SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c

   1 /** @file
   2   RNG Driver to produce the UEFI Random Number Generator protocol.
   3
   4   The driver will use the RNDR instruction to produce random numbers.
   5
   6   RNG Algorithms defined in UEFI 2.4:
   7    - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID
   8    - EFI_RNG_ALGORITHM_RAW                    - Unsupported
   9    - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID
  10    - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID
  11    - EFI_RNG_ALGORITHM_X9_31_3DES_GUID        - Unsupported
  12    - EFI_RNG_ALGORITHM_X9_31_AES_GUID         - Unsupported
  13
  14   Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
  15   Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
  16   (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
  17   Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
  18
  19   SPDX-License-Identifier: BSD-2-Clause-Patent
  20
  21 **/
  22
  23 #include <Library/BaseLib.h>
  24 #include <Library/BaseMemoryLib.h>
  25 #include <Library/UefiBootServicesTableLib.h>
  26 #include <Protocol/Rng.h>
  27
  28 #include "RngDxeInternals.h"
  29
  30 /**
  31   Produces and returns an RNG value using either the default or specified RNG algorithm.
  32
  33   @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL instance.
  34   @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that identifies the RNG
  35                                       algorithm to use. May be NULL in which case the function will
  36                                       use its default RNG algorithm.
  37   @param[in]  RNGValueLength          The length in bytes of the memory buffer pointed to by
  38                                       RNGValue. The driver shall return exactly this numbers of bytes.
  39   @param[out] RNGValue                A caller-allocated memory buffer filled by the driver with the
  40                                       resulting RNG value.
  41
  42   @retval EFI_SUCCESS                 The RNG value was returned successfully.
  43   @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm is not supported by
  44                                       this driver.
  45   @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due to a hardware or
  46                                       firmware error.
  47   @retval EFI_NOT_READY               There is not enough random data available to satisfy the length
  48                                       requested by RNGValueLength.
  49   @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is zero.
  50
  51 **/
  52 EFI_STATUS
  53 EFIAPI
  54 RngGetRNG (
  55   IN EFI_RNG_PROTOCOL   *This,
  56   IN EFI_RNG_ALGORITHM  *RNGAlgorithm  OPTIONAL,
  57   IN UINTN              RNGValueLength,
  58   OUT UINT8             *RNGValue
  59   )
  60 {
  61   EFI_STATUS  Status;
  62
  63   if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) {
  64     return EFI_INVALID_PARAMETER;
  65   }
  66
  67   if (RNGAlgorithm == NULL) {
  68     //
  69     // Use the default RNG algorithm if RNGAlgorithm is NULL.
  70     //
  71     RNGAlgorithm = PcdGetPtr (PcdCpuRngSupportedAlgorithm);
  72   }
  73
  74   if (CompareGuid (RNGAlgorithm, PcdGetPtr (PcdCpuRngSupportedAlgorithm))) {
  75     Status = RngGetBytes (RNGValueLength, RNGValue);
  76     return Status;
  77   }
  78
  79   //
  80   // Other algorithms are unsupported by this driver.
  81   //
  82   return EFI_UNSUPPORTED;
  83 }
  84
  85 /**
  86   Returns information about the random number generation implementation.
  87
  88   @param[in]     This                 A pointer to the EFI_RNG_PROTOCOL instance.
  89   @param[in,out] RNGAlgorithmListSize On input, the size in bytes of RNGAlgorithmList.
  90                                       On output with a return code of EFI_SUCCESS, the size
  91                                       in bytes of the data returned in RNGAlgorithmList. On output
  92                                       with a return code of EFI_BUFFER_TOO_SMALL,
  93                                       the size of RNGAlgorithmList required to obtain the list.
  94   @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled by the driver
  95                                       with one EFI_RNG_ALGORITHM element for each supported
  96                                       RNG algorithm. The list must not change across multiple
  97                                       calls to the same driver. The first algorithm in the list
  98                                       is the default algorithm for the driver.
  99
 100   @retval EFI_SUCCESS                 The RNG algorithm list was returned successfully.
 101   @retval EFI_UNSUPPORTED             The services is not supported by this driver.
 102   @retval EFI_DEVICE_ERROR            The list of algorithms could not be retrieved due to a
 103                                       hardware or firmware error.
 104   @retval EFI_INVALID_PARAMETER       One or more of the parameters are incorrect.
 105   @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small to hold the result.
 106
 107 **/
 108 EFI_STATUS
 109 EFIAPI
 110 RngGetInfo (
 111   IN EFI_RNG_PROTOCOL    *This,
 112   IN OUT UINTN           *RNGAlgorithmListSize,
 113   OUT EFI_RNG_ALGORITHM  *RNGAlgorithmList
 114   )
 115 {
 116   UINTN              RequiredSize;
 117   EFI_RNG_ALGORITHM  *CpuRngSupportedAlgorithm;
 118
 119   RequiredSize = sizeof (EFI_RNG_ALGORITHM);
 120
 121   if ((This == NULL) || (RNGAlgorithmListSize == NULL)) {
 122     return EFI_INVALID_PARAMETER;
 123   }
 124
 125   if (*RNGAlgorithmListSize < RequiredSize) {
 126     *RNGAlgorithmListSize = RequiredSize;
 127     return EFI_BUFFER_TOO_SMALL;
 128   }
 129
 130   CpuRngSupportedAlgorithm = PcdGetPtr (PcdCpuRngSupportedAlgorithm);
 131
 132   CopyMem (&RNGAlgorithmList[0], CpuRngSupportedAlgorithm, sizeof (EFI_RNG_ALGORITHM));
 133
 134   *RNGAlgorithmListSize = RequiredSize;
 135   return EFI_SUCCESS;
 136 }