V2 certificate format

Makefile

@@ -196,7 +196,7 @@ bench-cpu-long:
 	go test -bench=. -benchtime=60s -cpuprofile=cpu.pprof
 	go tool pprof go-audit.test cpu.pprof
 
-proto: nebula.pb.go cert/cert.pb.go
+proto: nebula.pb.go cert/cert_v1.pb.go
 
 nebula.pb.go: nebula.proto .FORCE
 	go build github.com/gogo/protobuf/protoc-gen-gogofaster

cert/asn1.go

@@ -0,0 +1,52 @@
+package cert
+
+import (
+	"golang.org/x/crypto/cryptobyte"
+	"golang.org/x/crypto/cryptobyte/asn1"
+)
+
+// readOptionalASN1Boolean reads an asn.1 boolean with a specific tag instead of a asn.1 tag wrapping a boolean with a value
+// https://github.com/golang/go/issues/64811#issuecomment-1944446920
+func readOptionalASN1Boolean(b *cryptobyte.String, out *bool, tag asn1.Tag, defaultValue bool) bool {
+	var present bool
+	var child cryptobyte.String
+	if !b.ReadOptionalASN1(&child, &present, tag) {
+		return false
+	}
+
+	if !present {
+		*out = defaultValue
+		return true
+	}
+
+	// Ensure we have 1 byte
+	if len(child) == 1 {
+		*out = child[0] > 0
+		return true
+	}
+
+	return false
+}
+
+// readOptionalASN1Byte reads an asn.1 uint8 with a specific tag instead of a asn.1 tag wrapping a uint8 with a value
+// Similar issue as with readOptionalASN1Boolean
+func readOptionalASN1Byte(b *cryptobyte.String, out *byte, tag asn1.Tag, defaultValue byte) bool {
+	var present bool
+	var child cryptobyte.String
+	if !b.ReadOptionalASN1(&child, &present, tag) {
+		return false
+	}
+
+	if !present {
+		*out = defaultValue
+		return true
+	}
+
+	// Ensure we have 1 byte
+	if len(child) == 1 {
+		*out = child[0]
+		return true
+	}
+
+	return false
+}

cert/cert.go

@@ -1,15 +1,17 @@
 package cert
 
 import (
+	"fmt"
 	"net/netip"
 	"time"
 )
 
-type Version int
+type Version uint32
 
 const (
-	Version1 Version = 1
-	Version2 Version = 2
+	VersionPre1 Version = 0
+	Version1    Version = 1
+	Version2    Version = 2
 )
 
 type Certificate interface {
@@ -109,21 +111,62 @@ type CachedCertificate struct {
 
 // UnmarshalCertificate will attempt to unmarshal a wire protocol level certificate.
 func UnmarshalCertificate(b []byte) (Certificate, error) {
-	c, err := unmarshalCertificateV1(b, true)
-	if err != nil {
-		return nil, err
+	//TODO: you left off here, no one uses this function but it might be beneficial to export _something_ that someone can use, maybe the Versioned unmarshallsers?
+	var c Certificate
+	c, err := unmarshalCertificateV2(b, nil)
+	if err == nil {
+		return c, nil
 	}
-	return c, nil
+
+	c, err = unmarshalCertificateV1(b, nil)
+	if err == nil {
+		return c, nil
+	}
+
+	return nil, fmt.Errorf("could not unmarshal certificate")
 }
 
 // UnmarshalCertificateFromHandshake will attempt to unmarshal a certificate received in a handshake.
 // Handshakes save space by placing the peers public key in a different part of the packet, we have to
 // reassemble the actual certificate structure with that in mind.
-func UnmarshalCertificateFromHandshake(b []byte, publicKey []byte) (Certificate, error) {
-	c, err := unmarshalCertificateV1(b, false)
+func UnmarshalCertificateFromHandshake(v Version, b []byte, publicKey []byte) (Certificate, error) {
+	var c Certificate
+	var err error
+
+	switch v {
+	case VersionPre1, Version1:
+		c, err = unmarshalCertificateV1(b, publicKey)
+	case Version2:
+		c, err = unmarshalCertificateV2(b, publicKey)
+	default:
+		//TODO: make a static var
+		return nil, fmt.Errorf("unknown certificate version %d", v)
+	}
+
 	if err != nil {
 		return nil, err
 	}
-	c.details.PublicKey = publicKey
 	return c, nil
 }
+
+func RecombineAndValidate(v Version, rawCertBytes, publicKey []byte, caPool *CAPool) (*CachedCertificate, error) {
+	if publicKey == nil {
+		return nil, ErrNoPeerStaticKey
+	}
+
+	if rawCertBytes == nil {
+		return nil, ErrNoPayload
+	}
+
+	c, err := UnmarshalCertificateFromHandshake(v, rawCertBytes, publicKey)
+	if err != nil {
+		return nil, fmt.Errorf("error unmarshaling cert: %w", err)
+	}
+
+	cc, err := caPool.VerifyCertificate(time.Now(), c)
+	if err != nil {
+		return nil, fmt.Errorf("certificate validation failed: %w", err)
+	}
+
+	return cc, nil
+}

cert/cert_test.go

@@ -51,7 +51,7 @@ func TestMarshalingNebulaCertificate(t *testing.T) {
 	assert.Nil(t, err)
 	//t.Log("Cert size:", len(b))
 
-	nc2, err := unmarshalCertificateV1(b, true)
+	nc2, err := unmarshalCertificateV1(b, nil)
 	assert.Nil(t, err)
 
 	assert.Equal(t, nc.signature, nc2.Signature())
@@ -534,7 +534,7 @@ func TestNebulaCertificate_Copy(t *testing.T) {
 func TestUnmarshalNebulaCertificate(t *testing.T) {
 	// Test that we don't panic with an invalid certificate (#332)
 	data := []byte("\x98\x00\x00")
-	_, err := unmarshalCertificateV1(data, true)
+	_, err := unmarshalCertificateV1(data, nil)
 	assert.EqualError(t, err, "encoded Details was nil")
 }