Fuzz message

I had to move Verify function into separate file to tag it as `cgo` only
build. go-fuzz doesn't work with cgo.

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

.gitignore

@@ -7,3 +7,7 @@
 **/*.a
 **/*.pc
 build/.*
+/vendor
+
+*-fuzz.zip
+/chain/types/work_msg/

chain/types/message_fuzz.go

@@ -0,0 +1,30 @@
+//+build gofuzz
+
+package types
+
+import "bytes"
+
+func FuzzMessage(data []byte) int {
+	var msg Message
+	err := msg.UnmarshalCBOR(bytes.NewReader(data))
+	if err != nil {
+		return 0
+	}
+	reData, err := msg.Serialize()
+	if err != nil {
+		panic(err)
+	}
+	var msg2 Message
+	err = msg2.UnmarshalCBOR(bytes.NewReader(data))
+	if err != nil {
+		panic(err)
+	}
+	reData2, err := msg.Serialize()
+	if err != nil {
+		panic(err)
+	}
+	if !bytes.Equal(reData, reData2) {
+		panic("reencoding not equal")
+	}
+	return 1
+}

chain/types/signature.go

@@ -6,11 +6,7 @@ import (
 	"fmt"
 	"io"
 
-	bls "github.com/filecoin-project/go-bls-sigs"
-	"github.com/filecoin-project/go-lotus/chain/address"
-	"github.com/filecoin-project/go-lotus/lib/crypto"
 	cbor "github.com/ipfs/go-ipld-cbor"
-	"github.com/minio/blake2b-simd"
 	"github.com/polydawn/refmt/obj/atlas"
 	cbg "github.com/whyrusleeping/cbor-gen"
 )
@@ -70,49 +66,6 @@ func SignatureFromBytes(x []byte) (Signature, error) {
 	}, nil
 }
 
-func (s *Signature) Verify(addr address.Address, msg []byte) error {
-	if addr.Protocol() == address.ID {
-		return fmt.Errorf("must resolve ID addresses before using them to verify a signature")
-	}
-	b2sum := blake2b.Sum256(msg)
-
-	switch s.Type {
-	case KTSecp256k1:
-		pubk, err := crypto.EcRecover(b2sum[:], s.Data)
-		if err != nil {
-			return err
-		}
-
-		maybeaddr, err := address.NewSecp256k1Address(pubk)
-		if err != nil {
-			return err
-		}
-
-		if addr != maybeaddr {
-			return fmt.Errorf("signature did not match")
-		}
-
-		return nil
-	case KTBLS:
-		digests := []bls.Digest{bls.Hash(bls.Message(msg))}
-
-		var pubk bls.PublicKey
-		copy(pubk[:], addr.Payload())
-		pubkeys := []bls.PublicKey{pubk}
-
-		var sig bls.Signature
-		copy(sig[:], s.Data)
-
-		if !bls.Verify(sig, digests, pubkeys) {
-			return fmt.Errorf("bls signature failed to verify")
-		}
-
-		return nil
-	default:
-		return fmt.Errorf("cannot verify signature of unsupported type: %s", s.Type)
-	}
-}
-
 func (s *Signature) TypeCode() int {
 	switch s.Type {
 	case KTSecp256k1:

chain/types/signature_cgo.go

@@ -0,0 +1,55 @@
+//+build cgo
+
+package types
+
+import (
+	"fmt"
+
+	bls "github.com/filecoin-project/go-bls-sigs"
+	"github.com/filecoin-project/go-lotus/chain/address"
+	"github.com/filecoin-project/go-lotus/lib/crypto"
+	"github.com/minio/blake2b-simd"
+)
+
+func (s *Signature) Verify(addr address.Address, msg []byte) error {
+	if addr.Protocol() == address.ID {
+		return fmt.Errorf("must resolve ID addresses before using them to verify a signature")
+	}
+	b2sum := blake2b.Sum256(msg)
+
+	switch s.Type {
+	case KTSecp256k1:
+		pubk, err := crypto.EcRecover(b2sum[:], s.Data)
+		if err != nil {
+			return err
+		}
+
+		maybeaddr, err := address.NewSecp256k1Address(pubk)
+		if err != nil {
+			return err
+		}
+
+		if addr != maybeaddr {
+			return fmt.Errorf("signature did not match")
+		}
+
+		return nil
+	case KTBLS:
+		digests := []bls.Digest{bls.Hash(bls.Message(msg))}
+
+		var pubk bls.PublicKey
+		copy(pubk[:], addr.Payload())
+		pubkeys := []bls.PublicKey{pubk}
+
+		var sig bls.Signature
+		copy(sig[:], s.Data)
+
+		if !bls.Verify(sig, digests, pubkeys) {
+			return fmt.Errorf("bls signature failed to verify")
+		}
+
+		return nil
+	default:
+		return fmt.Errorf("cannot verify signature of unsupported type: %s", s.Type)
+	}
+}