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/********************************************************************************/
/* */
/* */
/* Written by Ken Goldman */
/* IBM Thomas J. Watson Research Center */
/* $Id: Attest_spt.c 1490 2019-07-26 21:13:22Z kgoldman $ */
/* */
/* Licenses and Notices */
/* */
/* 1. Copyright Licenses: */
/* */
/* - Trusted Computing Group (TCG) grants to the user of the source code in */
/* this specification (the "Source Code") a worldwide, irrevocable, */
/* nonexclusive, royalty free, copyright license to reproduce, create */
/* derivative works, distribute, display and perform the Source Code and */
/* derivative works thereof, and to grant others the rights granted herein. */
/* */
/* - The TCG grants to the user of the other parts of the specification */
/* (other than the Source Code) the rights to reproduce, distribute, */
/* display, and perform the specification solely for the purpose of */
/* developing products based on such documents. */
/* */
/* 2. Source Code Distribution Conditions: */
/* */
/* - Redistributions of Source Code must retain the above copyright licenses, */
/* this list of conditions and the following disclaimers. */
/* */
/* - Redistributions in binary form must reproduce the above copyright */
/* licenses, this list of conditions and the following disclaimers in the */
/* documentation and/or other materials provided with the distribution. */
/* */
/* 3. Disclaimers: */
/* */
/* - THE COPYRIGHT LICENSES SET FORTH ABOVE DO NOT REPRESENT ANY FORM OF */
/* LICENSE OR WAIVER, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, WITH */
/* RESPECT TO PATENT RIGHTS HELD BY TCG MEMBERS (OR OTHER THIRD PARTIES) */
/* THAT MAY BE NECESSARY TO IMPLEMENT THIS SPECIFICATION OR OTHERWISE. */
/* Contact TCG Administration (admin@trustedcomputinggroup.org) for */
/* information on specification licensing rights available through TCG */
/* membership agreements. */
/* */
/* - THIS SPECIFICATION IS PROVIDED "AS IS" WITH NO EXPRESS OR IMPLIED */
/* WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR */
/* FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, COMPLETENESS, OR */
/* NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, OR ANY WARRANTY */
/* OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. */
/* */
/* - Without limitation, TCG and its members and licensors disclaim all */
/* liability, including liability for infringement of any proprietary */
/* rights, relating to use of information in this specification and to the */
/* implementation of this specification, and TCG disclaims all liability for */
/* cost of procurement of substitute goods or services, lost profits, loss */
/* of use, loss of data or any incidental, consequential, direct, indirect, */
/* or special damages, whether under contract, tort, warranty or otherwise, */
/* arising in any way out of use or reliance upon this specification or any */
/* information herein. */
/* */
/* (c) Copyright IBM Corp. and others, 2016 - 2018 */
/* */
/********************************************************************************/
#include "Tpm.h"
#include "Attest_spt_fp.h"
/* 7.2.2 Functions */
/* 7.2.2.1 FillInAttestInfo() */
/* Fill in common fields of TPMS_ATTEST structure. */
void
FillInAttestInfo(
TPMI_DH_OBJECT signHandle, // IN: handle of signing object
TPMT_SIG_SCHEME *scheme, // IN/OUT: scheme to be used for signing
TPM2B_DATA *data, // IN: qualifying data
TPMS_ATTEST *attest // OUT: attest structure
)
{
OBJECT *signObject = HandleToObject(signHandle);
// Magic number
attest->magic = TPM_GENERATED_VALUE;
if(signObject == NULL)
{
// The name for a null handle is TPM_RH_NULL
// This is defined because UINT32_TO_BYTE_ARRAY does a cast. If the
// size of the cast is smaller than a constant, the compiler warns
// about the truncation of a constant value.
TPM_HANDLE nullHandle = TPM_RH_NULL;
attest->qualifiedSigner.t.size = sizeof(TPM_HANDLE);
UINT32_TO_BYTE_ARRAY(nullHandle, attest->qualifiedSigner.t.name);
}
else
{
// Certifying object qualified name
// if the scheme is anonymous, this is an empty buffer
if(CryptIsSchemeAnonymous(scheme->scheme))
attest->qualifiedSigner.t.size = 0;
else
attest->qualifiedSigner = signObject->qualifiedName;
}
// current clock in plain text
TimeFillInfo(&attest->clockInfo);
// Firmware version in plain text
attest->firmwareVersion = ((UINT64)gp.firmwareV1 << (sizeof(UINT32) * 8));
attest->firmwareVersion += gp.firmwareV2;
// Check the hierarchy of sign object. For NULL sign handle, the hierarchy
// will be TPM_RH_NULL
if((signObject == NULL)
|| (!signObject->attributes.epsHierarchy
&& !signObject->attributes.ppsHierarchy))
{
// For signing key that is not in platform or endorsement hierarchy,
// obfuscate the reset, restart and firmware version information
UINT64 obfuscation[2];
CryptKDFa(CONTEXT_INTEGRITY_HASH_ALG, &gp.shProof.b, OBFUSCATE_STRING,
&attest->qualifiedSigner.b, NULL, 128,
(BYTE *)&obfuscation[0], NULL, FALSE);
// Obfuscate data
attest->firmwareVersion += obfuscation[0];
attest->clockInfo.resetCount += (UINT32)(obfuscation[1] >> 32);
attest->clockInfo.restartCount += (UINT32)obfuscation[1];
}
// External data
if(CryptIsSchemeAnonymous(scheme->scheme))
attest->extraData.t.size = 0;
else
{
// If we move the data to the attestation structure, then it is not
// used in the signing operation except as part of the signed data
attest->extraData = *data;
data->t.size = 0;
}
}
/* 7.2.2.2 SignAttestInfo() */
/* Sign a TPMS_ATTEST structure. If signHandle is TPM_RH_NULL, a null signature is returned. */
/* Error Returns Meaning */
/* TPM_RC_ATTRIBUTES signHandle references not a signing key */
/* TPM_RC_SCHEME scheme is not compatible with signHandle type */
/* TPM_RC_VALUE digest generated for the given scheme is greater than the modulus of signHandle (for
an RSA key); invalid commit status or failed to generate r value (for an ECC key) */
TPM_RC
SignAttestInfo(
OBJECT *signKey, // IN: sign object
TPMT_SIG_SCHEME *scheme, // IN: sign scheme
TPMS_ATTEST *certifyInfo, // IN: the data to be signed
TPM2B_DATA *qualifyingData, // IN: extra data for the signing
// process
TPM2B_ATTEST *attest, // OUT: marshaled attest blob to be
// signed
TPMT_SIGNATURE *signature // OUT: signature
)
{
BYTE *buffer;
HASH_STATE hashState;
TPM2B_DIGEST digest;
TPM_RC result;
// Marshal TPMS_ATTEST structure for hash
buffer = attest->t.attestationData;
attest->t.size = TPMS_ATTEST_Marshal(certifyInfo, &buffer, NULL);
if(signKey == NULL)
{
signature->sigAlg = TPM_ALG_NULL;
result = TPM_RC_SUCCESS;
}
else
{
TPMI_ALG_HASH hashAlg;
// Compute hash
hashAlg = scheme->details.any.hashAlg;
// need to set the receive buffer to get something put in it
digest.t.size = sizeof(digest.t.buffer);
digest.t.size = CryptHashBlock(hashAlg, attest->t.size,
attest->t.attestationData,
digest.t.size, digest.t.buffer);
// If there is qualifying data, need to rehash the data
// hash(qualifyingData || hash(attestationData))
if(qualifyingData->t.size != 0)
{
CryptHashStart(&hashState, hashAlg);
CryptDigestUpdate2B(&hashState, &qualifyingData->b);
CryptDigestUpdate2B(&hashState, &digest.b);
CryptHashEnd2B(&hashState, &digest.b);
}
// Sign the hash. A TPM_RC_VALUE, TPM_RC_SCHEME, or
// TPM_RC_ATTRIBUTES error may be returned at this point
result = CryptSign(signKey, scheme, &digest, signature);
// Since the clock is used in an attestation, the state in NV is no longer
// "orderly" with respect to the data in RAM if the signature is valid
if(result == TPM_RC_SUCCESS)
{
// Command uses the clock so need to clear the orderly state if it is
// set.
result = NvClearOrderly();
}
}
return result;
}
/* 7.2.2.3 IsSigningObject() */
/* Checks to see if the object is OK for signing. This is here rather than in Object_spt.c because
all the attestation commands use this file but not Object_spt.c. */
/* Return Values Meaning */
/* TRUE object may sign */
/* FALSE object may not sign */
BOOL
IsSigningObject(
OBJECT *object // IN:
)
{
return ((object == NULL)
|| ((IS_ATTRIBUTE(object->publicArea.objectAttributes, TPMA_OBJECT, sign)
&& object->publicArea.type != TPM_ALG_SYMCIPHER)));
}
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