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 = (1 /* Tag 70 identifier */ 683 + 3 /* Max Tag 70 packet size */ 684 + ECRYPTFS_SIG_SIZE /* FNEK sig */ 685 + 1 /* Cipher identifier */ 686 + s->block_aligned_filename_size); 687 if (dest == NULL) { 688 (*packet_size) = s->max_packet_size; 689 goto out_unlock; 690 } 691 if (s->max_packet_size > (*remaining_bytes)) { 692 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 693 "[%zd] available\n", __func__, s->max_packet_size, 694 (*remaining_bytes)); 695 rc = -EINVAL; 696 goto out_unlock; 697 } 698 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 699 GFP_KERNEL); 700 if (!s->block_aligned_filename) { 701 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 702 "kzalloc [%zd] bytes\n", __func__, 703 s->block_aligned_filename_size); 704 rc = -ENOMEM; 705 goto out_unlock; 706 } 707 s->i = 0; 708 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 709 rc = ecryptfs_write_packet_length(&dest[s->i], 710 (ECRYPTFS_SIG_SIZE 711 + 1 /* Cipher code */ 712 + s->block_aligned_filename_size), 713 &s->packet_size_len); 714 if (rc) { 715 printk(KERN_ERR "%s: Error generating tag 70 packet " 716 "header; cannot generate packet length; rc = [%d]\n", 717 __func__, rc); 718 goto out_free_unlock; 719 } 720 s->i += s->packet_size_len; 721 ecryptfs_from_hex(&dest[s->i], 722 mount_crypt_stat->global_default_fnek_sig, 723 ECRYPTFS_SIG_SIZE); 724 s->i += ECRYPTFS_SIG_SIZE; 725 s->cipher_code = ecryptfs_code_for_cipher_string( 726 mount_crypt_stat->global_default_fn_cipher_name, 727 mount_crypt_stat->global_default_fn_cipher_key_bytes); 728 if (s->cipher_code == 0) { 729 printk(KERN_WARNING "%s: Unable to generate code for " 730 "cipher [%s] with key bytes [%zd]\n", __func__, 731 mount_crypt_stat->global_default_fn_cipher_name, 732 mount_crypt_stat->global_default_fn_cipher_key_bytes); 733 rc = -EINVAL; 734 goto out_free_unlock; 735 } 736 dest[s->i++] = s->cipher_code; 737 /* TODO: Support other key modules than passphrase for 738 * filename encryption */ 739 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 740 rc = -EOPNOTSUPP; 741 printk(KERN_INFO "%s: Filename encryption only supports " 742 "password tokens\n", __func__); 743 goto out_free_unlock; 744 } 745 sg_init_one( 746 &s->hash_sg, 747 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 748 s->auth_tok->token.password.session_key_encryption_key_bytes); 749 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 750 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0, 751 CRYPTO_ALG_ASYNC); 752 if (IS_ERR(s->hash_desc.tfm)) { 753 rc = PTR_ERR(s->hash_desc.tfm); 754 printk(KERN_ERR "%s: Error attempting to " 755 "allocate hash crypto context; rc = [%d]\n", 756 __func__, rc); 757 goto out_free_unlock; 758 } 759 rc = crypto_hash_init(&s->hash_desc); 760 if (rc) { 761 printk(KERN_ERR 762 "%s: Error initializing crypto hash; rc = [%d]\n", 763 __func__, rc); 764 goto out_release_free_unlock; 765 } 766 rc = crypto_hash_update( 767 &s->hash_desc, &s->hash_sg, 768 s->auth_tok->token.password.session_key_encryption_key_bytes); 769 if (rc) { 770 printk(KERN_ERR 771 "%s: Error updating crypto hash; rc = [%d]\n", 772 __func__, rc); 773 goto out_release_free_unlock; 774 } 775 rc = crypto_hash_final(&s->hash_desc, s->hash); 776 if (rc) { 777 printk(KERN_ERR 778 "%s: Error finalizing crypto hash; rc = [%d]\n", 779 __func__, rc); 780 goto out_release_free_unlock; 781 } 782 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 783 s->block_aligned_filename[s->j] = 784 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 785 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 786 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 787 sg_init_one(&s->hash_sg, (u8 *)s->hash, 788 ECRYPTFS_TAG_70_DIGEST_SIZE); 789 rc = crypto_hash_init(&s->hash_desc); 790 if (rc) { 791 printk(KERN_ERR 792 "%s: Error initializing crypto hash; " 793 "rc = [%d]\n", __func__, rc); 794 goto out_release_free_unlock; 795 } 796 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg, 797 ECRYPTFS_TAG_70_DIGEST_SIZE); 798 if (rc) { 799 printk(KERN_ERR 800 "%s: Error updating crypto hash; " 801 "rc = [%d]\n", __func__, rc); 802 goto out_release_free_unlock; 803 } 804 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash); 805 if (rc) { 806 printk(KERN_ERR 807 "%s: Error finalizing crypto hash; " 808 "rc = [%d]\n", __func__, rc); 809 goto out_release_free_unlock; 810 } 811 memcpy(s->hash, s->tmp_hash, 812 ECRYPTFS_TAG_70_DIGEST_SIZE); 813 } 814 if (s->block_aligned_filename[s->j] == '\0') 815 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 816 } 817 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 818 filename_size); 819 rc = virt_to_scatterlist(s->block_aligned_filename, 820 s->block_aligned_filename_size, s->src_sg, 2); 821 if (rc < 1) { 822 printk(KERN_ERR "%s: Internal error whilst attempting to " 823 "convert filename memory to scatterlist; rc = [%d]. " 824 "block_aligned_filename_size = [%zd]\n", __func__, rc, 825 s->block_aligned_filename_size); 826 goto out_release_free_unlock; 827 } 828 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 829 s->dst_sg, 2); 830 if (rc < 1) { 831 printk(KERN_ERR "%s: Internal error whilst attempting to " 832 "convert encrypted filename memory to scatterlist; " 833 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 834 __func__, rc, s->block_aligned_filename_size); 835 goto out_release_free_unlock; 836 } 837 /* The characters in the first block effectively do the job 838 * of the IV here, so we just use 0's for the IV. Note the 839 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 840 * >= ECRYPTFS_MAX_IV_BYTES. */ 841 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 842 s->desc.info = s->iv; 843 rc = crypto_blkcipher_setkey( 844 s->desc.tfm, 845 s->auth_tok->token.password.session_key_encryption_key, 846 mount_crypt_stat->global_default_fn_cipher_key_bytes); 847 if (rc < 0) { 848 printk(KERN_ERR "%s: Error setting key for crypto context; " 849 "rc = [%d]. s->auth_tok->token.password.session_key_" 850 "encryption_key = [0x%p]; mount_crypt_stat->" 851 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 852 rc, 853 s->auth_tok->token.password.session_key_encryption_key, 854 mount_crypt_stat->global_default_fn_cipher_key_bytes); 855 goto out_release_free_unlock; 856 } 857 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg, 858 s->block_aligned_filename_size); 859 if (rc) { 860 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 861 "rc = [%d]\n", __func__, rc); 862 goto out_release_free_unlock; 863 } 864 s->i += s->block_aligned_filename_size; 865 (*packet_size) = s->i; 866 (*remaining_bytes) -= (*packet_size); 867 out_release_free_unlock: 868 crypto_free_hash(s->hash_desc.tfm); 869 out_free_unlock: 870 kzfree(s->block_aligned_filename); 871 out_unlock: 872 mutex_unlock(s->tfm_mutex); 873 out: 874 if (auth_tok_key) { 875 up_write(&(auth_tok_key->sem)); 876 key_put(auth_tok_key); 877 } 878 kfree(s); 879 return rc; 880 } 881 882 struct ecryptfs_parse_tag_70_packet_silly_stack { 883 u8 cipher_code; 884 size_t max_packet_size; 885 size_t packet_size_len; 886 size_t parsed_tag_70_packet_size; 887 size_t block_aligned_filename_size; 888 size_t block_size; 889 size_t i; 890 struct mutex *tfm_mutex; 891 char *decrypted_filename; 892 struct ecryptfs_auth_tok *auth_tok; 893 struct scatterlist src_sg[2]; 894 struct scatterlist dst_sg[2]; 895 struct blkcipher_desc desc; 896 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 897 char iv[ECRYPTFS_MAX_IV_BYTES]; 898 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE]; 899 }; 900 901 /** 902 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 903 * @filename: This function kmalloc's the memory for the filename 904 * @filename_size: This function sets this to the amount of memory 905 * kmalloc'd for the filename 906 * @packet_size: This function sets this to the the number of octets 907 * in the packet parsed 908 * @mount_crypt_stat: The mount-wide cryptographic context 909 * @data: The memory location containing the start of the tag 70 910 * packet 911 * @max_packet_size: The maximum legal size of the packet to be parsed 912 * from @data 913 * 914 * Returns zero on success; non-zero otherwise 915 */ 916 int 917 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 918 size_t *packet_size, 919 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 920 char *data, size_t max_packet_size) 921 { 922 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 923 struct key *auth_tok_key = NULL; 924 int rc = 0; 925 926 (*packet_size) = 0; 927 (*filename_size) = 0; 928 (*filename) = NULL; 929 s = kmalloc(sizeof(*s), GFP_KERNEL); 930 if (!s) { 931 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 932 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 933 rc = -ENOMEM; 934 goto out; 935 } 936 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 937 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) { 938 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 939 "at least [%d]\n", __func__, max_packet_size, 940 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)); 941 rc = -EINVAL; 942 goto out; 943 } 944 /* Octet 0: Tag 70 identifier 945 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 946 * and block-aligned encrypted filename size) 947 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 948 * Octet N2-N3: Cipher identifier (1 octet) 949 * Octets N3-N4: Block-aligned encrypted filename 950 * - Consists of a minimum number of random numbers, a \0 951 * separator, and then the filename */ 952 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 953 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 954 "tag [0x%.2x]\n", __func__, 955 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 956 rc = -EINVAL; 957 goto out; 958 } 959 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 960 &s->parsed_tag_70_packet_size, 961 &s->packet_size_len); 962 if (rc) { 963 printk(KERN_WARNING "%s: Error parsing packet length; " 964 "rc = [%d]\n", __func__, rc); 965 goto out; 966 } 967 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 968 - ECRYPTFS_SIG_SIZE - 1); 969 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 970 > max_packet_size) { 971 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 972 "size is [%zd]\n", __func__, max_packet_size, 973 (1 + s->packet_size_len + 1 974 + s->block_aligned_filename_size)); 975 rc = -EINVAL; 976 goto out; 977 } 978 (*packet_size) += s->packet_size_len; 979 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 980 ECRYPTFS_SIG_SIZE); 981 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 982 (*packet_size) += ECRYPTFS_SIG_SIZE; 983 s->cipher_code = data[(*packet_size)++]; 984 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 985 if (rc) { 986 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 987 __func__, s->cipher_code); 988 goto out; 989 } 990 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 991 &s->auth_tok, mount_crypt_stat, 992 s->fnek_sig_hex); 993 if (rc) { 994 printk(KERN_ERR "%s: Error attempting to find auth tok for " 995 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 996 rc); 997 goto out; 998 } 999 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm, 1000 &s->tfm_mutex, 1001 s->cipher_string); 1002 if (unlikely(rc)) { 1003 printk(KERN_ERR "Internal error whilst attempting to get " 1004 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1005 s->cipher_string, rc); 1006 goto out; 1007 } 1008 mutex_lock(s->tfm_mutex); 1009 rc = virt_to_scatterlist(&data[(*packet_size)], 1010 s->block_aligned_filename_size, s->src_sg, 2); 1011 if (rc < 1) { 1012 printk(KERN_ERR "%s: Internal error whilst attempting to " 1013 "convert encrypted filename memory to scatterlist; " 1014 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1015 __func__, rc, s->block_aligned_filename_size); 1016 goto out_unlock; 1017 } 1018 (*packet_size) += s->block_aligned_filename_size; 1019 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 1020 GFP_KERNEL); 1021 if (!s->decrypted_filename) { 1022 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1023 "kmalloc [%zd] bytes\n", __func__, 1024 s->block_aligned_filename_size); 1025 rc = -ENOMEM; 1026 goto out_unlock; 1027 } 1028 rc = virt_to_scatterlist(s->decrypted_filename, 1029 s->block_aligned_filename_size, s->dst_sg, 2); 1030 if (rc < 1) { 1031 printk(KERN_ERR "%s: Internal error whilst attempting to " 1032 "convert decrypted filename memory to scatterlist; " 1033 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1034 __func__, rc, s->block_aligned_filename_size); 1035 goto out_free_unlock; 1036 } 1037 /* The characters in the first block effectively do the job of 1038 * the IV here, so we just use 0's for the IV. Note the 1039 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1040 * >= ECRYPTFS_MAX_IV_BYTES. */ 1041 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); 1042 s->desc.info = s->iv; 1043 /* TODO: Support other key modules than passphrase for 1044 * filename encryption */ 1045 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1046 rc = -EOPNOTSUPP; 1047 printk(KERN_INFO "%s: Filename encryption only supports " 1048 "password tokens\n", __func__); 1049 goto out_free_unlock; 1050 } 1051 rc = crypto_blkcipher_setkey( 1052 s->desc.tfm, 1053 s->auth_tok->token.password.session_key_encryption_key, 1054 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1055 if (rc < 0) { 1056 printk(KERN_ERR "%s: Error setting key for crypto context; " 1057 "rc = [%d]. s->auth_tok->token.password.session_key_" 1058 "encryption_key = [0x%p]; mount_crypt_stat->" 1059 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1060 rc, 1061 s->auth_tok->token.password.session_key_encryption_key, 1062 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1063 goto out_free_unlock; 1064 } 1065 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg, 1066 s->block_aligned_filename_size); 1067 if (rc) { 1068 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1069 "rc = [%d]\n", __func__, rc); 1070 goto out_free_unlock; 1071 } 1072 s->i = 0; 1073 while (s->decrypted_filename[s->i] != '\0' 1074 && s->i < s->block_aligned_filename_size) 1075 s->i++; 1076 if (s->i == s->block_aligned_filename_size) { 1077 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1078 "find valid separator between random characters and " 1079 "the filename\n", __func__); 1080 rc = -EINVAL; 1081 goto out_free_unlock; 1082 } 1083 s->i++; 1084 (*filename_size) = (s->block_aligned_filename_size - s->i); 1085 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1086 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1087 "invalid\n", __func__, (*filename_size)); 1088 rc = -EINVAL; 1089 goto out_free_unlock; 1090 } 1091 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1092 if (!(*filename)) { 1093 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1094 "kmalloc [%zd] bytes\n", __func__, 1095 ((*filename_size) + 1)); 1096 rc = -ENOMEM; 1097 goto out_free_unlock; 1098 } 1099 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1100 (*filename)[(*filename_size)] = '\0'; 1101 out_free_unlock: 1102 kfree(s->decrypted_filename); 1103 out_unlock: 1104 mutex_unlock(s->tfm_mutex); 1105 out: 1106 if (rc) { 1107 (*packet_size) = 0; 1108 (*filename_size) = 0; 1109 (*filename) = NULL; 1110 } 1111 if (auth_tok_key) { 1112 up_write(&(auth_tok_key->sem)); 1113 key_put(auth_tok_key); 1114 } 1115 kfree(s); 1116 return rc; 1117 } 1118 1119 static int 1120 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1121 { 1122 int rc = 0; 1123 1124 (*sig) = NULL; 1125 switch (auth_tok->token_type) { 1126 case ECRYPTFS_PASSWORD: 1127 (*sig) = auth_tok->token.password.signature; 1128 break; 1129 case ECRYPTFS_PRIVATE_KEY: 1130 (*sig) = auth_tok->token.private_key.signature; 1131 break; 1132 default: 1133 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1134 auth_tok->token_type); 1135 rc = -EINVAL; 1136 } 1137 return rc; 1138 } 1139 1140 /** 1141 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1142 * @auth_tok: The key authentication token used to decrypt the session key 1143 * @crypt_stat: The cryptographic context 1144 * 1145 * Returns zero on success; non-zero error otherwise. 1146 */ 1147 static int 1148 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1149 struct ecryptfs_crypt_stat *crypt_stat) 1150 { 1151 u8 cipher_code = 0; 1152 struct ecryptfs_msg_ctx *msg_ctx; 1153 struct ecryptfs_message *msg = NULL; 1154 char *auth_tok_sig; 1155 char *payload; 1156 size_t payload_len; 1157 int rc; 1158 1159 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1160 if (rc) { 1161 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1162 auth_tok->token_type); 1163 goto out; 1164 } 1165 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1166 &payload, &payload_len); 1167 if (rc) { 1168 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1169 goto out; 1170 } 1171 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1172 if (rc) { 1173 ecryptfs_printk(KERN_ERR, "Error sending message to " 1174 "ecryptfsd\n"); 1175 goto out; 1176 } 1177 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1178 if (rc) { 1179 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1180 "from the user space daemon\n"); 1181 rc = -EIO; 1182 goto out; 1183 } 1184 rc = parse_tag_65_packet(&(auth_tok->session_key), 1185 &cipher_code, msg); 1186 if (rc) { 1187 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1188 rc); 1189 goto out; 1190 } 1191 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1192 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1193 auth_tok->session_key.decrypted_key_size); 1194 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1195 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1196 if (rc) { 1197 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1198 cipher_code) 1199 goto out; 1200 } 1201 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1202 if (ecryptfs_verbosity > 0) { 1203 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1204 ecryptfs_dump_hex(crypt_stat->key, 1205 crypt_stat->key_size); 1206 } 1207 out: 1208 if (msg) 1209 kfree(msg); 1210 return rc; 1211 } 1212 1213 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1214 { 1215 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1216 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1217 1218 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1219 auth_tok_list_head, list) { 1220 list_del(&auth_tok_list_item->list); 1221 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1222 auth_tok_list_item); 1223 } 1224 } 1225 1226 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1227 1228 /** 1229 * parse_tag_1_packet 1230 * @crypt_stat: The cryptographic context to modify based on packet contents 1231 * @data: The raw bytes of the packet. 1232 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1233 * a new authentication token will be placed at the 1234 * end of this list for this packet. 1235 * @new_auth_tok: Pointer to a pointer to memory that this function 1236 * allocates; sets the memory address of the pointer to 1237 * NULL on error. This object is added to the 1238 * auth_tok_list. 1239 * @packet_size: This function writes the size of the parsed packet 1240 * into this memory location; zero on error. 1241 * @max_packet_size: The maximum allowable packet size 1242 * 1243 * Returns zero on success; non-zero on error. 1244 */ 1245 static int 1246 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1247 unsigned char *data, struct list_head *auth_tok_list, 1248 struct ecryptfs_auth_tok **new_auth_tok, 1249 size_t *packet_size, size_t max_packet_size) 1250 { 1251 size_t body_size; 1252 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1253 size_t length_size; 1254 int rc = 0; 1255 1256 (*packet_size) = 0; 1257 (*new_auth_tok) = NULL; 1258 /** 1259 * This format is inspired by OpenPGP; see RFC 2440 1260 * packet tag 1 1261 * 1262 * Tag 1 identifier (1 byte) 1263 * Max Tag 1 packet size (max 3 bytes) 1264 * Version (1 byte) 1265 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1266 * Cipher identifier (1 byte) 1267 * Encrypted key size (arbitrary) 1268 * 1269 * 12 bytes minimum packet size 1270 */ 1271 if (unlikely(max_packet_size < 12)) { 1272 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1273 rc = -EINVAL; 1274 goto out; 1275 } 1276 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1277 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1278 ECRYPTFS_TAG_1_PACKET_TYPE); 1279 rc = -EINVAL; 1280 goto out; 1281 } 1282 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1283 * at end of function upon failure */ 1284 auth_tok_list_item = 1285 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1286 GFP_KERNEL); 1287 if (!auth_tok_list_item) { 1288 printk(KERN_ERR "Unable to allocate memory\n"); 1289 rc = -ENOMEM; 1290 goto out; 1291 } 1292 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1293 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1294 &length_size); 1295 if (rc) { 1296 printk(KERN_WARNING "Error parsing packet length; " 1297 "rc = [%d]\n", rc); 1298 goto out_free; 1299 } 1300 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1301 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1302 rc = -EINVAL; 1303 goto out_free; 1304 } 1305 (*packet_size) += length_size; 1306 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1307 printk(KERN_WARNING "Packet size exceeds max\n"); 1308 rc = -EINVAL; 1309 goto out_free; 1310 } 1311 if (unlikely(data[(*packet_size)++] != 0x03)) { 1312 printk(KERN_WARNING "Unknown version number [%d]\n", 1313 data[(*packet_size) - 1]); 1314 rc = -EINVAL; 1315 goto out_free; 1316 } 1317 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1318 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1319 *packet_size += ECRYPTFS_SIG_SIZE; 1320 /* This byte is skipped because the kernel does not need to 1321 * know which public key encryption algorithm was used */ 1322 (*packet_size)++; 1323 (*new_auth_tok)->session_key.encrypted_key_size = 1324 body_size - (ECRYPTFS_SIG_SIZE + 2); 1325 if ((*new_auth_tok)->session_key.encrypted_key_size 1326 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1327 printk(KERN_WARNING "Tag 1 packet contains key larger " 1328 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); 1329 rc = -EINVAL; 1330 goto out; 1331 } 1332 memcpy((*new_auth_tok)->session_key.encrypted_key, 1333 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1334 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1335 (*new_auth_tok)->session_key.flags &= 1336 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1337 (*new_auth_tok)->session_key.flags |= 1338 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1339 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1340 (*new_auth_tok)->flags = 0; 1341 (*new_auth_tok)->session_key.flags &= 1342 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1343 (*new_auth_tok)->session_key.flags &= 1344 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1345 list_add(&auth_tok_list_item->list, auth_tok_list); 1346 goto out; 1347 out_free: 1348 (*new_auth_tok) = NULL; 1349 memset(auth_tok_list_item, 0, 1350 sizeof(struct ecryptfs_auth_tok_list_item)); 1351 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1352 auth_tok_list_item); 1353 out: 1354 if (rc) 1355 (*packet_size) = 0; 1356 return rc; 1357 } 1358 1359 /** 1360 * parse_tag_3_packet 1361 * @crypt_stat: The cryptographic context to modify based on packet 1362 * contents. 1363 * @data: The raw bytes of the packet. 1364 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1365 * a new authentication token will be placed at the end 1366 * of this list for this packet. 1367 * @new_auth_tok: Pointer to a pointer to memory that this function 1368 * allocates; sets the memory address of the pointer to 1369 * NULL on error. This object is added to the 1370 * auth_tok_list. 1371 * @packet_size: This function writes the size of the parsed packet 1372 * into this memory location; zero on error. 1373 * @max_packet_size: maximum number of bytes to parse 1374 * 1375 * Returns zero on success; non-zero on error. 1376 */ 1377 static int 1378 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1379 unsigned char *data, struct list_head *auth_tok_list, 1380 struct ecryptfs_auth_tok **new_auth_tok, 1381 size_t *packet_size, size_t max_packet_size) 1382 { 1383 size_t body_size; 1384 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1385 size_t length_size; 1386 int rc = 0; 1387 1388 (*packet_size) = 0; 1389 (*new_auth_tok) = NULL; 1390 /** 1391 *This format is inspired by OpenPGP; see RFC 2440 1392 * packet tag 3 1393 * 1394 * Tag 3 identifier (1 byte) 1395 * Max Tag 3 packet size (max 3 bytes) 1396 * Version (1 byte) 1397 * Cipher code (1 byte) 1398 * S2K specifier (1 byte) 1399 * Hash identifier (1 byte) 1400 * Salt (ECRYPTFS_SALT_SIZE) 1401 * Hash iterations (1 byte) 1402 * Encrypted key (arbitrary) 1403 * 1404 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1405 */ 1406 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1407 printk(KERN_ERR "Max packet size too large\n"); 1408 rc = -EINVAL; 1409 goto out; 1410 } 1411 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1412 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1413 ECRYPTFS_TAG_3_PACKET_TYPE); 1414 rc = -EINVAL; 1415 goto out; 1416 } 1417 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1418 * at end of function upon failure */ 1419 auth_tok_list_item = 1420 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1421 if (!auth_tok_list_item) { 1422 printk(KERN_ERR "Unable to allocate memory\n"); 1423 rc = -ENOMEM; 1424 goto out; 1425 } 1426 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1427 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1428 &length_size); 1429 if (rc) { 1430 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1431 rc); 1432 goto out_free; 1433 } 1434 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1435 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1436 rc = -EINVAL; 1437 goto out_free; 1438 } 1439 (*packet_size) += length_size; 1440 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1441 printk(KERN_ERR "Packet size exceeds max\n"); 1442 rc = -EINVAL; 1443 goto out_free; 1444 } 1445 (*new_auth_tok)->session_key.encrypted_key_size = 1446 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1447 if ((*new_auth_tok)->session_key.encrypted_key_size 1448 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1449 printk(KERN_WARNING "Tag 3 packet contains key larger " 1450 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1451 rc = -EINVAL; 1452 goto out_free; 1453 } 1454 if (unlikely(data[(*packet_size)++] != 0x04)) { 1455 printk(KERN_WARNING "Unknown version number [%d]\n", 1456 data[(*packet_size) - 1]); 1457 rc = -EINVAL; 1458 goto out_free; 1459 } 1460 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1461 (u16)data[(*packet_size)]); 1462 if (rc) 1463 goto out_free; 1464 /* A little extra work to differentiate among the AES key 1465 * sizes; see RFC2440 */ 1466 switch(data[(*packet_size)++]) { 1467 case RFC2440_CIPHER_AES_192: 1468 crypt_stat->key_size = 24; 1469 break; 1470 default: 1471 crypt_stat->key_size = 1472 (*new_auth_tok)->session_key.encrypted_key_size; 1473 } 1474 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1475 if (rc) 1476 goto out_free; 1477 if (unlikely(data[(*packet_size)++] != 0x03)) { 1478 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1479 rc = -ENOSYS; 1480 goto out_free; 1481 } 1482 /* TODO: finish the hash mapping */ 1483 switch (data[(*packet_size)++]) { 1484 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1485 /* Choose MD5 */ 1486 memcpy((*new_auth_tok)->token.password.salt, 1487 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1488 (*packet_size) += ECRYPTFS_SALT_SIZE; 1489 /* This conversion was taken straight from RFC2440 */ 1490 (*new_auth_tok)->token.password.hash_iterations = 1491 ((u32) 16 + (data[(*packet_size)] & 15)) 1492 << ((data[(*packet_size)] >> 4) + 6); 1493 (*packet_size)++; 1494 /* Friendly reminder: 1495 * (*new_auth_tok)->session_key.encrypted_key_size = 1496 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1497 memcpy((*new_auth_tok)->session_key.encrypted_key, 1498 &data[(*packet_size)], 1499 (*new_auth_tok)->session_key.encrypted_key_size); 1500 (*packet_size) += 1501 (*new_auth_tok)->session_key.encrypted_key_size; 1502 (*new_auth_tok)->session_key.flags &= 1503 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1504 (*new_auth_tok)->session_key.flags |= 1505 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1506 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1507 break; 1508 default: 1509 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1510 "[%d]\n", data[(*packet_size) - 1]); 1511 rc = -ENOSYS; 1512 goto out_free; 1513 } 1514 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1515 /* TODO: Parametarize; we might actually want userspace to 1516 * decrypt the session key. */ 1517 (*new_auth_tok)->session_key.flags &= 1518 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1519 (*new_auth_tok)->session_key.flags &= 1520 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1521 list_add(&auth_tok_list_item->list, auth_tok_list); 1522 goto out; 1523 out_free: 1524 (*new_auth_tok) = NULL; 1525 memset(auth_tok_list_item, 0, 1526 sizeof(struct ecryptfs_auth_tok_list_item)); 1527 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1528 auth_tok_list_item); 1529 out: 1530 if (rc) 1531 (*packet_size) = 0; 1532 return rc; 1533 } 1534 1535 /** 1536 * parse_tag_11_packet 1537 * @data: The raw bytes of the packet 1538 * @contents: This function writes the data contents of the literal 1539 * packet into this memory location 1540 * @max_contents_bytes: The maximum number of bytes that this function 1541 * is allowed to write into contents 1542 * @tag_11_contents_size: This function writes the size of the parsed 1543 * contents into this memory location; zero on 1544 * error 1545 * @packet_size: This function writes the size of the parsed packet 1546 * into this memory location; zero on error 1547 * @max_packet_size: maximum number of bytes to parse 1548 * 1549 * Returns zero on success; non-zero on error. 1550 */ 1551 static int 1552 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1553 size_t max_contents_bytes, size_t *tag_11_contents_size, 1554 size_t *packet_size, size_t max_packet_size) 1555 { 1556 size_t body_size; 1557 size_t length_size; 1558 int rc = 0; 1559 1560 (*packet_size) = 0; 1561 (*tag_11_contents_size) = 0; 1562 /* This format is inspired by OpenPGP; see RFC 2440 1563 * packet tag 11 1564 * 1565 * Tag 11 identifier (1 byte) 1566 * Max Tag 11 packet size (max 3 bytes) 1567 * Binary format specifier (1 byte) 1568 * Filename length (1 byte) 1569 * Filename ("_CONSOLE") (8 bytes) 1570 * Modification date (4 bytes) 1571 * Literal data (arbitrary) 1572 * 1573 * We need at least 16 bytes of data for the packet to even be 1574 * valid. 1575 */ 1576 if (max_packet_size < 16) { 1577 printk(KERN_ERR "Maximum packet size too small\n"); 1578 rc = -EINVAL; 1579 goto out; 1580 } 1581 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1582 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1583 rc = -EINVAL; 1584 goto out; 1585 } 1586 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1587 &length_size); 1588 if (rc) { 1589 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1590 goto out; 1591 } 1592 if (body_size < 14) { 1593 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1594 rc = -EINVAL; 1595 goto out; 1596 } 1597 (*packet_size) += length_size; 1598 (*tag_11_contents_size) = (body_size - 14); 1599 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1600 printk(KERN_ERR "Packet size exceeds max\n"); 1601 rc = -EINVAL; 1602 goto out; 1603 } 1604 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1605 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1606 "expected size\n"); 1607 rc = -EINVAL; 1608 goto out; 1609 } 1610 if (data[(*packet_size)++] != 0x62) { 1611 printk(KERN_WARNING "Unrecognizable packet\n"); 1612 rc = -EINVAL; 1613 goto out; 1614 } 1615 if (data[(*packet_size)++] != 0x08) { 1616 printk(KERN_WARNING "Unrecognizable packet\n"); 1617 rc = -EINVAL; 1618 goto out; 1619 } 1620 (*packet_size) += 12; /* Ignore filename and modification date */ 1621 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1622 (*packet_size) += (*tag_11_contents_size); 1623 out: 1624 if (rc) { 1625 (*packet_size) = 0; 1626 (*tag_11_contents_size) = 0; 1627 } 1628 return rc; 1629 } 1630 1631 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1632 struct ecryptfs_auth_tok **auth_tok, 1633 char *sig) 1634 { 1635 int rc = 0; 1636 1637 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1638 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1639 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1640 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1641 printk(KERN_ERR "Could not find key with description: [%s]\n", 1642 sig); 1643 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1644 (*auth_tok_key) = NULL; 1645 goto out; 1646 } 1647 } 1648 down_write(&(*auth_tok_key)->sem); 1649 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1650 if (rc) { 1651 up_write(&(*auth_tok_key)->sem); 1652 key_put(*auth_tok_key); 1653 (*auth_tok_key) = NULL; 1654 goto out; 1655 } 1656 out: 1657 return rc; 1658 } 1659 1660 /** 1661 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1662 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1663 * @crypt_stat: The cryptographic context 1664 * 1665 * Returns zero on success; non-zero error otherwise 1666 */ 1667 static int 1668 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1669 struct ecryptfs_crypt_stat *crypt_stat) 1670 { 1671 struct scatterlist dst_sg[2]; 1672 struct scatterlist src_sg[2]; 1673 struct mutex *tfm_mutex; 1674 struct blkcipher_desc desc = { 1675 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 1676 }; 1677 int rc = 0; 1678 1679 if (unlikely(ecryptfs_verbosity > 0)) { 1680 ecryptfs_printk( 1681 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1682 auth_tok->token.password.session_key_encryption_key_bytes); 1683 ecryptfs_dump_hex( 1684 auth_tok->token.password.session_key_encryption_key, 1685 auth_tok->token.password.session_key_encryption_key_bytes); 1686 } 1687 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 1688 crypt_stat->cipher); 1689 if (unlikely(rc)) { 1690 printk(KERN_ERR "Internal error whilst attempting to get " 1691 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1692 crypt_stat->cipher, rc); 1693 goto out; 1694 } 1695 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1696 auth_tok->session_key.encrypted_key_size, 1697 src_sg, 2); 1698 if (rc < 1 || rc > 2) { 1699 printk(KERN_ERR "Internal error whilst attempting to convert " 1700 "auth_tok->session_key.encrypted_key to scatterlist; " 1701 "expected rc = 1; got rc = [%d]. " 1702 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1703 auth_tok->session_key.encrypted_key_size); 1704 goto out; 1705 } 1706 auth_tok->session_key.decrypted_key_size = 1707 auth_tok->session_key.encrypted_key_size; 1708 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1709 auth_tok->session_key.decrypted_key_size, 1710 dst_sg, 2); 1711 if (rc < 1 || rc > 2) { 1712 printk(KERN_ERR "Internal error whilst attempting to convert " 1713 "auth_tok->session_key.decrypted_key to scatterlist; " 1714 "expected rc = 1; got rc = [%d]\n", rc); 1715 goto out; 1716 } 1717 mutex_lock(tfm_mutex); 1718 rc = crypto_blkcipher_setkey( 1719 desc.tfm, auth_tok->token.password.session_key_encryption_key, 1720 crypt_stat->key_size); 1721 if (unlikely(rc < 0)) { 1722 mutex_unlock(tfm_mutex); 1723 printk(KERN_ERR "Error setting key for crypto context\n"); 1724 rc = -EINVAL; 1725 goto out; 1726 } 1727 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg, 1728 auth_tok->session_key.encrypted_key_size); 1729 mutex_unlock(tfm_mutex); 1730 if (unlikely(rc)) { 1731 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1732 goto out; 1733 } 1734 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1735 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1736 auth_tok->session_key.decrypted_key_size); 1737 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1738 if (unlikely(ecryptfs_verbosity > 0)) { 1739 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1740 crypt_stat->key_size); 1741 ecryptfs_dump_hex(crypt_stat->key, 1742 crypt_stat->key_size); 1743 } 1744 out: 1745 return rc; 1746 } 1747 1748 /** 1749 * ecryptfs_parse_packet_set 1750 * @crypt_stat: The cryptographic context 1751 * @src: Virtual address of region of memory containing the packets 1752 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1753 * 1754 * Get crypt_stat to have the file's session key if the requisite key 1755 * is available to decrypt the session key. 1756 * 1757 * Returns Zero if a valid authentication token was retrieved and 1758 * processed; negative value for file not encrypted or for error 1759 * conditions. 1760 */ 1761 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1762 unsigned char *src, 1763 struct dentry *ecryptfs_dentry) 1764 { 1765 size_t i = 0; 1766 size_t found_auth_tok; 1767 size_t next_packet_is_auth_tok_packet; 1768 struct list_head auth_tok_list; 1769 struct ecryptfs_auth_tok *matching_auth_tok; 1770 struct ecryptfs_auth_tok *candidate_auth_tok; 1771 char *candidate_auth_tok_sig; 1772 size_t packet_size; 1773 struct ecryptfs_auth_tok *new_auth_tok; 1774 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1775 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1776 size_t tag_11_contents_size; 1777 size_t tag_11_packet_size; 1778 struct key *auth_tok_key = NULL; 1779 int rc = 0; 1780 1781 INIT_LIST_HEAD(&auth_tok_list); 1782 /* Parse the header to find as many packets as we can; these will be 1783 * added the our &auth_tok_list */ 1784 next_packet_is_auth_tok_packet = 1; 1785 while (next_packet_is_auth_tok_packet) { 1786 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i); 1787 1788 switch (src[i]) { 1789 case ECRYPTFS_TAG_3_PACKET_TYPE: 1790 rc = parse_tag_3_packet(crypt_stat, 1791 (unsigned char *)&src[i], 1792 &auth_tok_list, &new_auth_tok, 1793 &packet_size, max_packet_size); 1794 if (rc) { 1795 ecryptfs_printk(KERN_ERR, "Error parsing " 1796 "tag 3 packet\n"); 1797 rc = -EIO; 1798 goto out_wipe_list; 1799 } 1800 i += packet_size; 1801 rc = parse_tag_11_packet((unsigned char *)&src[i], 1802 sig_tmp_space, 1803 ECRYPTFS_SIG_SIZE, 1804 &tag_11_contents_size, 1805 &tag_11_packet_size, 1806 max_packet_size); 1807 if (rc) { 1808 ecryptfs_printk(KERN_ERR, "No valid " 1809 "(ecryptfs-specific) literal " 1810 "packet containing " 1811 "authentication token " 1812 "signature found after " 1813 "tag 3 packet\n"); 1814 rc = -EIO; 1815 goto out_wipe_list; 1816 } 1817 i += tag_11_packet_size; 1818 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1819 ecryptfs_printk(KERN_ERR, "Expected " 1820 "signature of size [%d]; " 1821 "read size [%zd]\n", 1822 ECRYPTFS_SIG_SIZE, 1823 tag_11_contents_size); 1824 rc = -EIO; 1825 goto out_wipe_list; 1826 } 1827 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1828 sig_tmp_space, tag_11_contents_size); 1829 new_auth_tok->token.password.signature[ 1830 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1831 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1832 break; 1833 case ECRYPTFS_TAG_1_PACKET_TYPE: 1834 rc = parse_tag_1_packet(crypt_stat, 1835 (unsigned char *)&src[i], 1836 &auth_tok_list, &new_auth_tok, 1837 &packet_size, max_packet_size); 1838 if (rc) { 1839 ecryptfs_printk(KERN_ERR, "Error parsing " 1840 "tag 1 packet\n"); 1841 rc = -EIO; 1842 goto out_wipe_list; 1843 } 1844 i += packet_size; 1845 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1846 break; 1847 case ECRYPTFS_TAG_11_PACKET_TYPE: 1848 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1849 "(Tag 11 not allowed by itself)\n"); 1850 rc = -EIO; 1851 goto out_wipe_list; 1852 break; 1853 default: 1854 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1855 "of the file header; hex value of " 1856 "character is [0x%.2x]\n", i, src[i]); 1857 next_packet_is_auth_tok_packet = 0; 1858 } 1859 } 1860 if (list_empty(&auth_tok_list)) { 1861 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1862 "eCryptfs file; this is not supported in this version " 1863 "of the eCryptfs kernel module\n"); 1864 rc = -EINVAL; 1865 goto out; 1866 } 1867 /* auth_tok_list contains the set of authentication tokens 1868 * parsed from the metadata. We need to find a matching 1869 * authentication token that has the secret component(s) 1870 * necessary to decrypt the EFEK in the auth_tok parsed from 1871 * the metadata. There may be several potential matches, but 1872 * just one will be sufficient to decrypt to get the FEK. */ 1873 find_next_matching_auth_tok: 1874 found_auth_tok = 0; 1875 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1876 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1877 if (unlikely(ecryptfs_verbosity > 0)) { 1878 ecryptfs_printk(KERN_DEBUG, 1879 "Considering cadidate auth tok:\n"); 1880 ecryptfs_dump_auth_tok(candidate_auth_tok); 1881 } 1882 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1883 candidate_auth_tok); 1884 if (rc) { 1885 printk(KERN_ERR 1886 "Unrecognized candidate auth tok type: [%d]\n", 1887 candidate_auth_tok->token_type); 1888 rc = -EINVAL; 1889 goto out_wipe_list; 1890 } 1891 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1892 &matching_auth_tok, 1893 crypt_stat->mount_crypt_stat, 1894 candidate_auth_tok_sig); 1895 if (!rc) { 1896 found_auth_tok = 1; 1897 goto found_matching_auth_tok; 1898 } 1899 } 1900 if (!found_auth_tok) { 1901 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1902 "authentication token\n"); 1903 rc = -EIO; 1904 goto out_wipe_list; 1905 } 1906 found_matching_auth_tok: 1907 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1908 memcpy(&(candidate_auth_tok->token.private_key), 1909 &(matching_auth_tok->token.private_key), 1910 sizeof(struct ecryptfs_private_key)); 1911 up_write(&(auth_tok_key->sem)); 1912 key_put(auth_tok_key); 1913 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1914 crypt_stat); 1915 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1916 memcpy(&(candidate_auth_tok->token.password), 1917 &(matching_auth_tok->token.password), 1918 sizeof(struct ecryptfs_password)); 1919 up_write(&(auth_tok_key->sem)); 1920 key_put(auth_tok_key); 1921 rc = decrypt_passphrase_encrypted_session_key( 1922 candidate_auth_tok, crypt_stat); 1923 } else { 1924 up_write(&(auth_tok_key->sem)); 1925 key_put(auth_tok_key); 1926 rc = -EINVAL; 1927 } 1928 if (rc) { 1929 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1930 1931 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1932 "session key for authentication token with sig " 1933 "[%.*s]; rc = [%d]. Removing auth tok " 1934 "candidate from the list and searching for " 1935 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1936 candidate_auth_tok_sig, rc); 1937 list_for_each_entry_safe(auth_tok_list_item, 1938 auth_tok_list_item_tmp, 1939 &auth_tok_list, list) { 1940 if (candidate_auth_tok 1941 == &auth_tok_list_item->auth_tok) { 1942 list_del(&auth_tok_list_item->list); 1943 kmem_cache_free( 1944 ecryptfs_auth_tok_list_item_cache, 1945 auth_tok_list_item); 1946 goto find_next_matching_auth_tok; 1947 } 1948 } 1949 BUG(); 1950 } 1951 rc = ecryptfs_compute_root_iv(crypt_stat); 1952 if (rc) { 1953 ecryptfs_printk(KERN_ERR, "Error computing " 1954 "the root IV\n"); 1955 goto out_wipe_list; 1956 } 1957 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1958 if (rc) { 1959 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1960 "context for cipher [%s]; rc = [%d]\n", 1961 crypt_stat->cipher, rc); 1962 } 1963 out_wipe_list: 1964 wipe_auth_tok_list(&auth_tok_list); 1965 out: 1966 return rc; 1967 } 1968 1969 static int 1970 pki_encrypt_session_key(struct key *auth_tok_key, 1971 struct ecryptfs_auth_tok *auth_tok, 1972 struct ecryptfs_crypt_stat *crypt_stat, 1973 struct ecryptfs_key_record *key_rec) 1974 { 1975 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1976 char *payload = NULL; 1977 size_t payload_len = 0; 1978 struct ecryptfs_message *msg; 1979 int rc; 1980 1981 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1982 ecryptfs_code_for_cipher_string( 1983 crypt_stat->cipher, 1984 crypt_stat->key_size), 1985 crypt_stat, &payload, &payload_len); 1986 up_write(&(auth_tok_key->sem)); 1987 key_put(auth_tok_key); 1988 if (rc) { 1989 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1990 goto out; 1991 } 1992 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1993 if (rc) { 1994 ecryptfs_printk(KERN_ERR, "Error sending message to " 1995 "ecryptfsd\n"); 1996 goto out; 1997 } 1998 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1999 if (rc) { 2000 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 2001 "from the user space daemon\n"); 2002 rc = -EIO; 2003 goto out; 2004 } 2005 rc = parse_tag_67_packet(key_rec, msg); 2006 if (rc) 2007 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2008 kfree(msg); 2009 out: 2010 kfree(payload); 2011 return rc; 2012 } 2013 /** 2014 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2015 * @dest: Buffer into which to write the packet 2016 * @remaining_bytes: Maximum number of bytes that can be writtn 2017 * @auth_tok_key: The authentication token key to unlock and put when done with 2018 * @auth_tok 2019 * @auth_tok: The authentication token used for generating the tag 1 packet 2020 * @crypt_stat: The cryptographic context 2021 * @key_rec: The key record struct for the tag 1 packet 2022 * @packet_size: This function will write the number of bytes that end 2023 * up constituting the packet; set to zero on error 2024 * 2025 * Returns zero on success; non-zero on error. 2026 */ 2027 static int 2028 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2029 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2030 struct ecryptfs_crypt_stat *crypt_stat, 2031 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2032 { 2033 size_t i; 2034 size_t encrypted_session_key_valid = 0; 2035 size_t packet_size_length; 2036 size_t max_packet_size; 2037 int rc = 0; 2038 2039 (*packet_size) = 0; 2040 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2041 ECRYPTFS_SIG_SIZE); 2042 encrypted_session_key_valid = 0; 2043 for (i = 0; i < crypt_stat->key_size; i++) 2044 encrypted_session_key_valid |= 2045 auth_tok->session_key.encrypted_key[i]; 2046 if (encrypted_session_key_valid) { 2047 memcpy(key_rec->enc_key, 2048 auth_tok->session_key.encrypted_key, 2049 auth_tok->session_key.encrypted_key_size); 2050 up_write(&(auth_tok_key->sem)); 2051 key_put(auth_tok_key); 2052 goto encrypted_session_key_set; 2053 } 2054 if (auth_tok->session_key.encrypted_key_size == 0) 2055 auth_tok->session_key.encrypted_key_size = 2056 auth_tok->token.private_key.key_size; 2057 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2058 key_rec); 2059 if (rc) { 2060 printk(KERN_ERR "Failed to encrypt session key via a key " 2061 "module; rc = [%d]\n", rc); 2062 goto out; 2063 } 2064 if (ecryptfs_verbosity > 0) { 2065 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2066 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2067 } 2068 encrypted_session_key_set: 2069 /* This format is inspired by OpenPGP; see RFC 2440 2070 * packet tag 1 */ 2071 max_packet_size = (1 /* Tag 1 identifier */ 2072 + 3 /* Max Tag 1 packet size */ 2073 + 1 /* Version */ 2074 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2075 + 1 /* Cipher identifier */ 2076 + key_rec->enc_key_size); /* Encrypted key size */ 2077 if (max_packet_size > (*remaining_bytes)) { 2078 printk(KERN_ERR "Packet length larger than maximum allowable; " 2079 "need up to [%td] bytes, but there are only [%td] " 2080 "available\n", max_packet_size, (*remaining_bytes)); 2081 rc = -EINVAL; 2082 goto out; 2083 } 2084 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2085 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2086 (max_packet_size - 4), 2087 &packet_size_length); 2088 if (rc) { 2089 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2090 "header; cannot generate packet length\n"); 2091 goto out; 2092 } 2093 (*packet_size) += packet_size_length; 2094 dest[(*packet_size)++] = 0x03; /* version 3 */ 2095 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2096 (*packet_size) += ECRYPTFS_SIG_SIZE; 2097 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2098 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2099 key_rec->enc_key_size); 2100 (*packet_size) += key_rec->enc_key_size; 2101 out: 2102 if (rc) 2103 (*packet_size) = 0; 2104 else 2105 (*remaining_bytes) -= (*packet_size); 2106 return rc; 2107 } 2108 2109 /** 2110 * write_tag_11_packet 2111 * @dest: Target into which Tag 11 packet is to be written 2112 * @remaining_bytes: Maximum packet length 2113 * @contents: Byte array of contents to copy in 2114 * @contents_length: Number of bytes in contents 2115 * @packet_length: Length of the Tag 11 packet written; zero on error 2116 * 2117 * Returns zero on success; non-zero on error. 2118 */ 2119 static int 2120 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2121 size_t contents_length, size_t *packet_length) 2122 { 2123 size_t packet_size_length; 2124 size_t max_packet_size; 2125 int rc = 0; 2126 2127 (*packet_length) = 0; 2128 /* This format is inspired by OpenPGP; see RFC 2440 2129 * packet tag 11 */ 2130 max_packet_size = (1 /* Tag 11 identifier */ 2131 + 3 /* Max Tag 11 packet size */ 2132 + 1 /* Binary format specifier */ 2133 + 1 /* Filename length */ 2134 + 8 /* Filename ("_CONSOLE") */ 2135 + 4 /* Modification date */ 2136 + contents_length); /* Literal data */ 2137 if (max_packet_size > (*remaining_bytes)) { 2138 printk(KERN_ERR "Packet length larger than maximum allowable; " 2139 "need up to [%td] bytes, but there are only [%td] " 2140 "available\n", max_packet_size, (*remaining_bytes)); 2141 rc = -EINVAL; 2142 goto out; 2143 } 2144 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2145 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2146 (max_packet_size - 4), 2147 &packet_size_length); 2148 if (rc) { 2149 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2150 "generate packet length. rc = [%d]\n", rc); 2151 goto out; 2152 } 2153 (*packet_length) += packet_size_length; 2154 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2155 dest[(*packet_length)++] = 8; 2156 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2157 (*packet_length) += 8; 2158 memset(&dest[(*packet_length)], 0x00, 4); 2159 (*packet_length) += 4; 2160 memcpy(&dest[(*packet_length)], contents, contents_length); 2161 (*packet_length) += contents_length; 2162 out: 2163 if (rc) 2164 (*packet_length) = 0; 2165 else 2166 (*remaining_bytes) -= (*packet_length); 2167 return rc; 2168 } 2169 2170 /** 2171 * write_tag_3_packet 2172 * @dest: Buffer into which to write the packet 2173 * @remaining_bytes: Maximum number of bytes that can be written 2174 * @auth_tok: Authentication token 2175 * @crypt_stat: The cryptographic context 2176 * @key_rec: encrypted key 2177 * @packet_size: This function will write the number of bytes that end 2178 * up constituting the packet; set to zero on error 2179 * 2180 * Returns zero on success; non-zero on error. 2181 */ 2182 static int 2183 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2184 struct ecryptfs_auth_tok *auth_tok, 2185 struct ecryptfs_crypt_stat *crypt_stat, 2186 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2187 { 2188 size_t i; 2189 size_t encrypted_session_key_valid = 0; 2190 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2191 struct scatterlist dst_sg[2]; 2192 struct scatterlist src_sg[2]; 2193 struct mutex *tfm_mutex = NULL; 2194 u8 cipher_code; 2195 size_t packet_size_length; 2196 size_t max_packet_size; 2197 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2198 crypt_stat->mount_crypt_stat; 2199 struct blkcipher_desc desc = { 2200 .tfm = NULL, 2201 .flags = CRYPTO_TFM_REQ_MAY_SLEEP 2202 }; 2203 int rc = 0; 2204 2205 (*packet_size) = 0; 2206 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2207 ECRYPTFS_SIG_SIZE); 2208 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, 2209 crypt_stat->cipher); 2210 if (unlikely(rc)) { 2211 printk(KERN_ERR "Internal error whilst attempting to get " 2212 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2213 crypt_stat->cipher, rc); 2214 goto out; 2215 } 2216 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2217 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm); 2218 2219 printk(KERN_WARNING "No key size specified at mount; " 2220 "defaulting to [%d]\n", alg->max_keysize); 2221 mount_crypt_stat->global_default_cipher_key_size = 2222 alg->max_keysize; 2223 } 2224 if (crypt_stat->key_size == 0) 2225 crypt_stat->key_size = 2226 mount_crypt_stat->global_default_cipher_key_size; 2227 if (auth_tok->session_key.encrypted_key_size == 0) 2228 auth_tok->session_key.encrypted_key_size = 2229 crypt_stat->key_size; 2230 if (crypt_stat->key_size == 24 2231 && strcmp("aes", crypt_stat->cipher) == 0) { 2232 memset((crypt_stat->key + 24), 0, 8); 2233 auth_tok->session_key.encrypted_key_size = 32; 2234 } else 2235 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2236 key_rec->enc_key_size = 2237 auth_tok->session_key.encrypted_key_size; 2238 encrypted_session_key_valid = 0; 2239 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2240 encrypted_session_key_valid |= 2241 auth_tok->session_key.encrypted_key[i]; 2242 if (encrypted_session_key_valid) { 2243 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2244 "using auth_tok->session_key.encrypted_key, " 2245 "where key_rec->enc_key_size = [%zd]\n", 2246 key_rec->enc_key_size); 2247 memcpy(key_rec->enc_key, 2248 auth_tok->session_key.encrypted_key, 2249 key_rec->enc_key_size); 2250 goto encrypted_session_key_set; 2251 } 2252 if (auth_tok->token.password.flags & 2253 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2254 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2255 "session key encryption key of size [%d]\n", 2256 auth_tok->token.password. 2257 session_key_encryption_key_bytes); 2258 memcpy(session_key_encryption_key, 2259 auth_tok->token.password.session_key_encryption_key, 2260 crypt_stat->key_size); 2261 ecryptfs_printk(KERN_DEBUG, 2262 "Cached session key encryption key:\n"); 2263 if (ecryptfs_verbosity > 0) 2264 ecryptfs_dump_hex(session_key_encryption_key, 16); 2265 } 2266 if (unlikely(ecryptfs_verbosity > 0)) { 2267 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2268 ecryptfs_dump_hex(session_key_encryption_key, 16); 2269 } 2270 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2271 src_sg, 2); 2272 if (rc < 1 || rc > 2) { 2273 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2274 "for crypt_stat session key; expected rc = 1; " 2275 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2276 rc, key_rec->enc_key_size); 2277 rc = -ENOMEM; 2278 goto out; 2279 } 2280 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2281 dst_sg, 2); 2282 if (rc < 1 || rc > 2) { 2283 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2284 "for crypt_stat encrypted session key; " 2285 "expected rc = 1; got rc = [%d]. " 2286 "key_rec->enc_key_size = [%zd]\n", rc, 2287 key_rec->enc_key_size); 2288 rc = -ENOMEM; 2289 goto out; 2290 } 2291 mutex_lock(tfm_mutex); 2292 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key, 2293 crypt_stat->key_size); 2294 if (rc < 0) { 2295 mutex_unlock(tfm_mutex); 2296 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2297 "context; rc = [%d]\n", rc); 2298 goto out; 2299 } 2300 rc = 0; 2301 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2302 crypt_stat->key_size); 2303 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg, 2304 (*key_rec).enc_key_size); 2305 mutex_unlock(tfm_mutex); 2306 if (rc) { 2307 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2308 goto out; 2309 } 2310 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2311 if (ecryptfs_verbosity > 0) { 2312 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2313 key_rec->enc_key_size); 2314 ecryptfs_dump_hex(key_rec->enc_key, 2315 key_rec->enc_key_size); 2316 } 2317 encrypted_session_key_set: 2318 /* This format is inspired by OpenPGP; see RFC 2440 2319 * packet tag 3 */ 2320 max_packet_size = (1 /* Tag 3 identifier */ 2321 + 3 /* Max Tag 3 packet size */ 2322 + 1 /* Version */ 2323 + 1 /* Cipher code */ 2324 + 1 /* S2K specifier */ 2325 + 1 /* Hash identifier */ 2326 + ECRYPTFS_SALT_SIZE /* Salt */ 2327 + 1 /* Hash iterations */ 2328 + key_rec->enc_key_size); /* Encrypted key size */ 2329 if (max_packet_size > (*remaining_bytes)) { 2330 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2331 "there are only [%td] available\n", max_packet_size, 2332 (*remaining_bytes)); 2333 rc = -EINVAL; 2334 goto out; 2335 } 2336 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2337 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2338 * to get the number of octets in the actual Tag 3 packet */ 2339 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2340 (max_packet_size - 4), 2341 &packet_size_length); 2342 if (rc) { 2343 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2344 "generate packet length. rc = [%d]\n", rc); 2345 goto out; 2346 } 2347 (*packet_size) += packet_size_length; 2348 dest[(*packet_size)++] = 0x04; /* version 4 */ 2349 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2350 * specified with strings */ 2351 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2352 crypt_stat->key_size); 2353 if (cipher_code == 0) { 2354 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2355 "cipher [%s]\n", crypt_stat->cipher); 2356 rc = -EINVAL; 2357 goto out; 2358 } 2359 dest[(*packet_size)++] = cipher_code; 2360 dest[(*packet_size)++] = 0x03; /* S2K */ 2361 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2362 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2363 ECRYPTFS_SALT_SIZE); 2364 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2365 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2366 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2367 key_rec->enc_key_size); 2368 (*packet_size) += key_rec->enc_key_size; 2369 out: 2370 if (rc) 2371 (*packet_size) = 0; 2372 else 2373 (*remaining_bytes) -= (*packet_size); 2374 return rc; 2375 } 2376 2377 struct kmem_cache *ecryptfs_key_record_cache; 2378 2379 /** 2380 * ecryptfs_generate_key_packet_set 2381 * @dest_base: Virtual address from which to write the key record set 2382 * @crypt_stat: The cryptographic context from which the 2383 * authentication tokens will be retrieved 2384 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2385 * for the global parameters 2386 * @len: The amount written 2387 * @max: The maximum amount of data allowed to be written 2388 * 2389 * Generates a key packet set and writes it to the virtual address 2390 * passed in. 2391 * 2392 * Returns zero on success; non-zero on error. 2393 */ 2394 int 2395 ecryptfs_generate_key_packet_set(char *dest_base, 2396 struct ecryptfs_crypt_stat *crypt_stat, 2397 struct dentry *ecryptfs_dentry, size_t *len, 2398 size_t max) 2399 { 2400 struct ecryptfs_auth_tok *auth_tok; 2401 struct key *auth_tok_key = NULL; 2402 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2403 &ecryptfs_superblock_to_private( 2404 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2405 size_t written; 2406 struct ecryptfs_key_record *key_rec; 2407 struct ecryptfs_key_sig *key_sig; 2408 int rc = 0; 2409 2410 (*len) = 0; 2411 mutex_lock(&crypt_stat->keysig_list_mutex); 2412 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2413 if (!key_rec) { 2414 rc = -ENOMEM; 2415 goto out; 2416 } 2417 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2418 crypt_stat_list) { 2419 memset(key_rec, 0, sizeof(*key_rec)); 2420 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2421 &auth_tok, 2422 mount_crypt_stat, 2423 key_sig->keysig); 2424 if (rc) { 2425 printk(KERN_WARNING "Unable to retrieve auth tok with " 2426 "sig = [%s]\n", key_sig->keysig); 2427 rc = process_find_global_auth_tok_for_sig_err(rc); 2428 goto out_free; 2429 } 2430 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2431 rc = write_tag_3_packet((dest_base + (*len)), 2432 &max, auth_tok, 2433 crypt_stat, key_rec, 2434 &written); 2435 up_write(&(auth_tok_key->sem)); 2436 key_put(auth_tok_key); 2437 if (rc) { 2438 ecryptfs_printk(KERN_WARNING, "Error " 2439 "writing tag 3 packet\n"); 2440 goto out_free; 2441 } 2442 (*len) += written; 2443 /* Write auth tok signature packet */ 2444 rc = write_tag_11_packet((dest_base + (*len)), &max, 2445 key_rec->sig, 2446 ECRYPTFS_SIG_SIZE, &written); 2447 if (rc) { 2448 ecryptfs_printk(KERN_ERR, "Error writing " 2449 "auth tok signature packet\n"); 2450 goto out_free; 2451 } 2452 (*len) += written; 2453 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2454 rc = write_tag_1_packet(dest_base + (*len), &max, 2455 auth_tok_key, auth_tok, 2456 crypt_stat, key_rec, &written); 2457 if (rc) { 2458 ecryptfs_printk(KERN_WARNING, "Error " 2459 "writing tag 1 packet\n"); 2460 goto out_free; 2461 } 2462 (*len) += written; 2463 } else { 2464 up_write(&(auth_tok_key->sem)); 2465 key_put(auth_tok_key); 2466 ecryptfs_printk(KERN_WARNING, "Unsupported " 2467 "authentication token type\n"); 2468 rc = -EINVAL; 2469 goto out_free; 2470 } 2471 } 2472 if (likely(max > 0)) { 2473 dest_base[(*len)] = 0x00; 2474 } else { 2475 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2476 rc = -EIO; 2477 } 2478 out_free: 2479 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2480 out: 2481 if (rc) 2482 (*len) = 0; 2483 mutex_unlock(&crypt_stat->keysig_list_mutex); 2484 return rc; 2485 } 2486 2487 struct kmem_cache *ecryptfs_key_sig_cache; 2488 2489 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2490 { 2491 struct ecryptfs_key_sig *new_key_sig; 2492 2493 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2494 if (!new_key_sig) { 2495 printk(KERN_ERR 2496 "Error allocating from ecryptfs_key_sig_cache\n"); 2497 return -ENOMEM; 2498 } 2499 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2500 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2501 /* Caller must hold keysig_list_mutex */ 2502 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2503 2504 return 0; 2505 } 2506 2507 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2508 2509 int 2510 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2511 char *sig, u32 global_auth_tok_flags) 2512 { 2513 struct ecryptfs_global_auth_tok *new_auth_tok; 2514 int rc = 0; 2515 2516 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2517 GFP_KERNEL); 2518 if (!new_auth_tok) { 2519 rc = -ENOMEM; 2520 printk(KERN_ERR "Error allocating from " 2521 "ecryptfs_global_auth_tok_cache\n"); 2522 goto out; 2523 } 2524 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2525 new_auth_tok->flags = global_auth_tok_flags; 2526 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2527 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2528 list_add(&new_auth_tok->mount_crypt_stat_list, 2529 &mount_crypt_stat->global_auth_tok_list); 2530 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2531 out: 2532 return rc; 2533 } 2534 2535