static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
const char *value;
value = qemu_opt_get(opts, "cancel-path");
if (value) {
tb->cancel_path = g_strdup(value);
}
value = qemu_opt_get(opts, "path");
if (!value) {
value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
}
tpm_pt->tpm_dev = g_strdup(value);
tb->path = g_strdup(tpm_pt->tpm_dev);
tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
if (tpm_pt->tpm_fd < 0) {
error_report("Cannot access TPM device using '%s': %s\n",
tpm_pt->tpm_dev, strerror(errno));
goto err_free_parameters;
}
if (tpm_passthrough_test_tpmdev(tpm_pt->tpm_fd)) {
error_report("'%s' is not a TPM device.\n",
tpm_pt->tpm_dev);
goto err_close_tpmdev;
}
return 0;
err_close_tpmdev:
qemu_close(tpm_pt->tpm_fd);
tpm_pt->tpm_fd = -1;
err_free_parameters:
g_free(tb->path);
tb->path = NULL;
g_free(tpm_pt->tpm_dev);
tpm_pt->tpm_dev = NULL;
return 1;
}
/*
* A basic test of a TPM device. We expect a well formatted response header
* (error response is fine) within one second.
*/
static int tpm_passthrough_test_tpmdev(int fd)
{
struct tpm_req_hdr req = {
.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
.len = cpu_to_be32(sizeof(req)),
.ordinal = cpu_to_be32(TPM_ORD_GetTicks),
};
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, &req, sizeof(req));
if (n < 0) {
return errno;
}
if (n != sizeof(req)) {
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 (be16_to_cpu(resp->tag) != TPM_TAG_RSP_COMMAND ||
be32_to_cpu(resp->len) != n) {
return EBADMSG;
}
return 0;
}
static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
{
const char *value;
struct stat statbuf;
value = qemu_opt_get(opts, "fd");
if (value) {
if (qemu_opt_get(opts, "path")) {
error_report("fd= is invalid with path=");
goto err_exit;
}
tb->s.tpm_pt->tpm_fd = qemu_parse_fd(value);
if (tb->s.tpm_pt->tpm_fd < 0) {
error_report("Illegal file descriptor for TPM device.\n");
goto err_exit;
}
tb->tpm_fd = &tb->s.tpm_pt->tpm_fd;
} else {
value = qemu_opt_get(opts, "path");
if (!value) {
value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
}
tb->s.tpm_pt->tpm_dev = g_strdup(value);
tb->path = g_strdup(value);
tb->s.tpm_pt->tpm_fd = open(tb->s.tpm_pt->tpm_dev, O_RDWR);
if (tb->s.tpm_pt->tpm_fd < 0) {
error_report("Cannot access TPM device using '%s'.\n",
tb->s.tpm_pt->tpm_dev);
goto err_free_parameters;
}
}
if (fstat(tb->s.tpm_pt->tpm_fd, &statbuf) != 0) {
error_report("Cannot determine file descriptor type for TPM "
"device: %s", strerror(errno));
goto err_close_tpmdev;
}
/* only allow character devices for now */
if (!S_ISCHR(statbuf.st_mode)) {
error_report("TPM file descriptor is not a character device");
goto err_free_parameters;
}
if (tpm_passthrough_test_tpmdev(tb->s.tpm_pt->tpm_fd)) {
error_report("Device is not a TPM.\n");
goto err_close_tpmdev;
}
return 0;
err_close_tpmdev:
close(tb->s.tpm_pt->tpm_fd);
tb->s.tpm_pt->tpm_fd = -1;
err_free_parameters:
g_free(tb->path);
tb->path = NULL;
g_free(tb->s.tpm_pt->tpm_dev);
tb->s.tpm_pt->tpm_dev = NULL;
err_exit:
return 1;
}
static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
{
TPMBackend *tb;
tb = g_new0(TPMBackend, 1);
tb->s.tpm_pt = g_new0(TPMPassthruState, 1);
tb->id = g_strdup(id);
tb->ops = &tpm_passthrough_driver;
if (tpm_passthrough_handle_device_opts(opts, tb)) {
goto err_exit;
}
return tb;
err_exit:
g_free(tb->id);
g_free(tb->s.tpm_pt);
g_free(tb);
return NULL;
}
static void tpm_passthrough_destroy(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = tb->s.tpm_pt;
tpm_backend_thread_end(&tpm_pt->tbt);
close(tpm_pt->tpm_fd);
g_free(tb->id);
g_free(tb->path);
g_free(tb->s.tpm_pt->tpm_dev);
g_free(tb->s.tpm_pt);
g_free(tb);
}
/*
* A basic test of a TPM device. We expect a well formatted response header
* (error response is fine) within one second.
*/
static int tpm_passthrough_test_tpmdev(int fd)
{
struct tpm_req_hdr req = {
.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
.len = cpu_to_be32(sizeof(req)),
.ordinal = cpu_to_be32(TPM_ORD_GetTicks),
};
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, &req, sizeof(req));
if (n < 0) {
return errno;
}
if (n != sizeof(req)) {
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 (be16_to_cpu(resp->tag) != TPM_TAG_RSP_COMMAND ||
be32_to_cpu(resp->len) != n) {
return EBADMSG;
}
return 0;
}
/*
* Unless path or file descriptor set has been provided by user,
* determine the sysfs cancel file following kernel documentation
* in Documentation/ABI/stable/sysfs-class-tpm.
* From /dev/tpm0 create /sys/class/misc/tpm0/device/cancel
*/
static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
int fd = -1;
char *dev;
char path[PATH_MAX];
if (tb->cancel_path) {
fd = qemu_open(tb->cancel_path, O_WRONLY);
if (fd < 0) {
error_report("Could not open TPM cancel path : %s",
strerror(errno));
}
return fd;
}
dev = strrchr(tpm_pt->tpm_dev, '/');
if (dev) {
dev++;
if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel",
dev) < sizeof(path)) {
fd = qemu_open(path, O_WRONLY);
if (fd >= 0) {
tb->cancel_path = g_strdup(path);
} else {
error_report("tpm_passthrough: Could not open TPM cancel "
"path %s : %s", path, strerror(errno));
}
}
} else {
error_report("tpm_passthrough: Bad TPM device path %s",
tpm_pt->tpm_dev);
}
return fd;
}
static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
const char *value;
value = qemu_opt_get(opts, "cancel-path");
tb->cancel_path = g_strdup(value);
value = qemu_opt_get(opts, "path");
if (!value) {
value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
}
tpm_pt->tpm_dev = g_strdup(value);
tb->path = g_strdup(tpm_pt->tpm_dev);
tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
if (tpm_pt->tpm_fd < 0) {
error_report("Cannot access TPM device using '%s': %s",
tpm_pt->tpm_dev, strerror(errno));
goto err_free_parameters;
}
if (tpm_passthrough_test_tpmdev(tpm_pt->tpm_fd)) {
error_report("'%s' is not a TPM device.",
tpm_pt->tpm_dev);
goto err_close_tpmdev;
}
return 0;
err_close_tpmdev:
qemu_close(tpm_pt->tpm_fd);
tpm_pt->tpm_fd = -1;
err_free_parameters:
g_free(tb->path);
tb->path = NULL;
g_free(tpm_pt->tpm_dev);
tpm_pt->tpm_dev = NULL;
return 1;
}
