<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> <div class="moz-cite-prefix">On 8/12/21 9:48 AM, Marc-André Lureau wrote: </div> <blockquote type="cite" cite="mid:CAMxuvayQeBK1GXSMjF3ErnxTwk05o7YRO0y2Fo2g1JUxG2tZcw@mail.gmail.com"> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <div dir="ltr"> <div dir="ltr">Hi </div> <div class="gmail_quote"> <div dir="ltr" class="gmail_attr">On Tue, Aug 10, 2021 at 9:22 PM Stefan Berger <<a href="mailto:stefanb@linux.vnet.ibm.com" moz-do-not-send="true">stefanb@linux.vnet.ibm.com</a>> wrote: </div> <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Import PeiDxeTpmPlatformHierarchyLib.c from edk2-platforms. Modify it so that ConfigureTpmPlatformHierarchy() is the only public function provided by this file. Signed-off-by: Stefan Berger <<a href="mailto:stefanb@linux.ibm.com" target="_blank" moz-do-not-send="true">stefanb@linux.ibm.com</a>> --- .../Include/Library/TpmPlatformHierarchyLib.h | 27 +++ .../PeiDxeTpmPlatformHierarchyLib.c | 210 ++++++++++++++++++ .../PeiDxeTpmPlatformHierarchyLib.inf | 40 ++++ 3 files changed, 277 insertions(+) create mode 100644 OvmfPkg/Include/Library/TpmPlatformHierarchyLib.h create mode 100644 OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.c create mode 100644 OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.inf diff --git a/OvmfPkg/Include/Library/TpmPlatformHierarchyLib.h b/OvmfPkg/Include/Library/TpmPlatformHierarchyLib.h new file mode 100644 index 0000000000..a872fa09dc --- /dev/null +++ b/OvmfPkg/Include/Library/TpmPlatformHierarchyLib.h @@ -0,0 +1,27 @@ +/** @file + TPM Platform Hierarchy configuration library. + + This library provides functions for customizing the TPM's Platform Hierarchy + Authorization Value (platformAuth) and Platform Hierarchy Authorization + Policy (platformPolicy) can be defined through this function. + +Copyright (c) 2019, Intel Corporation. All rights reserved. +Copyright (c) Microsoft Corporation. +SPDX-License-Identifier: BSD-2-Clause-Patent + +**/ + +#ifndef _TPM_PLATFORM_HIERARCHY_LIB_H_ +#define _TPM_PLATFORM_HIERARCHY_LIB_H_ + +/** + This service will perform the TPM Platform Hierarchy configuration at the SmmReadyToLock event. + +**/ +VOID +EFIAPI +ConfigureTpmPlatformHierarchy ( + VOID + ); + +#endif diff --git a/OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.c b/OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.c new file mode 100644 index 0000000000..ba2d99bb53 --- /dev/null +++ b/OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.c @@ -0,0 +1,210 @@ +/** @file + TPM Platform Hierarchy configuration library. + + This library provides functions for customizing the TPM's Platform Hierarchy + Authorization Value (platformAuth) and Platform Hierarchy Authorization + Policy (platformPolicy) can be defined through this function. + + Copyright (c) 2019, Intel Corporation. All rights reserved. + Copyright (c) Microsoft Corporation. + SPDX-License-Identifier: BSD-2-Clause-Patent + + @par Specification Reference: + <a href="https://trustedcomputinggroup.org/resource/tcg-tpm-v2-0-provisioning-guidance/" rel="noreferrer" target="_blank" moz-do-not-send="true">https://trustedcomputinggroup.org/resource/tcg-tpm-v2-0-provisioning-guidance/</a> +**/ + +#include <Uefi.h> + +#include <Library/BaseMemoryLib.h> +#include <Library/DebugLib.h> +#include <Library/MemoryAllocationLib.h> +#include <Library/RngLib.h> +#include <Library/Tpm2CommandLib.h> +#include <Library/Tpm2DeviceLib.h> + +// +// The authorization value may be no larger than the digest produced by the hash +// algorithm used for context integrity. +// +#define MAX_NEW_AUTHORIZATION_SIZE SHA512_DIGEST_SIZE + +UINT16 mAuthSize; + +/** + Generate high-quality entropy source through RDRAND. + + @param[in] Length Size of the buffer, in bytes, to fill with. + @param[out] Entropy Pointer to the buffer to store the entropy data. + + @retval EFI_SUCCESS Entropy generation succeeded. + @retval EFI_NOT_READY Failed to request random data. + +**/ +EFI_STATUS +EFIAPI +RdRandGenerateEntropy ( + IN UINTN Length, + OUT UINT8 *Entropy + ) +{ + EFI_STATUS Status; + UINTN BlockCount; + UINT64 Seed[2]; + UINT8 *Ptr; + + Status = EFI_NOT_READY; + BlockCount = Length / 64; + Ptr = (UINT8 *)Entropy; + + // + // Generate high-quality seed for DRBG Entropy + // + while (BlockCount > 0) { + Status = GetRandomNumber128 (Seed); + if (EFI_ERROR (Status)) { + return Status; + } + CopyMem (Ptr, Seed, 64); </blockquote> <div> </div> <div>This looks like it's copying past the Seed buffer, which is 2 * sizeof(u64) = 16. </div> </div> </div> </blockquote> Ha! Thanks for looking at this. Those seem to be the pitfalls of blindly importing code from edk2-platforms. Now the question is whether to leave it broken in edk2-platforms or fix it there first before trying to import it to edk2. In the interest of time I'd rather fix it here. Obviously the BlockCount is also wrong. <blockquote type="cite" cite="mid:CAMxuvayQeBK1GXSMjF3ErnxTwk05o7YRO0y2Fo2g1JUxG2tZcw@mail.gmail.com"> <div dir="ltr"> <div class="gmail_quote"> <div> </div> <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + + BlockCount--; + Ptr = Ptr + 64; + } + + // + // Populate the remained data as request. + // + Status = GetRandomNumber128 (Seed); + if (EFI_ERROR (Status)) { + return Status; + } + CopyMem (Ptr, Seed, (Length % 64)); </blockquote> <div> </div> <div>And then again.</div> <div> </div> <div>Isn't there a better way to fill a buffer with random data in edk2?</div> </div> </div> </blockquote> I don't know. On ARM it *looks like* the path goes down to an assembly instruction getting 64bit random number from the hardware: MdePkg/Library/BaseRngLib/AArch64/ArmRng.asm On x86 it will end up calling GenerateRandomNumberViaNist800Algorithm: MdePkg/Library/DxeRngLib/DxeRngLib.c CryptoPkg/Drvier/Crypto.c has this here: BOOLEAN EFIAPI CryptoServiceRandomSeed ( IN CONST UINT8 *Seed OPTIONAL, IN UINTN SeedSize ) { return CALL_BASECRYPTLIB (Random.Services.Seed, RandomSeed, (Seed, SeedSize) } and this one: BOOLEAN EFIAPI CryptoServiceRandomBytes ( OUT UINT8 *Output, IN UINTN Size ) { return CALL_BASECRYPTLIB (Random.Services.Bytes, RandomBytes, (Output, Size) } Those are pseudorandom numbers. I don't know about others. <blockquote type="cite" cite="mid:CAMxuvayQeBK1GXSMjF3ErnxTwk05o7YRO0y2Fo2g1JUxG2tZcw@mail.gmail.com"> <div dir="ltr"> <div class="gmail_quote"> <div> </div> <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + + return Status; +} + +/** + This function returns the maximum size of TPM2B_AUTH; this structure is used for an authorization value + and limits an authValue to being no larger than the largest digest produced by a TPM. + + @param[out] AuthSize Tpm2 Auth size + + @retval EFI_SUCCESS Auth size returned. + @retval EFI_DEVICE_ERROR Can not return platform auth due to device error. + +**/ +EFI_STATUS +EFIAPI +GetAuthSize ( + OUT UINT16 *AuthSize + ) +{ + EFI_STATUS Status; + TPML_PCR_SELECTION Pcrs; + UINTN Index; + UINT16 DigestSize; + + Status = EFI_SUCCESS; + + while (mAuthSize == 0) { </blockquote> <div> </div> <div>This is a bit odd, but ok.</div> <div> </div> <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + + mAuthSize = SHA1_DIGEST_SIZE; + ZeroMem (&Pcrs, sizeof (TPML_PCR_SELECTION)); + Status = Tpm2GetCapabilityPcrs (&Pcrs); + + if (EFI_ERROR (Status)) { + DEBUG ((DEBUG_ERROR, "Tpm2GetCapabilityPcrs fail!\n")); + break; + } + + DEBUG ((DEBUG_ERROR, "Tpm2GetCapabilityPcrs - %08x\n", Pcrs.count)); + + for (Index = 0; Index < Pcrs.count; Index++) { + DEBUG ((DEBUG_ERROR, "alg - %x\n", Pcrs.pcrSelections[Index].hash)); + + switch (Pcrs.pcrSelections[Index].hash) { + case TPM_ALG_SHA1: + DigestSize = SHA1_DIGEST_SIZE; + break; + case TPM_ALG_SHA256: + DigestSize = SHA256_DIGEST_SIZE; + break; + case TPM_ALG_SHA384: + DigestSize = SHA384_DIGEST_SIZE; + break; + case TPM_ALG_SHA512: + DigestSize = SHA512_DIGEST_SIZE; + break; + case TPM_ALG_SM3_256: + DigestSize = SM3_256_DIGEST_SIZE; + break; + default: + DigestSize = SHA1_DIGEST_SIZE; + break; + } + + if (DigestSize > mAuthSize) { + mAuthSize = DigestSize; + } + } + break; + } + + *AuthSize = mAuthSize; + return Status; +} + +/** + Set PlatformAuth to random value. +**/ +VOID +RandomizePlatformAuth ( + VOID + ) +{ + EFI_STATUS Status; + UINT16 AuthSize; + UINT8 *Rand; + UINTN RandSize; + TPM2B_AUTH NewPlatformAuth; + + // + // Send Tpm2HierarchyChange Auth with random value to avoid PlatformAuth being null + // + + GetAuthSize (&AuthSize); + + ZeroMem (NewPlatformAuth.buffer, AuthSize); + NewPlatformAuth.size = AuthSize; + + // + // Allocate one buffer to store random data. + // + RandSize = MAX_NEW_AUTHORIZATION_SIZE; + Rand = AllocatePool (RandSize); + + RdRandGenerateEntropy (RandSize, Rand); + CopyMem (NewPlatformAuth.buffer, Rand, AuthSize); </blockquote> <div> </div> <div>Why generate random data for MAX_NEW_AUTHORIZATION to only copy a subset after?</div> <div> </div> <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + + FreePool (Rand); + + // + // Send Tpm2HierarchyChangeAuth command with the new Auth value + // + Status = Tpm2HierarchyChangeAuth (TPM_RH_PLATFORM, NULL, &NewPlatformAuth); + DEBUG ((DEBUG_INFO, "Tpm2HierarchyChangeAuth Result: - %r\n", Status)); + ZeroMem (NewPlatformAuth.buffer, AuthSize); + ZeroMem (Rand, RandSize); </blockquote> <div> </div> <div>Isn't Rand free at this point?</div> </div> </div> </blockquote> Indeed! <blockquote type="cite" cite="mid:CAMxuvayQeBK1GXSMjF3ErnxTwk05o7YRO0y2Fo2g1JUxG2tZcw@mail.gmail.com"> <div dir="ltr"> <div class="gmail_quote"> <div> </div> <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> +} + +/** + This service defines the configuration of the Platform Hierarchy Authorization Value (platformAuth) + and Platform Hierarchy Authorization Policy (platformPolicy) + +**/ +VOID +EFIAPI +ConfigureTpmPlatformHierarchy ( + ) +{ + RandomizePlatformAuth (); +} diff --git a/OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.inf b/OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.inf new file mode 100644 index 0000000000..a413e02302 --- /dev/null +++ b/OvmfPkg/Library/PeiDxeTpmPlatformHierarchyLib/PeiDxeTpmPlatformHierarchyLib.inf @@ -0,0 +1,40 @@ +### @file +# +# TPM Platform Hierarchy configuration library. +# +# This library provides functions for customizing the TPM's Platform Hierarchy +# Authorization Value (platformAuth) and Platform Hierarchy Authorization +# Policy (platformPolicy) can be defined through this function. +# +# Copyright (c) 2019, Intel Corporation. All rights reserved. +# Copyright (c) Microsoft Corporation. +# +# SPDX-License-Identifier: BSD-2-Clause-Patent +# +### + +[Defines] + INF_VERSION = 0x00010005 + BASE_NAME = PeiDxeTpmPlatformHierarchyLib + FILE_GUID = 7794F92C-4E8E-4E57-9E4A-49A0764C7D73 + MODULE_TYPE = PEIM + VERSION_STRING = 1.0 + LIBRARY_CLASS = TpmPlatformHierarchyLib|PEIM DXE_DRIVER + +[LibraryClasses] + BaseLib + BaseMemoryLib + DebugLib + MemoryAllocationLib + RngLib + Tpm2CommandLib + Tpm2DeviceLib + +[Packages] + MdePkg/MdePkg.dec + MdeModulePkg/MdeModulePkg.dec + SecurityPkg/SecurityPkg.dec + CryptoPkg/CryptoPkg.dec + +[Sources] + PeiDxeTpmPlatformHierarchyLib.c -- 2.31.1 </blockquote> </div> </div> </blockquote> </body> </html> <div width="1" style="color:white;clear:both">_._,_._,_</div> <hr> Groups.io Links: You receive all messages sent to this group. <a target="_blank" href="https://edk2.groups.io/g/devel/message/79188">View/Reply Online (#79188)</a> | | <a target="_blank" href="https://groups.io/mt/84798631/1813853">Mute This Topic</a> | <a href="https://edk2.groups.io/g/devel/post">New Topic</a> <a href="https://edk2.groups.io/g/devel/editsub/1813853">Your Subscription</a> | <a href="mailto:devel+owner@edk2.groups.io">Contact Group Owner</a> | <a href="https://edk2.groups.io/g/devel/unsub">Unsubscribe</a> [edk2-devel-archive@redhat.com] <div width="1" style="color:white;clear:both">_._,_._,_</div>