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From: "Gao, Liming" <liming.gao@intel.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	"edk2-devel@lists.01.org" <edk2-devel@lists.01.org>,
	"Kinney, Michael D" <michael.d.kinney@intel.com>
Cc: "Carsey, Jaben" <jaben.carsey@intel.com>,
	"lersek@redhat.com" <lersek@redhat.com>
Subject: Re: [PATCH v3] MdePkg/BaseMemoryLib*: check for zero length in ZeroMem ()
Date: Fri, 4 Nov 2016 09:08:26 +0000	[thread overview]
Message-ID: <4A89E2EF3DFEDB4C8BFDE51014F606A14B49ECCA@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <1478250278-27796-1-git-send-email-ard.biesheuvel@linaro.org>

Reviewed-by: Liming Gao <liming.gao@intel.com>

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Ard Biesheuvel
> Sent: Friday, November 04, 2016 5:05 PM
> To: edk2-devel@lists.01.org; Kinney, Michael D
> <michael.d.kinney@intel.com>; Gao, Liming <liming.gao@intel.com>
> Cc: Carsey, Jaben <jaben.carsey@intel.com>; lersek@redhat.com; Ard
> Biesheuvel <ard.biesheuvel@linaro.org>
> Subject: [edk2] [PATCH v3] MdePkg/BaseMemoryLib*: 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, for all implementations of BaseMemoryLib
> living under MdePkg/
> 
> This fixes an issue with the ARM implementation of BaseMemoryLibOPtDxe,
> 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>
> Acked-by: Laszlo Ersek <lersek@redhat.com>
> ---
>  MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c       | 6 +++++-
>  MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c    | 6 +++++-
>  MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c | 6 +++++-
>  MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c | 6 +++++-
>  MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c | 6 +++++-
>  MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c   | 6 +++++-
>  MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c        | 6 +++++-
>  MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c       | 6 +++++-
>  8 files changed, 40 insertions(+), 8 deletions(-)
> 
> diff --git a/MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c
> b/MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c
> index 2a0a038fd6c5..9dd0b45e188e 100644
> --- a/MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c
> +++ b/MdePkg/Library/BaseMemoryLib/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);
>  }
> diff --git a/MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c
> b/MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c
> index 2a0a038fd6c5..9dd0b45e188e 100644
> --- a/MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c
> +++ b/MdePkg/Library/BaseMemoryLibMmx/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);
>  }
> 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);
>  }
> diff --git a/MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c
> b/MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c
> index 2a0a038fd6c5..9dd0b45e188e 100644
> --- a/MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c
> +++ b/MdePkg/Library/BaseMemoryLibOptPei/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);
>  }
> diff --git a/MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c
> b/MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c
> index 2a0a038fd6c5..9dd0b45e188e 100644
> --- a/MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c
> +++ b/MdePkg/Library/BaseMemoryLibRepStr/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);
>  }
> diff --git a/MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c
> b/MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c
> index 2a0a038fd6c5..9dd0b45e188e 100644
> --- a/MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c
> +++ b/MdePkg/Library/BaseMemoryLibSse2/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);
>  }
> diff --git a/MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c
> b/MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c
> index 5adddbbfad66..a3aa7d10a689 100644
> --- a/MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c
> +++ b/MdePkg/Library/PeiMemoryLib/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);
>  }
> diff --git a/MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c
> b/MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c
> index 5adddbbfad66..a3aa7d10a689 100644
> --- a/MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c
> +++ b/MdePkg/Library/UefiMemoryLib/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
> 
> _______________________________________________
> edk2-devel mailing list
> edk2-devel@lists.01.org
> https://lists.01.org/mailman/listinfo/edk2-devel


  reply	other threads:[~2016-11-04  9:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-04  9:04 [PATCH v3] MdePkg/BaseMemoryLib*: check for zero length in ZeroMem () Ard Biesheuvel
2016-11-04  9:08 ` Gao, Liming [this message]
2016-11-04  9:54   ` Ard Biesheuvel

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