qemu/hw/tpm/tpm_passthrough.c

565 lines
16 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 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/sockets.h"
#include "sysemu/tpm_backend.h"
#include "tpm_int.h"
#include "hw/hw.h"
#include "hw/i386/pc.h"
#include "sysemu/tpm_backend_int.h"
#include "tpm_tis.h"
#include "tpm_util.h"
#define DEBUG_TPM 0
#define DPRINTF(fmt, ...) do { \
if (DEBUG_TPM) { \
fprintf(stderr, fmt, ## __VA_ARGS__); \
} \
} while (0);
#define TYPE_TPM_PASSTHROUGH "tpm-passthrough"
#define TPM_PASSTHROUGH(obj) \
OBJECT_CHECK(TPMPassthruState, (obj), TYPE_TPM_PASSTHROUGH)
static const TPMDriverOps tpm_passthrough_driver;
/* data structures */
typedef struct TPMPassthruThreadParams {
TPMState *tpm_state;
TPMRecvDataCB *recv_data_callback;
TPMBackend *tb;
} TPMPassthruThreadParams;
struct TPMPassthruState {
TPMBackend parent;
TPMBackendThread tbt;
TPMPassthruThreadParams tpm_thread_params;
char *tpm_dev;
int tpm_fd;
bool tpm_executing;
bool tpm_op_canceled;
int cancel_fd;
bool had_startup_error;
TPMVersion tpm_version;
};
typedef struct TPMPassthruState TPMPassthruState;
#define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
/* functions */
static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
static int tpm_passthrough_unix_write(int fd, const uint8_t *buf, uint32_t len)
{
int ret, remain;
remain = len;
while (remain > 0) {
ret = write(fd, buf, remain);
if (ret < 0) {
if (errno != EINTR && errno != EAGAIN) {
return -1;
}
} else if (ret == 0) {
break;
} else {
buf += ret;
remain -= ret;
}
}
return len - remain;
}
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 uint32_t tpm_passthrough_get_size_from_buffer(const uint8_t *buf)
{
struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)buf;
return be32_to_cpu(resp->len);
}
/*
* Write an error message in the given output buffer.
*/
static void tpm_write_fatal_error_response(uint8_t *out, uint32_t out_len)
{
if (out_len >= sizeof(struct tpm_resp_hdr)) {
struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out;
resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND);
resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr));
resp->errcode = cpu_to_be32(TPM_FAIL);
}
}
static bool tpm_passthrough_is_selftest(const uint8_t *in, uint32_t in_len)
{
struct tpm_req_hdr *hdr = (struct tpm_req_hdr *)in;
if (in_len >= sizeof(*hdr)) {
return (be32_to_cpu(hdr->ordinal) == TPM_ORD_ContinueSelfTest);
}
return false;
}
static int 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)
{
int ret;
bool is_selftest;
const struct tpm_resp_hdr *hdr;
tpm_pt->tpm_op_canceled = false;
tpm_pt->tpm_executing = true;
*selftest_done = false;
is_selftest = tpm_passthrough_is_selftest(in, in_len);
ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len);
if (ret != in_len) {
if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
error_report("tpm_passthrough: error while transmitting data "
"to TPM: %s (%i)",
strerror(errno), errno);
}
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_report("tpm_passthrough: error while reading data from "
"TPM: %s (%i)",
strerror(errno), errno);
}
} else if (ret < sizeof(struct tpm_resp_hdr) ||
tpm_passthrough_get_size_from_buffer(out) != ret) {
ret = -1;
error_report("tpm_passthrough: received invalid response "
"packet from TPM");
}
if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) {
hdr = (struct tpm_resp_hdr *)out;
*selftest_done = (be32_to_cpu(hdr->errcode) == 0);
}
err_exit:
if (ret < 0) {
tpm_write_fatal_error_response(out, out_len);
}
tpm_pt->tpm_executing = false;
return ret;
}
static int tpm_passthrough_unix_transfer(TPMPassthruState *tpm_pt,
const TPMLocality *locty_data,
bool *selftest_done)
{
return tpm_passthrough_unix_tx_bufs(tpm_pt,
locty_data->w_buffer.buffer,
locty_data->w_offset,
locty_data->r_buffer.buffer,
locty_data->r_buffer.size,
selftest_done);
}
static void tpm_passthrough_worker_thread(gpointer data,
gpointer user_data)
{
TPMPassthruThreadParams *thr_parms = user_data;
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(thr_parms->tb);
TPMBackendCmd cmd = (TPMBackendCmd)data;
bool selftest_done = false;
DPRINTF("tpm_passthrough: processing command type %d\n", cmd);
switch (cmd) {
case TPM_BACKEND_CMD_PROCESS_CMD:
tpm_passthrough_unix_transfer(tpm_pt,
thr_parms->tpm_state->locty_data,
&selftest_done);
thr_parms->recv_data_callback(thr_parms->tpm_state,
thr_parms->tpm_state->locty_number,
selftest_done);
break;
case TPM_BACKEND_CMD_INIT:
case TPM_BACKEND_CMD_END:
case TPM_BACKEND_CMD_TPM_RESET:
/* nothing to do */
break;
}
}
/*
* Start the TPM (thread). If it had been started before, then terminate
* and start it again.
*/
static int tpm_passthrough_startup_tpm(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
/* terminate a running TPM */
tpm_backend_thread_end(&tpm_pt->tbt);
tpm_backend_thread_create(&tpm_pt->tbt,
tpm_passthrough_worker_thread,
&tpm_pt->tpm_thread_params);
return 0;
}
static void tpm_passthrough_reset(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
DPRINTF("tpm_passthrough: CALL TO TPM_RESET!\n");
tpm_passthrough_cancel_cmd(tb);
tpm_backend_thread_end(&tpm_pt->tbt);
tpm_pt->had_startup_error = false;
}
static int tpm_passthrough_init(TPMBackend *tb, TPMState *s,
TPMRecvDataCB *recv_data_cb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
tpm_pt->tpm_thread_params.tpm_state = s;
tpm_pt->tpm_thread_params.recv_data_callback = recv_data_cb;
tpm_pt->tpm_thread_params.tb = tb;
return 0;
}
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 bool tpm_passthrough_get_startup_error(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
return tpm_pt->had_startup_error;
}
static size_t tpm_passthrough_realloc_buffer(TPMSizedBuffer *sb)
{
size_t wanted_size = 4096; /* Linux tpm.c buffer size */
if (sb->size != wanted_size) {
sb->buffer = g_realloc(sb->buffer, wanted_size);
sb->size = wanted_size;
}
return sb->size;
}
static void tpm_passthrough_deliver_request(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
tpm_backend_thread_deliver_request(&tpm_pt->tbt);
}
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) {
n = write(tpm_pt->cancel_fd, "-", 1);
if (n != 1) {
error_report("Canceling TPM command failed: %s",
strerror(errno));
} else {
tpm_pt->tpm_op_canceled = true;
}
} else {
error_report("Cannot cancel TPM command due to missing "
"TPM sysfs cancel entry");
}
}
}
static const char *tpm_passthrough_create_desc(void)
{
return "Passthrough TPM backend driver";
}
static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
return tpm_pt->tpm_version;
}
/*
* 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_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
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;
}
static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
{
Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
TPMBackend *tb = TPM_BACKEND(obj);
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
tb->id = g_strdup(id);
/* let frontend set the fe_model to proper value */
tb->fe_model = -1;
tb->ops = &tpm_passthrough_driver;
if (tpm_passthrough_handle_device_opts(opts, tb)) {
goto err_exit;
}
tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb);
if (tpm_pt->cancel_fd < 0) {
goto err_exit;
}
return tb;
err_exit:
g_free(tb->id);
return NULL;
}
static void tpm_passthrough_destroy(TPMBackend *tb)
{
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
tpm_passthrough_cancel_cmd(tb);
tpm_backend_thread_end(&tpm_pt->tbt);
qemu_close(tpm_pt->tpm_fd);
qemu_close(tpm_pt->cancel_fd);
g_free(tb->id);
g_free(tb->path);
g_free(tb->cancel_path);
g_free(tpm_pt->tpm_dev);
}
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 const TPMDriverOps tpm_passthrough_driver = {
.type = TPM_TYPE_PASSTHROUGH,
.opts = tpm_passthrough_cmdline_opts,
.desc = tpm_passthrough_create_desc,
.create = tpm_passthrough_create,
.destroy = tpm_passthrough_destroy,
.init = tpm_passthrough_init,
.startup_tpm = tpm_passthrough_startup_tpm,
.realloc_buffer = tpm_passthrough_realloc_buffer,
.reset = tpm_passthrough_reset,
.had_startup_error = tpm_passthrough_get_startup_error,
.deliver_request = tpm_passthrough_deliver_request,
.cancel_cmd = tpm_passthrough_cancel_cmd,
.get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag,
.reset_tpm_established_flag = tpm_passthrough_reset_tpm_established_flag,
.get_tpm_version = tpm_passthrough_get_tpm_version,
};
static void tpm_passthrough_inst_init(Object *obj)
{
}
static void tpm_passthrough_inst_finalize(Object *obj)
{
}
static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
{
TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
tbc->ops = &tpm_passthrough_driver;
}
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);
tpm_register_driver(&tpm_passthrough_driver);
}
type_init(tpm_passthrough_register)