WIP field hashing

src_features/signMessageEIP712/encode_field.c

@@ -0,0 +1,129 @@
+#include <stdlib.h>
+#include <string.h>
+#include "encode_field.h"
+#include "mem.h"
+#include "eip712.h"
+#include "shared_context.h"
+
+
+/**
+ * Hash field value
+ *
+ * @param[in] value pointer to value
+ * @param[in] length its bytelength
+ * @param[in] dealloc if the value length should be deallocated from the memory
+ */
+static void *hash_field_value(const void *const value, uint16_t length, bool dealloc)
+{
+    uint8_t *hash_ptr = NULL;
+
+    if (value != NULL)
+    {
+        cx_keccak_init((cx_hash_t*)&global_sha3, 256);
+        cx_hash((cx_hash_t*)&global_sha3,
+                0,
+                (uint8_t*)value,
+                length,
+                NULL,
+                0);
+
+        if (dealloc)
+        {
+            // restore the memory location
+            mem_dealloc(length);
+        }
+
+        if ((hash_ptr = mem_alloc(KECCAK256_HASH_BYTESIZE)) == NULL)
+        {
+            return NULL;
+        }
+
+        // copy hash into memory
+        cx_hash((cx_hash_t*)&global_sha3,
+                CX_LAST,
+                NULL,
+                0,
+                hash_ptr,
+                KECCAK256_HASH_BYTESIZE);
+    }
+    return hash_ptr;
+}
+
+/**
+ * Encode an integer and hash it
+ *
+ * @param[in] value pointer to the "packed" integer received
+ * @param[in] length its byte-length
+ * @return the encoded (hashed) value
+ */
+void    *encode_integer(const uint8_t *const value, uint16_t length)
+{
+    uint8_t *padded_value;
+
+    // 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);
+        for (uint8_t idx = 0; idx < length; ++idx)
+        {
+            padded_value[EIP_712_ENCODED_FIELD_LENGTH - (length - idx)] = value[idx];
+        }
+    }
+    return hash_field_value(padded_value, EIP_712_ENCODED_FIELD_LENGTH, true);
+}
+
+/**
+ * Encode a string and hash it
+ *
+ * @param[in] value pointer to the string received
+ * @param[in] length its byte-length
+ * @return the encoded (hashed) value
+ */
+void    *encode_string(const char *const value, uint16_t length)
+{
+    return hash_field_value(value, length, false);
+}
+
+/**
+ * Encode a boolean and hash it
+ *
+ * @param[in] value pointer to the boolean received
+ * @param[in] length its byte-length
+ * @return the encoded (hashed) value
+ */
+void    *encode_bool(const bool *const value, uint16_t length)
+{
+    if (length != 1)
+    {
+        return NULL;
+    }
+    return encode_integer((uint8_t*)value, length);
+}
+
+/**
+ * Encode an address and hash it
+ *
+ * @param[in] value pointer to the address received
+ * @param[in] length its byte-length
+ * @return the encoded (hashed) value
+ */
+void    *encode_address(const uint8_t *const value, uint16_t length)
+{
+    if (length != ADDRESS_LENGTH)
+    {
+        return NULL;
+    }
+    return encode_integer(value, length);
+}
+
+/**
+ * Encode bytes and hash it
+ *
+ * @param[in] value pointer to the bytes received
+ * @param[in] length its byte-length
+ * @return the encoded (hashed) value
+ */
+void    *encode_bytes(const uint8_t *const value, uint16_t length)
+{
+    return hash_field_value(value, length, false);
+}