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/* $Id: tpm-linux.cpp $ */
/** @file
* IPRT - Trusted Platform Module (TPM) access, Linux variant.
*/
/*
* Copyright (C) 2021-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#define LOG_GROUP RTLOGGROUP_DEFAULT
#include <iprt/tpm.h>
#include <iprt/assertcompile.h>
#include <iprt/asm.h>
#include <iprt/err.h>
#include <iprt/file.h>
#include <iprt/log.h>
#include <iprt/mem.h>
#include <iprt/string.h>
#include <iprt/linux/sysfs.h>
/*********************************************************************************************************************************
* Defined Constants And Macros *
*********************************************************************************************************************************/
/*********************************************************************************************************************************
* Structures and Typedefs *
*********************************************************************************************************************************/
/**
* Internal TPM instance data.
*/
typedef struct RTTPMINT
{
/** Handle to the /dev/tpmX device. */
RTFILE hTpmDev;
/** Handle to the sysfs cancel interface. */
RTFILE hTpmCancel;
/** The deduced TPM version. */
RTTPMVERSION enmTpmVers;
/** Flag whether a request is currently being executed. */
volatile bool fReqExec;
} RTTPMINT;
/** Pointer to the internal TPM instance data. */
typedef RTTPMINT *PRTTPMINT;
/*********************************************************************************************************************************
* Internal Functions *
*********************************************************************************************************************************/
RTDECL(int) RTTpmOpen(PRTTPM phTpm, uint32_t idTpm)
{
AssertPtrReturn(phTpm, VERR_INVALID_POINTER);
if (idTpm == RTTPM_ID_DEFAULT)
idTpm = 0;
int rc = VINF_SUCCESS;
PRTTPMINT pThis = (PRTTPMINT)RTMemAllocZ(sizeof(*pThis));
if (pThis)
{
pThis->hTpmDev = NIL_RTFILE;
pThis->hTpmCancel = NIL_RTFILE;
pThis->enmTpmVers = RTTPMVERSION_UNKNOWN;
pThis->fReqExec = false;
rc = RTFileOpenF(&pThis->hTpmDev, RTFILE_O_OPEN | RTFILE_O_READWRITE | RTFILE_O_DENY_NONE,
"/dev/tpm%u", idTpm);
if (RT_SUCCESS(rc))
{
/* Open the sysfs path to cancel a request, either /sys/class/tpm/tpmX/device/cancel or /sys/class/misc/tpmX/device/cancel. */
rc = RTFileOpenF(&pThis->hTpmCancel, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE,
"/sys/class/tpm/tpm%u/device/cancel", idTpm);
if (rc == VERR_FILE_NOT_FOUND)
rc = RTFileOpenF(&pThis->hTpmCancel, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE,
"/sys/class/misc/tpm%u/device/cancel", idTpm);
if ( RT_SUCCESS(rc)
|| rc == VERR_FILE_NOT_FOUND)
{
/* Try to figure out the TPM version. */
int64_t iVersion = 0;
rc = RTLinuxSysFsReadIntFile(10 /*uBase*/, &iVersion, "/sys/class/tpm/tpm%u/tpm_version_major", idTpm);
if (rc == VERR_FILE_NOT_FOUND)
rc = RTLinuxSysFsReadIntFile(10 /*uBase*/, &iVersion, "/sys/class/misc/tpm%u/tpm_version_major", idTpm);
if (RT_SUCCESS(rc))
{
if (iVersion == 1)
pThis->enmTpmVers = RTTPMVERSION_1_2;
else if (iVersion == 2)
pThis->enmTpmVers = RTTPMVERSION_2_0;
}
*phTpm = pThis;
return VINF_SUCCESS;
}
RTFileClose(pThis->hTpmDev);
pThis->hTpmDev = NIL_RTFILE;
}
RTMemFree(pThis);
}
else
rc = VERR_NO_MEMORY;
return rc;
}
RTDECL(int) RTTpmClose(RTTPM hTpm)
{
PRTTPMINT pThis = hTpm;
AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
RTFileClose(pThis->hTpmDev);
if (pThis->hTpmCancel != NIL_RTFILE)
RTFileClose(pThis->hTpmCancel);
pThis->hTpmDev = NIL_RTFILE;
pThis->hTpmCancel = NIL_RTFILE;
RTMemFree(pThis);
return VINF_SUCCESS;
}
RTDECL(RTTPMVERSION) RTTpmGetVersion(RTTPM hTpm)
{
PRTTPMINT pThis = hTpm;
AssertPtrReturn(pThis, RTTPMVERSION_INVALID);
return pThis->enmTpmVers;
}
RTDECL(uint32_t) RTTpmGetLocalityMax(RTTPM hTpm)
{
RT_NOREF(hTpm);
return 0; /* On Linux only TPM locality 0 is supported. */
}
RTDECL(int) RTTpmReqCancel(RTTPM hTpm)
{
PRTTPMINT pThis = hTpm;
AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
if (pThis->hTpmCancel == NIL_RTFILE)
return VERR_NOT_SUPPORTED;
if (ASMAtomicReadBool(&pThis->fReqExec))
{
uint8_t bCancel = '-';
return RTFileWrite(pThis->hTpmCancel, &bCancel, sizeof(bCancel), NULL /*pcbWritten*/);
}
return VINF_SUCCESS;
}
RTDECL(int) RTTpmReqExec(RTTPM hTpm, uint8_t bLoc, const void *pvReq, size_t cbReq,
void *pvResp, size_t cbRespMax, size_t *pcbResp)
{
PRTTPMINT pThis = hTpm;
AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
AssertPtrReturn(pvReq, VERR_INVALID_POINTER);
AssertPtrReturn(pvResp, VERR_INVALID_POINTER);
AssertReturn(cbReq && cbRespMax, VERR_INVALID_PARAMETER);
AssertReturn(bLoc == 0, VERR_NOT_SUPPORTED); /** @todo There doesn't seem to be a way to use a different locality. */
/* The request has to be supplied by a single blocking write. */
ASMAtomicXchgBool(&pThis->fReqExec, true);
int rc = RTFileWrite(pThis->hTpmDev, pvReq, cbReq, NULL /*pcbWritten*/);
if (RT_SUCCESS(rc))
{
size_t cbResp = 0;
/* The response has to be retrieved in a single read as well. */
rc = RTFileRead(pThis->hTpmDev, pvResp, cbRespMax, &cbResp);
ASMAtomicXchgBool(&pThis->fReqExec, false);
if (RT_SUCCESS(rc))
{
/* Check whether the response is complete. */
if ( cbResp >= sizeof(TPMRESPHDR)
&& RTTpmRespGetSz((PCTPMRESPHDR)pvResp) == cbResp)
{
if (pcbResp)
*pcbResp = cbResp;
}
else
rc = VERR_BUFFER_OVERFLOW;
}
}
return rc;
}
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