mirror of https://github.com/acidanthera/audk.git
ArmPkg/ArmTrngLib: Add Arm TRNG library
Bugzilla: 3668 (https://bugzilla.tianocore.org/show_bug.cgi?id=3668) The Arm True Random Number Generator Firmware, Interface 1.0, Platform Design Document (https://developer.arm.com/documentation/den0098/latest/) defines an interface between an Operating System (OS) executing at EL1 and Firmware (FW) exposing a conditioned entropy source that is provided by a TRNG back end. The conditioned entropy, that is provided by the Arm TRNG interface, is commonly used to seed deterministic random number generators. This patch adds an ArmTrngLib library that implements the Arm TRNG interface. Acked-by: Leif Lindholm <quic_llindhol@quicinc.com> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
This commit is contained in:
Sami Mujawar
mergify[bot]
parent
351fe77666
commit
e00ec499c5
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@ -131,6 +131,7 @@
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ArmPkg/Library/ArmGenericTimerPhyCounterLib/ArmGenericTimerPhyCounterLib.inf
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ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.inf
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ArmPkg/Library/ArmTrngLib/ArmTrngLib.inf
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ArmPkg/Library/ArmHvcLib/ArmHvcLib.inf
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ArmPkg/Library/ArmHvcLibNull/ArmHvcLibNull.inf
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ArmPkg/Library/ArmMonitorLib/ArmMonitorLib.inf
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/** @file
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Arm Firmware TRNG definitions.
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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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@par Reference(s):
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- [1] Arm True Random Number Generator Firmware, Interface 1.0,
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Platform Design Document.
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(https://developer.arm.com/documentation/den0098/latest/)
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@par Glossary:
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- TRNG - True Random Number Generator
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- FID - Function ID
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**/
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#ifndef ARM_FW_TRNG_DEFS_H_
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#define ARM_FW_TRNG_DEFS_H_
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#include <IndustryStandard/ArmStdSmc.h>
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// Firmware TRNG revision mask and shift
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#define TRNG_REV_MAJOR_MASK 0x7FFF
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#define TRNG_REV_MINOR_MASK 0xFFFF
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#define TRNG_REV_MAJOR_SHIFT 16
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#if defined (MDE_CPU_ARM)
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/** FID to use on AArch32 platform to request entropy.
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*/
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#define ARM_SMC_ID_TRNG_RND ARM_SMC_ID_TRNG_RND_AARCH32
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/** Maximum bits of entropy supported on AArch32.
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*/
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#define MAX_ENTROPY_BITS 96
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#elif defined (MDE_CPU_AARCH64)
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/** FID to use on AArch64 platform to request entropy.
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*/
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#define ARM_SMC_ID_TRNG_RND ARM_SMC_ID_TRNG_RND_AARCH64
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/** Maximum bits of entropy supported on AArch64.
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*/
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#define MAX_ENTROPY_BITS 192
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#else
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#error "Firmware TRNG not supported. Unknown chipset."
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#endif
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#endif // ARM_FW_TRNG_DEFS_H_
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@ -0,0 +1,388 @@
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/** @file
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Arm Firmware TRNG interface library.
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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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@par Reference(s):
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- [1] Arm True Random Number Generator Firmware, Interface 1.0,
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Platform Design Document.
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(https://developer.arm.com/documentation/den0098/latest/)
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- [2] NIST Special Publication 800-90B, Recommendation for the Entropy
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Sources Used for Random Bit Generation.
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(https://csrc.nist.gov/publications/detail/sp/800-90b/final)
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@par Glossary:
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- TRNG - True Random Number Generator
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- FID - Function ID
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**/
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#include <Base.h>
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#include <Library/ArmLib.h>
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#include <Library/ArmMonitorLib.h>
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#include <Library/BaseMemoryLib.h>
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#include <Library/DebugLib.h>
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#include "ArmTrngDefs.h"
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/** Convert TRNG status codes to RETURN status codes.
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@param [in] TrngStatus TRNG status code.
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@retval RETURN_SUCCESS Success.
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@retval RETURN_UNSUPPORTED Function not implemented or
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negative return code.
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@retval RETURN_INVALID_PARAMETER A parameter is invalid.
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@retval RETURN_NOT_READY No Entropy available.
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**/
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STATIC
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RETURN_STATUS
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TrngStatusToReturnStatus (
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IN INT32 TrngStatus
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)
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{
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switch (TrngStatus) {
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case TRNG_STATUS_NOT_SUPPORTED:
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return RETURN_UNSUPPORTED;
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case TRNG_STATUS_INVALID_PARAMETER:
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return RETURN_INVALID_PARAMETER;
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case TRNG_STATUS_NO_ENTROPY:
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return RETURN_NOT_READY;
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case TRNG_STATUS_SUCCESS:
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return RETURN_SUCCESS;
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default:
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if (TrngStatus < 0) {
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return RETURN_UNSUPPORTED;
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}
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return RETURN_SUCCESS;
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}
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}
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/** Get the version of the Arm TRNG backend.
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A TRNG may be implemented by the system firmware, in which case this
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function shall return the version of the Arm TRNG backend.
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The implementation must return NOT_SUPPORTED if a Back end is not present.
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@param [out] MajorRevision Major revision.
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@param [out] MinorRevision Minor revision.
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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 Backend not present.
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**/
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RETURN_STATUS
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EFIAPI
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GetArmTrngVersion (
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OUT UINT16 *MajorRevision,
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OUT UINT16 *MinorRevision
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)
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{
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RETURN_STATUS Status;
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ARM_MONITOR_ARGS Parameters;
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INT32 Revision;
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if ((MajorRevision == NULL) || (MinorRevision == NULL)) {
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return RETURN_INVALID_PARAMETER;
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}
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ZeroMem (&Parameters, sizeof (Parameters));
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Parameters.Arg0 = ARM_SMC_ID_TRNG_VERSION;
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ArmMonitorCall (&Parameters);
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Revision = (INT32)Parameters.Arg0;
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Status = TrngStatusToReturnStatus (Revision);
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if (RETURN_ERROR (Status)) {
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return Status;
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}
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*MinorRevision = (Revision & TRNG_REV_MINOR_MASK);
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*MajorRevision = ((Revision >> TRNG_REV_MAJOR_SHIFT) & TRNG_REV_MAJOR_MASK);
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return RETURN_SUCCESS;
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}
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/** Get the features supported by the Arm TRNG backend.
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The caller can determine if functions defined in the Arm TRNG ABI are
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present in the ABI implementation.
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@param [in] FunctionId Function Id.
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@param [out] Capability Function specific capability if present.
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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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**/
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STATIC
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RETURN_STATUS
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EFIAPI
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GetArmTrngFeatures (
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IN CONST UINT32 FunctionId,
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OUT UINT32 *Capability OPTIONAL
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)
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{
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ARM_MONITOR_ARGS Parameters;
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RETURN_STATUS Status;
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ZeroMem (&Parameters, sizeof (Parameters));
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Parameters.Arg0 = ARM_SMC_ID_TRNG_FEATURES;
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Parameters.Arg1 = FunctionId;
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ArmMonitorCall (&Parameters);
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Status = TrngStatusToReturnStatus (Parameters.Arg0);
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if (RETURN_ERROR (Status)) {
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return Status;
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}
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if (Capability != NULL) {
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*Capability = (UINT32)Parameters.Arg0;
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}
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return RETURN_SUCCESS;
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}
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/** Get the UUID of the Arm TRNG backend.
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A TRNG may be implemented by the system firmware, in which case this
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function shall return the UUID of the TRNG backend.
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Returning the Arm TRNG UUID is optional and if not implemented,
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RETURN_UNSUPPORTED shall be returned.
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Note: The caller must not rely on the returned UUID as a trustworthy Arm TRNG
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Back end identity
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@param [out] Guid UUID of the Arm TRNG backend.
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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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**/
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RETURN_STATUS
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EFIAPI
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GetArmTrngUuid (
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OUT GUID *Guid
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)
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{
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ARM_MONITOR_ARGS Parameters;
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if (Guid == NULL) {
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return RETURN_INVALID_PARAMETER;
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}
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ZeroMem (&Parameters, sizeof (Parameters));
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Parameters.Arg0 = ARM_SMC_ID_TRNG_GET_UUID;
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ArmMonitorCall (&Parameters);
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// Only invalid value is TRNG_STATUS_NOT_SUPPORTED (-1).
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if ((INT32)Parameters.Arg0 == TRNG_STATUS_NOT_SUPPORTED) {
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return TrngStatusToReturnStatus ((INT32)Parameters.Arg0);
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}
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Guid->Data1 = (Parameters.Arg0 & MAX_UINT32);
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Guid->Data2 = (Parameters.Arg1 & MAX_UINT16);
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Guid->Data3 = ((Parameters.Arg1 >> 16) & MAX_UINT16);
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Guid->Data4[0] = (Parameters.Arg2 & MAX_UINT8);
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Guid->Data4[1] = ((Parameters.Arg2 >> 8) & MAX_UINT8);
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Guid->Data4[2] = ((Parameters.Arg2 >> 16) & MAX_UINT8);
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Guid->Data4[3] = ((Parameters.Arg2 >> 24) & MAX_UINT8);
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Guid->Data4[4] = (Parameters.Arg3 & MAX_UINT8);
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Guid->Data4[5] = ((Parameters.Arg3 >> 8) & MAX_UINT8);
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Guid->Data4[6] = ((Parameters.Arg3 >> 16) & MAX_UINT8);
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Guid->Data4[7] = ((Parameters.Arg3 >> 24) & MAX_UINT8);
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DEBUG ((DEBUG_INFO, "FW-TRNG: UUID %g\n", Guid));
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return RETURN_SUCCESS;
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}
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/** Returns maximum number of entropy bits that can be returned in a single
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call.
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@return Returns the maximum number of Entropy bits that can be returned
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in a single call to GetArmTrngEntropy().
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**/
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UINTN
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EFIAPI
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GetArmTrngMaxSupportedEntropyBits (
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VOID
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)
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{
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return MAX_ENTROPY_BITS;
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}
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/** Returns N bits of conditioned entropy.
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See [2] Section 2.3.1 GetEntropy: An Interface to the Entropy Source
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GetEntropy
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Input:
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bits_of_entropy: the requested amount of entropy
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Output:
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entropy_bitstring: The string that provides the requested entropy.
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status: A Boolean value that is TRUE if the request has been satisfied,
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and is FALSE otherwise.
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@param [in] EntropyBits Number of entropy bits requested.
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@param [in] BufferSize Size of the Buffer in bytes.
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@param [out] Buffer Buffer to return the entropy bits.
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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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RETURN_STATUS
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EFIAPI
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GetArmTrngEntropy (
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IN UINTN EntropyBits,
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IN UINTN BufferSize,
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OUT UINT8 *Buffer
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)
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{
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RETURN_STATUS Status;
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ARM_MONITOR_ARGS Parameters;
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UINTN EntropyBytes;
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UINTN LastValidBits;
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UINTN BytesToClear;
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UINTN EntropyData[3];
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if ((EntropyBits == 0) ||
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(EntropyBits > MAX_ENTROPY_BITS) ||
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(Buffer == NULL))
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{
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return RETURN_INVALID_PARAMETER;
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}
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EntropyBytes = (EntropyBits + 7) >> 3;
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if (EntropyBytes > BufferSize) {
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return RETURN_BAD_BUFFER_SIZE;
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}
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ZeroMem (Buffer, BufferSize);
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ZeroMem (&Parameters, sizeof (Parameters));
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Parameters.Arg0 = ARM_SMC_ID_TRNG_RND;
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Parameters.Arg1 = EntropyBits;
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ArmMonitorCall (&Parameters);
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Status = TrngStatusToReturnStatus ((INT32)Parameters.Arg0);
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if (RETURN_ERROR (Status)) {
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return Status;
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}
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// The entropy data is returned in the Parameters.Arg<3..1>
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// With the lower order bytes in Parameters.Arg3 and the higher
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// order bytes being stored in Parameters.Arg1.
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EntropyData[0] = Parameters.Arg3;
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EntropyData[1] = Parameters.Arg2;
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EntropyData[2] = Parameters.Arg1;
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CopyMem (Buffer, EntropyData, EntropyBytes);
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// Mask off any unused top bytes, in accordance with specification.
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BytesToClear = BufferSize - EntropyBytes;
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if (BytesToClear != 0) {
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ZeroMem (&Buffer[EntropyBytes], BytesToClear);
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}
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// Clear the unused MSB bits of the last byte.
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LastValidBits = EntropyBits & 0x7;
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if (LastValidBits != 0) {
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Buffer[EntropyBytes - 1] &= (0xFF >> (8 - LastValidBits));
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}
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return Status;
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}
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/** The constructor checks that the FW-TRNG interface is supported
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by the host firmware.
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It will ASSERT() if FW-TRNG is not supported.
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It will always return RETURN_SUCCESS.
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@retval RETURN_SUCCESS The constructor always returns RETURN_SUCCESS.
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**/
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RETURN_STATUS
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EFIAPI
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ArmTrngLibConstructor (
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VOID
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)
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{
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ARM_MONITOR_ARGS Parameters;
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RETURN_STATUS Status;
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UINT16 MajorRev;
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UINT16 MinorRev;
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GUID Guid;
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ZeroMem (&Parameters, sizeof (Parameters));
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Parameters.Arg0 = SMCCC_VERSION;
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ArmMonitorCall (&Parameters);
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Status = TrngStatusToReturnStatus ((INT32)Parameters.Arg0);
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if (RETURN_ERROR (Status)) {
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ASSERT_RETURN_ERROR (Status);
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goto ErrorHandler;
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}
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// Cf [1] s2.1.3 'Caller responsibilities',
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// SMCCC version must be greater or equal than 1.1
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if ((INT32)Parameters.Arg0 < 0x10001) {
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ASSERT_RETURN_ERROR (RETURN_UNSUPPORTED);
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goto ErrorHandler;
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}
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Status = GetArmTrngVersion (&MajorRev, &MinorRev);
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if (RETURN_ERROR (Status)) {
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ASSERT_RETURN_ERROR (Status);
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goto ErrorHandler;
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}
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// Check that the required features are present.
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Status = GetArmTrngFeatures (ARM_SMC_ID_TRNG_RND, NULL);
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if (RETURN_ERROR (Status)) {
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ASSERT_RETURN_ERROR (Status);
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goto ErrorHandler;
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}
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// Check if TRNG UUID is supported and if so trace the GUID.
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Status = GetArmTrngFeatures (ARM_SMC_ID_TRNG_GET_UUID, NULL);
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if (RETURN_ERROR (Status)) {
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ASSERT_RETURN_ERROR (Status);
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goto ErrorHandler;
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}
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DEBUG_CODE_BEGIN ();
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Status = GetArmTrngUuid (&Guid);
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if (RETURN_ERROR (Status)) {
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ASSERT_RETURN_ERROR (Status);
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goto ErrorHandler;
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}
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DEBUG ((
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DEBUG_INFO,
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"FW-TRNG: Version %d.%d, GUID {%g}\n",
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MajorRev,
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MinorRev,
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Guid
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));
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DEBUG_CODE_END ();
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return RETURN_SUCCESS;
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ErrorHandler:
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DEBUG ((DEBUG_ERROR, "ArmTrngLib could not be correctly initialized.\n"));
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return RETURN_SUCCESS;
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}
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@ -0,0 +1,29 @@
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## @file
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# Arm Firmware TRNG interface library.
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#
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# Copyright (c) 2021 - 2022, Arm Limited. All rights reserved.<BR>
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#
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# SPDX-License-Identifier: BSD-2-Clause-Patent
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##
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[Defines]
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INF_VERSION = 1.29
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BASE_NAME = ArmTrngLib
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FILE_GUID = 10DE97C9-28E4-4C9B-A53E-8D7D1B0DD4E0
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VERSION_STRING = 1.0
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MODULE_TYPE = BASE
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LIBRARY_CLASS = ArmTrngLib
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CONSTRUCTOR = ArmTrngLibConstructor
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[Sources]
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ArmTrngDefs.h
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ArmTrngLib.c
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[Packages]
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ArmPkg/ArmPkg.dec
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MdePkg/MdePkg.dec
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[LibraryClasses]
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ArmMonitorLib
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BaseLib
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BaseMemoryLib
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