Rather than hard coding the buffer size in the tpm_passthrough backend read the TPM I/O buffer size from the host device. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
291 lines
9 KiB
C
291 lines
9 KiB
C
/*
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* TPM utility functions
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*
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* Copyright (c) 2010 - 2015 IBM Corporation
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* Authors:
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* Stefan Berger <stefanb@us.ibm.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>
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*/
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#include "qemu/osdep.h"
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#include "qemu/error-report.h"
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#include "tpm_util.h"
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#include "tpm_int.h"
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#include "exec/memory.h"
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#define DEBUG_TPM 0
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#define DPRINTF(fmt, ...) do { \
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if (DEBUG_TPM) { \
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fprintf(stderr, "tpm-util:"fmt"\n", ## __VA_ARGS__); \
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} \
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} while (0)
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/*
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* Write an error message in the given output buffer.
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*/
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void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len)
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{
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if (out_len >= sizeof(struct tpm_resp_hdr)) {
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struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out;
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resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND);
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resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr));
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resp->errcode = cpu_to_be32(TPM_FAIL);
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}
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}
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bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len)
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{
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struct tpm_req_hdr *hdr = (struct tpm_req_hdr *)in;
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if (in_len >= sizeof(*hdr)) {
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return (be32_to_cpu(hdr->ordinal) == TPM_ORD_ContinueSelfTest);
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}
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return false;
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}
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/*
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* Send request to a TPM device. We expect a response within one second.
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*/
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static int tpm_util_request(int fd,
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unsigned char *request,
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size_t requestlen,
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unsigned char *response,
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size_t responselen)
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{
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struct tpm_resp_hdr *resp;
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fd_set readfds;
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int n;
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struct timeval tv = {
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.tv_sec = 1,
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.tv_usec = 0,
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};
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n = write(fd, request, requestlen);
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if (n < 0) {
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return -errno;
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}
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if (n != requestlen) {
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return -EFAULT;
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}
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FD_ZERO(&readfds);
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FD_SET(fd, &readfds);
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/* wait for a second */
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n = select(fd + 1, &readfds, NULL, NULL, &tv);
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if (n != 1) {
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return -errno;
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}
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n = read(fd, response, responselen);
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if (n < sizeof(struct tpm_resp_hdr)) {
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return -EFAULT;
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}
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resp = (struct tpm_resp_hdr *)response;
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/* check the header */
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if (be32_to_cpu(resp->len) != n) {
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return -EMSGSIZE;
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}
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return 0;
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}
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/*
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* A basic test of a TPM device. We expect a well formatted response header
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* (error response is fine).
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*/
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static int tpm_util_test(int fd,
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unsigned char *request,
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size_t requestlen,
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uint16_t *return_tag)
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{
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struct tpm_resp_hdr *resp;
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unsigned char buf[1024];
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ssize_t ret;
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ret = tpm_util_request(fd, request, requestlen,
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buf, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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resp = (struct tpm_resp_hdr *)buf;
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*return_tag = be16_to_cpu(resp->tag);
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return 0;
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}
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/*
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* Probe for the TPM device in the back
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* Returns 0 on success with the version of the probed TPM set, 1 on failure.
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*/
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int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)
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{
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/*
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* Sending a TPM1.2 command to a TPM2 should return a TPM1.2
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* header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e)
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*
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* Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the
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* header.
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* Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag
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* in the header and an error code.
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*/
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const struct tpm_req_hdr test_req = {
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.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
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.len = cpu_to_be32(sizeof(test_req)),
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.ordinal = cpu_to_be32(TPM_ORD_GetTicks),
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};
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const struct tpm_req_hdr test_req_tpm2 = {
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.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
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.len = cpu_to_be32(sizeof(test_req_tpm2)),
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.ordinal = cpu_to_be32(TPM2_CC_ReadClock),
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};
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uint16_t return_tag;
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int ret;
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/* Send TPM 2 command */
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ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req_tpm2,
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sizeof(test_req_tpm2), &return_tag);
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/* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */
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if (!ret && return_tag == TPM2_ST_NO_SESSIONS) {
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*tpm_version = TPM_VERSION_2_0;
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return 0;
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}
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/* Send TPM 1.2 command */
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ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req,
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sizeof(test_req), &return_tag);
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if (!ret && return_tag == TPM_TAG_RSP_COMMAND) {
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*tpm_version = TPM_VERSION_1_2;
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/* this is a TPM 1.2 */
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return 0;
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}
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*tpm_version = TPM_VERSION_UNSPEC;
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return 1;
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}
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int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version,
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size_t *buffersize)
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{
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unsigned char buf[1024];
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int ret;
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switch (tpm_version) {
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case TPM_VERSION_1_2: {
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const struct tpm_req_get_buffer_size {
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struct tpm_req_hdr hdr;
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uint32_t capability;
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uint32_t len;
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uint32_t subcap;
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} QEMU_PACKED tpm_get_buffer_size = {
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.hdr = {
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.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
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.len = cpu_to_be32(sizeof(tpm_get_buffer_size)),
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.ordinal = cpu_to_be32(TPM_ORD_GetCapability),
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},
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.capability = cpu_to_be32(TPM_CAP_PROPERTY),
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.len = cpu_to_be32(sizeof(uint32_t)),
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.subcap = cpu_to_be32(TPM_CAP_PROP_INPUT_BUFFER),
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};
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struct tpm_resp_get_buffer_size {
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struct tpm_resp_hdr hdr;
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uint32_t len;
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uint32_t buffersize;
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} QEMU_PACKED *tpm_resp = (struct tpm_resp_get_buffer_size *)buf;
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ret = tpm_util_request(tpm_fd, (unsigned char *)&tpm_get_buffer_size,
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sizeof(tpm_get_buffer_size), buf, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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if (be32_to_cpu(tpm_resp->hdr.len) != sizeof(*tpm_resp) ||
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be32_to_cpu(tpm_resp->len) != sizeof(uint32_t)) {
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DPRINTF("tpm_resp->hdr.len = %u, expected = %zu\n",
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be32_to_cpu(tpm_resp->hdr.len), sizeof(*tpm_resp));
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DPRINTF("tpm_resp->len = %u, expected = %zu\n",
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be32_to_cpu(tpm_resp->len), sizeof(uint32_t));
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error_report("tpm_util: Got unexpected response to "
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"TPM_GetCapability; errcode: 0x%x",
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be32_to_cpu(tpm_resp->hdr.errcode));
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return -EFAULT;
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}
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*buffersize = be32_to_cpu(tpm_resp->buffersize);
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break;
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}
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case TPM_VERSION_2_0: {
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const struct tpm2_req_get_buffer_size {
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struct tpm_req_hdr hdr;
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uint32_t capability;
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uint32_t property;
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uint32_t count;
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} QEMU_PACKED tpm2_get_buffer_size = {
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.hdr = {
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.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
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.len = cpu_to_be32(sizeof(tpm2_get_buffer_size)),
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.ordinal = cpu_to_be32(TPM2_CC_GetCapability),
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},
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.capability = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES),
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.property = cpu_to_be32(TPM2_PT_MAX_COMMAND_SIZE),
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.count = cpu_to_be32(2), /* also get TPM2_PT_MAX_RESPONSE_SIZE */
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};
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struct tpm2_resp_get_buffer_size {
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struct tpm_resp_hdr hdr;
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uint8_t more;
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uint32_t capability;
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uint32_t count;
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uint32_t property1;
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uint32_t value1;
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uint32_t property2;
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uint32_t value2;
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} QEMU_PACKED *tpm2_resp = (struct tpm2_resp_get_buffer_size *)buf;
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ret = tpm_util_request(tpm_fd, (unsigned char *)&tpm2_get_buffer_size,
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sizeof(tpm2_get_buffer_size), buf, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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if (be32_to_cpu(tpm2_resp->hdr.len) != sizeof(*tpm2_resp) ||
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be32_to_cpu(tpm2_resp->count) != 2) {
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DPRINTF("tpm2_resp->hdr.len = %u, expected = %zu\n",
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be32_to_cpu(tpm2_resp->hdr.len), sizeof(*tpm2_resp));
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DPRINTF("tpm2_resp->len = %u, expected = %u\n",
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be32_to_cpu(tpm2_resp->count), 2);
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error_report("tpm_util: Got unexpected response to "
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"TPM2_GetCapability; errcode: 0x%x",
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be32_to_cpu(tpm2_resp->hdr.errcode));
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return -EFAULT;
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}
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*buffersize = MAX(be32_to_cpu(tpm2_resp->value1),
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be32_to_cpu(tpm2_resp->value2));
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break;
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}
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case TPM_VERSION_UNSPEC:
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return -EFAULT;
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}
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DPRINTF("buffersize of device: %zu\n", *buffersize);
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return 0;
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}
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