Re: [PATCH v1 1/1] OvmfPkg/PlatformDxe: Handle all requests in ExtractConfig and RouteConfig

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

On Thu, 18 Aug 2022 at 21:58, Dimitrije Pavlov <dimitrije.pavlov@arm.com> wrote:
>
> Per the UEFI specification, if the Request argument in
> EFI_HII_CONFIG_ACCESS_PROTOCOL.ExtractConfig() is NULL or does not contain
> any request elements, the implementation should return all of the settings
> being abstracted for the particular ConfigHdr reference.
>
> The current implementation returns EFI_INVALID_PARAMETER if Request is
> NULL or does not contain any request elements. Instead, construct
> a new ConfigRequest to handle these cases per the specification.
>
> In addition, per the UEFI specification, if the Configuration argument in
> EFI_HII_CONFIG_ACCESS_PROTOCOL.RouteConfig() has a ConfigHdr that
> specifies a non-existing target, the implementation should return
> EFI_NOT_FOUND.
>
> The current implementation returns EFI_INVALID_PARAMETER if Configuration
> has a non-existing target in ConfigHdr. Instead, perform a check and
> return EFI_NOT_FOUND in this case.
>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> Cc: Sunny Wang <Sunny.Wang@arm.com>
> Cc: Jeff Booher-Kaeding <Jeff.Booher-Kaeding@arm.com>
> Cc: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
>
> Signed-off-by: Dimitrije Pavlov <Dimitrije.Pavlov@arm.com>

Was this issue caught in some kind of testing/validation?

> ---
>  OvmfPkg/PlatformDxe/PlatformConfig.h |   2 +
>  OvmfPkg/PlatformDxe/Platform.c       | 115 +++++++++++++++++++-
>  OvmfPkg/PlatformDxe/PlatformConfig.c |   2 +-
>  3 files changed, 116 insertions(+), 3 deletions(-)
>
> diff --git a/OvmfPkg/PlatformDxe/PlatformConfig.h b/OvmfPkg/PlatformDxe/PlatformConfig.h
> index 902c9b2ce043..5d9b457b1b4b 100644
> --- a/OvmfPkg/PlatformDxe/PlatformConfig.h
> +++ b/OvmfPkg/PlatformDxe/PlatformConfig.h
> @@ -50,4 +50,6 @@ PlatformConfigLoad (
>  #define PLATFORM_CONFIG_F_GRAPHICS_RESOLUTION  BIT0
>  #define PLATFORM_CONFIG_F_DOWNGRADE            BIT63
>
> +extern CHAR16  mVariableName[];
> +
>  #endif // _PLATFORM_CONFIG_H_
> diff --git a/OvmfPkg/PlatformDxe/Platform.c b/OvmfPkg/PlatformDxe/Platform.c
> index a6d459f3dfd7..0e32c6e76037 100644
> --- a/OvmfPkg/PlatformDxe/Platform.c
> +++ b/OvmfPkg/PlatformDxe/Platform.c
> @@ -108,6 +108,11 @@ STATIC EFI_EVENT  mGopEvent;
>  //
>  STATIC VOID  *mGopTracker;
>
> +//
> +// The driver image handle, used to obtain the device path for <ConfigHdr>.
> +//
> +STATIC EFI_HANDLE  mImageHandle;
> +
>  //
>  // Cache the resolutions we get from the GOP.
>  //
> @@ -229,6 +234,10 @@ ExtractConfig (
>  {
>    MAIN_FORM_STATE  MainFormState;
>    EFI_STATUS       Status;
> +  EFI_STRING       ConfigRequestHdr;
> +  EFI_STRING       ConfigRequest;
> +  UINTN            Size;
> +  BOOLEAN          AllocatedRequest;
>
>    DEBUG ((DEBUG_VERBOSE, "%a: Request=\"%s\"\n", __FUNCTION__, Request));
>
> @@ -236,18 +245,73 @@ ExtractConfig (
>      return EFI_INVALID_PARAMETER;
>    }
>
> +  ConfigRequestHdr = NULL;
> +  ConfigRequest    = NULL;
> +  Size             = 0;
> +  AllocatedRequest = FALSE;
> +
> +  //
> +  // Check if <ConfigHdr> matches the GUID and name
> +  //
> +  *Progress = Request;
> +  if ((Request != NULL) &&
> +      !HiiIsConfigHdrMatch (
> +         Request,
> +         &gOvmfPlatformConfigGuid,
> +         mVariableName
> +         )
> +      )
> +  {
> +    return EFI_NOT_FOUND;
> +  }
> +
>    Status = PlatformConfigToFormState (&MainFormState);
>    if (EFI_ERROR (Status)) {
> -    *Progress = Request;
>      return Status;
>    }
>
> +  if ((Request == NULL) || (StrStr (Request, L"OFFSET") == NULL)) {
> +    //
> +    // Request has no <RequestElement>, so construct full request string.
> +    // Allocate and fill a buffer large enough to hold <ConfigHdr>
> +    // followed by "&OFFSET=0&WIDTH=WWWWWWWWWWWWWWWW" followed by a
> +    // null terminator.
> +    //
> +    ConfigRequestHdr = HiiConstructConfigHdr (
> +                         &gOvmfPlatformConfigGuid,
> +                         mVariableName,
> +                         mImageHandle
> +                         );
> +    if (ConfigRequestHdr == NULL) {
> +      return EFI_OUT_OF_RESOURCES;
> +    }
> +
> +    Size             = (StrLen (ConfigRequestHdr) + 32 + 1) * sizeof (CHAR16);
> +    ConfigRequest    = AllocateZeroPool (Size);
> +    AllocatedRequest = TRUE;
> +    if (ConfigRequest == NULL) {
> +      FreePool (ConfigRequestHdr);
> +      return EFI_OUT_OF_RESOURCES;
> +    }
> +
> +    UnicodeSPrint (
> +      ConfigRequest,
> +      Size,
> +      L"%s&OFFSET=0&WIDTH=%016LX",
> +      ConfigRequestHdr,
> +      sizeof MainFormState
> +      );
> +    FreePool (ConfigRequestHdr);
> +  } else {
> +    ConfigRequest = Request;
> +  }
> +
>    //
>    // Answer the textual request keying off the binary form state.
>    //
>    Status = gHiiConfigRouting->BlockToConfig (
>                                  gHiiConfigRouting,
> -                                Request,
> +                                ConfigRequest,
>                                  (VOID *)&MainFormState,
>                                  sizeof MainFormState,
>                                  Results,
> @@ -265,6 +329,33 @@ ExtractConfig (
>      DEBUG ((DEBUG_VERBOSE, "%a: Results=\"%s\"\n", __FUNCTION__, *Results));
>    }
>
> +  //
> +  // If we used a newly allocated ConfigRequest, update Progress to point to
> +  // original Request instead of ConfigRequest.
> +  //
> +  if (Request == NULL) {
> +    *Progress = NULL;
> +  } else if (StrStr (Request, L"OFFSET") == NULL) {
> +    if (EFI_ERROR (Status)) {
> +      //
> +      // Since we constructed ConfigRequest, failure can only occur if there
> +      // is not enough memory. In this case, we point Progress to the first
> +      // character of Request.
> +      //
> +      *Progress = Request;
> +    } else {
> +      //
> +      // In case of success, we point Progress to the null terminator of
> +      // Request.
> +      //
> +      *Progress = Request + StrLen (Request);
> +    }
> +  }
> +
> +  if (AllocatedRequest) {
> +    FreePool (ConfigRequest);
> +  }
> +
>    return Status;
>  }
>
> @@ -348,6 +439,21 @@ RouteConfig (
>      return EFI_INVALID_PARAMETER;
>    }
>
> +  //
> +  // Check if <ConfigHdr> matches the GUID and name
> +  //
> +  *Progress = Configuration;
> +  if ((Configuration != NULL) &&
> +      !HiiIsConfigHdrMatch (
> +         Configuration,
> +         &gOvmfPlatformConfigGuid,
> +         mVariableName
> +         )
> +      )
> +  {
> +    return EFI_NOT_FOUND;
> +  }
> +
>    //
>    // the "read" step in RMW
>    //
> @@ -866,6 +972,11 @@ PlatformInit (
>      return Status;
>    }
>
> +  //
> +  // Save the driver image handle.
> +  //
> +  mImageHandle = ImageHandle;
> +
>    //
>    // Publish the HII package list to HII Database.
>    //
> diff --git a/OvmfPkg/PlatformDxe/PlatformConfig.c b/OvmfPkg/PlatformDxe/PlatformConfig.c
> index e202ac5b4798..f5ac2d0609ff 100644
> --- a/OvmfPkg/PlatformDxe/PlatformConfig.c
> +++ b/OvmfPkg/PlatformDxe/PlatformConfig.c
> @@ -21,7 +21,7 @@
>  //
>  // Name of the UEFI variable that we use for persistent storage.
>  //
> -STATIC CHAR16  mVariableName[] = L"PlatformConfig";
> +CHAR16  mVariableName[] = L"PlatformConfig";
>
>  /**
>    Serialize and persistently save platform configuration.
> --
> 2.37.2
>