Re: [PATCH v2] MdePkg/BaseMemoryLibOptDxe: check for zero length in ZeroMem ()

["Gao, Liming" <liming.gao@intel.com>]

Ard:
  Could you help apply this changes for other BaseMemoryLib instances in MdePkg? 

Thanks
Liming
> -----Original Message-----
> From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
> Sent: Friday, November 04, 2016 2:18 AM
> To: edk2-devel@lists.01.org; Kinney, Michael D
> <michael.d.kinney@intel.com>; Gao, Liming <liming.gao@intel.com>
> Cc: lersek@redhat.com; Carsey, Jaben <jaben.carsey@intel.com>; Ard
> Biesheuvel <ard.biesheuvel@linaro.org>
> Subject: [PATCH v2] MdePkg/BaseMemoryLibOptDxe: check for zero length
> in ZeroMem ()
> 
> Unlike other string functions in this library, ZeroMem () does not
> return early when the length of the input buffer is 0. So add the
> same to ZeroMem () as well.
> 
> This fixes an issue with the ARM implementation, whose
> InternalMemZeroMem
> code does not expect a length of 0, and always writes at least a single
> byte.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c
> b/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c
> index 2a0a038fd6c5..9dd0b45e188e 100644
> --- a/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c
> +++ b/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c
> @@ -46,7 +46,11 @@ ZeroMem (
>    IN UINTN  Length
>    )
>  {
> -  ASSERT (!(Buffer == NULL && Length > 0));
> +  if (Length == 0) {
> +    return Buffer;
> +  }
> +
> +  ASSERT (Buffer != NULL);
>    ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
>    return InternalMemZeroMem (Buffer, Length);
>  }
> --
> 2.7.4