Remove TLS root validation

This is just too complicated compared to the per-peer/per-listener/per-interface password
approach.

cmd/yggdrasil/main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"crypto/ed25519"
-	"crypto/sha1"
 	"encoding/hex"
 	"encoding/json"
 	"flag"
@@ -45,8 +44,6 @@ func main() {
 	useconffile := flag.String("useconffile", "", "read HJSON/JSON config from specified file path")
 	normaliseconf := flag.Bool("normaliseconf", false, "use in combination with either -useconf or -useconffile, outputs your configuration normalised")
 	exportkey := flag.Bool("exportkey", false, "use in combination with either -useconf or -useconffile, outputs your private key in PEM format")
-	exportcsr := flag.Bool("exportcsr", false, "use in combination with either -useconf or -useconffile, outputs your self-signed certificate request in PEM format")
-	exportcert := flag.Bool("exportcert", false, "use in combination with either -useconf or -useconffile, outputs your self-signed certificate in PEM format")
 	confjson := flag.Bool("json", false, "print configuration from -genconf or -normaliseconf as JSON instead of HJSON")
 	autoconf := flag.Bool("autoconf", false, "automatic mode (dynamic IP, peer with IPv6 neighbors)")
 	ver := flag.Bool("version", false, "prints the version of this build")
@@ -177,30 +174,10 @@ func main() {
 		}
 		fmt.Println(string(pem))
 		return
-
-	case *exportcsr:
-		pem, err := cfg.GenerateCertificateSigningRequest()
-		if err != nil {
-			panic(err)
-		}
-		fmt.Println(string(pem))
-		return
-
-	case *exportcert:
-		pem, err := cfg.MarshalPEMCertificate()
-		if err != nil {
-			panic(err)
-		}
-		fmt.Println(string(pem))
-		return
 	}
 
 	n := &node{}
 
-	// Track certificate fingerprints for configured roots, so
-	// that we can match them using the multicast discriminator.
-	fingerprints := map[[20]byte]struct{}{}
-
 	// Setup the Yggdrasil node itself.
 	{
 		options := []core.SetupOption{
@@ -218,10 +195,6 @@ func main() {
 				options = append(options, core.Peer{URI: peer, SourceInterface: intf})
 			}
 		}
-		for _, root := range cfg.RootCertificates {
-			options = append(options, core.RootCertificate(*root))
-			fingerprints[sha1.Sum(root.Raw[:])] = struct{}{}
-		}
 		for _, allowed := range cfg.AllowedPublicKeys {
 			k, err := hex.DecodeString(allowed)
 			if err != nil {
@@ -259,29 +232,6 @@ func main() {
 				Priority: uint8(intf.Priority),
 			})
 		}
-		if len(fingerprints) > 0 {
-			var matcher multicast.DiscriminatorMatch = func(b []byte) bool {
-				// Break apart the discriminator into 20-byte chunks and
-				// see whether any of them match the configured root CA
-				// fingerprints. If any of them match, we'll return true.
-				var f [20]byte
-				for len(b) >= len(f) {
-					b = b[copy(f[:], b):]
-					if _, ok := fingerprints[f]; ok {
-						return true
-					}
-				}
-				return false
-			}
-			// Populate our own discriminator with the fingerprints of our
-			// configured root CAs.
-			var discriminator multicast.Discriminator
-			for f := range fingerprints {
-				discriminator = append(discriminator, f[:]...)
-			}
-			options = append(options, matcher)
-			options = append(options, discriminator)
-		}
 		if n.multicast, err = multicast.New(n.core, logger, options...); err != nil {
 			panic(err)
 		}

contrib/mobile/mobile.go

@@ -70,9 +70,6 @@ func (m *Yggdrasil) StartJSON(configjson []byte) error {
 			}
 			options = append(options, core.AllowedPublicKey(k[:]))
 		}
-		for _, root := range m.config.RootCertificates {
-			options = append(options, core.RootCertificate(*root))
-		}
 		var err error
 		m.core, err = core.New(m.config.Certificate, logger, options...)
 		if err != nil {

src/config/config.go

@@ -43,9 +43,6 @@ type NodeConfig struct {
 	PrivateKey          KeyBytes                   `comment:"Your private key. DO NOT share this with anyone!"`
 	PrivateKeyPath      string                     `json:",omitempty"`
 	Certificate         *tls.Certificate           `json:"-"`
-	CertificatePath      string                     `json:",omitempty"`
-	RootCertificates     []*x509.Certificate        `json:"-"`
-	RootCertificatePaths []string                   `json:",omitempty"`
 	Peers               []string                   `comment:"List of connection strings for outbound peer connections in URI format,\ne.g. tls://a.b.c.d:e or socks://a.b.c.d:e/f.g.h.i:j. These connections\nwill obey the operating system routing table, therefore you should\nuse this section when you may connect via different interfaces."`
 	InterfacePeers      map[string][]string        `comment:"List of connection strings for outbound peer connections in URI format,\narranged by source interface, e.g. { \"eth0\": [ \"tls://a.b.c.d:e\" ] }.\nNote that SOCKS peerings will NOT be affected by this option and should\ngo in the \"Peers\" section instead."`
 	Listen              []string                   `comment:"Listen addresses for incoming connections. You will need to add\nlisteners in order to accept incoming peerings from non-local nodes.\nMulticast peer discovery will work regardless of any listeners set\nhere. Each listener should be specified in URI format as above, e.g.\ntls://0.0.0.0:0 or tls://[::]:0 to listen on all interfaces."`
@@ -138,19 +135,6 @@ func (cfg *NodeConfig) postprocessConfig() error {
 			return err
 		}
 	}
-	if cfg.CertificatePath != "" {
-		if cfg.PrivateKeyPath == "" {
-			return fmt.Errorf("CertificatePath requires PrivateKeyPath")
-		}
-		cfg.Certificate = nil
-		f, err := os.ReadFile(cfg.CertificatePath)
-		if err != nil {
-			return err
-		}
-		if err := cfg.UnmarshalPEMCertificate(f); err != nil {
-			return err
-		}
-	}
 	switch {
 	case cfg.Certificate == nil:
 		// No self-signed certificate has been generated yet.
@@ -163,35 +147,6 @@ func (cfg *NodeConfig) postprocessConfig() error {
 			return err
 		}
 	}
-	cfg.RootCertificates = cfg.RootCertificates[:0]
-	for _, path := range cfg.RootCertificatePaths {
-		f, err := os.ReadFile(path)
-		if err != nil {
-			return err
-		}
-		if err := cfg.UnmarshalRootCertificate(f); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func (cfg *NodeConfig) UnmarshalRootCertificate(b []byte) error {
-	p, _ := pem.Decode(b)
-	if p == nil {
-		return fmt.Errorf("failed to parse PEM file")
-	}
-	if p.Type != "CERTIFICATE" {
-		return fmt.Errorf("unexpected PEM type %q", p.Type)
-	}
-	cert, err := x509.ParseCertificate(p.Bytes)
-	if err != nil {
-		return fmt.Errorf("failed to load X.509 keypair: %w", err)
-	}
-	if !cert.IsCA {
-		return fmt.Errorf("supplied root certificate is not a certificate authority")
-	}
-	cfg.RootCertificates = append(cfg.RootCertificates, cert)
 	return nil
 }
 
@@ -215,26 +170,6 @@ func (cfg *NodeConfig) GenerateSelfSignedCertificate() error {
 	return nil
 }
 
-func (cfg *NodeConfig) GenerateCertificateSigningRequest() ([]byte, error) {
-	template := &x509.CertificateRequest{
-		Subject: pkix.Name{
-			CommonName: hex.EncodeToString(cfg.PrivateKey),
-		},
-		SignatureAlgorithm: x509.PureEd25519,
-	}
-
-	csrBytes, err := x509.CreateCertificateRequest(rand.Reader, template, ed25519.PrivateKey(cfg.PrivateKey))
-	if err != nil {
-		return nil, err
-	}
-
-	pemBytes := bytes.NewBuffer(nil)
-	if err := pem.Encode(pemBytes, &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: csrBytes}); err != nil {
-		return nil, err
-	}
-	return pemBytes.Bytes(), nil
-}
-
 func (cfg *NodeConfig) MarshalPEMCertificate() ([]byte, error) {
 	privateKey := ed25519.PrivateKey(cfg.PrivateKey)
 	publicKey := privateKey.Public().(ed25519.PublicKey)
@@ -263,15 +198,6 @@ func (cfg *NodeConfig) MarshalPEMCertificate() ([]byte, error) {
 	return pem.EncodeToMemory(block), nil
 }
 
-func (cfg *NodeConfig) UnmarshalPEMCertificate(b []byte) error {
-	tlsCert, err := tls.LoadX509KeyPair(cfg.CertificatePath, cfg.PrivateKeyPath)
-	if err != nil {
-		return fmt.Errorf("failed to load X.509 keypair: %w", err)
-	}
-	cfg.Certificate = &tlsCert
-	return nil
-}
-
 func (cfg *NodeConfig) NewPrivateKey() {
 	_, spriv, err := ed25519.GenerateKey(nil)
 	if err != nil {

src/core/core.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"crypto/ed25519"
 	"crypto/tls"
-	"crypto/x509"
 	"encoding/hex"
 	"fmt"
 	"io"
@@ -40,7 +39,6 @@ type Core struct {
 	addPeerTimer *time.Timer
 	config       struct {
 		tls *tls.Config // immutable after startup
-		roots *x509.CertPool // immutable after startup
 		//_peers             map[Peer]*linkInfo         // configurable after startup
 		_listeners         map[ListenAddress]struct{} // configurable after startup
 		nodeinfo           NodeInfo                   // immutable after startup
@@ -110,9 +108,6 @@ func New(cert *tls.Certificate, logger Logger, opts ...SetupOption) (*Core, erro
 	c.log.Infof("Your public key is %s", hex.EncodeToString(c.public))
 	c.log.Infof("Your IPv6 address is %s", address.String())
 	c.log.Infof("Your IPv6 subnet is %s", subnet.String())
-	if c.config.roots != nil {
-		c.log.Println("Yggdrasil is running in TLS-only mode")
-	}
 	c.proto.init(c)
 	if err := c.links.init(c); err != nil {
 		return nil, fmt.Errorf("error initialising links: %w", err)
@@ -169,10 +164,6 @@ func (c *Core) _close() error {
 	return err
 }
 
-func (c *Core) isTLSOnly() bool {
-	return c.config.roots != nil
-}
-
 func (c *Core) MTU() uint64 {
 	const sessionTypeOverhead = 1
 	MTU := c.PacketConn.MTU() - sessionTypeOverhead

src/core/link_tcp.go

@@ -69,9 +69,6 @@ func (l *linkTCP) dialersFor(url *url.URL, info linkInfo) ([]*tcpDialer, error)
 }
 
 func (l *linkTCP) dial(ctx context.Context, url *url.URL, info linkInfo, options linkOptions) (net.Conn, error) {
-	if l.core.isTLSOnly() {
-		return nil, fmt.Errorf("TCP peer prohibited in TLS-only mode")
-	}
 	dialers, err := l.dialersFor(url, info)
 	if err != nil {
 		return nil, err
@@ -92,9 +89,6 @@ func (l *linkTCP) dial(ctx context.Context, url *url.URL, info linkInfo, options
 }
 
 func (l *linkTCP) listen(ctx context.Context, url *url.URL, sintf string) (net.Listener, error) {
-	if l.core.isTLSOnly() {
-		return nil, fmt.Errorf("TCP listener prohibited in TLS-only mode")
-	}
 	hostport := url.Host
 	if sintf != "" {
 		if host, port, err := net.SplitHostPort(hostport); err == nil {

src/core/options.go

@@ -2,19 +2,12 @@ package core
 
 import (
 	"crypto/ed25519"
-	"crypto/x509"
 	"fmt"
 	"net/url"
 )
 
 func (c *Core) _applyOption(opt SetupOption) (err error) {
 	switch v := opt.(type) {
-	case RootCertificate:
-		cert := x509.Certificate(v)
-		if c.config.roots == nil {
-			c.config.roots = x509.NewCertPool()
-		}
-		c.config.roots.AddCert(&cert)
 	case Peer:
 		u, err := url.Parse(v.URI)
 		if err != nil {
@@ -39,7 +32,6 @@ type SetupOption interface {
 	isSetupOption()
 }
 
-type RootCertificate x509.Certificate
 type ListenAddress string
 type Peer struct {
 	URI             string
@@ -49,7 +41,6 @@ type NodeInfo map[string]interface{}
 type NodeInfoPrivacy bool
 type AllowedPublicKey ed25519.PublicKey
 
-func (a RootCertificate) isSetupOption()  {}
 func (a ListenAddress) isSetupOption()    {}
 func (a Peer) isSetupOption()             {}
 func (a NodeInfo) isSetupOption()         {}

src/core/tls.go

@@ -17,39 +17,20 @@ func (c *Core) generateTLSConfig(cert *tls.Certificate) (*tls.Config, error) {
 		VerifyConnection:      c.verifyTLSConnection,
 		InsecureSkipVerify:    true,
 		MinVersion:            tls.VersionTLS13,
-		NextProtos:            []string{"yggdrasil/0.5"},
+		NextProtos: []string{
+			fmt.Sprintf("yggdrasil/%d.%d", ProtocolVersionMajor, ProtocolVersionMinor),
+		},
 	}
 	return config, nil
 }
 
 func (c *Core) verifyTLSCertificate(rawCerts [][]byte, _ [][]*x509.Certificate) error {
-	if c.config.roots == nil {
+	if len(rawCerts) != 1 {
-		// If there's no certificate pool configured then we will
+		return fmt.Errorf("expected one certificate")
-		// accept all TLS certificates.
-		return nil
-	}
-	if len(rawCerts) == 0 {
-		return fmt.Errorf("expected at least one certificate")
-	}
-
-	opts := x509.VerifyOptions{
-		Roots: c.config.roots,
-	}
-
-	for i, rawCert := range rawCerts {
-		if i == 0 {
-			// The first certificate is the leaf certificate. All other
-			// certificates in the list are intermediates, so add them
-			// into the VerifyOptions.
-			continue
-		}
-		cert, err := x509.ParseCertificate(rawCert)
-		if err != nil {
-			return fmt.Errorf("failed to parse intermediate certificate: %w", err)
-		}
-		opts.Intermediates.AddCert(cert)
 	}
 
+	/*
+		opts := x509.VerifyOptions{}
 		cert, err := x509.ParseCertificate(rawCerts[0])
 		if err != nil {
 			return fmt.Errorf("failed to parse leaf certificate: %w", err)
@@ -57,6 +38,9 @@ func (c *Core) verifyTLSCertificate(rawCerts [][]byte, _ [][]*x509.Certificate)
 
 		_, err = cert.Verify(opts)
 		return err
+	*/
+
+	return nil
 }
 
 func (c *Core) verifyTLSConnection(cs tls.ConnectionState) error {