lib/tcrypt/tcrypt.c

   1 /*
   2  * TCRYPT compatible volume handling
   3  *
   4  * Copyright (C) 2012, Red Hat, Inc. All rights reserved.
   5  * Copyright (C) 2012, Milan Broz
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * version 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <fcntl.h>
  26 #include <assert.h>
  27
  28 #include "libcryptsetup.h"
  29 #include "tcrypt.h"
  30 #include "internal.h"
  31
  32 /* TCRYPT PBKDF variants */
  33 static struct {
  34         unsigned int legacy:1;
  35         char *name;
  36         char *hash;
  37         unsigned int iterations;
  38 } tcrypt_kdf[] = {
  39         { 0, "pbkdf2", "ripemd160", 2000 },
  40         { 0, "pbkdf2", "ripemd160", 1000 },
  41         { 0, "pbkdf2", "sha512",    1000 },
  42         { 0, "pbkdf2", "whirlpool", 1000 },
  43         { 1, "pbkdf2", "sha1",      2000 },
  44         { 0, NULL,     NULL,           0 }
  45 };
  46
  47 struct tcrypt_alg {
  48                 const char *name;
  49                 unsigned int key_size;
  50                 unsigned int iv_size;
  51                 unsigned int key_offset;
  52                 unsigned int iv_offset; /* or tweak key offset */
  53 };
  54
  55 struct tcrypt_algs {
  56         unsigned int legacy:1;
  57         unsigned int chain_count;
  58         unsigned int chain_key_size;
  59         const char *long_name;
  60         const char *mode;
  61         struct tcrypt_alg cipher[3];
  62 };
  63
  64 /* TCRYPT cipher variants */
  65 static struct tcrypt_algs tcrypt_cipher[] = {
  66 /* XTS mode */
  67 {0,1,64,"aes","xts-plain64",
  68         {{"aes",    64,16,0,32}}},
  69 {0,1,64,"serpent","xts-plain64",
  70         {{"serpent",64,16,0,32}}},
  71 {0,1,64,"twofish","xts-plain64",
  72         {{"twofish",64,16,0,32}}},
  73 {0,2,128,"twofish-aes","xts-plain64",
  74         {{"twofish",64,16, 0,64},
  75          {"aes",    64,16,32,96}}},
  76 {0,3,192,"serpent-twofish-aes","xts-plain64",
  77         {{"serpent",64,16, 0, 96},
  78          {"twofish",64,16,32,128},
  79          {"aes",    64,16,64,160}}},
  80 {0,2,128,"aes-serpent","xts-plain64",
  81         {{"aes",    64,16, 0,64},
  82          {"serpent",64,16,32,96}}},
  83 {0,3,192,"aes-twofish-serpent","xts-plain64",
  84         {{"aes",    64,16, 0, 96},
  85          {"twofish",64,16,32,128},
  86          {"serpent",64,16,64,160}}},
  87 {0,2,128,"serpent-twofish","xts-plain64",
  88         {{"serpent",64,16, 0,64},
  89          {"twofish",64,16,32,96}}},
  90 /* LRW mode */
  91 {0,1,48,"aes","lrw-benbi",
  92         {{"aes",    48,16,32,0}}},
  93 {0,1,48,"serpent","lrw-benbi",
  94         {{"serpent",48,16,32,0}}},
  95 {0,1,48,"twofish","lrw-benbi",
  96         {{"twofish",48,16,32,0}}},
  97 {0,2,96,"twofish-aes","lrw-benbi",
  98         {{"twofish",48,16,32,0},
  99          {"aes",    48,16,64,0}}},
 100 {0,3,144,"serpent-twofish-aes","lrw-benbi",
 101         {{"serpent",48,16,32,0},
 102          {"twofish",48,16,64,0},
 103          {"aes",    48,16,96,0}}},
 104 {0,2,96,"aes-serpent","lrw-benbi",
 105         {{"aes",    48,16,32,0},
 106          {"serpent",48,16,64,0}}},
 107 {0,3,144,"aes-twofish-serpent","lrw-benbi",
 108         {{"aes",    48,16,32,0},
 109          {"twofish",48,16,64,0},
 110          {"serpent",48,16,96,0}}},
 111 {0,2,96,"serpent-twofish", "lrw-benbi",
 112         {{"serpent",48,16,32,0},
 113          {"twofish",48,16,64,0}}},
 114 /* Kernel LRW block size is fixed to 16 bytes for GF(2^128)
 115  * thus cannot be used with blowfish where block is 8 bytes.
 116  * There also no GF(2^64) support.
 117 {1,1,64,"blowfish_le","lrw-benbi",
 118          {{"blowfish_le",64,8,32,0}}},
 119 {1,2,112,"blowfish_le-aes","lrw-benbi",
 120          {{"blowfish_le",64, 8,32,0},
 121           {"aes",        48,16,88,0}}},
 122 {1,3,160,"serpent-blowfish_le-aes","lrw-benbi",
 123           {{"serpent",    48,16, 32,0},
 124            {"blowfish_le",64, 8, 64,0},
 125            {"aes",        48,16,120,0}}},*/
 126 /* CBC + "outer" CBC (both with whitening) */
 127 {1,1,32,"aes","cbc-tcrypt",
 128         {{"aes",    32,16,32,0}}},
 129 {1,1,32,"serpent","cbc-tcrypt",
 130         {{"serpent",32,16,32,0}}},
 131 {1,1,32,"twofish","cbc-tcrypt",
 132         {{"twofish",32,16,32,0}}},
 133 {1,2,64,"twofish-aes","cbci-tcrypt",
 134         {{"twofish",32,16,32,0},
 135          {"aes",    32,16,64,0}}},
 136 {1,3,96,"serpent-twofish-aes","cbci-tcrypt",
 137         {{"serpent",32,16,32,0},
 138          {"twofish",32,16,64,0},
 139          {"aes",    32,16,96,0}}},
 140 {1,2,64,"aes-serpent","cbci-tcrypt",
 141         {{"aes",    32,16,32,0},
 142          {"serpent",32,16,64,0}}},
 143 {1,3,96,"aes-twofish-serpent", "cbci-tcrypt",
 144         {{"aes",    32,16,32,0},
 145          {"twofish",32,16,64,0},
 146          {"serpent",32,16,96,0}}},
 147 {1,2,64,"serpent-twofish", "cbci-tcrypt",
 148         {{"serpent",32,16,32,0},
 149          {"twofish",32,16,64,0}}},
 150 {1,1,16,"cast5","cbc-tcrypt",
 151         {{"cast5",   16,8,32,0}}},
 152 {1,1,24,"des3_ede","cbc-tcrypt",
 153         {{"des3_ede",24,8,32,0}}},
 154 {1,1,56,"blowfish_le","cbc-tcrypt",
 155         {{"blowfish_le",56,8,32,0}}},
 156 {1,2,88,"blowfish_le-aes","cbc-tcrypt",
 157         {{"blowfish_le",56, 8,32,0},
 158          {"aes",        32,16,88,0}}},
 159 {1,3,120,"serpent-blowfish_le-aes","cbc-tcrypt",
 160         {{"serpent",    32,16, 32,0},
 161          {"blowfish_le",56, 8, 64,0},
 162          {"aes",        32,16,120,0}}},
 163 {}
 164 };
 165
 166 static int hdr_from_disk(struct tcrypt_phdr *hdr,
 167                          struct crypt_params_tcrypt *params,
 168                          int kdf_index, int cipher_index)
 169 {
 170         uint32_t crc32;
 171         size_t size;
 172
 173         /* Check CRC32 of header */
 174         size = TCRYPT_HDR_LEN - sizeof(hdr->d.keys) - sizeof(hdr->d.header_crc32);
 175         crc32 = crypt_crc32(~0, (unsigned char*)&hdr->d, size) ^ ~0;
 176         if (be16_to_cpu(hdr->d.version) > 3 &&
 177             crc32 != be32_to_cpu(hdr->d.header_crc32)) {
 178                 log_dbg("TCRYPT header CRC32 mismatch.");
 179                 return -EINVAL;
 180         }
 181
 182         /* Check CRC32 of keys */
 183         crc32 = crypt_crc32(~0, (unsigned char*)hdr->d.keys, sizeof(hdr->d.keys)) ^ ~0;
 184         if (crc32 != be32_to_cpu(hdr->d.keys_crc32)) {
 185                 log_dbg("TCRYPT keys CRC32 mismatch.");
 186                 return -EINVAL;
 187         }
 188
 189         /* Convert header to cpu format */
 190         hdr->d.version  =  be16_to_cpu(hdr->d.version);
 191         hdr->d.version_tc = le16_to_cpu(hdr->d.version_tc);
 192
 193         hdr->d.keys_crc32 = be32_to_cpu(hdr->d.keys_crc32);
 194
 195         hdr->d.hidden_volume_size = be64_to_cpu(hdr->d.hidden_volume_size);
 196         hdr->d.volume_size        = be64_to_cpu(hdr->d.volume_size);
 197
 198         hdr->d.mk_offset = be64_to_cpu(hdr->d.mk_offset);
 199         if (!hdr->d.mk_offset)
 200                 hdr->d.mk_offset = 512;
 201
 202         hdr->d.mk_size = be64_to_cpu(hdr->d.mk_size);
 203
 204         hdr->d.flags = be32_to_cpu(hdr->d.flags);
 205
 206         hdr->d.sector_size = be32_to_cpu(hdr->d.sector_size);
 207         if (!hdr->d.sector_size)
 208                 hdr->d.sector_size = 512;
 209
 210         hdr->d.header_crc32 = be32_to_cpu(hdr->d.header_crc32);
 211
 212         /* Set params */
 213         params->passphrase = NULL;
 214         params->passphrase_size = 0;
 215         params->hash_name  = tcrypt_kdf[kdf_index].hash;
 216         params->key_size = tcrypt_cipher[cipher_index].chain_key_size;
 217         params->cipher = tcrypt_cipher[cipher_index].long_name;
 218         params->mode = tcrypt_cipher[cipher_index].mode;
 219
 220         return 0;
 221 }
 222
 223 /*
 224  * Kernel implements just big-endian version of blowfish, hack it here
 225  */
 226 static void blowfish_le(char *buf)
 227 {
 228         uint32_t *l = (uint32_t*)&buf[0];
 229         uint32_t *r = (uint32_t*)&buf[4];
 230         *l = swab32(*l);
 231         *r = swab32(*r);
 232 }
 233
 234 static int decrypt_blowfish_le_cbc(struct tcrypt_alg *alg,
 235                                    const char *key, char *buf)
 236 {
 237         char iv[alg->iv_size], iv_old[alg->iv_size];
 238         struct crypt_cipher *cipher = NULL;
 239         int bs = alg->iv_size;
 240         int i, j, r;
 241
 242         assert(bs == 2*sizeof(uint32_t));
 243
 244         r = crypt_cipher_init(&cipher, "blowfish", "ecb",
 245                               &key[alg->key_offset], alg->key_size);
 246         if (r < 0)
 247                 return r;
 248
 249         memcpy(iv, &key[alg->iv_offset], alg->iv_size);
 250         for (i = 0; i < TCRYPT_HDR_LEN; i += bs) {
 251                 memcpy(iv_old, &buf[i], bs);
 252                 blowfish_le(&buf[i]);
 253                 r = crypt_cipher_decrypt(cipher, &buf[i], &buf[i],
 254                                           bs, NULL, 0);
 255                 blowfish_le(&buf[i]);
 256                 if (r < 0)
 257                         break;
 258                 for (j = 0; j < bs; j++)
 259                         buf[i + j] ^= iv[j];
 260                 memcpy(iv, iv_old, bs);
 261         }
 262
 263         crypt_cipher_destroy(cipher);
 264         return r;
 265 }
 266
 267 static void remove_whitening(char *buf, const char *key)
 268 {
 269         int j;
 270
 271         for (j = 0; j < TCRYPT_HDR_LEN; j++)
 272                 buf[j] ^= key[j % 8];
 273 }
 274
 275 static void copy_key(struct tcrypt_alg *alg, const char *mode,
 276                      char *out_key, const char *key)
 277 {
 278         int ks2;
 279         if (!strncmp(mode, "xts", 3)) {
 280                 ks2 = alg->key_size / 2;
 281                 memcpy(out_key, &key[alg->key_offset], ks2);
 282                 memcpy(&out_key[ks2], &key[alg->iv_offset], ks2);
 283         } else if (!strncmp(mode, "lrw", 3)) {
 284                 ks2 = alg->key_size - TCRYPT_LRW_IKEY_LEN;
 285                 memcpy(out_key, &key[alg->key_offset], ks2);
 286                 memcpy(&out_key[ks2], key, TCRYPT_LRW_IKEY_LEN);
 287         } else if (!strncmp(mode, "cbc", 3)) {
 288                 memcpy(out_key, &key[alg->key_offset], alg->key_size);
 289         }
 290 }
 291
 292 static int decrypt_hdr_one(struct tcrypt_alg *alg, const char *mode,
 293                            const char *key,struct tcrypt_phdr *hdr)
 294 {
 295         char backend_key[TCRYPT_HDR_KEY_LEN];
 296         char iv[TCRYPT_HDR_IV_LEN] = {};
 297         char mode_name[MAX_CIPHER_LEN];
 298         struct crypt_cipher *cipher;
 299         char *c, *buf = (char*)&hdr->e;
 300         int r;
 301
 302         /* Remove IV if present */
 303         strncpy(mode_name, mode, MAX_CIPHER_LEN);
 304         c = strchr(mode_name, '-');
 305         if (c)
 306                 *c = '\0';
 307
 308         if (!strncmp(mode, "lrw", 3))
 309                 iv[alg->iv_size - 1] = 1;
 310         else if (!strncmp(mode, "cbc", 3)) {
 311                 remove_whitening(buf, &key[8]);
 312                 if (!strcmp(alg->name, "blowfish_le"))
 313                         return decrypt_blowfish_le_cbc(alg, key, buf);
 314                 memcpy(iv, &key[alg->iv_offset], alg->iv_size);
 315         }
 316
 317         copy_key(alg, mode, backend_key, key);
 318         r = crypt_cipher_init(&cipher, alg->name, mode_name,
 319                               backend_key, alg->key_size);
 320         memset(backend_key, 0, sizeof(backend_key));
 321         if (r < 0)
 322                 return r;
 323
 324         r = crypt_cipher_decrypt(cipher, buf, buf, TCRYPT_HDR_LEN, iv, alg->iv_size);
 325         crypt_cipher_destroy(cipher);
 326
 327         return r;
 328 }
 329
 330 /*
 331  * For chanined ciphers and CBC mode we need "outer" decryption.
 332  * Backend doesn't provide this, so implement it here directly using ECB.
 333  */
 334 static int decrypt_hdr_cbci(struct tcrypt_algs *ciphers,
 335                              const char *key, struct tcrypt_phdr *hdr)
 336 {
 337         struct crypt_cipher *cipher[ciphers->chain_count];
 338         int bs = ciphers->cipher[0].iv_size;
 339         char *buf = (char*)&hdr->e, iv[bs], iv_old[bs];
 340         int i, j, r = -EINVAL;
 341
 342         remove_whitening(buf, &key[8]);
 343
 344         memcpy(iv, &key[ciphers->cipher[0].iv_offset], bs);
 345
 346         /* Initialize all ciphers in chain in ECB mode */
 347         for (j = 0; j < ciphers->chain_count; j++)
 348                 cipher[j] = NULL;
 349         for (j = 0; j < ciphers->chain_count; j++) {
 350                 r = crypt_cipher_init(&cipher[j], ciphers->cipher[j].name, "ecb",
 351                                       &key[ciphers->cipher[j].key_offset],
 352                                       ciphers->cipher[j].key_size);
 353                 if (r < 0)
 354                         goto out;
 355         }
 356
 357         /* Implements CBC with chained ciphers in loop inside */
 358         for (i = 0; i < TCRYPT_HDR_LEN; i += bs) {
 359                 memcpy(iv_old, &buf[i], bs);
 360                 for (j = ciphers->chain_count - 1; j >= 0; j--) {
 361                         r = crypt_cipher_decrypt(cipher[j], &buf[i], &buf[i],
 362                                                   bs, NULL, 0);
 363                         if (r < 0)
 364                                 goto out;
 365                 }
 366                 for (j = 0; j < bs; j++)
 367                         buf[i + j] ^= iv[j];
 368                 memcpy(iv, iv_old, bs);
 369         }
 370 out:
 371         for (j = 0; j < ciphers->chain_count; j++)
 372                 if (cipher[j])
 373                         crypt_cipher_destroy(cipher[j]);
 374
 375         return r;
 376 }
 377
 378 static int decrypt_hdr(struct crypt_device *cd, struct tcrypt_phdr *hdr,
 379                         const char *key, int legacy_modes)
 380 {
 381         struct tcrypt_phdr hdr2;
 382         int i, j, r = -EINVAL;
 383
 384         for (i = 0; tcrypt_cipher[i].chain_count; i++) {
 385                 if (!legacy_modes && tcrypt_cipher[i].legacy)
 386                         continue;
 387                 log_dbg("TCRYPT:  trying cipher %s-%s",
 388                         tcrypt_cipher[i].long_name, tcrypt_cipher[i].mode);
 389
 390                 memcpy(&hdr2.e, &hdr->e, TCRYPT_HDR_LEN);
 391
 392                 if (!strncmp(tcrypt_cipher[i].mode, "cbci", 4))
 393                         r = decrypt_hdr_cbci(&tcrypt_cipher[i], key, &hdr2);
 394                 else for (j = tcrypt_cipher[i].chain_count - 1; j >= 0 ; j--) {
 395                         if (!tcrypt_cipher[i].cipher[j].name)
 396                                 continue;
 397                         r = decrypt_hdr_one(&tcrypt_cipher[i].cipher[j],
 398                                             tcrypt_cipher[i].mode, key, &hdr2);
 399                         if (r < 0)
 400                                 break;
 401                 }
 402
 403                 if (r < 0) {
 404                         log_dbg("TCRYPT:   returned error %d, skipped.", r);
 405                         if (r == -ENOTSUP)
 406                                 break;
 407                         r = -ENOENT;
 408                         continue;
 409                 }
 410
 411                 if (!strncmp(hdr2.d.magic, TCRYPT_HDR_MAGIC, TCRYPT_HDR_MAGIC_LEN)) {
 412                         log_dbg("TCRYPT: Signature magic detected.");
 413                         memcpy(&hdr->e, &hdr2.e, TCRYPT_HDR_LEN);
 414                         memset(&hdr2.e, 0, TCRYPT_HDR_LEN);
 415                         r = i;
 416                         break;
 417                 }
 418                 r = -EPERM;
 419         }
 420
 421         return r;
 422 }
 423
 424 static int pool_keyfile(struct crypt_device *cd,
 425                         unsigned char pool[TCRYPT_KEY_POOL_LEN],
 426                         const char *keyfile)
 427 {
 428         unsigned char data[TCRYPT_KEYFILE_LEN];
 429         int i, j, fd, data_size;
 430         uint32_t crc;
 431         unsigned char *crc_c = (unsigned char*)&crc;
 432
 433         log_dbg("TCRYPT: using keyfile %s.", keyfile);
 434
 435         fd = open(keyfile, O_RDONLY);
 436         if (fd < 0) {
 437                 log_err(cd, _("Failed to open key file.\n"));
 438                 return -EIO;
 439         }
 440
 441         /* FIXME: add while */
 442         data_size = read(fd, data, TCRYPT_KEYFILE_LEN);
 443         close(fd);
 444         if (data_size < 0) {
 445                 log_err(cd, _("Error reading keyfile %s.\n"), keyfile);
 446                 return -EIO;
 447         }
 448
 449         for (i = 0, j = 0, crc = ~0U; i < data_size; i++) {
 450                 crc = crypt_crc32(crc, &data[i], 1);
 451                 pool[j++] += crc_c[3];
 452                 pool[j++] += crc_c[2];
 453                 pool[j++] += crc_c[1];
 454                 pool[j++] += crc_c[0];
 455                 j %= TCRYPT_KEY_POOL_LEN;
 456         }
 457
 458         crc = 0;
 459         memset(data, 0, TCRYPT_KEYFILE_LEN);
 460
 461         return 0;
 462 }
 463
 464 static int TCRYPT_init_hdr(struct crypt_device *cd,
 465                            struct tcrypt_phdr *hdr,
 466                            struct crypt_params_tcrypt *params)
 467 {
 468         unsigned char pwd[TCRYPT_KEY_POOL_LEN] = {};
 469         size_t passphrase_size;
 470         char *key;
 471         int r = -EINVAL, i, legacy_modes, skipped = 0;
 472
 473         if (posix_memalign((void*)&key, crypt_getpagesize(), TCRYPT_HDR_KEY_LEN))
 474                 return -ENOMEM;
 475
 476         if (params->keyfiles_count)
 477                 passphrase_size = TCRYPT_KEY_POOL_LEN;
 478         else
 479                 passphrase_size = params->passphrase_size;
 480
 481         /* Calculate pool content from keyfiles */
 482         for (i = 0; i < params->keyfiles_count; i++) {
 483                 r = pool_keyfile(cd, pwd, params->keyfiles[i]);
 484                 if (r < 0)
 485                         goto out;
 486         }
 487
 488         /* If provided password, combine it with pool */
 489         for (i = 0; i < params->passphrase_size; i++)
 490                 pwd[i] += params->passphrase[i];
 491
 492         legacy_modes = params->flags & CRYPT_TCRYPT_LEGACY_MODES ? 1 : 0;
 493         for (i = 0; tcrypt_kdf[i].name; i++) {
 494                 if (!legacy_modes && tcrypt_kdf[i].legacy)
 495                         continue;
 496                 /* Derive header key */
 497                 log_dbg("TCRYPT: trying KDF: %s-%s-%d.",
 498                         tcrypt_kdf[i].name, tcrypt_kdf[i].hash, tcrypt_kdf[i].iterations);
 499                 r = crypt_pbkdf(tcrypt_kdf[i].name, tcrypt_kdf[i].hash,
 500                                 (char*)pwd, passphrase_size,
 501                                 hdr->salt, TCRYPT_HDR_SALT_LEN,
 502                                 key, TCRYPT_HDR_KEY_LEN,
 503                                 tcrypt_kdf[i].iterations);
 504                 if (r < 0)
 505                         break;
 506
 507                 /* Decrypt header */
 508                 r = decrypt_hdr(cd, hdr, key, legacy_modes);
 509                 if (r == -ENOENT) {
 510                         skipped++;
 511                         continue;
 512                 }
 513                 if (r != -EPERM)
 514                         break;
 515         }
 516
 517         if ((skipped && skipped == i) || r == -ENOTSUP)
 518                 log_err(cd, _("Required kernel crypto interface not available.\n"
 519                               "Ensure you have algif_skcipher kernel module loaded.\n"));
 520         if (r < 0)
 521                 goto out;
 522
 523         r = hdr_from_disk(hdr, params, i, r);
 524         if (!r) {
 525                 log_dbg("TCRYPT: Header version: %d, req. %d, sector %d"
 526                         ", mk_offset %" PRIu64 ", hidden_size %" PRIu64
 527                         ", volume size %" PRIu64, (int)hdr->d.version,
 528                         (int)hdr->d.version_tc, (int)hdr->d.sector_size,
 529                         hdr->d.mk_offset, hdr->d.hidden_volume_size, hdr->d.volume_size);
 530                 log_dbg("TCRYPT: Header cipher %s-%s, key size %d",
 531                         params->cipher, params->mode, params->key_size);
 532         }
 533 out:
 534         memset(pwd, 0, TCRYPT_KEY_POOL_LEN);
 535         if (key)
 536                 memset(key, 0, TCRYPT_HDR_KEY_LEN);
 537         free(key);
 538         return r;
 539 }
 540
 541 int TCRYPT_read_phdr(struct crypt_device *cd,
 542                      struct tcrypt_phdr *hdr,
 543                      struct crypt_params_tcrypt *params)
 544 {
 545         struct device *device = crypt_metadata_device(cd);
 546         ssize_t hdr_size = sizeof(struct tcrypt_phdr);
 547         int devfd = 0, r, bs;
 548
 549         assert(sizeof(struct tcrypt_phdr) == 512);
 550
 551         log_dbg("Reading TCRYPT header of size %d bytes from device %s.",
 552                 hdr_size, device_path(device));
 553
 554         bs = device_block_size(device);
 555         if (bs < 0)
 556                 return bs;
 557
 558         devfd = open(device_path(device), O_RDONLY | O_DIRECT);
 559         if (devfd == -1) {
 560                 log_err(cd, _("Cannot open device %s.\n"), device_path(device));
 561                 return -EINVAL;
 562         }
 563
 564         r = -EIO;
 565         if (params->flags & CRYPT_TCRYPT_HIDDEN_HEADER) {
 566                 if (params->flags & CRYPT_TCRYPT_BACKUP_HEADER) {
 567                         if (lseek(devfd, TCRYPT_HDR_HIDDEN_OFFSET_BCK, SEEK_END) >= 0 &&
 568                             read_blockwise(devfd, bs, hdr, hdr_size) == hdr_size)
 569                                 r = TCRYPT_init_hdr(cd, hdr, params);
 570                 } else {
 571                         if (lseek(devfd, TCRYPT_HDR_HIDDEN_OFFSET, SEEK_SET) >= 0 &&
 572                             read_blockwise(devfd, bs, hdr, hdr_size) == hdr_size)
 573                                 r = TCRYPT_init_hdr(cd, hdr, params);
 574                         if (r &&
 575                             lseek(devfd, TCRYPT_HDR_HIDDEN_OFFSET_OLD, SEEK_END) >= 0 &&
 576                             read_blockwise(devfd, bs, hdr, hdr_size) == hdr_size)
 577                                 r = TCRYPT_init_hdr(cd, hdr, params);
 578                 }
 579         } else if (params->flags & CRYPT_TCRYPT_BACKUP_HEADER) {
 580                 if (lseek(devfd, TCRYPT_HDR_OFFSET_BCK, SEEK_END) >= 0 &&
 581                             read_blockwise(devfd, bs, hdr, hdr_size) == hdr_size)
 582                         r = TCRYPT_init_hdr(cd, hdr, params);
 583         } else if (read_blockwise(devfd, bs, hdr, hdr_size) == hdr_size)
 584                 r = TCRYPT_init_hdr(cd, hdr, params);
 585
 586         close(devfd);
 587         return r;
 588 }
 589
 590 static struct tcrypt_algs *get_algs(struct crypt_params_tcrypt *params)
 591 {
 592         int i;
 593
 594         if (!params->cipher || !params->mode)
 595                 return NULL;
 596
 597         for (i = 0; tcrypt_cipher[i].chain_count; i++)
 598                 if (!strcmp(tcrypt_cipher[i].long_name, params->cipher) &&
 599                     !strcmp(tcrypt_cipher[i].mode, params->mode))
 600                     return &tcrypt_cipher[i];
 601
 602         return NULL;
 603 }
 604
 605 int TCRYPT_activate(struct crypt_device *cd,
 606                      const char *name,
 607                      struct tcrypt_phdr *hdr,
 608                      struct crypt_params_tcrypt *params,
 609                      uint32_t flags)
 610 {
 611         char cipher[MAX_CIPHER_LEN], dm_name[PATH_MAX], dm_dev_name[PATH_MAX];
 612         struct device *device = NULL;
 613         int i, r;
 614         struct tcrypt_algs *algs;
 615         struct crypt_dm_active_device dmd = {
 616                 .target = DM_CRYPT,
 617                 .size   = 0,
 618                 .data_device = crypt_data_device(cd),
 619                 .u.crypt  = {
 620                         .cipher = cipher,
 621                         .offset = crypt_get_data_offset(cd),
 622                         .iv_offset = crypt_get_iv_offset(cd),
 623                 }
 624         };
 625
 626         if (!hdr->d.version) {
 627                 log_dbg("TCRYPT: this function is not supported without encrypted header load.");
 628                 return -ENOTSUP;
 629         }
 630
 631         if (hdr->d.sector_size && hdr->d.sector_size != SECTOR_SIZE) {
 632                 log_err(cd, _("Activation is not supported for %d sector size.\n"),
 633                         hdr->d.sector_size);
 634                 return -ENOTSUP;
 635         }
 636
 637         if (strstr(params->mode, "-tcrypt")) {
 638                 log_err(cd, _("Kernel doesn't support activation for this TCRYPT legacy mode.\n"));
 639                 return -ENOTSUP;
 640         }
 641
 642         algs = get_algs(params);
 643         if (!algs)
 644                 return -EINVAL;
 645
 646         if (params->flags & CRYPT_TCRYPT_HIDDEN_HEADER)
 647                 dmd.size = hdr->d.hidden_volume_size / hdr->d.sector_size;
 648         else
 649                 dmd.size = hdr->d.volume_size / hdr->d.sector_size;
 650
 651         r = device_block_adjust(cd, dmd.data_device, DEV_EXCL,
 652                                 dmd.u.crypt.offset, &dmd.size, &dmd.flags);
 653         if (r)
 654                 return r;
 655
 656         /* Frome here, key size for every cipher must be the same */
 657         dmd.u.crypt.vk = crypt_alloc_volume_key(algs->cipher[0].key_size, NULL);
 658         if (!dmd.u.crypt.vk)
 659                 return -ENOMEM;
 660
 661         for (i = algs->chain_count - 1; i >= 0; i--) {
 662                 if (i == 0) {
 663                         strncpy(dm_name, name, sizeof(dm_name));
 664                         dmd.flags = flags;
 665                 } else {
 666                         snprintf(dm_name, sizeof(dm_name), "%s_%d", name, i);
 667                         dmd.flags = flags | CRYPT_ACTIVATE_PRIVATE;
 668                 }
 669
 670                 snprintf(cipher, sizeof(cipher), "%s-%s",
 671                          algs->cipher[i].name, algs->mode);
 672
 673                 copy_key(&algs->cipher[i], algs->mode, dmd.u.crypt.vk->key, hdr->d.keys);
 674
 675                 if ((algs->chain_count - 1) != i) {
 676                         snprintf(dm_dev_name, sizeof(dm_dev_name), "%s/%s_%d",
 677                                  dm_get_dir(), name, i + 1);
 678                         r = device_alloc(&device, dm_dev_name);
 679                         if (r)
 680                                 break;
 681                         dmd.data_device = device;
 682                         dmd.u.crypt.offset = 0;
 683                 }
 684
 685                 log_dbg("Trying to activate TCRYPT device %s using cipher %s.",
 686                         dm_name, dmd.u.crypt.cipher);
 687                 r = dm_create_device(cd, dm_name, CRYPT_TCRYPT, &dmd, 0);
 688
 689                 device_free(device);
 690                 device = NULL;
 691
 692                 if (r)
 693                         break;
 694         }
 695
 696         if (!r && !(dm_flags() & DM_PLAIN64_SUPPORTED)) {
 697                 log_err(cd, _("Kernel doesn't support plain64 IV.\n"));
 698                 r = -ENOTSUP;
 699         }
 700
 701         crypt_free_volume_key(dmd.u.crypt.vk);
 702         return r;
 703 }
 704
 705 static int remove_one(struct crypt_device *cd, const char *name,
 706                       const char *base_uuid, int index)
 707 {
 708         struct crypt_dm_active_device dmd = {};
 709         char dm_name[PATH_MAX];
 710         int r;
 711
 712         if (snprintf(dm_name, sizeof(dm_name), "%s_%d", name, index) < 0)
 713                 return -ENOMEM;
 714
 715         r = dm_status_device(cd, dm_name);
 716         if (r < 0)
 717                 return r;
 718
 719         r = dm_query_device(cd, dm_name, DM_ACTIVE_UUID, &dmd);
 720         if (!r && !strncmp(dmd.uuid, base_uuid, strlen(base_uuid)))
 721                 r = dm_remove_device(cd, dm_name, 0, 0);
 722
 723         free(CONST_CAST(void*)dmd.uuid);
 724         return r;
 725 }
 726
 727 int TCRYPT_deactivate(struct crypt_device *cd, const char *name)
 728 {
 729         struct crypt_dm_active_device dmd = {};
 730         int r;
 731
 732         r = dm_query_device(cd, name, DM_ACTIVE_UUID, &dmd);
 733         if (r < 0)
 734                 return r;
 735         if (!dmd.uuid)
 736                 return -EINVAL;
 737
 738         r = dm_remove_device(cd, name, 0, 0);
 739         if (r < 0)
 740                 goto out;
 741
 742         r = remove_one(cd, name, dmd.uuid, 1);
 743         if (r < 0)
 744                 goto out;
 745
 746         r = remove_one(cd, name, dmd.uuid, 2);
 747         if (r < 0)
 748                 goto out;
 749 out:
 750         free(CONST_CAST(void*)dmd.uuid);
 751         return (r == -ENODEV) ? 0 : r;
 752 }
 753
 754 static int status_one(struct crypt_device *cd, const char *name,
 755                       const char *base_uuid, int index,
 756                       size_t *key_size, char *cipher, uint64_t *data_offset,
 757                       struct device **device)
 758 {
 759         struct crypt_dm_active_device dmd = {};
 760         char dm_name[PATH_MAX], *c;
 761         int r;
 762
 763         if (snprintf(dm_name, sizeof(dm_name), "%s_%d", name, index) < 0)
 764                 return -ENOMEM;
 765
 766         r = dm_status_device(cd, dm_name);
 767         if (r < 0)
 768                 return r;
 769
 770         r = dm_query_device(cd, dm_name, DM_ACTIVE_DEVICE |
 771                                           DM_ACTIVE_UUID |
 772                                           DM_ACTIVE_CRYPT_CIPHER |
 773                                           DM_ACTIVE_CRYPT_KEYSIZE, &dmd);
 774         if (r > 0)
 775                 r = 0;
 776         if (!r && !strncmp(dmd.uuid, base_uuid, strlen(base_uuid))) {
 777                 if ((c = strchr(dmd.u.crypt.cipher, '-')))
 778                         *c = '\0';
 779                 strcat(cipher, "-");
 780                 strncat(cipher, dmd.u.crypt.cipher, MAX_CIPHER_LEN);
 781                 *key_size += dmd.u.crypt.vk->keylength;
 782                 *data_offset = dmd.u.crypt.offset * SECTOR_SIZE;
 783                 device_free(*device);
 784                 *device = dmd.data_device;
 785         } else {
 786                 device_free(dmd.data_device);
 787                 r = -ENODEV;
 788         }
 789
 790         free(CONST_CAST(void*)dmd.uuid);
 791         free(CONST_CAST(void*)dmd.u.crypt.cipher);
 792         crypt_free_volume_key(dmd.u.crypt.vk);
 793         return r;
 794 }
 795
 796 int TCRYPT_init_by_name(struct crypt_device *cd, const char *name,
 797                         const struct crypt_dm_active_device *dmd,
 798                         struct device **device,
 799                         struct crypt_params_tcrypt *tcrypt_params,
 800                         struct tcrypt_phdr *tcrypt_hdr)
 801 {
 802         char cipher[MAX_CIPHER_LEN * 4], *mode;
 803
 804         memset(tcrypt_params, 0, sizeof(*tcrypt_params));
 805         memset(tcrypt_hdr, 0, sizeof(*tcrypt_hdr));
 806         tcrypt_hdr->d.sector_size = SECTOR_SIZE;
 807         tcrypt_hdr->d.mk_offset = dmd->u.crypt.offset * SECTOR_SIZE;
 808
 809         strncpy(cipher, dmd->u.crypt.cipher, MAX_CIPHER_LEN);
 810
 811         if ((mode = strchr(cipher, '-'))) {
 812                 *mode = '\0';
 813                 tcrypt_params->mode = strdup(++mode);
 814         }
 815         tcrypt_params->key_size = dmd->u.crypt.vk->keylength;
 816
 817         if (!status_one(cd, name, dmd->uuid, 1, &tcrypt_params->key_size,
 818                         cipher, &tcrypt_hdr->d.mk_offset, device))
 819                 status_one(cd, name, dmd->uuid, 2, &tcrypt_params->key_size,
 820                            cipher, &tcrypt_hdr->d.mk_offset, device);
 821
 822         tcrypt_params->cipher = strdup(cipher);
 823         return 0;
 824 }
 825
 826 uint64_t TCRYPT_get_data_offset(struct crypt_device *cd,
 827                                  struct tcrypt_phdr *hdr,
 828                                  struct crypt_params_tcrypt *params)
 829 {
 830         uint64_t size;
 831
 832         if (params->mode && !strncmp(params->mode, "xts", 3)) {
 833                 if (hdr->d.version < 3)
 834                         return 1;
 835
 836                 if (params->flags & CRYPT_TCRYPT_HIDDEN_HEADER) {
 837                         if (hdr->d.version > 3)
 838                                 return (hdr->d.mk_offset / hdr->d.sector_size);
 839                         if (device_size(crypt_metadata_device(cd), &size) < 0)
 840                                 return 0;
 841                         return (size - hdr->d.hidden_volume_size +
 842                                 (TCRYPT_HDR_HIDDEN_OFFSET_OLD)) / hdr->d.sector_size;
 843                 }
 844                 return (hdr->d.mk_offset / hdr->d.sector_size);
 845         }
 846
 847         if (params->flags & CRYPT_TCRYPT_HIDDEN_HEADER) {
 848                 if (device_size(crypt_metadata_device(cd), &size) < 0)
 849                         return 0;
 850                 return (size - hdr->d.hidden_volume_size +
 851                         (TCRYPT_HDR_HIDDEN_OFFSET_OLD)) / hdr->d.sector_size;
 852         }
 853
 854         // FIXME: system vol.
 855         return hdr->d.mk_offset / hdr->d.sector_size;
 856 }
 857
 858 uint64_t TCRYPT_get_iv_offset(struct crypt_device *cd,
 859                               struct tcrypt_phdr *hdr,
 860                               struct crypt_params_tcrypt *params
 861 )
 862 {
 863         if (params->mode && !strncmp(params->mode, "xts", 3))
 864                 return TCRYPT_get_data_offset(cd, hdr, params);
 865         else if (params->mode && !strncmp(params->mode, "lrw", 3))
 866                 return 0;
 867
 868         return hdr->d.mk_offset / hdr->d.sector_size;
 869 }
 870
 871 int TCRYPT_get_volume_key(struct crypt_device *cd,
 872                           struct tcrypt_phdr *hdr,
 873                           struct crypt_params_tcrypt *params,
 874                           struct volume_key **vk)
 875 {
 876         struct tcrypt_algs *algs;
 877         int i, key_index;
 878
 879         if (!hdr->d.version) {
 880                 log_dbg("TCRYPT: this function is not supported without encrypted header load.");
 881                 return -ENOTSUP;
 882         }
 883
 884         algs = get_algs(params);
 885         if (!algs)
 886                 return -EINVAL;
 887
 888         *vk = crypt_alloc_volume_key(params->key_size, NULL);
 889         if (!*vk)
 890                 return -ENOMEM;
 891
 892         for (i = 0, key_index = 0; i < algs->chain_count; i++) {
 893                 copy_key(&algs->cipher[i], algs->mode,
 894                          &(*vk)->key[key_index], hdr->d.keys);
 895                 key_index += algs->cipher[i].key_size;
 896         }
 897
 898         return 0;
 899 }
 900
 901 int TCRYPT_dump(struct crypt_device *cd,
 902                 struct tcrypt_phdr *hdr,
 903                 struct crypt_params_tcrypt *params)
 904 {
 905         log_std(cd, "TCRYPT header information for %s\n",
 906                 device_path(crypt_metadata_device(cd)));
 907         if (hdr->d.version) {
 908                 log_std(cd, "Version:       \t%d\n", hdr->d.version);
 909                 log_std(cd, "Driver req.:\t%d\n", hdr->d.version_tc);
 910
 911                 log_std(cd, "Sector size:\t%" PRIu32 "\n", hdr->d.sector_size);
 912                 log_std(cd, "MK offset:\t%" PRIu64 "\n", hdr->d.mk_offset);
 913                 log_std(cd, "PBKDF2 hash:\t%s\n", params->hash_name);
 914         }
 915         log_std(cd, "Cipher chain:\t%s\n", params->cipher);
 916         log_std(cd, "Cipher mode:\t%s\n", params->mode);
 917         log_std(cd, "MK bits:       \t%d\n", params->key_size * 8);
 918         return 0;
 919 }