diff --git a/ChangeLog b/ChangeLog
index 4a4a9bf0a..7dcc83ee8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2012-05-06  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/fs/affs.c (grub_affs_read_block): Fix theoretical overflow.
+
 2012-05-06  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/commands/ls.c (grub_ls_list_files): Fix overflow.
diff --git a/grub-core/fs/affs.c b/grub-core/fs/affs.c
index 50ab8026b..bcb630b6c 100644
--- a/grub-core/fs/affs.c
+++ b/grub-core/fs/affs.c
@@ -129,8 +129,8 @@ grub_affs_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
 
   if (!node->block_cache)
     {
-      node->block_cache = grub_malloc ((((grub_be_to_cpu32 (node->di.size)
-					  + 511) >> 9)  / data->htsize + 1)
+      node->block_cache = grub_malloc (((grub_be_to_cpu32 (node->di.size)
+					  >> 9)  / data->htsize + 2)
 				       * sizeof (node->block_cache[0]));
       if (!node->block_cache)
 	return -1;