128 lines
3.5 KiB
C
128 lines
3.5 KiB
C
/*
|
|
* TPM utility functions
|
|
*
|
|
* Copyright (c) 2010 - 2015 IBM Corporation
|
|
* Authors:
|
|
* Stefan Berger <stefanb@us.ibm.com>
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, see <http://www.gnu.org/licenses/>
|
|
*/
|
|
|
|
#include "qemu/osdep.h"
|
|
#include "tpm_util.h"
|
|
#include "tpm_int.h"
|
|
|
|
/*
|
|
* A basic test of a TPM device. We expect a well formatted response header
|
|
* (error response is fine) within one second.
|
|
*/
|
|
static int tpm_util_test(int fd,
|
|
unsigned char *request,
|
|
size_t requestlen,
|
|
uint16_t *return_tag)
|
|
{
|
|
struct tpm_resp_hdr *resp;
|
|
fd_set readfds;
|
|
int n;
|
|
struct timeval tv = {
|
|
.tv_sec = 1,
|
|
.tv_usec = 0,
|
|
};
|
|
unsigned char buf[1024];
|
|
|
|
n = write(fd, request, requestlen);
|
|
if (n < 0) {
|
|
return errno;
|
|
}
|
|
if (n != requestlen) {
|
|
return EFAULT;
|
|
}
|
|
|
|
FD_ZERO(&readfds);
|
|
FD_SET(fd, &readfds);
|
|
|
|
/* wait for a second */
|
|
n = select(fd + 1, &readfds, NULL, NULL, &tv);
|
|
if (n != 1) {
|
|
return errno;
|
|
}
|
|
|
|
n = read(fd, &buf, sizeof(buf));
|
|
if (n < sizeof(struct tpm_resp_hdr)) {
|
|
return EFAULT;
|
|
}
|
|
|
|
resp = (struct tpm_resp_hdr *)buf;
|
|
/* check the header */
|
|
if (be32_to_cpu(resp->len) != n) {
|
|
return EBADMSG;
|
|
}
|
|
|
|
*return_tag = be16_to_cpu(resp->tag);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Probe for the TPM device in the back
|
|
* Returns 0 on success with the version of the probed TPM set, 1 on failure.
|
|
*/
|
|
int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)
|
|
{
|
|
/*
|
|
* Sending a TPM1.2 command to a TPM2 should return a TPM1.2
|
|
* header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e)
|
|
*
|
|
* Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the
|
|
* header.
|
|
* Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag
|
|
* in the header and an error code.
|
|
*/
|
|
const struct tpm_req_hdr test_req = {
|
|
.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
|
|
.len = cpu_to_be32(sizeof(test_req)),
|
|
.ordinal = cpu_to_be32(TPM_ORD_GetTicks),
|
|
};
|
|
|
|
const struct tpm_req_hdr test_req_tpm2 = {
|
|
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
|
|
.len = cpu_to_be32(sizeof(test_req_tpm2)),
|
|
.ordinal = cpu_to_be32(TPM2_CC_ReadClock),
|
|
};
|
|
uint16_t return_tag;
|
|
int ret;
|
|
|
|
/* Send TPM 2 command */
|
|
ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req_tpm2,
|
|
sizeof(test_req_tpm2), &return_tag);
|
|
/* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */
|
|
if (!ret && return_tag == TPM2_ST_NO_SESSIONS) {
|
|
*tpm_version = TPM_VERSION_2_0;
|
|
return 0;
|
|
}
|
|
|
|
/* Send TPM 1.2 command */
|
|
ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req,
|
|
sizeof(test_req), &return_tag);
|
|
if (!ret && return_tag == TPM_TAG_RSP_COMMAND) {
|
|
*tpm_version = TPM_VERSION_1_2;
|
|
/* this is a TPM 1.2 */
|
|
return 0;
|
|
}
|
|
|
|
*tpm_version = TPM_VERSION_UNSPEC;
|
|
|
|
return 1;
|
|
}
|