Re: [Patch 1/1] ShellPkg/Shell: Do not set end device path if already end

["Ard Biesheuvel" <ardb@kernel.org>]

On Fri, 9 Dec 2022 at 17:00, Michael D Kinney
<michael.d.kinney@intel.com> wrote:
>
> Update Shell Protocol EfiShellGetMapFromDevicePath() to not
> set the end if the device path if it is already an end of
> entire device path.  This removes a write oprtation that can
> cause failures if the Device Path Protocol is mapped to
> read-only memory.  In general Device Path Protocols should not
> be modified unless the API explicitly states that the device
> path is modified.
>
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Zhichao Gao <zhichao.gao@intel.com>
> Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  ShellPkg/Application/Shell/ShellProtocol.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/ShellPkg/Application/Shell/ShellProtocol.c b/ShellPkg/Application/Shell/ShellProtocol.c
> index 509eb60e40f4..e6d20ab16479 100644
> --- a/ShellPkg/Application/Shell/ShellProtocol.c
> +++ b/ShellPkg/Application/Shell/ShellProtocol.c
> @@ -294,7 +294,13 @@ EfiShellGetMapFromDevicePath (
>        *DevicePath = NextDevicePathNode (*DevicePath);
>      }
>
> -    SetDevicePathEndNode (*DevicePath);
> +    //
> +    // Do not call SetDevicePathEndNode() if the device path node is already the
> +    // end of an entire device path.
> +    //
> +    if (!IsDevicePathEnd (*DevicePath)) {
> +      SetDevicePathEndNode (*DevicePath);
> +    }
>    }
>
>    /*
> --
> 2.37.1.windows.1
>