Re: [PATCH] MdeModulePkg/Bds: Validate the device path stored in Boot####

["Zeng, Star" <star.zeng@intel.com>]

VarCheckUefiLib InternalVarCheckLoadOption() can make sure the device path in load option Variable Data is valid.

If we do not assume VarCheckUefiLib will be always linked, I am ok with this patch.

Reviewed-by: Star Zeng <star.zeng@intel.com>


Thanks,
Star
-----Original Message-----
From: Ni, Ruiyu 
Sent: Wednesday, April 25, 2018 1:51 PM
To: edk2-devel@lists.01.org
Cc: Zeng, Star <star.zeng@intel.com>; Zhang, Chao B <chao.b.zhang@intel.com>
Subject: [PATCH] MdeModulePkg/Bds: Validate the device path stored in Boot####

The patch adds additional check to the device path when loading the Boot####/Driver#### variable data.
If the device path is invalid, InvalidParameter is returned.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Chao B Zhang <chao.b.zhang@intel.com>
---
 MdeModulePkg/Library/UefiBootManagerLib/BmLoadOption.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/MdeModulePkg/Library/UefiBootManagerLib/BmLoadOption.c b/MdeModulePkg/Library/UefiBootManagerLib/BmLoadOption.c
index 32918caf32..b48a3cbd37 100644
--- a/MdeModulePkg/Library/UefiBootManagerLib/BmLoadOption.c
+++ b/MdeModulePkg/Library/UefiBootManagerLib/BmLoadOption.c
@@ -1,7 +1,7 @@
 /** @file
   Load option library functions which relate with creating and processing load options.
 
-Copyright (c) 2011 - 2017, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2011 - 2018, Intel Corporation. All rights reserved.<BR>
 (C) Copyright 2015-2016 Hewlett Packard Enterprise Development LP<BR>  This program and the accompanying materials  are licensed and made available under the terms and conditions of the BSD License @@ -922,10 +922,14 @@ EfiBootManagerVariableToLoadOptionEx (
   VariablePtr += StrSize ((CHAR16 *) VariablePtr);
 
   //
-  // Get the option's device path
+  // Get the option's device path and validate it.
   //
   FilePath = (EFI_DEVICE_PATH_PROTOCOL *) VariablePtr;
   VariablePtr += FilePathSize;
+  if (!IsDevicePathValid (FilePath, FilePathSize)) {
+    FreePool (Variable);
+    return EFI_INVALID_PARAMETER;
+  }
 
   OptionalDataSize = (UINT32) (VariableSize - ((UINTN) VariablePtr - (UINTN) Variable));
   if (OptionalDataSize == 0) {
--
2.16.1.windows.1