Re: [edk2-devel] [PATCH 1/2] SecurityPkg: Add RNG support

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

Some comment:

1) Please note that global variable is not allowed in BaseLib.
+STATIC BOOLEAN  mHasRdRand;

2) We already have https://github.com/tianocore/edk2/tree/master/MdePkg/Library/BaseRngLib
Why we need another BaseRngLib ?


> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Sean
> Rhodes
> Sent: Thursday, February 24, 2022 6:44 AM
> To: devel@edk2.groups.io
> Cc: Dong, Guo <guo.dong@intel.com>; Patrick Rudolph
> <patrick.rudolph@9elements.com>; Yao, Jiewen <jiewen.yao@intel.com>;
> Wang, Jian J <jian.j.wang@intel.com>
> Subject: [edk2-devel] [PATCH 1/2] SecurityPkg: Add RNG support
> 
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> Uses the RDRAND instruction if available and install EfiRngProtocol.
> The protocol may be used by iPXE or the Linux kernel to gather entropy.
> 
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Guo Dong <guo.dong@intel.com>
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> ---
>  SecurityPkg/Library/BaseRngLib/BaseRng.c      | 199 ++++++++++++++++++
>  SecurityPkg/Library/BaseRngLib/BaseRngLib.inf |  32 +++
>  SecurityPkg/Library/BaseRngLib/BaseRngLib.uni |  17 ++
>  3 files changed, 248 insertions(+)
>  create mode 100644 SecurityPkg/Library/BaseRngLib/BaseRng.c
>  create mode 100644 SecurityPkg/Library/BaseRngLib/BaseRngLib.inf
>  create mode 100644 SecurityPkg/Library/BaseRngLib/BaseRngLib.uni
> 
> diff --git a/SecurityPkg/Library/BaseRngLib/BaseRng.c
> b/SecurityPkg/Library/BaseRngLib/BaseRng.c
> new file mode 100644
> index 0000000000..c21e713cb0
> --- /dev/null
> +++ b/SecurityPkg/Library/BaseRngLib/BaseRng.c
> @@ -0,0 +1,199 @@
> +/** @file
> 
> +  Random number generator services that uses RdRand instruction access
> 
> +  to provide high-quality random numbers.
> 
> +
> 
> +Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
> 
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> 
> +
> 
> +**/
> 
> +
> 
> +#include <Library/BaseLib.h>
> 
> +#include <Library/DebugLib.h>
> 
> +#include <Register/Intel/Cpuid.h>
> 
> +
> 
> +STATIC BOOLEAN  mHasRdRand;
> 
> +
> 
> +//
> 
> +// Bit mask used to determine if RdRand instruction is supported.
> 
> +//
> 
> +#define RDRAND_MASK  BIT30
> 
> +
> 
> +//
> 
> +// Limited retry number when valid random data is returned.
> 
> +// Uses the recommended value defined in Section 7.3.17 of "Intel 64 and IA-32
> 
> +// Architectures Software Developer's Mannual".
> 
> +//
> 
> +#define RDRAND_RETRY_LIMIT  10
> 
> +
> 
> +/**
> 
> +  The constructor function checks whether or not RDRAND instruction is
> supported
> 
> +  by the host hardware.
> 
> +
> 
> +  The constructor function checks whether or not RDRAND instruction is
> supported.
> 
> +  It will always return RETURN_SUCCESS.
> 
> +
> 
> +  @retval RETURN_SUCCESS   The constructor always returns EFI_SUCCESS.
> 
> +
> 
> +**/
> 
> +RETURN_STATUS
> 
> +EFIAPI
> 
> +BaseRngLibConstructor (
> 
> +  VOID
> 
> +  )
> 
> +{
> 
> +  UINT32  RegEax;
> 
> +  UINT32  RegEcx;
> 
> +
> 
> +  AsmCpuid (CPUID_SIGNATURE, &RegEax, NULL, NULL, NULL);
> 
> +  if (RegEax < 1) {
> 
> +    mHasRdRand = FALSE;
> 
> +    return RETURN_SUCCESS;
> 
> +  }
> 
> +
> 
> +  //
> 
> +  // Determine RDRAND support by examining bit 30 of the ECX register
> returned by
> 
> +  // CPUID. A value of 1 indicates that processor support RDRAND instruction.
> 
> +  //
> 
> +  AsmCpuid (CPUID_VERSION_INFO, 0, 0, &RegEcx, 0);
> 
> +
> 
> +  mHasRdRand = ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
> 
> +
> 
> +  return RETURN_SUCCESS;
> 
> +}
> 
> +
> 
> +/**
> 
> +  Generates a 16-bit random number.
> 
> +
> 
> +  if Rand is NULL, then ASSERT().
> 
> +
> 
> +  @param[out] Rand     Buffer pointer to store the 16-bit random value.
> 
> +
> 
> +  @retval TRUE         Random number generated successfully.
> 
> +  @retval FALSE        Failed to generate the random number.
> 
> +
> 
> +**/
> 
> +BOOLEAN
> 
> +EFIAPI
> 
> +GetRandomNumber16 (
> 
> +  OUT     UINT16  *Rand
> 
> +  )
> 
> +{
> 
> +  UINT32  Index;
> 
> +
> 
> +  ASSERT (Rand != NULL);
> 
> +
> 
> +  if (mHasRdRand) {
> 
> +    //
> 
> +    // A loop to fetch a 16 bit random value with a retry count limit.
> 
> +    //
> 
> +    for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
> 
> +      if (AsmRdRand16 (Rand)) {
> 
> +        return TRUE;
> 
> +      }
> 
> +    }
> 
> +  }
> 
> +
> 
> +  return FALSE;
> 
> +}
> 
> +
> 
> +/**
> 
> +  Generates a 32-bit random number.
> 
> +
> 
> +  if Rand is NULL, then ASSERT().
> 
> +
> 
> +  @param[out] Rand     Buffer pointer to store the 32-bit random value.
> 
> +
> 
> +  @retval TRUE         Random number generated successfully.
> 
> +  @retval FALSE        Failed to generate the random number.
> 
> +
> 
> +**/
> 
> +BOOLEAN
> 
> +EFIAPI
> 
> +GetRandomNumber32 (
> 
> +  OUT     UINT32  *Rand
> 
> +  )
> 
> +{
> 
> +  UINT32  Index;
> 
> +
> 
> +  ASSERT (Rand != NULL);
> 
> +
> 
> +  if (mHasRdRand) {
> 
> +    //
> 
> +    // A loop to fetch a 32 bit random value with a retry count limit.
> 
> +    //
> 
> +    for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
> 
> +      if (AsmRdRand32 (Rand)) {
> 
> +        return TRUE;
> 
> +      }
> 
> +    }
> 
> +  }
> 
> +
> 
> +  return FALSE;
> 
> +}
> 
> +
> 
> +/**
> 
> +  Generates a 64-bit random number.
> 
> +
> 
> +  if Rand is NULL, then ASSERT().
> 
> +
> 
> +  @param[out] Rand     Buffer pointer to store the 64-bit random value.
> 
> +
> 
> +  @retval TRUE         Random number generated successfully.
> 
> +  @retval FALSE        Failed to generate the random number.
> 
> +
> 
> +**/
> 
> +BOOLEAN
> 
> +EFIAPI
> 
> +GetRandomNumber64 (
> 
> +  OUT     UINT64  *Rand
> 
> +  )
> 
> +{
> 
> +  UINT32  Index;
> 
> +
> 
> +  ASSERT (Rand != NULL);
> 
> +
> 
> +  if (mHasRdRand) {
> 
> +    //
> 
> +    // A loop to fetch a 64 bit random value with a retry count limit.
> 
> +    //
> 
> +    for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
> 
> +      if (AsmRdRand64 (Rand)) {
> 
> +        return TRUE;
> 
> +      }
> 
> +    }
> 
> +  }
> 
> +
> 
> +  return FALSE;
> 
> +}
> 
> +
> 
> +/**
> 
> +  Generates a 128-bit random number.
> 
> +
> 
> +  if Rand is NULL, then ASSERT().
> 
> +
> 
> +  @param[out] Rand     Buffer pointer to store the 128-bit random value.
> 
> +
> 
> +  @retval TRUE         Random number generated successfully.
> 
> +  @retval FALSE        Failed to generate the random number.
> 
> +
> 
> +**/
> 
> +BOOLEAN
> 
> +EFIAPI
> 
> +GetRandomNumber128 (
> 
> +  OUT     UINT64  *Rand
> 
> +  )
> 
> +{
> 
> +  ASSERT (Rand != NULL);
> 
> +
> 
> +  //
> 
> +  // Read first 64 bits
> 
> +  //
> 
> +  if (!GetRandomNumber64 (Rand)) {
> 
> +    return FALSE;
> 
> +  }
> 
> +
> 
> +  //
> 
> +  // Read second 64 bits
> 
> +  //
> 
> +  return GetRandomNumber64 (++Rand);
> 
> +}
> 
> diff --git a/SecurityPkg/Library/BaseRngLib/BaseRngLib.inf
> b/SecurityPkg/Library/BaseRngLib/BaseRngLib.inf
> new file mode 100644
> index 0000000000..67a91ccfff
> --- /dev/null
> +++ b/SecurityPkg/Library/BaseRngLib/BaseRngLib.inf
> @@ -0,0 +1,32 @@
> +## @file
> 
> +#  Instance of RNG (Random Number Generator) Library.
> 
> +#
> 
> +#  Copyright (c) 2020 9elements Agency GmbH.<BR>
> 
> +#
> 
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> 
> +#
> 
> +##
> 
> +
> 
> +[Defines]
> 
> +  INF_VERSION                    = 0x00010005
> 
> +  BASE_NAME                      = BaseRngLib
> 
> +  MODULE_UNI_FILE                = BaseRngLib.uni
> 
> +  FILE_GUID                      = 05C48431-DE18-4550-931A-3350E8551498
> 
> +  MODULE_TYPE                    = BASE
> 
> +  VERSION_STRING                 = 1.0
> 
> +  LIBRARY_CLASS                  = RngLib
> 
> +  CONSTRUCTOR                    = BaseRngLibConstructor
> 
> +
> 
> +#
> 
> +#  VALID_ARCHITECTURES           = IA32 X64
> 
> +#
> 
> +
> 
> +[Sources.Ia32, Sources.X64]
> 
> +  BaseRng.c
> 
> +
> 
> +[Packages]
> 
> +  MdePkg/MdePkg.dec
> 
> +
> 
> +[LibraryClasses]
> 
> +  BaseLib
> 
> +  DebugLib
> 
> diff --git a/SecurityPkg/Library/BaseRngLib/BaseRngLib.uni
> b/SecurityPkg/Library/BaseRngLib/BaseRngLib.uni
> new file mode 100644
> index 0000000000..f3ed954c52
> --- /dev/null
> +++ b/SecurityPkg/Library/BaseRngLib/BaseRngLib.uni
> @@ -0,0 +1,17 @@
> +// /** @file
> 
> +// Instance of RNG (Random Number Generator) Library.
> 
> +//
> 
> +// BaseRng Library that uses CPU RdRand instruction access to provide
> 
> +// high-quality random numbers.
> 
> +//
> 
> +// Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
> 
> +//
> 
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> 
> +//
> 
> +// **/
> 
> +
> 
> +
> 
> +#string STR_MODULE_ABSTRACT             #language en-US "Instance of RNG
> Library"
> 
> +
> 
> +#string STR_MODULE_DESCRIPTION          #language en-US "BaseRng Library
> that uses CPU RdRand instruction access to provide high-quality random
> numbers"
> 
> +
> 
> --
> 2.32.0
> 
> 
> 
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