[PATCH] ShellPkg/for: Fix potential null pointer deference

[PATCH] ShellPkg/for: Fix potential null pointer deference

[Ruiyu Ni]

When "FOR %a %a IN A B C" is executed,
CurrentScriptFile->CurrentCommand->Data is NULL.
But the code assumes it's not NULL and tries to
deference it.

The patch fixes this issue.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jaben Carsey <jaben.carsey@intel.com>
---
 ShellPkg/Library/UefiShellLevel1CommandsLib/For.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c b/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c
index 3db4bb58d3..9824977149 100644
--- a/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c
+++ b/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c
@@ -2,7 +2,7 @@
   Main file for endfor and for shell level 1 functions.
 
   (C) Copyright 2015 Hewlett-Packard Development Company, L.P.<BR>
-  Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -624,7 +624,9 @@ ShellCommandRunFor (
   if (CurrentScriptFile != NULL && CurrentScriptFile->CurrentCommand != NULL) {
     Info = (SHELL_FOR_INFO*)CurrentScriptFile->CurrentCommand->Data;
     if (CurrentScriptFile->CurrentCommand->Reset) {
-      Info->CurrentValue  = (CHAR16*)Info->Set;
+      if (Info != NULL) {
+        Info->CurrentValue = (CHAR16*)Info->Set;
+      }
       FirstPass = TRUE;
       CurrentScriptFile->CurrentCommand->Reset = FALSE;
     }
-- 
2.16.1.windows.1

Re: [PATCH] ShellPkg/for: Fix potential null pointer deference

[Carsey, Jaben]

Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>

> -----Original Message-----
> From: Ni, Ruiyu
> Sent: Sunday, February 04, 2018 11:54 PM
> To: edk2-devel@lists.01.org
> Cc: Carsey, Jaben <jaben.carsey@intel.com>
> Subject: [PATCH] ShellPkg/for: Fix potential null pointer deference
> Importance: High
> 
> When "FOR %a %a IN A B C" is executed,
> CurrentScriptFile->CurrentCommand->Data is NULL.
> But the code assumes it's not NULL and tries to
> deference it.
> 
> The patch fixes this issue.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Jaben Carsey <jaben.carsey@intel.com>
> ---
>  ShellPkg/Library/UefiShellLevel1CommandsLib/For.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c
> b/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c
> index 3db4bb58d3..9824977149 100644
> --- a/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c
> +++ b/ShellPkg/Library/UefiShellLevel1CommandsLib/For.c
> @@ -2,7 +2,7 @@
>    Main file for endfor and for shell level 1 functions.
> 
>    (C) Copyright 2015 Hewlett-Packard Development Company, L.P.<BR>
> -  Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
>    This program and the accompanying materials
>    are licensed and made available under the terms and conditions of the BSD
> License
>    which accompanies this distribution.  The full text of the license may be
> found at
> @@ -624,7 +624,9 @@ ShellCommandRunFor (
>    if (CurrentScriptFile != NULL && CurrentScriptFile->CurrentCommand !=
> NULL) {
>      Info = (SHELL_FOR_INFO*)CurrentScriptFile->CurrentCommand->Data;
>      if (CurrentScriptFile->CurrentCommand->Reset) {
> -      Info->CurrentValue  = (CHAR16*)Info->Set;
> +      if (Info != NULL) {
> +        Info->CurrentValue = (CHAR16*)Info->Set;
> +      }
>        FirstPass = TRUE;
>        CurrentScriptFile->CurrentCommand->Reset = FALSE;
>      }
> --
> 2.16.1.windows.1