Re: [PATCH V3 3/3] DuetPkg FsVariable: Update GetNextVariableName to follow UEFI 2.7

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

Thanks/Ray

> -----Original Message-----
> From: Zeng, Star
> Sent: Monday, June 26, 2017 5:21 PM
> To: edk2-devel@lists.01.org
> Cc: Zeng, Star <star.zeng@intel.com>; Gao, Liming <liming.gao@intel.com>;
> Ni, Ruiyu <ruiyu.ni@intel.com>
> Subject: [PATCH V3 3/3] DuetPkg FsVariable: Update GetNextVariableName
> to follow UEFI 2.7
> 
> "The size must be large enough to fit input string supplied in VariableName
> buffer" is added in the description for VariableNameSize.
> And two cases of EFI_INVALID_PARAMETER are added.
> 1. The input values of VariableName and VendorGuid are not a name and
>    GUID of an existing variable.
> 2. Null-terminator is not found in the first VariableNameSize bytes of
>    the input VariableName buffer.
> 
> This patch is to update code to follow them.
> 
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> Reviewed-by: Liming Gao <liming.gao@intel.com>
> ---
>  DuetPkg/FSVariable/FSVariable.c | 31
> +++++++++++++++++++++++++++++--
>  1 file changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/DuetPkg/FSVariable/FSVariable.c
> b/DuetPkg/FSVariable/FSVariable.c index 34b79305c871..5feeade10d2f
> 100644
> --- a/DuetPkg/FSVariable/FSVariable.c
> +++ b/DuetPkg/FSVariable/FSVariable.c
> @@ -6,7 +6,7 @@ disk. They can be changed by user. BIOS is not able to
> protoect those.
>  Duet trusts all meta data from disk. If variable code, variable metadata and
> variable  data is modified in inproper way, the behavior is undefined.
> 
> -Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2006 - 2017, 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
> @@ -1387,7 +1387,8 @@ Routine Description:
> 
>  Arguments:
> 
> -  VariableNameSize            Size of the variable
> +  VariableNameSize            The size of the VariableName buffer. The size
> must be large
> +                              enough to fit input string supplied in VariableName buffer.
>    VariableName                Pointer to variable name
>    VendorGuid                  Variable Vendor Guid
> 
> @@ -1400,14 +1401,40 @@ Returns:
>    VARIABLE_POINTER_TRACK  Variable;
>    UINTN                   VarNameSize;
>    EFI_STATUS              Status;
> +  UINTN                   MaxLen;
> 
>    if (VariableNameSize == NULL || VariableName == NULL || VendorGuid ==
> NULL) {
>      return EFI_INVALID_PARAMETER;
>    }
> 
> +  //
> +  // Calculate the possible maximum length of name string, including the Null
> terminator.
> +  //
> +  MaxLen = *VariableNameSize / sizeof (CHAR16);  if ((MaxLen == 0) ||
> + (StrnLenS (VariableName, MaxLen) == MaxLen)) {
> +    //
> +    // Null-terminator is not found in the first VariableNameSize bytes of the
> input VariableName buffer,
> +    // follow spec to return EFI_INVALID_PARAMETER.
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
>    Status = FindVariable (VariableName, VendorGuid, &Variable);
> 
>    if (Variable.CurrPtr == NULL || EFI_ERROR (Status)) {
> +    //
> +    // For VariableName is an empty string, FindVariable() will try to find and
> return
> +    // the first qualified variable, and if FindVariable() returns error
> (EFI_NOT_FOUND)
> +    // as no any variable is found, still go to return the error
> (EFI_NOT_FOUND).
> +    //
> +    if (VariableName[0] != 0) {
> +      //
> +      // For VariableName is not an empty string, and FindVariable() returns
> error as
> +      // VariableName and VendorGuid are not a name and GUID of an
> existing variable,
> +      // there is no way to get next variable, follow spec to return
> EFI_INVALID_PARAMETER.
> +      //
> +      Status = EFI_INVALID_PARAMETER;
> +    }
>      return Status;
>    }
> 
> --
> 2.7.0.windows.1