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 "qemu/osdep.h"
  26 #include "qemu-common.h"
  27 #include "qemu/error-report.h"
  28 #include "qemu/sockets.h"
  29 #include "sysemu/tpm_backend.h"
  30 #include "tpm_int.h"
  31 #include "hw/hw.h"
  32 #include "hw/i386/pc.h"
  33 #include "sysemu/tpm_backend_int.h"
  34 #include "tpm_tis.h"
  35 #include "tpm_util.h"
  36
  37 #define DEBUG_TPM 0
  38
  39 #define DPRINTF(fmt, ...) do { \
  40     if (DEBUG_TPM) { \
  41         fprintf(stderr, fmt, ## __VA_ARGS__); \
  42     } \
  43 } while (0);
  44
  45 #define TYPE_TPM_PASSTHROUGH "tpm-passthrough"
  46 #define TPM_PASSTHROUGH(obj) \
  47     OBJECT_CHECK(TPMPassthruState, (obj), TYPE_TPM_PASSTHROUGH)
  48
  49 static const TPMDriverOps tpm_passthrough_driver;
  50
  51 /* data structures */
  52 typedef struct TPMPassthruThreadParams {
  53     TPMState *tpm_state;
  54
  55     TPMRecvDataCB *recv_data_callback;
  56     TPMBackend *tb;
  57 } TPMPassthruThreadParams;
  58
  59 struct TPMPassthruState {
  60     TPMBackend parent;
  61
  62     TPMBackendThread tbt;
  63
  64     TPMPassthruThreadParams tpm_thread_params;
  65
  66     char *tpm_dev;
  67     int tpm_fd;
  68     bool tpm_executing;
  69     bool tpm_op_canceled;
  70     int cancel_fd;
  71     bool had_startup_error;
  72
  73     TPMVersion tpm_version;
  74 };
  75
  76 typedef struct TPMPassthruState TPMPassthruState;
  77
  78 #define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
  79
  80 /* functions */
  81
  82 static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
  83
  84 static int tpm_passthrough_unix_write(int fd, const uint8_t *buf, uint32_t len)
  85 {
  86     int ret, remain;
  87
  88     remain = len;
  89     while (remain > 0) {
  90         ret = write(fd, buf, remain);
  91         if (ret < 0) {
  92             if (errno != EINTR && errno != EAGAIN) {
  93                 return -1;
  94             }
  95         } else if (ret == 0) {
  96             break;
  97         } else {
  98             buf += ret;
  99             remain -= ret;
 100         }
 101     }
 102     return len - remain;
 103 }
 104
 105 static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
 106 {
 107     int ret;
 108  reread:
 109     ret = read(fd, buf, len);
 110     if (ret < 0) {
 111         if (errno != EINTR && errno != EAGAIN) {
 112             return -1;
 113         }
 114         goto reread;
 115     }
 116     return ret;
 117 }
 118
 119 static uint32_t tpm_passthrough_get_size_from_buffer(const uint8_t *buf)
 120 {
 121     struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)buf;
 122
 123     return be32_to_cpu(resp->len);
 124 }
 125
 126 /*
 127  * Write an error message in the given output buffer.
 128  */
 129 static void tpm_write_fatal_error_response(uint8_t *out, uint32_t out_len)
 130 {
 131     if (out_len >= sizeof(struct tpm_resp_hdr)) {
 132         struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out;
 133
 134         resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND);
 135         resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr));
 136         resp->errcode = cpu_to_be32(TPM_FAIL);
 137     }
 138 }
 139
 140 static bool tpm_passthrough_is_selftest(const uint8_t *in, uint32_t in_len)
 141 {
 142     struct tpm_req_hdr *hdr = (struct tpm_req_hdr *)in;
 143
 144     if (in_len >= sizeof(*hdr)) {
 145         return (be32_to_cpu(hdr->ordinal) == TPM_ORD_ContinueSelfTest);
 146     }
 147
 148     return false;
 149 }
 150
 151 static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
 152                                         const uint8_t *in, uint32_t in_len,
 153                                         uint8_t *out, uint32_t out_len,
 154                                         bool *selftest_done)
 155 {
 156     int ret;
 157     bool is_selftest;
 158     const struct tpm_resp_hdr *hdr;
 159
 160     tpm_pt->tpm_op_canceled = false;
 161     tpm_pt->tpm_executing = true;
 162     *selftest_done = false;
 163
 164     is_selftest = tpm_passthrough_is_selftest(in, in_len);
 165
 166     ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len);
 167     if (ret != in_len) {
 168         if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
 169             error_report("tpm_passthrough: error while transmitting data "
 170                          "to TPM: %s (%i)",
 171                          strerror(errno), errno);
 172         }
 173         goto err_exit;
 174     }
 175
 176     tpm_pt->tpm_executing = false;
 177
 178     ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
 179     if (ret < 0) {
 180         if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
 181             error_report("tpm_passthrough: error while reading data from "
 182                          "TPM: %s (%i)",
 183                          strerror(errno), errno);
 184         }
 185     } else if (ret < sizeof(struct tpm_resp_hdr) ||
 186                tpm_passthrough_get_size_from_buffer(out) != ret) {
 187         ret = -1;
 188         error_report("tpm_passthrough: received invalid response "
 189                      "packet from TPM");
 190     }
 191
 192     if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) {
 193         hdr = (struct tpm_resp_hdr *)out;
 194         *selftest_done = (be32_to_cpu(hdr->errcode) == 0);
 195     }
 196
 197 err_exit:
 198     if (ret < 0) {
 199         tpm_write_fatal_error_response(out, out_len);
 200     }
 201
 202     tpm_pt->tpm_executing = false;
 203
 204     return ret;
 205 }
 206
 207 static int tpm_passthrough_unix_transfer(TPMPassthruState *tpm_pt,
 208                                          const TPMLocality *locty_data,
 209                                          bool *selftest_done)
 210 {
 211     return tpm_passthrough_unix_tx_bufs(tpm_pt,
 212                                         locty_data->w_buffer.buffer,
 213                                         locty_data->w_offset,
 214                                         locty_data->r_buffer.buffer,
 215                                         locty_data->r_buffer.size,
 216                                         selftest_done);
 217 }
 218
 219 static void tpm_passthrough_worker_thread(gpointer data,
 220                                           gpointer user_data)
 221 {
 222     TPMPassthruThreadParams *thr_parms = user_data;
 223     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(thr_parms->tb);
 224     TPMBackendCmd cmd = (TPMBackendCmd)data;
 225     bool selftest_done = false;
 226
 227     DPRINTF("tpm_passthrough: processing command type %d\n", cmd);
 228
 229     switch (cmd) {
 230     case TPM_BACKEND_CMD_PROCESS_CMD:
 231         tpm_passthrough_unix_transfer(tpm_pt,
 232                                       thr_parms->tpm_state->locty_data,
 233                                       &selftest_done);
 234
 235         thr_parms->recv_data_callback(thr_parms->tpm_state,
 236                                       thr_parms->tpm_state->locty_number,
 237                                       selftest_done);
 238         break;
 239     case TPM_BACKEND_CMD_INIT:
 240     case TPM_BACKEND_CMD_END:
 241     case TPM_BACKEND_CMD_TPM_RESET:
 242         /* nothing to do */
 243         break;
 244     }
 245 }
 246
 247 /*
 248  * Start the TPM (thread). If it had been started before, then terminate
 249  * and start it again.
 250  */
 251 static int tpm_passthrough_startup_tpm(TPMBackend *tb)
 252 {
 253     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 254
 255     /* terminate a running TPM */
 256     tpm_backend_thread_end(&tpm_pt->tbt);
 257
 258     tpm_backend_thread_create(&tpm_pt->tbt,
 259                               tpm_passthrough_worker_thread,
 260                               &tpm_pt->tpm_thread_params);
 261
 262     return 0;
 263 }
 264
 265 static void tpm_passthrough_reset(TPMBackend *tb)
 266 {
 267     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 268
 269     DPRINTF("tpm_passthrough: CALL TO TPM_RESET!\n");
 270
 271     tpm_passthrough_cancel_cmd(tb);
 272
 273     tpm_backend_thread_end(&tpm_pt->tbt);
 274
 275     tpm_pt->had_startup_error = false;
 276 }
 277
 278 static int tpm_passthrough_init(TPMBackend *tb, TPMState *s,
 279                                 TPMRecvDataCB *recv_data_cb)
 280 {
 281     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 282
 283     tpm_pt->tpm_thread_params.tpm_state = s;
 284     tpm_pt->tpm_thread_params.recv_data_callback = recv_data_cb;
 285     tpm_pt->tpm_thread_params.tb = tb;
 286
 287     return 0;
 288 }
 289
 290 static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
 291 {
 292     return false;
 293 }
 294
 295 static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
 296                                                       uint8_t locty)
 297 {
 298     /* only a TPM 2.0 will support this */
 299     return 0;
 300 }
 301
 302 static bool tpm_passthrough_get_startup_error(TPMBackend *tb)
 303 {
 304     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 305
 306     return tpm_pt->had_startup_error;
 307 }
 308
 309 static size_t tpm_passthrough_realloc_buffer(TPMSizedBuffer *sb)
 310 {
 311     size_t wanted_size = 4096; /* Linux tpm.c buffer size */
 312
 313     if (sb->size != wanted_size) {
 314         sb->buffer = g_realloc(sb->buffer, wanted_size);
 315         sb->size = wanted_size;
 316     }
 317     return sb->size;
 318 }
 319
 320 static void tpm_passthrough_deliver_request(TPMBackend *tb)
 321 {
 322     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 323
 324     tpm_backend_thread_deliver_request(&tpm_pt->tbt);
 325 }
 326
 327 static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
 328 {
 329     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 330     int n;
 331
 332     /*
 333      * As of Linux 3.7 the tpm_tis driver does not properly cancel
 334      * commands on all TPM manufacturers' TPMs.
 335      * Only cancel if we're busy so we don't cancel someone else's
 336      * command, e.g., a command executed on the host.
 337      */
 338     if (tpm_pt->tpm_executing) {
 339         if (tpm_pt->cancel_fd >= 0) {
 340             n = write(tpm_pt->cancel_fd, "-", 1);
 341             if (n != 1) {
 342                 error_report("Canceling TPM command failed: %s",
 343                              strerror(errno));
 344             } else {
 345                 tpm_pt->tpm_op_canceled = true;
 346             }
 347         } else {
 348             error_report("Cannot cancel TPM command due to missing "
 349                          "TPM sysfs cancel entry");
 350         }
 351     }
 352 }
 353
 354 static const char *tpm_passthrough_create_desc(void)
 355 {
 356     return "Passthrough TPM backend driver";
 357 }
 358
 359 static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
 360 {
 361     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 362
 363     return tpm_pt->tpm_version;
 364 }
 365
 366 /*
 367  * Unless path or file descriptor set has been provided by user,
 368  * determine the sysfs cancel file following kernel documentation
 369  * in Documentation/ABI/stable/sysfs-class-tpm.
 370  * From /dev/tpm0 create /sys/class/misc/tpm0/device/cancel
 371  */
 372 static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
 373 {
 374     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 375     int fd = -1;
 376     char *dev;
 377     char path[PATH_MAX];
 378
 379     if (tb->cancel_path) {
 380         fd = qemu_open(tb->cancel_path, O_WRONLY);
 381         if (fd < 0) {
 382             error_report("Could not open TPM cancel path : %s",
 383                          strerror(errno));
 384         }
 385         return fd;
 386     }
 387
 388     dev = strrchr(tpm_pt->tpm_dev, '/');
 389     if (dev) {
 390         dev++;
 391         if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel",
 392                      dev) < sizeof(path)) {
 393             fd = qemu_open(path, O_WRONLY);
 394             if (fd >= 0) {
 395                 tb->cancel_path = g_strdup(path);
 396             } else {
 397                 error_report("tpm_passthrough: Could not open TPM cancel "
 398                              "path %s : %s", path, strerror(errno));
 399             }
 400         }
 401     } else {
 402        error_report("tpm_passthrough: Bad TPM device path %s",
 403                     tpm_pt->tpm_dev);
 404     }
 405
 406     return fd;
 407 }
 408
 409 static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
 410 {
 411     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 412     const char *value;
 413
 414     value = qemu_opt_get(opts, "cancel-path");
 415     tb->cancel_path = g_strdup(value);
 416
 417     value = qemu_opt_get(opts, "path");
 418     if (!value) {
 419         value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
 420     }
 421
 422     tpm_pt->tpm_dev = g_strdup(value);
 423
 424     tb->path = g_strdup(tpm_pt->tpm_dev);
 425
 426     tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
 427     if (tpm_pt->tpm_fd < 0) {
 428         error_report("Cannot access TPM device using '%s': %s",
 429                      tpm_pt->tpm_dev, strerror(errno));
 430         goto err_free_parameters;
 431     }
 432
 433     if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
 434         error_report("'%s' is not a TPM device.",
 435                      tpm_pt->tpm_dev);
 436         goto err_close_tpmdev;
 437     }
 438
 439     return 0;
 440
 441  err_close_tpmdev:
 442     qemu_close(tpm_pt->tpm_fd);
 443     tpm_pt->tpm_fd = -1;
 444
 445  err_free_parameters:
 446     g_free(tb->path);
 447     tb->path = NULL;
 448
 449     g_free(tpm_pt->tpm_dev);
 450     tpm_pt->tpm_dev = NULL;
 451
 452     return 1;
 453 }
 454
 455 static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
 456 {
 457     Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
 458     TPMBackend *tb = TPM_BACKEND(obj);
 459     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 460
 461     tb->id = g_strdup(id);
 462     /* let frontend set the fe_model to proper value */
 463     tb->fe_model = -1;
 464
 465     tb->ops = &tpm_passthrough_driver;
 466
 467     if (tpm_passthrough_handle_device_opts(opts, tb)) {
 468         goto err_exit;
 469     }
 470
 471     tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb);
 472     if (tpm_pt->cancel_fd < 0) {
 473         goto err_exit;
 474     }
 475
 476     return tb;
 477
 478 err_exit:
 479     g_free(tb->id);
 480
 481     return NULL;
 482 }
 483
 484 static void tpm_passthrough_destroy(TPMBackend *tb)
 485 {
 486     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 487
 488     tpm_passthrough_cancel_cmd(tb);
 489
 490     tpm_backend_thread_end(&tpm_pt->tbt);
 491
 492     qemu_close(tpm_pt->tpm_fd);
 493     qemu_close(tpm_pt->cancel_fd);
 494
 495     g_free(tb->id);
 496     g_free(tb->path);
 497     g_free(tb->cancel_path);
 498     g_free(tpm_pt->tpm_dev);
 499 }
 500
 501 static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
 502     TPM_STANDARD_CMDLINE_OPTS,
 503     {
 504         .name = "cancel-path",
 505         .type = QEMU_OPT_STRING,
 506         .help = "Sysfs file entry for canceling TPM commands",
 507     },
 508     {
 509         .name = "path",
 510         .type = QEMU_OPT_STRING,
 511         .help = "Path to TPM device on the host",
 512     },
 513     { /* end of list */ },
 514 };
 515
 516 static const TPMDriverOps tpm_passthrough_driver = {
 517     .type                     = TPM_TYPE_PASSTHROUGH,
 518     .opts                     = tpm_passthrough_cmdline_opts,
 519     .desc                     = tpm_passthrough_create_desc,
 520     .create                   = tpm_passthrough_create,
 521     .destroy                  = tpm_passthrough_destroy,
 522     .init                     = tpm_passthrough_init,
 523     .startup_tpm              = tpm_passthrough_startup_tpm,
 524     .realloc_buffer           = tpm_passthrough_realloc_buffer,
 525     .reset                    = tpm_passthrough_reset,
 526     .had_startup_error        = tpm_passthrough_get_startup_error,
 527     .deliver_request          = tpm_passthrough_deliver_request,
 528     .cancel_cmd               = tpm_passthrough_cancel_cmd,
 529     .get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag,
 530     .reset_tpm_established_flag = tpm_passthrough_reset_tpm_established_flag,
 531     .get_tpm_version          = tpm_passthrough_get_tpm_version,
 532 };
 533
 534 static void tpm_passthrough_inst_init(Object *obj)
 535 {
 536 }
 537
 538 static void tpm_passthrough_inst_finalize(Object *obj)
 539 {
 540 }
 541
 542 static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
 543 {
 544     TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
 545
 546     tbc->ops = &tpm_passthrough_driver;
 547 }
 548
 549 static const TypeInfo tpm_passthrough_info = {
 550     .name = TYPE_TPM_PASSTHROUGH,
 551     .parent = TYPE_TPM_BACKEND,
 552     .instance_size = sizeof(TPMPassthruState),
 553     .class_init = tpm_passthrough_class_init,
 554     .instance_init = tpm_passthrough_inst_init,
 555     .instance_finalize = tpm_passthrough_inst_finalize,
 556 };
 557
 558 static void tpm_passthrough_register(void)
 559 {
 560     type_register_static(&tpm_passthrough_info);
 561     tpm_register_driver(&tpm_passthrough_driver);
 562 }
 563
 564 type_init(tpm_passthrough_register)