make envelope fields private & validate on unmarshal

crypto/envelope.go

@@ -16,14 +16,13 @@ import (
 type SignedEnvelope struct {
 
 	// The public key that can be used to verify the signature and derive the peer id of the signer.
-	PublicKey PubKey
+	publicKey PubKey
 
 	// A binary identifier that indicates what kind of data is contained in the payload.
 	// TODO(yusef): enforce multicodec prefix
-	PayloadType []byte
+	payloadType []byte
 
-	// The envelope payload. This is private to discourage accessing the payload without verifying the signature.
-	// To access, use the Open method.
+	// The envelope payload.
 	payload []byte
 
 	// The signature of the domain string, type hint, and payload.
@@ -31,6 +30,7 @@ type SignedEnvelope struct {
 }
 
 var errEmptyDomain = errors.New("envelope domain must not be empty")
+var errInvalidSignature = errors.New("invalid signature or incorrect domain")
 
 // MakeEnvelope constructs a new SignedEnvelope using the given privateKey.
 //
@@ -38,27 +38,42 @@ var errEmptyDomain = errors.New("envelope domain must not be empty")
 // and must be supplied when verifying the signature.
 //
 // The 'payloadType' field indicates what kind of data is contained and may be empty.
-func MakeEnvelope(privateKey PrivKey, domain string, payloadType []byte, contents []byte) (*SignedEnvelope, error) {
+func MakeEnvelope(privateKey PrivKey, domain string, payloadType []byte, payload []byte) (*SignedEnvelope, error) {
 	if len(domain) == 0 {
 		return nil, errEmptyDomain
 	}
-	toSign := makeSigBuffer(domain, payloadType, contents)
+	toSign := makeSigBuffer(domain, payloadType, payload)
 	sig, err := privateKey.Sign(toSign)
 	if err != nil {
 		return nil, err
 	}
 
 	return &SignedEnvelope{
-		PublicKey:   privateKey.GetPublic(),
-		PayloadType: payloadType,
-		payload:     contents,
+		publicKey:   privateKey.GetPublic(),
+		payloadType: payloadType,
+		payload:     payload,
 		signature:   sig,
 	}, nil
 }
 
-// UnmarshalEnvelope converts a serialized protobuf representation of an envelope
-// into a SignedEnvelope struct.
-func UnmarshalEnvelope(serializedEnvelope []byte) (*SignedEnvelope, error) {
+// OpenEnvelope unmarshals a serialized SignedEnvelope, validating its signature
+// using the provided 'domain' string.
+func OpenEnvelope(envelopeBytes []byte, domain string) (*SignedEnvelope, error) {
+	e, err := UnmarshalEnvelopeWithoutValidating(envelopeBytes)
+	if err != nil {
+		return nil, err
+	}
+	err = e.validate(domain)
+	if err != nil {
+		return nil, err
+	}
+	return e, nil
+}
+
+// UnmarshalEnvelopeWithoutValidating unmarshals a serialized SignedEnvelope protobuf message,
+// without validating its contents. Should not be used unless you have a very good reason
+// (e.g. testing)!
+func UnmarshalEnvelopeWithoutValidating(serializedEnvelope []byte) (*SignedEnvelope, error) {
 	e := pb.SignedEnvelope{}
 	if err := proto.Unmarshal(serializedEnvelope, &e); err != nil {
 		return nil, err
@@ -68,57 +83,63 @@ func UnmarshalEnvelope(serializedEnvelope []byte) (*SignedEnvelope, error) {
 		return nil, err
 	}
 	return &SignedEnvelope{
-		PublicKey:   key,
-		PayloadType: e.PayloadType,
+		publicKey:   key,
+		payloadType: e.PayloadType,
 		payload:     e.Payload,
 		signature:   e.Signature,
 	}, nil
 }
 
-// Validate returns true if the envelope signature is valid for the given 'domain',
-// or false if it is invalid. May return an error if signature validation fails.
-func (e *SignedEnvelope) Validate(domain string) (bool, error) {
-	toVerify := makeSigBuffer(domain, e.PayloadType, e.payload)
-	return e.PublicKey.Verify(toVerify, e.signature)
+// PublicKey returns the public key that can be used to verify the signature and derive the peer id of the signer.
+func (e *SignedEnvelope) PublicKey() PubKey {
+	return e.publicKey
+}
+
+// PayloadType returns a binary identifier that indicates what kind of data is contained in the payload.
+func (e *SignedEnvelope) PayloadType() []byte {
+	return e.payloadType
+}
+
+// Payload returns the binary payload of a SignedEnvelope.
+func (e *SignedEnvelope) Payload() []byte {
+	return e.payload
 }
 
-// Marshal returns a []byte containing a serialized protobuf representation of
-// the SignedEnvelope.
 func (e *SignedEnvelope) Marshal() ([]byte, error) {
-	key, err := PublicKeyToProto(e.PublicKey)
+	key, err := PublicKeyToProto(e.publicKey)
 	if err != nil {
 		return nil, err
 	}
 	msg := pb.SignedEnvelope{
 		PublicKey:   key,
-		PayloadType: e.PayloadType,
+		PayloadType: e.payloadType,
 		Payload:     e.payload,
 		Signature:   e.signature,
 	}
 	return proto.Marshal(&msg)
 }
 
-// Open validates the signature (within the given 'domain') and returns
-// the payload of the envelope. Will fail with an error if the signature
-// is invalid.
-func (e *SignedEnvelope) Open(domain string) ([]byte, error) {
-	valid, err := e.Validate(domain)
-	if err != nil {
-		return nil, err
-	}
-	if !valid {
-		return nil, errors.New("invalid signature or incorrect domain")
-	}
-	return e.payload, nil
-}
-
 func (e *SignedEnvelope) Equals(other *SignedEnvelope) bool {
-	return e.PublicKey.Equals(other.PublicKey) &&
-		bytes.Compare(e.PayloadType, other.PayloadType) == 0 &&
+	return e.publicKey.Equals(other.publicKey) &&
+		bytes.Compare(e.payloadType, other.payloadType) == 0 &&
 		bytes.Compare(e.payload, other.payload) == 0 &&
 		bytes.Compare(e.signature, other.signature) == 0
 }
 
+// validate returns true if the envelope signature is valid for the given 'domain',
+// or false if it is invalid. May return an error if signature validation fails.
+func (e *SignedEnvelope) validate(domain string) error {
+	toVerify := makeSigBuffer(domain, e.payloadType, e.payload)
+	valid, err := e.publicKey.Verify(toVerify, e.signature)
+	if err != nil {
+		return err
+	}
+	if !valid {
+		return errInvalidSignature
+	}
+	return nil
+}
+
 // makeSigBuffer is a helper function that prepares a buffer to sign or verify.
 func makeSigBuffer(domain string, typeHint []byte, content []byte) []byte {
 	b := bytes.Buffer{}

crypto/envelope_test.go

@@ -2,7 +2,8 @@ package crypto_test
 
 import (
 	"bytes"
-	"github.com/gogo/protobuf/proto"
+	"github.com/golang/protobuf/proto"
+
 	. "github.com/libp2p/go-libp2p-core/crypto"
 	pb "github.com/libp2p/go-libp2p-core/crypto/pb"
 	"github.com/libp2p/go-libp2p-core/test"
@@ -23,39 +24,27 @@ func TestEnvelopeHappyPath(t *testing.T) {
 		t.Errorf("error constructing envelope: %v", err)
 	}
 
-	if !envelope.PublicKey.Equals(pub) {
+	if !envelope.PublicKey().Equals(pub) {
 		t.Error("envelope has unexpected public key")
 	}
 
-	if bytes.Compare(payloadType, envelope.PayloadType) != 0 {
+	if bytes.Compare(payloadType, envelope.PayloadType()) != 0 {
 		t.Error("PayloadType does not match payloadType used to construct envelope")
 	}
 
-	valid, err := envelope.Validate(domain)
-	if err != nil {
-		t.Errorf("error validating envelope: %v", err)
-	}
-	if !valid {
-		t.Error("envelope should be valid, but Valid returns false")
-	}
-
-	c, err := envelope.Open(domain)
-	if err != nil {
-		t.Errorf("error opening envelope: %v", err)
-	}
-	if bytes.Compare(c, payload) != 0 {
-		t.Error("payload of envelope do not match input")
-	}
-
 	serialized, err := envelope.Marshal()
 	if err != nil {
 		t.Errorf("error serializing envelope: %v", err)
 	}
-	deserialized, err := UnmarshalEnvelope(serialized)
+	deserialized, err := OpenEnvelope(serialized, domain)
 	if err != nil {
 		t.Errorf("error deserializing envelope: %v", err)
 	}
 
+	if bytes.Compare(deserialized.Payload(), payload) != 0 {
+		t.Error("payload of envelope does not match input")
+	}
+
 	if !envelope.Equals(deserialized) {
 		t.Error("round-trip serde results in unequal envelope structures")
 	}
@@ -73,13 +62,11 @@ func TestEnvelopeValidateFailsForDifferentDomain(t *testing.T) {
 	if err != nil {
 		t.Errorf("error constructing envelope: %v", err)
 	}
-
-	valid, err := envelope.Validate("other-domain")
-	if err != nil {
-		t.Errorf("error validating envelope: %v", err)
-	}
-	if valid {
-		t.Error("envelope should be invalid, but Valid returns true")
+	serialized, err := envelope.Marshal()
+	// try to open our modified envelope
+	_, err = OpenEnvelope(serialized, "wrong-domain")
+	if err == nil {
+		t.Error("should not be able to open envelope with incorrect domain")
 	}
 }
 
@@ -95,13 +82,13 @@ func TestEnvelopeValidateFailsIfTypeHintIsAltered(t *testing.T) {
 	if err != nil {
 		t.Errorf("error constructing envelope: %v", err)
 	}
-	envelope.PayloadType = []byte("foo")
-	valid, err := envelope.Validate("other-domain")
-	if err != nil {
-		t.Errorf("error validating envelope: %v", err)
-	}
-	if valid {
-		t.Error("envelope should be invalid, but Valid returns true")
+	serialized := alterMessageAndMarshal(t, envelope, func(msg *pb.SignedEnvelope) {
+		msg.PayloadType = []byte("foo")
+	})
+	// try to open our modified envelope
+	_, err = OpenEnvelope(serialized, domain)
+	if err == nil {
+		t.Error("should not be able to open envelope with modified payloadType")
 	}
 }
 
@@ -118,33 +105,35 @@ func TestEnvelopeValidateFailsIfContentsAreAltered(t *testing.T) {
 		t.Errorf("error constructing envelope: %v", err)
 	}
 
-	// since the payload field is private, we'll serialize and alter the
-	// serialized protobuf
+	serialized := alterMessageAndMarshal(t, envelope, func(msg *pb.SignedEnvelope) {
+		msg.Payload = []byte("totally legit, trust me")
+	})
+	// try to open our modified envelope
+	_, err = OpenEnvelope(serialized, domain)
+	if err == nil {
+		t.Error("should not be able to open envelope with modified payload")
+	}
+}
+
+// Since we're outside of the crypto package (to avoid import cycles with test package),
+// we can't alter the fields in a SignedEnvelope directly. This helper marshals
+// the envelope to a protobuf and calls the alterMsg function, which should
+// alter the protobuf message.
+// Returns the serialized altered protobuf message.
+func alterMessageAndMarshal(t *testing.T, envelope *SignedEnvelope, alterMsg func(*pb.SignedEnvelope)) []byte {
 	serialized, err := envelope.Marshal()
 	if err != nil {
-		t.Errorf("error serializing envelope: %v", err)
+		t.Errorf("error marshaling envelope: %v", err)
 	}
-
 	msg := pb.SignedEnvelope{}
 	err = proto.Unmarshal(serialized, &msg)
 	if err != nil {
-		t.Errorf("error deserializing envelope: %v", err)
+		t.Errorf("error unmarshaling envelope: %v", err)
 	}
-	msg.Payload = []byte("totally legit, trust me")
-	serialized, err = proto.Marshal(&msg)
-
-	// unmarshal our altered envelope
-	deserialized, err := UnmarshalEnvelope(serialized)
+	alterMsg(&msg)
+	serialized, err = msg.Marshal()
 	if err != nil {
-		t.Errorf("error deserializing envelope: %v", err)
-	}
-
-	// verify that it's now invalid
-	valid, err := deserialized.Validate(domain)
-	if err != nil {
-		t.Errorf("error validating envelope: %v", err)
-	}
-	if valid {
-		t.Error("envelope should be invalid, but Valid returns true")
+		t.Errorf("error marshaling envelope: %v", err)
 	}
+	return serialized
 }

peerstore/peerstore.go

@@ -97,8 +97,8 @@ type AddrBook interface {
 	AddAddrs(p peer.ID, addrs []ma.Multiaddr, ttl time.Duration)
 
 	// AddCertifiedAddrs adds addresses from a routing.RoutingState record
-	// contained in the given SignedEnvelope.
-	AddCertifiedAddrs(envelope *ic.SignedEnvelope, ttl time.Duration) error
+	// contained in a serialized SignedEnvelope.
+	AddCertifiedAddrs(envelopeBytes []byte, ttl time.Duration) error
 
 	// SetAddr calls mgr.SetAddrs(p, addr, ttl)
 	SetAddr(p peer.ID, addr ma.Multiaddr, ttl time.Duration)
@@ -130,9 +130,17 @@ type AddrBook interface {
 	// PeersWithAddrs returns all of the peer IDs stored in the AddrBook
 	PeersWithAddrs() peer.IDSlice
 
-	// SignedRoutingState returns a SignedEnvelope containing a RoutingState
-	// record, if one exists for the given peer.
-	SignedRoutingState(p peer.ID) *ic.SignedEnvelope
+	// SignedRoutingState returns a signed RoutingState record for the
+	// given peer id, if one exists in the peerstore. The record is
+	// returned as a byte slice containing a serialized SignedEnvelope.
+	// Returns nil if no routing state exists for the peer.
+	SignedRoutingState(p peer.ID) []byte
+
+	// SignedRoutingStates returns signed RoutingState records for each of
+	// the given peer ids, if one exists in the peerstore.
+	// Returns a map of peer ids to serialized SignedEnvelope messages. If
+	// no routing state exists for a peer, their map entry will be nil.
+	SignedRoutingStates(peers ...peer.ID) map[peer.ID][]byte
 }
 
 // KeyBook tracks the keys of Peers.

routing/state.go

@@ -75,16 +75,19 @@ func UnmarshalRoutingState(serialized []byte) (*RoutingState, error) {
 // RoutingStateFromEnvelope unwraps a peer RoutingState record from a SignedEnvelope.
 // This method will fail if the signature is invalid, or if the record
 // belongs to a peer other than the one that signed the envelope.
-func RoutingStateFromEnvelope(envelope *crypto.SignedEnvelope) (*RoutingState, error) {
-	msgBytes, err := envelope.Open(StateEnvelopeDomain)
+func RoutingStateFromEnvelope(envelopeBytes []byte) (*RoutingState, error) {
+	envelope, err := crypto.OpenEnvelope(envelopeBytes, StateEnvelopeDomain)
 	if err != nil {
 		return nil, err
 	}
-	state, err := UnmarshalRoutingState(msgBytes)
+	if bytes.Compare(envelope.PayloadType(), StateEnvelopePayloadType) != 0 {
+		return nil, errors.New("unexpected envelope payload type")
+	}
+	state, err := UnmarshalRoutingState(envelope.Payload())
 	if err != nil {
 		return nil, err
 	}
-	if !state.PeerID.MatchesPublicKey(envelope.PublicKey) {
+	if !state.PeerID.MatchesPublicKey(envelope.PublicKey()) {
 		return nil, errors.New("peer id in routing state record does not match signing key")
 	}
 	return state, nil