SecurityPkg: Fix spelling errors

[mirror_edk2.git] / SecurityPkg / RandomNumberGenerator / RngDxe / RdRand.c

/** @file\r
  Support routines for RDRAND instruction access.\r
\r
Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>\r
(C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
#include <Library/RngLib.h>\r
\r
#include "RdRand.h"\r
#include "AesCore.h"\r
\r
/**\r
  Calls RDRAND to fill a buffer of arbitrary size with random bytes.\r
\r
  @param[in]   Length        Size of the buffer, in bytes,  to fill with.\r
  @param[out]  RandBuffer    Pointer to the buffer to store the random result.\r
\r
  @retval EFI_SUCCESS        Random bytes generation succeeded.\r
  @retval EFI_NOT_READY      Failed to request random bytes.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
RdRandGetBytes (\r
  IN UINTN         Length,\r
  OUT UINT8        *RandBuffer\r
  )\r
{\r
  BOOLEAN     IsRandom;\r
  UINT64      TempRand[2];\r
\r
  while (Length > 0) {\r
    IsRandom = GetRandomNumber128 (TempRand);\r
    if (!IsRandom) {\r
      return EFI_NOT_READY;\r
    }\r
    if (Length >= sizeof (TempRand)) {\r
      WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[0]);\r
      RandBuffer += sizeof (UINT64);\r
      WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[1]);\r
      RandBuffer += sizeof (UINT64);\r
      Length -= sizeof (TempRand);\r
    } else {\r
      CopyMem (RandBuffer, TempRand, Length);\r
      Length = 0;\r
    }\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Creates a 128bit random value that is fully forward and backward prediction resistant,\r
  suitable for seeding a NIST SP800-90 Compliant, FIPS 1402-2 certifiable SW DRBG.\r
  This function takes multiple random numbers through RDRAND without intervening\r
  delays to ensure reseeding and performs AES-CBC-MAC over the data to compute the\r
  seed value.\r
\r
  @param[out]  SeedBuffer    Pointer to a 128bit buffer to store the random seed.\r
\r
  @retval EFI_SUCCESS        Random seed generation succeeded.\r
  @retval EFI_NOT_READY      Failed to request random bytes.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
RdRandGetSeed128 (\r
  OUT UINT8        *SeedBuffer\r
  )\r
{\r
  EFI_STATUS  Status;\r
  UINT8       RandByte[16];\r
  UINT8       Key[16];\r
  UINT8       Ffv[16];\r
  UINT8       Xored[16];\r
  UINT32      Index;\r
  UINT32      Index2;\r
\r
  //\r
  // Chose an arbitrary key and zero the feed_forward_value (FFV)\r
  //\r
  for (Index = 0; Index < 16; Index++) {\r
    Key[Index] = (UINT8) Index;\r
    Ffv[Index] = 0;\r
  }\r
\r
  //\r
  // Perform CBC_MAC over 32 * 128 bit values, with 10us gaps between 128 bit value\r
  // The 10us gaps will ensure multiple reseeds within the HW RNG with a large design margin.\r
  //\r
  for (Index = 0; Index < 32; Index++) {\r
    MicroSecondDelay (10);\r
    Status = RdRandGetBytes (16, RandByte);\r
    if (EFI_ERROR (Status)) {\r
      return Status;\r
    }\r
\r
    //\r
    // Perform XOR operations on two 128-bit value.\r
    //\r
    for (Index2 = 0; Index2 < 16; Index2++) {\r
      Xored[Index2] = RandByte[Index2] ^ Ffv[Index2];\r
    }\r
\r
    AesEncrypt (Key, Xored, Ffv);\r
  }\r
\r
  for (Index = 0; Index < 16; Index++) {\r
    SeedBuffer[Index] = Ffv[Index];\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Generate high-quality entropy source through RDRAND.\r
\r
  @param[in]   Length        Size of the buffer, in bytes, to fill with.\r
  @param[out]  Entropy       Pointer to the buffer to store the entropy data.\r
\r
  @retval EFI_SUCCESS        Entropy generation succeeded.\r
  @retval EFI_NOT_READY      Failed to request random data.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
RdRandGenerateEntropy (\r
  IN UINTN         Length,\r
  OUT UINT8        *Entropy\r
  )\r
{\r
  EFI_STATUS  Status;\r
  UINTN       BlockCount;\r
  UINT8       Seed[16];\r
  UINT8       *Ptr;\r
\r
  Status     = EFI_NOT_READY;\r
  BlockCount = Length / 16;\r
  Ptr        = (UINT8 *)Entropy;\r
\r
  //\r
  // Generate high-quality seed for DRBG Entropy\r
  //\r
  while (BlockCount > 0) {\r
    Status = RdRandGetSeed128 (Seed);\r
    if (EFI_ERROR (Status)) {\r
      return Status;\r
    }\r
    CopyMem (Ptr, Seed, 16);\r
\r
    BlockCount--;\r
    Ptr = Ptr + 16;\r
  }\r
\r
  //\r
  // Populate the remained data as request.\r
  //\r
  Status = RdRandGetSeed128 (Seed);\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
  CopyMem (Ptr, Seed, (Length % 16));\r
\r
  return Status;\r
}\r