hw/tpm/tpm_passthrough.c

   1 /*
   2  *  passthrough TPM driver
   3  *
   4  *  Copyright (c) 2010 - 2013 IBM Corporation
   5  *  Authors:
   6  *    Stefan Berger <stefanb@us.ibm.com>
   7  *
   8  *  Copyright (C) 2011 IAIK, Graz University of Technology
   9  *    Author: Andreas Niederl
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2 of the License, or (at your option) any later version.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, see <http://www.gnu.org/licenses/>
  23  */
  24
  25 #include <dirent.h>
  26
  27 #include "qemu-common.h"
  28 #include "qapi/error.h"
  29 #include "qemu/sockets.h"
  30 #include "sysemu/tpm_backend.h"
  31 #include "tpm_int.h"
  32 #include "hw/hw.h"
  33 #include "hw/i386/pc.h"
  34 #include "sysemu/tpm_backend_int.h"
  35 #include "tpm_tis.h"
  36 #include "tpm_util.h"
  37
  38 #define DEBUG_TPM 0
  39
  40 #define DPRINTF(fmt, ...) do { \
  41     if (DEBUG_TPM) { \
  42         fprintf(stderr, fmt, ## __VA_ARGS__); \
  43     } \
  44 } while (0);
  45
  46 #define TYPE_TPM_PASSTHROUGH "tpm-passthrough"
  47 #define TPM_PASSTHROUGH(obj) \
  48     OBJECT_CHECK(TPMPassthruState, (obj), TYPE_TPM_PASSTHROUGH)
  49
  50 static const TPMDriverOps tpm_passthrough_driver;
  51
  52 /* data structures */
  53 typedef struct TPMPassthruThreadParams {
  54     TPMState *tpm_state;
  55
  56     TPMRecvDataCB *recv_data_callback;
  57     TPMBackend *tb;
  58 } TPMPassthruThreadParams;
  59
  60 struct TPMPassthruState {
  61     TPMBackend parent;
  62
  63     TPMBackendThread tbt;
  64
  65     TPMPassthruThreadParams tpm_thread_params;
  66
  67     char *tpm_dev;
  68     int tpm_fd;
  69     bool tpm_executing;
  70     bool tpm_op_canceled;
  71     int cancel_fd;
  72     bool had_startup_error;
  73
  74     TPMVersion tpm_version;
  75 };
  76
  77 typedef struct TPMPassthruState TPMPassthruState;
  78
  79 #define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
  80
  81 /* functions */
  82
  83 static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
  84
  85 static int tpm_passthrough_unix_write(int fd, const uint8_t *buf, uint32_t len)
  86 {
  87     return send_all(fd, buf, len);
  88 }
  89
  90 static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
  91 {
  92     return recv_all(fd, buf, len, true);
  93 }
  94
  95 static uint32_t tpm_passthrough_get_size_from_buffer(const uint8_t *buf)
  96 {
  97     struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)buf;
  98
  99     return be32_to_cpu(resp->len);
 100 }
 101
 102 /*
 103  * Write an error message in the given output buffer.
 104  */
 105 static void tpm_write_fatal_error_response(uint8_t *out, uint32_t out_len)
 106 {
 107     if (out_len >= sizeof(struct tpm_resp_hdr)) {
 108         struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out;
 109
 110         resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND);
 111         resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr));
 112         resp->errcode = cpu_to_be32(TPM_FAIL);
 113     }
 114 }
 115
 116 static bool tpm_passthrough_is_selftest(const uint8_t *in, uint32_t in_len)
 117 {
 118     struct tpm_req_hdr *hdr = (struct tpm_req_hdr *)in;
 119
 120     if (in_len >= sizeof(*hdr)) {
 121         return (be32_to_cpu(hdr->ordinal) == TPM_ORD_ContinueSelfTest);
 122     }
 123
 124     return false;
 125 }
 126
 127 static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
 128                                         const uint8_t *in, uint32_t in_len,
 129                                         uint8_t *out, uint32_t out_len,
 130                                         bool *selftest_done)
 131 {
 132     int ret;
 133     bool is_selftest;
 134     const struct tpm_resp_hdr *hdr;
 135
 136     tpm_pt->tpm_op_canceled = false;
 137     tpm_pt->tpm_executing = true;
 138     *selftest_done = false;
 139
 140     is_selftest = tpm_passthrough_is_selftest(in, in_len);
 141
 142     ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len);
 143     if (ret != in_len) {
 144         if (!tpm_pt->tpm_op_canceled ||
 145             (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
 146             error_report("tpm_passthrough: error while transmitting data "
 147                          "to TPM: %s (%i)",
 148                          strerror(errno), errno);
 149         }
 150         goto err_exit;
 151     }
 152
 153     tpm_pt->tpm_executing = false;
 154
 155     ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
 156     if (ret < 0) {
 157         if (!tpm_pt->tpm_op_canceled ||
 158             (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
 159             error_report("tpm_passthrough: error while reading data from "
 160                          "TPM: %s (%i)",
 161                          strerror(errno), errno);
 162         }
 163     } else if (ret < sizeof(struct tpm_resp_hdr) ||
 164                tpm_passthrough_get_size_from_buffer(out) != ret) {
 165         ret = -1;
 166         error_report("tpm_passthrough: received invalid response "
 167                      "packet from TPM");
 168     }
 169
 170     if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) {
 171         hdr = (struct tpm_resp_hdr *)out;
 172         *selftest_done = (be32_to_cpu(hdr->errcode) == 0);
 173     }
 174
 175 err_exit:
 176     if (ret < 0) {
 177         tpm_write_fatal_error_response(out, out_len);
 178     }
 179
 180     tpm_pt->tpm_executing = false;
 181
 182     return ret;
 183 }
 184
 185 static int tpm_passthrough_unix_transfer(TPMPassthruState *tpm_pt,
 186                                          const TPMLocality *locty_data,
 187                                          bool *selftest_done)
 188 {
 189     return tpm_passthrough_unix_tx_bufs(tpm_pt,
 190                                         locty_data->w_buffer.buffer,
 191                                         locty_data->w_offset,
 192                                         locty_data->r_buffer.buffer,
 193                                         locty_data->r_buffer.size,
 194                                         selftest_done);
 195 }
 196
 197 static void tpm_passthrough_worker_thread(gpointer data,
 198                                           gpointer user_data)
 199 {
 200     TPMPassthruThreadParams *thr_parms = user_data;
 201     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(thr_parms->tb);
 202     TPMBackendCmd cmd = (TPMBackendCmd)data;
 203     bool selftest_done = false;
 204
 205     DPRINTF("tpm_passthrough: processing command type %d\n", cmd);
 206
 207     switch (cmd) {
 208     case TPM_BACKEND_CMD_PROCESS_CMD:
 209         tpm_passthrough_unix_transfer(tpm_pt,
 210                                       thr_parms->tpm_state->locty_data,
 211                                       &selftest_done);
 212
 213         thr_parms->recv_data_callback(thr_parms->tpm_state,
 214                                       thr_parms->tpm_state->locty_number,
 215                                       selftest_done);
 216         break;
 217     case TPM_BACKEND_CMD_INIT:
 218     case TPM_BACKEND_CMD_END:
 219     case TPM_BACKEND_CMD_TPM_RESET:
 220         /* nothing to do */
 221         break;
 222     }
 223 }
 224
 225 /*
 226  * Start the TPM (thread). If it had been started before, then terminate
 227  * and start it again.
 228  */
 229 static int tpm_passthrough_startup_tpm(TPMBackend *tb)
 230 {
 231     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 232
 233     /* terminate a running TPM */
 234     tpm_backend_thread_end(&tpm_pt->tbt);
 235
 236     tpm_backend_thread_create(&tpm_pt->tbt,
 237                               tpm_passthrough_worker_thread,
 238                               &tpm_pt->tpm_thread_params);
 239
 240     return 0;
 241 }
 242
 243 static void tpm_passthrough_reset(TPMBackend *tb)
 244 {
 245     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 246
 247     DPRINTF("tpm_passthrough: CALL TO TPM_RESET!\n");
 248
 249     tpm_passthrough_cancel_cmd(tb);
 250
 251     tpm_backend_thread_end(&tpm_pt->tbt);
 252
 253     tpm_pt->had_startup_error = false;
 254 }
 255
 256 static int tpm_passthrough_init(TPMBackend *tb, TPMState *s,
 257                                 TPMRecvDataCB *recv_data_cb)
 258 {
 259     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 260
 261     tpm_pt->tpm_thread_params.tpm_state = s;
 262     tpm_pt->tpm_thread_params.recv_data_callback = recv_data_cb;
 263     tpm_pt->tpm_thread_params.tb = tb;
 264
 265     return 0;
 266 }
 267
 268 static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
 269 {
 270     return false;
 271 }
 272
 273 static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
 274                                                       uint8_t locty)
 275 {
 276     /* only a TPM 2.0 will support this */
 277     return 0;
 278 }
 279
 280 static bool tpm_passthrough_get_startup_error(TPMBackend *tb)
 281 {
 282     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 283
 284     return tpm_pt->had_startup_error;
 285 }
 286
 287 static size_t tpm_passthrough_realloc_buffer(TPMSizedBuffer *sb)
 288 {
 289     size_t wanted_size = 4096; /* Linux tpm.c buffer size */
 290
 291     if (sb->size != wanted_size) {
 292         sb->buffer = g_realloc(sb->buffer, wanted_size);
 293         sb->size = wanted_size;
 294     }
 295     return sb->size;
 296 }
 297
 298 static void tpm_passthrough_deliver_request(TPMBackend *tb)
 299 {
 300     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 301
 302     tpm_backend_thread_deliver_request(&tpm_pt->tbt);
 303 }
 304
 305 static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
 306 {
 307     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 308     int n;
 309
 310     /*
 311      * As of Linux 3.7 the tpm_tis driver does not properly cancel
 312      * commands on all TPM manufacturers' TPMs.
 313      * Only cancel if we're busy so we don't cancel someone else's
 314      * command, e.g., a command executed on the host.
 315      */
 316     if (tpm_pt->tpm_executing) {
 317         if (tpm_pt->cancel_fd >= 0) {
 318             n = write(tpm_pt->cancel_fd, "-", 1);
 319             if (n != 1) {
 320                 error_report("Canceling TPM command failed: %s",
 321                              strerror(errno));
 322             } else {
 323                 tpm_pt->tpm_op_canceled = true;
 324             }
 325         } else {
 326             error_report("Cannot cancel TPM command due to missing "
 327                          "TPM sysfs cancel entry");
 328         }
 329     }
 330 }
 331
 332 static const char *tpm_passthrough_create_desc(void)
 333 {
 334     return "Passthrough TPM backend driver";
 335 }
 336
 337 static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
 338 {
 339     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 340
 341     return tpm_pt->tpm_version;
 342 }
 343
 344 /*
 345  * Unless path or file descriptor set has been provided by user,
 346  * determine the sysfs cancel file following kernel documentation
 347  * in Documentation/ABI/stable/sysfs-class-tpm.
 348  * From /dev/tpm0 create /sys/class/misc/tpm0/device/cancel
 349  */
 350 static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
 351 {
 352     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 353     int fd = -1;
 354     char *dev;
 355     char path[PATH_MAX];
 356
 357     if (tb->cancel_path) {
 358         fd = qemu_open(tb->cancel_path, O_WRONLY);
 359         if (fd < 0) {
 360             error_report("Could not open TPM cancel path : %s",
 361                          strerror(errno));
 362         }
 363         return fd;
 364     }
 365
 366     dev = strrchr(tpm_pt->tpm_dev, '/');
 367     if (dev) {
 368         dev++;
 369         if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel",
 370                      dev) < sizeof(path)) {
 371             fd = qemu_open(path, O_WRONLY);
 372             if (fd >= 0) {
 373                 tb->cancel_path = g_strdup(path);
 374             } else {
 375                 error_report("tpm_passthrough: Could not open TPM cancel "
 376                              "path %s : %s", path, strerror(errno));
 377             }
 378         }
 379     } else {
 380        error_report("tpm_passthrough: Bad TPM device path %s",
 381                     tpm_pt->tpm_dev);
 382     }
 383
 384     return fd;
 385 }
 386
 387 static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
 388 {
 389     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 390     const char *value;
 391
 392     value = qemu_opt_get(opts, "cancel-path");
 393     tb->cancel_path = g_strdup(value);
 394
 395     value = qemu_opt_get(opts, "path");
 396     if (!value) {
 397         value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
 398     }
 399
 400     tpm_pt->tpm_dev = g_strdup(value);
 401
 402     tb->path = g_strdup(tpm_pt->tpm_dev);
 403
 404     tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
 405     if (tpm_pt->tpm_fd < 0) {
 406         error_report("Cannot access TPM device using '%s': %s",
 407                      tpm_pt->tpm_dev, strerror(errno));
 408         goto err_free_parameters;
 409     }
 410
 411     if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
 412         error_report("'%s' is not a TPM device.",
 413                      tpm_pt->tpm_dev);
 414         goto err_close_tpmdev;
 415     }
 416
 417     return 0;
 418
 419  err_close_tpmdev:
 420     qemu_close(tpm_pt->tpm_fd);
 421     tpm_pt->tpm_fd = -1;
 422
 423  err_free_parameters:
 424     g_free(tb->path);
 425     tb->path = NULL;
 426
 427     g_free(tpm_pt->tpm_dev);
 428     tpm_pt->tpm_dev = NULL;
 429
 430     return 1;
 431 }
 432
 433 static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
 434 {
 435     Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
 436     TPMBackend *tb = TPM_BACKEND(obj);
 437     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 438
 439     tb->id = g_strdup(id);
 440     /* let frontend set the fe_model to proper value */
 441     tb->fe_model = -1;
 442
 443     tb->ops = &tpm_passthrough_driver;
 444
 445     if (tpm_passthrough_handle_device_opts(opts, tb)) {
 446         goto err_exit;
 447     }
 448
 449     tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb);
 450     if (tpm_pt->cancel_fd < 0) {
 451         goto err_exit;
 452     }
 453
 454     return tb;
 455
 456 err_exit:
 457     g_free(tb->id);
 458
 459     return NULL;
 460 }
 461
 462 static void tpm_passthrough_destroy(TPMBackend *tb)
 463 {
 464     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 465
 466     tpm_passthrough_cancel_cmd(tb);
 467
 468     tpm_backend_thread_end(&tpm_pt->tbt);
 469
 470     qemu_close(tpm_pt->tpm_fd);
 471     qemu_close(tpm_pt->cancel_fd);
 472
 473     g_free(tb->id);
 474     g_free(tb->path);
 475     g_free(tb->cancel_path);
 476     g_free(tpm_pt->tpm_dev);
 477 }
 478
 479 static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
 480     TPM_STANDARD_CMDLINE_OPTS,
 481     {
 482         .name = "cancel-path",
 483         .type = QEMU_OPT_STRING,
 484         .help = "Sysfs file entry for canceling TPM commands",
 485     },
 486     {
 487         .name = "path",
 488         .type = QEMU_OPT_STRING,
 489         .help = "Path to TPM device on the host",
 490     },
 491     { /* end of list */ },
 492 };
 493
 494 static const TPMDriverOps tpm_passthrough_driver = {
 495     .type                     = TPM_TYPE_PASSTHROUGH,
 496     .opts                     = tpm_passthrough_cmdline_opts,
 497     .desc                     = tpm_passthrough_create_desc,
 498     .create                   = tpm_passthrough_create,
 499     .destroy                  = tpm_passthrough_destroy,
 500     .init                     = tpm_passthrough_init,
 501     .startup_tpm              = tpm_passthrough_startup_tpm,
 502     .realloc_buffer           = tpm_passthrough_realloc_buffer,
 503     .reset                    = tpm_passthrough_reset,
 504     .had_startup_error        = tpm_passthrough_get_startup_error,
 505     .deliver_request          = tpm_passthrough_deliver_request,
 506     .cancel_cmd               = tpm_passthrough_cancel_cmd,
 507     .get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag,
 508     .reset_tpm_established_flag = tpm_passthrough_reset_tpm_established_flag,
 509     .get_tpm_version          = tpm_passthrough_get_tpm_version,
 510 };
 511
 512 static void tpm_passthrough_inst_init(Object *obj)
 513 {
 514 }
 515
 516 static void tpm_passthrough_inst_finalize(Object *obj)
 517 {
 518 }
 519
 520 static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
 521 {
 522     TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
 523
 524     tbc->ops = &tpm_passthrough_driver;
 525 }
 526
 527 static const TypeInfo tpm_passthrough_info = {
 528     .name = TYPE_TPM_PASSTHROUGH,
 529     .parent = TYPE_TPM_BACKEND,
 530     .instance_size = sizeof(TPMPassthruState),
 531     .class_init = tpm_passthrough_class_init,
 532     .instance_init = tpm_passthrough_inst_init,
 533     .instance_finalize = tpm_passthrough_inst_finalize,
 534 };
 535
 536 static void tpm_passthrough_register(void)
 537 {
 538     type_register_static(&tpm_passthrough_info);
 539     tpm_register_driver(&tpm_passthrough_driver);
 540 }
 541
 542 type_init(tpm_passthrough_register)