/** @file | |
Provides an implementation of the library class RngLib that uses the Rng protocol. | |
Copyright (c) 2023, Arm Limited. All rights reserved. | |
Copyright (c) Microsoft Corporation. All rights reserved. | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
#include <Uefi.h> | |
#include <Library/UefiBootServicesTableLib.h> | |
#include <Library/DebugLib.h> | |
#include <Library/RngLib.h> | |
#include <Protocol/Rng.h> | |
/** | |
Routine Description: | |
Generates a random number via the NIST | |
800-9A algorithm. Refer to | |
http://csrc.nist.gov/groups/STM/cavp/documents/drbg/DRBGVS.pdf | |
for more information. | |
@param[out] Buffer Buffer to receive the random number. | |
@param[in] BufferSize Number of bytes in Buffer. | |
@retval EFI_SUCCESS or underlying failure code. | |
**/ | |
STATIC | |
EFI_STATUS | |
GenerateRandomNumberViaNist800Algorithm ( | |
OUT UINT8 *Buffer, | |
IN UINTN BufferSize | |
) | |
{ | |
EFI_STATUS Status; | |
EFI_RNG_PROTOCOL *RngProtocol; | |
RngProtocol = NULL; | |
if (Buffer == NULL) { | |
DEBUG ((DEBUG_ERROR, "%a: Buffer == NULL.\n", __func__)); | |
return EFI_INVALID_PARAMETER; | |
} | |
Status = gBS->LocateProtocol (&gEfiRngProtocolGuid, NULL, (VOID **)&RngProtocol); | |
if (EFI_ERROR (Status) || (RngProtocol == NULL)) { | |
DEBUG ((DEBUG_ERROR, "%a: Could not locate RNG prototocol, Status = %r\n", __func__, Status)); | |
return Status; | |
} | |
Status = RngProtocol->GetRNG (RngProtocol, &gEfiRngAlgorithmSp80090Ctr256Guid, BufferSize, Buffer); | |
DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm CTR-256 - Status = %r\n", __func__, Status)); | |
if (!EFI_ERROR (Status)) { | |
return Status; | |
} | |
Status = RngProtocol->GetRNG (RngProtocol, &gEfiRngAlgorithmSp80090Hmac256Guid, BufferSize, Buffer); | |
DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm HMAC-256 - Status = %r\n", __func__, Status)); | |
if (!EFI_ERROR (Status)) { | |
return Status; | |
} | |
Status = RngProtocol->GetRNG (RngProtocol, &gEfiRngAlgorithmSp80090Hash256Guid, BufferSize, Buffer); | |
DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm Hash-256 - Status = %r\n", __func__, Status)); | |
if (!EFI_ERROR (Status)) { | |
return Status; | |
} | |
Status = RngProtocol->GetRNG (RngProtocol, &gEfiRngAlgorithmRaw, BufferSize, Buffer); | |
DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm Raw - Status = %r\n", __func__, Status)); | |
if (!EFI_ERROR (Status)) { | |
return Status; | |
} | |
// If all the other methods have failed, use the default method from the RngProtocol | |
Status = RngProtocol->GetRNG (RngProtocol, NULL, BufferSize, Buffer); | |
DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm default - Status = %r\n", __func__, Status)); | |
if (!EFI_ERROR (Status)) { | |
return Status; | |
} | |
// If we get to this point, we have failed | |
DEBUG ((DEBUG_ERROR, "%a: GetRNG() failed, staus = %r\n", __func__, Status)); | |
return Status; | |
}// GenerateRandomNumberViaNist800Algorithm() | |
/** | |
Generates a 16-bit random number. | |
if Rand is NULL, return FALSE. | |
@param[out] Rand Buffer pointer to store the 16-bit random value. | |
@retval TRUE Random number generated successfully. | |
@retval FALSE Failed to generate the random number. | |
**/ | |
BOOLEAN | |
EFIAPI | |
GetRandomNumber16 ( | |
OUT UINT16 *Rand | |
) | |
{ | |
EFI_STATUS Status; | |
if (Rand == NULL) { | |
return FALSE; | |
} | |
Status = GenerateRandomNumberViaNist800Algorithm ((UINT8 *)Rand, sizeof (UINT16)); | |
if (EFI_ERROR (Status)) { | |
return FALSE; | |
} | |
return TRUE; | |
} | |
/** | |
Generates a 32-bit random number. | |
if Rand is NULL, return FALSE. | |
@param[out] Rand Buffer pointer to store the 32-bit random value. | |
@retval TRUE Random number generated successfully. | |
@retval FALSE Failed to generate the random number. | |
**/ | |
BOOLEAN | |
EFIAPI | |
GetRandomNumber32 ( | |
OUT UINT32 *Rand | |
) | |
{ | |
EFI_STATUS Status; | |
if (Rand == NULL) { | |
return FALSE; | |
} | |
Status = GenerateRandomNumberViaNist800Algorithm ((UINT8 *)Rand, sizeof (UINT32)); | |
if (EFI_ERROR (Status)) { | |
return FALSE; | |
} | |
return TRUE; | |
} | |
/** | |
Generates a 64-bit random number. | |
if Rand is NULL, return FALSE. | |
@param[out] Rand Buffer pointer to store the 64-bit random value. | |
@retval TRUE Random number generated successfully. | |
@retval FALSE Failed to generate the random number. | |
**/ | |
BOOLEAN | |
EFIAPI | |
GetRandomNumber64 ( | |
OUT UINT64 *Rand | |
) | |
{ | |
EFI_STATUS Status; | |
if (Rand == NULL) { | |
return FALSE; | |
} | |
Status = GenerateRandomNumberViaNist800Algorithm ((UINT8 *)Rand, sizeof (UINT64)); | |
if (EFI_ERROR (Status)) { | |
return FALSE; | |
} | |
return TRUE; | |
} | |
/** | |
Generates a 128-bit random number. | |
if Rand is NULL, return FALSE. | |
@param[out] Rand Buffer pointer to store the 128-bit random value. | |
@retval TRUE Random number generated successfully. | |
@retval FALSE Failed to generate the random number. | |
**/ | |
BOOLEAN | |
EFIAPI | |
GetRandomNumber128 ( | |
OUT UINT64 *Rand | |
) | |
{ | |
EFI_STATUS Status; | |
if (Rand == NULL) { | |
return FALSE; | |
} | |
Status = GenerateRandomNumberViaNist800Algorithm ((UINT8 *)Rand, 2 * sizeof (UINT64)); | |
if (EFI_ERROR (Status)) { | |
return FALSE; | |
} | |
return TRUE; | |
} | |
/** | |
Get a GUID identifying the RNG algorithm implementation. | |
@param [out] RngGuid If success, contains the GUID identifying | |
the RNG algorithm implementation. | |
@retval EFI_SUCCESS Success. | |
@retval EFI_UNSUPPORTED Not supported. | |
@retval EFI_INVALID_PARAMETER Invalid parameter. | |
**/ | |
EFI_STATUS | |
EFIAPI | |
GetRngGuid ( | |
GUID *RngGuid | |
) | |
{ | |
/* It is not possible to know beforehand which Rng algorithm will | |
* be used by this library. | |
* This API is mainly used by RngDxe. RngDxe relies on the RngLib. | |
* The RngLib|DxeRngLib.inf implementation locates and uses an installed | |
* EFI_RNG_PROTOCOL. | |
* It is thus not possible to have both RngDxe and RngLib|DxeRngLib.inf. | |
* and it is ok not to support this API. | |
*/ | |
return EFI_UNSUPPORTED; | |
} |