handshake with myself")
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return
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}
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myIndex, err := generateIndex(f.l)
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Failed to generate index")
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return
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}
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hostinfo := &HostInfo{
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ConnectionState: ci,
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localIndexId: myIndex,
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remoteIndexId: hs.Details.InitiatorIndex,
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hostId: vpnIP,
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HandshakePacket: make(map[uint8][]byte, 0),
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}
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hostinfo.Lock()
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defer hostinfo.Unlock()
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
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Info("Handshake message received")
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hs.Details.ResponderIndex = myIndex
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hs.Details.Cert = ci.certState.rawCertificateNoKey
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hsBytes, err := proto.Marshal(hs)
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Failed to marshal handshake message")
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return
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}
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header := HeaderEncode(make([]byte, HeaderLen), Version, uint8(handshake), handshakeIXPSK0, hs.Details.InitiatorIndex, 2)
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msg, dKey, eKey, err := ci.H.WriteMessage(header, hsBytes)
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Failed to call noise.WriteMessage")
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return
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} else if dKey == nil || eKey == nil {
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f.l.WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Noise did not arrive at a key")
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return
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}
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hostinfo.HandshakePacket[0] = make([]byte, len(packet[HeaderLen:]))
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copy(hostinfo.HandshakePacket[0], packet[HeaderLen:])
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// Regardless of whether you are the sender or receiver, you should arrive here
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// and complete standing up the connection.
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hostinfo.HandshakePacket[2] = make([]byte, len(msg))
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copy(hostinfo.HandshakePacket[2], msg)
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// We are sending handshake packet 2, so we don't expect to receive
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// handshake packet 2 from the initiator.
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ci.window.Update(f.l, 2)
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ci.peerCert = remoteCert
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ci.dKey = NewNebulaCipherState(dKey)
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ci.eKey = NewNebulaCipherState(eKey)
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hostinfo.remotes = f.lightHouse.QueryCache(vpnIP)
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hostinfo.SetRemote(addr)
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hostinfo.CreateRemoteCIDR(remoteCert)
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// Only overwrite existing record if we should win the handshake race
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overwrite := vpnIP > ip2int(f.certState.certificate.Details.Ips[0].IP)
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existing, err := f.handshakeManager.CheckAndComplete(hostinfo, 0, overwrite, f)
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if err != nil {
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switch err {
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case ErrAlreadySeen:
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msg = existing.HandshakePacket[2]
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f.messageMetrics.Tx(handshake, NebulaMessageSubType(msg[1]), 1)
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err := f.outside.WriteTo(msg, addr)
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if err != nil {
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f.l.WithField("vpnIp", IntIp(existing.hostId)).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).WithField("cached", true).
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WithError(err).Error("Failed to send handshake message")
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} else {
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f.l.WithField("vpnIp", IntIp(existing.hostId)).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).WithField("cached", true).
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Info("Handshake message sent")
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}
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return
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case ErrExistingHostInfo:
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// This means there was an existing tunnel and we didn't win
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// handshake avoidance
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//TODO: sprinkle the new protobuf stuff in here, send a reply to get the recv_errors flowing
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//TODO: if not new send a test packet like old
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
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Info("Prevented a handshake race")
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// Send a test packet to trigger an authenticated tunnel test, this should suss out any lingering tunnel issues
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f.SendMessageToVpnIp(test, testRequest, vpnIP, []byte(""), make([]byte, 12, 12), make([]byte, mtu))
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return
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case ErrLocalIndexCollision:
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// This means we failed to insert because of collision on localIndexId. Just let the next handshake packet retry
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
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WithField("localIndex", hostinfo.localIndexId).WithField("collision", IntIp(existing.hostId)).
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Error("Failed to add HostInfo due to localIndex collision")
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return
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case ErrExistingHandshake:
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// We have a race where both parties think they are an initiator and this tunnel lost, let the other one finish
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
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Error("Prevented a pending handshake race")
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return
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default:
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// Shouldn't happen, but just in case someone adds a new error type to CheckAndComplete
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// And we forget to update it here
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f.l.WithError(err).WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
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Error("Failed to add HostInfo to HostMap")
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return
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}
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}
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// Do the send
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f.messageMetrics.Tx(handshake, NebulaMessageSubType(msg[1]), 1)
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err = f.outside.WriteTo(msg, addr)
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if err != nil {
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
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WithError(err).Error("Failed to send handshake")
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} else {
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
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Info("Handshake message sent")
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}
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hostinfo.handshakeComplete(f.l)
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return
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}
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func ixHandshakeStage2(f *Interface, addr *udpAddr, hostinfo *HostInfo, packet []byte, h *Header) bool {
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if hostinfo == nil {
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// Nothing here to tear down, got a bogus stage 2 packet
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return true
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}
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hostinfo.Lock()
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defer hostinfo.Unlock()
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ci := hostinfo.ConnectionState
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if ci.ready {
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f.l.WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).WithField("header", h).
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Info("Handshake is already complete")
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//TODO: evaluate addr for preference, if we handshook with a less preferred addr we can correct quickly here
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// We already have a complete tunnel, there is nothing that can be done by processing further stage 1 packets
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return false
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}
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msg, eKey, dKey, err := ci.H.ReadMessage(nil, packet[HeaderLen:])
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).WithField("header", h).
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Error("Failed to call noise.ReadMessage")
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// We don't want to tear down the connection on a bad ReadMessage because it could be an attacker trying
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// to DOS us. Every other error condition after should to allow a possible good handshake to complete in the
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// near future
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return false
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} else if dKey == nil || eKey == nil {
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f.l.WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
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Error("Noise did not arrive at a key")
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// This should be impossible in IX but just in case, if we get here then there is no chance to recover
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// the handshake state machine. Tear it down
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return true
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}
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hs := &NebulaHandshake{}
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err = proto.Unmarshal(msg, hs)
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if err != nil || hs.Details == nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).Error("Failed unmarshal handshake message")
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// The handshake state machine is complete, if things break now there is no chance to recover. Tear down and start again
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return true
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}
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remoteCert, err := RecombineCertAndValidate(ci.H, hs.Details.Cert, f.caPool)
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if err != nil {
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f.l.WithError(err).WithField("vpnIp", IntIp(hostinfo.hostId)).WithField("udpAddr", addr).
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WithField("cert", remoteCert).WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
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Error("Invalid certificate from host")
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// The handshake state machine is complete, if things break now there is no chance to recover. Tear down and start again
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return true
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}
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vpnIP := ip2int(remoteCert.Details.Ips[0].IP)
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certName := remoteCert.Details.Name
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fingerprint, _ := remoteCert.Sha256Sum()
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// Ensure the right host responded
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if vpnIP != hostinfo.hostId {
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f.l.WithField("intendedVpnIp", IntIp(hostinfo.hostId)).WithField("haveVpnIp", IntIp(vpnIP)).
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WithField("udpAddr", addr).WithField("certName", certName).
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WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
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Info("Incorrect host responded to handshake")
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// Release our old handshake from pending, it should not continue
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f.handshakeManager.pendingHostMap.DeleteHostInfo(hostinfo)
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// Create a new hostinfo/handshake for the intended vpn ip
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//TODO: this adds it to the timer wheel in a way that aggressively retries
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newHostInfo := f.getOrHandshake(hostinfo.hostId)
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newHostInfo.Lock()
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// Block the current used address
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newHostInfo.remotes = hostinfo.remotes
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newHostInfo.remotes.BlockRemote(addr)
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// Get the correct remote list for the host we did handshake with
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hostinfo.remotes = f.lightHouse.QueryCache(vpnIP)
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f.l.WithField("blockedUdpAddrs", newHostInfo.remotes.CopyBlockedRemotes()).WithField("vpnIp", IntIp(vpnIP)).
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WithField("remotes", newHostInfo.remotes.CopyAddrs(f.hostMap.preferredRanges)).
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Info("Blocked addresses for handshakes")
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// Swap the packet store to benefit the original intended recipient
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hostinfo.ConnectionState.queueLock.Lock()
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newHostInfo.packetStore = hostinfo.packetStore
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hostinfo.packetStore = []*cachedPacket{}
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hostinfo.ConnectionState.queueLock.Unlock()
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// Finally, put the correct vpn ip in the host info, tell them to close the tunnel, and return true to tear down
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hostinfo.hostId = vpnIP
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f.sendCloseTunnel(hostinfo)
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newHostInfo.Unlock()
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return true
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}
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// Mark packet 2 as seen so it doesn't show up as missed
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ci.window.Update(f.l, 2)
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duration := time.Since(hostinfo.handshakeStart).Nanoseconds()
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f.l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", addr).
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WithField("certName", certName).
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WithField("fingerprint", fingerprint).
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WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
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WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
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WithField("durationNs", duration).
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Info("Handshake message received")
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hostinfo.remoteIndexId = hs.Details.ResponderIndex
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hs.Details.Cert = ci.certState.rawCertificateNoKey
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// Store their cert and our symmetric keys
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ci.peerCert = remoteCert
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ci.dKey = NewNebulaCipherState(dKey)
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ci.eKey = NewNebulaCipherState(eKey)
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// Make sure the current udpAddr being used is set for responding
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hostinfo.SetRemote(addr)
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// Build up the radix for the firewall if we have subnets in the cert
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hostinfo.CreateRemoteCIDR(remoteCert)
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// Complete our handshake and update metrics, this will replace any existing tunnels for this vpnIp
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//TODO: Complete here does not do a race avoidance, it will just take the new tunnel. Is this ok?
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f.handshakeManager.Complete(hostinfo, f)
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hostinfo.handshakeComplete(f.l)
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f.metricHandshakes.Update(duration)
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return false
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}
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