diff --git a/grub-core/osdep/unix/hostdisk.c b/grub-core/osdep/unix/hostdisk.c
index 3a00d7451..353db01f6 100644
--- a/grub-core/osdep/unix/hostdisk.c
+++ b/grub-core/osdep/unix/hostdisk.c
@@ -101,6 +101,9 @@ grub_util_fd_read (grub_util_fd_t fd, char *buf, size_t len)
 {
   ssize_t size = 0;
 
+  if (len > SSIZE_MAX)
+    return -1;
+
   while (len)
     {
       ssize_t ret = read (fd, buf, len);
@@ -131,6 +134,9 @@ grub_util_fd_write (grub_util_fd_t fd, const char *buf, size_t len)
 {
   ssize_t size = 0;
 
+  if (len > SSIZE_MAX)
+    return -1;
+
   while (len)
     {
       ssize_t ret = write (fd, buf, len);