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- /** @file
- RNG Driver to produce the UEFI Random Number Generator protocol.
- The driver can use RNDR instruction (through the RngLib and if FEAT_RNG is
- present) to produce random numbers. It also uses the Arm FW-TRNG interface
- to implement EFI_RNG_ALGORITHM_RAW.
- RNG Algorithms defined in UEFI 2.4:
- - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID
- - EFI_RNG_ALGORITHM_RAW
- - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID
- - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID
- - EFI_RNG_ALGORITHM_X9_31_3DES_GUID - Unsupported
- - EFI_RNG_ALGORITHM_X9_31_AES_GUID - Unsupported
- Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
- Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
- (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
- Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- **/
- #include <Library/BaseLib.h>
- #include <Library/BaseMemoryLib.h>
- #include <Library/DebugLib.h>
- #include <Library/MemoryAllocationLib.h>
- #include <Library/UefiBootServicesTableLib.h>
- #include <Library/RngLib.h>
- #include <Protocol/Rng.h>
- #include "RngDxeInternals.h"
- /** Free mAvailableAlgoArray.
- **/
- VOID
- EFIAPI
- FreeAvailableAlgorithms (
- VOID
- )
- {
- FreePool (mAvailableAlgoArray);
- return;
- }
- /**
- Produces and returns an RNG value using either the default or specified RNG algorithm.
- @param[in] This A pointer to the EFI_RNG_PROTOCOL instance.
- @param[in] RNGAlgorithm A pointer to the EFI_RNG_ALGORITHM that identifies the RNG
- algorithm to use. May be NULL in which case the function will
- use its default RNG algorithm.
- @param[in] RNGValueLength The length in bytes of the memory buffer pointed to by
- RNGValue. The driver shall return exactly this numbers of bytes.
- @param[out] RNGValue A caller-allocated memory buffer filled by the driver with the
- resulting RNG value.
- @retval EFI_SUCCESS The RNG value was returned successfully.
- @retval EFI_UNSUPPORTED The algorithm specified by RNGAlgorithm is not supported by
- this driver.
- @retval EFI_DEVICE_ERROR An RNG value could not be retrieved due to a hardware or
- firmware error.
- @retval EFI_NOT_READY There is not enough random data available to satisfy the length
- requested by RNGValueLength.
- @retval EFI_INVALID_PARAMETER RNGValue is NULL or RNGValueLength is zero.
- **/
- EFI_STATUS
- EFIAPI
- RngGetRNG (
- IN EFI_RNG_PROTOCOL *This,
- IN EFI_RNG_ALGORITHM *RNGAlgorithm OPTIONAL,
- IN UINTN RNGValueLength,
- OUT UINT8 *RNGValue
- )
- {
- EFI_STATUS Status;
- UINTN Index;
- if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) {
- return EFI_INVALID_PARAMETER;
- }
- if (RNGAlgorithm == NULL) {
- //
- // Use the default RNG algorithm if RNGAlgorithm is NULL.
- //
- for (Index = 0; Index < mAvailableAlgoArrayCount; Index++) {
- if (!IsZeroGuid (&mAvailableAlgoArray[Index])) {
- RNGAlgorithm = &mAvailableAlgoArray[Index];
- goto FoundAlgo;
- }
- }
- if (Index == mAvailableAlgoArrayCount) {
- // No algorithm available.
- ASSERT (Index != mAvailableAlgoArrayCount);
- return EFI_DEVICE_ERROR;
- }
- }
- FoundAlgo:
- if (CompareGuid (RNGAlgorithm, PcdGetPtr (PcdCpuRngSupportedAlgorithm))) {
- Status = RngGetBytes (RNGValueLength, RNGValue);
- return Status;
- }
- // Raw algorithm (Trng)
- if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {
- return GenerateEntropy (RNGValueLength, RNGValue);
- }
- //
- // Other algorithms are unsupported by this driver.
- //
- return EFI_UNSUPPORTED;
- }
- /**
- Returns information about the random number generation implementation.
- @param[in] This A pointer to the EFI_RNG_PROTOCOL instance.
- @param[in,out] RNGAlgorithmListSize On input, the size in bytes of RNGAlgorithmList.
- On output with a return code of EFI_SUCCESS, the size
- in bytes of the data returned in RNGAlgorithmList. On output
- with a return code of EFI_BUFFER_TOO_SMALL,
- the size of RNGAlgorithmList required to obtain the list.
- @param[out] RNGAlgorithmList A caller-allocated memory buffer filled by the driver
- with one EFI_RNG_ALGORITHM element for each supported
- RNG algorithm. The list must not change across multiple
- calls to the same driver. The first algorithm in the list
- is the default algorithm for the driver.
- @retval EFI_SUCCESS The RNG algorithm list was returned successfully.
- @retval EFI_UNSUPPORTED The services is not supported by this driver.
- @retval EFI_DEVICE_ERROR The list of algorithms could not be retrieved due to a
- hardware or firmware error.
- @retval EFI_INVALID_PARAMETER One or more of the parameters are incorrect.
- @retval EFI_BUFFER_TOO_SMALL The buffer RNGAlgorithmList is too small to hold the result.
- **/
- EFI_STATUS
- EFIAPI
- RngGetInfo (
- IN EFI_RNG_PROTOCOL *This,
- IN OUT UINTN *RNGAlgorithmListSize,
- OUT EFI_RNG_ALGORITHM *RNGAlgorithmList
- )
- {
- UINTN RequiredSize;
- if ((This == NULL) || (RNGAlgorithmListSize == NULL)) {
- return EFI_INVALID_PARAMETER;
- }
- RequiredSize = mAvailableAlgoArrayCount * sizeof (EFI_RNG_ALGORITHM);
- if (RequiredSize == 0) {
- // No supported algorithms found.
- return EFI_UNSUPPORTED;
- }
- if (*RNGAlgorithmListSize < RequiredSize) {
- *RNGAlgorithmListSize = RequiredSize;
- return EFI_BUFFER_TOO_SMALL;
- }
- if (RNGAlgorithmList == NULL) {
- return EFI_INVALID_PARAMETER;
- }
- // There is no gap in the array, so copy the block.
- CopyMem (RNGAlgorithmList, mAvailableAlgoArray, RequiredSize);
- *RNGAlgorithmListSize = RequiredSize;
- return EFI_SUCCESS;
- }
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