From f56ed0e51d39d74e53c3bc1f4bf40e91ed99cf1b Mon Sep 17 00:00:00 2001 From: Matthew Carlson Date: Mon, 27 Jul 2020 18:36:24 -0700 Subject: [PATCH] MdePkg: TimerRngLib: Added RngLib that uses TimerLib Added a new RngLib that provides random numbers from the TimerLib using the performance counter. This is meant to be used for OpenSSL to replicate past behavior. This should not be used in production as a real source of entropy. Ref: https://github.com/tianocore/edk2/pull/845 Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1871 Cc: Ard Biesheuvel Cc: Michael D Kinney Cc: Liming Gao Cc: Zhiguang Liu Reviewed-by: Liming Gao Signed-off-by: Matthew Carlson --- .../BaseRngLibTimerLib/BaseRngLibTimerLib.inf | 36 ++++ .../BaseRngLibTimerLib/BaseRngLibTimerLib.uni | 15 ++ .../Library/BaseRngLibTimerLib/RngLibTimer.c | 189 ++++++++++++++++++ MdePkg/MdePkg.dsc | 3 +- 4 files changed, 242 insertions(+), 1 deletion(-) create mode 100644 MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf create mode 100644 MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.uni create mode 100644 MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c diff --git a/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf b/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf new file mode 100644 index 0000000000..f857290e82 --- /dev/null +++ b/MdePkg/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.
+# +# 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/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.uni b/MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.uni new file mode 100644 index 0000000000..fde24b9f01 --- /dev/null +++ b/MdePkg/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/MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c b/MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c new file mode 100644 index 0000000000..54d29d96f3 --- /dev/null +++ b/MdePkg/Library/BaseRngLibTimerLib/RngLibTimer.c @@ -0,0 +1,189 @@ +/** @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 +#include +#include +#include + +#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); +} diff --git a/MdePkg/MdePkg.dsc b/MdePkg/MdePkg.dsc index 472fa37774..d7ba3a7309 100644 --- a/MdePkg/MdePkg.dsc +++ b/MdePkg/MdePkg.dsc @@ -62,6 +62,8 @@ MdePkg/Library/BasePostCodeLibPort80/BasePostCodeLibPort80.inf MdePkg/Library/BasePrintLib/BasePrintLib.inf MdePkg/Library/BaseReportStatusCodeLibNull/BaseReportStatusCodeLibNull.inf + MdePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf + MdePkg/Library/BaseRngLibNull/BaseRngLibNull.inf MdePkg/Library/BaseSerialPortLibNull/BaseSerialPortLibNull.inf MdePkg/Library/BaseSynchronizationLib/BaseSynchronizationLib.inf MdePkg/Library/BaseTimerLibNullTemplate/BaseTimerLibNullTemplate.inf @@ -69,7 +71,6 @@ MdePkg/Library/BaseUefiDecompressLib/BaseUefiTianoCustomDecompressLib.inf MdePkg/Library/BaseSmbusLibNull/BaseSmbusLibNull.inf MdePkg/Library/BaseSafeIntLib/BaseSafeIntLib.inf - MdePkg/Library/BaseRngLibNull/BaseRngLibNull.inf MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.inf MdePkg/Library/DxeCoreHobLib/DxeCoreHobLib.inf