Re: [edk2-devel] [PATCH v8 06/19] MdePkg/TrngLib: Definition for TRNG library class interface

["Yao, Jiewen" <jiewen.yao@intel.com>]

Hi 
This API is very ARM platform specific.

I don't see any interface like GetVersion or GetUUID is defined in 800-90A/90B/90C. 
What it is following is "Arm True Random Number Generator Firmware, Interface 1.0". As such, I feel uncomfortable to define TrngLib in MdePkg.

I have raised my concern before. My recommend is to move ArmPkg, for example ArmTrngLib.



Thank you
Yao Jiewen


> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> PierreGondois
> Sent: Tuesday, October 18, 2022 9:21 PM
> To: devel@edk2.groups.io
> Cc: Sami Mujawar <sami.mujawar@arm.com>; Leif Lindholm
> <quic_llindhol@quicinc.com>; Ard Biesheuvel
> <ardb+tianocore@kernel.org>; Rebecca Cran <rebecca@bsdio.com>; Kinney,
> Michael D <michael.d.kinney@intel.com>; Gao, Liming
> <gaoliming@byosoft.com.cn>; Yao, Jiewen <jiewen.yao@intel.com>; Wang,
> Jian J <jian.j.wang@intel.com>
> Subject: [edk2-devel] [PATCH v8 06/19] MdePkg/TrngLib: Definition for
> TRNG library class interface
> 
> From: Sami Mujawar <sami.mujawar@arm.com>
> 
> Bugzilla: 3668 (https://bugzilla.tianocore.org/show_bug.cgi?id=3668)
> 
> The NIST Special Publications 800-90A, 800-90B and 800-90C
> provide recommendations for random number generation. The
> NIST 800-90C, Recommendation for Random Bit Generator (RBG)
> Constructions, defines the GetEntropy() interface that is
> used to access the entropy source. The GetEntropy() interface
> is further used by Deterministic Random Bit Generators (DRBG)
> to generate random numbers.
> 
> The True Random Number Generator (TRNG) library defines an
> interface to access the entropy source on a platform. Some
> platforms/architectures may provide access to the entropy
> using a firmware interface. In such cases the TRNG library
> shall be used to provide an abstraction.
> 
> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> ---
>  MdePkg/Include/Library/TrngLib.h | 103
> +++++++++++++++++++++++++++++++
>  MdePkg/MdePkg.dec                |   5 ++
>  2 files changed, 108 insertions(+)
>  create mode 100644 MdePkg/Include/Library/TrngLib.h
> 
> diff --git a/MdePkg/Include/Library/TrngLib.h
> b/MdePkg/Include/Library/TrngLib.h
> new file mode 100644
> index 000000000000..535fd53f4305
> --- /dev/null
> +++ b/MdePkg/Include/Library/TrngLib.h
> @@ -0,0 +1,103 @@
> +/** @file
> +  TRNG interface library definitions.
> +
> +  Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +  @par Reference(s):
> +  - [1] NIST Special Publication 800-90B, Recommendation for the Entropy
> +        Sources Used for Random Bit Generation.
> +        (https://csrc.nist.gov/publications/detail/sp/800-90b/final)
> +
> +  @par Glossary:
> +    - TRNG - True Random Number Generator
> +**/
> +
> +#ifndef TRNG_LIB_H_
> +#define TRNG_LIB_H_
> +
> +/** Get the version of the TRNG backend.
> +
> +  A TRNG may be implemented by the system firmware, in which case this
> +  function shall return the version of the TRNG backend.
> +  The implementation must return NOT_SUPPORTED if a Back end is not
> present.
> +
> +  @param [out]  MajorRevision     Major revision.
> +  @param [out]  MinorRevision     Minor revision.
> +
> +  @retval  RETURN_SUCCESS            The function completed successfully.
> +  @retval  RETURN_INVALID_PARAMETER  Invalid parameter.
> +  @retval  RETURN_UNSUPPORTED        Backend not present.
> +**/
> +RETURN_STATUS
> +EFIAPI
> +GetTrngVersion (
> +  OUT UINT16  *MajorRevision,
> +  OUT UINT16  *MinorRevision
> +  );
> +
> +/** Get the UUID of the TRNG backend.
> +
> +  A TRNG may be implemented by the system firmware, in which case this
> +  function shall return the UUID of the TRNG backend.
> +  Returning the TRNG UUID is optional and if not implemented,
> RETURN_UNSUPPORTED
> +  shall be returned.
> +
> +  Note: The caller must not rely on the returned UUID as a trustworthy
> TRNG
> +        Back end identity
> +
> +  @param [out]  Guid              UUID of the TRNG backend.
> +
> +  @retval  RETURN_SUCCESS            The function completed successfully.
> +  @retval  RETURN_INVALID_PARAMETER  Invalid parameter.
> +  @retval  RETURN_UNSUPPORTED        Function not implemented.
> +**/
> +RETURN_STATUS
> +EFIAPI
> +GetTrngUuid (
> +  OUT GUID  *Guid
> +  );
> +
> +/** Returns maximum number of entropy bits that can be returned in a
> single
> +    call.
> +
> +  @return Returns the maximum number of Entropy bits that can be
> returned
> +          in a single call to GetTrngEntropy().
> +**/
> +UINTN
> +EFIAPI
> +GetTrngMaxSupportedEntropyBits (
> +  VOID
> +  );
> +
> +/** Returns N bits of conditioned entropy.
> +
> +  See [1] Section 2.3.1 GetEntropy: An Interface to the Entropy Source
> +    GetEntropy
> +      Input:
> +        bits_of_entropy: the requested amount of entropy
> +      Output:
> +        entropy_bitstring: The string that provides the requested entropy.
> +      status: A Boolean value that is TRUE if the request has been satisfied,
> +              and is FALSE otherwise.
> +
> +  @param  [in]   EntropyBits  Number of entropy bits requested.
> +  @param  [in]   BufferSize   Size of the Buffer in bytes.
> +  @param  [out]  Buffer       Buffer to return the entropy bits.
> +
> +  @retval  RETURN_SUCCESS            The function completed successfully.
> +  @retval  RETURN_INVALID_PARAMETER  Invalid parameter.
> +  @retval  RETURN_UNSUPPORTED        Function not implemented.
> +  @retval  RETURN_BAD_BUFFER_SIZE    Buffer size is too small.
> +  @retval  RETURN_NOT_READY          No Entropy available.
> +**/
> +RETURN_STATUS
> +EFIAPI
> +GetTrngEntropy (
> +  IN  UINTN  EntropyBits,
> +  IN  UINTN  BufferSize,
> +  OUT UINT8  *Buffer
> +  );
> +
> +#endif // TRNG_LIB_H_
> diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
> index 4c81cbd75ab2..0a7859fc1d3f 100644
> --- a/MdePkg/MdePkg.dec
> +++ b/MdePkg/MdePkg.dec
> @@ -8,6 +8,7 @@
>  # Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
>  # (C) Copyright 2016 - 2021 Hewlett Packard Enterprise Development
> LP<BR>
>  # Copyright (c) 2022, Loongson Technology Corporation Limited. All rights
> reserved.<BR>
> +# Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
>  #
>  # SPDX-License-Identifier: BSD-2-Clause-Patent
>  #
> @@ -279,6 +280,10 @@ [LibraryClasses]
>    ## @libraryclass  Provides function for SMM CPU Rendezvous Library.
>    SmmCpuRendezvousLib|Include/Library/SmmCpuRendezvousLib.h
> 
> +  ##  @libraryclass  Provides services to generate Entropy using a TRNG.
> +  #
> +  TrngLib|Include/Library/TrngLib.h
> +
>  [LibraryClasses.IA32, LibraryClasses.X64, LibraryClasses.AARCH64]
>    ##  @libraryclass  Provides services to generate random number.
>    #
> --
> 2.25.1
> 
> 
> 
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