/** @file | |
RNG Driver to produce the UEFI Random Number Generator protocol. | |
The driver will use the new RDRAND instruction to produce high-quality, high-performance | |
entropy and random number. | |
RNG Algorithms defined in UEFI 2.4: | |
- EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID - Supported | |
(RDRAND implements a hardware NIST SP800-90 AES-CTR-256 based DRBG) | |
- EFI_RNG_ALGORITHM_RAW - Supported | |
(Structuring RDRAND invocation can be guaranteed as high-quality entropy source) | |
- EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID - Unsupported | |
- EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID - Unsupported | |
- EFI_RNG_ALGORITHM_X9_31_3DES_GUID - Unsupported | |
- EFI_RNG_ALGORITHM_X9_31_AES_GUID - Unsupported | |
Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR> | |
Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR> | |
(C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR> | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
#include <Library/BaseLib.h> | |
#include <Library/BaseMemoryLib.h> | |
#include "RngDxeInternals.h" | |
// | |
// Count of Rng algorithms. | |
// | |
#define RNG_ALGORITHM_COUNT 2 | |
/** Allocate and initialize mAvailableAlgoArray with the available | |
Rng algorithms. Also update mAvailableAlgoArrayCount. | |
@retval EFI_SUCCESS The function completed successfully. | |
@retval EFI_OUT_OF_RESOURCES Could not allocate memory. | |
**/ | |
EFI_STATUS | |
EFIAPI | |
GetAvailableAlgorithms ( | |
VOID | |
) | |
{ | |
mAvailableAlgoArrayCount = RNG_ALGORITHM_COUNT; | |
return EFI_SUCCESS; | |
} | |
/** Free mAvailableAlgoArray. | |
**/ | |
VOID | |
EFIAPI | |
FreeAvailableAlgorithms ( | |
VOID | |
) | |
{ | |
mAvailableAlgoArrayCount = 0; | |
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; | |
if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) { | |
return EFI_INVALID_PARAMETER; | |
} | |
Status = EFI_UNSUPPORTED; | |
if (RNGAlgorithm == NULL) { | |
// | |
// Use the default RNG algorithm if RNGAlgorithm is NULL. | |
// | |
RNGAlgorithm = &gEfiRngAlgorithmSp80090Ctr256Guid; | |
} | |
// | |
// NIST SP800-90-AES-CTR-256 supported by RDRAND | |
// | |
if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmSp80090Ctr256Guid)) { | |
Status = RngGetBytes (RNGValueLength, RNGValue); | |
return Status; | |
} | |
// | |
// The "raw" algorithm is intended to provide entropy directly | |
// | |
if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) { | |
// | |
// When a DRBG is used on the output of a entropy source, | |
// its security level must be at least 256 bits according to UEFI Spec. | |
// | |
if (RNGValueLength < 32) { | |
return EFI_INVALID_PARAMETER; | |
} | |
Status = GenerateEntropy (RNGValueLength, RNGValue); | |
return Status; | |
} | |
// | |
// Other algorithms were unsupported by this driver. | |
// | |
return Status; | |
} | |
/** | |
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 No supported algorithms found. | |
@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 = RNG_ALGORITHM_COUNT * sizeof (EFI_RNG_ALGORITHM); | |
if (*RNGAlgorithmListSize < RequiredSize) { | |
*RNGAlgorithmListSize = RequiredSize; | |
return EFI_BUFFER_TOO_SMALL; | |
} | |
if (RNGAlgorithmList == NULL) { | |
return EFI_INVALID_PARAMETER; | |
} | |
CopyMem (&RNGAlgorithmList[0], &gEfiRngAlgorithmSp80090Ctr256Guid, sizeof (EFI_RNG_ALGORITHM)); | |
// x86 platforms also support EFI_RNG_ALGORITHM_RAW via RDSEED | |
CopyMem (&RNGAlgorithmList[1], &gEfiRngAlgorithmRaw, sizeof (EFI_RNG_ALGORITHM)); | |
*RNGAlgorithmListSize = RequiredSize; | |
return EFI_SUCCESS; | |
} |