From 641da27ad73e8f09c40e8b093dcf824c0ee4d02a Mon Sep 17 00:00:00 2001 From: CoprDistGit Date: Thu, 1 Aug 2024 14:44:22 +0000 Subject: automatic import of edk2 --- ...RngLib-Add-a-smoketest-for-RDRAND-and-che.patch | 192 +++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 0036-MdePkg-BaseRngLib-Add-a-smoketest-for-RDRAND-and-che.patch (limited to '0036-MdePkg-BaseRngLib-Add-a-smoketest-for-RDRAND-and-che.patch') diff --git a/0036-MdePkg-BaseRngLib-Add-a-smoketest-for-RDRAND-and-che.patch b/0036-MdePkg-BaseRngLib-Add-a-smoketest-for-RDRAND-and-che.patch new file mode 100644 index 0000000..653b277 --- /dev/null +++ b/0036-MdePkg-BaseRngLib-Add-a-smoketest-for-RDRAND-and-che.patch @@ -0,0 +1,192 @@ +From 3899f089b8197f52ca63fe1561f8e5e1341f8198 Mon Sep 17 00:00:00 2001 +From: Pedro Falcato +Date: Tue, 22 Nov 2022 22:31:03 +0000 +Subject: [PATCH] MdePkg/BaseRngLib: Add a smoketest for RDRAND and check CPUID + +RDRAND has notoriously been broken many times over its lifespan. +Add a smoketest to RDRAND, in order to better sniff out potential +security concerns. + +Also add a proper CPUID test in order to support older CPUs which may +not have it; it was previously being tested but then promptly ignored. + +Testing algorithm inspired by linux's arch/x86/kernel/cpu/rdrand.c +:x86_init_rdrand() per commit 049f9ae9.. + +Many thanks to Jason Donenfeld for relicensing his linux RDRAND detection +code to MIT and the public domain. + +>On Tue, Nov 22, 2022 at 2:21 PM Jason A. Donenfeld wrote: + <..> +> I (re)wrote that function in Linux. I hereby relicense it as MIT, and +> also place it into public domain. Do with it what you will now. +> +> Jason + +BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4163 + +Signed-off-by: Pedro Falcato +Cc: Michael D Kinney +Cc: Liming Gao +Cc: Zhiguang Liu +Cc: Jason A. Donenfeld +(cherry picked from commit c3a8ca7b54a9fd17acdf16c6282a92cc989fa92a) +--- + MdePkg/Library/BaseRngLib/Rand/RdRand.c | 99 +++++++++++++++++++++++-- + 1 file changed, 91 insertions(+), 8 deletions(-) + +diff --git a/MdePkg/Library/BaseRngLib/Rand/RdRand.c b/MdePkg/Library/BaseRngLib/Rand/RdRand.c +index 9bd68352f9..06d2a6f12d 100644 +--- a/MdePkg/Library/BaseRngLib/Rand/RdRand.c ++++ b/MdePkg/Library/BaseRngLib/Rand/RdRand.c +@@ -3,6 +3,7 @@ + to provide high-quality random numbers. + + Copyright (c) 2023, Arm Limited. All rights reserved.
++Copyright (c) 2022, Pedro Falcato. All rights reserved.
+ Copyright (c) 2021, NUVIA Inc. All rights reserved.
+ Copyright (c) 2015, Intel Corporation. All rights reserved.
+ +@@ -24,6 +25,88 @@ SPDX-License-Identifier: BSD-2-Clause-Patent + + STATIC BOOLEAN mRdRandSupported; + ++// ++// Intel SDM says 10 tries is good enough for reliable RDRAND usage. ++// ++#define RDRAND_RETRIES 10 ++ ++#define RDRAND_TEST_SAMPLES 8 ++ ++#define RDRAND_MIN_CHANGE 5 ++ ++// ++// Add a define for native-word RDRAND, just for the test. ++// ++#ifdef MDE_CPU_X64 ++#define ASM_RDRAND AsmRdRand64 ++#else ++#define ASM_RDRAND AsmRdRand32 ++#endif ++ ++/** ++ Tests RDRAND for broken implementations. ++ ++ @retval TRUE RDRAND is reliable (and hopefully safe). ++ @retval FALSE RDRAND is unreliable and should be disabled, despite CPUID. ++ ++**/ ++STATIC ++BOOLEAN ++TestRdRand ( ++ VOID ++ ) ++{ ++ // ++ // Test for notoriously broken rdrand implementations that always return the same ++ // value, like the Zen 3 uarch (all-1s) or other several AMD families on suspend/resume (also all-1s). ++ // Note that this should be expanded to extensively test for other sorts of possible errata. ++ // ++ ++ // ++ // Our algorithm samples rdrand $RDRAND_TEST_SAMPLES times and expects ++ // a different result $RDRAND_MIN_CHANGE times for reliable RDRAND usage. ++ // ++ UINTN Prev; ++ UINT8 Idx; ++ UINT8 TestIteration; ++ UINT32 Changed; ++ ++ Changed = 0; ++ ++ for (TestIteration = 0; TestIteration < RDRAND_TEST_SAMPLES; TestIteration++) { ++ UINTN Sample; ++ // ++ // Note: We use a retry loop for rdrand. Normal users get this in BaseRng.c ++ // Any failure to get a random number will assume RDRAND does not work. ++ // ++ for (Idx = 0; Idx < RDRAND_RETRIES; Idx++) { ++ if (ASM_RDRAND (&Sample)) { ++ break; ++ } ++ } ++ ++ if (Idx == RDRAND_RETRIES) { ++ DEBUG ((DEBUG_ERROR, "BaseRngLib/x86: CPU BUG: Failed to get an RDRAND random number - disabling\n")); ++ return FALSE; ++ } ++ ++ if (TestIteration != 0) { ++ Changed += Sample != Prev; ++ } ++ ++ Prev = Sample; ++ } ++ ++ if (Changed < RDRAND_MIN_CHANGE) { ++ DEBUG ((DEBUG_ERROR, "BaseRngLib/x86: CPU BUG: RDRAND not reliable - disabling\n")); ++ return FALSE; ++ } ++ ++ return TRUE; ++} ++ ++#undef ASM_RDRAND ++ + /** + The constructor function checks whether or not RDRAND instruction is supported + by the host hardware. +@@ -48,10 +131,13 @@ BaseRngLibConstructor ( + // CPUID. A value of 1 indicates that processor support RDRAND instruction. + // + AsmCpuid (1, 0, 0, &RegEcx, 0); +- ASSERT ((RegEcx & RDRAND_MASK) == RDRAND_MASK); + + mRdRandSupported = ((RegEcx & RDRAND_MASK) == RDRAND_MASK); + ++ if (mRdRandSupported) { ++ mRdRandSupported = TestRdRand (); ++ } ++ + return EFI_SUCCESS; + } + +@@ -70,6 +156,7 @@ ArchGetRandomNumber16 ( + OUT UINT16 *Rand + ) + { ++ ASSERT (mRdRandSupported); + return AsmRdRand16 (Rand); + } + +@@ -88,6 +175,7 @@ ArchGetRandomNumber32 ( + OUT UINT32 *Rand + ) + { ++ ASSERT (mRdRandSupported); + return AsmRdRand32 (Rand); + } + +@@ -106,6 +194,7 @@ ArchGetRandomNumber64 ( + OUT UINT64 *Rand + ) + { ++ ASSERT (mRdRandSupported); + return AsmRdRand64 (Rand); + } + +@@ -122,13 +211,7 @@ ArchIsRngSupported ( + VOID + ) + { +- /* +- Existing software depends on this always returning TRUE, so for +- now hard-code it. +- +- return mRdRandSupported; +- */ +- return TRUE; ++ return mRdRandSupported; + } + + /** -- cgit v1.2.3