Re: [PATCH v5 06/21] MdePkg/TrngLib: Add NULL instance of TRNG Library

["Leif Lindholm" <quic_llindhol@quicinc.com>]

On 2022-09-19 12:21, Pierre.Gondois@arm.com wrote:
> From: Sami Mujawar <sami.mujawar@arm.com>
> 
> Bugzilla: 3668 (https://bugzilla.tianocore.org/show_bug.cgi?id=3668)
> 
> The True Random Number Generator (TRNG) library defines an
> interface to access the entropy source on a platform. On
> platforms that do not have access to an entropy source, a
> NULL instance of the TRNG library may be useful to satisfy
> the build dependency.
> 
> Therefore, add a NULL instance of the TRNG library.
> 
> Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>

The patch needs to be signed off by the contributor (you), and no one 
else. You cannot make legal statements on their behalf, and you must 
make the statement on your own behalf.

> ---
>   .../Library/BaseTrngLibNull/BaseTrngLibNull.c | 117 ++++++++++++++++++
>   .../BaseTrngLibNull/BaseTrngLibNull.inf       |  30 +++++
>   .../BaseTrngLibNull/BaseTrngLibNull.uni       |  12 ++
>   MdePkg/MdePkg.dsc                             |   1 +
>   4 files changed, 160 insertions(+)
>   create mode 100644 MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.c
>   create mode 100644 MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.inf
>   create mode 100644 MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.uni
> 
> diff --git a/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.c b/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.c
> new file mode 100644
> index 000000000000..60774b33dd58
> --- /dev/null
> +++ b/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.c
> @@ -0,0 +1,117 @@
> +/** @file
> +  Null version of TRNG (True Random Number Generator) services.
> +
> +  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
> +**/
> +
> +#include <Library/DebugLib.h>
> +#include <Library/TrngLib.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
> +  )
> +{
> +  ASSERT (FALSE);
> +  return RETURN_UNSUPPORTED;
> +}
> +
> +/** 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
> +  )
> +{
> +  ASSERT (FALSE);
> +  return RETURN_UNSUPPORTED;
> +}
> +
> +/** 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
> +  )
> +{
> +  ASSERT (FALSE);
> +  return 0;
> +}
> +
> +/** 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
> +  )
> +{
> +  ASSERT (FALSE);
> +  return RETURN_UNSUPPORTED;
> +}
> diff --git a/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.inf b/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.inf
> new file mode 100644
> index 000000000000..004aa8445a25
> --- /dev/null
> +++ b/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.inf
> @@ -0,0 +1,30 @@
> +## @file
> +#  Null instance of TRNG (True Random Number Generator) Library.
> +#
> +#  Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001B
> +  BASE_NAME                      = BaseTrngLibNull
> +  MODULE_UNI_FILE                = BaseTrngLibNull.uni
> +  FILE_GUID                      = ABDE1C87-4F50-4B82-9133-7A79E13F69AB
> +  MODULE_TYPE                    = BASE
> +  VERSION_STRING                 = 1.0
> +  LIBRARY_CLASS                  = TrngLib
> +
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64 ARM AARCH64

RISCV64?

> +#
> +
> +[Sources]
> +  BaseTrngLibNull.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +
> +[LibraryClasses]
> +  DebugLib
> diff --git a/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.uni b/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.uni
> new file mode 100644
> index 000000000000..952e4354c0cc
> --- /dev/null
> +++ b/MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.uni
> @@ -0,0 +1,12 @@
> +// /** @file
> +// Null Instance of TRNG (True Random Number Generator) Library.
> +//
> +//  Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +#string STR_MODULE_ABSTRACT             #language en-US "Null instance of TRNG Library"
> +
> +#string STR_MODULE_DESCRIPTION          #language en-US "This library instance should be used with modules that inherit an (indirect) dependency on the TrngLib class, but never actually call TrngLib APIs for consuming Entropy."
> diff --git a/MdePkg/MdePkg.dsc b/MdePkg/MdePkg.dsc
> index cc1ac196a931..1a3a3c3243f5 100644
> --- a/MdePkg/MdePkg.dsc
> +++ b/MdePkg/MdePkg.dsc
> @@ -67,6 +67,7 @@ [Components]
>     MdePkg/Library/DxeRngLib/DxeRngLib.inf
>     MdePkg/Library/BaseRngLibNull/BaseRngLibNull.inf
>     MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf
> +  MdePkg/Library/BaseTrngLibNull/BaseTrngLibNull.inf

Indentation?

/
     Leif

>   
>     MdePkg/Library/BaseSerialPortLibNull/BaseSerialPortLibNull.inf
>     MdePkg/Library/BaseSynchronizationLib/BaseSynchronizationLib.inf