Re: [PATCH] ShellPkg/map: Fix out-of-bound read when "map fsn"

["Carsey, Jaben" <jaben.carsey@intel.com>]

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

> -----Original Message-----
> From: Ni, Ruiyu
> Sent: Sunday, February 04, 2018 9:50 PM
> To: edk2-devel@lists.01.org
> Cc: Carsey, Jaben <jaben.carsey@intel.com>; Wang, Jian J
> <jian.j.wang@intel.com>
> Subject: [PATCH] ShellPkg/map: Fix out-of-bound read when "map fsn"
> Importance: High
> 
> The below code reads additional one CHAR16 when copying
> content from Specific to NewSpecific.
> NewSpecific = AllocateCopyPool(
>                 StrSize(Specific) + sizeof(CHAR16), Specific
>                 );
> 
> 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>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> ---
>  ShellPkg/Library/UefiShellLevel2CommandsLib/Map.c | 18 ++++++++++++--
> ----
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/ShellPkg/Library/UefiShellLevel2CommandsLib/Map.c
> b/ShellPkg/Library/UefiShellLevel2CommandsLib/Map.c
> index 3f5925f507..9166ca2205 100644
> --- a/ShellPkg/Library/UefiShellLevel2CommandsLib/Map.c
> +++ b/ShellPkg/Library/UefiShellLevel2CommandsLib/Map.c
> @@ -1,7 +1,7 @@
>  /** @file
>    Main file for map shell level 2 command.
> 
> -  Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
>    (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.<BR>
>    (C) Copyright 2016 Hewlett Packard Enterprise Development LP<BR>
> 
> @@ -220,19 +220,25 @@ MappingListHasType(
>    IN CONST BOOLEAN    Consist
>    )
>  {
> -  CHAR16 *NewSpecific;
> -  RETURN_STATUS  Status;
> +  CHAR16              *NewSpecific;
> +  RETURN_STATUS       Status;
> +  UINTN               Length;
> 
>    //
>    // specific has priority
>    //
>    if (Specific != NULL) {
> -    NewSpecific = AllocateCopyPool(StrSize(Specific) + sizeof(CHAR16),
> Specific);
> +    Length      = StrLen (Specific);
> +    //
> +    // Allocate enough buffer for Specific and potential ":"
> +    //
> +    NewSpecific = AllocatePool ((Length + 2) * sizeof(CHAR16));
>      if (NewSpecific == NULL){
>        return FALSE;
>      }
> -    if (NewSpecific[StrLen(NewSpecific)-1] != L':') {
> -      Status = StrnCatS(NewSpecific, (StrSize(Specific) +
> sizeof(CHAR16))/sizeof(CHAR16), L":", StrLen(L":"));
> +    StrCpyS (NewSpecific, Length + 2, Specific);
> +    if (Specific[Length - 1] != L':') {
> +      Status = StrnCatS(NewSpecific, Length + 2, L":", StrLen(L":"));
>        if (EFI_ERROR (Status)) {
>          FreePool(NewSpecific);
>          return FALSE;
> --
> 2.16.1.windows.1