wolfTPM/examples/pcr/extend.c

/* extend.c
 *
 * Copyright (C) 2006-2020 wolfSSL Inc.
 *
 * This file is part of wolfTPM.
 *
 * wolfTPM 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * wolfTPM 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */

/* This is a helper tool for extending hash into a TPM2.0 PCR */

#include <wolftpm/tpm2_wrap.h>

#ifndef WOLFTPM2_NO_WOLFCRYPT
#include <wolfssl/wolfcrypt/hash.h>
#endif

#include <examples/pcr/extend.h>
#include <examples/tpm_io.h>
#include <examples/tpm_test.h>

#include <stdio.h>
#include <stdlib.h> /* strtol */


/******************************************************************************/
/* --- BEGIN TPM2.0 PCR Extend example tool  -- */
/******************************************************************************/

static void usage(void)
{
    printf("Expected usage:\n");
    printf("./examples/pcr/extend [pcr] [filename]\n");
    printf("* pcr is a PCR index between 0-23 (default 16)\n");
    printf("* filename points to file(data) to measure\n");
    printf("\tIf wolfTPM is built with --disable-wolfcrypt the file\n"
           "\tmust contain SHA256 digest ready for extend operation.\n"
           "\tOtherwise, the extend tool computes the hash using wolfcrypt.\n");
    printf("Demo usage without parameters, extends PCR16 with known hash.\n");
}

int TPM2_Extend_Test(void* userCtx, int argc, char *argv[])
{
    int i, pcrIndex, len, rc = -1;
    WOLFTPM2_DEV dev;
    /* Arbitrary user data provided through a file */
    const char *filename = NULL;
    FILE *dataFile = NULL;
    BYTE hash[TPM_SHA256_DIGEST_SIZE];
#ifndef WOLFTPM2_NO_WOLFCRYPT
    /* Using wolfcrypt to hash input data */
    BYTE dataBuffer[1024];
    Sha256 sha256;
#endif

    union {
#ifdef WOLFTPM_DEBUG_VERBOSE
        PCR_Read_In pcrRead;
#endif
        PCR_Extend_In pcrExtend;
        FlushContext_In flushCtx;
        byte maxInput[MAX_COMMAND_SIZE];
    } cmdIn;
#ifdef WOLFTPM_DEBUG_VERBOSE
    union {
        PCR_Read_Out pcrRead;
        byte maxOutput[MAX_RESPONSE_SIZE];
    } cmdOut;
#endif


    TPM_HANDLE sessionHandle = TPM_RH_NULL;
    TPMS_AUTH_COMMAND session[MAX_SESSION_NUM];

    if(argc == 3) {
        pcrIndex = strtol(argv[1], NULL, 10);
        if(pcrIndex < 0 || pcrIndex > 23) {
            printf("PCR index is out of range(0-23)\n");
            goto exit_badargs;
        }

        filename = argv[2];
        dataFile = fopen(filename, "rb");
        if(dataFile == NULL) {
            printf("Error opening file %s\n", filename);
            usage();
            goto exit_badargs;
        }
    }
    else if(argc == 1) {
        pcrIndex = 16; /* PCR16 is for DEBUG purposes, thus safe to use */
    }
    else {
        printf("Incorrect arguments\n");
        usage();
        goto exit_badargs;
    }

    printf("Demo how to extend data into a PCR (TPM2.0 measurement)\n");
    rc = wolfTPM2_Init(&dev, TPM2_IoCb, userCtx);
    if (rc != TPM_RC_SUCCESS) {
        printf("wolfTPM2_Init failed 0x%x: %s\n", rc, TPM2_GetRCString(rc));
        goto exit;
    }
    printf("wolfTPM2_Init: success\n");


    /* Define the default session auth that has NULL password */
    XMEMSET(session, 0, sizeof(session));
    session[0].sessionHandle = TPM_RS_PW;
    session[0].auth.size = 0; /* NULL Password */
    TPM2_SetSessionAuth(session);

    /* Prepare PCR Extend command */
    XMEMSET(&cmdIn.pcrExtend, 0, sizeof(cmdIn.pcrExtend));
    cmdIn.pcrExtend.pcrHandle = pcrIndex;
    cmdIn.pcrExtend.digests.count = 1;
    cmdIn.pcrExtend.digests.digests[0].hashAlg = TPM_ALG_SHA256;
    /* Prepare the hash from user file or predefined value */
    if(dataFile == NULL) {
        for (i=0; i<TPM_SHA256_DIGEST_SIZE; i++) {
            cmdIn.pcrExtend.digests.digests[0].digest.H[i] = i;
        }
    }
    else {
#ifndef WOLFTPM2_NO_WOLFCRYPT
        wc_InitSha256(&sha256);
        while(!feof(dataFile)) {
            len = fread(dataBuffer, 1, sizeof(dataBuffer), dataFile);
            if(len) {
                 wc_Sha256Update(&sha256, dataBuffer, len);
            }
        }
        wc_Sha256Final(&sha256, hash);
#else
        len = fread(hash, 1, TPM_SHA256_DIGEST_SIZE, dataFile);
        if(len != TPM_SHA256_DIGEST_SIZE) {
            printf("Error while reading SHA256 digest from file.\n");
            goto exit;
        }
#endif
        XMEMCPY(cmdIn.pcrExtend.digests.digests[0].digest.H,
                hash, TPM_SHA256_DIGEST_SIZE);
    }
    printf("Hash to be used for measurement:\n");
    for(i=0; i < TPM_SHA256_DIGEST_SIZE; i++)
        printf("%02X", cmdIn.pcrExtend.digests.digests[0].digest.H[i]);
    printf("\n");

    rc = TPM2_PCR_Extend(&cmdIn.pcrExtend);
    if (rc != TPM_RC_SUCCESS) {
        printf("TPM2_PCR_Extend failed 0x%x: %s\n", rc,
            TPM2_GetRCString(rc));
        goto exit;
    }
    printf("TPM2_PCR_Extend success\n");

#ifdef WOLFTPM_DEBUG_VERBOSE
    XMEMSET(&cmdIn.pcrRead, 0, sizeof(cmdIn.pcrRead));
    TPM2_SetupPCRSel(&cmdIn.pcrRead.pcrSelectionIn,
        TEST_WRAP_DIGEST, pcrIndex);
    rc = TPM2_PCR_Read(&cmdIn.pcrRead, &cmdOut.pcrRead);
    if (rc != TPM_RC_SUCCESS) {
        printf("TPM2_PCR_Read failed 0x%x: %s\n", rc, TPM2_GetRCString(rc));
        goto exit;
    }

    printf("PCR%d value:\n", pcrIndex);
    TPM2_PrintBin(cmdOut.pcrRead.pcrValues.digests[0].buffer,
                  cmdOut.pcrRead.pcrValues.digests[0].size);
#endif

exit:

    /* Close session */
    if (sessionHandle != TPM_RH_NULL) {
        cmdIn.flushCtx.flushHandle = sessionHandle;
        TPM2_FlushContext(&cmdIn.flushCtx);
    }

    wolfTPM2_Cleanup(&dev);

exit_badargs:

    if (dataFile != NULL) {
        fclose(dataFile);
    }

    return rc;
}

/******************************************************************************/
/* --- END TPM2.0 PCR Extend example tool -- */
/******************************************************************************/


#ifndef NO_MAIN_DRIVER
int main(int argc, char *argv[])
{
    int rc;

    rc = TPM2_Extend_Test(NULL, argc, argv);

    return rc;
}
#endif