863fe9e191
Bugzilla: 3668 (https://bugzilla.tianocore.org/show_bug.cgi?id=3668) RawAlgorithm is used to provide access to entropy that is suitable for cryptographic applications. Therefore, add RawAlgorithm support that provides access to entropy using the ArmTrngLib. Also remove unused UefiBootServicesTableLib library inclusion and Status variable. Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> Acked-by: Jiewen Yao <jiewen.yao@intel.com>
72 lines
2.0 KiB
C
72 lines
2.0 KiB
C
/** @file
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RNG Driver to produce the UEFI Random Number Generator protocol.
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The driver implements the EFI_RNG_ALGORITHM_RAW using the FW-TRNG
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interface to provide entropy.
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Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Library/BaseLib.h>
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#include <Library/BaseMemoryLib.h>
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#include <Library/DebugLib.h>
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#include <Library/ArmTrngLib.h>
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#include <Protocol/Rng.h>
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#include "RngDxeInternals.h"
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/**
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Generate high-quality entropy source using a TRNG or through RDRAND.
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@param[in] Length Size of the buffer, in bytes, to fill with.
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@param[out] Entropy Pointer to the buffer to store the entropy data.
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@retval RETURN_SUCCESS The function completed successfully.
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@retval RETURN_INVALID_PARAMETER Invalid parameter.
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@retval RETURN_UNSUPPORTED Function not implemented.
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@retval RETURN_BAD_BUFFER_SIZE Buffer size is too small.
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@retval RETURN_NOT_READY No Entropy available.
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**/
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EFI_STATUS
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EFIAPI
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GenerateEntropy (
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IN UINTN Length,
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OUT UINT8 *Entropy
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)
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{
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EFI_STATUS Status;
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UINTN CollectedEntropyBits;
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UINTN RequiredEntropyBits;
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UINTN EntropyBits;
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UINTN Index;
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UINTN MaxBits;
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ZeroMem (Entropy, Length);
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RequiredEntropyBits = (Length << 3);
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Index = 0;
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CollectedEntropyBits = 0;
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MaxBits = GetArmTrngMaxSupportedEntropyBits ();
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while (CollectedEntropyBits < RequiredEntropyBits) {
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EntropyBits = MIN ((RequiredEntropyBits - CollectedEntropyBits), MaxBits);
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Status = GetArmTrngEntropy (
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EntropyBits,
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(Length - Index),
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&Entropy[Index]
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);
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if (EFI_ERROR (Status)) {
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// Discard the collected bits.
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ZeroMem (Entropy, Length);
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return Status;
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}
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CollectedEntropyBits += EntropyBits;
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Index += (EntropyBits >> 3);
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} // while
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return Status;
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}
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