signer/core, signer/core/apitypes: fix encoding of bytes nested within array

signer/core/apitypes/types.go

@@ -498,10 +498,19 @@ func (typedData *TypedData) encodeArrayValue(encValue interface{}, encType strin
 
 	arrayBuffer := new(bytes.Buffer)
 	parsedType := strings.Split(encType, "[")[0]
+
 	for _, item := range arrayValue {
 		if reflect.TypeOf(item).Kind() == reflect.Slice ||
 			reflect.TypeOf(item).Kind() == reflect.Array {
-			encodedData, err := typedData.encodeArrayValue(item, parsedType, depth+1)
+			var (
+				encodedData hexutil.Bytes
+				err         error
+			)
+			if reflect.TypeOf(item).Elem().Kind() == reflect.Uint8 {
+				encodedData, err = typedData.EncodePrimitiveValue(parsedType, item, depth+1)
+			} else {
+				encodedData, err = typedData.encodeArrayValue(item, parsedType, depth+1)
+			}
 			if err != nil {
 				return nil, err
 			}

signer/core/signed_data_recursive_array_test.go

@@ -0,0 +1,60 @@
+package core
+
+import (
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/signer/core/apitypes"
+	"testing"
+)
+
+var typesStandard = apitypes.Types{
+	"EIP712Domain": {
+		{
+			Name: "name",
+			Type: "string",
+		},
+		{
+			Name: "version",
+			Type: "string",
+		},
+		{
+			Name: "chainId",
+			Type: "uint256",
+		},
+		{
+			Name: "verifyingContract",
+			Type: "address",
+		},
+	},
+	"Val": {
+		{
+			Name: "field",
+			Type: "bytes[][]",
+		},
+	},
+}
+
+var messageStandard = map[string]interface{}{
+	"field": [][][]byte{{{1}, {2}}, {{3}, {4}}},
+}
+
+var domainStandard = apitypes.TypedDataDomain{
+	Name:              "Ether Mail",
+	Version:           "1",
+	ChainId:           math.NewHexOrDecimal256(1),
+	VerifyingContract: "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
+	Salt:              "",
+}
+
+var typedData = apitypes.TypedData{
+	Types:       typesStandard,
+	PrimaryType: "Val",
+	Domain:      domainStandard,
+	Message:     messageStandard,
+}
+
+func TestEncodeDataRecursiveBytes(t *testing.T) {
+	_, err := typedData.EncodeData(typedData.PrimaryType, typedData.Message, 0)
+	if err != nil {
+		t.Fatalf("got err %v", err)
+	}
+}