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