SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c

   1 /** @file
   2   RNG Driver to produce the UEFI Random Number Generator protocol.
   3
   4   The driver will use the new RDRAND instruction to produce high-quality, high-performance
   5   entropy and random number.
   6
   7   RNG Algorithms defined in UEFI 2.4:
   8    - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID  - Supported
   9      (RDRAND implements a hardware NIST SP800-90 AES-CTR-256 based DRBG)
  10    - EFI_RNG_ALGORITHM_RAW                    - Supported
  11      (Structuring RDRAND invocation can be guaranteed as high-quality entropy source)
  12    - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID - Unsupported
  13    - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID - Unsupported
  14    - EFI_RNG_ALGORITHM_X9_31_3DES_GUID        - Unsupported
  15    - EFI_RNG_ALGORITHM_X9_31_AES_GUID         - Unsupported
  16
  17   Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
  18   Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
  19   (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
  20   SPDX-License-Identifier: BSD-2-Clause-Patent
  21
  22 **/
  23
  24 #include <Library/BaseLib.h>
  25 #include <Library/BaseMemoryLib.h>
  26
  27 #include "RngDxeInternals.h"
  28
  29 /** Allocate and initialize mAvailableAlgoArray with the available
  30     Rng algorithms. Also update mAvailableAlgoArrayCount.
  31
  32   @retval EFI_SUCCESS             The function completed successfully.
  33   @retval EFI_OUT_OF_RESOURCES    Could not allocate memory.
  34 **/
  35 EFI_STATUS
  36 EFIAPI
  37 GetAvailableAlgorithms (
  38   VOID
  39   )
  40 {
  41   return EFI_SUCCESS;
  42 }
  43
  44 /** Free mAvailableAlgoArray.
  45 **/
  46 VOID
  47 EFIAPI
  48 FreeAvailableAlgorithms (
  49   VOID
  50   )
  51 {
  52   return;
  53 }
  54
  55 /**
  56   Produces and returns an RNG value using either the default or specified RNG algorithm.
  57
  58   @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL instance.
  59   @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that identifies the RNG
  60                                       algorithm to use. May be NULL in which case the function will
  61                                       use its default RNG algorithm.
  62   @param[in]  RNGValueLength          The length in bytes of the memory buffer pointed to by
  63                                       RNGValue. The driver shall return exactly this numbers of bytes.
  64   @param[out] RNGValue                A caller-allocated memory buffer filled by the driver with the
  65                                       resulting RNG value.
  66
  67   @retval EFI_SUCCESS                 The RNG value was returned successfully.
  68   @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm is not supported by
  69                                       this driver.
  70   @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due to a hardware or
  71                                       firmware error.
  72   @retval EFI_NOT_READY               There is not enough random data available to satisfy the length
  73                                       requested by RNGValueLength.
  74   @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is zero.
  75
  76 **/
  77 EFI_STATUS
  78 EFIAPI
  79 RngGetRNG (
  80   IN EFI_RNG_PROTOCOL   *This,
  81   IN EFI_RNG_ALGORITHM  *RNGAlgorithm  OPTIONAL,
  82   IN UINTN              RNGValueLength,
  83   OUT UINT8             *RNGValue
  84   )
  85 {
  86   EFI_STATUS  Status;
  87
  88   if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) {
  89     return EFI_INVALID_PARAMETER;
  90   }
  91
  92   Status = EFI_UNSUPPORTED;
  93   if (RNGAlgorithm == NULL) {
  94     //
  95     // Use the default RNG algorithm if RNGAlgorithm is NULL.
  96     //
  97     RNGAlgorithm = &gEfiRngAlgorithmSp80090Ctr256Guid;
  98   }
  99
 100   //
 101   // NIST SP800-90-AES-CTR-256 supported by RDRAND
 102   //
 103   if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmSp80090Ctr256Guid)) {
 104     Status = RngGetBytes (RNGValueLength, RNGValue);
 105     return Status;
 106   }
 107
 108   //
 109   // The "raw" algorithm is intended to provide entropy directly
 110   //
 111   if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {
 112     //
 113     // When a DRBG is used on the output of a entropy source,
 114     // its security level must be at least 256 bits according to UEFI Spec.
 115     //
 116     if (RNGValueLength < 32) {
 117       return EFI_INVALID_PARAMETER;
 118     }
 119
 120     Status = GenerateEntropy (RNGValueLength, RNGValue);
 121     return Status;
 122   }
 123
 124   //
 125   // Other algorithms were unsupported by this driver.
 126   //
 127   return Status;
 128 }
 129
 130 /**
 131   Returns information about the random number generation implementation.
 132
 133   @param[in]     This                 A pointer to the EFI_RNG_PROTOCOL instance.
 134   @param[in,out] RNGAlgorithmListSize On input, the size in bytes of RNGAlgorithmList.
 135                                       On output with a return code of EFI_SUCCESS, the size
 136                                       in bytes of the data returned in RNGAlgorithmList. On output
 137                                       with a return code of EFI_BUFFER_TOO_SMALL,
 138                                       the size of RNGAlgorithmList required to obtain the list.
 139   @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled by the driver
 140                                       with one EFI_RNG_ALGORITHM element for each supported
 141                                       RNG algorithm. The list must not change across multiple
 142                                       calls to the same driver. The first algorithm in the list
 143                                       is the default algorithm for the driver.
 144
 145   @retval EFI_SUCCESS                 The RNG algorithm list was returned successfully.
 146   @retval EFI_UNSUPPORTED             No supported algorithms found.
 147   @retval EFI_DEVICE_ERROR            The list of algorithms could not be retrieved due to a
 148                                       hardware or firmware error.
 149   @retval EFI_INVALID_PARAMETER       One or more of the parameters are incorrect.
 150   @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small to hold the result.
 151
 152 **/
 153 EFI_STATUS
 154 EFIAPI
 155 RngGetInfo (
 156   IN EFI_RNG_PROTOCOL    *This,
 157   IN OUT UINTN           *RNGAlgorithmListSize,
 158   OUT EFI_RNG_ALGORITHM  *RNGAlgorithmList
 159   )
 160 {
 161   UINTN  RequiredSize;
 162
 163   if ((This == NULL) || (RNGAlgorithmListSize == NULL)) {
 164     return EFI_INVALID_PARAMETER;
 165   }
 166
 167   RequiredSize = 2 * sizeof (EFI_RNG_ALGORITHM);
 168
 169   if (*RNGAlgorithmListSize < RequiredSize) {
 170     *RNGAlgorithmListSize = RequiredSize;
 171     return EFI_BUFFER_TOO_SMALL;
 172   }
 173
 174   if (RNGAlgorithmList == NULL) {
 175     return EFI_INVALID_PARAMETER;
 176   }
 177
 178   CopyMem (&RNGAlgorithmList[0], &gEfiRngAlgorithmSp80090Ctr256Guid, sizeof (EFI_RNG_ALGORITHM));
 179
 180   // x86 platforms also support EFI_RNG_ALGORITHM_RAW via RDSEED
 181   CopyMem (&RNGAlgorithmList[1], &gEfiRngAlgorithmRaw, sizeof (EFI_RNG_ALGORITHM));
 182
 183   *RNGAlgorithmListSize = RequiredSize;
 184   return EFI_SUCCESS;
 185 }