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/pagemap.h> 30 #include <linux/key.h> 31 #include <linux/random.h> 32 #include <linux/crypto.h> 33 #include <linux/scatterlist.h> 34 #include <linux/slab.h> 35 #include "ecryptfs_kernel.h" 36 37 /** 38 * request_key returned an error instead of a valid key address; 39 * determine the type of error, make appropriate log entries, and 40 * return an error code. 41 */ 42 static int process_request_key_err(long err_code) 43 { 44 int rc = 0; 45 46 switch (err_code) { 47 case -ENOKEY: 48 ecryptfs_printk(KERN_WARNING, "No key\n"); 49 rc = -ENOENT; 50 break; 51 case -EKEYEXPIRED: 52 ecryptfs_printk(KERN_WARNING, "Key expired\n"); 53 rc = -ETIME; 54 break; 55 case -EKEYREVOKED: 56 ecryptfs_printk(KERN_WARNING, "Key revoked\n"); 57 rc = -EINVAL; 58 break; 59 default: 60 ecryptfs_printk(KERN_WARNING, "Unknown error code: " 61 "[0x%.16lx]\n", err_code); 62 rc = -EINVAL; 63 } 64 return rc; 65 } 66 67 static int process_find_global_auth_tok_for_sig_err(int err_code) 68 { 69 int rc = err_code; 70 71 switch (err_code) { 72 case -ENOENT: 73 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n"); 74 break; 75 case -EINVAL: 76 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n"); 77 break; 78 default: 79 rc = process_request_key_err(err_code); 80 break; 81 } 82 return rc; 83 } 84 85 /** 86 * ecryptfs_parse_packet_length 87 * @data: Pointer to memory containing length at offset 88 * @size: This function writes the decoded size to this memory 89 * address; zero on error 90 * @length_size: The number of bytes occupied by the encoded length 91 * 92 * Returns zero on success; non-zero on error 93 */ 94 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, 95 size_t *length_size) 96 { 97 int rc = 0; 98 99 (*length_size) = 0; 100 (*size) = 0; 101 if (data[0] < 192) { 102 /* One-byte length */ 103 (*size) = data[0]; 104 (*length_size) = 1; 105 } else if (data[0] < 224) { 106 /* Two-byte length */ 107 (*size) = (data[0] - 192) * 256; 108 (*size) += data[1] + 192; 109 (*length_size) = 2; 110 } else if (data[0] == 255) { 111 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 112 ecryptfs_printk(KERN_ERR, "Five-byte packet length not " 113 "supported\n"); 114 rc = -EINVAL; 115 goto out; 116 } else { 117 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n"); 118 rc = -EINVAL; 119 goto out; 120 } 121 out: 122 return rc; 123 } 124 125 /** 126 * ecryptfs_write_packet_length 127 * @dest: The byte array target into which to write the length. Must 128 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated. 129 * @size: The length to write. 130 * @packet_size_length: The number of bytes used to encode the packet 131 * length is written to this address. 132 * 133 * Returns zero on success; non-zero on error. 134 */ 135 int ecryptfs_write_packet_length(char *dest, size_t size, 136 size_t *packet_size_length) 137 { 138 int rc = 0; 139 140 if (size < 192) { 141 dest[0] = size; 142 (*packet_size_length) = 1; 143 } else if (size < 65536) { 144 dest[0] = (((size - 192) / 256) + 192); 145 dest[1] = ((size - 192) % 256); 146 (*packet_size_length) = 2; 147 } else { 148 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 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 = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 682 + s->block_aligned_filename_size); 683 if (dest == NULL) { 684 (*packet_size) = s->max_packet_size; 685 goto out_unlock; 686 } 687 if (s->max_packet_size > (*remaining_bytes)) { 688 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 689 "[%zd] available\n", __func__, s->max_packet_size, 690 (*remaining_bytes)); 691 rc = -EINVAL; 692 goto out_unlock; 693 } 694 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 695 GFP_KERNEL); 696 if (!s->block_aligned_filename) { 697 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 698 "kzalloc [%zd] bytes\n", __func__, 699 s->block_aligned_filename_size); 700 rc = -ENOMEM; 701 goto out_unlock; 702 } 703 s->i = 0; 704 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 705 rc = ecryptfs_write_packet_length(&dest[s->i], 706 (ECRYPTFS_SIG_SIZE 707 + 1 /* Cipher code */ 708 + s->block_aligned_filename_size), 709 &s->packet_size_len); 710 if (rc) { 711 printk(KERN_ERR "%s: Error generating tag 70 packet " 712 "header; cannot generate packet length; rc = [%d]\n", 713 __func__, rc); 714 goto out_free_unlock; 715 } 716 s->i += s->packet_size_len; 717 ecryptfs_from_hex(&dest[s->i], 718 mount_crypt_stat->global_default_fnek_sig, 719 ECRYPTFS_SIG_SIZE); 720 s->i += ECRYPTFS_SIG_SIZE; 721 s->cipher_code = ecryptfs_code_for_cipher_string( 722 mount_crypt_stat->global_default_fn_cipher_name, 723 mount_crypt_stat->global_default_fn_cipher_key_bytes); 724 if (s->cipher_code == 0) { 725 printk(KERN_WARNING "%s: Unable to generate code for " 726 "cipher [%s] with key bytes [%zd]\n", __func__, 727 mount_crypt_stat->global_default_fn_cipher_name, 728 mount_crypt_stat->global_default_fn_cipher_key_bytes); 729 rc = -EINVAL; 730 goto out_free_unlock; 731 } 732 dest[s->i++] = s->cipher_code; 733 /* TODO: Support other key modules than passphrase for 734 * filename encryption */ 735 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 736 rc = -EOPNOTSUPP; 737 printk(KERN_INFO "%s: Filename encryption only supports " 738 "password tokens\n", __func__); 739 goto out_free_unlock; 740 } 741 sg_init_one( 742 &s->hash_sg, 743 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 744 s->auth_tok->token.password.session_key_encryption_key_bytes); 745 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 746 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0, 747 CRYPTO_ALG_ASYNC); 748 if (IS_ERR(s->hash_desc.tfm)) { 749 rc = PTR_ERR(s->hash_desc.tfm); 750 printk(KERN_ERR "%s: Error attempting to " 751 "allocate hash crypto context; rc = [%d]\n", 752 __func__, rc); 753 goto out_free_unlock; 754 } 755 rc = crypto_hash_init(&s->hash_desc); 756 if (rc) { 757 printk(KERN_ERR 758 "%s: Error initializing crypto hash; rc = [%d]\n", 759 __func__, rc); 760 goto out_release_free_unlock; 761 } 762 rc = crypto_hash_update( 763 &s->hash_desc, &s->hash_sg, 764 s->auth_tok->token.password.session_key_encryption_key_bytes); 765 if (rc) { 766 printk(KERN_ERR 767 "%s: Error updating crypto hash; rc = [%d]\n", 768 __func__, rc); 769 goto out_release_free_unlock; 770 } 771 rc = crypto_hash_final(&s->hash_desc, s->hash); 772 if (rc) { 773 printk(KERN_ERR 774 "%s: Error finalizing crypto hash; rc = [%d]\n", 775 __func__, rc); 776 goto out_release_free_unlock; 777 } 778 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 779 s->block_aligned_filename[s->j] = 780 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 781 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 782 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 783 sg_init_one(&s->hash_sg, (u8 *)s->hash, 784 ECRYPTFS_TAG_70_DIGEST_SIZE); 785 rc = crypto_hash_init(&s->hash_desc); 786 if (rc) { 787 printk(KERN_ERR 788 "%s: Error initializing crypto hash; " 789 "rc = [%d]\n", __func__, rc); 790 goto out_release_free_unlock; 791 } 792 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg, 793 ECRYPTFS_TAG_70_DIGEST_SIZE); 794 if (rc) { 795 printk(KERN_ERR 796 "%s: Error updating crypto hash; " 797 "rc = [%d]\n", __func__, rc); 798 goto out_release_free_unlock; 799 } 800 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash); 801 if (rc) { 802 printk(KERN_ERR 803 "%s: Error finalizing crypto hash; " 804 "rc = [%d]\n", __func__, rc); 805 goto out_release_free_unlock; 806 } 807 memcpy(s->hash, s->tmp_hash, 808 ECRYPTFS_TAG_70_DIGEST_SIZE); 809 } 810 if (s->block_aligned_filename[s->j] == '\0') 811 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 812 } 813 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 814 filename_size); 815 rc = virt_to_scatterlist(s->block_aligned_filename, 816 s->block_aligned_filename_size, s->src_sg, 2); 817 if (rc < 1) { 818 printk(KERN_ERR "%s: Internal error whilst attempting to " 819 "convert filename memory to scatterlist; rc = [%d]. " 820 "block_aligned_filename_size = [%zd]\n", __func__, rc, 821 s->block_aligned_filename_size); 822 goto out_release_free_unlock; 823 } 824 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 825 s->dst_sg, 2); 826 if (rc < 1) { 827 printk(KERN_ERR "%s: Internal error whilst attempting to " 828 "convert encrypted filename memory to scatterlist; " 829 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 830 __func__, rc, s->block_aligned_filename_size); 831 goto out_release_free_unlock; 832 } 833 /* The characters in the first block effectively do the job 834 * of the IV here, so we just use 0's for the IV. Note the 835 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 836 * >= ECRYPTFS_MAX_IV_BYTES. */ 837 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 838 s->desc.info = s->iv; 839 rc = crypto_blkcipher_setkey( 840 s->desc.tfm, 841 s->auth_tok->token.password.session_key_encryption_key, 842 mount_crypt_stat->global_default_fn_cipher_key_bytes); 843 if (rc < 0) { 844 printk(KERN_ERR "%s: Error setting key for crypto context; " 845 "rc = [%d]. s->auth_tok->token.password.session_key_" 846 "encryption_key = [0x%p]; mount_crypt_stat->" 847 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 848 rc, 849 s->auth_tok->token.password.session_key_encryption_key, 850 mount_crypt_stat->global_default_fn_cipher_key_bytes); 851 goto out_release_free_unlock; 852 } 853 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg, 854 s->block_aligned_filename_size); 855 if (rc) { 856 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 857 "rc = [%d]\n", __func__, rc); 858 goto out_release_free_unlock; 859 } 860 s->i += s->block_aligned_filename_size; 861 (*packet_size) = s->i; 862 (*remaining_bytes) -= (*packet_size); 863 out_release_free_unlock: 864 crypto_free_hash(s->hash_desc.tfm); 865 out_free_unlock: 866 kzfree(s->block_aligned_filename); 867 out_unlock: 868 mutex_unlock(s->tfm_mutex); 869 out: 870 if (auth_tok_key) { 871 up_write(&(auth_tok_key->sem)); 872 key_put(auth_tok_key); 873 } 874 kfree(s); 875 return rc; 876 } 877 878 struct ecryptfs_parse_tag_70_packet_silly_stack { 879 u8 cipher_code; 880 size_t max_packet_size; 881 size_t packet_size_len; 882 size_t parsed_tag_70_packet_size; 883 size_t block_aligned_filename_size; 884 size_t block_size; 885 size_t i; 886 struct mutex *tfm_mutex; 887 char *decrypted_filename; 888 struct ecryptfs_auth_tok *auth_tok; 889 struct scatterlist src_sg[2]; 890 struct scatterlist dst_sg[2]; 891 struct blkcipher_desc desc; 892 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 893 char iv[ECRYPTFS_MAX_IV_BYTES]; 894 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE]; 895 }; 896 897 /** 898 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 899 * @filename: This function kmalloc's the memory for the filename 900 * @filename_size: This function sets this to the amount of memory 901 * kmalloc'd for the filename 902 * @packet_size: This function sets this to the the number of octets 903 * in the packet parsed 904 * @mount_crypt_stat: The mount-wide cryptographic context 905 * @data: The memory location containing the start of the tag 70 906 * packet 907 * @max_packet_size: The maximum legal size of the packet to be parsed 908 * from @data 909 * 910 * Returns zero on success; non-zero otherwise 911 */ 912 int 913 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 914 size_t *packet_size, 915 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 916 char *data, size_t max_packet_size) 917 { 918 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 919 struct key *auth_tok_key = NULL; 920 int rc = 0; 921 922 (*packet_size) = 0; 923 (*filename_size) = 0; 924 (*filename) = NULL; 925 s = kmalloc(sizeof(*s), GFP_KERNEL); 926 if (!s) { 927 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 928 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 929 rc = -ENOMEM; 930 goto out; 931 } 932 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 933 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 934 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 935 "at least [%d]\n", __func__, max_packet_size, 936 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 937 rc = -EINVAL; 938 goto out; 939 } 940 /* Octet 0: Tag 70 identifier 941 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 942 * and block-aligned encrypted filename size) 943 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 944 * Octet N2-N3: Cipher identifier (1 octet) 945 * Octets N3-N4: Block-aligned encrypted filename 946 * - Consists of a minimum number of random numbers, a \0 947 * separator, and then the filename */ 948 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 949 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 950 "tag [0x%.2x]\n", __func__, 951 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 952 rc = -EINVAL; 953 goto out; 954 } 955 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 956 &s->parsed_tag_70_packet_size, 957 &s->packet_size_len); 958 if (rc) { 959 printk(KERN_WARNING "%s: Error parsing packet length; " 960 "rc = [%d]\n", __func__, rc); 961 goto out; 962 } 963 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 964 - ECRYPTFS_SIG_SIZE - 1); 965 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 966 > max_packet_size) { 967 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 968 "size is [%zd]\n", __func__, max_packet_size, 969 (1 + s->packet_size_len + 1 970 + s->block_aligned_filename_size)); 971 rc = -EINVAL; 972 goto out; 973 } 974 (*packet_size) += s->packet_size_len; 975 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 976 ECRYPTFS_SIG_SIZE); 977 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 978 (*packet_size) += ECRYPTFS_SIG_SIZE; 979 s->cipher_code = data[(*packet_size)++]; 980 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 981 if (rc) { 982 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 983 __func__, s->cipher_code); 984 goto out; 985 } 986 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 987 &s->auth_tok, mount_crypt_stat, 988 s->fnek_sig_hex); 989 if (rc) { 990 printk(KERN_ERR "%s: Error attempting to find auth tok for " 991 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 992 rc); 993 goto out; 994 } 995 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm, 996 &s->tfm_mutex, 997 s->cipher_string); 998 if (unlikely(rc)) { 999 printk(KERN_ERR "Internal error whilst attempting to get " 1000 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1001 s->cipher_string, rc); 1002 goto out; 1003 } 1004 mutex_lock(s->tfm_mutex); 1005 rc = virt_to_scatterlist(&data[(*packet_size)], 1006 s->block_aligned_filename_size, s->src_sg, 2); 1007 if (rc < 1) { 1008 printk(KERN_ERR "%s: Internal error whilst attempting to " 1009 "convert encrypted filename memory to scatterlist; " 1010 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1011 __func__, rc, s->block_aligned_filename_size); 1012 goto out_unlock; 1013 } 1014 (*packet_size) += s->block_aligned_filename_size; 1015 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 1016 GFP_KERNEL); 1017 if (!s->decrypted_filename) { 1018 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1019 "kmalloc [%zd] bytes\n", __func__, 1020 s->block_aligned_filename_size); 1021 rc = -ENOMEM; 1022 goto out_unlock; 1023 } 1024 rc = virt_to_scatterlist(s->decrypted_filename, 1025 s->block_aligned_filename_size, s->dst_sg, 2); 1026 if (rc < 1) { 1027 printk(KERN_ERR "%s: Internal error whilst attempting to " 1028 "convert decrypted filename memory to scatterlist; " 1029 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1030 __func__, rc, s->block_aligned_filename_size); 1031 goto out_free_unlock; 1032 } 1033 /* The characters in the first block effectively do the job of 1034 * the IV here, so we just use 0's for the IV. Note the 1035 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1036 * >= ECRYPTFS_MAX_IV_BYTES. */ 1037 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 1038 s->desc.info = s->iv; 1039 /* TODO: Support other key modules than passphrase for 1040 * filename encryption */ 1041 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1042 rc = -EOPNOTSUPP; 1043 printk(KERN_INFO "%s: Filename encryption only supports " 1044 "password tokens\n", __func__); 1045 goto out_free_unlock; 1046 } 1047 rc = crypto_blkcipher_setkey( 1048 s->desc.tfm, 1049 s->auth_tok->token.password.session_key_encryption_key, 1050 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1051 if (rc < 0) { 1052 printk(KERN_ERR "%s: Error setting key for crypto context; " 1053 "rc = [%d]. s->auth_tok->token.password.session_key_" 1054 "encryption_key = [0x%p]; mount_crypt_stat->" 1055 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1056 rc, 1057 s->auth_tok->token.password.session_key_encryption_key, 1058 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1059 goto out_free_unlock; 1060 } 1061 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg, 1062 s->block_aligned_filename_size); 1063 if (rc) { 1064 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1065 "rc = [%d]\n", __func__, rc); 1066 goto out_free_unlock; 1067 } 1068 s->i = 0; 1069 while (s->decrypted_filename[s->i] != '\0' 1070 && s->i < s->block_aligned_filename_size) 1071 s->i++; 1072 if (s->i == s->block_aligned_filename_size) { 1073 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1074 "find valid separator between random characters and " 1075 "the filename\n", __func__); 1076 rc = -EINVAL; 1077 goto out_free_unlock; 1078 } 1079 s->i++; 1080 (*filename_size) = (s->block_aligned_filename_size - s->i); 1081 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1082 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1083 "invalid\n", __func__, (*filename_size)); 1084 rc = -EINVAL; 1085 goto out_free_unlock; 1086 } 1087 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1088 if (!(*filename)) { 1089 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1090 "kmalloc [%zd] bytes\n", __func__, 1091 ((*filename_size) + 1)); 1092 rc = -ENOMEM; 1093 goto out_free_unlock; 1094 } 1095 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1096 (*filename)[(*filename_size)] = '\0'; 1097 out_free_unlock: 1098 kfree(s->decrypted_filename); 1099 out_unlock: 1100 mutex_unlock(s->tfm_mutex); 1101 out: 1102 if (rc) { 1103 (*packet_size) = 0; 1104 (*filename_size) = 0; 1105 (*filename) = NULL; 1106 } 1107 if (auth_tok_key) { 1108 up_write(&(auth_tok_key->sem)); 1109 key_put(auth_tok_key); 1110 } 1111 kfree(s); 1112 return rc; 1113 } 1114 1115 static int 1116 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1117 { 1118 int rc = 0; 1119 1120 (*sig) = NULL; 1121 switch (auth_tok->token_type) { 1122 case ECRYPTFS_PASSWORD: 1123 (*sig) = auth_tok->token.password.signature; 1124 break; 1125 case ECRYPTFS_PRIVATE_KEY: 1126 (*sig) = auth_tok->token.private_key.signature; 1127 break; 1128 default: 1129 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1130 auth_tok->token_type); 1131 rc = -EINVAL; 1132 } 1133 return rc; 1134 } 1135 1136 /** 1137 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1138 * @auth_tok: The key authentication token used to decrypt the session key 1139 * @crypt_stat: The cryptographic context 1140 * 1141 * Returns zero on success; non-zero error otherwise. 1142 */ 1143 static int 1144 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1145 struct ecryptfs_crypt_stat *crypt_stat) 1146 { 1147 u8 cipher_code = 0; 1148 struct ecryptfs_msg_ctx *msg_ctx; 1149 struct ecryptfs_message *msg = NULL; 1150 char *auth_tok_sig; 1151 char *payload = NULL; 1152 size_t payload_len = 0; 1153 int rc; 1154 1155 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1156 if (rc) { 1157 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1158 auth_tok->token_type); 1159 goto out; 1160 } 1161 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1162 &payload, &payload_len); 1163 if (rc) { 1164 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1165 goto out; 1166 } 1167 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1168 if (rc) { 1169 ecryptfs_printk(KERN_ERR, "Error sending message to " 1170 "ecryptfsd: %d\n", rc); 1171 goto out; 1172 } 1173 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1174 if (rc) { 1175 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1176 "from the user space daemon\n"); 1177 rc = -EIO; 1178 goto out; 1179 } 1180 rc = parse_tag_65_packet(&(auth_tok->session_key), 1181 &cipher_code, msg); 1182 if (rc) { 1183 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1184 rc); 1185 goto out; 1186 } 1187 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1188 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1189 auth_tok->session_key.decrypted_key_size); 1190 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1191 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1192 if (rc) { 1193 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1194 cipher_code) 1195 goto out; 1196 } 1197 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1198 if (ecryptfs_verbosity > 0) { 1199 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1200 ecryptfs_dump_hex(crypt_stat->key, 1201 crypt_stat->key_size); 1202 } 1203 out: 1204 kfree(msg); 1205 kfree(payload); 1206 return rc; 1207 } 1208 1209 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1210 { 1211 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1212 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1213 1214 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1215 auth_tok_list_head, list) { 1216 list_del(&auth_tok_list_item->list); 1217 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1218 auth_tok_list_item); 1219 } 1220 } 1221 1222 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1223 1224 /** 1225 * parse_tag_1_packet 1226 * @crypt_stat: The cryptographic context to modify based on packet contents 1227 * @data: The raw bytes of the packet. 1228 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1229 * a new authentication token will be placed at the 1230 * end of this list for this packet. 1231 * @new_auth_tok: Pointer to a pointer to memory that this function 1232 * allocates; sets the memory address of the pointer to 1233 * NULL on error. This object is added to the 1234 * auth_tok_list. 1235 * @packet_size: This function writes the size of the parsed packet 1236 * into this memory location; zero on error. 1237 * @max_packet_size: The maximum allowable packet size 1238 * 1239 * Returns zero on success; non-zero on error. 1240 */ 1241 static int 1242 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1243 unsigned char *data, struct list_head *auth_tok_list, 1244 struct ecryptfs_auth_tok **new_auth_tok, 1245 size_t *packet_size, size_t max_packet_size) 1246 { 1247 size_t body_size; 1248 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1249 size_t length_size; 1250 int rc = 0; 1251 1252 (*packet_size) = 0; 1253 (*new_auth_tok) = NULL; 1254 /** 1255 * This format is inspired by OpenPGP; see RFC 2440 1256 * packet tag 1 1257 * 1258 * Tag 1 identifier (1 byte) 1259 * Max Tag 1 packet size (max 3 bytes) 1260 * Version (1 byte) 1261 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1262 * Cipher identifier (1 byte) 1263 * Encrypted key size (arbitrary) 1264 * 1265 * 12 bytes minimum packet size 1266 */ 1267 if (unlikely(max_packet_size < 12)) { 1268 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1269 rc = -EINVAL; 1270 goto out; 1271 } 1272 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1273 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1274 ECRYPTFS_TAG_1_PACKET_TYPE); 1275 rc = -EINVAL; 1276 goto out; 1277 } 1278 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1279 * at end of function upon failure */ 1280 auth_tok_list_item = 1281 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1282 GFP_KERNEL); 1283 if (!auth_tok_list_item) { 1284 printk(KERN_ERR "Unable to allocate memory\n"); 1285 rc = -ENOMEM; 1286 goto out; 1287 } 1288 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1289 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1290 &length_size); 1291 if (rc) { 1292 printk(KERN_WARNING "Error parsing packet length; " 1293 "rc = [%d]\n", rc); 1294 goto out_free; 1295 } 1296 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1297 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1298 rc = -EINVAL; 1299 goto out_free; 1300 } 1301 (*packet_size) += length_size; 1302 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1303 printk(KERN_WARNING "Packet size exceeds max\n"); 1304 rc = -EINVAL; 1305 goto out_free; 1306 } 1307 if (unlikely(data[(*packet_size)++] != 0x03)) { 1308 printk(KERN_WARNING "Unknown version number [%d]\n", 1309 data[(*packet_size) - 1]); 1310 rc = -EINVAL; 1311 goto out_free; 1312 } 1313 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1314 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1315 *packet_size += ECRYPTFS_SIG_SIZE; 1316 /* This byte is skipped because the kernel does not need to 1317 * know which public key encryption algorithm was used */ 1318 (*packet_size)++; 1319 (*new_auth_tok)->session_key.encrypted_key_size = 1320 body_size - (ECRYPTFS_SIG_SIZE + 2); 1321 if ((*new_auth_tok)->session_key.encrypted_key_size 1322 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1323 printk(KERN_WARNING "Tag 1 packet contains key larger " 1324 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); 1325 rc = -EINVAL; 1326 goto out; 1327 } 1328 memcpy((*new_auth_tok)->session_key.encrypted_key, 1329 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1330 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1331 (*new_auth_tok)->session_key.flags &= 1332 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1333 (*new_auth_tok)->session_key.flags |= 1334 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1335 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1336 (*new_auth_tok)->flags = 0; 1337 (*new_auth_tok)->session_key.flags &= 1338 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1339 (*new_auth_tok)->session_key.flags &= 1340 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1341 list_add(&auth_tok_list_item->list, auth_tok_list); 1342 goto out; 1343 out_free: 1344 (*new_auth_tok) = NULL; 1345 memset(auth_tok_list_item, 0, 1346 sizeof(struct ecryptfs_auth_tok_list_item)); 1347 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1348 auth_tok_list_item); 1349 out: 1350 if (rc) 1351 (*packet_size) = 0; 1352 return rc; 1353 } 1354 1355 /** 1356 * parse_tag_3_packet 1357 * @crypt_stat: The cryptographic context to modify based on packet 1358 * contents. 1359 * @data: The raw bytes of the packet. 1360 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1361 * a new authentication token will be placed at the end 1362 * of this list for this packet. 1363 * @new_auth_tok: Pointer to a pointer to memory that this function 1364 * allocates; sets the memory address of the pointer to 1365 * NULL on error. This object is added to the 1366 * auth_tok_list. 1367 * @packet_size: This function writes the size of the parsed packet 1368 * into this memory location; zero on error. 1369 * @max_packet_size: maximum number of bytes to parse 1370 * 1371 * Returns zero on success; non-zero on error. 1372 */ 1373 static int 1374 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1375 unsigned char *data, struct list_head *auth_tok_list, 1376 struct ecryptfs_auth_tok **new_auth_tok, 1377 size_t *packet_size, size_t max_packet_size) 1378 { 1379 size_t body_size; 1380 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1381 size_t length_size; 1382 int rc = 0; 1383 1384 (*packet_size) = 0; 1385 (*new_auth_tok) = NULL; 1386 /** 1387 *This format is inspired by OpenPGP; see RFC 2440 1388 * packet tag 3 1389 * 1390 * Tag 3 identifier (1 byte) 1391 * Max Tag 3 packet size (max 3 bytes) 1392 * Version (1 byte) 1393 * Cipher code (1 byte) 1394 * S2K specifier (1 byte) 1395 * Hash identifier (1 byte) 1396 * Salt (ECRYPTFS_SALT_SIZE) 1397 * Hash iterations (1 byte) 1398 * Encrypted key (arbitrary) 1399 * 1400 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1401 */ 1402 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1403 printk(KERN_ERR "Max packet size too large\n"); 1404 rc = -EINVAL; 1405 goto out; 1406 } 1407 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1408 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1409 ECRYPTFS_TAG_3_PACKET_TYPE); 1410 rc = -EINVAL; 1411 goto out; 1412 } 1413 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1414 * at end of function upon failure */ 1415 auth_tok_list_item = 1416 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1417 if (!auth_tok_list_item) { 1418 printk(KERN_ERR "Unable to allocate memory\n"); 1419 rc = -ENOMEM; 1420 goto out; 1421 } 1422 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1423 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1424 &length_size); 1425 if (rc) { 1426 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1427 rc); 1428 goto out_free; 1429 } 1430 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1431 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1432 rc = -EINVAL; 1433 goto out_free; 1434 } 1435 (*packet_size) += length_size; 1436 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1437 printk(KERN_ERR "Packet size exceeds max\n"); 1438 rc = -EINVAL; 1439 goto out_free; 1440 } 1441 (*new_auth_tok)->session_key.encrypted_key_size = 1442 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1443 if ((*new_auth_tok)->session_key.encrypted_key_size 1444 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1445 printk(KERN_WARNING "Tag 3 packet contains key larger " 1446 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1447 rc = -EINVAL; 1448 goto out_free; 1449 } 1450 if (unlikely(data[(*packet_size)++] != 0x04)) { 1451 printk(KERN_WARNING "Unknown version number [%d]\n", 1452 data[(*packet_size) - 1]); 1453 rc = -EINVAL; 1454 goto out_free; 1455 } 1456 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1457 (u16)data[(*packet_size)]); 1458 if (rc) 1459 goto out_free; 1460 /* A little extra work to differentiate among the AES key 1461 * sizes; see RFC2440 */ 1462 switch(data[(*packet_size)++]) { 1463 case RFC2440_CIPHER_AES_192: 1464 crypt_stat->key_size = 24; 1465 break; 1466 default: 1467 crypt_stat->key_size = 1468 (*new_auth_tok)->session_key.encrypted_key_size; 1469 } 1470 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1471 if (rc) 1472 goto out_free; 1473 if (unlikely(data[(*packet_size)++] != 0x03)) { 1474 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1475 rc = -ENOSYS; 1476 goto out_free; 1477 } 1478 /* TODO: finish the hash mapping */ 1479 switch (data[(*packet_size)++]) { 1480 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1481 /* Choose MD5 */ 1482 memcpy((*new_auth_tok)->token.password.salt, 1483 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1484 (*packet_size) += ECRYPTFS_SALT_SIZE; 1485 /* This conversion was taken straight from RFC2440 */ 1486 (*new_auth_tok)->token.password.hash_iterations = 1487 ((u32) 16 + (data[(*packet_size)] & 15)) 1488 << ((data[(*packet_size)] >> 4) + 6); 1489 (*packet_size)++; 1490 /* Friendly reminder: 1491 * (*new_auth_tok)->session_key.encrypted_key_size = 1492 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1493 memcpy((*new_auth_tok)->session_key.encrypted_key, 1494 &data[(*packet_size)], 1495 (*new_auth_tok)->session_key.encrypted_key_size); 1496 (*packet_size) += 1497 (*new_auth_tok)->session_key.encrypted_key_size; 1498 (*new_auth_tok)->session_key.flags &= 1499 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1500 (*new_auth_tok)->session_key.flags |= 1501 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1502 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1503 break; 1504 default: 1505 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1506 "[%d]\n", data[(*packet_size) - 1]); 1507 rc = -ENOSYS; 1508 goto out_free; 1509 } 1510 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1511 /* TODO: Parametarize; we might actually want userspace to 1512 * decrypt the session key. */ 1513 (*new_auth_tok)->session_key.flags &= 1514 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1515 (*new_auth_tok)->session_key.flags &= 1516 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1517 list_add(&auth_tok_list_item->list, auth_tok_list); 1518 goto out; 1519 out_free: 1520 (*new_auth_tok) = NULL; 1521 memset(auth_tok_list_item, 0, 1522 sizeof(struct ecryptfs_auth_tok_list_item)); 1523 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1524 auth_tok_list_item); 1525 out: 1526 if (rc) 1527 (*packet_size) = 0; 1528 return rc; 1529 } 1530 1531 /** 1532 * parse_tag_11_packet 1533 * @data: The raw bytes of the packet 1534 * @contents: This function writes the data contents of the literal 1535 * packet into this memory location 1536 * @max_contents_bytes: The maximum number of bytes that this function 1537 * is allowed to write into contents 1538 * @tag_11_contents_size: This function writes the size of the parsed 1539 * contents into this memory location; zero on 1540 * error 1541 * @packet_size: This function writes the size of the parsed packet 1542 * into this memory location; zero on error 1543 * @max_packet_size: maximum number of bytes to parse 1544 * 1545 * Returns zero on success; non-zero on error. 1546 */ 1547 static int 1548 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1549 size_t max_contents_bytes, size_t *tag_11_contents_size, 1550 size_t *packet_size, size_t max_packet_size) 1551 { 1552 size_t body_size; 1553 size_t length_size; 1554 int rc = 0; 1555 1556 (*packet_size) = 0; 1557 (*tag_11_contents_size) = 0; 1558 /* This format is inspired by OpenPGP; see RFC 2440 1559 * packet tag 11 1560 * 1561 * Tag 11 identifier (1 byte) 1562 * Max Tag 11 packet size (max 3 bytes) 1563 * Binary format specifier (1 byte) 1564 * Filename length (1 byte) 1565 * Filename ("_CONSOLE") (8 bytes) 1566 * Modification date (4 bytes) 1567 * Literal data (arbitrary) 1568 * 1569 * We need at least 16 bytes of data for the packet to even be 1570 * valid. 1571 */ 1572 if (max_packet_size < 16) { 1573 printk(KERN_ERR "Maximum packet size too small\n"); 1574 rc = -EINVAL; 1575 goto out; 1576 } 1577 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1578 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1579 rc = -EINVAL; 1580 goto out; 1581 } 1582 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1583 &length_size); 1584 if (rc) { 1585 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1586 goto out; 1587 } 1588 if (body_size < 14) { 1589 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1590 rc = -EINVAL; 1591 goto out; 1592 } 1593 (*packet_size) += length_size; 1594 (*tag_11_contents_size) = (body_size - 14); 1595 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1596 printk(KERN_ERR "Packet size exceeds max\n"); 1597 rc = -EINVAL; 1598 goto out; 1599 } 1600 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1601 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1602 "expected size\n"); 1603 rc = -EINVAL; 1604 goto out; 1605 } 1606 if (data[(*packet_size)++] != 0x62) { 1607 printk(KERN_WARNING "Unrecognizable packet\n"); 1608 rc = -EINVAL; 1609 goto out; 1610 } 1611 if (data[(*packet_size)++] != 0x08) { 1612 printk(KERN_WARNING "Unrecognizable packet\n"); 1613 rc = -EINVAL; 1614 goto out; 1615 } 1616 (*packet_size) += 12; /* Ignore filename and modification date */ 1617 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1618 (*packet_size) += (*tag_11_contents_size); 1619 out: 1620 if (rc) { 1621 (*packet_size) = 0; 1622 (*tag_11_contents_size) = 0; 1623 } 1624 return rc; 1625 } 1626 1627 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1628 struct ecryptfs_auth_tok **auth_tok, 1629 char *sig) 1630 { 1631 int rc = 0; 1632 1633 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1634 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1635 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1636 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1637 printk(KERN_ERR "Could not find key with description: [%s]\n", 1638 sig); 1639 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1640 (*auth_tok_key) = NULL; 1641 goto out; 1642 } 1643 } 1644 down_write(&(*auth_tok_key)->sem); 1645 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1646 if (rc) { 1647 up_write(&(*auth_tok_key)->sem); 1648 key_put(*auth_tok_key); 1649 (*auth_tok_key) = NULL; 1650 goto out; 1651 } 1652 out: 1653 return rc; 1654 } 1655 1656 /** 1657 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1658 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1659 * @crypt_stat: The cryptographic context 1660 * 1661 * Returns zero on success; non-zero error otherwise 1662 */ 1663 static int 1664 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1665 struct ecryptfs_crypt_stat *crypt_stat) 1666 { 1667 struct scatterlist dst_sg[2]; 1668 struct scatterlist src_sg[2]; 1669 struct mutex *tfm_mutex; 1670 struct blkcipher_desc desc = { 1671 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 1672 }; 1673 int rc = 0; 1674 1675 if (unlikely(ecryptfs_verbosity > 0)) { 1676 ecryptfs_printk( 1677 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1678 auth_tok->token.password.session_key_encryption_key_bytes); 1679 ecryptfs_dump_hex( 1680 auth_tok->token.password.session_key_encryption_key, 1681 auth_tok->token.password.session_key_encryption_key_bytes); 1682 } 1683 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 1684 crypt_stat->cipher); 1685 if (unlikely(rc)) { 1686 printk(KERN_ERR "Internal error whilst attempting to get " 1687 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1688 crypt_stat->cipher, rc); 1689 goto out; 1690 } 1691 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1692 auth_tok->session_key.encrypted_key_size, 1693 src_sg, 2); 1694 if (rc < 1 || rc > 2) { 1695 printk(KERN_ERR "Internal error whilst attempting to convert " 1696 "auth_tok->session_key.encrypted_key to scatterlist; " 1697 "expected rc = 1; got rc = [%d]. " 1698 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1699 auth_tok->session_key.encrypted_key_size); 1700 goto out; 1701 } 1702 auth_tok->session_key.decrypted_key_size = 1703 auth_tok->session_key.encrypted_key_size; 1704 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1705 auth_tok->session_key.decrypted_key_size, 1706 dst_sg, 2); 1707 if (rc < 1 || rc > 2) { 1708 printk(KERN_ERR "Internal error whilst attempting to convert " 1709 "auth_tok->session_key.decrypted_key to scatterlist; " 1710 "expected rc = 1; got rc = [%d]\n", rc); 1711 goto out; 1712 } 1713 mutex_lock(tfm_mutex); 1714 rc = crypto_blkcipher_setkey( 1715 desc.tfm, auth_tok->token.password.session_key_encryption_key, 1716 crypt_stat->key_size); 1717 if (unlikely(rc < 0)) { 1718 mutex_unlock(tfm_mutex); 1719 printk(KERN_ERR "Error setting key for crypto context\n"); 1720 rc = -EINVAL; 1721 goto out; 1722 } 1723 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg, 1724 auth_tok->session_key.encrypted_key_size); 1725 mutex_unlock(tfm_mutex); 1726 if (unlikely(rc)) { 1727 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1728 goto out; 1729 } 1730 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1731 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1732 auth_tok->session_key.decrypted_key_size); 1733 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1734 if (unlikely(ecryptfs_verbosity > 0)) { 1735 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1736 crypt_stat->key_size); 1737 ecryptfs_dump_hex(crypt_stat->key, 1738 crypt_stat->key_size); 1739 } 1740 out: 1741 return rc; 1742 } 1743 1744 /** 1745 * ecryptfs_parse_packet_set 1746 * @crypt_stat: The cryptographic context 1747 * @src: Virtual address of region of memory containing the packets 1748 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1749 * 1750 * Get crypt_stat to have the file's session key if the requisite key 1751 * is available to decrypt the session key. 1752 * 1753 * Returns Zero if a valid authentication token was retrieved and 1754 * processed; negative value for file not encrypted or for error 1755 * conditions. 1756 */ 1757 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1758 unsigned char *src, 1759 struct dentry *ecryptfs_dentry) 1760 { 1761 size_t i = 0; 1762 size_t found_auth_tok; 1763 size_t next_packet_is_auth_tok_packet; 1764 struct list_head auth_tok_list; 1765 struct ecryptfs_auth_tok *matching_auth_tok; 1766 struct ecryptfs_auth_tok *candidate_auth_tok; 1767 char *candidate_auth_tok_sig; 1768 size_t packet_size; 1769 struct ecryptfs_auth_tok *new_auth_tok; 1770 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1771 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1772 size_t tag_11_contents_size; 1773 size_t tag_11_packet_size; 1774 struct key *auth_tok_key = NULL; 1775 int rc = 0; 1776 1777 INIT_LIST_HEAD(&auth_tok_list); 1778 /* Parse the header to find as many packets as we can; these will be 1779 * added the our &auth_tok_list */ 1780 next_packet_is_auth_tok_packet = 1; 1781 while (next_packet_is_auth_tok_packet) { 1782 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i); 1783 1784 switch (src[i]) { 1785 case ECRYPTFS_TAG_3_PACKET_TYPE: 1786 rc = parse_tag_3_packet(crypt_stat, 1787 (unsigned char *)&src[i], 1788 &auth_tok_list, &new_auth_tok, 1789 &packet_size, max_packet_size); 1790 if (rc) { 1791 ecryptfs_printk(KERN_ERR, "Error parsing " 1792 "tag 3 packet\n"); 1793 rc = -EIO; 1794 goto out_wipe_list; 1795 } 1796 i += packet_size; 1797 rc = parse_tag_11_packet((unsigned char *)&src[i], 1798 sig_tmp_space, 1799 ECRYPTFS_SIG_SIZE, 1800 &tag_11_contents_size, 1801 &tag_11_packet_size, 1802 max_packet_size); 1803 if (rc) { 1804 ecryptfs_printk(KERN_ERR, "No valid " 1805 "(ecryptfs-specific) literal " 1806 "packet containing " 1807 "authentication token " 1808 "signature found after " 1809 "tag 3 packet\n"); 1810 rc = -EIO; 1811 goto out_wipe_list; 1812 } 1813 i += tag_11_packet_size; 1814 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1815 ecryptfs_printk(KERN_ERR, "Expected " 1816 "signature of size [%d]; " 1817 "read size [%zd]\n", 1818 ECRYPTFS_SIG_SIZE, 1819 tag_11_contents_size); 1820 rc = -EIO; 1821 goto out_wipe_list; 1822 } 1823 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1824 sig_tmp_space, tag_11_contents_size); 1825 new_auth_tok->token.password.signature[ 1826 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1827 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1828 break; 1829 case ECRYPTFS_TAG_1_PACKET_TYPE: 1830 rc = parse_tag_1_packet(crypt_stat, 1831 (unsigned char *)&src[i], 1832 &auth_tok_list, &new_auth_tok, 1833 &packet_size, max_packet_size); 1834 if (rc) { 1835 ecryptfs_printk(KERN_ERR, "Error parsing " 1836 "tag 1 packet\n"); 1837 rc = -EIO; 1838 goto out_wipe_list; 1839 } 1840 i += packet_size; 1841 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1842 break; 1843 case ECRYPTFS_TAG_11_PACKET_TYPE: 1844 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1845 "(Tag 11 not allowed by itself)\n"); 1846 rc = -EIO; 1847 goto out_wipe_list; 1848 default: 1849 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1850 "of the file header; hex value of " 1851 "character is [0x%.2x]\n", i, src[i]); 1852 next_packet_is_auth_tok_packet = 0; 1853 } 1854 } 1855 if (list_empty(&auth_tok_list)) { 1856 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1857 "eCryptfs file; this is not supported in this version " 1858 "of the eCryptfs kernel module\n"); 1859 rc = -EINVAL; 1860 goto out; 1861 } 1862 /* auth_tok_list contains the set of authentication tokens 1863 * parsed from the metadata. We need to find a matching 1864 * authentication token that has the secret component(s) 1865 * necessary to decrypt the EFEK in the auth_tok parsed from 1866 * the metadata. There may be several potential matches, but 1867 * just one will be sufficient to decrypt to get the FEK. */ 1868 find_next_matching_auth_tok: 1869 found_auth_tok = 0; 1870 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1871 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1872 if (unlikely(ecryptfs_verbosity > 0)) { 1873 ecryptfs_printk(KERN_DEBUG, 1874 "Considering cadidate auth tok:\n"); 1875 ecryptfs_dump_auth_tok(candidate_auth_tok); 1876 } 1877 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1878 candidate_auth_tok); 1879 if (rc) { 1880 printk(KERN_ERR 1881 "Unrecognized candidate auth tok type: [%d]\n", 1882 candidate_auth_tok->token_type); 1883 rc = -EINVAL; 1884 goto out_wipe_list; 1885 } 1886 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1887 &matching_auth_tok, 1888 crypt_stat->mount_crypt_stat, 1889 candidate_auth_tok_sig); 1890 if (!rc) { 1891 found_auth_tok = 1; 1892 goto found_matching_auth_tok; 1893 } 1894 } 1895 if (!found_auth_tok) { 1896 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1897 "authentication token\n"); 1898 rc = -EIO; 1899 goto out_wipe_list; 1900 } 1901 found_matching_auth_tok: 1902 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1903 memcpy(&(candidate_auth_tok->token.private_key), 1904 &(matching_auth_tok->token.private_key), 1905 sizeof(struct ecryptfs_private_key)); 1906 up_write(&(auth_tok_key->sem)); 1907 key_put(auth_tok_key); 1908 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1909 crypt_stat); 1910 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1911 memcpy(&(candidate_auth_tok->token.password), 1912 &(matching_auth_tok->token.password), 1913 sizeof(struct ecryptfs_password)); 1914 up_write(&(auth_tok_key->sem)); 1915 key_put(auth_tok_key); 1916 rc = decrypt_passphrase_encrypted_session_key( 1917 candidate_auth_tok, crypt_stat); 1918 } else { 1919 up_write(&(auth_tok_key->sem)); 1920 key_put(auth_tok_key); 1921 rc = -EINVAL; 1922 } 1923 if (rc) { 1924 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1925 1926 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1927 "session key for authentication token with sig " 1928 "[%.*s]; rc = [%d]. Removing auth tok " 1929 "candidate from the list and searching for " 1930 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1931 candidate_auth_tok_sig, rc); 1932 list_for_each_entry_safe(auth_tok_list_item, 1933 auth_tok_list_item_tmp, 1934 &auth_tok_list, list) { 1935 if (candidate_auth_tok 1936 == &auth_tok_list_item->auth_tok) { 1937 list_del(&auth_tok_list_item->list); 1938 kmem_cache_free( 1939 ecryptfs_auth_tok_list_item_cache, 1940 auth_tok_list_item); 1941 goto find_next_matching_auth_tok; 1942 } 1943 } 1944 BUG(); 1945 } 1946 rc = ecryptfs_compute_root_iv(crypt_stat); 1947 if (rc) { 1948 ecryptfs_printk(KERN_ERR, "Error computing " 1949 "the root IV\n"); 1950 goto out_wipe_list; 1951 } 1952 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1953 if (rc) { 1954 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1955 "context for cipher [%s]; rc = [%d]\n", 1956 crypt_stat->cipher, rc); 1957 } 1958 out_wipe_list: 1959 wipe_auth_tok_list(&auth_tok_list); 1960 out: 1961 return rc; 1962 } 1963 1964 static int 1965 pki_encrypt_session_key(struct key *auth_tok_key, 1966 struct ecryptfs_auth_tok *auth_tok, 1967 struct ecryptfs_crypt_stat *crypt_stat, 1968 struct ecryptfs_key_record *key_rec) 1969 { 1970 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1971 char *payload = NULL; 1972 size_t payload_len = 0; 1973 struct ecryptfs_message *msg; 1974 int rc; 1975 1976 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1977 ecryptfs_code_for_cipher_string( 1978 crypt_stat->cipher, 1979 crypt_stat->key_size), 1980 crypt_stat, &payload, &payload_len); 1981 up_write(&(auth_tok_key->sem)); 1982 key_put(auth_tok_key); 1983 if (rc) { 1984 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1985 goto out; 1986 } 1987 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1988 if (rc) { 1989 ecryptfs_printk(KERN_ERR, "Error sending message to " 1990 "ecryptfsd: %d\n", rc); 1991 goto out; 1992 } 1993 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1994 if (rc) { 1995 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 1996 "from the user space daemon\n"); 1997 rc = -EIO; 1998 goto out; 1999 } 2000 rc = parse_tag_67_packet(key_rec, msg); 2001 if (rc) 2002 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2003 kfree(msg); 2004 out: 2005 kfree(payload); 2006 return rc; 2007 } 2008 /** 2009 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2010 * @dest: Buffer into which to write the packet 2011 * @remaining_bytes: Maximum number of bytes that can be writtn 2012 * @auth_tok_key: The authentication token key to unlock and put when done with 2013 * @auth_tok 2014 * @auth_tok: The authentication token used for generating the tag 1 packet 2015 * @crypt_stat: The cryptographic context 2016 * @key_rec: The key record struct for the tag 1 packet 2017 * @packet_size: This function will write the number of bytes that end 2018 * up constituting the packet; set to zero on error 2019 * 2020 * Returns zero on success; non-zero on error. 2021 */ 2022 static int 2023 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2024 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2025 struct ecryptfs_crypt_stat *crypt_stat, 2026 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2027 { 2028 size_t i; 2029 size_t encrypted_session_key_valid = 0; 2030 size_t packet_size_length; 2031 size_t max_packet_size; 2032 int rc = 0; 2033 2034 (*packet_size) = 0; 2035 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2036 ECRYPTFS_SIG_SIZE); 2037 encrypted_session_key_valid = 0; 2038 for (i = 0; i < crypt_stat->key_size; i++) 2039 encrypted_session_key_valid |= 2040 auth_tok->session_key.encrypted_key[i]; 2041 if (encrypted_session_key_valid) { 2042 memcpy(key_rec->enc_key, 2043 auth_tok->session_key.encrypted_key, 2044 auth_tok->session_key.encrypted_key_size); 2045 up_write(&(auth_tok_key->sem)); 2046 key_put(auth_tok_key); 2047 goto encrypted_session_key_set; 2048 } 2049 if (auth_tok->session_key.encrypted_key_size == 0) 2050 auth_tok->session_key.encrypted_key_size = 2051 auth_tok->token.private_key.key_size; 2052 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2053 key_rec); 2054 if (rc) { 2055 printk(KERN_ERR "Failed to encrypt session key via a key " 2056 "module; rc = [%d]\n", rc); 2057 goto out; 2058 } 2059 if (ecryptfs_verbosity > 0) { 2060 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2061 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2062 } 2063 encrypted_session_key_set: 2064 /* This format is inspired by OpenPGP; see RFC 2440 2065 * packet tag 1 */ 2066 max_packet_size = (1 /* Tag 1 identifier */ 2067 + 3 /* Max Tag 1 packet size */ 2068 + 1 /* Version */ 2069 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2070 + 1 /* Cipher identifier */ 2071 + key_rec->enc_key_size); /* Encrypted key size */ 2072 if (max_packet_size > (*remaining_bytes)) { 2073 printk(KERN_ERR "Packet length larger than maximum allowable; " 2074 "need up to [%td] bytes, but there are only [%td] " 2075 "available\n", max_packet_size, (*remaining_bytes)); 2076 rc = -EINVAL; 2077 goto out; 2078 } 2079 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2080 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2081 (max_packet_size - 4), 2082 &packet_size_length); 2083 if (rc) { 2084 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2085 "header; cannot generate packet length\n"); 2086 goto out; 2087 } 2088 (*packet_size) += packet_size_length; 2089 dest[(*packet_size)++] = 0x03; /* version 3 */ 2090 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2091 (*packet_size) += ECRYPTFS_SIG_SIZE; 2092 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2093 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2094 key_rec->enc_key_size); 2095 (*packet_size) += key_rec->enc_key_size; 2096 out: 2097 if (rc) 2098 (*packet_size) = 0; 2099 else 2100 (*remaining_bytes) -= (*packet_size); 2101 return rc; 2102 } 2103 2104 /** 2105 * write_tag_11_packet 2106 * @dest: Target into which Tag 11 packet is to be written 2107 * @remaining_bytes: Maximum packet length 2108 * @contents: Byte array of contents to copy in 2109 * @contents_length: Number of bytes in contents 2110 * @packet_length: Length of the Tag 11 packet written; zero on error 2111 * 2112 * Returns zero on success; non-zero on error. 2113 */ 2114 static int 2115 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2116 size_t contents_length, size_t *packet_length) 2117 { 2118 size_t packet_size_length; 2119 size_t max_packet_size; 2120 int rc = 0; 2121 2122 (*packet_length) = 0; 2123 /* This format is inspired by OpenPGP; see RFC 2440 2124 * packet tag 11 */ 2125 max_packet_size = (1 /* Tag 11 identifier */ 2126 + 3 /* Max Tag 11 packet size */ 2127 + 1 /* Binary format specifier */ 2128 + 1 /* Filename length */ 2129 + 8 /* Filename ("_CONSOLE") */ 2130 + 4 /* Modification date */ 2131 + contents_length); /* Literal data */ 2132 if (max_packet_size > (*remaining_bytes)) { 2133 printk(KERN_ERR "Packet length larger than maximum allowable; " 2134 "need up to [%td] bytes, but there are only [%td] " 2135 "available\n", max_packet_size, (*remaining_bytes)); 2136 rc = -EINVAL; 2137 goto out; 2138 } 2139 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2140 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2141 (max_packet_size - 4), 2142 &packet_size_length); 2143 if (rc) { 2144 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2145 "generate packet length. rc = [%d]\n", rc); 2146 goto out; 2147 } 2148 (*packet_length) += packet_size_length; 2149 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2150 dest[(*packet_length)++] = 8; 2151 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2152 (*packet_length) += 8; 2153 memset(&dest[(*packet_length)], 0x00, 4); 2154 (*packet_length) += 4; 2155 memcpy(&dest[(*packet_length)], contents, contents_length); 2156 (*packet_length) += contents_length; 2157 out: 2158 if (rc) 2159 (*packet_length) = 0; 2160 else 2161 (*remaining_bytes) -= (*packet_length); 2162 return rc; 2163 } 2164 2165 /** 2166 * write_tag_3_packet 2167 * @dest: Buffer into which to write the packet 2168 * @remaining_bytes: Maximum number of bytes that can be written 2169 * @auth_tok: Authentication token 2170 * @crypt_stat: The cryptographic context 2171 * @key_rec: encrypted key 2172 * @packet_size: This function will write the number of bytes that end 2173 * up constituting the packet; set to zero on error 2174 * 2175 * Returns zero on success; non-zero on error. 2176 */ 2177 static int 2178 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2179 struct ecryptfs_auth_tok *auth_tok, 2180 struct ecryptfs_crypt_stat *crypt_stat, 2181 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2182 { 2183 size_t i; 2184 size_t encrypted_session_key_valid = 0; 2185 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2186 struct scatterlist dst_sg[2]; 2187 struct scatterlist src_sg[2]; 2188 struct mutex *tfm_mutex = NULL; 2189 u8 cipher_code; 2190 size_t packet_size_length; 2191 size_t max_packet_size; 2192 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2193 crypt_stat->mount_crypt_stat; 2194 struct blkcipher_desc desc = { 2195 .tfm = NULL, 2196 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 2197 }; 2198 int rc = 0; 2199 2200 (*packet_size) = 0; 2201 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2202 ECRYPTFS_SIG_SIZE); 2203 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 2204 crypt_stat->cipher); 2205 if (unlikely(rc)) { 2206 printk(KERN_ERR "Internal error whilst attempting to get " 2207 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2208 crypt_stat->cipher, rc); 2209 goto out; 2210 } 2211 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2212 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm); 2213 2214 printk(KERN_WARNING "No key size specified at mount; " 2215 "defaulting to [%d]\n", alg->max_keysize); 2216 mount_crypt_stat->global_default_cipher_key_size = 2217 alg->max_keysize; 2218 } 2219 if (crypt_stat->key_size == 0) 2220 crypt_stat->key_size = 2221 mount_crypt_stat->global_default_cipher_key_size; 2222 if (auth_tok->session_key.encrypted_key_size == 0) 2223 auth_tok->session_key.encrypted_key_size = 2224 crypt_stat->key_size; 2225 if (crypt_stat->key_size == 24 2226 && strcmp("aes", crypt_stat->cipher) == 0) { 2227 memset((crypt_stat->key + 24), 0, 8); 2228 auth_tok->session_key.encrypted_key_size = 32; 2229 } else 2230 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2231 key_rec->enc_key_size = 2232 auth_tok->session_key.encrypted_key_size; 2233 encrypted_session_key_valid = 0; 2234 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2235 encrypted_session_key_valid |= 2236 auth_tok->session_key.encrypted_key[i]; 2237 if (encrypted_session_key_valid) { 2238 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2239 "using auth_tok->session_key.encrypted_key, " 2240 "where key_rec->enc_key_size = [%zd]\n", 2241 key_rec->enc_key_size); 2242 memcpy(key_rec->enc_key, 2243 auth_tok->session_key.encrypted_key, 2244 key_rec->enc_key_size); 2245 goto encrypted_session_key_set; 2246 } 2247 if (auth_tok->token.password.flags & 2248 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2249 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2250 "session key encryption key of size [%d]\n", 2251 auth_tok->token.password. 2252 session_key_encryption_key_bytes); 2253 memcpy(session_key_encryption_key, 2254 auth_tok->token.password.session_key_encryption_key, 2255 crypt_stat->key_size); 2256 ecryptfs_printk(KERN_DEBUG, 2257 "Cached session key encryption key:\n"); 2258 if (ecryptfs_verbosity > 0) 2259 ecryptfs_dump_hex(session_key_encryption_key, 16); 2260 } 2261 if (unlikely(ecryptfs_verbosity > 0)) { 2262 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2263 ecryptfs_dump_hex(session_key_encryption_key, 16); 2264 } 2265 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2266 src_sg, 2); 2267 if (rc < 1 || rc > 2) { 2268 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2269 "for crypt_stat session key; expected rc = 1; " 2270 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2271 rc, key_rec->enc_key_size); 2272 rc = -ENOMEM; 2273 goto out; 2274 } 2275 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2276 dst_sg, 2); 2277 if (rc < 1 || rc > 2) { 2278 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2279 "for crypt_stat encrypted session key; " 2280 "expected rc = 1; got rc = [%d]. " 2281 "key_rec->enc_key_size = [%zd]\n", rc, 2282 key_rec->enc_key_size); 2283 rc = -ENOMEM; 2284 goto out; 2285 } 2286 mutex_lock(tfm_mutex); 2287 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key, 2288 crypt_stat->key_size); 2289 if (rc < 0) { 2290 mutex_unlock(tfm_mutex); 2291 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2292 "context; rc = [%d]\n", rc); 2293 goto out; 2294 } 2295 rc = 0; 2296 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2297 crypt_stat->key_size); 2298 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg, 2299 (*key_rec).enc_key_size); 2300 mutex_unlock(tfm_mutex); 2301 if (rc) { 2302 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2303 goto out; 2304 } 2305 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2306 if (ecryptfs_verbosity > 0) { 2307 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2308 key_rec->enc_key_size); 2309 ecryptfs_dump_hex(key_rec->enc_key, 2310 key_rec->enc_key_size); 2311 } 2312 encrypted_session_key_set: 2313 /* This format is inspired by OpenPGP; see RFC 2440 2314 * packet tag 3 */ 2315 max_packet_size = (1 /* Tag 3 identifier */ 2316 + 3 /* Max Tag 3 packet size */ 2317 + 1 /* Version */ 2318 + 1 /* Cipher code */ 2319 + 1 /* S2K specifier */ 2320 + 1 /* Hash identifier */ 2321 + ECRYPTFS_SALT_SIZE /* Salt */ 2322 + 1 /* Hash iterations */ 2323 + key_rec->enc_key_size); /* Encrypted key size */ 2324 if (max_packet_size > (*remaining_bytes)) { 2325 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2326 "there are only [%td] available\n", max_packet_size, 2327 (*remaining_bytes)); 2328 rc = -EINVAL; 2329 goto out; 2330 } 2331 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2332 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2333 * to get the number of octets in the actual Tag 3 packet */ 2334 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2335 (max_packet_size - 4), 2336 &packet_size_length); 2337 if (rc) { 2338 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2339 "generate packet length. rc = [%d]\n", rc); 2340 goto out; 2341 } 2342 (*packet_size) += packet_size_length; 2343 dest[(*packet_size)++] = 0x04; /* version 4 */ 2344 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2345 * specified with strings */ 2346 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2347 crypt_stat->key_size); 2348 if (cipher_code == 0) { 2349 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2350 "cipher [%s]\n", crypt_stat->cipher); 2351 rc = -EINVAL; 2352 goto out; 2353 } 2354 dest[(*packet_size)++] = cipher_code; 2355 dest[(*packet_size)++] = 0x03; /* S2K */ 2356 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2357 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2358 ECRYPTFS_SALT_SIZE); 2359 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2360 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2361 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2362 key_rec->enc_key_size); 2363 (*packet_size) += key_rec->enc_key_size; 2364 out: 2365 if (rc) 2366 (*packet_size) = 0; 2367 else 2368 (*remaining_bytes) -= (*packet_size); 2369 return rc; 2370 } 2371 2372 struct kmem_cache *ecryptfs_key_record_cache; 2373 2374 /** 2375 * ecryptfs_generate_key_packet_set 2376 * @dest_base: Virtual address from which to write the key record set 2377 * @crypt_stat: The cryptographic context from which the 2378 * authentication tokens will be retrieved 2379 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2380 * for the global parameters 2381 * @len: The amount written 2382 * @max: The maximum amount of data allowed to be written 2383 * 2384 * Generates a key packet set and writes it to the virtual address 2385 * passed in. 2386 * 2387 * Returns zero on success; non-zero on error. 2388 */ 2389 int 2390 ecryptfs_generate_key_packet_set(char *dest_base, 2391 struct ecryptfs_crypt_stat *crypt_stat, 2392 struct dentry *ecryptfs_dentry, size_t *len, 2393 size_t max) 2394 { 2395 struct ecryptfs_auth_tok *auth_tok; 2396 struct key *auth_tok_key = NULL; 2397 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2398 &ecryptfs_superblock_to_private( 2399 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2400 size_t written; 2401 struct ecryptfs_key_record *key_rec; 2402 struct ecryptfs_key_sig *key_sig; 2403 int rc = 0; 2404 2405 (*len) = 0; 2406 mutex_lock(&crypt_stat->keysig_list_mutex); 2407 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2408 if (!key_rec) { 2409 rc = -ENOMEM; 2410 goto out; 2411 } 2412 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2413 crypt_stat_list) { 2414 memset(key_rec, 0, sizeof(*key_rec)); 2415 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2416 &auth_tok, 2417 mount_crypt_stat, 2418 key_sig->keysig); 2419 if (rc) { 2420 printk(KERN_WARNING "Unable to retrieve auth tok with " 2421 "sig = [%s]\n", key_sig->keysig); 2422 rc = process_find_global_auth_tok_for_sig_err(rc); 2423 goto out_free; 2424 } 2425 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2426 rc = write_tag_3_packet((dest_base + (*len)), 2427 &max, auth_tok, 2428 crypt_stat, key_rec, 2429 &written); 2430 up_write(&(auth_tok_key->sem)); 2431 key_put(auth_tok_key); 2432 if (rc) { 2433 ecryptfs_printk(KERN_WARNING, "Error " 2434 "writing tag 3 packet\n"); 2435 goto out_free; 2436 } 2437 (*len) += written; 2438 /* Write auth tok signature packet */ 2439 rc = write_tag_11_packet((dest_base + (*len)), &max, 2440 key_rec->sig, 2441 ECRYPTFS_SIG_SIZE, &written); 2442 if (rc) { 2443 ecryptfs_printk(KERN_ERR, "Error writing " 2444 "auth tok signature packet\n"); 2445 goto out_free; 2446 } 2447 (*len) += written; 2448 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2449 rc = write_tag_1_packet(dest_base + (*len), &max, 2450 auth_tok_key, auth_tok, 2451 crypt_stat, key_rec, &written); 2452 if (rc) { 2453 ecryptfs_printk(KERN_WARNING, "Error " 2454 "writing tag 1 packet\n"); 2455 goto out_free; 2456 } 2457 (*len) += written; 2458 } else { 2459 up_write(&(auth_tok_key->sem)); 2460 key_put(auth_tok_key); 2461 ecryptfs_printk(KERN_WARNING, "Unsupported " 2462 "authentication token type\n"); 2463 rc = -EINVAL; 2464 goto out_free; 2465 } 2466 } 2467 if (likely(max > 0)) { 2468 dest_base[(*len)] = 0x00; 2469 } else { 2470 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2471 rc = -EIO; 2472 } 2473 out_free: 2474 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2475 out: 2476 if (rc) 2477 (*len) = 0; 2478 mutex_unlock(&crypt_stat->keysig_list_mutex); 2479 return rc; 2480 } 2481 2482 struct kmem_cache *ecryptfs_key_sig_cache; 2483 2484 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2485 { 2486 struct ecryptfs_key_sig *new_key_sig; 2487 2488 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2489 if (!new_key_sig) { 2490 printk(KERN_ERR 2491 "Error allocating from ecryptfs_key_sig_cache\n"); 2492 return -ENOMEM; 2493 } 2494 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2495 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2496 /* Caller must hold keysig_list_mutex */ 2497 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2498 2499 return 0; 2500 } 2501 2502 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2503 2504 int 2505 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2506 char *sig, u32 global_auth_tok_flags) 2507 { 2508 struct ecryptfs_global_auth_tok *new_auth_tok; 2509 int rc = 0; 2510 2511 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2512 GFP_KERNEL); 2513 if (!new_auth_tok) { 2514 rc = -ENOMEM; 2515 printk(KERN_ERR "Error allocating from " 2516 "ecryptfs_global_auth_tok_cache\n"); 2517 goto out; 2518 } 2519 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2520 new_auth_tok->flags = global_auth_tok_flags; 2521 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2522 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2523 list_add(&new_auth_tok->mount_crypt_stat_list, 2524 &mount_crypt_stat->global_auth_tok_list); 2525 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2526 out: 2527 return rc; 2528 } 2529 2530