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 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 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 ECRYPTFS_MAX_PKT_LEN_SIZE 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 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 150 rc = -EINVAL; 151 ecryptfs_printk(KERN_WARNING, 152 "Unsupported packet size: [%zd]\n", size); 153 } 154 return rc; 155 } 156 157 static int 158 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key, 159 char **packet, size_t *packet_len) 160 { 161 size_t i = 0; 162 size_t data_len; 163 size_t packet_size_len; 164 char *message; 165 int rc; 166 167 /* 168 * ***** TAG 64 Packet Format ***** 169 * | Content Type | 1 byte | 170 * | Key Identifier Size | 1 or 2 bytes | 171 * | Key Identifier | arbitrary | 172 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 173 * | Encrypted File Encryption Key | arbitrary | 174 */ 175 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX 176 + session_key->encrypted_key_size); 177 *packet = kmalloc(data_len, GFP_KERNEL); 178 message = *packet; 179 if (!message) { 180 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 181 rc = -ENOMEM; 182 goto out; 183 } 184 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE; 185 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 186 &packet_size_len); 187 if (rc) { 188 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 189 "header; cannot generate packet length\n"); 190 goto out; 191 } 192 i += packet_size_len; 193 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 194 i += ECRYPTFS_SIG_SIZE_HEX; 195 rc = ecryptfs_write_packet_length(&message[i], 196 session_key->encrypted_key_size, 197 &packet_size_len); 198 if (rc) { 199 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 200 "header; cannot generate packet length\n"); 201 goto out; 202 } 203 i += packet_size_len; 204 memcpy(&message[i], session_key->encrypted_key, 205 session_key->encrypted_key_size); 206 i += session_key->encrypted_key_size; 207 *packet_len = i; 208 out: 209 return rc; 210 } 211 212 static int 213 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code, 214 struct ecryptfs_message *msg) 215 { 216 size_t i = 0; 217 char *data; 218 size_t data_len; 219 size_t m_size; 220 size_t message_len; 221 u16 checksum = 0; 222 u16 expected_checksum = 0; 223 int rc; 224 225 /* 226 * ***** TAG 65 Packet Format ***** 227 * | Content Type | 1 byte | 228 * | Status Indicator | 1 byte | 229 * | File Encryption Key Size | 1 or 2 bytes | 230 * | File Encryption Key | arbitrary | 231 */ 232 message_len = msg->data_len; 233 data = msg->data; 234 if (message_len < 4) { 235 rc = -EIO; 236 goto out; 237 } 238 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) { 239 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n"); 240 rc = -EIO; 241 goto out; 242 } 243 if (data[i++]) { 244 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value " 245 "[%d]\n", data[i-1]); 246 rc = -EIO; 247 goto out; 248 } 249 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len); 250 if (rc) { 251 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 252 "rc = [%d]\n", rc); 253 goto out; 254 } 255 i += data_len; 256 if (message_len < (i + m_size)) { 257 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd " 258 "is shorter than expected\n"); 259 rc = -EIO; 260 goto out; 261 } 262 if (m_size < 3) { 263 ecryptfs_printk(KERN_ERR, 264 "The decrypted key is not long enough to " 265 "include a cipher code and checksum\n"); 266 rc = -EIO; 267 goto out; 268 } 269 *cipher_code = data[i++]; 270 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */ 271 session_key->decrypted_key_size = m_size - 3; 272 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) { 273 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than " 274 "the maximum key size [%d]\n", 275 session_key->decrypted_key_size, 276 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 277 rc = -EIO; 278 goto out; 279 } 280 memcpy(session_key->decrypted_key, &data[i], 281 session_key->decrypted_key_size); 282 i += session_key->decrypted_key_size; 283 expected_checksum += (unsigned char)(data[i++]) << 8; 284 expected_checksum += (unsigned char)(data[i++]); 285 for (i = 0; i < session_key->decrypted_key_size; i++) 286 checksum += session_key->decrypted_key[i]; 287 if (expected_checksum != checksum) { 288 ecryptfs_printk(KERN_ERR, "Invalid checksum for file " 289 "encryption key; expected [%x]; calculated " 290 "[%x]\n", expected_checksum, checksum); 291 rc = -EIO; 292 } 293 out: 294 return rc; 295 } 296 297 298 static int 299 write_tag_66_packet(char *signature, u8 cipher_code, 300 struct ecryptfs_crypt_stat *crypt_stat, char **packet, 301 size_t *packet_len) 302 { 303 size_t i = 0; 304 size_t j; 305 size_t data_len; 306 size_t checksum = 0; 307 size_t packet_size_len; 308 char *message; 309 int rc; 310 311 /* 312 * ***** TAG 66 Packet Format ***** 313 * | Content Type | 1 byte | 314 * | Key Identifier Size | 1 or 2 bytes | 315 * | Key Identifier | arbitrary | 316 * | File Encryption Key Size | 1 or 2 bytes | 317 * | File Encryption Key | arbitrary | 318 */ 319 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); 320 *packet = kmalloc(data_len, GFP_KERNEL); 321 message = *packet; 322 if (!message) { 323 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 324 rc = -ENOMEM; 325 goto out; 326 } 327 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; 328 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 329 &packet_size_len); 330 if (rc) { 331 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 332 "header; cannot generate packet length\n"); 333 goto out; 334 } 335 i += packet_size_len; 336 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 337 i += ECRYPTFS_SIG_SIZE_HEX; 338 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */ 339 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, 340 &packet_size_len); 341 if (rc) { 342 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 343 "header; cannot generate packet length\n"); 344 goto out; 345 } 346 i += packet_size_len; 347 message[i++] = cipher_code; 348 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); 349 i += crypt_stat->key_size; 350 for (j = 0; j < crypt_stat->key_size; j++) 351 checksum += crypt_stat->key[j]; 352 message[i++] = (checksum / 256) % 256; 353 message[i++] = (checksum % 256); 354 *packet_len = i; 355 out: 356 return rc; 357 } 358 359 static int 360 parse_tag_67_packet(struct ecryptfs_key_record *key_rec, 361 struct ecryptfs_message *msg) 362 { 363 size_t i = 0; 364 char *data; 365 size_t data_len; 366 size_t message_len; 367 int rc; 368 369 /* 370 * ***** TAG 65 Packet Format ***** 371 * | Content Type | 1 byte | 372 * | Status Indicator | 1 byte | 373 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 374 * | Encrypted File Encryption Key | arbitrary | 375 */ 376 message_len = msg->data_len; 377 data = msg->data; 378 /* verify that everything through the encrypted FEK size is present */ 379 if (message_len < 4) { 380 rc = -EIO; 381 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " 382 "message length is [%d]\n", __func__, message_len, 4); 383 goto out; 384 } 385 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { 386 rc = -EIO; 387 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", 388 __func__); 389 goto out; 390 } 391 if (data[i++]) { 392 rc = -EIO; 393 printk(KERN_ERR "%s: Status indicator has non zero " 394 "value [%d]\n", __func__, data[i-1]); 395 396 goto out; 397 } 398 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, 399 &data_len); 400 if (rc) { 401 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 402 "rc = [%d]\n", rc); 403 goto out; 404 } 405 i += data_len; 406 if (message_len < (i + key_rec->enc_key_size)) { 407 rc = -EIO; 408 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", 409 __func__, message_len, (i + key_rec->enc_key_size)); 410 goto out; 411 } 412 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 413 rc = -EIO; 414 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " 415 "the maximum key size [%d]\n", __func__, 416 key_rec->enc_key_size, 417 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 418 goto out; 419 } 420 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); 421 out: 422 return rc; 423 } 424 425 /** 426 * ecryptfs_verify_version 427 * @version: The version number to confirm 428 * 429 * Returns zero on good version; non-zero otherwise 430 */ 431 static int ecryptfs_verify_version(u16 version) 432 { 433 int rc = 0; 434 unsigned char major; 435 unsigned char minor; 436 437 major = ((version >> 8) & 0xFF); 438 minor = (version & 0xFF); 439 if (major != ECRYPTFS_VERSION_MAJOR) { 440 ecryptfs_printk(KERN_ERR, "Major version number mismatch. " 441 "Expected [%d]; got [%d]\n", 442 ECRYPTFS_VERSION_MAJOR, major); 443 rc = -EINVAL; 444 goto out; 445 } 446 if (minor != ECRYPTFS_VERSION_MINOR) { 447 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " 448 "Expected [%d]; got [%d]\n", 449 ECRYPTFS_VERSION_MINOR, minor); 450 rc = -EINVAL; 451 goto out; 452 } 453 out: 454 return rc; 455 } 456 457 /** 458 * ecryptfs_verify_auth_tok_from_key 459 * @auth_tok_key: key containing the authentication token 460 * @auth_tok: authentication token 461 * 462 * Returns zero on valid auth tok; -EINVAL otherwise 463 */ 464 static int 465 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, 466 struct ecryptfs_auth_tok **auth_tok) 467 { 468 int rc = 0; 469 470 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); 471 if (ecryptfs_verify_version((*auth_tok)->version)) { 472 printk(KERN_ERR "Data structure version mismatch. Userspace " 473 "tools must match eCryptfs kernel module with major " 474 "version [%d] and minor version [%d]\n", 475 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); 476 rc = -EINVAL; 477 goto out; 478 } 479 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD 480 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { 481 printk(KERN_ERR "Invalid auth_tok structure " 482 "returned from key query\n"); 483 rc = -EINVAL; 484 goto out; 485 } 486 out: 487 return rc; 488 } 489 490 static int 491 ecryptfs_find_global_auth_tok_for_sig( 492 struct key **auth_tok_key, 493 struct ecryptfs_auth_tok **auth_tok, 494 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) 495 { 496 struct ecryptfs_global_auth_tok *walker; 497 int rc = 0; 498 499 (*auth_tok_key) = NULL; 500 (*auth_tok) = NULL; 501 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 502 list_for_each_entry(walker, 503 &mount_crypt_stat->global_auth_tok_list, 504 mount_crypt_stat_list) { 505 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) 506 continue; 507 508 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { 509 rc = -EINVAL; 510 goto out; 511 } 512 513 rc = key_validate(walker->global_auth_tok_key); 514 if (rc) { 515 if (rc == -EKEYEXPIRED) 516 goto out; 517 goto out_invalid_auth_tok; 518 } 519 520 down_write(&(walker->global_auth_tok_key->sem)); 521 rc = ecryptfs_verify_auth_tok_from_key( 522 walker->global_auth_tok_key, auth_tok); 523 if (rc) 524 goto out_invalid_auth_tok_unlock; 525 526 (*auth_tok_key) = walker->global_auth_tok_key; 527 key_get(*auth_tok_key); 528 goto out; 529 } 530 rc = -ENOENT; 531 goto out; 532 out_invalid_auth_tok_unlock: 533 up_write(&(walker->global_auth_tok_key->sem)); 534 out_invalid_auth_tok: 535 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); 536 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; 537 key_put(walker->global_auth_tok_key); 538 walker->global_auth_tok_key = NULL; 539 out: 540 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 541 return rc; 542 } 543 544 /** 545 * ecryptfs_find_auth_tok_for_sig 546 * @auth_tok: Set to the matching auth_tok; NULL if not found 547 * @crypt_stat: inode crypt_stat crypto context 548 * @sig: Sig of auth_tok to find 549 * 550 * For now, this function simply looks at the registered auth_tok's 551 * linked off the mount_crypt_stat, so all the auth_toks that can be 552 * used must be registered at mount time. This function could 553 * potentially try a lot harder to find auth_tok's (e.g., by calling 554 * out to ecryptfsd to dynamically retrieve an auth_tok object) so 555 * that static registration of auth_tok's will no longer be necessary. 556 * 557 * Returns zero on no error; non-zero on error 558 */ 559 static int 560 ecryptfs_find_auth_tok_for_sig( 561 struct key **auth_tok_key, 562 struct ecryptfs_auth_tok **auth_tok, 563 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 564 char *sig) 565 { 566 int rc = 0; 567 568 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, 569 mount_crypt_stat, sig); 570 if (rc == -ENOENT) { 571 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the 572 * mount_crypt_stat structure, we prevent to use auth toks that 573 * are not inserted through the ecryptfs_add_global_auth_tok 574 * function. 575 */ 576 if (mount_crypt_stat->flags 577 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) 578 return -EINVAL; 579 580 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, 581 sig); 582 } 583 return rc; 584 } 585 586 /** 587 * write_tag_70_packet can gobble a lot of stack space. We stuff most 588 * of the function's parameters in a kmalloc'd struct to help reduce 589 * eCryptfs' overall stack usage. 590 */ 591 struct ecryptfs_write_tag_70_packet_silly_stack { 592 u8 cipher_code; 593 size_t max_packet_size; 594 size_t packet_size_len; 595 size_t block_aligned_filename_size; 596 size_t block_size; 597 size_t i; 598 size_t j; 599 size_t num_rand_bytes; 600 struct mutex *tfm_mutex; 601 char *block_aligned_filename; 602 struct ecryptfs_auth_tok *auth_tok; 603 struct scatterlist src_sg[2]; 604 struct scatterlist dst_sg[2]; 605 struct blkcipher_desc desc; 606 char iv[ECRYPTFS_MAX_IV_BYTES]; 607 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 608 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 609 struct hash_desc hash_desc; 610 struct scatterlist hash_sg; 611 }; 612 613 /** 614 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK 615 * @filename: NULL-terminated filename string 616 * 617 * This is the simplest mechanism for achieving filename encryption in 618 * eCryptfs. It encrypts the given filename with the mount-wide 619 * filename encryption key (FNEK) and stores it in a packet to @dest, 620 * which the callee will encode and write directly into the dentry 621 * name. 622 */ 623 int 624 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, 625 size_t *packet_size, 626 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 627 char *filename, size_t filename_size) 628 { 629 struct ecryptfs_write_tag_70_packet_silly_stack *s; 630 struct key *auth_tok_key = NULL; 631 int rc = 0; 632 633 s = kmalloc(sizeof(*s), GFP_KERNEL); 634 if (!s) { 635 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 636 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 637 rc = -ENOMEM; 638 goto out; 639 } 640 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 641 (*packet_size) = 0; 642 rc = ecryptfs_find_auth_tok_for_sig( 643 &auth_tok_key, 644 &s->auth_tok, mount_crypt_stat, 645 mount_crypt_stat->global_default_fnek_sig); 646 if (rc) { 647 printk(KERN_ERR "%s: Error attempting to find auth tok for " 648 "fnek sig [%s]; rc = [%d]\n", __func__, 649 mount_crypt_stat->global_default_fnek_sig, rc); 650 goto out; 651 } 652 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 653 &s->desc.tfm, 654 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 655 if (unlikely(rc)) { 656 printk(KERN_ERR "Internal error whilst attempting to get " 657 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 658 mount_crypt_stat->global_default_fn_cipher_name, rc); 659 goto out; 660 } 661 mutex_lock(s->tfm_mutex); 662 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm); 663 /* Plus one for the \0 separator between the random prefix 664 * and the plaintext filename */ 665 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 666 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 667 if ((s->block_aligned_filename_size % s->block_size) != 0) { 668 s->num_rand_bytes += (s->block_size 669 - (s->block_aligned_filename_size 670 % s->block_size)); 671 s->block_aligned_filename_size = (s->num_rand_bytes 672 + filename_size); 673 } 674 /* Octet 0: Tag 70 identifier 675 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 676 * and block-aligned encrypted filename size) 677 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 678 * Octet N2-N3: Cipher identifier (1 octet) 679 * Octets N3-N4: Block-aligned encrypted filename 680 * - Consists of a minimum number of random characters, a \0 681 * separator, and then the filename */ 682 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 683 + s->block_aligned_filename_size); 684 if (dest == NULL) { 685 (*packet_size) = s->max_packet_size; 686 goto out_unlock; 687 } 688 if (s->max_packet_size > (*remaining_bytes)) { 689 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 690 "[%zd] available\n", __func__, s->max_packet_size, 691 (*remaining_bytes)); 692 rc = -EINVAL; 693 goto out_unlock; 694 } 695 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 696 GFP_KERNEL); 697 if (!s->block_aligned_filename) { 698 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 699 "kzalloc [%zd] bytes\n", __func__, 700 s->block_aligned_filename_size); 701 rc = -ENOMEM; 702 goto out_unlock; 703 } 704 s->i = 0; 705 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 706 rc = ecryptfs_write_packet_length(&dest[s->i], 707 (ECRYPTFS_SIG_SIZE 708 + 1 /* Cipher code */ 709 + s->block_aligned_filename_size), 710 &s->packet_size_len); 711 if (rc) { 712 printk(KERN_ERR "%s: Error generating tag 70 packet " 713 "header; cannot generate packet length; rc = [%d]\n", 714 __func__, rc); 715 goto out_free_unlock; 716 } 717 s->i += s->packet_size_len; 718 ecryptfs_from_hex(&dest[s->i], 719 mount_crypt_stat->global_default_fnek_sig, 720 ECRYPTFS_SIG_SIZE); 721 s->i += ECRYPTFS_SIG_SIZE; 722 s->cipher_code = ecryptfs_code_for_cipher_string( 723 mount_crypt_stat->global_default_fn_cipher_name, 724 mount_crypt_stat->global_default_fn_cipher_key_bytes); 725 if (s->cipher_code == 0) { 726 printk(KERN_WARNING "%s: Unable to generate code for " 727 "cipher [%s] with key bytes [%zd]\n", __func__, 728 mount_crypt_stat->global_default_fn_cipher_name, 729 mount_crypt_stat->global_default_fn_cipher_key_bytes); 730 rc = -EINVAL; 731 goto out_free_unlock; 732 } 733 dest[s->i++] = s->cipher_code; 734 /* TODO: Support other key modules than passphrase for 735 * filename encryption */ 736 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 737 rc = -EOPNOTSUPP; 738 printk(KERN_INFO "%s: Filename encryption only supports " 739 "password tokens\n", __func__); 740 goto out_free_unlock; 741 } 742 sg_init_one( 743 &s->hash_sg, 744 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 745 s->auth_tok->token.password.session_key_encryption_key_bytes); 746 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 747 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0, 748 CRYPTO_ALG_ASYNC); 749 if (IS_ERR(s->hash_desc.tfm)) { 750 rc = PTR_ERR(s->hash_desc.tfm); 751 printk(KERN_ERR "%s: Error attempting to " 752 "allocate hash crypto context; rc = [%d]\n", 753 __func__, rc); 754 goto out_free_unlock; 755 } 756 rc = crypto_hash_init(&s->hash_desc); 757 if (rc) { 758 printk(KERN_ERR 759 "%s: Error initializing crypto hash; rc = [%d]\n", 760 __func__, rc); 761 goto out_release_free_unlock; 762 } 763 rc = crypto_hash_update( 764 &s->hash_desc, &s->hash_sg, 765 s->auth_tok->token.password.session_key_encryption_key_bytes); 766 if (rc) { 767 printk(KERN_ERR 768 "%s: Error updating crypto hash; rc = [%d]\n", 769 __func__, rc); 770 goto out_release_free_unlock; 771 } 772 rc = crypto_hash_final(&s->hash_desc, s->hash); 773 if (rc) { 774 printk(KERN_ERR 775 "%s: Error finalizing crypto hash; rc = [%d]\n", 776 __func__, rc); 777 goto out_release_free_unlock; 778 } 779 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 780 s->block_aligned_filename[s->j] = 781 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 782 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 783 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 784 sg_init_one(&s->hash_sg, (u8 *)s->hash, 785 ECRYPTFS_TAG_70_DIGEST_SIZE); 786 rc = crypto_hash_init(&s->hash_desc); 787 if (rc) { 788 printk(KERN_ERR 789 "%s: Error initializing crypto hash; " 790 "rc = [%d]\n", __func__, rc); 791 goto out_release_free_unlock; 792 } 793 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg, 794 ECRYPTFS_TAG_70_DIGEST_SIZE); 795 if (rc) { 796 printk(KERN_ERR 797 "%s: Error updating crypto hash; " 798 "rc = [%d]\n", __func__, rc); 799 goto out_release_free_unlock; 800 } 801 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash); 802 if (rc) { 803 printk(KERN_ERR 804 "%s: Error finalizing crypto hash; " 805 "rc = [%d]\n", __func__, rc); 806 goto out_release_free_unlock; 807 } 808 memcpy(s->hash, s->tmp_hash, 809 ECRYPTFS_TAG_70_DIGEST_SIZE); 810 } 811 if (s->block_aligned_filename[s->j] == '\0') 812 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 813 } 814 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 815 filename_size); 816 rc = virt_to_scatterlist(s->block_aligned_filename, 817 s->block_aligned_filename_size, s->src_sg, 2); 818 if (rc < 1) { 819 printk(KERN_ERR "%s: Internal error whilst attempting to " 820 "convert filename memory to scatterlist; rc = [%d]. " 821 "block_aligned_filename_size = [%zd]\n", __func__, rc, 822 s->block_aligned_filename_size); 823 goto out_release_free_unlock; 824 } 825 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 826 s->dst_sg, 2); 827 if (rc < 1) { 828 printk(KERN_ERR "%s: Internal error whilst attempting to " 829 "convert encrypted filename memory to scatterlist; " 830 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 831 __func__, rc, s->block_aligned_filename_size); 832 goto out_release_free_unlock; 833 } 834 /* The characters in the first block effectively do the job 835 * of the IV here, so we just use 0's for the IV. Note the 836 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 837 * >= ECRYPTFS_MAX_IV_BYTES. */ 838 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 839 s->desc.info = s->iv; 840 rc = crypto_blkcipher_setkey( 841 s->desc.tfm, 842 s->auth_tok->token.password.session_key_encryption_key, 843 mount_crypt_stat->global_default_fn_cipher_key_bytes); 844 if (rc < 0) { 845 printk(KERN_ERR "%s: Error setting key for crypto context; " 846 "rc = [%d]. s->auth_tok->token.password.session_key_" 847 "encryption_key = [0x%p]; mount_crypt_stat->" 848 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 849 rc, 850 s->auth_tok->token.password.session_key_encryption_key, 851 mount_crypt_stat->global_default_fn_cipher_key_bytes); 852 goto out_release_free_unlock; 853 } 854 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg, 855 s->block_aligned_filename_size); 856 if (rc) { 857 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 858 "rc = [%d]\n", __func__, rc); 859 goto out_release_free_unlock; 860 } 861 s->i += s->block_aligned_filename_size; 862 (*packet_size) = s->i; 863 (*remaining_bytes) -= (*packet_size); 864 out_release_free_unlock: 865 crypto_free_hash(s->hash_desc.tfm); 866 out_free_unlock: 867 kzfree(s->block_aligned_filename); 868 out_unlock: 869 mutex_unlock(s->tfm_mutex); 870 out: 871 if (auth_tok_key) { 872 up_write(&(auth_tok_key->sem)); 873 key_put(auth_tok_key); 874 } 875 kfree(s); 876 return rc; 877 } 878 879 struct ecryptfs_parse_tag_70_packet_silly_stack { 880 u8 cipher_code; 881 size_t max_packet_size; 882 size_t packet_size_len; 883 size_t parsed_tag_70_packet_size; 884 size_t block_aligned_filename_size; 885 size_t block_size; 886 size_t i; 887 struct mutex *tfm_mutex; 888 char *decrypted_filename; 889 struct ecryptfs_auth_tok *auth_tok; 890 struct scatterlist src_sg[2]; 891 struct scatterlist dst_sg[2]; 892 struct blkcipher_desc desc; 893 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 894 char iv[ECRYPTFS_MAX_IV_BYTES]; 895 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE]; 896 }; 897 898 /** 899 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 900 * @filename: This function kmalloc's the memory for the filename 901 * @filename_size: This function sets this to the amount of memory 902 * kmalloc'd for the filename 903 * @packet_size: This function sets this to the the number of octets 904 * in the packet parsed 905 * @mount_crypt_stat: The mount-wide cryptographic context 906 * @data: The memory location containing the start of the tag 70 907 * packet 908 * @max_packet_size: The maximum legal size of the packet to be parsed 909 * from @data 910 * 911 * Returns zero on success; non-zero otherwise 912 */ 913 int 914 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 915 size_t *packet_size, 916 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 917 char *data, size_t max_packet_size) 918 { 919 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 920 struct key *auth_tok_key = NULL; 921 int rc = 0; 922 923 (*packet_size) = 0; 924 (*filename_size) = 0; 925 (*filename) = NULL; 926 s = kmalloc(sizeof(*s), GFP_KERNEL); 927 if (!s) { 928 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 929 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 930 rc = -ENOMEM; 931 goto out; 932 } 933 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 934 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 935 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 936 "at least [%d]\n", __func__, max_packet_size, 937 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 938 rc = -EINVAL; 939 goto out; 940 } 941 /* Octet 0: Tag 70 identifier 942 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 943 * and block-aligned encrypted filename size) 944 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 945 * Octet N2-N3: Cipher identifier (1 octet) 946 * Octets N3-N4: Block-aligned encrypted filename 947 * - Consists of a minimum number of random numbers, a \0 948 * separator, and then the filename */ 949 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 950 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 951 "tag [0x%.2x]\n", __func__, 952 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 953 rc = -EINVAL; 954 goto out; 955 } 956 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 957 &s->parsed_tag_70_packet_size, 958 &s->packet_size_len); 959 if (rc) { 960 printk(KERN_WARNING "%s: Error parsing packet length; " 961 "rc = [%d]\n", __func__, rc); 962 goto out; 963 } 964 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 965 - ECRYPTFS_SIG_SIZE - 1); 966 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 967 > max_packet_size) { 968 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 969 "size is [%zd]\n", __func__, max_packet_size, 970 (1 + s->packet_size_len + 1 971 + s->block_aligned_filename_size)); 972 rc = -EINVAL; 973 goto out; 974 } 975 (*packet_size) += s->packet_size_len; 976 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 977 ECRYPTFS_SIG_SIZE); 978 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 979 (*packet_size) += ECRYPTFS_SIG_SIZE; 980 s->cipher_code = data[(*packet_size)++]; 981 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 982 if (rc) { 983 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 984 __func__, s->cipher_code); 985 goto out; 986 } 987 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 988 &s->auth_tok, mount_crypt_stat, 989 s->fnek_sig_hex); 990 if (rc) { 991 printk(KERN_ERR "%s: Error attempting to find auth tok for " 992 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 993 rc); 994 goto out; 995 } 996 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm, 997 &s->tfm_mutex, 998 s->cipher_string); 999 if (unlikely(rc)) { 1000 printk(KERN_ERR "Internal error whilst attempting to get " 1001 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1002 s->cipher_string, rc); 1003 goto out; 1004 } 1005 mutex_lock(s->tfm_mutex); 1006 rc = virt_to_scatterlist(&data[(*packet_size)], 1007 s->block_aligned_filename_size, s->src_sg, 2); 1008 if (rc < 1) { 1009 printk(KERN_ERR "%s: Internal error whilst attempting to " 1010 "convert encrypted filename memory to scatterlist; " 1011 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1012 __func__, rc, s->block_aligned_filename_size); 1013 goto out_unlock; 1014 } 1015 (*packet_size) += s->block_aligned_filename_size; 1016 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 1017 GFP_KERNEL); 1018 if (!s->decrypted_filename) { 1019 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1020 "kmalloc [%zd] bytes\n", __func__, 1021 s->block_aligned_filename_size); 1022 rc = -ENOMEM; 1023 goto out_unlock; 1024 } 1025 rc = virt_to_scatterlist(s->decrypted_filename, 1026 s->block_aligned_filename_size, s->dst_sg, 2); 1027 if (rc < 1) { 1028 printk(KERN_ERR "%s: Internal error whilst attempting to " 1029 "convert decrypted filename memory to scatterlist; " 1030 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1031 __func__, rc, s->block_aligned_filename_size); 1032 goto out_free_unlock; 1033 } 1034 /* The characters in the first block effectively do the job of 1035 * the IV here, so we just use 0's for the IV. Note the 1036 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1037 * >= ECRYPTFS_MAX_IV_BYTES. */ 1038 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 1039 s->desc.info = s->iv; 1040 /* TODO: Support other key modules than passphrase for 1041 * filename encryption */ 1042 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1043 rc = -EOPNOTSUPP; 1044 printk(KERN_INFO "%s: Filename encryption only supports " 1045 "password tokens\n", __func__); 1046 goto out_free_unlock; 1047 } 1048 rc = crypto_blkcipher_setkey( 1049 s->desc.tfm, 1050 s->auth_tok->token.password.session_key_encryption_key, 1051 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1052 if (rc < 0) { 1053 printk(KERN_ERR "%s: Error setting key for crypto context; " 1054 "rc = [%d]. s->auth_tok->token.password.session_key_" 1055 "encryption_key = [0x%p]; mount_crypt_stat->" 1056 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1057 rc, 1058 s->auth_tok->token.password.session_key_encryption_key, 1059 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1060 goto out_free_unlock; 1061 } 1062 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg, 1063 s->block_aligned_filename_size); 1064 if (rc) { 1065 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1066 "rc = [%d]\n", __func__, rc); 1067 goto out_free_unlock; 1068 } 1069 s->i = 0; 1070 while (s->decrypted_filename[s->i] != '\0' 1071 && s->i < s->block_aligned_filename_size) 1072 s->i++; 1073 if (s->i == s->block_aligned_filename_size) { 1074 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1075 "find valid separator between random characters and " 1076 "the filename\n", __func__); 1077 rc = -EINVAL; 1078 goto out_free_unlock; 1079 } 1080 s->i++; 1081 (*filename_size) = (s->block_aligned_filename_size - s->i); 1082 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1083 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1084 "invalid\n", __func__, (*filename_size)); 1085 rc = -EINVAL; 1086 goto out_free_unlock; 1087 } 1088 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1089 if (!(*filename)) { 1090 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1091 "kmalloc [%zd] bytes\n", __func__, 1092 ((*filename_size) + 1)); 1093 rc = -ENOMEM; 1094 goto out_free_unlock; 1095 } 1096 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1097 (*filename)[(*filename_size)] = '\0'; 1098 out_free_unlock: 1099 kfree(s->decrypted_filename); 1100 out_unlock: 1101 mutex_unlock(s->tfm_mutex); 1102 out: 1103 if (rc) { 1104 (*packet_size) = 0; 1105 (*filename_size) = 0; 1106 (*filename) = NULL; 1107 } 1108 if (auth_tok_key) { 1109 up_write(&(auth_tok_key->sem)); 1110 key_put(auth_tok_key); 1111 } 1112 kfree(s); 1113 return rc; 1114 } 1115 1116 static int 1117 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1118 { 1119 int rc = 0; 1120 1121 (*sig) = NULL; 1122 switch (auth_tok->token_type) { 1123 case ECRYPTFS_PASSWORD: 1124 (*sig) = auth_tok->token.password.signature; 1125 break; 1126 case ECRYPTFS_PRIVATE_KEY: 1127 (*sig) = auth_tok->token.private_key.signature; 1128 break; 1129 default: 1130 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1131 auth_tok->token_type); 1132 rc = -EINVAL; 1133 } 1134 return rc; 1135 } 1136 1137 /** 1138 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1139 * @auth_tok: The key authentication token used to decrypt the session key 1140 * @crypt_stat: The cryptographic context 1141 * 1142 * Returns zero on success; non-zero error otherwise. 1143 */ 1144 static int 1145 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1146 struct ecryptfs_crypt_stat *crypt_stat) 1147 { 1148 u8 cipher_code = 0; 1149 struct ecryptfs_msg_ctx *msg_ctx; 1150 struct ecryptfs_message *msg = NULL; 1151 char *auth_tok_sig; 1152 char *payload; 1153 size_t payload_len; 1154 int rc; 1155 1156 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1157 if (rc) { 1158 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1159 auth_tok->token_type); 1160 goto out; 1161 } 1162 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1163 &payload, &payload_len); 1164 if (rc) { 1165 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1166 goto out; 1167 } 1168 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1169 if (rc) { 1170 ecryptfs_printk(KERN_ERR, "Error sending message to " 1171 "ecryptfsd\n"); 1172 goto out; 1173 } 1174 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1175 if (rc) { 1176 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1177 "from the user space daemon\n"); 1178 rc = -EIO; 1179 goto out; 1180 } 1181 rc = parse_tag_65_packet(&(auth_tok->session_key), 1182 &cipher_code, msg); 1183 if (rc) { 1184 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1185 rc); 1186 goto out; 1187 } 1188 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1189 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1190 auth_tok->session_key.decrypted_key_size); 1191 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1192 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1193 if (rc) { 1194 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1195 cipher_code) 1196 goto out; 1197 } 1198 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1199 if (ecryptfs_verbosity > 0) { 1200 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1201 ecryptfs_dump_hex(crypt_stat->key, 1202 crypt_stat->key_size); 1203 } 1204 out: 1205 if (msg) 1206 kfree(msg); 1207 return rc; 1208 } 1209 1210 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1211 { 1212 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1213 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1214 1215 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1216 auth_tok_list_head, list) { 1217 list_del(&auth_tok_list_item->list); 1218 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1219 auth_tok_list_item); 1220 } 1221 } 1222 1223 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1224 1225 /** 1226 * parse_tag_1_packet 1227 * @crypt_stat: The cryptographic context to modify based on packet contents 1228 * @data: The raw bytes of the packet. 1229 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1230 * a new authentication token will be placed at the 1231 * end of this list for this packet. 1232 * @new_auth_tok: Pointer to a pointer to memory that this function 1233 * allocates; sets the memory address of the pointer to 1234 * NULL on error. This object is added to the 1235 * auth_tok_list. 1236 * @packet_size: This function writes the size of the parsed packet 1237 * into this memory location; zero on error. 1238 * @max_packet_size: The maximum allowable packet size 1239 * 1240 * Returns zero on success; non-zero on error. 1241 */ 1242 static int 1243 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1244 unsigned char *data, struct list_head *auth_tok_list, 1245 struct ecryptfs_auth_tok **new_auth_tok, 1246 size_t *packet_size, size_t max_packet_size) 1247 { 1248 size_t body_size; 1249 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1250 size_t length_size; 1251 int rc = 0; 1252 1253 (*packet_size) = 0; 1254 (*new_auth_tok) = NULL; 1255 /** 1256 * This format is inspired by OpenPGP; see RFC 2440 1257 * packet tag 1 1258 * 1259 * Tag 1 identifier (1 byte) 1260 * Max Tag 1 packet size (max 3 bytes) 1261 * Version (1 byte) 1262 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1263 * Cipher identifier (1 byte) 1264 * Encrypted key size (arbitrary) 1265 * 1266 * 12 bytes minimum packet size 1267 */ 1268 if (unlikely(max_packet_size < 12)) { 1269 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1270 rc = -EINVAL; 1271 goto out; 1272 } 1273 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1274 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1275 ECRYPTFS_TAG_1_PACKET_TYPE); 1276 rc = -EINVAL; 1277 goto out; 1278 } 1279 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1280 * at end of function upon failure */ 1281 auth_tok_list_item = 1282 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1283 GFP_KERNEL); 1284 if (!auth_tok_list_item) { 1285 printk(KERN_ERR "Unable to allocate memory\n"); 1286 rc = -ENOMEM; 1287 goto out; 1288 } 1289 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1290 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1291 &length_size); 1292 if (rc) { 1293 printk(KERN_WARNING "Error parsing packet length; " 1294 "rc = [%d]\n", rc); 1295 goto out_free; 1296 } 1297 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1298 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1299 rc = -EINVAL; 1300 goto out_free; 1301 } 1302 (*packet_size) += length_size; 1303 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1304 printk(KERN_WARNING "Packet size exceeds max\n"); 1305 rc = -EINVAL; 1306 goto out_free; 1307 } 1308 if (unlikely(data[(*packet_size)++] != 0x03)) { 1309 printk(KERN_WARNING "Unknown version number [%d]\n", 1310 data[(*packet_size) - 1]); 1311 rc = -EINVAL; 1312 goto out_free; 1313 } 1314 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1315 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1316 *packet_size += ECRYPTFS_SIG_SIZE; 1317 /* This byte is skipped because the kernel does not need to 1318 * know which public key encryption algorithm was used */ 1319 (*packet_size)++; 1320 (*new_auth_tok)->session_key.encrypted_key_size = 1321 body_size - (ECRYPTFS_SIG_SIZE + 2); 1322 if ((*new_auth_tok)->session_key.encrypted_key_size 1323 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1324 printk(KERN_WARNING "Tag 1 packet contains key larger " 1325 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); 1326 rc = -EINVAL; 1327 goto out; 1328 } 1329 memcpy((*new_auth_tok)->session_key.encrypted_key, 1330 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1331 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1332 (*new_auth_tok)->session_key.flags &= 1333 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1334 (*new_auth_tok)->session_key.flags |= 1335 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1336 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1337 (*new_auth_tok)->flags = 0; 1338 (*new_auth_tok)->session_key.flags &= 1339 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1340 (*new_auth_tok)->session_key.flags &= 1341 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1342 list_add(&auth_tok_list_item->list, auth_tok_list); 1343 goto out; 1344 out_free: 1345 (*new_auth_tok) = NULL; 1346 memset(auth_tok_list_item, 0, 1347 sizeof(struct ecryptfs_auth_tok_list_item)); 1348 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1349 auth_tok_list_item); 1350 out: 1351 if (rc) 1352 (*packet_size) = 0; 1353 return rc; 1354 } 1355 1356 /** 1357 * parse_tag_3_packet 1358 * @crypt_stat: The cryptographic context to modify based on packet 1359 * contents. 1360 * @data: The raw bytes of the packet. 1361 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1362 * a new authentication token will be placed at the end 1363 * of this list for this packet. 1364 * @new_auth_tok: Pointer to a pointer to memory that this function 1365 * allocates; sets the memory address of the pointer to 1366 * NULL on error. This object is added to the 1367 * auth_tok_list. 1368 * @packet_size: This function writes the size of the parsed packet 1369 * into this memory location; zero on error. 1370 * @max_packet_size: maximum number of bytes to parse 1371 * 1372 * Returns zero on success; non-zero on error. 1373 */ 1374 static int 1375 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1376 unsigned char *data, struct list_head *auth_tok_list, 1377 struct ecryptfs_auth_tok **new_auth_tok, 1378 size_t *packet_size, size_t max_packet_size) 1379 { 1380 size_t body_size; 1381 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1382 size_t length_size; 1383 int rc = 0; 1384 1385 (*packet_size) = 0; 1386 (*new_auth_tok) = NULL; 1387 /** 1388 *This format is inspired by OpenPGP; see RFC 2440 1389 * packet tag 3 1390 * 1391 * Tag 3 identifier (1 byte) 1392 * Max Tag 3 packet size (max 3 bytes) 1393 * Version (1 byte) 1394 * Cipher code (1 byte) 1395 * S2K specifier (1 byte) 1396 * Hash identifier (1 byte) 1397 * Salt (ECRYPTFS_SALT_SIZE) 1398 * Hash iterations (1 byte) 1399 * Encrypted key (arbitrary) 1400 * 1401 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1402 */ 1403 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1404 printk(KERN_ERR "Max packet size too large\n"); 1405 rc = -EINVAL; 1406 goto out; 1407 } 1408 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1409 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1410 ECRYPTFS_TAG_3_PACKET_TYPE); 1411 rc = -EINVAL; 1412 goto out; 1413 } 1414 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1415 * at end of function upon failure */ 1416 auth_tok_list_item = 1417 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1418 if (!auth_tok_list_item) { 1419 printk(KERN_ERR "Unable to allocate memory\n"); 1420 rc = -ENOMEM; 1421 goto out; 1422 } 1423 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1424 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1425 &length_size); 1426 if (rc) { 1427 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1428 rc); 1429 goto out_free; 1430 } 1431 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1432 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1433 rc = -EINVAL; 1434 goto out_free; 1435 } 1436 (*packet_size) += length_size; 1437 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1438 printk(KERN_ERR "Packet size exceeds max\n"); 1439 rc = -EINVAL; 1440 goto out_free; 1441 } 1442 (*new_auth_tok)->session_key.encrypted_key_size = 1443 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1444 if ((*new_auth_tok)->session_key.encrypted_key_size 1445 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1446 printk(KERN_WARNING "Tag 3 packet contains key larger " 1447 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1448 rc = -EINVAL; 1449 goto out_free; 1450 } 1451 if (unlikely(data[(*packet_size)++] != 0x04)) { 1452 printk(KERN_WARNING "Unknown version number [%d]\n", 1453 data[(*packet_size) - 1]); 1454 rc = -EINVAL; 1455 goto out_free; 1456 } 1457 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1458 (u16)data[(*packet_size)]); 1459 if (rc) 1460 goto out_free; 1461 /* A little extra work to differentiate among the AES key 1462 * sizes; see RFC2440 */ 1463 switch(data[(*packet_size)++]) { 1464 case RFC2440_CIPHER_AES_192: 1465 crypt_stat->key_size = 24; 1466 break; 1467 default: 1468 crypt_stat->key_size = 1469 (*new_auth_tok)->session_key.encrypted_key_size; 1470 } 1471 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1472 if (rc) 1473 goto out_free; 1474 if (unlikely(data[(*packet_size)++] != 0x03)) { 1475 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1476 rc = -ENOSYS; 1477 goto out_free; 1478 } 1479 /* TODO: finish the hash mapping */ 1480 switch (data[(*packet_size)++]) { 1481 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1482 /* Choose MD5 */ 1483 memcpy((*new_auth_tok)->token.password.salt, 1484 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1485 (*packet_size) += ECRYPTFS_SALT_SIZE; 1486 /* This conversion was taken straight from RFC2440 */ 1487 (*new_auth_tok)->token.password.hash_iterations = 1488 ((u32) 16 + (data[(*packet_size)] & 15)) 1489 << ((data[(*packet_size)] >> 4) + 6); 1490 (*packet_size)++; 1491 /* Friendly reminder: 1492 * (*new_auth_tok)->session_key.encrypted_key_size = 1493 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1494 memcpy((*new_auth_tok)->session_key.encrypted_key, 1495 &data[(*packet_size)], 1496 (*new_auth_tok)->session_key.encrypted_key_size); 1497 (*packet_size) += 1498 (*new_auth_tok)->session_key.encrypted_key_size; 1499 (*new_auth_tok)->session_key.flags &= 1500 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1501 (*new_auth_tok)->session_key.flags |= 1502 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1503 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1504 break; 1505 default: 1506 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1507 "[%d]\n", data[(*packet_size) - 1]); 1508 rc = -ENOSYS; 1509 goto out_free; 1510 } 1511 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1512 /* TODO: Parametarize; we might actually want userspace to 1513 * decrypt the session key. */ 1514 (*new_auth_tok)->session_key.flags &= 1515 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1516 (*new_auth_tok)->session_key.flags &= 1517 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1518 list_add(&auth_tok_list_item->list, auth_tok_list); 1519 goto out; 1520 out_free: 1521 (*new_auth_tok) = NULL; 1522 memset(auth_tok_list_item, 0, 1523 sizeof(struct ecryptfs_auth_tok_list_item)); 1524 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1525 auth_tok_list_item); 1526 out: 1527 if (rc) 1528 (*packet_size) = 0; 1529 return rc; 1530 } 1531 1532 /** 1533 * parse_tag_11_packet 1534 * @data: The raw bytes of the packet 1535 * @contents: This function writes the data contents of the literal 1536 * packet into this memory location 1537 * @max_contents_bytes: The maximum number of bytes that this function 1538 * is allowed to write into contents 1539 * @tag_11_contents_size: This function writes the size of the parsed 1540 * contents into this memory location; zero on 1541 * error 1542 * @packet_size: This function writes the size of the parsed packet 1543 * into this memory location; zero on error 1544 * @max_packet_size: maximum number of bytes to parse 1545 * 1546 * Returns zero on success; non-zero on error. 1547 */ 1548 static int 1549 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1550 size_t max_contents_bytes, size_t *tag_11_contents_size, 1551 size_t *packet_size, size_t max_packet_size) 1552 { 1553 size_t body_size; 1554 size_t length_size; 1555 int rc = 0; 1556 1557 (*packet_size) = 0; 1558 (*tag_11_contents_size) = 0; 1559 /* This format is inspired by OpenPGP; see RFC 2440 1560 * packet tag 11 1561 * 1562 * Tag 11 identifier (1 byte) 1563 * Max Tag 11 packet size (max 3 bytes) 1564 * Binary format specifier (1 byte) 1565 * Filename length (1 byte) 1566 * Filename ("_CONSOLE") (8 bytes) 1567 * Modification date (4 bytes) 1568 * Literal data (arbitrary) 1569 * 1570 * We need at least 16 bytes of data for the packet to even be 1571 * valid. 1572 */ 1573 if (max_packet_size < 16) { 1574 printk(KERN_ERR "Maximum packet size too small\n"); 1575 rc = -EINVAL; 1576 goto out; 1577 } 1578 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1579 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1580 rc = -EINVAL; 1581 goto out; 1582 } 1583 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1584 &length_size); 1585 if (rc) { 1586 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1587 goto out; 1588 } 1589 if (body_size < 14) { 1590 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1591 rc = -EINVAL; 1592 goto out; 1593 } 1594 (*packet_size) += length_size; 1595 (*tag_11_contents_size) = (body_size - 14); 1596 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1597 printk(KERN_ERR "Packet size exceeds max\n"); 1598 rc = -EINVAL; 1599 goto out; 1600 } 1601 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1602 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1603 "expected size\n"); 1604 rc = -EINVAL; 1605 goto out; 1606 } 1607 if (data[(*packet_size)++] != 0x62) { 1608 printk(KERN_WARNING "Unrecognizable packet\n"); 1609 rc = -EINVAL; 1610 goto out; 1611 } 1612 if (data[(*packet_size)++] != 0x08) { 1613 printk(KERN_WARNING "Unrecognizable packet\n"); 1614 rc = -EINVAL; 1615 goto out; 1616 } 1617 (*packet_size) += 12; /* Ignore filename and modification date */ 1618 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1619 (*packet_size) += (*tag_11_contents_size); 1620 out: 1621 if (rc) { 1622 (*packet_size) = 0; 1623 (*tag_11_contents_size) = 0; 1624 } 1625 return rc; 1626 } 1627 1628 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1629 struct ecryptfs_auth_tok **auth_tok, 1630 char *sig) 1631 { 1632 int rc = 0; 1633 1634 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1635 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1636 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1637 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1638 printk(KERN_ERR "Could not find key with description: [%s]\n", 1639 sig); 1640 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1641 (*auth_tok_key) = NULL; 1642 goto out; 1643 } 1644 } 1645 down_write(&(*auth_tok_key)->sem); 1646 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1647 if (rc) { 1648 up_write(&(*auth_tok_key)->sem); 1649 key_put(*auth_tok_key); 1650 (*auth_tok_key) = NULL; 1651 goto out; 1652 } 1653 out: 1654 return rc; 1655 } 1656 1657 /** 1658 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1659 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1660 * @crypt_stat: The cryptographic context 1661 * 1662 * Returns zero on success; non-zero error otherwise 1663 */ 1664 static int 1665 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1666 struct ecryptfs_crypt_stat *crypt_stat) 1667 { 1668 struct scatterlist dst_sg[2]; 1669 struct scatterlist src_sg[2]; 1670 struct mutex *tfm_mutex; 1671 struct blkcipher_desc desc = { 1672 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 1673 }; 1674 int rc = 0; 1675 1676 if (unlikely(ecryptfs_verbosity > 0)) { 1677 ecryptfs_printk( 1678 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1679 auth_tok->token.password.session_key_encryption_key_bytes); 1680 ecryptfs_dump_hex( 1681 auth_tok->token.password.session_key_encryption_key, 1682 auth_tok->token.password.session_key_encryption_key_bytes); 1683 } 1684 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 1685 crypt_stat->cipher); 1686 if (unlikely(rc)) { 1687 printk(KERN_ERR "Internal error whilst attempting to get " 1688 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1689 crypt_stat->cipher, rc); 1690 goto out; 1691 } 1692 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1693 auth_tok->session_key.encrypted_key_size, 1694 src_sg, 2); 1695 if (rc < 1 || rc > 2) { 1696 printk(KERN_ERR "Internal error whilst attempting to convert " 1697 "auth_tok->session_key.encrypted_key to scatterlist; " 1698 "expected rc = 1; got rc = [%d]. " 1699 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1700 auth_tok->session_key.encrypted_key_size); 1701 goto out; 1702 } 1703 auth_tok->session_key.decrypted_key_size = 1704 auth_tok->session_key.encrypted_key_size; 1705 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1706 auth_tok->session_key.decrypted_key_size, 1707 dst_sg, 2); 1708 if (rc < 1 || rc > 2) { 1709 printk(KERN_ERR "Internal error whilst attempting to convert " 1710 "auth_tok->session_key.decrypted_key to scatterlist; " 1711 "expected rc = 1; got rc = [%d]\n", rc); 1712 goto out; 1713 } 1714 mutex_lock(tfm_mutex); 1715 rc = crypto_blkcipher_setkey( 1716 desc.tfm, auth_tok->token.password.session_key_encryption_key, 1717 crypt_stat->key_size); 1718 if (unlikely(rc < 0)) { 1719 mutex_unlock(tfm_mutex); 1720 printk(KERN_ERR "Error setting key for crypto context\n"); 1721 rc = -EINVAL; 1722 goto out; 1723 } 1724 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg, 1725 auth_tok->session_key.encrypted_key_size); 1726 mutex_unlock(tfm_mutex); 1727 if (unlikely(rc)) { 1728 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1729 goto out; 1730 } 1731 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1732 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1733 auth_tok->session_key.decrypted_key_size); 1734 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1735 if (unlikely(ecryptfs_verbosity > 0)) { 1736 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1737 crypt_stat->key_size); 1738 ecryptfs_dump_hex(crypt_stat->key, 1739 crypt_stat->key_size); 1740 } 1741 out: 1742 return rc; 1743 } 1744 1745 /** 1746 * ecryptfs_parse_packet_set 1747 * @crypt_stat: The cryptographic context 1748 * @src: Virtual address of region of memory containing the packets 1749 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1750 * 1751 * Get crypt_stat to have the file's session key if the requisite key 1752 * is available to decrypt the session key. 1753 * 1754 * Returns Zero if a valid authentication token was retrieved and 1755 * processed; negative value for file not encrypted or for error 1756 * conditions. 1757 */ 1758 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1759 unsigned char *src, 1760 struct dentry *ecryptfs_dentry) 1761 { 1762 size_t i = 0; 1763 size_t found_auth_tok; 1764 size_t next_packet_is_auth_tok_packet; 1765 struct list_head auth_tok_list; 1766 struct ecryptfs_auth_tok *matching_auth_tok; 1767 struct ecryptfs_auth_tok *candidate_auth_tok; 1768 char *candidate_auth_tok_sig; 1769 size_t packet_size; 1770 struct ecryptfs_auth_tok *new_auth_tok; 1771 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1772 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1773 size_t tag_11_contents_size; 1774 size_t tag_11_packet_size; 1775 struct key *auth_tok_key = NULL; 1776 int rc = 0; 1777 1778 INIT_LIST_HEAD(&auth_tok_list); 1779 /* Parse the header to find as many packets as we can; these will be 1780 * added the our &auth_tok_list */ 1781 next_packet_is_auth_tok_packet = 1; 1782 while (next_packet_is_auth_tok_packet) { 1783 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i); 1784 1785 switch (src[i]) { 1786 case ECRYPTFS_TAG_3_PACKET_TYPE: 1787 rc = parse_tag_3_packet(crypt_stat, 1788 (unsigned char *)&src[i], 1789 &auth_tok_list, &new_auth_tok, 1790 &packet_size, max_packet_size); 1791 if (rc) { 1792 ecryptfs_printk(KERN_ERR, "Error parsing " 1793 "tag 3 packet\n"); 1794 rc = -EIO; 1795 goto out_wipe_list; 1796 } 1797 i += packet_size; 1798 rc = parse_tag_11_packet((unsigned char *)&src[i], 1799 sig_tmp_space, 1800 ECRYPTFS_SIG_SIZE, 1801 &tag_11_contents_size, 1802 &tag_11_packet_size, 1803 max_packet_size); 1804 if (rc) { 1805 ecryptfs_printk(KERN_ERR, "No valid " 1806 "(ecryptfs-specific) literal " 1807 "packet containing " 1808 "authentication token " 1809 "signature found after " 1810 "tag 3 packet\n"); 1811 rc = -EIO; 1812 goto out_wipe_list; 1813 } 1814 i += tag_11_packet_size; 1815 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1816 ecryptfs_printk(KERN_ERR, "Expected " 1817 "signature of size [%d]; " 1818 "read size [%zd]\n", 1819 ECRYPTFS_SIG_SIZE, 1820 tag_11_contents_size); 1821 rc = -EIO; 1822 goto out_wipe_list; 1823 } 1824 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1825 sig_tmp_space, tag_11_contents_size); 1826 new_auth_tok->token.password.signature[ 1827 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1828 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1829 break; 1830 case ECRYPTFS_TAG_1_PACKET_TYPE: 1831 rc = parse_tag_1_packet(crypt_stat, 1832 (unsigned char *)&src[i], 1833 &auth_tok_list, &new_auth_tok, 1834 &packet_size, max_packet_size); 1835 if (rc) { 1836 ecryptfs_printk(KERN_ERR, "Error parsing " 1837 "tag 1 packet\n"); 1838 rc = -EIO; 1839 goto out_wipe_list; 1840 } 1841 i += packet_size; 1842 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1843 break; 1844 case ECRYPTFS_TAG_11_PACKET_TYPE: 1845 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1846 "(Tag 11 not allowed by itself)\n"); 1847 rc = -EIO; 1848 goto out_wipe_list; 1849 break; 1850 default: 1851 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1852 "of the file header; hex value of " 1853 "character is [0x%.2x]\n", i, src[i]); 1854 next_packet_is_auth_tok_packet = 0; 1855 } 1856 } 1857 if (list_empty(&auth_tok_list)) { 1858 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1859 "eCryptfs file; this is not supported in this version " 1860 "of the eCryptfs kernel module\n"); 1861 rc = -EINVAL; 1862 goto out; 1863 } 1864 /* auth_tok_list contains the set of authentication tokens 1865 * parsed from the metadata. We need to find a matching 1866 * authentication token that has the secret component(s) 1867 * necessary to decrypt the EFEK in the auth_tok parsed from 1868 * the metadata. There may be several potential matches, but 1869 * just one will be sufficient to decrypt to get the FEK. */ 1870 find_next_matching_auth_tok: 1871 found_auth_tok = 0; 1872 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1873 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1874 if (unlikely(ecryptfs_verbosity > 0)) { 1875 ecryptfs_printk(KERN_DEBUG, 1876 "Considering cadidate auth tok:\n"); 1877 ecryptfs_dump_auth_tok(candidate_auth_tok); 1878 } 1879 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1880 candidate_auth_tok); 1881 if (rc) { 1882 printk(KERN_ERR 1883 "Unrecognized candidate auth tok type: [%d]\n", 1884 candidate_auth_tok->token_type); 1885 rc = -EINVAL; 1886 goto out_wipe_list; 1887 } 1888 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1889 &matching_auth_tok, 1890 crypt_stat->mount_crypt_stat, 1891 candidate_auth_tok_sig); 1892 if (!rc) { 1893 found_auth_tok = 1; 1894 goto found_matching_auth_tok; 1895 } 1896 } 1897 if (!found_auth_tok) { 1898 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1899 "authentication token\n"); 1900 rc = -EIO; 1901 goto out_wipe_list; 1902 } 1903 found_matching_auth_tok: 1904 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1905 memcpy(&(candidate_auth_tok->token.private_key), 1906 &(matching_auth_tok->token.private_key), 1907 sizeof(struct ecryptfs_private_key)); 1908 up_write(&(auth_tok_key->sem)); 1909 key_put(auth_tok_key); 1910 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1911 crypt_stat); 1912 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1913 memcpy(&(candidate_auth_tok->token.password), 1914 &(matching_auth_tok->token.password), 1915 sizeof(struct ecryptfs_password)); 1916 up_write(&(auth_tok_key->sem)); 1917 key_put(auth_tok_key); 1918 rc = decrypt_passphrase_encrypted_session_key( 1919 candidate_auth_tok, crypt_stat); 1920 } else { 1921 up_write(&(auth_tok_key->sem)); 1922 key_put(auth_tok_key); 1923 rc = -EINVAL; 1924 } 1925 if (rc) { 1926 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1927 1928 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1929 "session key for authentication token with sig " 1930 "[%.*s]; rc = [%d]. Removing auth tok " 1931 "candidate from the list and searching for " 1932 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1933 candidate_auth_tok_sig, rc); 1934 list_for_each_entry_safe(auth_tok_list_item, 1935 auth_tok_list_item_tmp, 1936 &auth_tok_list, list) { 1937 if (candidate_auth_tok 1938 == &auth_tok_list_item->auth_tok) { 1939 list_del(&auth_tok_list_item->list); 1940 kmem_cache_free( 1941 ecryptfs_auth_tok_list_item_cache, 1942 auth_tok_list_item); 1943 goto find_next_matching_auth_tok; 1944 } 1945 } 1946 BUG(); 1947 } 1948 rc = ecryptfs_compute_root_iv(crypt_stat); 1949 if (rc) { 1950 ecryptfs_printk(KERN_ERR, "Error computing " 1951 "the root IV\n"); 1952 goto out_wipe_list; 1953 } 1954 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1955 if (rc) { 1956 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1957 "context for cipher [%s]; rc = [%d]\n", 1958 crypt_stat->cipher, rc); 1959 } 1960 out_wipe_list: 1961 wipe_auth_tok_list(&auth_tok_list); 1962 out: 1963 return rc; 1964 } 1965 1966 static int 1967 pki_encrypt_session_key(struct key *auth_tok_key, 1968 struct ecryptfs_auth_tok *auth_tok, 1969 struct ecryptfs_crypt_stat *crypt_stat, 1970 struct ecryptfs_key_record *key_rec) 1971 { 1972 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1973 char *payload = NULL; 1974 size_t payload_len = 0; 1975 struct ecryptfs_message *msg; 1976 int rc; 1977 1978 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1979 ecryptfs_code_for_cipher_string( 1980 crypt_stat->cipher, 1981 crypt_stat->key_size), 1982 crypt_stat, &payload, &payload_len); 1983 up_write(&(auth_tok_key->sem)); 1984 key_put(auth_tok_key); 1985 if (rc) { 1986 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1987 goto out; 1988 } 1989 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1990 if (rc) { 1991 ecryptfs_printk(KERN_ERR, "Error sending message to " 1992 "ecryptfsd\n"); 1993 goto out; 1994 } 1995 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1996 if (rc) { 1997 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 1998 "from the user space daemon\n"); 1999 rc = -EIO; 2000 goto out; 2001 } 2002 rc = parse_tag_67_packet(key_rec, msg); 2003 if (rc) 2004 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2005 kfree(msg); 2006 out: 2007 kfree(payload); 2008 return rc; 2009 } 2010 /** 2011 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2012 * @dest: Buffer into which to write the packet 2013 * @remaining_bytes: Maximum number of bytes that can be writtn 2014 * @auth_tok_key: The authentication token key to unlock and put when done with 2015 * @auth_tok 2016 * @auth_tok: The authentication token used for generating the tag 1 packet 2017 * @crypt_stat: The cryptographic context 2018 * @key_rec: The key record struct for the tag 1 packet 2019 * @packet_size: This function will write the number of bytes that end 2020 * up constituting the packet; set to zero on error 2021 * 2022 * Returns zero on success; non-zero on error. 2023 */ 2024 static int 2025 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2026 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2027 struct ecryptfs_crypt_stat *crypt_stat, 2028 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2029 { 2030 size_t i; 2031 size_t encrypted_session_key_valid = 0; 2032 size_t packet_size_length; 2033 size_t max_packet_size; 2034 int rc = 0; 2035 2036 (*packet_size) = 0; 2037 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2038 ECRYPTFS_SIG_SIZE); 2039 encrypted_session_key_valid = 0; 2040 for (i = 0; i < crypt_stat->key_size; i++) 2041 encrypted_session_key_valid |= 2042 auth_tok->session_key.encrypted_key[i]; 2043 if (encrypted_session_key_valid) { 2044 memcpy(key_rec->enc_key, 2045 auth_tok->session_key.encrypted_key, 2046 auth_tok->session_key.encrypted_key_size); 2047 up_write(&(auth_tok_key->sem)); 2048 key_put(auth_tok_key); 2049 goto encrypted_session_key_set; 2050 } 2051 if (auth_tok->session_key.encrypted_key_size == 0) 2052 auth_tok->session_key.encrypted_key_size = 2053 auth_tok->token.private_key.key_size; 2054 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2055 key_rec); 2056 if (rc) { 2057 printk(KERN_ERR "Failed to encrypt session key via a key " 2058 "module; rc = [%d]\n", rc); 2059 goto out; 2060 } 2061 if (ecryptfs_verbosity > 0) { 2062 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2063 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2064 } 2065 encrypted_session_key_set: 2066 /* This format is inspired by OpenPGP; see RFC 2440 2067 * packet tag 1 */ 2068 max_packet_size = (1 /* Tag 1 identifier */ 2069 + 3 /* Max Tag 1 packet size */ 2070 + 1 /* Version */ 2071 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2072 + 1 /* Cipher identifier */ 2073 + key_rec->enc_key_size); /* Encrypted key size */ 2074 if (max_packet_size > (*remaining_bytes)) { 2075 printk(KERN_ERR "Packet length larger than maximum allowable; " 2076 "need up to [%td] bytes, but there are only [%td] " 2077 "available\n", max_packet_size, (*remaining_bytes)); 2078 rc = -EINVAL; 2079 goto out; 2080 } 2081 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2082 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2083 (max_packet_size - 4), 2084 &packet_size_length); 2085 if (rc) { 2086 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2087 "header; cannot generate packet length\n"); 2088 goto out; 2089 } 2090 (*packet_size) += packet_size_length; 2091 dest[(*packet_size)++] = 0x03; /* version 3 */ 2092 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2093 (*packet_size) += ECRYPTFS_SIG_SIZE; 2094 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2095 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2096 key_rec->enc_key_size); 2097 (*packet_size) += key_rec->enc_key_size; 2098 out: 2099 if (rc) 2100 (*packet_size) = 0; 2101 else 2102 (*remaining_bytes) -= (*packet_size); 2103 return rc; 2104 } 2105 2106 /** 2107 * write_tag_11_packet 2108 * @dest: Target into which Tag 11 packet is to be written 2109 * @remaining_bytes: Maximum packet length 2110 * @contents: Byte array of contents to copy in 2111 * @contents_length: Number of bytes in contents 2112 * @packet_length: Length of the Tag 11 packet written; zero on error 2113 * 2114 * Returns zero on success; non-zero on error. 2115 */ 2116 static int 2117 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2118 size_t contents_length, size_t *packet_length) 2119 { 2120 size_t packet_size_length; 2121 size_t max_packet_size; 2122 int rc = 0; 2123 2124 (*packet_length) = 0; 2125 /* This format is inspired by OpenPGP; see RFC 2440 2126 * packet tag 11 */ 2127 max_packet_size = (1 /* Tag 11 identifier */ 2128 + 3 /* Max Tag 11 packet size */ 2129 + 1 /* Binary format specifier */ 2130 + 1 /* Filename length */ 2131 + 8 /* Filename ("_CONSOLE") */ 2132 + 4 /* Modification date */ 2133 + contents_length); /* Literal data */ 2134 if (max_packet_size > (*remaining_bytes)) { 2135 printk(KERN_ERR "Packet length larger than maximum allowable; " 2136 "need up to [%td] bytes, but there are only [%td] " 2137 "available\n", max_packet_size, (*remaining_bytes)); 2138 rc = -EINVAL; 2139 goto out; 2140 } 2141 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2142 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2143 (max_packet_size - 4), 2144 &packet_size_length); 2145 if (rc) { 2146 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2147 "generate packet length. rc = [%d]\n", rc); 2148 goto out; 2149 } 2150 (*packet_length) += packet_size_length; 2151 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2152 dest[(*packet_length)++] = 8; 2153 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2154 (*packet_length) += 8; 2155 memset(&dest[(*packet_length)], 0x00, 4); 2156 (*packet_length) += 4; 2157 memcpy(&dest[(*packet_length)], contents, contents_length); 2158 (*packet_length) += contents_length; 2159 out: 2160 if (rc) 2161 (*packet_length) = 0; 2162 else 2163 (*remaining_bytes) -= (*packet_length); 2164 return rc; 2165 } 2166 2167 /** 2168 * write_tag_3_packet 2169 * @dest: Buffer into which to write the packet 2170 * @remaining_bytes: Maximum number of bytes that can be written 2171 * @auth_tok: Authentication token 2172 * @crypt_stat: The cryptographic context 2173 * @key_rec: encrypted key 2174 * @packet_size: This function will write the number of bytes that end 2175 * up constituting the packet; set to zero on error 2176 * 2177 * Returns zero on success; non-zero on error. 2178 */ 2179 static int 2180 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2181 struct ecryptfs_auth_tok *auth_tok, 2182 struct ecryptfs_crypt_stat *crypt_stat, 2183 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2184 { 2185 size_t i; 2186 size_t encrypted_session_key_valid = 0; 2187 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2188 struct scatterlist dst_sg[2]; 2189 struct scatterlist src_sg[2]; 2190 struct mutex *tfm_mutex = NULL; 2191 u8 cipher_code; 2192 size_t packet_size_length; 2193 size_t max_packet_size; 2194 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2195 crypt_stat->mount_crypt_stat; 2196 struct blkcipher_desc desc = { 2197 .tfm = NULL, 2198 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 2199 }; 2200 int rc = 0; 2201 2202 (*packet_size) = 0; 2203 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2204 ECRYPTFS_SIG_SIZE); 2205 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 2206 crypt_stat->cipher); 2207 if (unlikely(rc)) { 2208 printk(KERN_ERR "Internal error whilst attempting to get " 2209 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2210 crypt_stat->cipher, rc); 2211 goto out; 2212 } 2213 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2214 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm); 2215 2216 printk(KERN_WARNING "No key size specified at mount; " 2217 "defaulting to [%d]\n", alg->max_keysize); 2218 mount_crypt_stat->global_default_cipher_key_size = 2219 alg->max_keysize; 2220 } 2221 if (crypt_stat->key_size == 0) 2222 crypt_stat->key_size = 2223 mount_crypt_stat->global_default_cipher_key_size; 2224 if (auth_tok->session_key.encrypted_key_size == 0) 2225 auth_tok->session_key.encrypted_key_size = 2226 crypt_stat->key_size; 2227 if (crypt_stat->key_size == 24 2228 && strcmp("aes", crypt_stat->cipher) == 0) { 2229 memset((crypt_stat->key + 24), 0, 8); 2230 auth_tok->session_key.encrypted_key_size = 32; 2231 } else 2232 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2233 key_rec->enc_key_size = 2234 auth_tok->session_key.encrypted_key_size; 2235 encrypted_session_key_valid = 0; 2236 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2237 encrypted_session_key_valid |= 2238 auth_tok->session_key.encrypted_key[i]; 2239 if (encrypted_session_key_valid) { 2240 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2241 "using auth_tok->session_key.encrypted_key, " 2242 "where key_rec->enc_key_size = [%zd]\n", 2243 key_rec->enc_key_size); 2244 memcpy(key_rec->enc_key, 2245 auth_tok->session_key.encrypted_key, 2246 key_rec->enc_key_size); 2247 goto encrypted_session_key_set; 2248 } 2249 if (auth_tok->token.password.flags & 2250 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2251 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2252 "session key encryption key of size [%d]\n", 2253 auth_tok->token.password. 2254 session_key_encryption_key_bytes); 2255 memcpy(session_key_encryption_key, 2256 auth_tok->token.password.session_key_encryption_key, 2257 crypt_stat->key_size); 2258 ecryptfs_printk(KERN_DEBUG, 2259 "Cached session key encryption key:\n"); 2260 if (ecryptfs_verbosity > 0) 2261 ecryptfs_dump_hex(session_key_encryption_key, 16); 2262 } 2263 if (unlikely(ecryptfs_verbosity > 0)) { 2264 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2265 ecryptfs_dump_hex(session_key_encryption_key, 16); 2266 } 2267 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2268 src_sg, 2); 2269 if (rc < 1 || rc > 2) { 2270 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2271 "for crypt_stat session key; expected rc = 1; " 2272 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2273 rc, key_rec->enc_key_size); 2274 rc = -ENOMEM; 2275 goto out; 2276 } 2277 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2278 dst_sg, 2); 2279 if (rc < 1 || rc > 2) { 2280 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2281 "for crypt_stat encrypted session key; " 2282 "expected rc = 1; got rc = [%d]. " 2283 "key_rec->enc_key_size = [%zd]\n", rc, 2284 key_rec->enc_key_size); 2285 rc = -ENOMEM; 2286 goto out; 2287 } 2288 mutex_lock(tfm_mutex); 2289 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key, 2290 crypt_stat->key_size); 2291 if (rc < 0) { 2292 mutex_unlock(tfm_mutex); 2293 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2294 "context; rc = [%d]\n", rc); 2295 goto out; 2296 } 2297 rc = 0; 2298 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2299 crypt_stat->key_size); 2300 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg, 2301 (*key_rec).enc_key_size); 2302 mutex_unlock(tfm_mutex); 2303 if (rc) { 2304 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2305 goto out; 2306 } 2307 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2308 if (ecryptfs_verbosity > 0) { 2309 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2310 key_rec->enc_key_size); 2311 ecryptfs_dump_hex(key_rec->enc_key, 2312 key_rec->enc_key_size); 2313 } 2314 encrypted_session_key_set: 2315 /* This format is inspired by OpenPGP; see RFC 2440 2316 * packet tag 3 */ 2317 max_packet_size = (1 /* Tag 3 identifier */ 2318 + 3 /* Max Tag 3 packet size */ 2319 + 1 /* Version */ 2320 + 1 /* Cipher code */ 2321 + 1 /* S2K specifier */ 2322 + 1 /* Hash identifier */ 2323 + ECRYPTFS_SALT_SIZE /* Salt */ 2324 + 1 /* Hash iterations */ 2325 + key_rec->enc_key_size); /* Encrypted key size */ 2326 if (max_packet_size > (*remaining_bytes)) { 2327 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2328 "there are only [%td] available\n", max_packet_size, 2329 (*remaining_bytes)); 2330 rc = -EINVAL; 2331 goto out; 2332 } 2333 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2334 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2335 * to get the number of octets in the actual Tag 3 packet */ 2336 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2337 (max_packet_size - 4), 2338 &packet_size_length); 2339 if (rc) { 2340 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2341 "generate packet length. rc = [%d]\n", rc); 2342 goto out; 2343 } 2344 (*packet_size) += packet_size_length; 2345 dest[(*packet_size)++] = 0x04; /* version 4 */ 2346 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2347 * specified with strings */ 2348 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2349 crypt_stat->key_size); 2350 if (cipher_code == 0) { 2351 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2352 "cipher [%s]\n", crypt_stat->cipher); 2353 rc = -EINVAL; 2354 goto out; 2355 } 2356 dest[(*packet_size)++] = cipher_code; 2357 dest[(*packet_size)++] = 0x03; /* S2K */ 2358 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2359 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2360 ECRYPTFS_SALT_SIZE); 2361 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2362 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2363 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2364 key_rec->enc_key_size); 2365 (*packet_size) += key_rec->enc_key_size; 2366 out: 2367 if (rc) 2368 (*packet_size) = 0; 2369 else 2370 (*remaining_bytes) -= (*packet_size); 2371 return rc; 2372 } 2373 2374 struct kmem_cache *ecryptfs_key_record_cache; 2375 2376 /** 2377 * ecryptfs_generate_key_packet_set 2378 * @dest_base: Virtual address from which to write the key record set 2379 * @crypt_stat: The cryptographic context from which the 2380 * authentication tokens will be retrieved 2381 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2382 * for the global parameters 2383 * @len: The amount written 2384 * @max: The maximum amount of data allowed to be written 2385 * 2386 * Generates a key packet set and writes it to the virtual address 2387 * passed in. 2388 * 2389 * Returns zero on success; non-zero on error. 2390 */ 2391 int 2392 ecryptfs_generate_key_packet_set(char *dest_base, 2393 struct ecryptfs_crypt_stat *crypt_stat, 2394 struct dentry *ecryptfs_dentry, size_t *len, 2395 size_t max) 2396 { 2397 struct ecryptfs_auth_tok *auth_tok; 2398 struct key *auth_tok_key = NULL; 2399 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2400 &ecryptfs_superblock_to_private( 2401 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2402 size_t written; 2403 struct ecryptfs_key_record *key_rec; 2404 struct ecryptfs_key_sig *key_sig; 2405 int rc = 0; 2406 2407 (*len) = 0; 2408 mutex_lock(&crypt_stat->keysig_list_mutex); 2409 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2410 if (!key_rec) { 2411 rc = -ENOMEM; 2412 goto out; 2413 } 2414 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2415 crypt_stat_list) { 2416 memset(key_rec, 0, sizeof(*key_rec)); 2417 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2418 &auth_tok, 2419 mount_crypt_stat, 2420 key_sig->keysig); 2421 if (rc) { 2422 printk(KERN_WARNING "Unable to retrieve auth tok with " 2423 "sig = [%s]\n", key_sig->keysig); 2424 rc = process_find_global_auth_tok_for_sig_err(rc); 2425 goto out_free; 2426 } 2427 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2428 rc = write_tag_3_packet((dest_base + (*len)), 2429 &max, auth_tok, 2430 crypt_stat, key_rec, 2431 &written); 2432 up_write(&(auth_tok_key->sem)); 2433 key_put(auth_tok_key); 2434 if (rc) { 2435 ecryptfs_printk(KERN_WARNING, "Error " 2436 "writing tag 3 packet\n"); 2437 goto out_free; 2438 } 2439 (*len) += written; 2440 /* Write auth tok signature packet */ 2441 rc = write_tag_11_packet((dest_base + (*len)), &max, 2442 key_rec->sig, 2443 ECRYPTFS_SIG_SIZE, &written); 2444 if (rc) { 2445 ecryptfs_printk(KERN_ERR, "Error writing " 2446 "auth tok signature packet\n"); 2447 goto out_free; 2448 } 2449 (*len) += written; 2450 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2451 rc = write_tag_1_packet(dest_base + (*len), &max, 2452 auth_tok_key, auth_tok, 2453 crypt_stat, key_rec, &written); 2454 if (rc) { 2455 ecryptfs_printk(KERN_WARNING, "Error " 2456 "writing tag 1 packet\n"); 2457 goto out_free; 2458 } 2459 (*len) += written; 2460 } else { 2461 up_write(&(auth_tok_key->sem)); 2462 key_put(auth_tok_key); 2463 ecryptfs_printk(KERN_WARNING, "Unsupported " 2464 "authentication token type\n"); 2465 rc = -EINVAL; 2466 goto out_free; 2467 } 2468 } 2469 if (likely(max > 0)) { 2470 dest_base[(*len)] = 0x00; 2471 } else { 2472 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2473 rc = -EIO; 2474 } 2475 out_free: 2476 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2477 out: 2478 if (rc) 2479 (*len) = 0; 2480 mutex_unlock(&crypt_stat->keysig_list_mutex); 2481 return rc; 2482 } 2483 2484 struct kmem_cache *ecryptfs_key_sig_cache; 2485 2486 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2487 { 2488 struct ecryptfs_key_sig *new_key_sig; 2489 2490 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2491 if (!new_key_sig) { 2492 printk(KERN_ERR 2493 "Error allocating from ecryptfs_key_sig_cache\n"); 2494 return -ENOMEM; 2495 } 2496 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2497 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2498 /* Caller must hold keysig_list_mutex */ 2499 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2500 2501 return 0; 2502 } 2503 2504 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2505 2506 int 2507 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2508 char *sig, u32 global_auth_tok_flags) 2509 { 2510 struct ecryptfs_global_auth_tok *new_auth_tok; 2511 int rc = 0; 2512 2513 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2514 GFP_KERNEL); 2515 if (!new_auth_tok) { 2516 rc = -ENOMEM; 2517 printk(KERN_ERR "Error allocating from " 2518 "ecryptfs_global_auth_tok_cache\n"); 2519 goto out; 2520 } 2521 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2522 new_auth_tok->flags = global_auth_tok_flags; 2523 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2524 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2525 list_add(&new_auth_tok->mount_crypt_stat_list, 2526 &mount_crypt_stat->global_auth_tok_list); 2527 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2528 out: 2529 return rc; 2530 } 2531 2532