Re: [edk2-devel] [PATCH v2 1/1] SecurityPkg: Fix incorrect return value when File is NULL

["Laszlo Ersek" <lersek@redhat.com>]

On 02/07/20 01:04, Philippe Mathieu-Daudé wrote:
> The DxeTpmMeasureBootHandler and DxeTpm2MeasureBootHandler handlers
> are SECURITY2_FILE_AUTHENTICATION_HANDLER prototype. This prototype
> can not return EFI_INVALID_PARAMETER.
> 
> The prototype documentation states it returns EFI_ACCESS_DENIED if:
> 
>   "The file specified by File and FileBuffer did not authenticate,
>    and the platform policy dictates that the DXE Foundation may not
>    use File."
> 
> Correct the documentation, and add a early check, returning
> EFI_ACCESS_DENIED when File is NULL.
> 
> Noticed while reviewing commit 6d57592740cdd0b6868baeef7929d6e6fef.
> 
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Chao Zhang <chao.b.zhang@intel.com>
> Signed-off-by: Philippe Mathieu-Daude <philmd@redhat.com>
> ---
>  .../DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.c        | 9 ++++++++-
>  .../Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c  | 9 ++++++++-
>  2 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.c b/SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.c
> index 04b9b0d7fbf3..cabc0c6c7556 100644
> --- a/SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.c
> +++ b/SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.c
> @@ -384,7 +384,7 @@ Tcg2MeasurePeImage (
>    and other exception operations.  The File parameter allows for possible logging
>    within the SAP of the driver.
>  
> -  If File is NULL, then EFI_INVALID_PARAMETER is returned.
> +  If File is NULL, then EFI_ACCESS_DENIED is returned.
>  
>    If the file specified by File with an authentication status specified by
>    AuthenticationStatus is safe for the DXE Core to use, then EFI_SUCCESS is returned.
> @@ -435,6 +435,13 @@ DxeTpm2MeasureBootHandler (
>    EFI_PHYSICAL_ADDRESS                FvAddress;
>    UINT32                              Index;
>  
> +  //
> +  // Check for invalid parameters.
> +  //
> +  if (File == NULL) {
> +    return EFI_ACCESS_DENIED;
> +  }
> +
>    Status = gBS->LocateProtocol (&gEfiTcg2ProtocolGuid, NULL, (VOID **) &Tcg2Protocol);
>    if (EFI_ERROR (Status)) {
>      //
> diff --git a/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c b/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c
> index 1f2eed29a1df..dfaaa0f0b332 100644
> --- a/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c
> +++ b/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c
> @@ -678,7 +678,7 @@ TcgMeasurePeImage (
>    and other exception operations.  The File parameter allows for possible logging
>    within the SAP of the driver.
>  
> -  If File is NULL, then EFI_INVALID_PARAMETER is returned.
> +  If File is NULL, then EFI_ACCESS_DENIED is returned.
>  
>    If the file specified by File with an authentication status specified by
>    AuthenticationStatus is safe for the DXE Core to use, then EFI_SUCCESS is returned.
> @@ -732,6 +732,13 @@ DxeTpmMeasureBootHandler (
>    EFI_PHYSICAL_ADDRESS                FvAddress;
>    UINT32                              Index;
>  
> +  //
> +  // Check for invalid parameters.
> +  //
> +  if (File == NULL) {
> +    return EFI_ACCESS_DENIED;
> +  }
> +
>    Status = gBS->LocateProtocol (&gEfiTcgProtocolGuid, NULL, (VOID **) &TcgProtocol);
>    if (EFI_ERROR (Status)) {
>      //
> 

Reviewed-by: Laszlo Ersek <lersek@redhat.com>