From: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>
Date: Tue, 1 May 2012 13:08:29 +0000 (+0200)
Subject: 	* grub-core/kern/file.c (grub_file_read): Read nothing if len = 0.
X-Git-Tag: 2.00~286
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a188012e6c831dd5355cadfc8f3848aaa74a703f;p=thirdparty%2Fgrub.git

	* grub-core/kern/file.c (grub_file_read): Read nothing if len = 0.
	Special behaviour for len = 0 to read whole file isn't used anywhere and
	can cause buffer ovewrflows in several places.
---

diff --git a/ChangeLog b/ChangeLog
index 9c06c24ba..293449491 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2012-05-01  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/kern/file.c (grub_file_read): Read nothing if len = 0.
+	Special behaviour for len = 0 to read whole file isn't used anywhere and
+	can cause buffer ovewrflows in several places.
+
 2012-05-01  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/normal/autofs.c (read_fs_list): Fix memory leak.
diff --git a/grub-core/kern/file.c b/grub-core/kern/file.c
index 4f1f59ff7..495326f12 100644
--- a/grub-core/kern/file.c
+++ b/grub-core/kern/file.c
@@ -143,7 +143,10 @@ grub_file_read (grub_file_t file, void *buf, grub_size_t len)
       return -1;
     }
 
-  if (len == 0 || len > file->size - file->offset)
+  if (len == 0)
+    return 0;
+
+  if (len > file->size - file->offset)
     len = file->size - file->offset;
 
   /* Prevent an overflow.  */