SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c

   1 /** @file
   2   RNG Driver to produce the UEFI Random Number Generator protocol.
   3
   4   The driver uses CPU RNG instructions to produce high-quality,
   5   high-performance entropy and random number.
   6
   7   RNG Algorithms defined in UEFI 2.4:
   8    - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID
   9    - EFI_RNG_ALGORITHM_RAW
  10    - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID
  11    - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID
  12    - EFI_RNG_ALGORITHM_X9_31_3DES_GUID
  13    - EFI_RNG_ALGORITHM_X9_31_AES_GUID
  14
  15 Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
  16 (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
  17
  18 SPDX-License-Identifier: BSD-2-Clause-Patent
  19
  20 **/
  21
  22 #include <Library/BaseLib.h>
  23 #include <Library/BaseMemoryLib.h>
  24 #include <Library/UefiBootServicesTableLib.h>
  25 #include <Library/RngLib.h>
  26 #include <Protocol/Rng.h>
  27
  28 #include "RngDxeInternals.h"
  29
  30 //
  31 // The Random Number Generator (RNG) protocol
  32 //
  33 EFI_RNG_PROTOCOL  mRngRdRand = {
  34   RngGetInfo,
  35   RngGetRNG
  36 };
  37
  38 /**
  39   The user Entry Point for the Random Number Generator (RNG) driver.
  40
  41   @param[in] ImageHandle    The firmware allocated handle for the EFI image.
  42   @param[in] SystemTable    A pointer to the EFI System Table.
  43
  44   @retval EFI_SUCCESS       The entry point is executed successfully.
  45   @retval EFI_NOT_SUPPORTED Platform does not support RNG.
  46   @retval Other             Some error occurs when executing this entry point.
  47
  48 **/
  49 EFI_STATUS
  50 EFIAPI
  51 RngDriverEntry (
  52   IN EFI_HANDLE        ImageHandle,
  53   IN EFI_SYSTEM_TABLE  *SystemTable
  54   )
  55 {
  56   EFI_STATUS  Status;
  57   EFI_HANDLE  Handle;
  58
  59   //
  60   // Install UEFI RNG (Random Number Generator) Protocol
  61   //
  62   Handle = NULL;
  63   Status = gBS->InstallMultipleProtocolInterfaces (
  64                   &Handle,
  65                   &gEfiRngProtocolGuid,
  66                   &mRngRdRand,
  67                   NULL
  68                   );
  69
  70   return Status;
  71 }
  72
  73 /**
  74   Runs CPU RNG instruction to fill a buffer of arbitrary size with random bytes.
  75
  76   @param[in]   Length        Size of the buffer, in bytes,  to fill with.
  77   @param[out]  RandBuffer    Pointer to the buffer to store the random result.
  78
  79   @retval EFI_SUCCESS        Random bytes generation succeeded.
  80   @retval EFI_NOT_READY      Failed to request random bytes.
  81
  82 **/
  83 EFI_STATUS
  84 EFIAPI
  85 RngGetBytes (
  86   IN UINTN   Length,
  87   OUT UINT8  *RandBuffer
  88   )
  89 {
  90   BOOLEAN  IsRandom;
  91   UINT64   TempRand[2];
  92
  93   while (Length > 0) {
  94     IsRandom = GetRandomNumber128 (TempRand);
  95     if (!IsRandom) {
  96       return EFI_NOT_READY;
  97     }
  98
  99     if (Length >= sizeof (TempRand)) {
 100       WriteUnaligned64 ((UINT64 *)RandBuffer, TempRand[0]);
 101       RandBuffer += sizeof (UINT64);
 102       WriteUnaligned64 ((UINT64 *)RandBuffer, TempRand[1]);
 103       RandBuffer += sizeof (UINT64);
 104       Length     -= sizeof (TempRand);
 105     } else {
 106       CopyMem (RandBuffer, TempRand, Length);
 107       Length = 0;
 108     }
 109   }
 110
 111   return EFI_SUCCESS;
 112 }