test and stupid fix

* Bump actions/setup-go from 5 to 6

Bumps [actions/setup-go](https://github.com/actions/setup-go) from 5 to 6.
- [Release notes](https://github.com/actions/setup-go/releases)
- [Commits](https://github.com/actions/setup-go/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-go
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* Hardcode the last one to go v1.25

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Nate Brown <nbrown.us@gmail.com>

.github/workflows/gofmt.yml

@@ -16,9 +16,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Install goimports

.github/workflows/release.yml

@@ -12,9 +12,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Build
@@ -35,9 +35,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Build
@@ -68,9 +68,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Import certificates

.github/workflows/smoke-extra.yml

@@ -22,9 +22,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version-file: 'go.mod'
+        go-version: '1.25'
         check-latest: true
 
     - name: add hashicorp source

.github/workflows/smoke.yml

@@ -20,9 +20,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: build

.github/workflows/test.yml

@@ -20,9 +20,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -34,7 +34,7 @@ jobs:
     - name: golangci-lint
       uses: golangci/golangci-lint-action@v8
       with:
-        version: v2.1
+        version: v2.5
 
     - name: Test
       run: make test
@@ -58,9 +58,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -79,9 +79,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.22'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -100,9 +100,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build nebula
@@ -117,7 +117,7 @@ jobs:
     - name: golangci-lint
       uses: golangci/golangci-lint-action@v8
       with:
-        version: v2.1
+        version: v2.5
 
     - name: Test
       run: make test

cert/cert_v1.go

@@ -110,8 +110,10 @@ func (c *certificateV1) CheckSignature(key []byte) bool {
 	case Curve_CURVE25519:
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
-		x, y := elliptic.Unmarshal(elliptic.P256(), key)
+		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)
-		pubKey := &ecdsa.PublicKey{Curve: elliptic.P256(), X: x, Y: y}
+		if err != nil {
+			return false
+		}
 		hashed := sha256.Sum256(b)
 		return ecdsa.VerifyASN1(pubKey, hashed[:], c.signature)
 	default:

cert/cert_v2.go

@@ -149,8 +149,10 @@ func (c *certificateV2) CheckSignature(key []byte) bool {
 	case Curve_CURVE25519:
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
-		x, y := elliptic.Unmarshal(elliptic.P256(), key)
+		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)
-		pubKey := &ecdsa.PublicKey{Curve: elliptic.P256(), X: x, Y: y}
+		if err != nil {
+			return false
+		}
 		hashed := sha256.Sum256(b)
 		return ecdsa.VerifyASN1(pubKey, hashed[:], c.signature)
 	default:

cert/sign.go

@@ -7,7 +7,6 @@ import (
 	"crypto/rand"
 	"crypto/sha256"
 	"fmt"
-	"math/big"
 	"net/netip"
 	"time"
 )
@@ -55,15 +54,10 @@ func (t *TBSCertificate) Sign(signer Certificate, curve Curve, key []byte) (Cert
 		}
 		return t.SignWith(signer, curve, sp)
 	case Curve_P256:
-		pk := &ecdsa.PrivateKey{
+		pk, err := ecdsa.ParseRawPrivateKey(elliptic.P256(), key)
-			PublicKey: ecdsa.PublicKey{
+		if err != nil {
-				Curve: elliptic.P256(),
+			return nil, err
-			},
-			// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L95
-			D: new(big.Int).SetBytes(key),
 		}
-		// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L119
-		pk.X, pk.Y = pk.Curve.ScalarBaseMult(key)
 		sp := func(certBytes []byte) ([]byte, error) {
 			// We need to hash first for ECDSA
 			// - https://pkg.go.dev/crypto/ecdsa#SignASN1

cert_test/cert.go

@@ -114,6 +114,33 @@ func NewTestCert(v cert.Version, curve cert.Curve, ca cert.Certificate, key []by
 	return c, pub, cert.MarshalPrivateKeyToPEM(curve, priv), pem
 }
 
+func NewTestCertDifferentVersion(c cert.Certificate, v cert.Version, ca cert.Certificate, key []byte) (cert.Certificate, []byte) {
+	nc := &cert.TBSCertificate{
+		Version:        v,
+		Curve:          c.Curve(),
+		Name:           c.Name(),
+		Networks:       c.Networks(),
+		UnsafeNetworks: c.UnsafeNetworks(),
+		Groups:         c.Groups(),
+		NotBefore:      time.Unix(c.NotBefore().Unix(), 0),
+		NotAfter:       time.Unix(c.NotAfter().Unix(), 0),
+		PublicKey:      c.PublicKey(),
+		IsCA:           false,
+	}
+
+	c, err := nc.Sign(ca, ca.Curve(), key)
+	if err != nil {
+		panic(err)
+	}
+
+	pem, err := c.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+
+	return c, pem
+}
+
 func X25519Keypair() ([]byte, []byte) {
 	privkey := make([]byte, 32)
 	if _, err := io.ReadFull(rand.Reader, privkey); err != nil {

connection_manager.go

@@ -354,7 +354,6 @@ func (cm *connectionManager) makeTrafficDecision(localIndex uint32, now time.Tim
 
 		if mainHostInfo {
 			decision = tryRehandshake
-
 		} else {
 			if cm.shouldSwapPrimary(hostinfo) {
 				decision = swapPrimary
@@ -461,6 +460,10 @@ func (cm *connectionManager) shouldSwapPrimary(current *HostInfo) bool {
 	}
 
 	crt := cm.intf.pki.getCertState().getCertificate(current.ConnectionState.myCert.Version())
+	if crt == nil {
+		//my cert was reloaded away. We should definitely swap from this tunnel
+		return true
+	}
 	// If this tunnel is using the latest certificate then we should swap it to primary for a bit and see if things
 	// settle down.
 	return bytes.Equal(current.ConnectionState.myCert.Signature(), crt.Signature())
@@ -475,31 +478,34 @@ func (cm *connectionManager) swapPrimary(current, primary *HostInfo) {
 	cm.hostMap.Unlock()
 }
 
-// isInvalidCertificate will check if we should destroy a tunnel if pki.disconnect_invalid is true and
+// isInvalidCertificate decides if we should destroy a tunnel.
-// the certificate is no longer valid. Block listed certificates will skip the pki.disconnect_invalid
+// returns true if pki.disconnect_invalid is true and the certificate is no longer valid.
-// check and return true.
+// Blocklisted certificates will skip the pki.disconnect_invalid check and return true.
 func (cm *connectionManager) isInvalidCertificate(now time.Time, hostinfo *HostInfo) bool {
 	remoteCert := hostinfo.GetCert()
 	if remoteCert == nil {
-		return false
+		return false //don't tear down tunnels for handshakes in progress
 	}
 
 	caPool := cm.intf.pki.GetCAPool()
 	err := caPool.VerifyCachedCertificate(now, remoteCert)
 	if err == nil {
-		return false
+		return false //cert is still valid! yay!
-	}
+	} else if err == cert.ErrBlockListed { //avoiding errors.Is for speed
-
-	if !cm.intf.disconnectInvalid.Load() && err != cert.ErrBlockListed {
 		// Block listed certificates should always be disconnected
+		hostinfo.logger(cm.l).WithError(err).
+			WithField("fingerprint", remoteCert.Fingerprint).
+			Info("Remote certificate is blocked, tearing down the tunnel")
+		return true
+	} else if cm.intf.disconnectInvalid.Load() {
+		hostinfo.logger(cm.l).WithError(err).
+			WithField("fingerprint", remoteCert.Fingerprint).
+			Info("Remote certificate is no longer valid, tearing down the tunnel")
+		return true
+	} else {
+		//if we reach here, the cert is no longer valid, but we're configured to keep tunnels from now-invalid certs open
 		return false
 	}
-
-	hostinfo.logger(cm.l).WithError(err).
-		WithField("fingerprint", remoteCert.Fingerprint).
-		Info("Remote certificate is no longer valid, tearing down the tunnel")
-
-	return true
 }
 
 func (cm *connectionManager) sendPunch(hostinfo *HostInfo) {
@@ -530,15 +536,45 @@ func (cm *connectionManager) sendPunch(hostinfo *HostInfo) {
 func (cm *connectionManager) tryRehandshake(hostinfo *HostInfo) {
 	cs := cm.intf.pki.getCertState()
 	curCrt := hostinfo.ConnectionState.myCert
-	myCrt := cs.getCertificate(curCrt.Version())
+	curCrtVersion := curCrt.Version()
-	if curCrt.Version() >= cs.initiatingVersion && bytes.Equal(curCrt.Signature(), myCrt.Signature()) == true {
+	myCrt := cs.getCertificate(curCrtVersion)
-		// The current tunnel is using the latest certificate and version, no need to rehandshake.
+	if myCrt == nil {
+		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+			WithField("version", curCrtVersion).
+			WithField("reason", "local certificate removed").
+			Info("Re-handshaking with remote")
+		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
 		return
 	}
+	peerCrt := hostinfo.ConnectionState.peerCert
+	if peerCrt != nil && curCrtVersion < peerCrt.Certificate.Version() {
+		// if our certificate version is less than theirs, and we have a matching version available, rehandshake?
+		if cs.getCertificate(peerCrt.Certificate.Version()) != nil {
+			cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+				WithField("version", curCrtVersion).
+				WithField("peerVersion", peerCrt.Certificate.Version()).
+				WithField("reason", "local certificate version lower than peer, attempting to correct").
+				Info("Re-handshaking with remote")
+			cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], func(hh *HandshakeHostInfo) {
+				hh.initiatingVersionOverride = peerCrt.Certificate.Version()
+			})
+			return
+		}
+	}
+	if !bytes.Equal(curCrt.Signature(), myCrt.Signature()) {
+		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+			WithField("reason", "local certificate is not current").
+			Info("Re-handshaking with remote")
 
-	cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
-		WithField("reason", "local certificate is not current").
+		return
-		Info("Re-handshaking with remote")
+	}
+	if curCrtVersion < cs.initiatingVersion {
+		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+			WithField("reason", "current cert version < pki.initiatingVersion").
+			Info("Re-handshaking with remote")
 
-	cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+		return
+	}
 }

connection_manager_test.go

@@ -22,7 +22,7 @@ func newTestLighthouse() *LightHouse {
 		addrMap:   map[netip.Addr]*RemoteList{},
 		queryChan: make(chan netip.Addr, 10),
 	}
-	lighthouses := map[netip.Addr]struct{}{}
+	lighthouses := []netip.Addr{}
 	staticList := map[netip.Addr]struct{}{}
 
 	lh.lighthouses.Store(&lighthouses)

e2e/helpers_test.go

@@ -29,8 +29,6 @@ type m = map[string]any
 
 // newSimpleServer creates a nebula instance with many assumptions
 func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name string, sVpnNetworks string, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
-	l := NewTestLogger()
-
 	var vpnNetworks []netip.Prefix
 	for _, sn := range strings.Split(sVpnNetworks, ",") {
 		vpnIpNet, err := netip.ParsePrefix(strings.TrimSpace(sn))
@@ -56,6 +54,25 @@ func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name
 		budpIp[3] = 239
 		udpAddr = netip.AddrPortFrom(netip.AddrFrom16(budpIp), 4242)
 	}
+	return newSimpleServerWithUdp(v, caCrt, caKey, name, sVpnNetworks, udpAddr, overrides)
+}
+
+func newSimpleServerWithUdp(v cert.Version, caCrt cert.Certificate, caKey []byte, name string, sVpnNetworks string, udpAddr netip.AddrPort, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
+	l := NewTestLogger()
+
+	var vpnNetworks []netip.Prefix
+	for _, sn := range strings.Split(sVpnNetworks, ",") {
+		vpnIpNet, err := netip.ParsePrefix(strings.TrimSpace(sn))
+		if err != nil {
+			panic(err)
+		}
+		vpnNetworks = append(vpnNetworks, vpnIpNet)
+	}
+
+	if len(vpnNetworks) == 0 {
+		panic("no vpn networks")
+	}
+
 	_, _, myPrivKey, myPEM := cert_test.NewTestCert(v, cert.Curve_CURVE25519, caCrt, caKey, name, time.Now(), time.Now().Add(5*time.Minute), vpnNetworks, nil, []string{})
 
 	caB, err := caCrt.MarshalPEM()
@@ -129,6 +146,109 @@ func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name
 	return control, vpnNetworks, udpAddr, c
 }
 
+// newServer creates a nebula instance with fewer assumptions
+func newServer(caCrt []cert.Certificate, certs []cert.Certificate, key []byte, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
+	l := NewTestLogger()
+
+	vpnNetworks := certs[len(certs)-1].Networks()
+
+	var udpAddr netip.AddrPort
+	if vpnNetworks[0].Addr().Is4() {
+		budpIp := vpnNetworks[0].Addr().As4()
+		budpIp[1] -= 128
+		udpAddr = netip.AddrPortFrom(netip.AddrFrom4(budpIp), 4242)
+	} else {
+		budpIp := vpnNetworks[0].Addr().As16()
+		// beef for funsies
+		budpIp[2] = 190
+		budpIp[3] = 239
+		udpAddr = netip.AddrPortFrom(netip.AddrFrom16(budpIp), 4242)
+	}
+
+	caStr := ""
+	for _, ca := range caCrt {
+		x, err := ca.MarshalPEM()
+		if err != nil {
+			panic(err)
+		}
+		caStr += string(x)
+	}
+	certStr := ""
+	for _, c := range certs {
+		x, err := c.MarshalPEM()
+		if err != nil {
+			panic(err)
+		}
+		certStr += string(x)
+	}
+
+	mc := m{
+		"pki": m{
+			"ca":   caStr,
+			"cert": certStr,
+			"key":  string(key),
+		},
+		//"tun": m{"disabled": true},
+		"firewall": m{
+			"outbound": []m{{
+				"proto": "any",
+				"port":  "any",
+				"host":  "any",
+			}},
+			"inbound": []m{{
+				"proto": "any",
+				"port":  "any",
+				"host":  "any",
+			}},
+		},
+		//"handshakes": m{
+		//	"try_interval": "1s",
+		//},
+		"listen": m{
+			"host": udpAddr.Addr().String(),
+			"port": udpAddr.Port(),
+		},
+		"logging": m{
+			"timestamp_format": fmt.Sprintf("%v 15:04:05.000000", certs[0].Name()),
+			"level":            l.Level.String(),
+		},
+		"timers": m{
+			"pending_deletion_interval": 2,
+			"connection_alive_interval": 2,
+		},
+	}
+
+	if overrides != nil {
+		final := m{}
+		err := mergo.Merge(&final, overrides, mergo.WithAppendSlice)
+		if err != nil {
+			panic(err)
+		}
+		err = mergo.Merge(&final, mc, mergo.WithAppendSlice)
+		if err != nil {
+			panic(err)
+		}
+		mc = final
+	}
+
+	cb, err := yaml.Marshal(mc)
+	if err != nil {
+		panic(err)
+	}
+
+	c := config.NewC(l)
+	cStr := string(cb)
+	c.LoadString(cStr)
+
+	control, err := nebula.Main(c, false, "e2e-test", l, nil)
+
+	if err != nil {
+		panic(err)
+	}
+
+	return control, vpnNetworks, udpAddr, c
+}
+
 type doneCb func()
 
 func deadline(t *testing.T, seconds time.Duration) doneCb {

e2e/tunnels_test.go

@@ -4,12 +4,16 @@
 package e2e
 
 import (
+	"fmt"
+	"net/netip"
 	"testing"
 	"time"
 
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/cert_test"
 	"github.com/slackhq/nebula/e2e/router"
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v3"
 )
 
 func TestDropInactiveTunnels(t *testing.T) {
@@ -55,3 +59,309 @@ func TestDropInactiveTunnels(t *testing.T) {
 	myControl.Stop()
 	theirControl.Stop()
 }
+
+func TestCertUpgrade(t *testing.T) {
+	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
+	// under ideal conditions
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	caB, err := ca.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	ca2B, err := ca2.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	caStr := fmt.Sprintf("%s\n%s", caB, ca2B)
+
+	myCert, _, myPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
+	_, myCert2Pem := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
+
+	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
+	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
+
+	myControl, myVpnIpNet, myUdpAddr, myC := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert}, myPrivKey, m{})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+	defer r.RenderFlow()
+
+	r.Log("Assert the tunnel between me and them works")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	r.Log("yay")
+	//todo ???
+	time.Sleep(1 * time.Second)
+	r.FlushAll()
+
+	mc := m{
+		"pki": m{
+			"ca":   caStr,
+			"cert": string(myCert2Pem),
+			"key":  string(myPrivKey),
+		},
+		//"tun": m{"disabled": true},
+		"firewall": myC.Settings["firewall"],
+		//"handshakes": m{
+		//	"try_interval": "1s",
+		//},
+		"listen":  myC.Settings["listen"],
+		"logging": myC.Settings["logging"],
+		"timers":  myC.Settings["timers"],
+	}
+
+	cb, err := yaml.Marshal(mc)
+	if err != nil {
+		panic(err)
+	}
+
+	r.Logf("reload new v2-only config")
+	err = myC.ReloadConfigString(string(cb))
+	assert.NoError(t, err)
+	r.Log("yay, spin until their sees it")
+	waitStart := time.Now()
+	for {
+		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+		if c == nil {
+			r.Log("nil")
+		} else {
+			version := c.Cert.Version()
+			r.Logf("version %d", version)
+			if version == cert.Version2 {
+				break
+			}
+		}
+		since := time.Since(waitStart)
+		if since > time.Second*10 {
+			t.Fatal("Cert should be new by now")
+		}
+		time.Sleep(time.Second)
+	}
+
+	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
+
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestCertDowngrade(t *testing.T) {
+	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
+	// under ideal conditions
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	caB, err := ca.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	ca2B, err := ca2.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	caStr := fmt.Sprintf("%s\n%s", caB, ca2B)
+
+	myCert, _, myPrivKey, myCertPem := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
+	myCert2, _ := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
+
+	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
+	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
+
+	myControl, myVpnIpNet, myUdpAddr, myC := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert2}, myPrivKey, m{})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+	defer r.RenderFlow()
+
+	r.Log("Assert the tunnel between me and them works")
+	//assertTunnel(t, theirVpnIpNet[0].Addr(), myVpnIpNet[0].Addr(), theirControl, myControl, r)
+	//r.Log("yay")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	r.Log("yay")
+	//todo ???
+	time.Sleep(1 * time.Second)
+	r.FlushAll()
+
+	mc := m{
+		"pki": m{
+			"ca":   caStr,
+			"cert": string(myCertPem),
+			"key":  string(myPrivKey),
+		},
+		"firewall": myC.Settings["firewall"],
+		"listen":   myC.Settings["listen"],
+		"logging":  myC.Settings["logging"],
+		"timers":   myC.Settings["timers"],
+	}
+
+	cb, err := yaml.Marshal(mc)
+	if err != nil {
+		panic(err)
+	}
+
+	r.Logf("reload new v1-only config")
+	err = myC.ReloadConfigString(string(cb))
+	assert.NoError(t, err)
+	r.Log("yay, spin until their sees it")
+	waitStart := time.Now()
+	for {
+		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+		c2 := myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
+		if c == nil || c2 == nil {
+			r.Log("nil")
+		} else {
+			version := c.Cert.Version()
+			theirVersion := c2.Cert.Version()
+			r.Logf("version %d,%d", version, theirVersion)
+			if version == cert.Version1 {
+				break
+			}
+		}
+		since := time.Since(waitStart)
+		if since > time.Second*5 {
+			r.Log("wtf")
+		}
+		if since > time.Second*10 {
+			r.Log("wtf")
+			t.Fatal("Cert should be new by now")
+		}
+		time.Sleep(time.Second)
+	}
+
+	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
+
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestCertMismatchCorrection(t *testing.T) {
+	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
+	// under ideal conditions
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	myCert, _, myPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
+	myCert2, _ := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
+
+	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
+	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
+
+	myControl, myVpnIpNet, myUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert2}, myPrivKey, m{})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+	defer r.RenderFlow()
+
+	r.Log("Assert the tunnel between me and them works")
+	//assertTunnel(t, theirVpnIpNet[0].Addr(), myVpnIpNet[0].Addr(), theirControl, myControl, r)
+	//r.Log("yay")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	r.Log("yay")
+	//todo ???
+	time.Sleep(1 * time.Second)
+	r.FlushAll()
+
+	waitStart := time.Now()
+	for {
+		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+		c2 := myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
+		if c == nil || c2 == nil {
+			r.Log("nil")
+		} else {
+			version := c.Cert.Version()
+			theirVersion := c2.Cert.Version()
+			r.Logf("version %d,%d", version, theirVersion)
+			if version == theirVersion {
+				break
+			}
+		}
+		since := time.Since(waitStart)
+		if since > time.Second*5 {
+			r.Log("wtf")
+		}
+		if since > time.Second*10 {
+			r.Log("wtf")
+			t.Fatal("Cert should be new by now")
+		}
+		time.Sleep(time.Second)
+	}
+
+	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
+
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestCrossStackRelaysWork(t *testing.T) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version2, ca, caKey, "me     ", "10.128.0.1/24,fc00::1/64", m{"relay": m{"use_relays": true}})
+	relayControl, relayVpnIpNet, relayUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "relay  ", "10.128.0.128/24,fc00::128/64", m{"relay": m{"am_relay": true}})
+	theirUdp := netip.MustParseAddrPort("10.0.0.2:4242")
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServerWithUdp(cert.Version2, ca, caKey, "them   ", "fc00::2/64", theirUdp, m{"relay": m{"use_relays": true}})
+
+	//myVpnV4 := myVpnIpNet[0]
+	myVpnV6 := myVpnIpNet[1]
+	relayVpnV4 := relayVpnIpNet[0]
+	relayVpnV6 := relayVpnIpNet[1]
+	theirVpnV6 := theirVpnIpNet[0]
+
+	// Teach my how to get to the relay and that their can be reached via the relay
+	myControl.InjectLightHouseAddr(relayVpnV4.Addr(), relayUdpAddr)
+	myControl.InjectLightHouseAddr(relayVpnV6.Addr(), relayUdpAddr)
+	myControl.InjectRelays(theirVpnV6.Addr(), []netip.Addr{relayVpnV6.Addr()})
+	relayControl.InjectLightHouseAddr(theirVpnV6.Addr(), theirUdpAddr)
+
+	// Build a router so we don't have to reason who gets which packet
+	r := router.NewR(t, myControl, relayControl, theirControl)
+	defer r.RenderFlow()
+
+	// Start the servers
+	myControl.Start()
+	relayControl.Start()
+	theirControl.Start()
+
+	t.Log("Trigger a handshake from me to them via the relay")
+	myControl.InjectTunUDPPacket(theirVpnV6.Addr(), 80, myVpnV6.Addr(), 80, []byte("Hi from me"))
+
+	p := r.RouteForAllUntilTxTun(theirControl)
+	r.Log("Assert the tunnel works")
+	assertUdpPacket(t, []byte("Hi from me"), p, myVpnV6.Addr(), theirVpnV6.Addr(), 80, 80)
+
+	t.Log("reply?")
+	theirControl.InjectTunUDPPacket(myVpnV6.Addr(), 80, theirVpnV6.Addr(), 80, []byte("Hi from them"))
+	p = r.RouteForAllUntilTxTun(myControl)
+	assertUdpPacket(t, []byte("Hi from them"), p, theirVpnV6.Addr(), myVpnV6.Addr(), 80, 80)
+
+	r.RenderHostmaps("Final hostmaps", myControl, relayControl, theirControl)
+	//t.Log("finish up")
+	//myControl.Stop()
+	//theirControl.Stop()
+	//relayControl.Stop()
+}

go.mod

@@ -1,8 +1,6 @@
 module github.com/slackhq/nebula
 
-go 1.23.0
+go 1.25
-
-toolchain go1.24.1
 
 require (
 	dario.cat/mergo v1.0.2

handshake_ix.go

@@ -23,13 +23,17 @@ func ixHandshakeStage0(f *Interface, hh *HandshakeHostInfo) bool {
 		return false
 	}
 
-	// If we're connecting to a v6 address we must use a v2 cert
 	cs := f.pki.getCertState()
 	v := cs.initiatingVersion
-	for _, a := range hh.hostinfo.vpnAddrs {
+	if hh.initiatingVersionOverride != cert.VersionPre1 {
-		if a.Is6() {
+		v = hh.initiatingVersionOverride
-			v = cert.Version2
+	} else if v < cert.Version2 {
-			break
+		// If we're connecting to a v6 address we must use a v2 cert
+		for _, a := range hh.hostinfo.vpnAddrs {
+			if a.Is6() {
+				v = cert.Version2
+				break
+			}
 		}
 	}
 
@@ -163,16 +167,19 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	if remoteCert.Certificate.Version() != ci.myCert.Version() {
 		// We started off using the wrong certificate version, lets see if we can match the version that was sent to us
-		rc := cs.getCertificate(remoteCert.Certificate.Version())
+		myCertOtherVersion := cs.getCertificate(remoteCert.Certificate.Version())
-		if rc == nil {
+		if myCertOtherVersion == nil {
-			f.l.WithError(err).WithField("udpAddr", addr).
+			if f.l.Level >= logrus.DebugLevel {
-				WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).WithField("cert", remoteCert).
+				f.l.WithError(err).WithFields(m{
-				Info("Unable to handshake with host due to missing certificate version")
+					"udpAddr":   addr,
-			return
+					"handshake": m{"stage": 1, "style": "ix_psk0"},
+					"cert":      remoteCert,
+				}).Debug("Might be unable to handshake with host due to missing certificate version")
+			}
+		} else {
+			// Record the certificate we are actually using
+			ci.myCert = myCertOtherVersion
 		}
-
-		// Record the certificate we are actually using
-		ci.myCert = rc
 	}
 
 	if len(remoteCert.Certificate.Networks()) == 0 {
@@ -459,7 +466,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	f.connectionManager.AddTrafficWatch(hostinfo)
 
-	hostinfo.remotes.ResetBlockedRemotes()
+	hostinfo.remotes.RefreshFromHandshake(vpnAddrs)
 
 	return
 }
@@ -667,7 +674,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 		f.cachedPacketMetrics.sent.Inc(int64(len(hh.packetStore)))
 	}
 
-	hostinfo.remotes.ResetBlockedRemotes()
+	hostinfo.remotes.RefreshFromHandshake(vpnAddrs)
 	f.metricHandshakes.Update(duration)
 
 	return false

handshake_manager.go

@@ -68,11 +68,12 @@ type HandshakeManager struct {
 type HandshakeHostInfo struct {
 	sync.Mutex
 
-	startTime   time.Time        // Time that we first started trying with this handshake
+	startTime                 time.Time        // Time that we first started trying with this handshake
-	ready       bool             // Is the handshake ready
+	ready                     bool             // Is the handshake ready
-	counter     int64            // How many attempts have we made so far
+	initiatingVersionOverride cert.Version     // Should we use a non-default cert version for this handshake?
-	lastRemotes []netip.AddrPort // Remotes that we sent to during the previous attempt
+	counter                   int64            // How many attempts have we made so far
-	packetStore []*cachedPacket  // A set of packets to be transmitted once the handshake completes
+	lastRemotes               []netip.AddrPort // Remotes that we sent to during the previous attempt
+	packetStore               []*cachedPacket  // A set of packets to be transmitted once the handshake completes
 
 	hostinfo *HostInfo
 }
@@ -299,6 +300,8 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 						InitiatorRelayIndex: idx,
 					}
 
+					relayFrom := hm.f.myVpnAddrs[0]
+
 					switch relayHostInfo.GetCert().Certificate.Version() {
 					case cert.Version1:
 						if !hm.f.myVpnAddrs[0].Is4() {
@@ -316,7 +319,13 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 						b = vpnIp.As4()
 						m.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 					case cert.Version2:
-						m.RelayFromAddr = netAddrToProtoAddr(hm.f.myVpnAddrs[0])
+						if vpnIp.Is4() {
+							relayFrom = hm.f.myVpnAddrs[0]
+						} else {
+							//todo do this smarter
+							relayFrom = hm.f.myVpnAddrs[len(hm.f.myVpnAddrs)-1]
+						}
+						m.RelayFromAddr = netAddrToProtoAddr(relayFrom)
 						m.RelayToAddr = netAddrToProtoAddr(vpnIp)
 					default:
 						hostinfo.logger(hm.l).Error("Unknown certificate version found while creating relay")
@@ -331,7 +340,7 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 					} else {
 						hm.f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, make([]byte, 12), make([]byte, mtu))
 						hm.l.WithFields(logrus.Fields{
-							"relayFrom":           hm.f.myVpnAddrs[0],
+							"relayFrom":           relayFrom,
 							"relayTo":             vpnIp,
 							"initiatorRelayIndex": idx,
 							"relay":               relay}).
@@ -357,6 +366,8 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 					InitiatorRelayIndex: existingRelay.LocalIndex,
 				}
 
+				relayFrom := hm.f.myVpnAddrs[0]
+
 				switch relayHostInfo.GetCert().Certificate.Version() {
 				case cert.Version1:
 					if !hm.f.myVpnAddrs[0].Is4() {
@@ -374,7 +385,14 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 					b = vpnIp.As4()
 					m.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 				case cert.Version2:
-					m.RelayFromAddr = netAddrToProtoAddr(hm.f.myVpnAddrs[0])
+					if vpnIp.Is4() {
+						relayFrom = hm.f.myVpnAddrs[0]
+					} else {
+						//todo do this smarter
+						relayFrom = hm.f.myVpnAddrs[len(hm.f.myVpnAddrs)-1]
+					}
+
+					m.RelayFromAddr = netAddrToProtoAddr(relayFrom)
 					m.RelayToAddr = netAddrToProtoAddr(vpnIp)
 				default:
 					hostinfo.logger(hm.l).Error("Unknown certificate version found while creating relay")
@@ -389,7 +407,7 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 					// This must send over the hostinfo, not over hm.Hosts[ip]
 					hm.f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, make([]byte, 12), make([]byte, mtu))
 					hm.l.WithFields(logrus.Fields{
-						"relayFrom":           hm.f.myVpnAddrs[0],
+						"relayFrom":           relayFrom,
 						"relayTo":             vpnIp,
 						"initiatorRelayIndex": existingRelay.LocalIndex,
 						"relay":               relay}).

hostmap.go

@@ -2,6 +2,7 @@ package nebula
 
 import (
 	"errors"
+	"fmt"
 	"net"
 	"net/netip"
 	"slices"
@@ -521,6 +522,7 @@ func (hm *HostMap) QueryVpnAddrsRelayFor(targetIps []netip.Addr, relayHostIp net
 		return nil, nil, errors.New("unable to find host")
 	}
 
+	lastH := h
 	for h != nil {
 		for _, targetIp := range targetIps {
 			r, ok := h.relayState.QueryRelayForByIp(targetIp)
@@ -528,10 +530,12 @@ func (hm *HostMap) QueryVpnAddrsRelayFor(targetIps []netip.Addr, relayHostIp net
 				return h, r, nil
 			}
 		}
+		lastH = h
 		h = h.next
 	}
 
-	return nil, nil, errors.New("unable to find host with relay")
+	//todo no merge
+	return nil, nil, fmt.Errorf("unable to find host with relay: %v", lastH)
 }
 
 func (hm *HostMap) unlockedDisestablishVpnAddrRelayFor(hi *HostInfo) {

lighthouse.go

@@ -21,7 +21,6 @@ import (
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/udp"
 	"github.com/slackhq/nebula/util"
-	"github.com/vishvananda/netlink"
 )
 
 var ErrHostNotKnown = errors.New("host not known")
@@ -58,7 +57,7 @@ type LightHouse struct {
 	// staticList exists to avoid having a bool in each addrMap entry
 	// since static should be rare
 	staticList  atomic.Pointer[map[netip.Addr]struct{}]
-	lighthouses atomic.Pointer[map[netip.Addr]struct{}]
+	lighthouses atomic.Pointer[[]netip.Addr]
 
 	interval     atomic.Int64
 	updateCancel context.CancelFunc
@@ -109,7 +108,7 @@ func NewLightHouseFromConfig(ctx context.Context, l *logrus.Logger, c *config.C,
 		queryChan:          make(chan netip.Addr, c.GetUint32("handshakes.query_buffer", 64)),
 		l:                  l,
 	}
-	lighthouses := make(map[netip.Addr]struct{})
+	lighthouses := make([]netip.Addr, 0)
 	h.lighthouses.Store(&lighthouses)
 	staticList := make(map[netip.Addr]struct{})
 	h.staticList.Store(&staticList)
@@ -145,7 +144,7 @@ func (lh *LightHouse) GetStaticHostList() map[netip.Addr]struct{} {
 	return *lh.staticList.Load()
 }
 
-func (lh *LightHouse) GetLighthouses() map[netip.Addr]struct{} {
+func (lh *LightHouse) GetLighthouses() []netip.Addr {
 	return *lh.lighthouses.Load()
 }
 
@@ -230,7 +229,7 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 				lh.updateCancel()
 			}
 
-			lh.StartUpdateWorkerNetlink()
+			lh.StartUpdateWorker()
 		}
 	}
 
@@ -308,13 +307,12 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 	}
 
 	if initial || c.HasChanged("lighthouse.hosts") {
-		lhMap := make(map[netip.Addr]struct{})
+		lhList, err := lh.parseLighthouses(c)
-		err := lh.parseLighthouses(c, lhMap)
 		if err != nil {
 			return err
 		}
 
-		lh.lighthouses.Store(&lhMap)
+		lh.lighthouses.Store(&lhList)
 		if !initial {
 			//NOTE: we are not tearing down existing lighthouse connections because they might be used for non lighthouse traffic
 			lh.l.Info("lighthouse.hosts has changed")
@@ -348,36 +346,37 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 	return nil
 }
 
-func (lh *LightHouse) parseLighthouses(c *config.C, lhMap map[netip.Addr]struct{}) error {
+func (lh *LightHouse) parseLighthouses(c *config.C) ([]netip.Addr, error) {
 	lhs := c.GetStringSlice("lighthouse.hosts", []string{})
 	if lh.amLighthouse && len(lhs) != 0 {
 		lh.l.Warn("lighthouse.am_lighthouse enabled on node but upstream lighthouses exist in config")
 	}
+	out := make([]netip.Addr, len(lhs))
 
 	for i, host := range lhs {
 		addr, err := netip.ParseAddr(host)
 		if err != nil {
-			return util.NewContextualError("Unable to parse lighthouse host entry", m{"host": host, "entry": i + 1}, err)
+			return nil, util.NewContextualError("Unable to parse lighthouse host entry", m{"host": host, "entry": i + 1}, err)
 		}
 
 		if !lh.myVpnNetworksTable.Contains(addr) {
-			return util.NewContextualError("lighthouse host is not in our networks, invalid", m{"vpnAddr": addr, "networks": lh.myVpnNetworks}, nil)
+			return nil, util.NewContextualError("lighthouse host is not in our networks, invalid", m{"vpnAddr": addr, "networks": lh.myVpnNetworks}, nil)
 		}
-		lhMap[addr] = struct{}{}
+		out[i] = addr
 	}
 
-	if !lh.amLighthouse && len(lhMap) == 0 {
+	if !lh.amLighthouse && len(out) == 0 {
 		lh.l.Warn("No lighthouse.hosts configured, this host will only be able to initiate tunnels with static_host_map entries")
 	}
 
 	staticList := lh.GetStaticHostList()
-	for lhAddr, _ := range lhMap {
+	for i := range out {
-		if _, ok := staticList[lhAddr]; !ok {
+		if _, ok := staticList[out[i]]; !ok {
-			return fmt.Errorf("lighthouse %s does not have a static_host_map entry", lhAddr)
+			return nil, fmt.Errorf("lighthouse %s does not have a static_host_map entry", out[i])
 		}
 	}
 
-	return nil
+	return out, nil
 }
 
 func getStaticMapCadence(c *config.C) (time.Duration, error) {
@@ -488,7 +487,7 @@ func (lh *LightHouse) QueryCache(vpnAddrs []netip.Addr) *RemoteList {
 	lh.Lock()
 	defer lh.Unlock()
 	// Add an entry if we don't already have one
-	return lh.unlockedGetRemoteList(vpnAddrs)
+	return lh.unlockedGetRemoteList(vpnAddrs) //todo CERT-V2 this contains addrmap lookups we could potentially skip
 }
 
 // queryAndPrepMessage is a lock helper on RemoteList, assisting the caller to build a lighthouse message containing
@@ -571,7 +570,7 @@ func (lh *LightHouse) addStaticRemotes(i int, d time.Duration, network string, t
 	am.unlockedSetHostnamesResults(hr)
 
 	for _, addrPort := range hr.GetAddrs() {
-		if !lh.shouldAdd(vpnAddr, addrPort.Addr()) {
+		if !lh.shouldAdd([]netip.Addr{vpnAddr}, addrPort.Addr()) {
 			continue
 		}
 		switch {
@@ -646,18 +645,17 @@ func (lh *LightHouse) unlockedGetRemoteList(allAddrs []netip.Addr) *RemoteList {
 		}
 	}
 
-	//TODO lighthouse.remote_allow_ranges is almost certainly broken in a multiple-address-per-cert scenario
+	am := NewRemoteList(allAddrs, lh.shouldAdd)
-	am := NewRemoteList(allAddrs, func(a netip.Addr) bool { return lh.shouldAdd(allAddrs[0], a) })
 	for _, addr := range allAddrs {
 		lh.addrMap[addr] = am
 	}
 	return am
 }
 
-func (lh *LightHouse) shouldAdd(vpnAddr netip.Addr, to netip.Addr) bool {
+func (lh *LightHouse) shouldAdd(vpnAddrs []netip.Addr, to netip.Addr) bool {
-	allow := lh.GetRemoteAllowList().Allow(vpnAddr, to)
+	allow := lh.GetRemoteAllowList().AllowAll(vpnAddrs, to)
 	if lh.l.Level >= logrus.TraceLevel {
-		lh.l.WithField("vpnAddr", vpnAddr).WithField("udpAddr", to).WithField("allow", allow).
+		lh.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", to).WithField("allow", allow).
 			Trace("remoteAllowList.Allow")
 	}
 	if !allow {
@@ -712,15 +710,22 @@ func (lh *LightHouse) unlockedShouldAddV6(vpnAddr netip.Addr, to *V6AddrPort) bo
 }
 
 func (lh *LightHouse) IsLighthouseAddr(vpnAddr netip.Addr) bool {
-	_, ok := lh.GetLighthouses()[vpnAddr]
+	l := lh.GetLighthouses()
-	return ok
+	for i := range l {
+		if l[i] == vpnAddr {
+			return true
+		}
+	}
+	return false
 }
 
-func (lh *LightHouse) IsAnyLighthouseAddr(vpnAddr []netip.Addr) bool {
+func (lh *LightHouse) IsAnyLighthouseAddr(vpnAddrs []netip.Addr) bool {
 	l := lh.GetLighthouses()
-	for _, a := range vpnAddr {
+	for i := range vpnAddrs {
-		if _, ok := l[a]; ok {
+		for j := range l {
-			return true
+			if l[j] == vpnAddrs[i] {
+				return true
+			}
 		}
 	}
 	return false
@@ -762,7 +767,7 @@ func (lh *LightHouse) innerQueryServer(addr netip.Addr, nb, out []byte) {
 	queried := 0
 	lighthouses := lh.GetLighthouses()
 
-	for lhVpnAddr := range lighthouses {
+	for _, lhVpnAddr := range lighthouses {
 		hi := lh.ifce.GetHostInfo(lhVpnAddr)
 		if hi != nil {
 			v = hi.ConnectionState.myCert.Version()
@@ -846,65 +851,10 @@ func (lh *LightHouse) StartUpdateWorker() {
 	}()
 }
 
-func (lh *LightHouse) StartUpdateWorkerNetlink() {
-	if lh.amLighthouse {
-		return
-	}
-
-	addrChan := make(chan netlink.AddrUpdate)
-	doneChan := make(chan struct{})
-
-	err := netlink.AddrSubscribe(addrChan, doneChan)
-	if err != nil {
-		lh.l.WithError(err).Error("Failed to subscribe to address updates")
-		return
-	}
-
-	updateCtx, cancel := context.WithCancel(lh.ctx)
-	lh.updateCancel = cancel
-
-	go func() {
-		defer func() {
-			x := struct{}{}
-			doneChan <- x
-		}()
-
-		lh.SendUpdate()
-
-		for {
-			select {
-			case <-updateCtx.Done():
-				return
-			case a := <-addrChan:
-				addr, ok := netip.AddrFromSlice(a.LinkAddress.IP)
-				if !ok {
-					continue
-				}
-				ones, _ := a.LinkAddress.Mask.Size()
-				pfx := netip.PrefixFrom(addr, ones)
-				lh.l.WithFields(logrus.Fields{
-					"LinkAddress": pfx,
-					"LinkIndex":   a.LinkIndex,
-					"Flags":       a.Flags,
-					"Scope":       a.Scope,
-					"NewAddr":     a.NewAddr,
-					"ValidLft":    a.ValidLft,
-					"PreferedLft": a.PreferedLft,
-				}).Warn("Received address update")
-
-				shouldSend := a.PreferedLft != 0 //example criteria
-				if shouldSend {
-					lh.SendUpdate()
-				}
-			}
-		}
-	}()
-}
-
 func (lh *LightHouse) SendUpdate() {
 	var v4 []*V4AddrPort
 	var v6 []*V6AddrPort
-	lh.l.Warn("sending lh update!")
+
 	for _, e := range lh.GetAdvertiseAddrs() {
 		if e.Addr().Is4() {
 			v4 = append(v4, netAddrToProtoV4AddrPort(e.Addr(), e.Port()))
@@ -935,7 +885,7 @@ func (lh *LightHouse) SendUpdate() {
 	updated := 0
 	lighthouses := lh.GetLighthouses()
 
-	for lhVpnAddr := range lighthouses {
+	for _, lhVpnAddr := range lighthouses {
 		var v cert.Version
 		hi := lh.ifce.GetHostInfo(lhVpnAddr)
 		if hi != nil {
@@ -993,7 +943,6 @@ func (lh *LightHouse) SendUpdate() {
 						V4AddrPorts:   v4,
 						V6AddrPorts:   v6,
 						RelayVpnAddrs: relays,
-						VpnAddr:       netAddrToProtoAddr(lh.myVpnNetworks[0].Addr()),
 					},
 				}
 
@@ -1116,7 +1065,16 @@ func (lhh *LightHouseHandler) handleHostQuery(n *NebulaMeta, fromVpnAddrs []neti
 	queryVpnAddr, useVersion, err := n.Details.GetVpnAddrAndVersion()
 	if err != nil {
 		if lhh.l.Level >= logrus.DebugLevel {
-			lhh.l.WithField("from", fromVpnAddrs).WithField("details", n.Details).Debugln("Dropping malformed HostQuery")
+			lhh.l.WithField("from", fromVpnAddrs).WithField("details", n.Details).
+				Debugln("Dropping malformed HostQuery")
+		}
+		return
+	}
+	if useVersion == cert.Version1 && queryVpnAddr.Is6() {
+		// this case really shouldn't be possible to represent, but reject it anyway.
+		if lhh.l.Level >= logrus.DebugLevel {
+			lhh.l.WithField("vpnAddrs", fromVpnAddrs).WithField("queryVpnAddr", queryVpnAddr).
+				Debugln("invalid vpn addr for v1 handleHostQuery")
 		}
 		return
 	}
@@ -1125,9 +1083,6 @@ func (lhh *LightHouseHandler) handleHostQuery(n *NebulaMeta, fromVpnAddrs []neti
 		n = lhh.resetMeta()
 		n.Type = NebulaMeta_HostQueryReply
 		if useVersion == cert.Version1 {
-			if !queryVpnAddr.Is4() {
-				return 0, fmt.Errorf("invalid vpn addr for v1 handleHostQuery")
-			}
 			b := queryVpnAddr.As4()
 			n.Details.OldVpnAddr = binary.BigEndian.Uint32(b[:])
 		} else {
@@ -1287,16 +1242,24 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 		return
 	}
 
-	detailsVpnAddr, useVersion, err := n.Details.GetVpnAddrAndVersion()
+	// not using GetVpnAddrAndVersion because we don't want to error on a blank detailsVpnAddr
-	if err != nil {
+	var detailsVpnAddr netip.Addr
-		if lhh.l.Level >= logrus.DebugLevel {
+	var useVersion cert.Version
-			lhh.l.WithField("details", n.Details).WithError(err).Debugln("dropping invalid HostUpdateNotification")
+	if n.Details.OldVpnAddr != 0 { //v1 always sets this field
-		}
+		b := [4]byte{}
+		binary.BigEndian.PutUint32(b[:], n.Details.OldVpnAddr)
+		detailsVpnAddr = netip.AddrFrom4(b)
+		useVersion = cert.Version1
+	} else if n.Details.VpnAddr != nil { //this field is "optional" in v2, but if it's set, we should enforce it
+		detailsVpnAddr = protoAddrToNetAddr(n.Details.VpnAddr)
+		useVersion = cert.Version2
+	} else {
+		detailsVpnAddr = netip.Addr{}
+		useVersion = cert.Version2
 	}
 
-	//TODO: CERT-V2 why do we care about the vpnAddr in the packet? We know where it came from, right?
+	//Simple check that the host sent this not someone else, if detailsVpnAddr is filled
-	//Simple check that the host sent this not someone else
+	if detailsVpnAddr.IsValid() && !slices.Contains(fromVpnAddrs, detailsVpnAddr) {
-	if !slices.Contains(fromVpnAddrs, detailsVpnAddr) {
 		if lhh.l.Level >= logrus.DebugLevel {
 			lhh.l.WithField("vpnAddrs", fromVpnAddrs).WithField("answer", detailsVpnAddr).Debugln("Host sent invalid update")
 		}
@@ -1310,24 +1273,24 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 	am.Lock()
 	lhh.lh.Unlock()
 
-	am.unlockedSetV4(fromVpnAddrs[0], detailsVpnAddr, n.Details.V4AddrPorts, lhh.lh.unlockedShouldAddV4)
+	am.unlockedSetV4(fromVpnAddrs[0], fromVpnAddrs[0], n.Details.V4AddrPorts, lhh.lh.unlockedShouldAddV4)
-	am.unlockedSetV6(fromVpnAddrs[0], detailsVpnAddr, n.Details.V6AddrPorts, lhh.lh.unlockedShouldAddV6)
+	am.unlockedSetV6(fromVpnAddrs[0], fromVpnAddrs[0], n.Details.V6AddrPorts, lhh.lh.unlockedShouldAddV6)
 	am.unlockedSetRelay(fromVpnAddrs[0], relays)
 	am.Unlock()
 
 	n = lhh.resetMeta()
 	n.Type = NebulaMeta_HostUpdateNotificationAck
-
+	switch useVersion {
-	if useVersion == cert.Version1 {
+	case cert.Version1:
 		if !fromVpnAddrs[0].Is4() {
 			lhh.l.WithField("vpnAddrs", fromVpnAddrs).Error("Can not send HostUpdateNotificationAck for a ipv6 vpn ip in a v1 message")
 			return
 		}
 		vpnAddrB := fromVpnAddrs[0].As4()
 		n.Details.OldVpnAddr = binary.BigEndian.Uint32(vpnAddrB[:])
-	} else if useVersion == cert.Version2 {
+	case cert.Version2:
-		n.Details.VpnAddr = netAddrToProtoAddr(fromVpnAddrs[0])
+		// do nothing, we want to send a blank message
-	} else {
+	default:
 		lhh.l.WithField("useVersion", useVersion).Error("invalid protocol version")
 		return
 	}
@@ -1345,7 +1308,6 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 func (lhh *LightHouseHandler) handleHostPunchNotification(n *NebulaMeta, fromVpnAddrs []netip.Addr, w EncWriter) {
 	//It's possible the lighthouse is communicating with us using a non primary vpn addr,
 	//which means we need to compare all fromVpnAddrs against all configured lighthouse vpn addrs.
-	//maybe one day we'll have a better idea, if it matters.
 	if !lhh.lh.IsAnyLighthouseAddr(fromVpnAddrs) {
 		return
 	}

main.go

@@ -291,7 +291,7 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		sshStart,
 		statsStart,
 		dnsStart,
-		lightHouse.StartUpdateWorkerNetlink,
+		lightHouse.StartUpdateWorker,
 		connManager.Start,
 	}, nil
 }

pkclient/pkclient_cgo.go

@@ -180,6 +180,7 @@ func (c *PKClient) DeriveNoise(peerPubKey []byte) ([]byte, error) {
 		pkcs11.NewAttribute(pkcs11.CKA_DECRYPT, true),
 		pkcs11.NewAttribute(pkcs11.CKA_WRAP, true),
 		pkcs11.NewAttribute(pkcs11.CKA_UNWRAP, true),
+		pkcs11.NewAttribute(pkcs11.CKA_VALUE_LEN, NoiseKeySize),
 	}
 
 	// Set up the parameters which include the peer's public key

pki.go

@@ -100,55 +100,62 @@ func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
 		currentState := p.cs.Load()
 		if newState.v1Cert != nil {
 			if currentState.v1Cert == nil {
-				return util.NewContextualError("v1 certificate was added, restart required", nil, err)
+				//adding certs is fine, actually. Networks-in-common confirmed in newCertState().
-			}
+			} else {
+				// did IP in cert change? if so, don't set
+				if !slices.Equal(currentState.v1Cert.Networks(), newState.v1Cert.Networks()) {
+					return util.NewContextualError(
+						"Networks in new cert was different from old",
+						m{"new_networks": newState.v1Cert.Networks(), "old_networks": currentState.v1Cert.Networks(), "cert_version": cert.Version1},
+						nil,
+					)
+				}
 
-			// did IP in cert change? if so, don't set
+				if currentState.v1Cert.Curve() != newState.v1Cert.Curve() {
-			if !slices.Equal(currentState.v1Cert.Networks(), newState.v1Cert.Networks()) {
+					return util.NewContextualError(
-				return util.NewContextualError(
+						"Curve in new v1 cert was different from old",
-					"Networks in new cert was different from old",
+						m{"new_curve": newState.v1Cert.Curve(), "old_curve": currentState.v1Cert.Curve(), "cert_version": cert.Version1},
-					m{"new_networks": newState.v1Cert.Networks(), "old_networks": currentState.v1Cert.Networks()},
+						nil,
-					nil,
+					)
-				)
+				}
 			}
-
-			if currentState.v1Cert.Curve() != newState.v1Cert.Curve() {
-				return util.NewContextualError(
-					"Curve in new cert was different from old",
-					m{"new_curve": newState.v1Cert.Curve(), "old_curve": currentState.v1Cert.Curve()},
-					nil,
-				)
-			}
-
-		} else if currentState.v1Cert != nil {
-			//TODO: CERT-V2 we should be able to tear this down
-			return util.NewContextualError("v1 certificate was removed, restart required", nil, err)
 		}
 
 		if newState.v2Cert != nil {
 			if currentState.v2Cert == nil {
-				return util.NewContextualError("v2 certificate was added, restart required", nil, err)
+				//adding certs is fine, actually
-			}
+			} else {
+				// did IP in cert change? if so, don't set
+				if !slices.Equal(currentState.v2Cert.Networks(), newState.v2Cert.Networks()) {
+					return util.NewContextualError(
+						"Networks in new cert was different from old",
+						m{"new_networks": newState.v2Cert.Networks(), "old_networks": currentState.v2Cert.Networks(), "cert_version": cert.Version2},
+						nil,
+					)
+				}
 
-			// did IP in cert change? if so, don't set
+				if currentState.v2Cert.Curve() != newState.v2Cert.Curve() {
-			if !slices.Equal(currentState.v2Cert.Networks(), newState.v2Cert.Networks()) {
+					return util.NewContextualError(
-				return util.NewContextualError(
+						"Curve in new cert was different from old",
-					"Networks in new cert was different from old",
+						m{"new_curve": newState.v2Cert.Curve(), "old_curve": currentState.v2Cert.Curve(), "cert_version": cert.Version2},
-					m{"new_networks": newState.v2Cert.Networks(), "old_networks": currentState.v2Cert.Networks()},
+						nil,
-					nil,
+					)
-				)
+				}
-			}
-
-			if currentState.v2Cert.Curve() != newState.v2Cert.Curve() {
-				return util.NewContextualError(
-					"Curve in new cert was different from old",
-					m{"new_curve": newState.v2Cert.Curve(), "old_curve": currentState.v2Cert.Curve()},
-					nil,
-				)
 			}
 
 		} else if currentState.v2Cert != nil {
-			return util.NewContextualError("v2 certificate was removed, restart required", nil, err)
+			//newState.v1Cert is non-nil bc empty certstates aren't permitted
+			if newState.v1Cert == nil {
+				return util.NewContextualError("v1 and v2 certs are nil, this should be impossible", nil, err)
+			}
+			//if we're going to v1-only, we need to make sure we didn't orphan any v2-cert vpnaddrs
+			if !slices.Equal(currentState.v2Cert.Networks(), newState.v1Cert.Networks()) {
+				return util.NewContextualError(
+					"Removing a V2 cert is not permitted unless it has identical networks to the new V1 cert",
+					m{"new_v1_networks": newState.v1Cert.Networks(), "old_v2_networks": currentState.v2Cert.Networks()},
+					nil,
+				)
+			}
 		}
 
 		// Cipher cant be hot swapped so just leave it at what it was before

relay_manager.go

@@ -190,6 +190,7 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 			InitiatorRelayIndex: peerRelay.RemoteIndex,
 		}
 
+		relayFrom := h.vpnAddrs[0]
 		if v == cert.Version1 {
 			peer := peerHostInfo.vpnAddrs[0]
 			if !peer.Is4() {
@@ -207,7 +208,13 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 			b = targetAddr.As4()
 			resp.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 		} else {
-			resp.RelayFromAddr = netAddrToProtoAddr(peerHostInfo.vpnAddrs[0])
+			if targetAddr.Is4() {
+				relayFrom = h.vpnAddrs[0]
+			} else {
+				//todo do this smarter
+				relayFrom = h.vpnAddrs[len(h.vpnAddrs)-1]
+			}
+			resp.RelayFromAddr = netAddrToProtoAddr(relayFrom)
 			resp.RelayToAddr = target
 		}
 
@@ -360,7 +367,7 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 			Type:                NebulaControl_CreateRelayRequest,
 			InitiatorRelayIndex: index,
 		}
-
+		relayFrom := h.vpnAddrs[0]
 		if v == cert.Version1 {
 			if !h.vpnAddrs[0].Is4() {
 				rm.l.WithField("relayFrom", h.vpnAddrs[0]).
@@ -377,7 +384,13 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 			b = target.As4()
 			req.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 		} else {
-			req.RelayFromAddr = netAddrToProtoAddr(h.vpnAddrs[0])
+			if target.Is4() {
+				relayFrom = h.vpnAddrs[0]
+			} else {
+				//todo do this smarter
+				relayFrom = h.vpnAddrs[len(h.vpnAddrs)-1]
+			}
+			req.RelayFromAddr = netAddrToProtoAddr(relayFrom)
 			req.RelayToAddr = netAddrToProtoAddr(target)
 		}
 
@@ -388,7 +401,7 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 		} else {
 			f.SendMessageToHostInfo(header.Control, 0, peer, msg, make([]byte, 12), make([]byte, mtu))
 			rm.l.WithFields(logrus.Fields{
-				"relayFrom":           h.vpnAddrs[0],
+				"relayFrom":           relayFrom,
 				"relayTo":             target,
 				"initiatorRelayIndex": req.InitiatorRelayIndex,
 				"responderRelayIndex": req.ResponderRelayIndex,

remote_list.go

@@ -190,7 +190,7 @@ type RemoteList struct {
 	// The full list of vpn addresses assigned to this host
 	vpnAddrs []netip.Addr
 
-	// A deduplicated set of addresses. Any accessor should lock beforehand.
+	// A deduplicated set of underlay addresses. Any accessor should lock beforehand.
 	addrs []netip.AddrPort
 
 	// A set of relay addresses. VpnIp addresses that the remote identified as relays.
@@ -201,8 +201,10 @@ type RemoteList struct {
 	// For learned addresses, this is the vpnIp that sent the packet
 	cache map[netip.Addr]*cache
 
-	hr        *hostnamesResults
+	hr *hostnamesResults
-	shouldAdd func(netip.Addr) bool
+
+	// shouldAdd is a nillable function that decides if x should be added to addrs.
+	shouldAdd func(vpnAddrs []netip.Addr, x netip.Addr) bool
 
 	// This is a list of remotes that we have tried to handshake with and have returned from the wrong vpn ip.
 	// They should not be tried again during a handshake
@@ -213,7 +215,7 @@ type RemoteList struct {
 }
 
 // NewRemoteList creates a new empty RemoteList
-func NewRemoteList(vpnAddrs []netip.Addr, shouldAdd func(netip.Addr) bool) *RemoteList {
+func NewRemoteList(vpnAddrs []netip.Addr, shouldAdd func([]netip.Addr, netip.Addr) bool) *RemoteList {
 	r := &RemoteList{
 		vpnAddrs:  make([]netip.Addr, len(vpnAddrs)),
 		addrs:     make([]netip.AddrPort, 0),
@@ -368,6 +370,15 @@ func (r *RemoteList) CopyBlockedRemotes() []netip.AddrPort {
 	return c
 }
 
+// RefreshFromHandshake locks and updates the RemoteList to account for data learned upon a completed handshake
+func (r *RemoteList) RefreshFromHandshake(vpnAddrs []netip.Addr) {
+	r.Lock()
+	r.badRemotes = nil
+	r.vpnAddrs = make([]netip.Addr, len(vpnAddrs))
+	copy(r.vpnAddrs, vpnAddrs)
+	r.Unlock()
+}
+
 // ResetBlockedRemotes locks and clears the blocked remotes list
 func (r *RemoteList) ResetBlockedRemotes() {
 	r.Lock()
@@ -577,7 +588,7 @@ func (r *RemoteList) unlockedCollect() {
 
 	dnsAddrs := r.hr.GetAddrs()
 	for _, addr := range dnsAddrs {
-		if r.shouldAdd == nil || r.shouldAdd(addr.Addr()) {
+		if r.shouldAdd == nil || r.shouldAdd(r.vpnAddrs, addr.Addr()) {
 			if !r.unlockedIsBad(addr) {
 				addrs = append(addrs, addr)
 			}