core/types: fix panic on invalid signature length #33647 (#1979)

Replace panic with error return in decodeSignature to prevent crashes on
invalid inputs, and update callers to propagate the error.

Co-authored-by: DeFi Junkie <deffie.jnkiee@gmail.com>

core/types/transaction_signing.go

@@ -217,7 +217,10 @@ func (s pragueSigner) SignatureValues(tx *Transaction, sig []byte) (R, S, V *big
 	if txdata.ChainID.Sign() != 0 && txdata.ChainID.CmpBig(s.chainId) != 0 {
 		return nil, nil, nil, fmt.Errorf("%w: have %d want %d", ErrInvalidChainId, txdata.ChainID, s.chainId)
 	}
-	R, S, _ = decodeSignature(sig)
+	R, S, _, err = decodeSignature(sig)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 	V = big.NewInt(int64(sig[64]))
 	return R, S, V, nil
 }
@@ -284,7 +287,10 @@ func (s londonSigner) SignatureValues(tx *Transaction, sig []byte) (R, S, V *big
 	if txdata.ChainID.Sign() != 0 && txdata.ChainID.Cmp(s.chainId) != 0 {
 		return nil, nil, nil, ErrInvalidChainId
 	}
-	R, S, _ = decodeSignature(sig)
+	R, S, _, err = decodeSignature(sig)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 	V = big.NewInt(int64(sig[64]))
 	return R, S, V, nil
 }
@@ -355,7 +361,10 @@ func (s eip2930Signer) SignatureValues(tx *Transaction, sig []byte) (R, S, V *bi
 		if txdata.ChainID.Sign() != 0 && txdata.ChainID.Cmp(s.chainId) != 0 {
 			return nil, nil, nil, ErrInvalidChainId
 		}
-		R, S, _ = decodeSignature(sig)
+		R, S, _, err = decodeSignature(sig)
+		if err != nil {
+			return nil, nil, nil, err
+		}
 		V = big.NewInt(int64(sig[64]))
 	default:
 		return nil, nil, nil, ErrTxTypeNotSupported
@@ -440,7 +449,10 @@ func (s EIP155Signer) SignatureValues(tx *Transaction, sig []byte) (R, S, V *big
 	if tx.Type() != LegacyTxType {
 		return nil, nil, nil, ErrTxTypeNotSupported
 	}
-	R, S, V = decodeSignature(sig)
+	R, S, V, err = decodeSignature(sig)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 	if s.chainId.Sign() != 0 {
 		V = big.NewInt(int64(sig[64] + 35))
 		V.Add(V, s.chainIdMul)
@@ -514,8 +526,8 @@ func (fs FrontierSigner) SignatureValues(tx *Transaction, sig []byte) (r, s, v *
 	if tx.Type() != LegacyTxType {
 		return nil, nil, nil, ErrTxTypeNotSupported
 	}
-	r, s, v = decodeSignature(sig)
+	r, s, v, err = decodeSignature(sig)
-	return r, s, v, nil
+	return r, s, v, err
 }
 
 // Hash returns the hash to be signed by the sender.
@@ -531,14 +543,14 @@ func (fs FrontierSigner) Hash(tx *Transaction) common.Hash {
 	})
 }
 
-func decodeSignature(sig []byte) (r, s, v *big.Int) {
+func decodeSignature(sig []byte) (r, s, v *big.Int, err error) {
 	if len(sig) != crypto.SignatureLength {
-		panic(fmt.Sprintf("wrong size for signature: got %d, want %d", len(sig), crypto.SignatureLength))
+		return nil, nil, nil, fmt.Errorf("wrong size for signature: got %d, want %d", len(sig), crypto.SignatureLength)
 	}
 	r = new(big.Int).SetBytes(sig[:32])
 	s = new(big.Int).SetBytes(sig[32:64])
 	v = new(big.Int).SetBytes([]byte{sig[64] + 27})
-	return r, s, v
+	return r, s, v, nil
 }
 
 func recoverPlain(sighash common.Hash, R, S, Vb *big.Int, homestead bool) (common.Address, error) {

core/types/transaction_signing_test.go

@@ -135,3 +135,28 @@ func TestChainId(t *testing.T) {
 		t.Error("expected no error")
 	}
 }
+
+func TestSignatureValuesError(t *testing.T) {
+	// 1. Setup a valid transaction
+	tx := NewTransaction(0, common.Address{}, big.NewInt(0), 0, big.NewInt(0), nil)
+	signer := HomesteadSigner{}
+
+	// 2. Call WithSignature with invalid length sig (not 65 bytes)
+	invalidSig := make([]byte, 64)
+
+	func() {
+		defer func() {
+			if r := recover(); r != nil {
+				t.Fatalf("Panicked for invalid signature length, expected error: %v", r)
+			}
+		}()
+		_, err := tx.WithSignature(signer, invalidSig)
+		if err == nil {
+			t.Fatal("Expected error for invalid signature length, got nil")
+		} else {
+			// This is just a sanity check to ensure we got an error,
+			// the exact error message is verified in unit tests elsewhere if needed.
+			t.Logf("Got expected error: %v", err)
+		}
+	}()
+}

core/types/tx_setcode.go

@@ -94,7 +94,10 @@ func SignSetCode(prv *ecdsa.PrivateKey, auth SetCodeAuthorization) (SetCodeAutho
 	if err != nil {
 		return SetCodeAuthorization{}, err
 	}
-	r, s, _ := decodeSignature(sig)
+	r, s, _, err := decodeSignature(sig)
+	if err != nil {
+		return SetCodeAuthorization{}, err
+	}
 	return SetCodeAuthorization{
 		ChainID: auth.ChainID,
 		Address: auth.Address,