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-common.h"
  26 #include "qapi/error.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 (len > 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 ||
 169             (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
 170             error_report("tpm_passthrough: error while transmitting data "
 171                          "to TPM: %s (%i)",
 172                          strerror(errno), errno);
 173         }
 174         goto err_exit;
 175     }
 176
 177     tpm_pt->tpm_executing = false;
 178
 179     ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
 180     if (ret < 0) {
 181         if (!tpm_pt->tpm_op_canceled ||
 182             (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
 183             error_report("tpm_passthrough: error while reading data from "
 184                          "TPM: %s (%i)",
 185                          strerror(errno), errno);
 186         }
 187     } else if (ret < sizeof(struct tpm_resp_hdr) ||
 188                tpm_passthrough_get_size_from_buffer(out) != ret) {
 189         ret = -1;
 190         error_report("tpm_passthrough: received invalid response "
 191                      "packet from TPM");
 192     }
 193
 194     if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) {
 195         hdr = (struct tpm_resp_hdr *)out;
 196         *selftest_done = (be32_to_cpu(hdr->errcode) == 0);
 197     }
 198
 199 err_exit:
 200     if (ret < 0) {
 201         tpm_write_fatal_error_response(out, out_len);
 202     }
 203
 204     tpm_pt->tpm_executing = false;
 205
 206     return ret;
 207 }
 208
 209 static int tpm_passthrough_unix_transfer(TPMPassthruState *tpm_pt,
 210                                          const TPMLocality *locty_data,
 211                                          bool *selftest_done)
 212 {
 213     return tpm_passthrough_unix_tx_bufs(tpm_pt,
 214                                         locty_data->w_buffer.buffer,
 215                                         locty_data->w_offset,
 216                                         locty_data->r_buffer.buffer,
 217                                         locty_data->r_buffer.size,
 218                                         selftest_done);
 219 }
 220
 221 static void tpm_passthrough_worker_thread(gpointer data,
 222                                           gpointer user_data)
 223 {
 224     TPMPassthruThreadParams *thr_parms = user_data;
 225     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(thr_parms->tb);
 226     TPMBackendCmd cmd = (TPMBackendCmd)data;
 227     bool selftest_done = false;
 228
 229     DPRINTF("tpm_passthrough: processing command type %d\n", cmd);
 230
 231     switch (cmd) {
 232     case TPM_BACKEND_CMD_PROCESS_CMD:
 233         tpm_passthrough_unix_transfer(tpm_pt,
 234                                       thr_parms->tpm_state->locty_data,
 235                                       &selftest_done);
 236
 237         thr_parms->recv_data_callback(thr_parms->tpm_state,
 238                                       thr_parms->tpm_state->locty_number,
 239                                       selftest_done);
 240         break;
 241     case TPM_BACKEND_CMD_INIT:
 242     case TPM_BACKEND_CMD_END:
 243     case TPM_BACKEND_CMD_TPM_RESET:
 244         /* nothing to do */
 245         break;
 246     }
 247 }
 248
 249 /*
 250  * Start the TPM (thread). If it had been started before, then terminate
 251  * and start it again.
 252  */
 253 static int tpm_passthrough_startup_tpm(TPMBackend *tb)
 254 {
 255     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 256
 257     /* terminate a running TPM */
 258     tpm_backend_thread_end(&tpm_pt->tbt);
 259
 260     tpm_backend_thread_create(&tpm_pt->tbt,
 261                               tpm_passthrough_worker_thread,
 262                               &tpm_pt->tpm_thread_params);
 263
 264     return 0;
 265 }
 266
 267 static void tpm_passthrough_reset(TPMBackend *tb)
 268 {
 269     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 270
 271     DPRINTF("tpm_passthrough: CALL TO TPM_RESET!\n");
 272
 273     tpm_passthrough_cancel_cmd(tb);
 274
 275     tpm_backend_thread_end(&tpm_pt->tbt);
 276
 277     tpm_pt->had_startup_error = false;
 278 }
 279
 280 static int tpm_passthrough_init(TPMBackend *tb, TPMState *s,
 281                                 TPMRecvDataCB *recv_data_cb)
 282 {
 283     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 284
 285     tpm_pt->tpm_thread_params.tpm_state = s;
 286     tpm_pt->tpm_thread_params.recv_data_callback = recv_data_cb;
 287     tpm_pt->tpm_thread_params.tb = tb;
 288
 289     return 0;
 290 }
 291
 292 static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
 293 {
 294     return false;
 295 }
 296
 297 static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
 298                                                       uint8_t locty)
 299 {
 300     /* only a TPM 2.0 will support this */
 301     return 0;
 302 }
 303
 304 static bool tpm_passthrough_get_startup_error(TPMBackend *tb)
 305 {
 306     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 307
 308     return tpm_pt->had_startup_error;
 309 }
 310
 311 static size_t tpm_passthrough_realloc_buffer(TPMSizedBuffer *sb)
 312 {
 313     size_t wanted_size = 4096; /* Linux tpm.c buffer size */
 314
 315     if (sb->size != wanted_size) {
 316         sb->buffer = g_realloc(sb->buffer, wanted_size);
 317         sb->size = wanted_size;
 318     }
 319     return sb->size;
 320 }
 321
 322 static void tpm_passthrough_deliver_request(TPMBackend *tb)
 323 {
 324     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 325
 326     tpm_backend_thread_deliver_request(&tpm_pt->tbt);
 327 }
 328
 329 static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
 330 {
 331     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 332     int n;
 333
 334     /*
 335      * As of Linux 3.7 the tpm_tis driver does not properly cancel
 336      * commands on all TPM manufacturers' TPMs.
 337      * Only cancel if we're busy so we don't cancel someone else's
 338      * command, e.g., a command executed on the host.
 339      */
 340     if (tpm_pt->tpm_executing) {
 341         if (tpm_pt->cancel_fd >= 0) {
 342             n = write(tpm_pt->cancel_fd, "-", 1);
 343             if (n != 1) {
 344                 error_report("Canceling TPM command failed: %s",
 345                              strerror(errno));
 346             } else {
 347                 tpm_pt->tpm_op_canceled = true;
 348             }
 349         } else {
 350             error_report("Cannot cancel TPM command due to missing "
 351                          "TPM sysfs cancel entry");
 352         }
 353     }
 354 }
 355
 356 static const char *tpm_passthrough_create_desc(void)
 357 {
 358     return "Passthrough TPM backend driver";
 359 }
 360
 361 static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
 362 {
 363     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 364
 365     return tpm_pt->tpm_version;
 366 }
 367
 368 /*
 369  * Unless path or file descriptor set has been provided by user,
 370  * determine the sysfs cancel file following kernel documentation
 371  * in Documentation/ABI/stable/sysfs-class-tpm.
 372  * From /dev/tpm0 create /sys/class/misc/tpm0/device/cancel
 373  */
 374 static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
 375 {
 376     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 377     int fd = -1;
 378     char *dev;
 379     char path[PATH_MAX];
 380
 381     if (tb->cancel_path) {
 382         fd = qemu_open(tb->cancel_path, O_WRONLY);
 383         if (fd < 0) {
 384             error_report("Could not open TPM cancel path : %s",
 385                          strerror(errno));
 386         }
 387         return fd;
 388     }
 389
 390     dev = strrchr(tpm_pt->tpm_dev, '/');
 391     if (dev) {
 392         dev++;
 393         if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel",
 394                      dev) < sizeof(path)) {
 395             fd = qemu_open(path, O_WRONLY);
 396             if (fd >= 0) {
 397                 tb->cancel_path = g_strdup(path);
 398             } else {
 399                 error_report("tpm_passthrough: Could not open TPM cancel "
 400                              "path %s : %s", path, strerror(errno));
 401             }
 402         }
 403     } else {
 404        error_report("tpm_passthrough: Bad TPM device path %s",
 405                     tpm_pt->tpm_dev);
 406     }
 407
 408     return fd;
 409 }
 410
 411 static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
 412 {
 413     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 414     const char *value;
 415
 416     value = qemu_opt_get(opts, "cancel-path");
 417     tb->cancel_path = g_strdup(value);
 418
 419     value = qemu_opt_get(opts, "path");
 420     if (!value) {
 421         value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
 422     }
 423
 424     tpm_pt->tpm_dev = g_strdup(value);
 425
 426     tb->path = g_strdup(tpm_pt->tpm_dev);
 427
 428     tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
 429     if (tpm_pt->tpm_fd < 0) {
 430         error_report("Cannot access TPM device using '%s': %s",
 431                      tpm_pt->tpm_dev, strerror(errno));
 432         goto err_free_parameters;
 433     }
 434
 435     if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
 436         error_report("'%s' is not a TPM device.",
 437                      tpm_pt->tpm_dev);
 438         goto err_close_tpmdev;
 439     }
 440
 441     return 0;
 442
 443  err_close_tpmdev:
 444     qemu_close(tpm_pt->tpm_fd);
 445     tpm_pt->tpm_fd = -1;
 446
 447  err_free_parameters:
 448     g_free(tb->path);
 449     tb->path = NULL;
 450
 451     g_free(tpm_pt->tpm_dev);
 452     tpm_pt->tpm_dev = NULL;
 453
 454     return 1;
 455 }
 456
 457 static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
 458 {
 459     Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
 460     TPMBackend *tb = TPM_BACKEND(obj);
 461     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 462
 463     tb->id = g_strdup(id);
 464     /* let frontend set the fe_model to proper value */
 465     tb->fe_model = -1;
 466
 467     tb->ops = &tpm_passthrough_driver;
 468
 469     if (tpm_passthrough_handle_device_opts(opts, tb)) {
 470         goto err_exit;
 471     }
 472
 473     tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb);
 474     if (tpm_pt->cancel_fd < 0) {
 475         goto err_exit;
 476     }
 477
 478     return tb;
 479
 480 err_exit:
 481     g_free(tb->id);
 482
 483     return NULL;
 484 }
 485
 486 static void tpm_passthrough_destroy(TPMBackend *tb)
 487 {
 488     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 489
 490     tpm_passthrough_cancel_cmd(tb);
 491
 492     tpm_backend_thread_end(&tpm_pt->tbt);
 493
 494     qemu_close(tpm_pt->tpm_fd);
 495     qemu_close(tpm_pt->cancel_fd);
 496
 497     g_free(tb->id);
 498     g_free(tb->path);
 499     g_free(tb->cancel_path);
 500     g_free(tpm_pt->tpm_dev);
 501 }
 502
 503 static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
 504     TPM_STANDARD_CMDLINE_OPTS,
 505     {
 506         .name = "cancel-path",
 507         .type = QEMU_OPT_STRING,
 508         .help = "Sysfs file entry for canceling TPM commands",
 509     },
 510     {
 511         .name = "path",
 512         .type = QEMU_OPT_STRING,
 513         .help = "Path to TPM device on the host",
 514     },
 515     { /* end of list */ },
 516 };
 517
 518 static const TPMDriverOps tpm_passthrough_driver = {
 519     .type                     = TPM_TYPE_PASSTHROUGH,
 520     .opts                     = tpm_passthrough_cmdline_opts,
 521     .desc                     = tpm_passthrough_create_desc,
 522     .create                   = tpm_passthrough_create,
 523     .destroy                  = tpm_passthrough_destroy,
 524     .init                     = tpm_passthrough_init,
 525     .startup_tpm              = tpm_passthrough_startup_tpm,
 526     .realloc_buffer           = tpm_passthrough_realloc_buffer,
 527     .reset                    = tpm_passthrough_reset,
 528     .had_startup_error        = tpm_passthrough_get_startup_error,
 529     .deliver_request          = tpm_passthrough_deliver_request,
 530     .cancel_cmd               = tpm_passthrough_cancel_cmd,
 531     .get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag,
 532     .reset_tpm_established_flag = tpm_passthrough_reset_tpm_established_flag,
 533     .get_tpm_version          = tpm_passthrough_get_tpm_version,
 534 };
 535
 536 static void tpm_passthrough_inst_init(Object *obj)
 537 {
 538 }
 539
 540 static void tpm_passthrough_inst_finalize(Object *obj)
 541 {
 542 }
 543
 544 static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
 545 {
 546     TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
 547
 548     tbc->ops = &tpm_passthrough_driver;
 549 }
 550
 551 static const TypeInfo tpm_passthrough_info = {
 552     .name = TYPE_TPM_PASSTHROUGH,
 553     .parent = TYPE_TPM_BACKEND,
 554     .instance_size = sizeof(TPMPassthruState),
 555     .class_init = tpm_passthrough_class_init,
 556     .instance_init = tpm_passthrough_inst_init,
 557     .instance_finalize = tpm_passthrough_inst_finalize,
 558 };
 559
 560 static void tpm_passthrough_register(void)
 561 {
 562     type_register_static(&tpm_passthrough_info);
 563     tpm_register_driver(&tpm_passthrough_driver);
 564 }
 565
 566 type_init(tpm_passthrough_register)