Re: [PATCH] MdeModulePkg/Partition: Fix media probe

["Wang, Jian J" <jian.j.wang@intel.com>]

Tested-by/Reviewed-by: Jian J Wang <jian.j.wang@intel.com>

> -----Original Message-----
> From: Ni, Ruiyu
> Sent: Thursday, January 25, 2018 5:45 PM
> To: edk2-devel@lists.01.org
> Cc: Wang, Jian J <jian.j.wang@intel.com>
> Subject: [PATCH] MdeModulePkg/Partition: Fix media probe
> 
> The call in ProbeMediaStatusEx() to the ReadDisk() function of the
> EFI_DISK_IO_PROTOCOL interface implemented in DiskIoDxe/DiskIo.c
> crashed in DiskIo2ReadWriteDisk() because of the NULL value of
> the destination buffer pointer.
> 
> Pass the address of a buffer in the stack instead of a NULL
> pointer.
> 
> The similar fix was applied to ProbeMediaStatus in commit
> df473cc1fc9acd1a623ec7e05276f2f0635c19d2
> * MdeModulePkg/PartitionDxe: Fix media probe
> 
> Somehow ProbeMediaStatusEx() wasn't changed together.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> ---
>  MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c
> b/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c
> index bb9d0b70ce..46c0877cee 100644
> --- a/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c
> +++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c
> @@ -4,7 +4,7 @@
>    of the raw block devices media. Currently "El Torito CD-ROM", UDF, Legacy
>    MBR, and GPT partition schemes are supported.
> 
> -Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2006 - 2018, 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
> @@ -777,11 +777,15 @@ ProbeMediaStatusEx (
>    )
>  {
>    EFI_STATUS                 Status;
> +  UINT8                      Buffer[1];
> 
>    //
> -  // Read 1 byte from offset 0 but passing NULL as buffer pointer
> +  // Read 1 byte from offset 0 to check if the MediaId is still valid.
> +  // The reading operation is synchronious thus it is not worth it to
> +  // allocate a buffer from the pool. The destination buffer for the
> +  // data is in the stack.
>    //
> -  Status = DiskIo2->ReadDiskEx (DiskIo2, MediaId, 0, NULL, 1, NULL);
> +  Status = DiskIo2->ReadDiskEx (DiskIo2, MediaId, 0, NULL, 1, (VOID*)Buffer);
>    if ((Status == EFI_NO_MEDIA) || (Status == EFI_MEDIA_CHANGED)) {
>      return Status;
>    }
> --
> 2.15.1.windows.2