Vboot Reference: Make length types explicitly sized.

src/platform/vboot_reference/utils/file_keys.c

Index: src/platform/vboot_reference/utils/file_keys.c
diff --git a/src/platform/vboot_reference/utils/file_keys.c b/src/platform/vboot_reference/utils/file_keys.c
index 4eafd524523adcee3d8c2a688ad26d87b4b09373..84383514d8d7d54ca57a8de7b92c790d6beef7a8 100644
--- a/src/platform/vboot_reference/utils/file_keys.c
+++ b/src/platform/vboot_reference/utils/file_keys.c
@@ -20,7 +20,7 @@
 #include "signature_digest.h"
 #include "utility.h"
 
-uint8_t* BufferFromFile(const char* input_file, uint32_t* len) {
+uint8_t* BufferFromFile(const char* input_file, uint64_t* len) {
   int fd;
   struct stat stat_fd;
   uint8_t* buf = NULL;
@@ -51,7 +51,7 @@ uint8_t* BufferFromFile(const char* input_file, uint32_t* len) {
 }
 
 RSAPublicKey* RSAPublicKeyFromFile(const char* input_file) {
-  uint32_t len;
+  uint64_t len;
   RSAPublicKey* key = NULL;
   uint8_t* buf = BufferFromFile(input_file, &len);
   if (buf)