qemu/hw/tpm/tpm_passthrough.c
Stefan Berger bb71623811 Move TPM passthrough specific command line options to backend structure
Move the TPM passthrough specific command line options to the passthrough
backend implementation and attach them to the backend's interface structure.

Add code to tpm.c for validating the TPM command line options.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Corey Bryan <coreyb@linux.vnet.ibm.com>
Message-id: 1366641699-21420-1-git-send-email-stefanb@linux.vnet.ibm.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-23 10:40:40 -05:00

553 lines
15 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 <dirent.h>
#include "qemu-common.h"
#include "qapi/error.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"
/* #define DEBUG_TPM */
#ifdef DEBUG_TPM
#define DPRINTF(fmt, ...) \
do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
do { } while (0)
#endif
#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;
};
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)
{
return send_all(fd, buf, len);
}
static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
{
return recv_all(fd, buf, len, true);
}
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 int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
const uint8_t *in, uint32_t in_len,
uint8_t *out, uint32_t out_len)
{
int ret;
tpm_pt->tpm_op_canceled = false;
tpm_pt->tpm_executing = true;
ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len);
if (ret != in_len) {
if (!tpm_pt->tpm_op_canceled ||
(tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
error_report("tpm_passthrough: error while transmitting data "
"to TPM: %s (%i)\n",
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 ||
(tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
error_report("tpm_passthrough: error while reading data from "
"TPM: %s (%i)\n",
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\n");
}
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)
{
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);
}
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;
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);
thr_parms->recv_data_callback(thr_parms->tpm_state,
thr_parms->tpm_state->locty_number);
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 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\n",
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";
}
/*
* 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");
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;
}
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,
};
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)