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| author | Pierre Gondois <pierre.gondois@arm.com> | 2023-08-11 16:33:02 +0200 |
|---|---|---|
| committer | mergify[bot] <37929162+mergify[bot]@users.noreply.github.com> | 2023-09-08 09:48:55 +0000 |
| commit | 2f981bddcbd6adde5f682caf0d3812ba92bc0f73 (patch) | |
| tree | 3bb15ec0ec92d9fc30e76209c20cddea8573a71e /MdeModulePkg/Library | |
| parent | 2ce5ae43c2166984d20341993c4b9dbb337aad79 (diff) | |
| download | edk2-2f981bddcbd6adde5f682caf0d3812ba92bc0f73.tar.gz edk2-2f981bddcbd6adde5f682caf0d3812ba92bc0f73.tar.bz2 edk2-2f981bddcbd6adde5f682caf0d3812ba92bc0f73.zip | |
MdeModulePkg: Duplicate BaseRngLibTimerLib to MdeModulePkg
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4504
The BaseRngLibTimerLib allows to generate number based on a timer.
This mechanism allows to have a basic non-secure implementation
for non-production platforms.
To bind and identify Random Number Generators implementations with
a GUID, an unsafe GUID should be added. This GUID cannot be added
to the MdePkg unless it is also added to a specification.
To keep the MdePkg self-contained, copy the BaseRngLibTimerLib to
the MdeModulePkg. This will allow to define an unsafe Rng GUID
in a later patch in the MdeModulePkg.
The MdePkg implementation will be removed later. This allows to give
some time to platform owners to switch to the MdeModulePkg
implementation.
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Kun Qin <kun.qin@microsoft.com>
Diffstat (limited to 'MdeModulePkg/Library')
3 files changed, 243 insertions, 0 deletions
diff --git a/MdeModulePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf b/MdeModulePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf new file mode 100644 index 0000000000..f857290e82 --- /dev/null +++ b/MdeModulePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf @@ -0,0 +1,36 @@ +## @file
+# Instance of RNG (Random Number Generator) Library.
+#
+# BaseRng Library that uses the TimerLib to provide reasonably random numbers.
+# Do NOT use this on a production system as this uses the system performance
+# counter rather than a true source of random in addition to having a weak
+# random algorithm. This is provided primarily as a source of entropy for
+# OpenSSL for platforms that do not have a good built in RngLib as this
+# emulates what was done before (though it isn't perfect).
+#
+# Copyright (c) Microsoft Corporation. All rights reserved.<BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#
+##
+
+[Defines]
+ INF_VERSION = 1.27
+ BASE_NAME = BaseRngLibTimerLib
+ MODULE_UNI_FILE = BaseRngLibTimerLib.uni
+ FILE_GUID = 74950C45-10FC-4AB5-B114-49C87C17409B
+ MODULE_TYPE = BASE
+ VERSION_STRING = 1.0
+ LIBRARY_CLASS = RngLib
+
+[Sources]
+ RngLibTimer.c
+
+[Packages]
+ MdePkg/MdePkg.dec
+
+[LibraryClasses]
+ BaseLib
+ DebugLib
+ TimerLib
diff --git a/MdeModulePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.uni b/MdeModulePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.uni new file mode 100644 index 0000000000..fde24b9f01 --- /dev/null +++ b/MdeModulePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.uni @@ -0,0 +1,15 @@ +// @file
+// Instance of RNG (Random Number Generator) Library.
+//
+// RngLib that uses TimerLib's performance counter to provide random numbers.
+//
+// Copyright (c) Microsoft Corporation.
+//
+// SPDX-License-Identifier: BSD-2-Clause-Patent
+//
+
+
+#string STR_MODULE_ABSTRACT #language en-US "Instance of RNG Library"
+
+#string STR_MODULE_DESCRIPTION #language en-US "BaseRng Library that uses the TimerLib to provide low-entropy random numbers"
+
diff --git a/MdeModulePkg/Library/BaseRngLibTimerLib/RngLibTimer.c b/MdeModulePkg/Library/BaseRngLibTimerLib/RngLibTimer.c new file mode 100644 index 0000000000..980854d67b --- /dev/null +++ b/MdeModulePkg/Library/BaseRngLibTimerLib/RngLibTimer.c @@ -0,0 +1,192 @@ +/** @file
+ BaseRng Library that uses the TimerLib to provide reasonably random numbers.
+ Do not use this on a production system.
+
+ Copyright (c) Microsoft Corporation.
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Base.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/TimerLib.h>
+
+#define DEFAULT_DELAY_TIME_IN_MICROSECONDS 10
+
+/**
+ Using the TimerLib GetPerformanceCounterProperties() we delay
+ for enough time for the PerformanceCounter to increment.
+
+ If the return value from GetPerformanceCounterProperties (TimerLib)
+ is zero, this function will return 10 and attempt to assert.
+ **/
+STATIC
+UINT32
+CalculateMinimumDecentDelayInMicroseconds (
+ VOID
+ )
+{
+ UINT64 CounterHz;
+
+ // Get the counter properties
+ CounterHz = GetPerformanceCounterProperties (NULL, NULL);
+ // Make sure we won't divide by zero
+ if (CounterHz == 0) {
+ ASSERT (CounterHz != 0); // Assert so the developer knows something is wrong
+ return DEFAULT_DELAY_TIME_IN_MICROSECONDS;
+ }
+
+ // Calculate the minimum delay based on 1.5 microseconds divided by the hertz.
+ // We calculate the length of a cycle (1/CounterHz) and multiply it by 1.5 microseconds
+ // This ensures that the performance counter has increased by at least one
+ return (UINT32)(MAX (DivU64x64Remainder (1500000, CounterHz, NULL), 1));
+}
+
+/**
+ Generates a 16-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @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
+ )
+{
+ UINT32 Index;
+ UINT8 *RandPtr;
+ UINT32 DelayInMicroSeconds;
+
+ ASSERT (Rand != NULL);
+
+ if (Rand == NULL) {
+ return FALSE;
+ }
+
+ DelayInMicroSeconds = CalculateMinimumDecentDelayInMicroseconds ();
+ RandPtr = (UINT8 *)Rand;
+ // Get 2 bytes of random ish data
+ for (Index = 0; Index < sizeof (UINT16); Index++) {
+ *RandPtr = (UINT8)(GetPerformanceCounter () & 0xFF);
+ // Delay to give the performance counter a chance to change
+ MicroSecondDelay (DelayInMicroSeconds);
+ RandPtr++;
+ }
+
+ return TRUE;
+}
+
+/**
+ Generates a 32-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @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
+ )
+{
+ UINT32 Index;
+ UINT8 *RandPtr;
+ UINT32 DelayInMicroSeconds;
+
+ ASSERT (Rand != NULL);
+
+ if (NULL == Rand) {
+ return FALSE;
+ }
+
+ RandPtr = (UINT8 *)Rand;
+ DelayInMicroSeconds = CalculateMinimumDecentDelayInMicroseconds ();
+ // Get 4 bytes of random ish data
+ for (Index = 0; Index < sizeof (UINT32); Index++) {
+ *RandPtr = (UINT8)(GetPerformanceCounter () & 0xFF);
+ // Delay to give the performance counter a chance to change
+ MicroSecondDelay (DelayInMicroSeconds);
+ RandPtr++;
+ }
+
+ return TRUE;
+}
+
+/**
+ Generates a 64-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @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
+ )
+{
+ UINT32 Index;
+ UINT8 *RandPtr;
+ UINT32 DelayInMicroSeconds;
+
+ ASSERT (Rand != NULL);
+
+ if (NULL == Rand) {
+ return FALSE;
+ }
+
+ RandPtr = (UINT8 *)Rand;
+ DelayInMicroSeconds = CalculateMinimumDecentDelayInMicroseconds ();
+ // Get 8 bytes of random ish data
+ for (Index = 0; Index < sizeof (UINT64); Index++) {
+ *RandPtr = (UINT8)(GetPerformanceCounter () & 0xFF);
+ // Delay to give the performance counter a chance to change
+ MicroSecondDelay (DelayInMicroSeconds);
+ RandPtr++;
+ }
+
+ return TRUE;
+}
+
+/**
+ Generates a 128-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @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
+ )
+{
+ ASSERT (Rand != NULL);
+ // This should take around 80ms
+
+ // Read first 64 bits
+ if (!GetRandomNumber64 (Rand)) {
+ return FALSE;
+ }
+
+ // Read second 64 bits
+ return GetRandomNumber64 (++Rand);
+}
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