wolfTPM/examples/wrap/getrandom.c

137 lines
3.6 KiB
C

/* getrandom.c
*
* Copyright (C) 2006-2026 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 3 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 02110-1335, USA
*/
/* Example for getting random bytes from the TPM */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <wolftpm/tpm2_wrap.h>
#ifndef WOLFTPM2_NO_WRAPPER
#include <hal/tpm_io.h>
#include <examples/tpm_test.h>
#include <examples/wrap/wrap_test.h>
#include <stdio.h>
/* Default and maximum number of random bytes to request */
#define GETRANDOM_DEFAULT_BYTES 32
#define GETRANDOM_MAX_BYTES 256
/******************************************************************************/
/* --- BEGIN TPM2 Get Random example -- */
/******************************************************************************/
static void usage(void)
{
printf("Expected Usage:\n");
printf("./examples/wrap/getrandom [bytes]\n");
printf("* bytes is the number of random bytes to request "
"(default %d, max %d)\n", GETRANDOM_DEFAULT_BYTES, GETRANDOM_MAX_BYTES);
}
int TPM2_GetRandom_Example(void* userCtx, int argc, char* argv[])
{
int rc;
WOLFTPM2_DEV dev;
byte buf[GETRANDOM_MAX_BYTES];
word32 len = GETRANDOM_DEFAULT_BYTES;
word32 i;
int lenArg;
if (argc > 1) {
if (XSTRCMP(argv[1], "-?") == 0 ||
XSTRCMP(argv[1], "-h") == 0 ||
XSTRCMP(argv[1], "--help") == 0) {
usage();
return 0;
}
lenArg = XATOI(argv[1]);
if (lenArg < 0) {
printf("Invalid length %d\n", lenArg);
return BAD_FUNC_ARG;
}
len = (word32)lenArg;
if (len == 0) {
len = GETRANDOM_DEFAULT_BYTES;
}
if (len > GETRANDOM_MAX_BYTES) {
len = GETRANDOM_MAX_BYTES;
}
}
printf("TPM2 Get Random Example (%u bytes)\n", len);
XMEMSET(buf, 0, sizeof(buf));
/* Init the TPM2 device */
rc = wolfTPM2_Init(&dev, TPM2_IoCb, userCtx);
if (rc != 0) {
printf("wolfTPM2_Init failed 0x%x: %s\n", rc, TPM2_GetRCString(rc));
return rc;
}
rc = wolfTPM2_GetRandom(&dev, buf, len);
if (rc != 0) {
printf("wolfTPM2_GetRandom failed 0x%x: %s\n", rc,
wolfTPM2_GetRCString(rc));
goto exit;
}
printf("Random bytes:\n");
for (i = 0; i < len; i++) {
printf("%02x", buf[i]);
}
printf("\n");
exit:
wolfTPM2_Cleanup(&dev);
return rc;
}
/******************************************************************************/
/* --- END TPM2 Get Random example -- */
/******************************************************************************/
#endif /* !WOLFTPM2_NO_WRAPPER */
#ifndef NO_MAIN_DRIVER
int main(int argc, char* argv[])
{
int rc = -1;
#ifndef WOLFTPM2_NO_WRAPPER
rc = TPM2_GetRandom_Example(NULL, argc, argv);
#else
(void)argc;
(void)argv;
printf("Wrapper code not compiled in\n");
#endif
return rc;
}
#endif /* !NO_MAIN_DRIVER */