Fix dynamic bytes type encoding

src_features/signMessageEIP712/encode_field.c

@@ -5,17 +5,23 @@
 #include "eip712.h"
 #include "shared_context.h"
 
+typedef enum
+{
+    MSB,
+    LSB
+}   e_padding_type;
 
 /**
- * Encode a field value to 32 bytes
+ * Encode a field value to 32 bytes (0 padded)
  *
  * @param[in] value field value to encode
  * @param[in] length field length before encoding
  * @return encoded field value
  */
-static void *field_encode(const uint8_t *const value, uint8_t length)
+static void *field_encode(const uint8_t *const value, uint8_t length, e_padding_type ptype)
 {
     uint8_t *padded_value;
+    uint8_t start_idx;
 
     if (length > 32) // sanity check
     {
@@ -24,10 +30,22 @@ static void *field_encode(const uint8_t *const value, uint8_t length)
     // 0-pad the value to 32 bytes
     if ((padded_value = mem_alloc(EIP_712_ENCODED_FIELD_LENGTH)) != NULL)
     {
-        explicit_bzero(padded_value, EIP_712_ENCODED_FIELD_LENGTH - length);
+        switch (ptype)
+        {
+            case MSB:
+                explicit_bzero(padded_value, EIP_712_ENCODED_FIELD_LENGTH - length);
+                start_idx = EIP_712_ENCODED_FIELD_LENGTH - length;
+                break;
+            case LSB:
+                explicit_bzero(padded_value + length, EIP_712_ENCODED_FIELD_LENGTH - length);
+                start_idx = 0;
+                break;
+            default:
+                return NULL; // should not be here
+        }
         for (uint8_t idx = 0; idx < length; ++idx)
         {
-            padded_value[EIP_712_ENCODED_FIELD_LENGTH - (length - idx)] = value[idx];
+            padded_value[start_idx + idx] = value[idx];
         }
     }
     return padded_value;
@@ -38,12 +56,25 @@ static void *field_encode(const uint8_t *const value, uint8_t length)
  *
  * @param[in] value pointer to the "packed" integer received
  * @param[in] length its byte-length
- * @return the encoded (hashed) value
+ * @return the encoded value
  */
 void    *encode_integer(const uint8_t *const value, uint8_t length)
 {
     // no length check here since it will be checked by field_encode
-    return field_encode(value, length);
+    return field_encode(value, length, MSB);
+}
+
+/**
+ * Encode a fixed-size byte array
+ *
+ * @param[in] value pointer to the "packed" bytes array
+ * @param[in] length its byte-length
+ * @return the encoded value
+ */
+void    *encode_bytes(const uint8_t *const value, uint8_t length)
+{
+    // no length check here since it will be checked by field_encode
+    return field_encode(value, length, LSB);
 }
 
 /**
@@ -51,7 +82,7 @@ void    *encode_integer(const uint8_t *const value, uint8_t length)
  *
  * @param[in] value pointer to the boolean received
  * @param[in] length its byte-length
- * @return the encoded (hashed) value
+ * @return the encoded value
  */
 void    *encode_boolean(const bool *const value, uint8_t length)
 {
@@ -67,7 +98,7 @@ void    *encode_boolean(const bool *const value, uint8_t length)
  *
  * @param[in] value pointer to the address received
  * @param[in] length its byte-length
- * @return the encoded (hashed) value
+ * @return the encoded value
  */
 void    *encode_address(const uint8_t *const value, uint8_t length)
 {

src_features/signMessageEIP712/encode_field.h

@@ -9,5 +9,6 @@
 void    *encode_integer(const uint8_t *const value, uint8_t length);
 void    *encode_boolean(const bool *const value, uint8_t length);
 void    *encode_address(const uint8_t *const value, uint8_t length);
+void    *encode_bytes(const uint8_t *const value, uint8_t length);
 
 #endif // ENCODE_FIELD_H_

src_features/signMessageEIP712/field_hash.c

@@ -88,9 +88,11 @@ const uint8_t *field_hash(const uint8_t *data,
             {
                 case TYPE_SOL_INT:
                 case TYPE_SOL_UINT:
-                case TYPE_SOL_BYTES_FIX:
                     value = encode_integer(data, data_length);
                     break;
+                case TYPE_SOL_BYTES_FIX:
+                    value = encode_bytes(data, data_length);
+                    break;
                 case TYPE_SOL_ADDRESS:
                     value = encode_address(data, data_length);
                     break;