Re: [edk2-devel] [PATCH 1/2] MdeModulePkg: Remove the handle validation check in CoreGetProtocolInterface

["Michael D Kinney" <michael.d.kinney@intel.com>]

Hi Zhi,

Some comments below.

Mike

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Zhi Jin
> Sent: Tuesday, January 16, 2024 10:45 PM
> To: devel@edk2.groups.io
> Cc: Jin, Zhi <zhi.jin@intel.com>; Liming Gao <gaoliming@byosoft.com.cn>;
> Ni, Ray <ray.ni@intel.com>
> Subject: [edk2-devel] [PATCH 1/2] MdeModulePkg: Remove the handle
> validation check in CoreGetProtocolInterface
> 
> CoreGetProtocolInterface() is called by CoreOpenProtocol(),
> CoreCloseProtocol() and CoreOpenProtocolInformation().
> Before CoreOpenProtocol() calls CoreGetProtocolInterface(), the input
> parameter UserHandle has been already checked for validation. So does
> CoreCloseProtocol().
> Removing the handle validation check in CoreGetProtocolInterface()
> could improve the performance, as CoreOpenProtocol() is called very
> frequently.
> Meanwhile, need to make it the caller's responsibility to check the
> parameters, and add the check in CoreOpenProtocolInformation().
> 
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> Cc: Ray Ni <ray.ni@intel.com>
> Signed-off-by: Zhi Jin <zhi.jin@intel.com>
> ---
>  MdeModulePkg/Core/Dxe/Hand/Handle.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/MdeModulePkg/Core/Dxe/Hand/Handle.c
> b/MdeModulePkg/Core/Dxe/Hand/Handle.c
> index 51e5b5d3b3..a0d2d03267 100644
> --- a/MdeModulePkg/Core/Dxe/Hand/Handle.c
> +++ b/MdeModulePkg/Core/Dxe/Hand/Handle.c
> @@ -916,6 +916,8 @@ CoreUninstallMultipleProtocolInterfaces (
> 
>  /**
>    Locate a certain GUID protocol interface in a Handle's protocols.
> +  Note: This function doesn't do parameters checking, it's caller's
> responsibility
> +  to pass in valid parameters.
> 
>    @param  UserHandle             The handle to obtain the protocol
> interface on

Instead of a Note:, I recommend the description of this parameter
be updated to state that the caller must pass in a valid UserHandle
that is checked with CoreValidateHandle().

Also, this API CoreGetProtocolInterface() is an internal helper 
function.  I also recommend that this function be declared 'static'
so the scope of the assumption that UserHandle is valid is only 
by calls from other functions in this same file.

>    @param  Protocol               The GUID of the protocol
> @@ -929,17 +931,11 @@ CoreGetProtocolInterface (
>    IN  EFI_GUID    *Protocol
>    )
>  {
> -  EFI_STATUS          Status;
>    PROTOCOL_ENTRY      *ProtEntry;
>    PROTOCOL_INTERFACE  *Prot;
>    IHANDLE             *Handle;
>    LIST_ENTRY          *Link;
> 
> -  Status = CoreValidateHandle (UserHandle);
> -  if (EFI_ERROR (Status)) {
> -    return NULL;
> -  }
> -
>    Handle = (IHANDLE *)UserHandle;
> 
>    //
> @@ -1392,6 +1388,15 @@ CoreOpenProtocolInformation (
>    //
>    CoreAcquireProtocolLock ();
> 
> +  //
> +  // Check for invalid UserHandle
> +  //
> +  Status = CoreValidateHandle (UserHandle);
> +  if (EFI_ERROR (Status)) {
> +    Status = EFI_NOT_FOUND;
> +    goto Done;
> +  }
> +
>    //
>    // Look at each protocol interface for a match
>    //
> --
> 2.39.2
> 
> 
> 
> 
> 



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