qemu/backends/tpm/tpm_passthrough.c
Chetan Pant eac2fce957 tpm: Fix Lesser GPL version number
There is no "version 2" of the "Lesser" General Public License.
It is either "GPL version 2.0" or "Lesser GPL version 2.1".
This patch replaces all occurrences of "Lesser GPL version 2" with
"Lesser GPL version 2.1" in comment section.

Signed-off-by: Chetan Pant <chetan4windows@gmail.com>
Message-Id: <20201023123516.19843-1-chetan4windows@gmail.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-11-15 16:44:18 +01:00

405 lines
12 KiB
C

/*
* passthrough TPM driver
*
* Copyright (c) 2010 - 2013 IBM Corporation
* Authors:
* Stefan Berger <stefanb@us.ibm.com>
*
* Copyright (C) 2011 IAIK, Graz University of Technology
* Author: Andreas Niederl
*
* 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 2.1 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 "qemu-common.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
#include "qemu/sockets.h"
#include "sysemu/tpm_backend.h"
#include "sysemu/tpm_util.h"
#include "tpm_int.h"
#include "qapi/clone-visitor.h"
#include "qapi/qapi-visit-tpm.h"
#include "trace.h"
#include "qom/object.h"
#define TYPE_TPM_PASSTHROUGH "tpm-passthrough"
OBJECT_DECLARE_SIMPLE_TYPE(TPMPassthruState, TPM_PASSTHROUGH)
/* data structures */
struct TPMPassthruState {
TPMBackend parent;
TPMPassthroughOptions *options;
const char *tpm_dev;
int tpm_fd;
bool tpm_executing;
bool tpm_op_canceled;
int cancel_fd;
TPMVersion tpm_version;
size_t tpm_buffersize;
};
#define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
/* functions */
static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
{
int ret;
reread:
ret = read(fd, buf, len);
if (ret < 0) {
if (errno != EINTR && errno != EAGAIN) {
return -1;
}
goto reread;
}
return ret;
}
static void tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
const uint8_t *in, uint32_t in_len,
uint8_t *out, uint32_t out_len,
bool *selftest_done, Error **errp)
{
ssize_t ret;
bool is_selftest;
/* FIXME: protect shared variables or use other sync mechanism */
tpm_pt->tpm_op_canceled = false;
tpm_pt->tpm_executing = true;
*selftest_done = false;
is_selftest = tpm_util_is_selftest(in, in_len);
ret = qemu_write_full(tpm_pt->tpm_fd, in, in_len);
if (ret != in_len) {
if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
error_setg_errno(errp, errno, "tpm_passthrough: error while "
"transmitting data to TPM");
}
goto err_exit;
}
tpm_pt->tpm_executing = false;
ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
if (ret < 0) {
if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
error_setg_errno(errp, errno, "tpm_passthrough: error while "
"reading data from TPM");
}
} else if (ret < sizeof(struct tpm_resp_hdr) ||
tpm_cmd_get_size(out) != ret) {
ret = -1;
error_setg_errno(errp, errno, "tpm_passthrough: received invalid "
"response packet from TPM");
}
if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) {
*selftest_done = tpm_cmd_get_errcode(out) == 0;
}
err_exit:
if (ret < 0) {
tpm_util_write_fatal_error_response(out, out_len);
}
tpm_pt->tpm_executing = false;
}
static void tpm_passthrough_handle_request(TPMBackend *tb, TPMBackendCmd *cmd,
Error **errp)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
trace_tpm_passthrough_handle_request(cmd);
tpm_passthrough_unix_tx_bufs(tpm_pt, cmd->in, cmd->in_len,
cmd->out, cmd->out_len, &cmd->selftest_done,
errp);
}
static void tpm_passthrough_reset(TPMBackend *tb)
{
trace_tpm_passthrough_reset();
tpm_passthrough_cancel_cmd(tb);
}
static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
{
return false;
}
static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
uint8_t locty)
{
/* only a TPM 2.0 will support this */
return 0;
}
static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
int n;
/*
* As of Linux 3.7 the tpm_tis driver does not properly cancel
* commands on all TPM manufacturers' TPMs.
* Only cancel if we're busy so we don't cancel someone else's
* command, e.g., a command executed on the host.
*/
if (tpm_pt->tpm_executing) {
if (tpm_pt->cancel_fd >= 0) {
tpm_pt->tpm_op_canceled = true;
n = write(tpm_pt->cancel_fd, "-", 1);
if (n != 1) {
error_report("Canceling TPM command failed: %s",
strerror(errno));
}
} else {
error_report("Cannot cancel TPM command due to missing "
"TPM sysfs cancel entry");
}
}
}
static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
return tpm_pt->tpm_version;
}
static size_t tpm_passthrough_get_buffer_size(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
int ret;
ret = tpm_util_get_buffer_size(tpm_pt->tpm_fd, tpm_pt->tpm_version,
&tpm_pt->tpm_buffersize);
if (ret < 0) {
tpm_pt->tpm_buffersize = 4096;
}
return tpm_pt->tpm_buffersize;
}
/*
* 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/tpm/tpm0/device/cancel
* before 4.0: /sys/class/misc/tpm0/device/cancel
*/
static int tpm_passthrough_open_sysfs_cancel(TPMPassthruState *tpm_pt)
{
int fd = -1;
char *dev;
char path[PATH_MAX];
if (tpm_pt->options->cancel_path) {
fd = qemu_open_old(tpm_pt->options->cancel_path, O_WRONLY);
if (fd < 0) {
error_report("tpm_passthrough: Could not open TPM cancel path: %s",
strerror(errno));
}
return fd;
}
dev = strrchr(tpm_pt->tpm_dev, '/');
if (!dev) {
error_report("tpm_passthrough: Bad TPM device path %s",
tpm_pt->tpm_dev);
return -1;
}
dev++;
if (snprintf(path, sizeof(path), "/sys/class/tpm/%s/device/cancel",
dev) < sizeof(path)) {
fd = qemu_open_old(path, O_WRONLY);
if (fd < 0) {
if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel",
dev) < sizeof(path)) {
fd = qemu_open_old(path, O_WRONLY);
}
}
}
if (fd < 0) {
error_report("tpm_passthrough: Could not guess TPM cancel path");
} else {
tpm_pt->options->cancel_path = g_strdup(path);
}
return fd;
}
static int
tpm_passthrough_handle_device_opts(TPMPassthruState *tpm_pt, QemuOpts *opts)
{
const char *value;
value = qemu_opt_get(opts, "cancel-path");
if (value) {
tpm_pt->options->cancel_path = g_strdup(value);
tpm_pt->options->has_cancel_path = true;
}
value = qemu_opt_get(opts, "path");
if (value) {
tpm_pt->options->has_path = true;
tpm_pt->options->path = g_strdup(value);
}
tpm_pt->tpm_dev = value ? value : TPM_PASSTHROUGH_DEFAULT_DEVICE;
tpm_pt->tpm_fd = qemu_open_old(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));
return -1;
}
if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
error_report("'%s' is not a TPM device.",
tpm_pt->tpm_dev);
return -1;
}
tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tpm_pt);
if (tpm_pt->cancel_fd < 0) {
return -1;
}
return 0;
}
static TPMBackend *tpm_passthrough_create(QemuOpts *opts)
{
Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
if (tpm_passthrough_handle_device_opts(TPM_PASSTHROUGH(obj), opts)) {
object_unref(obj);
return NULL;
}
return TPM_BACKEND(obj);
}
static int tpm_passthrough_startup_tpm(TPMBackend *tb, size_t buffersize)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
if (buffersize && buffersize < tpm_pt->tpm_buffersize) {
error_report("Requested buffer size of %zu is smaller than host TPM's "
"fixed buffer size of %zu",
buffersize, tpm_pt->tpm_buffersize);
return -1;
}
return 0;
}
static TpmTypeOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb)
{
TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
options->u.passthrough.data = QAPI_CLONE(TPMPassthroughOptions,
TPM_PASSTHROUGH(tb)->options);
return options;
}
static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
TPM_STANDARD_CMDLINE_OPTS,
{
.name = "cancel-path",
.type = QEMU_OPT_STRING,
.help = "Sysfs file entry for canceling TPM commands",
},
{
.name = "path",
.type = QEMU_OPT_STRING,
.help = "Path to TPM device on the host",
},
{ /* end of list */ },
};
static void tpm_passthrough_inst_init(Object *obj)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
tpm_pt->options = g_new0(TPMPassthroughOptions, 1);
tpm_pt->tpm_fd = -1;
tpm_pt->cancel_fd = -1;
}
static void tpm_passthrough_inst_finalize(Object *obj)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
tpm_passthrough_cancel_cmd(TPM_BACKEND(obj));
if (tpm_pt->tpm_fd >= 0) {
qemu_close(tpm_pt->tpm_fd);
}
if (tpm_pt->cancel_fd >= 0) {
qemu_close(tpm_pt->cancel_fd);
}
qapi_free_TPMPassthroughOptions(tpm_pt->options);
}
static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
{
TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
tbc->type = TPM_TYPE_PASSTHROUGH;
tbc->opts = tpm_passthrough_cmdline_opts;
tbc->desc = "Passthrough TPM backend driver";
tbc->create = tpm_passthrough_create;
tbc->startup_tpm = tpm_passthrough_startup_tpm;
tbc->reset = tpm_passthrough_reset;
tbc->cancel_cmd = tpm_passthrough_cancel_cmd;
tbc->get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag;
tbc->reset_tpm_established_flag =
tpm_passthrough_reset_tpm_established_flag;
tbc->get_tpm_version = tpm_passthrough_get_tpm_version;
tbc->get_buffer_size = tpm_passthrough_get_buffer_size;
tbc->get_tpm_options = tpm_passthrough_get_tpm_options;
tbc->handle_request = tpm_passthrough_handle_request;
}
static const TypeInfo tpm_passthrough_info = {
.name = TYPE_TPM_PASSTHROUGH,
.parent = TYPE_TPM_BACKEND,
.instance_size = sizeof(TPMPassthruState),
.class_init = tpm_passthrough_class_init,
.instance_init = tpm_passthrough_inst_init,
.instance_finalize = tpm_passthrough_inst_finalize,
};
static void tpm_passthrough_register(void)
{
type_register_static(&tpm_passthrough_info);
}
type_init(tpm_passthrough_register)