signer/core: extended support for EIP-712 array types (#30620)

This change updates the EIP-712 implementation to resolve [#30619](https://github.com/ethereum/go-ethereum/issues/30619).

The test cases have been repurposed from the ethers.js [repository](https://github.com/ethers-io/ethers.js/blob/main/testcases/typed-data.json.gz), but have been updated to remove tests that don't have a valid domain separator; EIP-712 messages without a domain separator are not supported by geth.

---------

Co-authored-by: Martin Holst Swende <martin@swende.se>

signer/core/apitypes/signed_data_internal_test.go

@@ -18,12 +18,18 @@ package apitypes
 
 import (
 	"bytes"
+	"encoding/json"
+	"fmt"
 	"math/big"
+	"os"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestBytesPadding(t *testing.T) {
@@ -244,45 +250,42 @@ func TestConvertAddressDataToSlice(t *testing.T) {
 func TestTypedDataArrayValidate(t *testing.T) {
 	t.Parallel()
 
-	typedData := TypedData{
-		Types: Types{
-			"BulkOrder": []Type{
-				// Should be able to accept fixed size arrays
-				{Name: "tree", Type: "OrderComponents[2][2]"},
-			},
-			"OrderComponents": []Type{
-				{Name: "offerer", Type: "address"},
-				{Name: "amount", Type: "uint8"},
-			},
-			"EIP712Domain": []Type{
-				{Name: "name", Type: "string"},
-				{Name: "version", Type: "string"},
-				{Name: "chainId", Type: "uint8"},
-				{Name: "verifyingContract", Type: "address"},
-			},
-		},
-		PrimaryType: "BulkOrder",
-		Domain: TypedDataDomain{
-			VerifyingContract: "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
-		},
-		Message: TypedDataMessage{},
+	type testDataInput struct {
+		Name        string           `json:"name"`
+		Domain      TypedDataDomain  `json:"domain"`
+		PrimaryType string           `json:"primaryType"`
+		Types       Types            `json:"types"`
+		Message     TypedDataMessage `json:"data"`
+		Digest      string           `json:"digest"`
 	}
+	fc, err := os.ReadFile("./testdata/typed-data.json")
+	require.NoError(t, err, "error reading test data file")
 
-	if err := typedData.validate(); err != nil {
-		t.Errorf("expected typed data to pass validation, got: %v", err)
-	}
+	var tests []testDataInput
+	err = json.Unmarshal(fc, &tests)
+	require.NoError(t, err, "error unmarshalling test data file contents")
 
-	// Should be able to accept dynamic arrays
-	typedData.Types["BulkOrder"][0].Type = "OrderComponents[]"
+	for _, tc := range tests {
+		t.Run(tc.Name, func(t *testing.T) {
+			t.Parallel()
 
-	if err := typedData.validate(); err != nil {
-		t.Errorf("expected typed data to pass validation, got: %v", err)
-	}
+			td := TypedData{
+				Types:       tc.Types,
+				PrimaryType: tc.PrimaryType,
+				Domain:      tc.Domain,
+				Message:     tc.Message,
+			}
 
-	// Should be able to accept standard types
-	typedData.Types["BulkOrder"][0].Type = "OrderComponents"
+			domainSeparator, tErr := td.HashStruct("EIP712Domain", td.Domain.Map())
+			assert.NoError(t, tErr, "failed to hash domain separator: %v", tErr)
 
-	if err := typedData.validate(); err != nil {
-		t.Errorf("expected typed data to pass validation, got: %v", err)
+			messageHash, tErr := td.HashStruct(td.PrimaryType, td.Message)
+			assert.NoError(t, tErr, "failed to hash message: %v", tErr)
+
+			digest := crypto.Keccak256Hash([]byte(fmt.Sprintf("%s%s%s", "\x19\x01", string(domainSeparator), string(messageHash))))
+			assert.Equal(t, tc.Digest, digest.String(), "digest doesn't not match")
+
+			assert.NoError(t, td.validate(), "validation failed", tErr)
+		})
 	}
 }

signer/core/apitypes/types.go

@@ -325,18 +325,17 @@ type Type struct {
 	Type string `json:"type"`
 }
 
+// isArray returns true if the type is a fixed or variable sized array.
+// This method may return false positives, in case the Type is not a valid
+// expression, e.g. "fooo[[[[".
 func (t *Type) isArray() bool {
-	return strings.HasSuffix(t.Type, "[]")
+	return strings.IndexByte(t.Type, '[') > 0
 }
 
-// typeName returns the canonical name of the type. If the type is 'Person[]', then
+// typeName returns the canonical name of the type. If the type is 'Person[]' or 'Person[2]', then
 // this method returns 'Person'
 func (t *Type) typeName() string {
-	if strings.Contains(t.Type, "[") {
-		re := regexp.MustCompile(`\[\d*\]`)
-		return re.ReplaceAllString(t.Type, "")
-	}
-	return t.Type
+	return strings.Split(t.Type, "[")[0]
 }
 
 type Types map[string][]Type
@@ -387,7 +386,7 @@ func (typedData *TypedData) HashStruct(primaryType string, data TypedDataMessage
 
 // Dependencies returns an array of custom types ordered by their hierarchical reference tree
 func (typedData *TypedData) Dependencies(primaryType string, found []string) []string {
-	primaryType = strings.TrimSuffix(primaryType, "[]")
+	primaryType = strings.Split(primaryType, "[")[0]
 
 	if slices.Contains(found, primaryType) {
 		return found
@@ -465,34 +464,11 @@ func (typedData *TypedData) EncodeData(primaryType string, data map[string]inter
 		encType := field.Type
 		encValue := data[field.Name]
 		if encType[len(encType)-1:] == "]" {
-			arrayValue, err := convertDataToSlice(encValue)
+			encodedData, err := typedData.encodeArrayValue(encValue, encType, depth)
 			if err != nil {
-				return nil, dataMismatchError(encType, encValue)
+				return nil, err
 			}
-
-			arrayBuffer := bytes.Buffer{}
-			parsedType := strings.Split(encType, "[")[0]
-			for _, item := range arrayValue {
-				if typedData.Types[parsedType] != nil {
-					mapValue, ok := item.(map[string]interface{})
-					if !ok {
-						return nil, dataMismatchError(parsedType, item)
-					}
-					encodedData, err := typedData.EncodeData(parsedType, mapValue, depth+1)
-					if err != nil {
-						return nil, err
-					}
-					arrayBuffer.Write(crypto.Keccak256(encodedData))
-				} else {
-					bytesValue, err := typedData.EncodePrimitiveValue(parsedType, item, depth)
-					if err != nil {
-						return nil, err
-					}
-					arrayBuffer.Write(bytesValue)
-				}
-			}
-
-			buffer.Write(crypto.Keccak256(arrayBuffer.Bytes()))
+			buffer.Write(encodedData)
 		} else if typedData.Types[field.Type] != nil {
 			mapValue, ok := encValue.(map[string]interface{})
 			if !ok {
@@ -514,6 +490,46 @@ func (typedData *TypedData) EncodeData(primaryType string, data map[string]inter
 	return buffer.Bytes(), nil
 }
 
+func (typedData *TypedData) encodeArrayValue(encValue interface{}, encType string, depth int) (hexutil.Bytes, error) {
+	arrayValue, err := convertDataToSlice(encValue)
+	if err != nil {
+		return nil, dataMismatchError(encType, encValue)
+	}
+
+	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)
+			if err != nil {
+				return nil, err
+			}
+			arrayBuffer.Write(encodedData)
+		} else {
+			if typedData.Types[parsedType] != nil {
+				mapValue, ok := item.(map[string]interface{})
+				if !ok {
+					return nil, dataMismatchError(parsedType, item)
+				}
+				encodedData, err := typedData.EncodeData(parsedType, mapValue, depth+1)
+				if err != nil {
+					return nil, err
+				}
+				digest := crypto.Keccak256(encodedData)
+				arrayBuffer.Write(digest)
+			} else {
+				bytesValue, err := typedData.EncodePrimitiveValue(parsedType, item, depth)
+				if err != nil {
+					return nil, err
+				}
+				arrayBuffer.Write(bytesValue)
+			}
+		}
+	}
+	return crypto.Keccak256(arrayBuffer.Bytes()), nil
+}
+
 // Attempt to parse bytes in different formats: byte array, hex string, hexutil.Bytes.
 func parseBytes(encType interface{}) ([]byte, bool) {
 	// Handle array types.
@@ -871,7 +887,8 @@ func init() {
 
 // Checks if the primitive value is valid
 func isPrimitiveTypeValid(primitiveType string) bool {
-	_, ok := validPrimitiveTypes[primitiveType]
+	input := strings.Split(primitiveType, "[")[0]
+	_, ok := validPrimitiveTypes[input]
 	return ok
 }
 

signer/core/apitypes/types_test.go

@@ -31,8 +31,9 @@ func TestIsPrimitive(t *testing.T) {
 	t.Parallel()
 	// Expected positives
 	for i, tc := range []string{
-		"int24", "int24[]", "uint88", "uint88[]", "uint", "uint[]", "int256", "int256[]",
-		"uint96", "uint96[]", "int96", "int96[]", "bytes17[]", "bytes17",
+		"int24", "int24[]", "int[]", "int[2]", "uint88", "uint88[]", "uint", "uint[]", "uint[2]", "int256", "int256[]",
+		"uint96", "uint96[]", "int96", "int96[]", "bytes17[]", "bytes17", "address[2]", "bool[4]", "string[5]", "bytes[2]",
+		"bytes32", "bytes32[]", "bytes32[4]",
 	} {
 		if !isPrimitiveTypeValid(tc) {
 			t.Errorf("test %d: expected '%v' to be a valid primitive", i, tc)
@@ -141,3 +142,94 @@ func TestBlobTxs(t *testing.T) {
 	}
 	t.Logf("tx %v", string(data))
 }
+
+func TestType_IsArray(t *testing.T) {
+	t.Parallel()
+	// Expected positives
+	for i, tc := range []Type{
+		{
+			Name: "type1",
+			Type: "int24[]",
+		},
+		{
+			Name: "type2",
+			Type: "int24[2]",
+		},
+		{
+			Name: "type3",
+			Type: "int24[2][2][2]",
+		},
+	} {
+		if !tc.isArray() {
+			t.Errorf("test %d: expected '%v' to be an array", i, tc)
+		}
+	}
+	// Expected negatives
+	for i, tc := range []Type{
+		{
+			Name: "type1",
+			Type: "int24",
+		},
+		{
+			Name: "type2",
+			Type: "uint88",
+		},
+		{
+			Name: "type3",
+			Type: "bytes32",
+		},
+	} {
+		if tc.isArray() {
+			t.Errorf("test %d: expected '%v' to not be an array", i, tc)
+		}
+	}
+}
+
+func TestType_TypeName(t *testing.T) {
+	t.Parallel()
+
+	for i, tc := range []struct {
+		Input    Type
+		Expected string
+	}{
+		{
+			Input: Type{
+				Name: "type1",
+				Type: "int24[]",
+			},
+			Expected: "int24",
+		},
+		{
+			Input: Type{
+				Name: "type2",
+				Type: "int26[2][2][2]",
+			},
+			Expected: "int26",
+		},
+		{
+			Input: Type{
+				Name: "type3",
+				Type: "int24",
+			},
+			Expected: "int24",
+		},
+		{
+			Input: Type{
+				Name: "type4",
+				Type: "uint88",
+			},
+			Expected: "uint88",
+		},
+		{
+			Input: Type{
+				Name: "type5",
+				Type: "bytes32[2]",
+			},
+			Expected: "bytes32",
+		},
+	} {
+		if tc.Input.typeName() != tc.Expected {
+			t.Errorf("test %d: expected typeName value of '%v' but got '%v'", i, tc.Expected, tc.Input)
+		}
+	}
+}