Unmarshall wrapped into string integers as string (#1470)

services/typeddata/hash.go

@@ -17,6 +17,8 @@ import (
 var (
 	bytes32Type, _ = abi.NewType("bytes32", nil)
 	int256Type, _  = abi.NewType("int256", nil)
+
+	errNotInteger = errors.New("not an integer")
 )
 
 // ValidateAndHash generates a hash of TypedData and verifies that chainId in the typed data matches currently selected chain.
@@ -171,11 +173,21 @@ func toFixedBytes(f Field, data json.RawMessage) (rst [32]byte, typ abi.Type, er
 }
 
 func toInt(f Field, data json.RawMessage) (val *big.Int, typ abi.Type, err error) {
-	var rst big.Int
-	if err = json.Unmarshal(data, &rst); err != nil {
-		return
+	val = new(big.Int)
+	if err = json.Unmarshal(data, &val); err != nil {
+		var buf string
+		err = json.Unmarshal(data, &buf)
+		if err != nil {
+			return
+		}
+		var ok bool
+		val, ok = val.SetString(buf, 0)
+		if !ok {
+			err = errNotInteger
+			return
+		}
 	}
-	return &rst, int256Type, nil
+	return val, int256Type, nil
 }
 
 func toAddress(f Field, data json.RawMessage) (rst common.Address, err error) {

services/typeddata/hash_test.go

@@ -2,6 +2,7 @@ package typeddata
 
 import (
 	"encoding/json"
+	"fmt"
 	"math/big"
 	"testing"
 
@@ -271,3 +272,39 @@ func TestEncodeDataErrors(t *testing.T) {
 		})
 	}
 }
+
+func TestEncodeInt(t *testing.T) {
+	example := new(big.Int).Exp(big.NewInt(2), big.NewInt(255), nil)
+	for _, tc := range []struct {
+		description string
+		data        []byte
+		expected    *big.Int
+		err         error
+	}{
+		{
+			description: "AsString",
+			data:        []byte(example.String()),
+			expected:    example,
+		},
+		{
+			description: "WrappedIntoString",
+			data:        []byte(fmt.Sprintf("\"%s\"", example.String())),
+			expected:    example,
+		},
+		{
+			description: "NotAnInteger",
+			data:        []byte("\"xzy\""),
+			err:         errNotInteger,
+		},
+	} {
+		t.Run(tc.description, func(t *testing.T) {
+			rst, _, err := toInt(Field{}, tc.data)
+			if tc.err == nil {
+				require.NoError(t, err)
+				require.Equal(t, tc.expected, rst)
+			} else {
+				require.EqualError(t, err, tc.err.Error())
+			}
+		})
+	}
+}