1 /** 2 * eCryptfs: Linux filesystem encryption layer 3 * In-kernel key management code. Includes functions to parse and 4 * write authentication token-related packets with the underlying 5 * file. 6 * 7 * Copyright (C) 2004-2006 International Business Machines Corp. 8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> 9 * Michael C. Thompson <mcthomps@us.ibm.com> 10 * Trevor S. Highland <trevor.highland@gmail.com> 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License as 14 * published by the Free Software Foundation; either version 2 of the 15 * License, or (at your option) any later version. 16 * 17 * This program is distributed in the hope that it will be useful, but 18 * WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20 * General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License 23 * along with this program; if not, write to the Free Software 24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 25 * 02111-1307, USA. 26 */ 27 28 #include <linux/string.h> 29 #include <linux/syscalls.h> 30 #include <linux/pagemap.h> 31 #include <linux/key.h> 32 #include <linux/random.h> 33 #include <linux/crypto.h> 34 #include <linux/scatterlist.h> 35 #include <linux/slab.h> 36 #include "ecryptfs_kernel.h" 37 38 /** 39 * request_key returned an error instead of a valid key address; 40 * determine the type of error, make appropriate log entries, and 41 * return an error code. 42 */ 43 static int process_request_key_err(long err_code) 44 { 45 int rc = 0; 46 47 switch (err_code) { 48 case -ENOKEY: 49 ecryptfs_printk(KERN_WARNING, "No key\n"); 50 rc = -ENOENT; 51 break; 52 case -EKEYEXPIRED: 53 ecryptfs_printk(KERN_WARNING, "Key expired\n"); 54 rc = -ETIME; 55 break; 56 case -EKEYREVOKED: 57 ecryptfs_printk(KERN_WARNING, "Key revoked\n"); 58 rc = -EINVAL; 59 break; 60 default: 61 ecryptfs_printk(KERN_WARNING, "Unknown error code: " 62 "[0x%.16lx]\n", err_code); 63 rc = -EINVAL; 64 } 65 return rc; 66 } 67 68 static int process_find_global_auth_tok_for_sig_err(int err_code) 69 { 70 int rc = err_code; 71 72 switch (err_code) { 73 case -ENOENT: 74 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n"); 75 break; 76 case -EINVAL: 77 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n"); 78 break; 79 default: 80 rc = process_request_key_err(err_code); 81 break; 82 } 83 return rc; 84 } 85 86 /** 87 * ecryptfs_parse_packet_length 88 * @data: Pointer to memory containing length at offset 89 * @size: This function writes the decoded size to this memory 90 * address; zero on error 91 * @length_size: The number of bytes occupied by the encoded length 92 * 93 * Returns zero on success; non-zero on error 94 */ 95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, 96 size_t *length_size) 97 { 98 int rc = 0; 99 100 (*length_size) = 0; 101 (*size) = 0; 102 if (data[0] < 192) { 103 /* One-byte length */ 104 (*size) = (unsigned char)data[0]; 105 (*length_size) = 1; 106 } else if (data[0] < 224) { 107 /* Two-byte length */ 108 (*size) = (((unsigned char)(data[0]) - 192) * 256); 109 (*size) += ((unsigned char)(data[1]) + 192); 110 (*length_size) = 2; 111 } else if (data[0] == 255) { 112 /* Five-byte length; we're not supposed to see this */ 113 ecryptfs_printk(KERN_ERR, "Five-byte packet length not " 114 "supported\n"); 115 rc = -EINVAL; 116 goto out; 117 } else { 118 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n"); 119 rc = -EINVAL; 120 goto out; 121 } 122 out: 123 return rc; 124 } 125 126 /** 127 * ecryptfs_write_packet_length 128 * @dest: The byte array target into which to write the length. Must 129 * have at least 5 bytes allocated. 130 * @size: The length to write. 131 * @packet_size_length: The number of bytes used to encode the packet 132 * length is written to this address. 133 * 134 * Returns zero on success; non-zero on error. 135 */ 136 int ecryptfs_write_packet_length(char *dest, size_t size, 137 size_t *packet_size_length) 138 { 139 int rc = 0; 140 141 if (size < 192) { 142 dest[0] = size; 143 (*packet_size_length) = 1; 144 } else if (size < 65536) { 145 dest[0] = (((size - 192) / 256) + 192); 146 dest[1] = ((size - 192) % 256); 147 (*packet_size_length) = 2; 148 } else { 149 rc = -EINVAL; 150 ecryptfs_printk(KERN_WARNING, 151 "Unsupported packet size: [%zd]\n", size); 152 } 153 return rc; 154 } 155 156 static int 157 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key, 158 char **packet, size_t *packet_len) 159 { 160 size_t i = 0; 161 size_t data_len; 162 size_t packet_size_len; 163 char *message; 164 int rc; 165 166 /* 167 * ***** TAG 64 Packet Format ***** 168 * | Content Type | 1 byte | 169 * | Key Identifier Size | 1 or 2 bytes | 170 * | Key Identifier | arbitrary | 171 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 172 * | Encrypted File Encryption Key | arbitrary | 173 */ 174 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX 175 + session_key->encrypted_key_size); 176 *packet = kmalloc(data_len, GFP_KERNEL); 177 message = *packet; 178 if (!message) { 179 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 180 rc = -ENOMEM; 181 goto out; 182 } 183 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE; 184 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 185 &packet_size_len); 186 if (rc) { 187 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 188 "header; cannot generate packet length\n"); 189 goto out; 190 } 191 i += packet_size_len; 192 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 193 i += ECRYPTFS_SIG_SIZE_HEX; 194 rc = ecryptfs_write_packet_length(&message[i], 195 session_key->encrypted_key_size, 196 &packet_size_len); 197 if (rc) { 198 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 199 "header; cannot generate packet length\n"); 200 goto out; 201 } 202 i += packet_size_len; 203 memcpy(&message[i], session_key->encrypted_key, 204 session_key->encrypted_key_size); 205 i += session_key->encrypted_key_size; 206 *packet_len = i; 207 out: 208 return rc; 209 } 210 211 static int 212 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code, 213 struct ecryptfs_message *msg) 214 { 215 size_t i = 0; 216 char *data; 217 size_t data_len; 218 size_t m_size; 219 size_t message_len; 220 u16 checksum = 0; 221 u16 expected_checksum = 0; 222 int rc; 223 224 /* 225 * ***** TAG 65 Packet Format ***** 226 * | Content Type | 1 byte | 227 * | Status Indicator | 1 byte | 228 * | File Encryption Key Size | 1 or 2 bytes | 229 * | File Encryption Key | arbitrary | 230 */ 231 message_len = msg->data_len; 232 data = msg->data; 233 if (message_len < 4) { 234 rc = -EIO; 235 goto out; 236 } 237 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) { 238 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n"); 239 rc = -EIO; 240 goto out; 241 } 242 if (data[i++]) { 243 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value " 244 "[%d]\n", data[i-1]); 245 rc = -EIO; 246 goto out; 247 } 248 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len); 249 if (rc) { 250 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 251 "rc = [%d]\n", rc); 252 goto out; 253 } 254 i += data_len; 255 if (message_len < (i + m_size)) { 256 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd " 257 "is shorter than expected\n"); 258 rc = -EIO; 259 goto out; 260 } 261 if (m_size < 3) { 262 ecryptfs_printk(KERN_ERR, 263 "The decrypted key is not long enough to " 264 "include a cipher code and checksum\n"); 265 rc = -EIO; 266 goto out; 267 } 268 *cipher_code = data[i++]; 269 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */ 270 session_key->decrypted_key_size = m_size - 3; 271 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) { 272 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than " 273 "the maximum key size [%d]\n", 274 session_key->decrypted_key_size, 275 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 276 rc = -EIO; 277 goto out; 278 } 279 memcpy(session_key->decrypted_key, &data[i], 280 session_key->decrypted_key_size); 281 i += session_key->decrypted_key_size; 282 expected_checksum += (unsigned char)(data[i++]) << 8; 283 expected_checksum += (unsigned char)(data[i++]); 284 for (i = 0; i < session_key->decrypted_key_size; i++) 285 checksum += session_key->decrypted_key[i]; 286 if (expected_checksum != checksum) { 287 ecryptfs_printk(KERN_ERR, "Invalid checksum for file " 288 "encryption key; expected [%x]; calculated " 289 "[%x]\n", expected_checksum, checksum); 290 rc = -EIO; 291 } 292 out: 293 return rc; 294 } 295 296 297 static int 298 write_tag_66_packet(char *signature, u8 cipher_code, 299 struct ecryptfs_crypt_stat *crypt_stat, char **packet, 300 size_t *packet_len) 301 { 302 size_t i = 0; 303 size_t j; 304 size_t data_len; 305 size_t checksum = 0; 306 size_t packet_size_len; 307 char *message; 308 int rc; 309 310 /* 311 * ***** TAG 66 Packet Format ***** 312 * | Content Type | 1 byte | 313 * | Key Identifier Size | 1 or 2 bytes | 314 * | Key Identifier | arbitrary | 315 * | File Encryption Key Size | 1 or 2 bytes | 316 * | File Encryption Key | arbitrary | 317 */ 318 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); 319 *packet = kmalloc(data_len, GFP_KERNEL); 320 message = *packet; 321 if (!message) { 322 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 323 rc = -ENOMEM; 324 goto out; 325 } 326 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; 327 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 328 &packet_size_len); 329 if (rc) { 330 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 331 "header; cannot generate packet length\n"); 332 goto out; 333 } 334 i += packet_size_len; 335 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 336 i += ECRYPTFS_SIG_SIZE_HEX; 337 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */ 338 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, 339 &packet_size_len); 340 if (rc) { 341 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 342 "header; cannot generate packet length\n"); 343 goto out; 344 } 345 i += packet_size_len; 346 message[i++] = cipher_code; 347 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); 348 i += crypt_stat->key_size; 349 for (j = 0; j < crypt_stat->key_size; j++) 350 checksum += crypt_stat->key[j]; 351 message[i++] = (checksum / 256) % 256; 352 message[i++] = (checksum % 256); 353 *packet_len = i; 354 out: 355 return rc; 356 } 357 358 static int 359 parse_tag_67_packet(struct ecryptfs_key_record *key_rec, 360 struct ecryptfs_message *msg) 361 { 362 size_t i = 0; 363 char *data; 364 size_t data_len; 365 size_t message_len; 366 int rc; 367 368 /* 369 * ***** TAG 65 Packet Format ***** 370 * | Content Type | 1 byte | 371 * | Status Indicator | 1 byte | 372 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 373 * | Encrypted File Encryption Key | arbitrary | 374 */ 375 message_len = msg->data_len; 376 data = msg->data; 377 /* verify that everything through the encrypted FEK size is present */ 378 if (message_len < 4) { 379 rc = -EIO; 380 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " 381 "message length is [%d]\n", __func__, message_len, 4); 382 goto out; 383 } 384 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { 385 rc = -EIO; 386 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", 387 __func__); 388 goto out; 389 } 390 if (data[i++]) { 391 rc = -EIO; 392 printk(KERN_ERR "%s: Status indicator has non zero " 393 "value [%d]\n", __func__, data[i-1]); 394 395 goto out; 396 } 397 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, 398 &data_len); 399 if (rc) { 400 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 401 "rc = [%d]\n", rc); 402 goto out; 403 } 404 i += data_len; 405 if (message_len < (i + key_rec->enc_key_size)) { 406 rc = -EIO; 407 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", 408 __func__, message_len, (i + key_rec->enc_key_size)); 409 goto out; 410 } 411 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 412 rc = -EIO; 413 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " 414 "the maximum key size [%d]\n", __func__, 415 key_rec->enc_key_size, 416 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 417 goto out; 418 } 419 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); 420 out: 421 return rc; 422 } 423 424 /** 425 * ecryptfs_verify_version 426 * @version: The version number to confirm 427 * 428 * Returns zero on good version; non-zero otherwise 429 */ 430 static int ecryptfs_verify_version(u16 version) 431 { 432 int rc = 0; 433 unsigned char major; 434 unsigned char minor; 435 436 major = ((version >> 8) & 0xFF); 437 minor = (version & 0xFF); 438 if (major != ECRYPTFS_VERSION_MAJOR) { 439 ecryptfs_printk(KERN_ERR, "Major version number mismatch. " 440 "Expected [%d]; got [%d]\n", 441 ECRYPTFS_VERSION_MAJOR, major); 442 rc = -EINVAL; 443 goto out; 444 } 445 if (minor != ECRYPTFS_VERSION_MINOR) { 446 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " 447 "Expected [%d]; got [%d]\n", 448 ECRYPTFS_VERSION_MINOR, minor); 449 rc = -EINVAL; 450 goto out; 451 } 452 out: 453 return rc; 454 } 455 456 /** 457 * ecryptfs_verify_auth_tok_from_key 458 * @auth_tok_key: key containing the authentication token 459 * @auth_tok: authentication token 460 * 461 * Returns zero on valid auth tok; -EINVAL otherwise 462 */ 463 static int 464 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, 465 struct ecryptfs_auth_tok **auth_tok) 466 { 467 int rc = 0; 468 469 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); 470 if (ecryptfs_verify_version((*auth_tok)->version)) { 471 printk(KERN_ERR "Data structure version mismatch. Userspace " 472 "tools must match eCryptfs kernel module with major " 473 "version [%d] and minor version [%d]\n", 474 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); 475 rc = -EINVAL; 476 goto out; 477 } 478 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD 479 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { 480 printk(KERN_ERR "Invalid auth_tok structure " 481 "returned from key query\n"); 482 rc = -EINVAL; 483 goto out; 484 } 485 out: 486 return rc; 487 } 488 489 static int 490 ecryptfs_find_global_auth_tok_for_sig( 491 struct key **auth_tok_key, 492 struct ecryptfs_auth_tok **auth_tok, 493 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) 494 { 495 struct ecryptfs_global_auth_tok *walker; 496 int rc = 0; 497 498 (*auth_tok_key) = NULL; 499 (*auth_tok) = NULL; 500 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 501 list_for_each_entry(walker, 502 &mount_crypt_stat->global_auth_tok_list, 503 mount_crypt_stat_list) { 504 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) 505 continue; 506 507 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { 508 rc = -EINVAL; 509 goto out; 510 } 511 512 rc = key_validate(walker->global_auth_tok_key); 513 if (rc) { 514 if (rc == -EKEYEXPIRED) 515 goto out; 516 goto out_invalid_auth_tok; 517 } 518 519 down_write(&(walker->global_auth_tok_key->sem)); 520 rc = ecryptfs_verify_auth_tok_from_key( 521 walker->global_auth_tok_key, auth_tok); 522 if (rc) 523 goto out_invalid_auth_tok_unlock; 524 525 (*auth_tok_key) = walker->global_auth_tok_key; 526 key_get(*auth_tok_key); 527 goto out; 528 } 529 rc = -ENOENT; 530 goto out; 531 out_invalid_auth_tok_unlock: 532 up_write(&(walker->global_auth_tok_key->sem)); 533 out_invalid_auth_tok: 534 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); 535 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; 536 key_put(walker->global_auth_tok_key); 537 walker->global_auth_tok_key = NULL; 538 out: 539 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 540 return rc; 541 } 542 543 /** 544 * ecryptfs_find_auth_tok_for_sig 545 * @auth_tok: Set to the matching auth_tok; NULL if not found 546 * @crypt_stat: inode crypt_stat crypto context 547 * @sig: Sig of auth_tok to find 548 * 549 * For now, this function simply looks at the registered auth_tok's 550 * linked off the mount_crypt_stat, so all the auth_toks that can be 551 * used must be registered at mount time. This function could 552 * potentially try a lot harder to find auth_tok's (e.g., by calling 553 * out to ecryptfsd to dynamically retrieve an auth_tok object) so 554 * that static registration of auth_tok's will no longer be necessary. 555 * 556 * Returns zero on no error; non-zero on error 557 */ 558 static int 559 ecryptfs_find_auth_tok_for_sig( 560 struct key **auth_tok_key, 561 struct ecryptfs_auth_tok **auth_tok, 562 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 563 char *sig) 564 { 565 int rc = 0; 566 567 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, 568 mount_crypt_stat, sig); 569 if (rc == -ENOENT) { 570 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the 571 * mount_crypt_stat structure, we prevent to use auth toks that 572 * are not inserted through the ecryptfs_add_global_auth_tok 573 * function. 574 */ 575 if (mount_crypt_stat->flags 576 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) 577 return -EINVAL; 578 579 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, 580 sig); 581 } 582 return rc; 583 } 584 585 /** 586 * write_tag_70_packet can gobble a lot of stack space. We stuff most 587 * of the function's parameters in a kmalloc'd struct to help reduce 588 * eCryptfs' overall stack usage. 589 */ 590 struct ecryptfs_write_tag_70_packet_silly_stack { 591 u8 cipher_code; 592 size_t max_packet_size; 593 size_t packet_size_len; 594 size_t block_aligned_filename_size; 595 size_t block_size; 596 size_t i; 597 size_t j; 598 size_t num_rand_bytes; 599 struct mutex *tfm_mutex; 600 char *block_aligned_filename; 601 struct ecryptfs_auth_tok *auth_tok; 602 struct scatterlist src_sg[2]; 603 struct scatterlist dst_sg[2]; 604 struct blkcipher_desc desc; 605 char iv[ECRYPTFS_MAX_IV_BYTES]; 606 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 607 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 608 struct hash_desc hash_desc; 609 struct scatterlist hash_sg; 610 }; 611 612 /** 613 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK 614 * @filename: NULL-terminated filename string 615 * 616 * This is the simplest mechanism for achieving filename encryption in 617 * eCryptfs. It encrypts the given filename with the mount-wide 618 * filename encryption key (FNEK) and stores it in a packet to @dest, 619 * which the callee will encode and write directly into the dentry 620 * name. 621 */ 622 int 623 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, 624 size_t *packet_size, 625 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 626 char *filename, size_t filename_size) 627 { 628 struct ecryptfs_write_tag_70_packet_silly_stack *s; 629 struct key *auth_tok_key = NULL; 630 int rc = 0; 631 632 s = kmalloc(sizeof(*s), GFP_KERNEL); 633 if (!s) { 634 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 635 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 636 rc = -ENOMEM; 637 goto out; 638 } 639 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 640 (*packet_size) = 0; 641 rc = ecryptfs_find_auth_tok_for_sig( 642 &auth_tok_key, 643 &s->auth_tok, mount_crypt_stat, 644 mount_crypt_stat->global_default_fnek_sig); 645 if (rc) { 646 printk(KERN_ERR "%s: Error attempting to find auth tok for " 647 "fnek sig [%s]; rc = [%d]\n", __func__, 648 mount_crypt_stat->global_default_fnek_sig, rc); 649 goto out; 650 } 651 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 652 &s->desc.tfm, 653 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 654 if (unlikely(rc)) { 655 printk(KERN_ERR "Internal error whilst attempting to get " 656 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 657 mount_crypt_stat->global_default_fn_cipher_name, rc); 658 goto out; 659 } 660 mutex_lock(s->tfm_mutex); 661 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm); 662 /* Plus one for the \0 separator between the random prefix 663 * and the plaintext filename */ 664 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 665 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 666 if ((s->block_aligned_filename_size % s->block_size) != 0) { 667 s->num_rand_bytes += (s->block_size 668 - (s->block_aligned_filename_size 669 % s->block_size)); 670 s->block_aligned_filename_size = (s->num_rand_bytes 671 + filename_size); 672 } 673 /* Octet 0: Tag 70 identifier 674 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 675 * and block-aligned encrypted filename size) 676 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 677 * Octet N2-N3: Cipher identifier (1 octet) 678 * Octets N3-N4: Block-aligned encrypted filename 679 * - Consists of a minimum number of random characters, a \0 680 * separator, and then the filename */ 681 s->max_packet_size = (1 /* Tag 70 identifier */ 682 + 3 /* Max Tag 70 packet size */ 683 + ECRYPTFS_SIG_SIZE /* FNEK sig */ 684 + 1 /* Cipher identifier */ 685 + s->block_aligned_filename_size); 686 if (dest == NULL) { 687 (*packet_size) = s->max_packet_size; 688 goto out_unlock; 689 } 690 if (s->max_packet_size > (*remaining_bytes)) { 691 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 692 "[%zd] available\n", __func__, s->max_packet_size, 693 (*remaining_bytes)); 694 rc = -EINVAL; 695 goto out_unlock; 696 } 697 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 698 GFP_KERNEL); 699 if (!s->block_aligned_filename) { 700 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 701 "kzalloc [%zd] bytes\n", __func__, 702 s->block_aligned_filename_size); 703 rc = -ENOMEM; 704 goto out_unlock; 705 } 706 s->i = 0; 707 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 708 rc = ecryptfs_write_packet_length(&dest[s->i], 709 (ECRYPTFS_SIG_SIZE 710 + 1 /* Cipher code */ 711 + s->block_aligned_filename_size), 712 &s->packet_size_len); 713 if (rc) { 714 printk(KERN_ERR "%s: Error generating tag 70 packet " 715 "header; cannot generate packet length; rc = [%d]\n", 716 __func__, rc); 717 goto out_free_unlock; 718 } 719 s->i += s->packet_size_len; 720 ecryptfs_from_hex(&dest[s->i], 721 mount_crypt_stat->global_default_fnek_sig, 722 ECRYPTFS_SIG_SIZE); 723 s->i += ECRYPTFS_SIG_SIZE; 724 s->cipher_code = ecryptfs_code_for_cipher_string( 725 mount_crypt_stat->global_default_fn_cipher_name, 726 mount_crypt_stat->global_default_fn_cipher_key_bytes); 727 if (s->cipher_code == 0) { 728 printk(KERN_WARNING "%s: Unable to generate code for " 729 "cipher [%s] with key bytes [%zd]\n", __func__, 730 mount_crypt_stat->global_default_fn_cipher_name, 731 mount_crypt_stat->global_default_fn_cipher_key_bytes); 732 rc = -EINVAL; 733 goto out_free_unlock; 734 } 735 dest[s->i++] = s->cipher_code; 736 /* TODO: Support other key modules than passphrase for 737 * filename encryption */ 738 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 739 rc = -EOPNOTSUPP; 740 printk(KERN_INFO "%s: Filename encryption only supports " 741 "password tokens\n", __func__); 742 goto out_free_unlock; 743 } 744 sg_init_one( 745 &s->hash_sg, 746 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 747 s->auth_tok->token.password.session_key_encryption_key_bytes); 748 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 749 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0, 750 CRYPTO_ALG_ASYNC); 751 if (IS_ERR(s->hash_desc.tfm)) { 752 rc = PTR_ERR(s->hash_desc.tfm); 753 printk(KERN_ERR "%s: Error attempting to " 754 "allocate hash crypto context; rc = [%d]\n", 755 __func__, rc); 756 goto out_free_unlock; 757 } 758 rc = crypto_hash_init(&s->hash_desc); 759 if (rc) { 760 printk(KERN_ERR 761 "%s: Error initializing crypto hash; rc = [%d]\n", 762 __func__, rc); 763 goto out_release_free_unlock; 764 } 765 rc = crypto_hash_update( 766 &s->hash_desc, &s->hash_sg, 767 s->auth_tok->token.password.session_key_encryption_key_bytes); 768 if (rc) { 769 printk(KERN_ERR 770 "%s: Error updating crypto hash; rc = [%d]\n", 771 __func__, rc); 772 goto out_release_free_unlock; 773 } 774 rc = crypto_hash_final(&s->hash_desc, s->hash); 775 if (rc) { 776 printk(KERN_ERR 777 "%s: Error finalizing crypto hash; rc = [%d]\n", 778 __func__, rc); 779 goto out_release_free_unlock; 780 } 781 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 782 s->block_aligned_filename[s->j] = 783 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 784 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 785 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 786 sg_init_one(&s->hash_sg, (u8 *)s->hash, 787 ECRYPTFS_TAG_70_DIGEST_SIZE); 788 rc = crypto_hash_init(&s->hash_desc); 789 if (rc) { 790 printk(KERN_ERR 791 "%s: Error initializing crypto hash; " 792 "rc = [%d]\n", __func__, rc); 793 goto out_release_free_unlock; 794 } 795 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg, 796 ECRYPTFS_TAG_70_DIGEST_SIZE); 797 if (rc) { 798 printk(KERN_ERR 799 "%s: Error updating crypto hash; " 800 "rc = [%d]\n", __func__, rc); 801 goto out_release_free_unlock; 802 } 803 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash); 804 if (rc) { 805 printk(KERN_ERR 806 "%s: Error finalizing crypto hash; " 807 "rc = [%d]\n", __func__, rc); 808 goto out_release_free_unlock; 809 } 810 memcpy(s->hash, s->tmp_hash, 811 ECRYPTFS_TAG_70_DIGEST_SIZE); 812 } 813 if (s->block_aligned_filename[s->j] == '\0') 814 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 815 } 816 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 817 filename_size); 818 rc = virt_to_scatterlist(s->block_aligned_filename, 819 s->block_aligned_filename_size, s->src_sg, 2); 820 if (rc < 1) { 821 printk(KERN_ERR "%s: Internal error whilst attempting to " 822 "convert filename memory to scatterlist; rc = [%d]. " 823 "block_aligned_filename_size = [%zd]\n", __func__, rc, 824 s->block_aligned_filename_size); 825 goto out_release_free_unlock; 826 } 827 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 828 s->dst_sg, 2); 829 if (rc < 1) { 830 printk(KERN_ERR "%s: Internal error whilst attempting to " 831 "convert encrypted filename memory to scatterlist; " 832 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 833 __func__, rc, s->block_aligned_filename_size); 834 goto out_release_free_unlock; 835 } 836 /* The characters in the first block effectively do the job 837 * of the IV here, so we just use 0's for the IV. Note the 838 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 839 * >= ECRYPTFS_MAX_IV_BYTES. */ 840 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 841 s->desc.info = s->iv; 842 rc = crypto_blkcipher_setkey( 843 s->desc.tfm, 844 s->auth_tok->token.password.session_key_encryption_key, 845 mount_crypt_stat->global_default_fn_cipher_key_bytes); 846 if (rc < 0) { 847 printk(KERN_ERR "%s: Error setting key for crypto context; " 848 "rc = [%d]. s->auth_tok->token.password.session_key_" 849 "encryption_key = [0x%p]; mount_crypt_stat->" 850 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 851 rc, 852 s->auth_tok->token.password.session_key_encryption_key, 853 mount_crypt_stat->global_default_fn_cipher_key_bytes); 854 goto out_release_free_unlock; 855 } 856 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg, 857 s->block_aligned_filename_size); 858 if (rc) { 859 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 860 "rc = [%d]\n", __func__, rc); 861 goto out_release_free_unlock; 862 } 863 s->i += s->block_aligned_filename_size; 864 (*packet_size) = s->i; 865 (*remaining_bytes) -= (*packet_size); 866 out_release_free_unlock: 867 crypto_free_hash(s->hash_desc.tfm); 868 out_free_unlock: 869 kzfree(s->block_aligned_filename); 870 out_unlock: 871 mutex_unlock(s->tfm_mutex); 872 out: 873 if (auth_tok_key) { 874 up_write(&(auth_tok_key->sem)); 875 key_put(auth_tok_key); 876 } 877 kfree(s); 878 return rc; 879 } 880 881 struct ecryptfs_parse_tag_70_packet_silly_stack { 882 u8 cipher_code; 883 size_t max_packet_size; 884 size_t packet_size_len; 885 size_t parsed_tag_70_packet_size; 886 size_t block_aligned_filename_size; 887 size_t block_size; 888 size_t i; 889 struct mutex *tfm_mutex; 890 char *decrypted_filename; 891 struct ecryptfs_auth_tok *auth_tok; 892 struct scatterlist src_sg[2]; 893 struct scatterlist dst_sg[2]; 894 struct blkcipher_desc desc; 895 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 896 char iv[ECRYPTFS_MAX_IV_BYTES]; 897 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE]; 898 }; 899 900 /** 901 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 902 * @filename: This function kmalloc's the memory for the filename 903 * @filename_size: This function sets this to the amount of memory 904 * kmalloc'd for the filename 905 * @packet_size: This function sets this to the the number of octets 906 * in the packet parsed 907 * @mount_crypt_stat: The mount-wide cryptographic context 908 * @data: The memory location containing the start of the tag 70 909 * packet 910 * @max_packet_size: The maximum legal size of the packet to be parsed 911 * from @data 912 * 913 * Returns zero on success; non-zero otherwise 914 */ 915 int 916 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 917 size_t *packet_size, 918 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 919 char *data, size_t max_packet_size) 920 { 921 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 922 struct key *auth_tok_key = NULL; 923 int rc = 0; 924 925 (*packet_size) = 0; 926 (*filename_size) = 0; 927 (*filename) = NULL; 928 s = kmalloc(sizeof(*s), GFP_KERNEL); 929 if (!s) { 930 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 931 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 932 rc = -ENOMEM; 933 goto out; 934 } 935 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 936 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) { 937 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 938 "at least [%d]\n", __func__, max_packet_size, 939 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)); 940 rc = -EINVAL; 941 goto out; 942 } 943 /* Octet 0: Tag 70 identifier 944 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 945 * and block-aligned encrypted filename size) 946 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 947 * Octet N2-N3: Cipher identifier (1 octet) 948 * Octets N3-N4: Block-aligned encrypted filename 949 * - Consists of a minimum number of random numbers, a \0 950 * separator, and then the filename */ 951 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 952 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 953 "tag [0x%.2x]\n", __func__, 954 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 955 rc = -EINVAL; 956 goto out; 957 } 958 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 959 &s->parsed_tag_70_packet_size, 960 &s->packet_size_len); 961 if (rc) { 962 printk(KERN_WARNING "%s: Error parsing packet length; " 963 "rc = [%d]\n", __func__, rc); 964 goto out; 965 } 966 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 967 - ECRYPTFS_SIG_SIZE - 1); 968 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 969 > max_packet_size) { 970 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 971 "size is [%zd]\n", __func__, max_packet_size, 972 (1 + s->packet_size_len + 1 973 + s->block_aligned_filename_size)); 974 rc = -EINVAL; 975 goto out; 976 } 977 (*packet_size) += s->packet_size_len; 978 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 979 ECRYPTFS_SIG_SIZE); 980 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 981 (*packet_size) += ECRYPTFS_SIG_SIZE; 982 s->cipher_code = data[(*packet_size)++]; 983 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 984 if (rc) { 985 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 986 __func__, s->cipher_code); 987 goto out; 988 } 989 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 990 &s->auth_tok, mount_crypt_stat, 991 s->fnek_sig_hex); 992 if (rc) { 993 printk(KERN_ERR "%s: Error attempting to find auth tok for " 994 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 995 rc); 996 goto out; 997 } 998 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm, 999 &s->tfm_mutex, 1000 s->cipher_string); 1001 if (unlikely(rc)) { 1002 printk(KERN_ERR "Internal error whilst attempting to get " 1003 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1004 s->cipher_string, rc); 1005 goto out; 1006 } 1007 mutex_lock(s->tfm_mutex); 1008 rc = virt_to_scatterlist(&data[(*packet_size)], 1009 s->block_aligned_filename_size, s->src_sg, 2); 1010 if (rc < 1) { 1011 printk(KERN_ERR "%s: Internal error whilst attempting to " 1012 "convert encrypted filename memory to scatterlist; " 1013 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1014 __func__, rc, s->block_aligned_filename_size); 1015 goto out_unlock; 1016 } 1017 (*packet_size) += s->block_aligned_filename_size; 1018 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 1019 GFP_KERNEL); 1020 if (!s->decrypted_filename) { 1021 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1022 "kmalloc [%zd] bytes\n", __func__, 1023 s->block_aligned_filename_size); 1024 rc = -ENOMEM; 1025 goto out_unlock; 1026 } 1027 rc = virt_to_scatterlist(s->decrypted_filename, 1028 s->block_aligned_filename_size, s->dst_sg, 2); 1029 if (rc < 1) { 1030 printk(KERN_ERR "%s: Internal error whilst attempting to " 1031 "convert decrypted filename memory to scatterlist; " 1032 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1033 __func__, rc, s->block_aligned_filename_size); 1034 goto out_free_unlock; 1035 } 1036 /* The characters in the first block effectively do the job of 1037 * the IV here, so we just use 0's for the IV. Note the 1038 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1039 * >= ECRYPTFS_MAX_IV_BYTES. */ 1040 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 1041 s->desc.info = s->iv; 1042 /* TODO: Support other key modules than passphrase for 1043 * filename encryption */ 1044 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1045 rc = -EOPNOTSUPP; 1046 printk(KERN_INFO "%s: Filename encryption only supports " 1047 "password tokens\n", __func__); 1048 goto out_free_unlock; 1049 } 1050 rc = crypto_blkcipher_setkey( 1051 s->desc.tfm, 1052 s->auth_tok->token.password.session_key_encryption_key, 1053 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1054 if (rc < 0) { 1055 printk(KERN_ERR "%s: Error setting key for crypto context; " 1056 "rc = [%d]. s->auth_tok->token.password.session_key_" 1057 "encryption_key = [0x%p]; mount_crypt_stat->" 1058 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1059 rc, 1060 s->auth_tok->token.password.session_key_encryption_key, 1061 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1062 goto out_free_unlock; 1063 } 1064 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg, 1065 s->block_aligned_filename_size); 1066 if (rc) { 1067 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1068 "rc = [%d]\n", __func__, rc); 1069 goto out_free_unlock; 1070 } 1071 s->i = 0; 1072 while (s->decrypted_filename[s->i] != '\0' 1073 && s->i < s->block_aligned_filename_size) 1074 s->i++; 1075 if (s->i == s->block_aligned_filename_size) { 1076 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1077 "find valid separator between random characters and " 1078 "the filename\n", __func__); 1079 rc = -EINVAL; 1080 goto out_free_unlock; 1081 } 1082 s->i++; 1083 (*filename_size) = (s->block_aligned_filename_size - s->i); 1084 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1085 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1086 "invalid\n", __func__, (*filename_size)); 1087 rc = -EINVAL; 1088 goto out_free_unlock; 1089 } 1090 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1091 if (!(*filename)) { 1092 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1093 "kmalloc [%zd] bytes\n", __func__, 1094 ((*filename_size) + 1)); 1095 rc = -ENOMEM; 1096 goto out_free_unlock; 1097 } 1098 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1099 (*filename)[(*filename_size)] = '\0'; 1100 out_free_unlock: 1101 kfree(s->decrypted_filename); 1102 out_unlock: 1103 mutex_unlock(s->tfm_mutex); 1104 out: 1105 if (rc) { 1106 (*packet_size) = 0; 1107 (*filename_size) = 0; 1108 (*filename) = NULL; 1109 } 1110 if (auth_tok_key) { 1111 up_write(&(auth_tok_key->sem)); 1112 key_put(auth_tok_key); 1113 } 1114 kfree(s); 1115 return rc; 1116 } 1117 1118 static int 1119 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1120 { 1121 int rc = 0; 1122 1123 (*sig) = NULL; 1124 switch (auth_tok->token_type) { 1125 case ECRYPTFS_PASSWORD: 1126 (*sig) = auth_tok->token.password.signature; 1127 break; 1128 case ECRYPTFS_PRIVATE_KEY: 1129 (*sig) = auth_tok->token.private_key.signature; 1130 break; 1131 default: 1132 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1133 auth_tok->token_type); 1134 rc = -EINVAL; 1135 } 1136 return rc; 1137 } 1138 1139 /** 1140 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1141 * @auth_tok: The key authentication token used to decrypt the session key 1142 * @crypt_stat: The cryptographic context 1143 * 1144 * Returns zero on success; non-zero error otherwise. 1145 */ 1146 static int 1147 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1148 struct ecryptfs_crypt_stat *crypt_stat) 1149 { 1150 u8 cipher_code = 0; 1151 struct ecryptfs_msg_ctx *msg_ctx; 1152 struct ecryptfs_message *msg = NULL; 1153 char *auth_tok_sig; 1154 char *payload; 1155 size_t payload_len; 1156 int rc; 1157 1158 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1159 if (rc) { 1160 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1161 auth_tok->token_type); 1162 goto out; 1163 } 1164 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1165 &payload, &payload_len); 1166 if (rc) { 1167 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1168 goto out; 1169 } 1170 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1171 if (rc) { 1172 ecryptfs_printk(KERN_ERR, "Error sending message to " 1173 "ecryptfsd\n"); 1174 goto out; 1175 } 1176 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1177 if (rc) { 1178 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1179 "from the user space daemon\n"); 1180 rc = -EIO; 1181 goto out; 1182 } 1183 rc = parse_tag_65_packet(&(auth_tok->session_key), 1184 &cipher_code, msg); 1185 if (rc) { 1186 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1187 rc); 1188 goto out; 1189 } 1190 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1191 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1192 auth_tok->session_key.decrypted_key_size); 1193 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1194 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1195 if (rc) { 1196 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1197 cipher_code) 1198 goto out; 1199 } 1200 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1201 if (ecryptfs_verbosity > 0) { 1202 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1203 ecryptfs_dump_hex(crypt_stat->key, 1204 crypt_stat->key_size); 1205 } 1206 out: 1207 if (msg) 1208 kfree(msg); 1209 return rc; 1210 } 1211 1212 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1213 { 1214 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1215 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1216 1217 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1218 auth_tok_list_head, list) { 1219 list_del(&auth_tok_list_item->list); 1220 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1221 auth_tok_list_item); 1222 } 1223 } 1224 1225 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1226 1227 /** 1228 * parse_tag_1_packet 1229 * @crypt_stat: The cryptographic context to modify based on packet contents 1230 * @data: The raw bytes of the packet. 1231 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1232 * a new authentication token will be placed at the 1233 * end of this list for this packet. 1234 * @new_auth_tok: Pointer to a pointer to memory that this function 1235 * allocates; sets the memory address of the pointer to 1236 * NULL on error. This object is added to the 1237 * auth_tok_list. 1238 * @packet_size: This function writes the size of the parsed packet 1239 * into this memory location; zero on error. 1240 * @max_packet_size: The maximum allowable packet size 1241 * 1242 * Returns zero on success; non-zero on error. 1243 */ 1244 static int 1245 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1246 unsigned char *data, struct list_head *auth_tok_list, 1247 struct ecryptfs_auth_tok **new_auth_tok, 1248 size_t *packet_size, size_t max_packet_size) 1249 { 1250 size_t body_size; 1251 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1252 size_t length_size; 1253 int rc = 0; 1254 1255 (*packet_size) = 0; 1256 (*new_auth_tok) = NULL; 1257 /** 1258 * This format is inspired by OpenPGP; see RFC 2440 1259 * packet tag 1 1260 * 1261 * Tag 1 identifier (1 byte) 1262 * Max Tag 1 packet size (max 3 bytes) 1263 * Version (1 byte) 1264 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1265 * Cipher identifier (1 byte) 1266 * Encrypted key size (arbitrary) 1267 * 1268 * 12 bytes minimum packet size 1269 */ 1270 if (unlikely(max_packet_size < 12)) { 1271 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1272 rc = -EINVAL; 1273 goto out; 1274 } 1275 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1276 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1277 ECRYPTFS_TAG_1_PACKET_TYPE); 1278 rc = -EINVAL; 1279 goto out; 1280 } 1281 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1282 * at end of function upon failure */ 1283 auth_tok_list_item = 1284 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1285 GFP_KERNEL); 1286 if (!auth_tok_list_item) { 1287 printk(KERN_ERR "Unable to allocate memory\n"); 1288 rc = -ENOMEM; 1289 goto out; 1290 } 1291 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1292 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1293 &length_size); 1294 if (rc) { 1295 printk(KERN_WARNING "Error parsing packet length; " 1296 "rc = [%d]\n", rc); 1297 goto out_free; 1298 } 1299 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1300 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1301 rc = -EINVAL; 1302 goto out_free; 1303 } 1304 (*packet_size) += length_size; 1305 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1306 printk(KERN_WARNING "Packet size exceeds max\n"); 1307 rc = -EINVAL; 1308 goto out_free; 1309 } 1310 if (unlikely(data[(*packet_size)++] != 0x03)) { 1311 printk(KERN_WARNING "Unknown version number [%d]\n", 1312 data[(*packet_size) - 1]); 1313 rc = -EINVAL; 1314 goto out_free; 1315 } 1316 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1317 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1318 *packet_size += ECRYPTFS_SIG_SIZE; 1319 /* This byte is skipped because the kernel does not need to 1320 * know which public key encryption algorithm was used */ 1321 (*packet_size)++; 1322 (*new_auth_tok)->session_key.encrypted_key_size = 1323 body_size - (ECRYPTFS_SIG_SIZE + 2); 1324 if ((*new_auth_tok)->session_key.encrypted_key_size 1325 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1326 printk(KERN_WARNING "Tag 1 packet contains key larger " 1327 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); 1328 rc = -EINVAL; 1329 goto out; 1330 } 1331 memcpy((*new_auth_tok)->session_key.encrypted_key, 1332 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1333 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1334 (*new_auth_tok)->session_key.flags &= 1335 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1336 (*new_auth_tok)->session_key.flags |= 1337 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1338 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1339 (*new_auth_tok)->flags = 0; 1340 (*new_auth_tok)->session_key.flags &= 1341 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1342 (*new_auth_tok)->session_key.flags &= 1343 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1344 list_add(&auth_tok_list_item->list, auth_tok_list); 1345 goto out; 1346 out_free: 1347 (*new_auth_tok) = NULL; 1348 memset(auth_tok_list_item, 0, 1349 sizeof(struct ecryptfs_auth_tok_list_item)); 1350 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1351 auth_tok_list_item); 1352 out: 1353 if (rc) 1354 (*packet_size) = 0; 1355 return rc; 1356 } 1357 1358 /** 1359 * parse_tag_3_packet 1360 * @crypt_stat: The cryptographic context to modify based on packet 1361 * contents. 1362 * @data: The raw bytes of the packet. 1363 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1364 * a new authentication token will be placed at the end 1365 * of this list for this packet. 1366 * @new_auth_tok: Pointer to a pointer to memory that this function 1367 * allocates; sets the memory address of the pointer to 1368 * NULL on error. This object is added to the 1369 * auth_tok_list. 1370 * @packet_size: This function writes the size of the parsed packet 1371 * into this memory location; zero on error. 1372 * @max_packet_size: maximum number of bytes to parse 1373 * 1374 * Returns zero on success; non-zero on error. 1375 */ 1376 static int 1377 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1378 unsigned char *data, struct list_head *auth_tok_list, 1379 struct ecryptfs_auth_tok **new_auth_tok, 1380 size_t *packet_size, size_t max_packet_size) 1381 { 1382 size_t body_size; 1383 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1384 size_t length_size; 1385 int rc = 0; 1386 1387 (*packet_size) = 0; 1388 (*new_auth_tok) = NULL; 1389 /** 1390 *This format is inspired by OpenPGP; see RFC 2440 1391 * packet tag 3 1392 * 1393 * Tag 3 identifier (1 byte) 1394 * Max Tag 3 packet size (max 3 bytes) 1395 * Version (1 byte) 1396 * Cipher code (1 byte) 1397 * S2K specifier (1 byte) 1398 * Hash identifier (1 byte) 1399 * Salt (ECRYPTFS_SALT_SIZE) 1400 * Hash iterations (1 byte) 1401 * Encrypted key (arbitrary) 1402 * 1403 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1404 */ 1405 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1406 printk(KERN_ERR "Max packet size too large\n"); 1407 rc = -EINVAL; 1408 goto out; 1409 } 1410 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1411 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1412 ECRYPTFS_TAG_3_PACKET_TYPE); 1413 rc = -EINVAL; 1414 goto out; 1415 } 1416 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1417 * at end of function upon failure */ 1418 auth_tok_list_item = 1419 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1420 if (!auth_tok_list_item) { 1421 printk(KERN_ERR "Unable to allocate memory\n"); 1422 rc = -ENOMEM; 1423 goto out; 1424 } 1425 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1426 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1427 &length_size); 1428 if (rc) { 1429 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1430 rc); 1431 goto out_free; 1432 } 1433 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1434 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1435 rc = -EINVAL; 1436 goto out_free; 1437 } 1438 (*packet_size) += length_size; 1439 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1440 printk(KERN_ERR "Packet size exceeds max\n"); 1441 rc = -EINVAL; 1442 goto out_free; 1443 } 1444 (*new_auth_tok)->session_key.encrypted_key_size = 1445 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1446 if ((*new_auth_tok)->session_key.encrypted_key_size 1447 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1448 printk(KERN_WARNING "Tag 3 packet contains key larger " 1449 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1450 rc = -EINVAL; 1451 goto out_free; 1452 } 1453 if (unlikely(data[(*packet_size)++] != 0x04)) { 1454 printk(KERN_WARNING "Unknown version number [%d]\n", 1455 data[(*packet_size) - 1]); 1456 rc = -EINVAL; 1457 goto out_free; 1458 } 1459 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1460 (u16)data[(*packet_size)]); 1461 if (rc) 1462 goto out_free; 1463 /* A little extra work to differentiate among the AES key 1464 * sizes; see RFC2440 */ 1465 switch(data[(*packet_size)++]) { 1466 case RFC2440_CIPHER_AES_192: 1467 crypt_stat->key_size = 24; 1468 break; 1469 default: 1470 crypt_stat->key_size = 1471 (*new_auth_tok)->session_key.encrypted_key_size; 1472 } 1473 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1474 if (rc) 1475 goto out_free; 1476 if (unlikely(data[(*packet_size)++] != 0x03)) { 1477 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1478 rc = -ENOSYS; 1479 goto out_free; 1480 } 1481 /* TODO: finish the hash mapping */ 1482 switch (data[(*packet_size)++]) { 1483 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1484 /* Choose MD5 */ 1485 memcpy((*new_auth_tok)->token.password.salt, 1486 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1487 (*packet_size) += ECRYPTFS_SALT_SIZE; 1488 /* This conversion was taken straight from RFC2440 */ 1489 (*new_auth_tok)->token.password.hash_iterations = 1490 ((u32) 16 + (data[(*packet_size)] & 15)) 1491 << ((data[(*packet_size)] >> 4) + 6); 1492 (*packet_size)++; 1493 /* Friendly reminder: 1494 * (*new_auth_tok)->session_key.encrypted_key_size = 1495 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1496 memcpy((*new_auth_tok)->session_key.encrypted_key, 1497 &data[(*packet_size)], 1498 (*new_auth_tok)->session_key.encrypted_key_size); 1499 (*packet_size) += 1500 (*new_auth_tok)->session_key.encrypted_key_size; 1501 (*new_auth_tok)->session_key.flags &= 1502 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1503 (*new_auth_tok)->session_key.flags |= 1504 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1505 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1506 break; 1507 default: 1508 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1509 "[%d]\n", data[(*packet_size) - 1]); 1510 rc = -ENOSYS; 1511 goto out_free; 1512 } 1513 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1514 /* TODO: Parametarize; we might actually want userspace to 1515 * decrypt the session key. */ 1516 (*new_auth_tok)->session_key.flags &= 1517 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1518 (*new_auth_tok)->session_key.flags &= 1519 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1520 list_add(&auth_tok_list_item->list, auth_tok_list); 1521 goto out; 1522 out_free: 1523 (*new_auth_tok) = NULL; 1524 memset(auth_tok_list_item, 0, 1525 sizeof(struct ecryptfs_auth_tok_list_item)); 1526 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1527 auth_tok_list_item); 1528 out: 1529 if (rc) 1530 (*packet_size) = 0; 1531 return rc; 1532 } 1533 1534 /** 1535 * parse_tag_11_packet 1536 * @data: The raw bytes of the packet 1537 * @contents: This function writes the data contents of the literal 1538 * packet into this memory location 1539 * @max_contents_bytes: The maximum number of bytes that this function 1540 * is allowed to write into contents 1541 * @tag_11_contents_size: This function writes the size of the parsed 1542 * contents into this memory location; zero on 1543 * error 1544 * @packet_size: This function writes the size of the parsed packet 1545 * into this memory location; zero on error 1546 * @max_packet_size: maximum number of bytes to parse 1547 * 1548 * Returns zero on success; non-zero on error. 1549 */ 1550 static int 1551 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1552 size_t max_contents_bytes, size_t *tag_11_contents_size, 1553 size_t *packet_size, size_t max_packet_size) 1554 { 1555 size_t body_size; 1556 size_t length_size; 1557 int rc = 0; 1558 1559 (*packet_size) = 0; 1560 (*tag_11_contents_size) = 0; 1561 /* This format is inspired by OpenPGP; see RFC 2440 1562 * packet tag 11 1563 * 1564 * Tag 11 identifier (1 byte) 1565 * Max Tag 11 packet size (max 3 bytes) 1566 * Binary format specifier (1 byte) 1567 * Filename length (1 byte) 1568 * Filename ("_CONSOLE") (8 bytes) 1569 * Modification date (4 bytes) 1570 * Literal data (arbitrary) 1571 * 1572 * We need at least 16 bytes of data for the packet to even be 1573 * valid. 1574 */ 1575 if (max_packet_size < 16) { 1576 printk(KERN_ERR "Maximum packet size too small\n"); 1577 rc = -EINVAL; 1578 goto out; 1579 } 1580 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1581 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1582 rc = -EINVAL; 1583 goto out; 1584 } 1585 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1586 &length_size); 1587 if (rc) { 1588 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1589 goto out; 1590 } 1591 if (body_size < 14) { 1592 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1593 rc = -EINVAL; 1594 goto out; 1595 } 1596 (*packet_size) += length_size; 1597 (*tag_11_contents_size) = (body_size - 14); 1598 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1599 printk(KERN_ERR "Packet size exceeds max\n"); 1600 rc = -EINVAL; 1601 goto out; 1602 } 1603 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1604 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1605 "expected size\n"); 1606 rc = -EINVAL; 1607 goto out; 1608 } 1609 if (data[(*packet_size)++] != 0x62) { 1610 printk(KERN_WARNING "Unrecognizable packet\n"); 1611 rc = -EINVAL; 1612 goto out; 1613 } 1614 if (data[(*packet_size)++] != 0x08) { 1615 printk(KERN_WARNING "Unrecognizable packet\n"); 1616 rc = -EINVAL; 1617 goto out; 1618 } 1619 (*packet_size) += 12; /* Ignore filename and modification date */ 1620 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1621 (*packet_size) += (*tag_11_contents_size); 1622 out: 1623 if (rc) { 1624 (*packet_size) = 0; 1625 (*tag_11_contents_size) = 0; 1626 } 1627 return rc; 1628 } 1629 1630 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1631 struct ecryptfs_auth_tok **auth_tok, 1632 char *sig) 1633 { 1634 int rc = 0; 1635 1636 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1637 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1638 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1639 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1640 printk(KERN_ERR "Could not find key with description: [%s]\n", 1641 sig); 1642 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1643 (*auth_tok_key) = NULL; 1644 goto out; 1645 } 1646 } 1647 down_write(&(*auth_tok_key)->sem); 1648 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1649 if (rc) { 1650 up_write(&(*auth_tok_key)->sem); 1651 key_put(*auth_tok_key); 1652 (*auth_tok_key) = NULL; 1653 goto out; 1654 } 1655 out: 1656 return rc; 1657 } 1658 1659 /** 1660 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1661 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1662 * @crypt_stat: The cryptographic context 1663 * 1664 * Returns zero on success; non-zero error otherwise 1665 */ 1666 static int 1667 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1668 struct ecryptfs_crypt_stat *crypt_stat) 1669 { 1670 struct scatterlist dst_sg[2]; 1671 struct scatterlist src_sg[2]; 1672 struct mutex *tfm_mutex; 1673 struct blkcipher_desc desc = { 1674 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 1675 }; 1676 int rc = 0; 1677 1678 if (unlikely(ecryptfs_verbosity > 0)) { 1679 ecryptfs_printk( 1680 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1681 auth_tok->token.password.session_key_encryption_key_bytes); 1682 ecryptfs_dump_hex( 1683 auth_tok->token.password.session_key_encryption_key, 1684 auth_tok->token.password.session_key_encryption_key_bytes); 1685 } 1686 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 1687 crypt_stat->cipher); 1688 if (unlikely(rc)) { 1689 printk(KERN_ERR "Internal error whilst attempting to get " 1690 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1691 crypt_stat->cipher, rc); 1692 goto out; 1693 } 1694 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1695 auth_tok->session_key.encrypted_key_size, 1696 src_sg, 2); 1697 if (rc < 1 || rc > 2) { 1698 printk(KERN_ERR "Internal error whilst attempting to convert " 1699 "auth_tok->session_key.encrypted_key to scatterlist; " 1700 "expected rc = 1; got rc = [%d]. " 1701 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1702 auth_tok->session_key.encrypted_key_size); 1703 goto out; 1704 } 1705 auth_tok->session_key.decrypted_key_size = 1706 auth_tok->session_key.encrypted_key_size; 1707 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1708 auth_tok->session_key.decrypted_key_size, 1709 dst_sg, 2); 1710 if (rc < 1 || rc > 2) { 1711 printk(KERN_ERR "Internal error whilst attempting to convert " 1712 "auth_tok->session_key.decrypted_key to scatterlist; " 1713 "expected rc = 1; got rc = [%d]\n", rc); 1714 goto out; 1715 } 1716 mutex_lock(tfm_mutex); 1717 rc = crypto_blkcipher_setkey( 1718 desc.tfm, auth_tok->token.password.session_key_encryption_key, 1719 crypt_stat->key_size); 1720 if (unlikely(rc < 0)) { 1721 mutex_unlock(tfm_mutex); 1722 printk(KERN_ERR "Error setting key for crypto context\n"); 1723 rc = -EINVAL; 1724 goto out; 1725 } 1726 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg, 1727 auth_tok->session_key.encrypted_key_size); 1728 mutex_unlock(tfm_mutex); 1729 if (unlikely(rc)) { 1730 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1731 goto out; 1732 } 1733 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1734 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1735 auth_tok->session_key.decrypted_key_size); 1736 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1737 if (unlikely(ecryptfs_verbosity > 0)) { 1738 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1739 crypt_stat->key_size); 1740 ecryptfs_dump_hex(crypt_stat->key, 1741 crypt_stat->key_size); 1742 } 1743 out: 1744 return rc; 1745 } 1746 1747 /** 1748 * ecryptfs_parse_packet_set 1749 * @crypt_stat: The cryptographic context 1750 * @src: Virtual address of region of memory containing the packets 1751 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1752 * 1753 * Get crypt_stat to have the file's session key if the requisite key 1754 * is available to decrypt the session key. 1755 * 1756 * Returns Zero if a valid authentication token was retrieved and 1757 * processed; negative value for file not encrypted or for error 1758 * conditions. 1759 */ 1760 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1761 unsigned char *src, 1762 struct dentry *ecryptfs_dentry) 1763 { 1764 size_t i = 0; 1765 size_t found_auth_tok; 1766 size_t next_packet_is_auth_tok_packet; 1767 struct list_head auth_tok_list; 1768 struct ecryptfs_auth_tok *matching_auth_tok; 1769 struct ecryptfs_auth_tok *candidate_auth_tok; 1770 char *candidate_auth_tok_sig; 1771 size_t packet_size; 1772 struct ecryptfs_auth_tok *new_auth_tok; 1773 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1774 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1775 size_t tag_11_contents_size; 1776 size_t tag_11_packet_size; 1777 struct key *auth_tok_key = NULL; 1778 int rc = 0; 1779 1780 INIT_LIST_HEAD(&auth_tok_list); 1781 /* Parse the header to find as many packets as we can; these will be 1782 * added the our &auth_tok_list */ 1783 next_packet_is_auth_tok_packet = 1; 1784 while (next_packet_is_auth_tok_packet) { 1785 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i); 1786 1787 switch (src[i]) { 1788 case ECRYPTFS_TAG_3_PACKET_TYPE: 1789 rc = parse_tag_3_packet(crypt_stat, 1790 (unsigned char *)&src[i], 1791 &auth_tok_list, &new_auth_tok, 1792 &packet_size, max_packet_size); 1793 if (rc) { 1794 ecryptfs_printk(KERN_ERR, "Error parsing " 1795 "tag 3 packet\n"); 1796 rc = -EIO; 1797 goto out_wipe_list; 1798 } 1799 i += packet_size; 1800 rc = parse_tag_11_packet((unsigned char *)&src[i], 1801 sig_tmp_space, 1802 ECRYPTFS_SIG_SIZE, 1803 &tag_11_contents_size, 1804 &tag_11_packet_size, 1805 max_packet_size); 1806 if (rc) { 1807 ecryptfs_printk(KERN_ERR, "No valid " 1808 "(ecryptfs-specific) literal " 1809 "packet containing " 1810 "authentication token " 1811 "signature found after " 1812 "tag 3 packet\n"); 1813 rc = -EIO; 1814 goto out_wipe_list; 1815 } 1816 i += tag_11_packet_size; 1817 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1818 ecryptfs_printk(KERN_ERR, "Expected " 1819 "signature of size [%d]; " 1820 "read size [%zd]\n", 1821 ECRYPTFS_SIG_SIZE, 1822 tag_11_contents_size); 1823 rc = -EIO; 1824 goto out_wipe_list; 1825 } 1826 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1827 sig_tmp_space, tag_11_contents_size); 1828 new_auth_tok->token.password.signature[ 1829 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1830 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1831 break; 1832 case ECRYPTFS_TAG_1_PACKET_TYPE: 1833 rc = parse_tag_1_packet(crypt_stat, 1834 (unsigned char *)&src[i], 1835 &auth_tok_list, &new_auth_tok, 1836 &packet_size, max_packet_size); 1837 if (rc) { 1838 ecryptfs_printk(KERN_ERR, "Error parsing " 1839 "tag 1 packet\n"); 1840 rc = -EIO; 1841 goto out_wipe_list; 1842 } 1843 i += packet_size; 1844 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1845 break; 1846 case ECRYPTFS_TAG_11_PACKET_TYPE: 1847 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1848 "(Tag 11 not allowed by itself)\n"); 1849 rc = -EIO; 1850 goto out_wipe_list; 1851 break; 1852 default: 1853 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1854 "of the file header; hex value of " 1855 "character is [0x%.2x]\n", i, src[i]); 1856 next_packet_is_auth_tok_packet = 0; 1857 } 1858 } 1859 if (list_empty(&auth_tok_list)) { 1860 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1861 "eCryptfs file; this is not supported in this version " 1862 "of the eCryptfs kernel module\n"); 1863 rc = -EINVAL; 1864 goto out; 1865 } 1866 /* auth_tok_list contains the set of authentication tokens 1867 * parsed from the metadata. We need to find a matching 1868 * authentication token that has the secret component(s) 1869 * necessary to decrypt the EFEK in the auth_tok parsed from 1870 * the metadata. There may be several potential matches, but 1871 * just one will be sufficient to decrypt to get the FEK. */ 1872 find_next_matching_auth_tok: 1873 found_auth_tok = 0; 1874 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1875 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1876 if (unlikely(ecryptfs_verbosity > 0)) { 1877 ecryptfs_printk(KERN_DEBUG, 1878 "Considering cadidate auth tok:\n"); 1879 ecryptfs_dump_auth_tok(candidate_auth_tok); 1880 } 1881 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1882 candidate_auth_tok); 1883 if (rc) { 1884 printk(KERN_ERR 1885 "Unrecognized candidate auth tok type: [%d]\n", 1886 candidate_auth_tok->token_type); 1887 rc = -EINVAL; 1888 goto out_wipe_list; 1889 } 1890 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1891 &matching_auth_tok, 1892 crypt_stat->mount_crypt_stat, 1893 candidate_auth_tok_sig); 1894 if (!rc) { 1895 found_auth_tok = 1; 1896 goto found_matching_auth_tok; 1897 } 1898 } 1899 if (!found_auth_tok) { 1900 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1901 "authentication token\n"); 1902 rc = -EIO; 1903 goto out_wipe_list; 1904 } 1905 found_matching_auth_tok: 1906 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1907 memcpy(&(candidate_auth_tok->token.private_key), 1908 &(matching_auth_tok->token.private_key), 1909 sizeof(struct ecryptfs_private_key)); 1910 up_write(&(auth_tok_key->sem)); 1911 key_put(auth_tok_key); 1912 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1913 crypt_stat); 1914 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1915 memcpy(&(candidate_auth_tok->token.password), 1916 &(matching_auth_tok->token.password), 1917 sizeof(struct ecryptfs_password)); 1918 up_write(&(auth_tok_key->sem)); 1919 key_put(auth_tok_key); 1920 rc = decrypt_passphrase_encrypted_session_key( 1921 candidate_auth_tok, crypt_stat); 1922 } else { 1923 up_write(&(auth_tok_key->sem)); 1924 key_put(auth_tok_key); 1925 rc = -EINVAL; 1926 } 1927 if (rc) { 1928 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1929 1930 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1931 "session key for authentication token with sig " 1932 "[%.*s]; rc = [%d]. Removing auth tok " 1933 "candidate from the list and searching for " 1934 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1935 candidate_auth_tok_sig, rc); 1936 list_for_each_entry_safe(auth_tok_list_item, 1937 auth_tok_list_item_tmp, 1938 &auth_tok_list, list) { 1939 if (candidate_auth_tok 1940 == &auth_tok_list_item->auth_tok) { 1941 list_del(&auth_tok_list_item->list); 1942 kmem_cache_free( 1943 ecryptfs_auth_tok_list_item_cache, 1944 auth_tok_list_item); 1945 goto find_next_matching_auth_tok; 1946 } 1947 } 1948 BUG(); 1949 } 1950 rc = ecryptfs_compute_root_iv(crypt_stat); 1951 if (rc) { 1952 ecryptfs_printk(KERN_ERR, "Error computing " 1953 "the root IV\n"); 1954 goto out_wipe_list; 1955 } 1956 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1957 if (rc) { 1958 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1959 "context for cipher [%s]; rc = [%d]\n", 1960 crypt_stat->cipher, rc); 1961 } 1962 out_wipe_list: 1963 wipe_auth_tok_list(&auth_tok_list); 1964 out: 1965 return rc; 1966 } 1967 1968 static int 1969 pki_encrypt_session_key(struct key *auth_tok_key, 1970 struct ecryptfs_auth_tok *auth_tok, 1971 struct ecryptfs_crypt_stat *crypt_stat, 1972 struct ecryptfs_key_record *key_rec) 1973 { 1974 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1975 char *payload = NULL; 1976 size_t payload_len; 1977 struct ecryptfs_message *msg; 1978 int rc; 1979 1980 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1981 ecryptfs_code_for_cipher_string( 1982 crypt_stat->cipher, 1983 crypt_stat->key_size), 1984 crypt_stat, &payload, &payload_len); 1985 up_write(&(auth_tok_key->sem)); 1986 key_put(auth_tok_key); 1987 if (rc) { 1988 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1989 goto out; 1990 } 1991 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1992 if (rc) { 1993 ecryptfs_printk(KERN_ERR, "Error sending message to " 1994 "ecryptfsd\n"); 1995 goto out; 1996 } 1997 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1998 if (rc) { 1999 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 2000 "from the user space daemon\n"); 2001 rc = -EIO; 2002 goto out; 2003 } 2004 rc = parse_tag_67_packet(key_rec, msg); 2005 if (rc) 2006 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2007 kfree(msg); 2008 out: 2009 kfree(payload); 2010 return rc; 2011 } 2012 /** 2013 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2014 * @dest: Buffer into which to write the packet 2015 * @remaining_bytes: Maximum number of bytes that can be writtn 2016 * @auth_tok_key: The authentication token key to unlock and put when done with 2017 * @auth_tok 2018 * @auth_tok: The authentication token used for generating the tag 1 packet 2019 * @crypt_stat: The cryptographic context 2020 * @key_rec: The key record struct for the tag 1 packet 2021 * @packet_size: This function will write the number of bytes that end 2022 * up constituting the packet; set to zero on error 2023 * 2024 * Returns zero on success; non-zero on error. 2025 */ 2026 static int 2027 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2028 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2029 struct ecryptfs_crypt_stat *crypt_stat, 2030 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2031 { 2032 size_t i; 2033 size_t encrypted_session_key_valid = 0; 2034 size_t packet_size_length; 2035 size_t max_packet_size; 2036 int rc = 0; 2037 2038 (*packet_size) = 0; 2039 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2040 ECRYPTFS_SIG_SIZE); 2041 encrypted_session_key_valid = 0; 2042 for (i = 0; i < crypt_stat->key_size; i++) 2043 encrypted_session_key_valid |= 2044 auth_tok->session_key.encrypted_key[i]; 2045 if (encrypted_session_key_valid) { 2046 memcpy(key_rec->enc_key, 2047 auth_tok->session_key.encrypted_key, 2048 auth_tok->session_key.encrypted_key_size); 2049 up_write(&(auth_tok_key->sem)); 2050 key_put(auth_tok_key); 2051 goto encrypted_session_key_set; 2052 } 2053 if (auth_tok->session_key.encrypted_key_size == 0) 2054 auth_tok->session_key.encrypted_key_size = 2055 auth_tok->token.private_key.key_size; 2056 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2057 key_rec); 2058 if (rc) { 2059 printk(KERN_ERR "Failed to encrypt session key via a key " 2060 "module; rc = [%d]\n", rc); 2061 goto out; 2062 } 2063 if (ecryptfs_verbosity > 0) { 2064 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2065 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2066 } 2067 encrypted_session_key_set: 2068 /* This format is inspired by OpenPGP; see RFC 2440 2069 * packet tag 1 */ 2070 max_packet_size = (1 /* Tag 1 identifier */ 2071 + 3 /* Max Tag 1 packet size */ 2072 + 1 /* Version */ 2073 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2074 + 1 /* Cipher identifier */ 2075 + key_rec->enc_key_size); /* Encrypted key size */ 2076 if (max_packet_size > (*remaining_bytes)) { 2077 printk(KERN_ERR "Packet length larger than maximum allowable; " 2078 "need up to [%td] bytes, but there are only [%td] " 2079 "available\n", max_packet_size, (*remaining_bytes)); 2080 rc = -EINVAL; 2081 goto out; 2082 } 2083 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2084 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2085 (max_packet_size - 4), 2086 &packet_size_length); 2087 if (rc) { 2088 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2089 "header; cannot generate packet length\n"); 2090 goto out; 2091 } 2092 (*packet_size) += packet_size_length; 2093 dest[(*packet_size)++] = 0x03; /* version 3 */ 2094 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2095 (*packet_size) += ECRYPTFS_SIG_SIZE; 2096 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2097 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2098 key_rec->enc_key_size); 2099 (*packet_size) += key_rec->enc_key_size; 2100 out: 2101 if (rc) 2102 (*packet_size) = 0; 2103 else 2104 (*remaining_bytes) -= (*packet_size); 2105 return rc; 2106 } 2107 2108 /** 2109 * write_tag_11_packet 2110 * @dest: Target into which Tag 11 packet is to be written 2111 * @remaining_bytes: Maximum packet length 2112 * @contents: Byte array of contents to copy in 2113 * @contents_length: Number of bytes in contents 2114 * @packet_length: Length of the Tag 11 packet written; zero on error 2115 * 2116 * Returns zero on success; non-zero on error. 2117 */ 2118 static int 2119 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2120 size_t contents_length, size_t *packet_length) 2121 { 2122 size_t packet_size_length; 2123 size_t max_packet_size; 2124 int rc = 0; 2125 2126 (*packet_length) = 0; 2127 /* This format is inspired by OpenPGP; see RFC 2440 2128 * packet tag 11 */ 2129 max_packet_size = (1 /* Tag 11 identifier */ 2130 + 3 /* Max Tag 11 packet size */ 2131 + 1 /* Binary format specifier */ 2132 + 1 /* Filename length */ 2133 + 8 /* Filename ("_CONSOLE") */ 2134 + 4 /* Modification date */ 2135 + contents_length); /* Literal data */ 2136 if (max_packet_size > (*remaining_bytes)) { 2137 printk(KERN_ERR "Packet length larger than maximum allowable; " 2138 "need up to [%td] bytes, but there are only [%td] " 2139 "available\n", max_packet_size, (*remaining_bytes)); 2140 rc = -EINVAL; 2141 goto out; 2142 } 2143 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2144 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2145 (max_packet_size - 4), 2146 &packet_size_length); 2147 if (rc) { 2148 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2149 "generate packet length. rc = [%d]\n", rc); 2150 goto out; 2151 } 2152 (*packet_length) += packet_size_length; 2153 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2154 dest[(*packet_length)++] = 8; 2155 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2156 (*packet_length) += 8; 2157 memset(&dest[(*packet_length)], 0x00, 4); 2158 (*packet_length) += 4; 2159 memcpy(&dest[(*packet_length)], contents, contents_length); 2160 (*packet_length) += contents_length; 2161 out: 2162 if (rc) 2163 (*packet_length) = 0; 2164 else 2165 (*remaining_bytes) -= (*packet_length); 2166 return rc; 2167 } 2168 2169 /** 2170 * write_tag_3_packet 2171 * @dest: Buffer into which to write the packet 2172 * @remaining_bytes: Maximum number of bytes that can be written 2173 * @auth_tok: Authentication token 2174 * @crypt_stat: The cryptographic context 2175 * @key_rec: encrypted key 2176 * @packet_size: This function will write the number of bytes that end 2177 * up constituting the packet; set to zero on error 2178 * 2179 * Returns zero on success; non-zero on error. 2180 */ 2181 static int 2182 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2183 struct ecryptfs_auth_tok *auth_tok, 2184 struct ecryptfs_crypt_stat *crypt_stat, 2185 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2186 { 2187 size_t i; 2188 size_t encrypted_session_key_valid = 0; 2189 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2190 struct scatterlist dst_sg[2]; 2191 struct scatterlist src_sg[2]; 2192 struct mutex *tfm_mutex = NULL; 2193 u8 cipher_code; 2194 size_t packet_size_length; 2195 size_t max_packet_size; 2196 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2197 crypt_stat->mount_crypt_stat; 2198 struct blkcipher_desc desc = { 2199 .tfm = NULL, 2200 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 2201 }; 2202 int rc = 0; 2203 2204 (*packet_size) = 0; 2205 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2206 ECRYPTFS_SIG_SIZE); 2207 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 2208 crypt_stat->cipher); 2209 if (unlikely(rc)) { 2210 printk(KERN_ERR "Internal error whilst attempting to get " 2211 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2212 crypt_stat->cipher, rc); 2213 goto out; 2214 } 2215 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2216 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm); 2217 2218 printk(KERN_WARNING "No key size specified at mount; " 2219 "defaulting to [%d]\n", alg->max_keysize); 2220 mount_crypt_stat->global_default_cipher_key_size = 2221 alg->max_keysize; 2222 } 2223 if (crypt_stat->key_size == 0) 2224 crypt_stat->key_size = 2225 mount_crypt_stat->global_default_cipher_key_size; 2226 if (auth_tok->session_key.encrypted_key_size == 0) 2227 auth_tok->session_key.encrypted_key_size = 2228 crypt_stat->key_size; 2229 if (crypt_stat->key_size == 24 2230 && strcmp("aes", crypt_stat->cipher) == 0) { 2231 memset((crypt_stat->key + 24), 0, 8); 2232 auth_tok->session_key.encrypted_key_size = 32; 2233 } else 2234 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2235 key_rec->enc_key_size = 2236 auth_tok->session_key.encrypted_key_size; 2237 encrypted_session_key_valid = 0; 2238 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2239 encrypted_session_key_valid |= 2240 auth_tok->session_key.encrypted_key[i]; 2241 if (encrypted_session_key_valid) { 2242 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2243 "using auth_tok->session_key.encrypted_key, " 2244 "where key_rec->enc_key_size = [%zd]\n", 2245 key_rec->enc_key_size); 2246 memcpy(key_rec->enc_key, 2247 auth_tok->session_key.encrypted_key, 2248 key_rec->enc_key_size); 2249 goto encrypted_session_key_set; 2250 } 2251 if (auth_tok->token.password.flags & 2252 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2253 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2254 "session key encryption key of size [%d]\n", 2255 auth_tok->token.password. 2256 session_key_encryption_key_bytes); 2257 memcpy(session_key_encryption_key, 2258 auth_tok->token.password.session_key_encryption_key, 2259 crypt_stat->key_size); 2260 ecryptfs_printk(KERN_DEBUG, 2261 "Cached session key encryption key:\n"); 2262 if (ecryptfs_verbosity > 0) 2263 ecryptfs_dump_hex(session_key_encryption_key, 16); 2264 } 2265 if (unlikely(ecryptfs_verbosity > 0)) { 2266 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2267 ecryptfs_dump_hex(session_key_encryption_key, 16); 2268 } 2269 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2270 src_sg, 2); 2271 if (rc < 1 || rc > 2) { 2272 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2273 "for crypt_stat session key; expected rc = 1; " 2274 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2275 rc, key_rec->enc_key_size); 2276 rc = -ENOMEM; 2277 goto out; 2278 } 2279 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2280 dst_sg, 2); 2281 if (rc < 1 || rc > 2) { 2282 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2283 "for crypt_stat encrypted session key; " 2284 "expected rc = 1; got rc = [%d]. " 2285 "key_rec->enc_key_size = [%zd]\n", rc, 2286 key_rec->enc_key_size); 2287 rc = -ENOMEM; 2288 goto out; 2289 } 2290 mutex_lock(tfm_mutex); 2291 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key, 2292 crypt_stat->key_size); 2293 if (rc < 0) { 2294 mutex_unlock(tfm_mutex); 2295 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2296 "context; rc = [%d]\n", rc); 2297 goto out; 2298 } 2299 rc = 0; 2300 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2301 crypt_stat->key_size); 2302 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg, 2303 (*key_rec).enc_key_size); 2304 mutex_unlock(tfm_mutex); 2305 if (rc) { 2306 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2307 goto out; 2308 } 2309 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2310 if (ecryptfs_verbosity > 0) { 2311 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2312 key_rec->enc_key_size); 2313 ecryptfs_dump_hex(key_rec->enc_key, 2314 key_rec->enc_key_size); 2315 } 2316 encrypted_session_key_set: 2317 /* This format is inspired by OpenPGP; see RFC 2440 2318 * packet tag 3 */ 2319 max_packet_size = (1 /* Tag 3 identifier */ 2320 + 3 /* Max Tag 3 packet size */ 2321 + 1 /* Version */ 2322 + 1 /* Cipher code */ 2323 + 1 /* S2K specifier */ 2324 + 1 /* Hash identifier */ 2325 + ECRYPTFS_SALT_SIZE /* Salt */ 2326 + 1 /* Hash iterations */ 2327 + key_rec->enc_key_size); /* Encrypted key size */ 2328 if (max_packet_size > (*remaining_bytes)) { 2329 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2330 "there are only [%td] available\n", max_packet_size, 2331 (*remaining_bytes)); 2332 rc = -EINVAL; 2333 goto out; 2334 } 2335 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2336 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2337 * to get the number of octets in the actual Tag 3 packet */ 2338 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2339 (max_packet_size - 4), 2340 &packet_size_length); 2341 if (rc) { 2342 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2343 "generate packet length. rc = [%d]\n", rc); 2344 goto out; 2345 } 2346 (*packet_size) += packet_size_length; 2347 dest[(*packet_size)++] = 0x04; /* version 4 */ 2348 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2349 * specified with strings */ 2350 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2351 crypt_stat->key_size); 2352 if (cipher_code == 0) { 2353 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2354 "cipher [%s]\n", crypt_stat->cipher); 2355 rc = -EINVAL; 2356 goto out; 2357 } 2358 dest[(*packet_size)++] = cipher_code; 2359 dest[(*packet_size)++] = 0x03; /* S2K */ 2360 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2361 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2362 ECRYPTFS_SALT_SIZE); 2363 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2364 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2365 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2366 key_rec->enc_key_size); 2367 (*packet_size) += key_rec->enc_key_size; 2368 out: 2369 if (rc) 2370 (*packet_size) = 0; 2371 else 2372 (*remaining_bytes) -= (*packet_size); 2373 return rc; 2374 } 2375 2376 struct kmem_cache *ecryptfs_key_record_cache; 2377 2378 /** 2379 * ecryptfs_generate_key_packet_set 2380 * @dest_base: Virtual address from which to write the key record set 2381 * @crypt_stat: The cryptographic context from which the 2382 * authentication tokens will be retrieved 2383 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2384 * for the global parameters 2385 * @len: The amount written 2386 * @max: The maximum amount of data allowed to be written 2387 * 2388 * Generates a key packet set and writes it to the virtual address 2389 * passed in. 2390 * 2391 * Returns zero on success; non-zero on error. 2392 */ 2393 int 2394 ecryptfs_generate_key_packet_set(char *dest_base, 2395 struct ecryptfs_crypt_stat *crypt_stat, 2396 struct dentry *ecryptfs_dentry, size_t *len, 2397 size_t max) 2398 { 2399 struct ecryptfs_auth_tok *auth_tok; 2400 struct key *auth_tok_key = NULL; 2401 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2402 &ecryptfs_superblock_to_private( 2403 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2404 size_t written; 2405 struct ecryptfs_key_record *key_rec; 2406 struct ecryptfs_key_sig *key_sig; 2407 int rc = 0; 2408 2409 (*len) = 0; 2410 mutex_lock(&crypt_stat->keysig_list_mutex); 2411 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2412 if (!key_rec) { 2413 rc = -ENOMEM; 2414 goto out; 2415 } 2416 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2417 crypt_stat_list) { 2418 memset(key_rec, 0, sizeof(*key_rec)); 2419 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2420 &auth_tok, 2421 mount_crypt_stat, 2422 key_sig->keysig); 2423 if (rc) { 2424 printk(KERN_WARNING "Unable to retrieve auth tok with " 2425 "sig = [%s]\n", key_sig->keysig); 2426 rc = process_find_global_auth_tok_for_sig_err(rc); 2427 goto out_free; 2428 } 2429 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2430 rc = write_tag_3_packet((dest_base + (*len)), 2431 &max, auth_tok, 2432 crypt_stat, key_rec, 2433 &written); 2434 up_write(&(auth_tok_key->sem)); 2435 key_put(auth_tok_key); 2436 if (rc) { 2437 ecryptfs_printk(KERN_WARNING, "Error " 2438 "writing tag 3 packet\n"); 2439 goto out_free; 2440 } 2441 (*len) += written; 2442 /* Write auth tok signature packet */ 2443 rc = write_tag_11_packet((dest_base + (*len)), &max, 2444 key_rec->sig, 2445 ECRYPTFS_SIG_SIZE, &written); 2446 if (rc) { 2447 ecryptfs_printk(KERN_ERR, "Error writing " 2448 "auth tok signature packet\n"); 2449 goto out_free; 2450 } 2451 (*len) += written; 2452 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2453 rc = write_tag_1_packet(dest_base + (*len), &max, 2454 auth_tok_key, auth_tok, 2455 crypt_stat, key_rec, &written); 2456 if (rc) { 2457 ecryptfs_printk(KERN_WARNING, "Error " 2458 "writing tag 1 packet\n"); 2459 goto out_free; 2460 } 2461 (*len) += written; 2462 } else { 2463 up_write(&(auth_tok_key->sem)); 2464 key_put(auth_tok_key); 2465 ecryptfs_printk(KERN_WARNING, "Unsupported " 2466 "authentication token type\n"); 2467 rc = -EINVAL; 2468 goto out_free; 2469 } 2470 } 2471 if (likely(max > 0)) { 2472 dest_base[(*len)] = 0x00; 2473 } else { 2474 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2475 rc = -EIO; 2476 } 2477 out_free: 2478 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2479 out: 2480 if (rc) 2481 (*len) = 0; 2482 mutex_unlock(&crypt_stat->keysig_list_mutex); 2483 return rc; 2484 } 2485 2486 struct kmem_cache *ecryptfs_key_sig_cache; 2487 2488 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2489 { 2490 struct ecryptfs_key_sig *new_key_sig; 2491 2492 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2493 if (!new_key_sig) { 2494 printk(KERN_ERR 2495 "Error allocating from ecryptfs_key_sig_cache\n"); 2496 return -ENOMEM; 2497 } 2498 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2499 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2500 /* Caller must hold keysig_list_mutex */ 2501 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2502 2503 return 0; 2504 } 2505 2506 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2507 2508 int 2509 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2510 char *sig, u32 global_auth_tok_flags) 2511 { 2512 struct ecryptfs_global_auth_tok *new_auth_tok; 2513 int rc = 0; 2514 2515 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2516 GFP_KERNEL); 2517 if (!new_auth_tok) { 2518 rc = -ENOMEM; 2519 printk(KERN_ERR "Error allocating from " 2520 "ecryptfs_global_auth_tok_cache\n"); 2521 goto out; 2522 } 2523 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2524 new_auth_tok->flags = global_auth_tok_flags; 2525 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2526 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2527 list_add(&new_auth_tok->mount_crypt_stat_list, 2528 &mount_crypt_stat->global_auth_tok_list); 2529 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2530 out: 2531 return rc; 2532 } 2533 2534