lib/libtcplay/tcplay_api.c

   1 /*
   2  * Copyright (c) 2011 Alex Hornung <alex@alexhornung.com>.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in
  13  *    the documentation and/or other materials provided with the
  14  *    distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  19  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  20  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  22  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  24  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32 #include <errno.h>
  33 #include <string.h>
  34 #include <stdio.h>
  35 #include <stdarg.h>
  36
  37 #include "tcplay.h"
  38 #include "tcplay_api.h"
  39 #include "tcplay_api_internal.h"
  40
  41
  42 int
  43 tc_api_init(int verbose)
  44 {
  45         int error;
  46
  47         tc_internal_verbose = verbose;
  48
  49         if ((error = tc_play_init()) != 0)
  50                 return TC_ERR;
  51         else
  52                 return TC_OK;
  53 }
  54
  55 int
  56 tc_api_uninit(void)
  57 {
  58         check_and_purge_safe_mem();
  59         return TC_OK;
  60 }
  61
  62
  63 static const char *_caps[] = {
  64         "trim",
  65         NULL
  66 };
  67
  68 int
  69 tc_api_has(const char *feature)
  70 {
  71         const char *cap;
  72         int i;
  73
  74         for (cap = _caps[0], i = 0; cap != NULL; cap = _caps[++i]) {
  75                 if ((strcmp(cap, feature)) == 0)
  76                         return TC_OK;
  77         }
  78
  79         return TC_ERR_UNIMPL;
  80 }
  81
  82 int
  83 tc_api_cipher_iterate(tc_api_cipher_iterator_fn fn, void *priv)
  84 {
  85         int i;
  86         struct tc_cipher_chain *chain;
  87         int klen;
  88         int length;
  89         char buf[1024];
  90
  91         if (fn == NULL) {
  92                 errno = EFAULT;
  93                 return TC_ERR;
  94         }
  95
  96         for (i = 0, chain = tc_cipher_chains[0]; chain != NULL;
  97              chain = tc_cipher_chains[++i]) {
  98                 tc_cipher_chain_sprint(buf, sizeof(buf), chain);
  99                 klen = tc_cipher_chain_klen(chain);
 100                 length = tc_cipher_chain_length(chain);
 101                 if ((fn(priv, buf, klen, length)) < 0)
 102                         break;
 103         }
 104
 105         return TC_OK;
 106 }
 107
 108 int
 109 tc_api_prf_iterate(tc_api_prf_iterator_fn fn, void *priv)
 110 {
 111         int i;
 112
 113         if (fn == NULL) {
 114                 errno = EFAULT;
 115                 return TC_ERR;
 116         }
 117
 118         /* start at 1 due to RIPEMD weirdness... */
 119         for (i = 1; pbkdf_prf_algos[i].name != NULL; i++) {
 120                 if ((fn(priv, pbkdf_prf_algos[i].name)) < 0)
 121                         break;
 122         }
 123
 124         return TC_OK;
 125 }
 126
 127
 128 const char *
 129 tc_api_task_get_error(tc_api_task task __unused)
 130 {
 131         return tc_internal_log_buffer;
 132 }
 133
 134
 135 #define _match(k, v) (strcmp(k, v) == 0)
 136
 137 tc_api_task
 138 tc_api_task_init(const char *op)
 139 {
 140         tc_api_task task = NULL;
 141         int fail = 1;
 142
 143         if ((task = alloc_safe_mem(sizeof(*task))) == NULL) {
 144                 errno = ENOMEM;
 145                 goto out;
 146         }
 147
 148         if ((task->opts = opts_init()) == NULL) {
 149                 errno = ENOMEM;
 150                 goto out;
 151         }
 152
 153         if (_match(op, "create")) {
 154                 task->op = TC_OP_CREATE;
 155         } else if (_match(op, "map")) {
 156                 task->op = TC_OP_MAP;
 157         } else if (_match(op, "unmap")) {
 158                 task->op = TC_OP_UNMAP;
 159         } else if (_match(op, "info")) {
 160                 task->op = TC_OP_INFO;
 161         } else if (_match(op, "info_mapped")) {
 162                 task->op = TC_OP_INFO_MAPPED;
 163         } else if (_match(op, "modify")) {
 164                 task->op = TC_OP_MODIFY;
 165         } else if (_match(op, "restore")) {
 166                 task->op = TC_OP_RESTORE;
 167         } else {
 168                 errno = EINVAL;
 169                 goto out;
 170         }
 171
 172         fail = 0;
 173
 174 out:
 175         if (fail && task != NULL) {
 176                 if (task->opts != NULL)
 177                         opts_free(task->opts);
 178                 free_safe_mem(task);
 179         }
 180
 181         return fail ? NULL : task;
 182 }
 183
 184 int
 185 tc_api_task_uninit(tc_api_task task)
 186 {
 187         if (task->last_info != NULL)
 188                 free_info(task->last_info);
 189         opts_free(task->opts);
 190         free_safe_mem(task);
 191
 192         return TC_OK;
 193 }
 194
 195
 196 #define _set_str(k) \
 197         do {                                                    \
 198                 if ((opts->k = strdup_safe_mem(s)) == NULL) {   \
 199                         errno = ENOMEM;                         \
 200                         r = TC_ERR;                             \
 201                         goto out;                               \
 202                 }                                               \
 203         } while (0)
 204
 205 #define _clr_str(k) \
 206         do {                                                    \
 207                 if (opts->k)                                    \
 208                         free_safe_mem(opts->k);                 \
 209                 opts->k = NULL;                                 \
 210         } while (0)
 211
 212 int
 213 tc_api_task_set(tc_api_task task, const char *key, ...)
 214 {
 215         struct tcplay_opts *opts;
 216         va_list ap;
 217         const char *s;
 218         int64_t i64;
 219         int i;
 220         tc_api_state_change_fn sc_fn;
 221         void *vp;
 222         int r = TC_OK;
 223
 224         if (task == NULL || ((opts = task->opts) == NULL)) {
 225                 errno = EFAULT;
 226                 return TC_ERR;
 227         }
 228
 229         va_start(ap, key);
 230
 231         if (_match(key, "interactive")) {
 232                 i = va_arg(ap, int);
 233                 opts->interactive = i;
 234         } else if (_match(key, "weak_keys_and_salt")) {
 235                 i = va_arg(ap, int);
 236                 opts->weak_keys_and_salt = i;
 237         } else if (_match(key, "secure_erase")) {
 238                 i = va_arg(ap, int);
 239                 opts->secure_erase = i;
 240         } else if (_match(key, "protect_hidden")) {
 241                 i = va_arg(ap, int);
 242                 opts->protect_hidden = i;
 243         } else if (_match(key, "fde")) {
 244                 i = va_arg(ap, int);
 245                 if (i)
 246                         opts->flags |= TC_FLAG_FDE;
 247                 else
 248                         opts->flags &= ~TC_FLAG_FDE;
 249         } else if (_match(key, "use_backup_header")) {
 250                 i = va_arg(ap, int);
 251                 if (i)
 252                         opts->flags |= TC_FLAG_BACKUP;
 253                 else
 254                         opts->flags &= ~TC_FLAG_BACKUP;
 255         } else if (_match(key, "allow_trim")) {
 256                 i = va_arg(ap, int);
 257                 if (i)
 258                         opts->flags |= TC_FLAG_ALLOW_TRIM;
 259                 else
 260                         opts->flags &= ~TC_FLAG_ALLOW_TRIM;
 261         } else if (_match(key, "hidden_size_bytes")) {
 262                 i64 = va_arg(ap, int64_t);
 263                 opts->hidden_size_bytes = (disksz_t)i64;
 264                 opts->hidden = (i64 > 0);
 265         } else if (_match(key, "retries")) {
 266                 i = va_arg(ap, int);
 267                 opts->retries = i;
 268         } else if (_match(key, "timeout")) {
 269                 i = va_arg(ap, int);
 270                 opts->timeout = (time_t)i;
 271         } else if (_match(key, "save_header_to_file")) {
 272                 s = va_arg(ap, const char *);
 273                 if (s != NULL) {
 274                         _set_str(hdr_file_out);
 275                         opts->flags |= TC_FLAG_SAVE_TO_FILE;
 276                 } else {
 277                         _clr_str(hdr_file_out);
 278                         opts->flags &= ~TC_FLAG_SAVE_TO_FILE;
 279                 }
 280         } else if (_match(key, "header_from_file")) {
 281                 s = va_arg(ap, const char *);
 282                 if (s != NULL) {
 283                         _set_str(hdr_file_in);
 284                         opts->flags |= TC_FLAG_HDR_FROM_FILE;
 285                 } else {
 286                         _clr_str(hdr_file_in);
 287                         opts->flags &= ~TC_FLAG_HDR_FROM_FILE;
 288                 }
 289         } else if (_match(key, "hidden_header_from_file")) {
 290                 s = va_arg(ap, const char *);
 291                 if (s != NULL) {
 292                         _set_str(h_hdr_file_in);
 293                         opts->flags |= TC_FLAG_H_HDR_FROM_FILE;
 294                 } else {
 295                         _clr_str(h_hdr_file_in);
 296                         opts->flags &= ~TC_FLAG_H_HDR_FROM_FILE;
 297                 }
 298         } else if (_match(key, "sys")) {
 299                 s = va_arg(ap, const char *);
 300                 if (s != NULL) {
 301                         _set_str(sys_dev);
 302                         opts->flags |= TC_FLAG_SYS;
 303                 } else {
 304                         _clr_str(sys_dev);
 305                         opts->flags &= ~TC_FLAG_SYS;
 306                 }
 307         } else if (_match(key, "passphrase")) {
 308                 s = va_arg(ap, const char *);
 309                 if (s != NULL) {
 310                         _set_str(passphrase);
 311                 } else {
 312                         _clr_str(passphrase);
 313                 }
 314         } else if (_match(key, "h_passphrase")) {
 315                 s = va_arg(ap, const char *);
 316                 if (s != NULL) {
 317                         _set_str(h_passphrase);
 318                 } else {
 319                         _clr_str(h_passphrase);
 320                 }
 321         } else if (_match(key, "new_passphrase")) {
 322                 s = va_arg(ap, const char *);
 323                 if (s != NULL) {
 324                         _set_str(new_passphrase);
 325                 } else {
 326                         _clr_str(new_passphrase);
 327                 }
 328         } else if (_match(key, "dev")) {
 329                 s = va_arg(ap, const char *);
 330                 if (s != NULL) {
 331                         _set_str(dev);
 332                 } else {
 333                         _clr_str(dev);
 334                 }
 335         } else if (_match(key, "map_name")) {
 336                 s = va_arg(ap, const char *);
 337                 if (s != NULL) {
 338                         _set_str(map_name);
 339                 } else {
 340                         _clr_str(map_name);
 341                 }
 342         } else if (_match(key, "keyfiles")) {
 343                 s = va_arg(ap, const char *);
 344                 if (s != NULL) {
 345                         opts_add_keyfile(opts, s);
 346                 } else {
 347                         opts_clear_keyfile(opts);
 348                 }
 349         } else if (_match(key, "h_keyfiles")) {
 350                 s = va_arg(ap, const char *);
 351                 if (s != NULL) {
 352                         opts_add_keyfile_hidden(opts, s);
 353                 } else {
 354                         opts_clear_keyfile_hidden(opts);
 355                 }
 356         } else if (_match(key, "new_keyfiles")) {
 357                 s = va_arg(ap, const char *);
 358                 if (s != NULL) {
 359                         opts_add_keyfile_new(opts, s);
 360                 } else {
 361                         opts_clear_keyfile_new(opts);
 362                 }
 363         } else if (_match(key, "prf_algo")) {
 364                 s = va_arg(ap, const char *);
 365                 if (s != NULL) {
 366                         if ((opts->prf_algo = check_prf_algo(s, 1)) == NULL) {
 367                                 errno = ENOENT;
 368                                 r = TC_ERR;
 369                                 goto out;
 370                         }
 371                 } else {
 372                         opts->prf_algo = NULL;
 373                 }
 374         } else if (_match(key, "h_prf_algo")) {
 375                 s = va_arg(ap, const char *);
 376                 if (s != NULL) {
 377                         if ((opts->h_prf_algo = check_prf_algo(s, 1)) == NULL) {
 378                                 errno = ENOENT;
 379                                 r = TC_ERR;
 380                                 goto out;
 381                         }
 382                 } else {
 383                         opts->h_prf_algo = NULL;
 384                 }
 385         } else if (_match(key, "new_prf_algo")) {
 386                 s = va_arg(ap, const char *);
 387                 if (s != NULL) {
 388                         if ((opts->new_prf_algo = check_prf_algo(s, 1)) == NULL) {
 389                                 errno = ENOENT;
 390                                 r = TC_ERR;
 391                                 goto out;
 392                         }
 393                 } else {
 394                         opts->new_prf_algo = NULL;
 395                 }
 396         } else if (_match(key, "cipher_chain")) {
 397                 s = va_arg(ap, const char *);
 398                 if (s != NULL) {
 399                         if ((opts->cipher_chain = check_cipher_chain(s, 1)) == NULL) {
 400                                 errno = ENOENT;
 401                                 r = TC_ERR;
 402                                 goto out;
 403                         }
 404                 } else {
 405                         opts->cipher_chain = NULL;
 406                 }
 407         } else if (_match(key, "h_cipher_chain")) {
 408                 s = va_arg(ap, const char *);
 409                 if (s != NULL) {
 410                         if ((opts->h_cipher_chain = check_cipher_chain(s, 1)) == NULL) {
 411                                 errno = ENOENT;
 412                                 r = TC_ERR;
 413                                 goto out;
 414                         }
 415                 } else {
 416                         opts->h_cipher_chain = NULL;
 417                 }
 418         } else if (_match(key, "state_change_fn")) {
 419                 sc_fn = va_arg(ap, tc_api_state_change_fn);
 420                 opts->state_change_fn = sc_fn;
 421                 vp = va_arg(ap, void *);
 422                 opts->api_ctx = vp;
 423         } else {
 424                 r = TC_ERR_UNIMPL;
 425         }
 426
 427 out:
 428         va_end(ap);
 429
 430         return r;
 431 }
 432
 433 #define _not_null(x) \
 434         if (opts->x == NULL) {  \
 435                 return -1;      \
 436         }
 437
 438 #define _null(x) \
 439         if (opts->x != NULL) {  \
 440                 return -1;      \
 441         }
 442
 443 #define _zero(x) \
 444         if (opts->x != 0) {     \
 445                 return -1;      \
 446         }
 447
 448 #define _not_set(x) \
 449         if (TC_FLAG_SET(opts->flags, x)) {      \
 450                 return -1;                      \
 451         }
 452
 453 static
 454 int
 455 _opts_check_create(struct tcplay_opts *opts)
 456 {
 457         _not_null(dev);
 458         _not_set(SYS);
 459         _not_set(FDE);
 460         _not_set(BACKUP);
 461         _not_set(ONLY_RESTORE);
 462         _not_set(ALLOW_TRIM);
 463         _not_set(SAVE_TO_FILE);
 464         _not_set(HDR_FROM_FILE);
 465         _not_set(H_HDR_FROM_FILE);
 466
 467         _null(map_name);
 468         _zero(protect_hidden);
 469         _null(new_passphrase);
 470         _null(new_prf_algo);
 471         _zero(n_newkeyfiles);
 472
 473         if (opts->hidden_size_bytes && !opts->hidden) {
 474                 return -1;
 475         }
 476
 477         return 0;
 478 }
 479
 480 static
 481 int
 482 _opts_check_map(struct tcplay_opts *opts)
 483 {
 484         _not_null(dev);
 485         _not_null(map_name);
 486         _not_set(ONLY_RESTORE);
 487         _not_set(SAVE_TO_FILE);
 488         _zero(hidden);
 489         _zero(hidden_size_bytes);
 490         _null(new_passphrase);
 491         _null(new_prf_algo);
 492         _zero(n_newkeyfiles);
 493         _null(prf_algo);
 494         _null(h_prf_algo);
 495         _null(cipher_chain);
 496         _null(h_cipher_chain);
 497
 498         if (!opts->protect_hidden) {
 499                 _zero(n_hkeyfiles);
 500                 //_null(h_passphrase);
 501         }
 502
 503         return 0;
 504 }
 505
 506 static
 507 int
 508 _opts_check_unmap(struct tcplay_opts *opts)
 509 {
 510         _not_null(map_name);
 511         /* XXX: _not_null(dev); ? */
 512         _zero(nkeyfiles);
 513         _zero(n_hkeyfiles);
 514         _null(prf_algo);
 515         _null(cipher_chain);
 516         _null(h_prf_algo);
 517         _null(h_cipher_chain);
 518         _null(passphrase);
 519         _null(h_passphrase);
 520         _zero(hidden);
 521         _zero(protect_hidden);
 522         _null(new_prf_algo);
 523         _null(new_passphrase);
 524         _zero(n_newkeyfiles);
 525         _not_set(SYS);
 526         _not_set(FDE);
 527         _not_set(BACKUP);
 528         _not_set(ONLY_RESTORE);
 529         _not_set(ALLOW_TRIM);
 530         _not_set(SAVE_TO_FILE);
 531         _not_set(HDR_FROM_FILE);
 532         _not_set(H_HDR_FROM_FILE);
 533
 534         return 0;
 535 }
 536
 537 static
 538 int
 539 _opts_check_info(struct tcplay_opts *opts)
 540 {
 541         _not_null(dev);
 542         _null(map_name);
 543         _not_set(ONLY_RESTORE);
 544         _not_set(SAVE_TO_FILE);
 545         _zero(hidden);
 546         _zero(hidden_size_bytes);
 547         _null(new_passphrase);
 548         _null(new_prf_algo);
 549         _zero(n_newkeyfiles);
 550         _null(prf_algo);
 551         _null(h_prf_algo);
 552         _null(cipher_chain);
 553         _null(h_cipher_chain);
 554
 555         if (!opts->protect_hidden) {
 556                 _zero(n_hkeyfiles);
 557                 //_null(h_passphrase);
 558         }
 559
 560         return 0;
 561 }
 562
 563 static
 564 int
 565 _opts_check_info_mapped(struct tcplay_opts *opts)
 566 {
 567         _not_null(map_name);
 568         /* XXX: _not_null(dev); ? */
 569         _zero(nkeyfiles);
 570         _zero(n_hkeyfiles);
 571         _null(prf_algo);
 572         _null(cipher_chain);
 573         _null(h_prf_algo);
 574         _null(h_cipher_chain);
 575         _null(passphrase);
 576         _null(h_passphrase);
 577         _zero(hidden);
 578         _zero(protect_hidden);
 579         _null(new_prf_algo);
 580         _null(new_passphrase);
 581         _zero(n_newkeyfiles);
 582         _not_set(SYS);
 583         _not_set(FDE);
 584         _not_set(BACKUP);
 585         _not_set(ONLY_RESTORE);
 586         _not_set(ALLOW_TRIM);
 587         _not_set(SAVE_TO_FILE);
 588         _not_set(HDR_FROM_FILE);
 589         _not_set(H_HDR_FROM_FILE);
 590
 591         return 0;
 592 }
 593
 594 static
 595 int
 596 _opts_check_modify(struct tcplay_opts *opts)
 597 {
 598         _not_null(dev);
 599         _null(map_name);
 600         _zero(hidden);
 601         _zero(hidden_size_bytes);
 602         _null(prf_algo);
 603         _null(h_prf_algo);
 604         _null(cipher_chain);
 605         _null(h_cipher_chain);
 606
 607         if (!opts->protect_hidden) {
 608                 _zero(n_hkeyfiles);
 609                 _null(h_passphrase);
 610         }
 611
 612         return 0;
 613 }
 614
 615
 616 static
 617 int
 618 _opts_check_restore(struct tcplay_opts *opts)
 619 {
 620         if ((_opts_check_modify(opts)) < 0)
 621                 return -1;
 622
 623         _null(new_prf_algo);
 624         _zero(n_newkeyfiles);
 625         _null(new_passphrase);
 626
 627         return 0;
 628 }
 629
 630 int
 631 tc_api_task_do(tc_api_task task)
 632 {
 633         struct tcplay_opts *opts;
 634         int r = TC_OK;
 635
 636         if (task == NULL || ((opts = task->opts) == NULL)) {
 637                 errno = EFAULT;
 638                 return TC_ERR;
 639         }
 640
 641         if (task->last_info != NULL) {
 642                 free_info(task->last_info);
 643         }
 644
 645         switch (task->op) {
 646         case TC_OP_CREATE:
 647                 if ((r = _opts_check_create(task->opts)) != 0) {
 648                         errno = EINVAL;
 649                         return r;
 650                 }
 651                 r = create_volume(opts);
 652                 break;
 653
 654         case TC_OP_MAP:
 655                 if ((r = _opts_check_map(task->opts)) != 0) {
 656                         errno = EINVAL;
 657                         return r;
 658                 }
 659                 r = map_volume(opts);
 660                 break;
 661
 662         case TC_OP_UNMAP:
 663                 if ((r = _opts_check_unmap(task->opts)) != 0) {
 664                         errno = EINVAL;
 665                         return r;
 666                 }
 667                 r = dm_teardown(opts->map_name, opts->dev);
 668                 break;
 669
 670         case TC_OP_INFO:
 671                 if ((r = _opts_check_info(task->opts)) != 0) {
 672                         errno = EINVAL;
 673                         return r;
 674                 }
 675                 if ((task->last_info = info_map_common(opts, NULL)) == NULL) {
 676                         r = TC_ERR;
 677                 }
 678                 break;
 679
 680         case TC_OP_INFO_MAPPED:
 681                 if ((r = _opts_check_info_mapped(task->opts)) != 0) {
 682                         errno = EINVAL;
 683                         return r;
 684                 }
 685                 if ((task->last_info = dm_info_map(opts->map_name)) == NULL) {
 686                         r = TC_ERR;
 687                 }
 688                 break;
 689
 690         case TC_OP_MODIFY:
 691                 if ((r = _opts_check_modify(task->opts)) != 0) {
 692                         errno = EINVAL;
 693                         return r;
 694                 }
 695                 r = modify_volume(opts);
 696                 break;
 697
 698         case TC_OP_RESTORE:
 699                 if ((r = _opts_check_restore(task->opts)) != 0) {
 700                         errno = EINVAL;
 701                         return r;
 702                 }
 703                 opts->flags |= TC_FLAG_ONLY_RESTORE;
 704                 r = modify_volume(opts);
 705                 opts->flags &= ~TC_FLAG_ONLY_RESTORE;
 706                 break;
 707         }
 708
 709         return r;
 710 }
 711
 712
 713 int
 714 tc_api_task_info_get(tc_api_task task, const char *key, ...)
 715 {
 716         char buf[1024];
 717         va_list ap;
 718         struct tcplay_info *info;
 719         char *s;
 720         int *ip;
 721         int64_t *i64p;
 722         int r = TC_OK;
 723         size_t sz;
 724
 725         if (task == NULL || ((info = task->last_info) == NULL)) {
 726                 errno = EFAULT;
 727                 return TC_ERR;
 728         }
 729
 730         va_start(ap, key);
 731         sz = va_arg(ap, size_t);
 732         if (sz < 1) {
 733                 errno = EINVAL;
 734                 r = TC_ERR;
 735                 goto out;
 736         }
 737
 738         if (_match(key, "device")) {
 739                 s = va_arg(ap, char *);
 740                 strncpy(s, info->dev, sz);
 741                 s[sz-1] = '\0';
 742         } else if (_match(key, "cipher")) {
 743                 s = va_arg(ap, char *);
 744                 tc_cipher_chain_sprint(buf, sizeof(buf), info->cipher_chain);
 745                 strncpy(s, buf, sz);
 746                 s[sz-1] = '\0';
 747         } else if (_match(key, "prf")) {
 748                 s = va_arg(ap, char *);
 749                 if (info->pbkdf_prf)
 750                         strncpy(s, info->pbkdf_prf->name, sz);
 751                 else
 752                         strncpy(s, "(unknown)", sz);
 753                 s[sz-1] = '\0';
 754         } else if (_match(key, "key_bits")) {
 755                 if (sz != sizeof(int)) {
 756                         errno = EFAULT;
 757                         r = TC_ERR;
 758                         goto out;
 759                 }
 760                 ip = va_arg(ap, int *);
 761                 *ip = 8*tc_cipher_chain_klen(info->cipher_chain);
 762         } else if (_match(key, "size")) {
 763                 if (sz != sizeof(int64_t)) {
 764                         errno = EFAULT;
 765                         r = TC_ERR;
 766                         goto out;
 767                 }
 768                 i64p = va_arg(ap, int64_t *);
 769                 if (info->hdr)
 770                         *i64p = (int64_t)info->size * (int64_t)info->hdr->sec_sz;
 771                 else
 772                         *i64p = (int64_t)info->size * (int64_t)info->blk_sz;
 773         } else if (_match(key, "iv_offset")) {
 774                 if (sz != sizeof(int64_t)) {
 775                         errno = EFAULT;
 776                         r = TC_ERR;
 777                         goto out;
 778                 }
 779                 i64p = va_arg(ap, int64_t *);
 780                 if (info->hdr)
 781                         *i64p = (int64_t)info->skip * (int64_t)info->hdr->sec_sz;
 782                 else
 783                         *i64p = (int64_t)info->skip * (int64_t)info->blk_sz;
 784         } else if (_match(key, "block_offset")) {
 785                 if (sz != sizeof(int64_t)) {
 786                         errno = EFAULT;
 787                         r = TC_ERR;
 788                         goto out;
 789                 }
 790                 i64p = va_arg(ap, int64_t *);
 791                 if (info->hdr)
 792                         *i64p = (int64_t)info->offset * (int64_t)info->hdr->sec_sz;
 793                 else
 794                         *i64p = (int64_t)info->offset * (int64_t)info->blk_sz;
 795         } else {
 796                 r = TC_ERR_UNIMPL;
 797         }
 798
 799 out:
 800         va_end(ap);
 801
 802         return r;
 803 }