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