Hi Pierre,
Thank you for this patch.
Please find my response inline marked [SAMI].
With that addressed,
Reviewed-by: Sami Mujawar <sami.muja...@arm.com>
Regards,
Sami Mujawar
On 09/05/2023 08:40 am, pierre.gond...@arm.com wrote:
From: Pierre Gondois <pierre.gond...@arm.com>
The EFI_RNG_PROTOCOL can use the RngLib. The RngLib has multiple
implementations, some of them are unsafe (e.g. BaseRngLibTimerLib).
To allow the RngDxe to detect when such implementation is used,
add a GetRngGuid() function to the RngLib.
Signed-off-by: Pierre Gondois <pierre.gond...@arm.com>
---
MdePkg/Include/Library/RngLib.h | 17 ++++++++
MdePkg/Library/BaseRngLib/AArch64/Rndr.c | 42 +++++++++++++++++++
MdePkg/Library/BaseRngLib/BaseRngLib.inf | 9 ++++
MdePkg/Library/BaseRngLib/Rand/RdRand.c | 26 ++++++++++++
.../Library/BaseRngLibNull/BaseRngLibNull.c | 22 ++++++++++
.../BaseRngLibTimerLib/BaseRngLibTimerLib.inf | 3 ++
.../Library/BaseRngLibTimerLib/RngLibTimer.c | 28 +++++++++++++
MdePkg/Library/DxeRngLib/DxeRngLib.c | 28 +++++++++++++
8 files changed, 175 insertions(+)
diff --git a/MdePkg/Include/Library/RngLib.h b/MdePkg/Include/Library/RngLib.h
index 429ed19e287e..945482cd5e56 100644
--- a/MdePkg/Include/Library/RngLib.h
+++ b/MdePkg/Include/Library/RngLib.h
@@ -1,6 +1,7 @@
/** @file
Provides random number generator services.
+Copyright (c) 2023, Arm Limited. All rights reserved.<BR>
Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
@@ -77,4 +78,20 @@ GetRandomNumber128 (
OUT UINT64 *Rand
);
+/**
+ 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
+ );
+
#endif // __RNG_LIB_H__
diff --git a/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
index 20811bf3ebf3..d39db62153ee 100644
--- a/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
+++ b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
@@ -2,6 +2,7 @@
Random number generator service that uses the RNDR instruction
to provide pseudorandom numbers.
+ Copyright (c) 2023, Arm Limited. All rights reserved.<BR>
Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
@@ -11,6 +12,7 @@
#include <Uefi.h>
#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/RngLib.h>
@@ -138,3 +140,43 @@ ArchIsRngSupported (
{
return mRndrSupported;
}
+
+/**
+ 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
+ )
+{
+ GUID *RngLibGuid;
+
+ if (RngGuid == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ if (!mRndrSupported) {
+ return EFI_UNSUPPORTED;
+ }
+
+ //
+ // If the platform advertises the algorithm behind RNDR instruction,
+ // use it. Otherwise use gEfiRngAlgorithmArmRndr.
+ //
+ RngLibGuid = PcdGetPtr (PcdCpuRngSupportedAlgorithm);
+ if (!IsZeroGuid (RngLibGuid)) {
+ CopyMem (RngGuid, RngLibGuid, sizeof (*RngGuid));
+ } else {
+ CopyMem (RngGuid, &gEfiRngAlgorithmArmRndr, sizeof (*RngGuid));
+ }
+
+ return EFI_SUCCESS;
+}
diff --git a/MdePkg/Library/BaseRngLib/BaseRngLib.inf
b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
index 1fcceb941495..a79fbf03d74c 100644
--- a/MdePkg/Library/BaseRngLib/BaseRngLib.inf
+++ b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
@@ -4,6 +4,7 @@
# BaseRng Library that uses CPU RNG instructions (e.g. RdRand) to
# provide random numbers.
#
+# Copyright (c) 2023, Arm Limited. All rights reserved.<BR>
# Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
# Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
#
@@ -43,9 +44,17 @@ [Sources.AARCH64]
AArch64/ArmReadIdIsar0.asm | MSFT
AArch64/ArmRng.asm | MSFT
+[Guids]
+ gEfiRngAlgorithmArmRndr
+ gEfiRngAlgorithmSp80090Ctr256Guid
+ gEfiRngAlgorithmUnSafe
[SAMI] Maybe we can split the [Guids] section into [Guids.AARCH64] and
[Guids.Ia32, Guids.X64].
Also gEfiRngAlgorithmUnSafe does not appear to be used and can be removed.
[/SAMI]
+
[Packages]
MdePkg/MdePkg.dec
+[Pcd.AARCH64]
+ gEfiMdePkgTokenSpaceGuid.PcdCpuRngSupportedAlgorithm
+
[LibraryClasses]
BaseLib
DebugLib
diff --git a/MdePkg/Library/BaseRngLib/Rand/RdRand.c
b/MdePkg/Library/BaseRngLib/Rand/RdRand.c
index 070d41e2555f..9bd68352f9f7 100644
--- a/MdePkg/Library/BaseRngLib/Rand/RdRand.c
+++ b/MdePkg/Library/BaseRngLib/Rand/RdRand.c
@@ -2,6 +2,7 @@
Random number generator services that uses RdRand instruction access
to provide high-quality random numbers.
+Copyright (c) 2023, Arm Limited. All rights reserved.<BR>
Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
@@ -11,6 +12,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
#include <Uefi.h>
#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include "BaseRngLibInternals.h"
@@ -128,3 +130,27 @@ ArchIsRngSupported (
*/
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
+ )
+{
+ if (RngGuid == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ CopyMem (RngGuid, &gEfiRngAlgorithmSp80090Ctr256Guid, sizeof (*RngGuid));
+ return EFI_SUCCESS;
+}
diff --git a/MdePkg/Library/BaseRngLibNull/BaseRngLibNull.c
b/MdePkg/Library/BaseRngLibNull/BaseRngLibNull.c
index efba5c851ead..af5e8eb8f72a 100644
--- a/MdePkg/Library/BaseRngLibNull/BaseRngLibNull.c
+++ b/MdePkg/Library/BaseRngLibNull/BaseRngLibNull.c
@@ -1,13 +1,16 @@
/** @file
Null version of Random number generator services.
+Copyright (c) 2023, Arm Limited. All rights reserved.<BR>
Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
+#include <Uefi.h>
#include <Library/DebugLib.h>
#include <Library/RngLib.h>
+#include <Protocol/Rng.h>
/**
Generates a 16-bit random number.
@@ -92,3 +95,22 @@ GetRandomNumber128 (
ASSERT (FALSE);
return FALSE;
}
+
+/**
+ 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
+ )
+{
+ return EFI_UNSUPPORTED;
+}
diff --git a/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf
b/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf
index f857290e823b..13e10141fad0 100644
--- a/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf
+++ b/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf
@@ -30,6 +30,9 @@ [Sources]
[Packages]
MdePkg/MdePkg.dec
+[Guids]
+ gEfiRngAlgorithmUnSafe
+
[LibraryClasses]
BaseLib
DebugLib
diff --git a/MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c
b/MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c
index 980854d67b72..fc9f7e31a333 100644
--- a/MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c
+++ b/MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c
@@ -2,14 +2,18 @@
BaseRng Library that uses the TimerLib to provide reasonably random numbers.
Do not use this on a production system.
+ Copyright (c) 2023, Arm Limited. All rights reserved.
Copyright (c) Microsoft Corporation.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Base.h>
+#include <Uefi.h>
#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/TimerLib.h>
+#include <Protocol/Rng.h>
#define DEFAULT_DELAY_TIME_IN_MICROSECONDS 10
@@ -190,3 +194,27 @@ GetRandomNumber128 (
// Read second 64 bits
return GetRandomNumber64 (++Rand);
}
+
+/**
+ 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
+ )
+{
+ if (RngGuid == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ CopyMem (RngGuid, &gEfiRngAlgorithmUnSafe, sizeof (*RngGuid));
+ return EFI_SUCCESS;
+}
diff --git a/MdePkg/Library/DxeRngLib/DxeRngLib.c
b/MdePkg/Library/DxeRngLib/DxeRngLib.c
index a01b66ad7d20..cd23859e3112 100644
--- a/MdePkg/Library/DxeRngLib/DxeRngLib.c
+++ b/MdePkg/Library/DxeRngLib/DxeRngLib.c
@@ -1,6 +1,7 @@
/** @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
@@ -207,3 +208,30 @@ GetRandomNumber128 (
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;
+}
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