Use uint64_t and avoid down casting as much as possible.

host/lib/host_key.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Host functions for keys.
  */
 
 /* TODO: change all 'return 0', 'return 1' into meaningful return codes */
 
 #define OPENSSL_NO_SHA
@@ skipping 149 matching lines @@
   key->key_size = key_size;
   key->key_offset = sizeof(VbPublicKey);
   return key;
 }
 
 VbPublicKey* PublicKeyReadKeyb(const char* filename, uint64_t algorithm,
                                uint64_t version) {
   VbPublicKey* key;
   uint8_t* key_data;
   uint64_t key_size;
-  int expected_key_size;
+  uint64_t expected_key_size;
 
   if (algorithm >= kNumAlgorithms) {
     VBDEBUG(("PublicKeyReadKeyb() called with invalid algorithm!\n"));
     return NULL;
   }
   if (version > 0xFFFF) {
     /* Currently, TPM only supports 16-bit version */
     VBDEBUG(("PublicKeyReadKeyb() called with invalid version!\n"));
     return NULL;
   }
@@ skipping 17 matching lines @@
   Memcpy(GetPublicKeyData(key), key_data, key_size);
 
   Free(key_data);
   return key;
 }
 
 
 VbPublicKey* PublicKeyRead(const char* filename) {
   VbPublicKey* key;
   uint64_t file_size;
-  int key_size;
+  uint64_t key_size;
 
   key = (VbPublicKey*)ReadFile(filename, &file_size);
   if (!key)
     return NULL;
 
   do {
     /* Sanity-check key data */
     if (0 != VerifyPublicKeyInside(key, file_size, key)) {
       VBDEBUG(("PublicKeyRead() not a VbPublicKey\n"));
       break;
@@ skipping 33 matching lines @@
   if (0 != PublicKeyCopy(kcopy, key)) {
     Free(kcopy);
     return 1;
   }
 
   /* Write the copy, then free it */
   rv = WriteFile(filename, kcopy, kcopy->key_offset + kcopy->key_size);
   Free(kcopy);
   return rv;
 }