Do not validate signature on the attestation package

crypto/bls/bls.go

@@ -24,6 +24,13 @@ func PublicKeyFromBytes(pubKey []byte) (PublicKey, error) {
 	return blst.PublicKeyFromBytes(pubKey)
 }
 
+// SignatureFromBytesNoValidation creates a BLS signature from a LittleEndian byte slice.
+// It does not check validity of the signature, use only when the byte slice has
+// already been verified
+func SignatureFromBytesNoValidation(sig []byte) (Signature, error) {
+	return blst.SignatureFromBytesNoValidation(sig)
+}
+
 // SignatureFromBytes creates a BLS signature from a LittleEndian byte slice.
 func SignatureFromBytes(sig []byte) (Signature, error) {
 	return blst.SignatureFromBytes(sig)

crypto/bls/blst/signature.go

@@ -24,15 +24,35 @@ type Signature struct {
 	s *blstSignature
 }
 
-// SignatureFromBytes creates a BLS signature from a LittleEndian byte slice.
-func SignatureFromBytes(sig []byte) (common.Signature, error) {
+// signatureFromBytesNoValidation creates a BLS signature from a LittleEndian
+// byte slice. It does not validate that the signature is in the BLS group
+func signatureFromBytesNoValidation(sig []byte) (*blstSignature, error) {
 	if len(sig) != fieldparams.BLSSignatureLength {
 		return nil, fmt.Errorf("signature must be %d bytes", fieldparams.BLSSignatureLength)
 	}
 	signature := new(blstSignature).Uncompress(sig)
 	if signature == nil {
 		return nil, errors.New("could not unmarshal bytes into signature")
 	}
+	return signature, nil
+}
+
+// SignatureFromBytesNoValidation creates a BLS signature from a LittleEndian
+// byte slice. It does not validate that the signature is in the BLS group
+func SignatureFromBytesNoValidation(sig []byte) (common.Signature, error) {
+	signature, err := signatureFromBytesNoValidation(sig)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not create signature from byte slice")
+	}
+	return &Signature{s: signature}, nil
+}
+
+// SignatureFromBytes creates a BLS signature from a LittleEndian byte slice.
+func SignatureFromBytes(sig []byte) (common.Signature, error) {
+	signature, err := signatureFromBytesNoValidation(sig)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not create signature from byte slice")
+	}
 	// Group check signature. Do not check for infinity since an aggregated signature
 	// could be infinite.
 	if !signature.SigValidate(false) {

proto/prysm/v1alpha1/attestation/aggregation/attestations/attestations.go

@@ -15,7 +15,7 @@ type attList []*ethpb.Attestation
 // significantly more expensive than the inner logic of AggregateAttestations so they must be
 // substituted for benchmarks which analyze AggregateAttestations.
 var aggregateSignatures = bls.AggregateSignatures
-var signatureFromBytes = bls.SignatureFromBytes
+var signatureFromBytes = bls.SignatureFromBytesNoValidation
 
 var _ = logrus.WithField("prefix", "aggregation.attestations")