SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c

   1 /** @file
   2   RNG Driver to produce the UEFI Random Number Generator protocol.
   3
   4   The driver can use RNDR instruction (through the RngLib and if FEAT_RNG is
   5   present) to produce random numbers. It also uses the Arm FW-TRNG interface
   6   to implement EFI_RNG_ALGORITHM_RAW.
   7
   8   RNG Algorithms defined in UEFI 2.4:
   9    - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID
  10    - EFI_RNG_ALGORITHM_RAW
  11    - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID
  12    - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID
  13    - EFI_RNG_ALGORITHM_X9_31_3DES_GUID        - Unsupported
  14    - EFI_RNG_ALGORITHM_X9_31_AES_GUID         - Unsupported
  15
  16   Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
  17   Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
  18   (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
  19   Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
  20
  21   SPDX-License-Identifier: BSD-2-Clause-Patent
  22
  23 **/
  24
  25 #include <Library/BaseLib.h>
  26 #include <Library/BaseMemoryLib.h>
  27 #include <Library/DebugLib.h>
  28 #include <Library/MemoryAllocationLib.h>
  29 #include <Library/UefiBootServicesTableLib.h>
  30 #include <Library/RngLib.h>
  31 #include <Library/DebugLib.h>
  32 #include <Library/ArmTrngLib.h>
  33 #include <Protocol/Rng.h>
  34
  35 #include "RngDxeInternals.h"
  36
  37 // Maximum number of Rng algorithms.
  38 #define RNG_AVAILABLE_ALGO_MAX  2
  39
  40 /** Allocate and initialize mAvailableAlgoArray with the available
  41     Rng algorithms. Also update mAvailableAlgoArrayCount.
  42
  43   @retval EFI_SUCCESS             The function completed successfully.
  44   @retval EFI_OUT_OF_RESOURCES    Could not allocate memory.
  45 **/
  46 EFI_STATUS
  47 EFIAPI
  48 GetAvailableAlgorithms (
  49   VOID
  50   )
  51 {
  52   UINT64  DummyRand;
  53   UINT16  MajorRevision;
  54   UINT16  MinorRevision;
  55
  56   // Rng algorithms 2 times, one for the allocation, one to populate.
  57   mAvailableAlgoArray = AllocateZeroPool (RNG_AVAILABLE_ALGO_MAX);
  58   if (mAvailableAlgoArray == NULL) {
  59     return EFI_OUT_OF_RESOURCES;
  60   }
  61
  62   // Check RngGetBytes() before advertising PcdCpuRngSupportedAlgorithm.
  63   if (!EFI_ERROR (RngGetBytes (sizeof (DummyRand), (UINT8 *)&DummyRand))) {
  64     CopyMem (
  65       &mAvailableAlgoArray[mAvailableAlgoArrayCount],
  66       PcdGetPtr (PcdCpuRngSupportedAlgorithm),
  67       sizeof (EFI_RNG_ALGORITHM)
  68       );
  69     mAvailableAlgoArrayCount++;
  70
  71     DEBUG_CODE_BEGIN ();
  72     if (IsZeroGuid (PcdGetPtr (PcdCpuRngSupportedAlgorithm))) {
  73       DEBUG ((
  74         DEBUG_WARN,
  75         "PcdCpuRngSupportedAlgorithm should be a non-zero GUID\n"
  76         ));
  77     }
  78
  79     DEBUG_CODE_END ();
  80   }
  81
  82   // Raw algorithm (Trng)
  83   if (!EFI_ERROR (GetArmTrngVersion (&MajorRevision, &MinorRevision))) {
  84     CopyMem (
  85       &mAvailableAlgoArray[mAvailableAlgoArrayCount],
  86       &gEfiRngAlgorithmRaw,
  87       sizeof (EFI_RNG_ALGORITHM)
  88       );
  89     mAvailableAlgoArrayCount++;
  90   }
  91
  92   return EFI_SUCCESS;
  93 }
  94
  95 /** Free mAvailableAlgoArray.
  96 **/
  97 VOID
  98 EFIAPI
  99 FreeAvailableAlgorithms (
 100   VOID
 101   )
 102 {
 103   FreePool (mAvailableAlgoArray);
 104   return;
 105 }
 106
 107 /**
 108   Produces and returns an RNG value using either the default or specified RNG algorithm.
 109
 110   @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL instance.
 111   @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that identifies the RNG
 112                                       algorithm to use. May be NULL in which case the function will
 113                                       use its default RNG algorithm.
 114   @param[in]  RNGValueLength          The length in bytes of the memory buffer pointed to by
 115                                       RNGValue. The driver shall return exactly this numbers of bytes.
 116   @param[out] RNGValue                A caller-allocated memory buffer filled by the driver with the
 117                                       resulting RNG value.
 118
 119   @retval EFI_SUCCESS                 The RNG value was returned successfully.
 120   @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm is not supported by
 121                                       this driver.
 122   @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due to a hardware or
 123                                       firmware error.
 124   @retval EFI_NOT_READY               There is not enough random data available to satisfy the length
 125                                       requested by RNGValueLength.
 126   @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is zero.
 127
 128 **/
 129 EFI_STATUS
 130 EFIAPI
 131 RngGetRNG (
 132   IN EFI_RNG_PROTOCOL   *This,
 133   IN EFI_RNG_ALGORITHM  *RNGAlgorithm  OPTIONAL,
 134   IN UINTN              RNGValueLength,
 135   OUT UINT8             *RNGValue
 136   )
 137 {
 138   EFI_STATUS  Status;
 139   UINTN       Index;
 140
 141   if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) {
 142     return EFI_INVALID_PARAMETER;
 143   }
 144
 145   if (RNGAlgorithm == NULL) {
 146     //
 147     // Use the default RNG algorithm if RNGAlgorithm is NULL.
 148     //
 149     for (Index = 0; Index < mAvailableAlgoArrayCount; Index++) {
 150       if (!IsZeroGuid (&mAvailableAlgoArray[Index])) {
 151         RNGAlgorithm = &mAvailableAlgoArray[Index];
 152         goto FoundAlgo;
 153       }
 154     }
 155
 156     if (Index == mAvailableAlgoArrayCount) {
 157       // No algorithm available.
 158       ASSERT (Index != mAvailableAlgoArrayCount);
 159       return EFI_DEVICE_ERROR;
 160     }
 161   }
 162
 163 FoundAlgo:
 164   if (CompareGuid (RNGAlgorithm, PcdGetPtr (PcdCpuRngSupportedAlgorithm))) {
 165     Status = RngGetBytes (RNGValueLength, RNGValue);
 166     return Status;
 167   }
 168
 169   // Raw algorithm (Trng)
 170   if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {
 171     return GenerateEntropy (RNGValueLength, RNGValue);
 172   }
 173
 174   //
 175   // Other algorithms are unsupported by this driver.
 176   //
 177   return EFI_UNSUPPORTED;
 178 }
 179
 180 /**
 181   Returns information about the random number generation implementation.
 182
 183   @param[in]     This                 A pointer to the EFI_RNG_PROTOCOL instance.
 184   @param[in,out] RNGAlgorithmListSize On input, the size in bytes of RNGAlgorithmList.
 185                                       On output with a return code of EFI_SUCCESS, the size
 186                                       in bytes of the data returned in RNGAlgorithmList. On output
 187                                       with a return code of EFI_BUFFER_TOO_SMALL,
 188                                       the size of RNGAlgorithmList required to obtain the list.
 189   @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled by the driver
 190                                       with one EFI_RNG_ALGORITHM element for each supported
 191                                       RNG algorithm. The list must not change across multiple
 192                                       calls to the same driver. The first algorithm in the list
 193                                       is the default algorithm for the driver.
 194
 195   @retval EFI_SUCCESS                 The RNG algorithm list was returned successfully.
 196   @retval EFI_UNSUPPORTED             The services is not supported by this driver.
 197   @retval EFI_DEVICE_ERROR            The list of algorithms could not be retrieved due to a
 198                                       hardware or firmware error.
 199   @retval EFI_INVALID_PARAMETER       One or more of the parameters are incorrect.
 200   @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small to hold the result.
 201
 202 **/
 203 EFI_STATUS
 204 EFIAPI
 205 RngGetInfo (
 206   IN EFI_RNG_PROTOCOL    *This,
 207   IN OUT UINTN           *RNGAlgorithmListSize,
 208   OUT EFI_RNG_ALGORITHM  *RNGAlgorithmList
 209   )
 210 {
 211   UINTN  RequiredSize;
 212
 213   if ((This == NULL) || (RNGAlgorithmListSize == NULL)) {
 214     return EFI_INVALID_PARAMETER;
 215   }
 216
 217   RequiredSize = mAvailableAlgoArrayCount * sizeof (EFI_RNG_ALGORITHM);
 218
 219   if (RequiredSize == 0) {
 220     // No supported algorithms found.
 221     return EFI_UNSUPPORTED;
 222   }
 223
 224   if (*RNGAlgorithmListSize < RequiredSize) {
 225     *RNGAlgorithmListSize = RequiredSize;
 226     return EFI_BUFFER_TOO_SMALL;
 227   }
 228
 229   if (RNGAlgorithmList == NULL) {
 230     return EFI_INVALID_PARAMETER;
 231   }
 232
 233   // There is no gap in the array, so copy the block.
 234   CopyMem (RNGAlgorithmList, mAvailableAlgoArray, RequiredSize);
 235   *RNGAlgorithmListSize = RequiredSize;
 236   return EFI_SUCCESS;
 237 }