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 <crypto/hash.h> 29 #include <crypto/skcipher.h> 30 #include <linux/string.h> 31 #include <linux/pagemap.h> 32 #include <linux/key.h> 33 #include <linux/random.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) = data[0]; 105 (*length_size) = 1; 106 } else if (data[0] < 224) { 107 /* Two-byte length */ 108 (*size) = (data[0] - 192) * 256; 109 (*size) += 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 crypto_skcipher *skcipher_tfm; 606 struct skcipher_request *skcipher_req; 607 char iv[ECRYPTFS_MAX_IV_BYTES]; 608 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 609 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 610 struct crypto_shash *hash_tfm; 611 struct shash_desc *hash_desc; 612 }; 613 614 /** 615 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK 616 * @filename: NULL-terminated filename string 617 * 618 * This is the simplest mechanism for achieving filename encryption in 619 * eCryptfs. It encrypts the given filename with the mount-wide 620 * filename encryption key (FNEK) and stores it in a packet to @dest, 621 * which the callee will encode and write directly into the dentry 622 * name. 623 */ 624 int 625 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, 626 size_t *packet_size, 627 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 628 char *filename, size_t filename_size) 629 { 630 struct ecryptfs_write_tag_70_packet_silly_stack *s; 631 struct key *auth_tok_key = NULL; 632 int rc = 0; 633 634 s = kzalloc(sizeof(*s), GFP_KERNEL); 635 if (!s) { 636 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 637 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 638 return -ENOMEM; 639 } 640 (*packet_size) = 0; 641 rc = ecryptfs_find_auth_tok_for_sig( 642 &auth_tok_key, 643 &s->auth_tok, mount_crypt_stat, 644 mount_crypt_stat->global_default_fnek_sig); 645 if (rc) { 646 printk(KERN_ERR "%s: Error attempting to find auth tok for " 647 "fnek sig [%s]; rc = [%d]\n", __func__, 648 mount_crypt_stat->global_default_fnek_sig, rc); 649 goto out; 650 } 651 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 652 &s->skcipher_tfm, 653 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 654 if (unlikely(rc)) { 655 printk(KERN_ERR "Internal error whilst attempting to get " 656 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 657 mount_crypt_stat->global_default_fn_cipher_name, rc); 658 goto out; 659 } 660 mutex_lock(s->tfm_mutex); 661 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm); 662 /* Plus one for the \0 separator between the random prefix 663 * and the plaintext filename */ 664 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 665 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 666 if ((s->block_aligned_filename_size % s->block_size) != 0) { 667 s->num_rand_bytes += (s->block_size 668 - (s->block_aligned_filename_size 669 % s->block_size)); 670 s->block_aligned_filename_size = (s->num_rand_bytes 671 + filename_size); 672 } 673 /* Octet 0: Tag 70 identifier 674 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 675 * and block-aligned encrypted filename size) 676 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 677 * Octet N2-N3: Cipher identifier (1 octet) 678 * Octets N3-N4: Block-aligned encrypted filename 679 * - Consists of a minimum number of random characters, a \0 680 * separator, and then the filename */ 681 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 682 + s->block_aligned_filename_size); 683 if (dest == NULL) { 684 (*packet_size) = s->max_packet_size; 685 goto out_unlock; 686 } 687 if (s->max_packet_size > (*remaining_bytes)) { 688 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 689 "[%zd] available\n", __func__, s->max_packet_size, 690 (*remaining_bytes)); 691 rc = -EINVAL; 692 goto out_unlock; 693 } 694 695 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 696 if (!s->skcipher_req) { 697 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 698 "skcipher_request_alloc for %s\n", __func__, 699 crypto_skcipher_driver_name(s->skcipher_tfm)); 700 rc = -ENOMEM; 701 goto out_unlock; 702 } 703 704 skcipher_request_set_callback(s->skcipher_req, 705 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 706 707 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 708 GFP_KERNEL); 709 if (!s->block_aligned_filename) { 710 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 711 "kzalloc [%zd] bytes\n", __func__, 712 s->block_aligned_filename_size); 713 rc = -ENOMEM; 714 goto out_unlock; 715 } 716 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 717 rc = ecryptfs_write_packet_length(&dest[s->i], 718 (ECRYPTFS_SIG_SIZE 719 + 1 /* Cipher code */ 720 + s->block_aligned_filename_size), 721 &s->packet_size_len); 722 if (rc) { 723 printk(KERN_ERR "%s: Error generating tag 70 packet " 724 "header; cannot generate packet length; rc = [%d]\n", 725 __func__, rc); 726 goto out_free_unlock; 727 } 728 s->i += s->packet_size_len; 729 ecryptfs_from_hex(&dest[s->i], 730 mount_crypt_stat->global_default_fnek_sig, 731 ECRYPTFS_SIG_SIZE); 732 s->i += ECRYPTFS_SIG_SIZE; 733 s->cipher_code = ecryptfs_code_for_cipher_string( 734 mount_crypt_stat->global_default_fn_cipher_name, 735 mount_crypt_stat->global_default_fn_cipher_key_bytes); 736 if (s->cipher_code == 0) { 737 printk(KERN_WARNING "%s: Unable to generate code for " 738 "cipher [%s] with key bytes [%zd]\n", __func__, 739 mount_crypt_stat->global_default_fn_cipher_name, 740 mount_crypt_stat->global_default_fn_cipher_key_bytes); 741 rc = -EINVAL; 742 goto out_free_unlock; 743 } 744 dest[s->i++] = s->cipher_code; 745 /* TODO: Support other key modules than passphrase for 746 * filename encryption */ 747 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 748 rc = -EOPNOTSUPP; 749 printk(KERN_INFO "%s: Filename encryption only supports " 750 "password tokens\n", __func__); 751 goto out_free_unlock; 752 } 753 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0); 754 if (IS_ERR(s->hash_tfm)) { 755 rc = PTR_ERR(s->hash_tfm); 756 printk(KERN_ERR "%s: Error attempting to " 757 "allocate hash crypto context; rc = [%d]\n", 758 __func__, rc); 759 goto out_free_unlock; 760 } 761 762 s->hash_desc = kmalloc(sizeof(*s->hash_desc) + 763 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL); 764 if (!s->hash_desc) { 765 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 766 "kmalloc [%zd] bytes\n", __func__, 767 sizeof(*s->hash_desc) + 768 crypto_shash_descsize(s->hash_tfm)); 769 rc = -ENOMEM; 770 goto out_release_free_unlock; 771 } 772 773 s->hash_desc->tfm = s->hash_tfm; 774 s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; 775 776 rc = crypto_shash_digest(s->hash_desc, 777 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 778 s->auth_tok->token.password.session_key_encryption_key_bytes, 779 s->hash); 780 if (rc) { 781 printk(KERN_ERR 782 "%s: Error computing crypto hash; rc = [%d]\n", 783 __func__, rc); 784 goto out_release_free_unlock; 785 } 786 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 787 s->block_aligned_filename[s->j] = 788 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 789 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 790 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 791 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash, 792 ECRYPTFS_TAG_70_DIGEST_SIZE, 793 s->tmp_hash); 794 if (rc) { 795 printk(KERN_ERR 796 "%s: Error computing crypto hash; " 797 "rc = [%d]\n", __func__, rc); 798 goto out_release_free_unlock; 799 } 800 memcpy(s->hash, s->tmp_hash, 801 ECRYPTFS_TAG_70_DIGEST_SIZE); 802 } 803 if (s->block_aligned_filename[s->j] == '\0') 804 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 805 } 806 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 807 filename_size); 808 rc = virt_to_scatterlist(s->block_aligned_filename, 809 s->block_aligned_filename_size, s->src_sg, 2); 810 if (rc < 1) { 811 printk(KERN_ERR "%s: Internal error whilst attempting to " 812 "convert filename memory to scatterlist; rc = [%d]. " 813 "block_aligned_filename_size = [%zd]\n", __func__, rc, 814 s->block_aligned_filename_size); 815 goto out_release_free_unlock; 816 } 817 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 818 s->dst_sg, 2); 819 if (rc < 1) { 820 printk(KERN_ERR "%s: Internal error whilst attempting to " 821 "convert encrypted filename memory to scatterlist; " 822 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 823 __func__, rc, s->block_aligned_filename_size); 824 goto out_release_free_unlock; 825 } 826 /* The characters in the first block effectively do the job 827 * of the IV here, so we just use 0's for the IV. Note the 828 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 829 * >= ECRYPTFS_MAX_IV_BYTES. */ 830 rc = crypto_skcipher_setkey( 831 s->skcipher_tfm, 832 s->auth_tok->token.password.session_key_encryption_key, 833 mount_crypt_stat->global_default_fn_cipher_key_bytes); 834 if (rc < 0) { 835 printk(KERN_ERR "%s: Error setting key for crypto context; " 836 "rc = [%d]. s->auth_tok->token.password.session_key_" 837 "encryption_key = [0x%p]; mount_crypt_stat->" 838 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 839 rc, 840 s->auth_tok->token.password.session_key_encryption_key, 841 mount_crypt_stat->global_default_fn_cipher_key_bytes); 842 goto out_release_free_unlock; 843 } 844 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 845 s->block_aligned_filename_size, s->iv); 846 rc = crypto_skcipher_encrypt(s->skcipher_req); 847 if (rc) { 848 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 849 "rc = [%d]\n", __func__, rc); 850 goto out_release_free_unlock; 851 } 852 s->i += s->block_aligned_filename_size; 853 (*packet_size) = s->i; 854 (*remaining_bytes) -= (*packet_size); 855 out_release_free_unlock: 856 crypto_free_shash(s->hash_tfm); 857 out_free_unlock: 858 kzfree(s->block_aligned_filename); 859 out_unlock: 860 mutex_unlock(s->tfm_mutex); 861 out: 862 if (auth_tok_key) { 863 up_write(&(auth_tok_key->sem)); 864 key_put(auth_tok_key); 865 } 866 skcipher_request_free(s->skcipher_req); 867 kzfree(s->hash_desc); 868 kfree(s); 869 return rc; 870 } 871 872 struct ecryptfs_parse_tag_70_packet_silly_stack { 873 u8 cipher_code; 874 size_t max_packet_size; 875 size_t packet_size_len; 876 size_t parsed_tag_70_packet_size; 877 size_t block_aligned_filename_size; 878 size_t block_size; 879 size_t i; 880 struct mutex *tfm_mutex; 881 char *decrypted_filename; 882 struct ecryptfs_auth_tok *auth_tok; 883 struct scatterlist src_sg[2]; 884 struct scatterlist dst_sg[2]; 885 struct crypto_skcipher *skcipher_tfm; 886 struct skcipher_request *skcipher_req; 887 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 888 char iv[ECRYPTFS_MAX_IV_BYTES]; 889 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; 890 }; 891 892 /** 893 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 894 * @filename: This function kmalloc's the memory for the filename 895 * @filename_size: This function sets this to the amount of memory 896 * kmalloc'd for the filename 897 * @packet_size: This function sets this to the the number of octets 898 * in the packet parsed 899 * @mount_crypt_stat: The mount-wide cryptographic context 900 * @data: The memory location containing the start of the tag 70 901 * packet 902 * @max_packet_size: The maximum legal size of the packet to be parsed 903 * from @data 904 * 905 * Returns zero on success; non-zero otherwise 906 */ 907 int 908 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 909 size_t *packet_size, 910 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 911 char *data, size_t max_packet_size) 912 { 913 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 914 struct key *auth_tok_key = NULL; 915 int rc = 0; 916 917 (*packet_size) = 0; 918 (*filename_size) = 0; 919 (*filename) = NULL; 920 s = kzalloc(sizeof(*s), GFP_KERNEL); 921 if (!s) { 922 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 923 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 924 return -ENOMEM; 925 } 926 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 927 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 928 "at least [%d]\n", __func__, max_packet_size, 929 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 930 rc = -EINVAL; 931 goto out; 932 } 933 /* Octet 0: Tag 70 identifier 934 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 935 * and block-aligned encrypted filename size) 936 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 937 * Octet N2-N3: Cipher identifier (1 octet) 938 * Octets N3-N4: Block-aligned encrypted filename 939 * - Consists of a minimum number of random numbers, a \0 940 * separator, and then the filename */ 941 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 942 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 943 "tag [0x%.2x]\n", __func__, 944 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 945 rc = -EINVAL; 946 goto out; 947 } 948 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 949 &s->parsed_tag_70_packet_size, 950 &s->packet_size_len); 951 if (rc) { 952 printk(KERN_WARNING "%s: Error parsing packet length; " 953 "rc = [%d]\n", __func__, rc); 954 goto out; 955 } 956 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 957 - ECRYPTFS_SIG_SIZE - 1); 958 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 959 > max_packet_size) { 960 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 961 "size is [%zd]\n", __func__, max_packet_size, 962 (1 + s->packet_size_len + 1 963 + s->block_aligned_filename_size)); 964 rc = -EINVAL; 965 goto out; 966 } 967 (*packet_size) += s->packet_size_len; 968 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 969 ECRYPTFS_SIG_SIZE); 970 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 971 (*packet_size) += ECRYPTFS_SIG_SIZE; 972 s->cipher_code = data[(*packet_size)++]; 973 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 974 if (rc) { 975 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 976 __func__, s->cipher_code); 977 goto out; 978 } 979 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 980 &s->auth_tok, mount_crypt_stat, 981 s->fnek_sig_hex); 982 if (rc) { 983 printk(KERN_ERR "%s: Error attempting to find auth tok for " 984 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 985 rc); 986 goto out; 987 } 988 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm, 989 &s->tfm_mutex, 990 s->cipher_string); 991 if (unlikely(rc)) { 992 printk(KERN_ERR "Internal error whilst attempting to get " 993 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 994 s->cipher_string, rc); 995 goto out; 996 } 997 mutex_lock(s->tfm_mutex); 998 rc = virt_to_scatterlist(&data[(*packet_size)], 999 s->block_aligned_filename_size, s->src_sg, 2); 1000 if (rc < 1) { 1001 printk(KERN_ERR "%s: Internal error whilst attempting to " 1002 "convert encrypted filename memory to scatterlist; " 1003 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1004 __func__, rc, s->block_aligned_filename_size); 1005 goto out_unlock; 1006 } 1007 (*packet_size) += s->block_aligned_filename_size; 1008 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 1009 GFP_KERNEL); 1010 if (!s->decrypted_filename) { 1011 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1012 "kmalloc [%zd] bytes\n", __func__, 1013 s->block_aligned_filename_size); 1014 rc = -ENOMEM; 1015 goto out_unlock; 1016 } 1017 rc = virt_to_scatterlist(s->decrypted_filename, 1018 s->block_aligned_filename_size, s->dst_sg, 2); 1019 if (rc < 1) { 1020 printk(KERN_ERR "%s: Internal error whilst attempting to " 1021 "convert decrypted filename memory to scatterlist; " 1022 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1023 __func__, rc, s->block_aligned_filename_size); 1024 goto out_free_unlock; 1025 } 1026 1027 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 1028 if (!s->skcipher_req) { 1029 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1030 "skcipher_request_alloc for %s\n", __func__, 1031 crypto_skcipher_driver_name(s->skcipher_tfm)); 1032 rc = -ENOMEM; 1033 goto out_free_unlock; 1034 } 1035 1036 skcipher_request_set_callback(s->skcipher_req, 1037 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 1038 1039 /* The characters in the first block effectively do the job of 1040 * the IV here, so we just use 0's for the IV. Note the 1041 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1042 * >= ECRYPTFS_MAX_IV_BYTES. */ 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_skcipher_setkey( 1052 s->skcipher_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 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 1066 s->block_aligned_filename_size, s->iv); 1067 rc = crypto_skcipher_decrypt(s->skcipher_req); 1068 if (rc) { 1069 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1070 "rc = [%d]\n", __func__, rc); 1071 goto out_free_unlock; 1072 } 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 skcipher_request_free(s->skcipher_req); 1116 kfree(s); 1117 return rc; 1118 } 1119 1120 static int 1121 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1122 { 1123 int rc = 0; 1124 1125 (*sig) = NULL; 1126 switch (auth_tok->token_type) { 1127 case ECRYPTFS_PASSWORD: 1128 (*sig) = auth_tok->token.password.signature; 1129 break; 1130 case ECRYPTFS_PRIVATE_KEY: 1131 (*sig) = auth_tok->token.private_key.signature; 1132 break; 1133 default: 1134 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1135 auth_tok->token_type); 1136 rc = -EINVAL; 1137 } 1138 return rc; 1139 } 1140 1141 /** 1142 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1143 * @auth_tok: The key authentication token used to decrypt the session key 1144 * @crypt_stat: The cryptographic context 1145 * 1146 * Returns zero on success; non-zero error otherwise. 1147 */ 1148 static int 1149 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1150 struct ecryptfs_crypt_stat *crypt_stat) 1151 { 1152 u8 cipher_code = 0; 1153 struct ecryptfs_msg_ctx *msg_ctx; 1154 struct ecryptfs_message *msg = NULL; 1155 char *auth_tok_sig; 1156 char *payload = NULL; 1157 size_t payload_len = 0; 1158 int rc; 1159 1160 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1161 if (rc) { 1162 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1163 auth_tok->token_type); 1164 goto out; 1165 } 1166 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1167 &payload, &payload_len); 1168 if (rc) { 1169 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1170 goto out; 1171 } 1172 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1173 if (rc) { 1174 ecryptfs_printk(KERN_ERR, "Error sending message to " 1175 "ecryptfsd: %d\n", rc); 1176 goto out; 1177 } 1178 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1179 if (rc) { 1180 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1181 "from the user space daemon\n"); 1182 rc = -EIO; 1183 goto out; 1184 } 1185 rc = parse_tag_65_packet(&(auth_tok->session_key), 1186 &cipher_code, msg); 1187 if (rc) { 1188 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1189 rc); 1190 goto out; 1191 } 1192 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1193 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1194 auth_tok->session_key.decrypted_key_size); 1195 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1196 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1197 if (rc) { 1198 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1199 cipher_code) 1200 goto out; 1201 } 1202 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1203 if (ecryptfs_verbosity > 0) { 1204 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1205 ecryptfs_dump_hex(crypt_stat->key, 1206 crypt_stat->key_size); 1207 } 1208 out: 1209 kfree(msg); 1210 kfree(payload); 1211 return rc; 1212 } 1213 1214 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1215 { 1216 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1217 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1218 1219 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1220 auth_tok_list_head, list) { 1221 list_del(&auth_tok_list_item->list); 1222 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1223 auth_tok_list_item); 1224 } 1225 } 1226 1227 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1228 1229 /** 1230 * parse_tag_1_packet 1231 * @crypt_stat: The cryptographic context to modify based on packet contents 1232 * @data: The raw bytes of the packet. 1233 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1234 * a new authentication token will be placed at the 1235 * end of this list for this packet. 1236 * @new_auth_tok: Pointer to a pointer to memory that this function 1237 * allocates; sets the memory address of the pointer to 1238 * NULL on error. This object is added to the 1239 * auth_tok_list. 1240 * @packet_size: This function writes the size of the parsed packet 1241 * into this memory location; zero on error. 1242 * @max_packet_size: The maximum allowable packet size 1243 * 1244 * Returns zero on success; non-zero on error. 1245 */ 1246 static int 1247 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1248 unsigned char *data, struct list_head *auth_tok_list, 1249 struct ecryptfs_auth_tok **new_auth_tok, 1250 size_t *packet_size, size_t max_packet_size) 1251 { 1252 size_t body_size; 1253 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1254 size_t length_size; 1255 int rc = 0; 1256 1257 (*packet_size) = 0; 1258 (*new_auth_tok) = NULL; 1259 /** 1260 * This format is inspired by OpenPGP; see RFC 2440 1261 * packet tag 1 1262 * 1263 * Tag 1 identifier (1 byte) 1264 * Max Tag 1 packet size (max 3 bytes) 1265 * Version (1 byte) 1266 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1267 * Cipher identifier (1 byte) 1268 * Encrypted key size (arbitrary) 1269 * 1270 * 12 bytes minimum packet size 1271 */ 1272 if (unlikely(max_packet_size < 12)) { 1273 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1274 rc = -EINVAL; 1275 goto out; 1276 } 1277 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1278 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1279 ECRYPTFS_TAG_1_PACKET_TYPE); 1280 rc = -EINVAL; 1281 goto out; 1282 } 1283 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1284 * at end of function upon failure */ 1285 auth_tok_list_item = 1286 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1287 GFP_KERNEL); 1288 if (!auth_tok_list_item) { 1289 printk(KERN_ERR "Unable to allocate memory\n"); 1290 rc = -ENOMEM; 1291 goto out; 1292 } 1293 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1294 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1295 &length_size); 1296 if (rc) { 1297 printk(KERN_WARNING "Error parsing packet length; " 1298 "rc = [%d]\n", rc); 1299 goto out_free; 1300 } 1301 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1302 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1303 rc = -EINVAL; 1304 goto out_free; 1305 } 1306 (*packet_size) += length_size; 1307 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1308 printk(KERN_WARNING "Packet size exceeds max\n"); 1309 rc = -EINVAL; 1310 goto out_free; 1311 } 1312 if (unlikely(data[(*packet_size)++] != 0x03)) { 1313 printk(KERN_WARNING "Unknown version number [%d]\n", 1314 data[(*packet_size) - 1]); 1315 rc = -EINVAL; 1316 goto out_free; 1317 } 1318 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1319 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1320 *packet_size += ECRYPTFS_SIG_SIZE; 1321 /* This byte is skipped because the kernel does not need to 1322 * know which public key encryption algorithm was used */ 1323 (*packet_size)++; 1324 (*new_auth_tok)->session_key.encrypted_key_size = 1325 body_size - (ECRYPTFS_SIG_SIZE + 2); 1326 if ((*new_auth_tok)->session_key.encrypted_key_size 1327 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1328 printk(KERN_WARNING "Tag 1 packet contains key larger " 1329 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); 1330 rc = -EINVAL; 1331 goto out; 1332 } 1333 memcpy((*new_auth_tok)->session_key.encrypted_key, 1334 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1335 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1336 (*new_auth_tok)->session_key.flags &= 1337 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1338 (*new_auth_tok)->session_key.flags |= 1339 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1340 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1341 (*new_auth_tok)->flags = 0; 1342 (*new_auth_tok)->session_key.flags &= 1343 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1344 (*new_auth_tok)->session_key.flags &= 1345 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1346 list_add(&auth_tok_list_item->list, auth_tok_list); 1347 goto out; 1348 out_free: 1349 (*new_auth_tok) = NULL; 1350 memset(auth_tok_list_item, 0, 1351 sizeof(struct ecryptfs_auth_tok_list_item)); 1352 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1353 auth_tok_list_item); 1354 out: 1355 if (rc) 1356 (*packet_size) = 0; 1357 return rc; 1358 } 1359 1360 /** 1361 * parse_tag_3_packet 1362 * @crypt_stat: The cryptographic context to modify based on packet 1363 * contents. 1364 * @data: The raw bytes of the packet. 1365 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1366 * a new authentication token will be placed at the end 1367 * of this list for this packet. 1368 * @new_auth_tok: Pointer to a pointer to memory that this function 1369 * allocates; sets the memory address of the pointer to 1370 * NULL on error. This object is added to the 1371 * auth_tok_list. 1372 * @packet_size: This function writes the size of the parsed packet 1373 * into this memory location; zero on error. 1374 * @max_packet_size: maximum number of bytes to parse 1375 * 1376 * Returns zero on success; non-zero on error. 1377 */ 1378 static int 1379 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1380 unsigned char *data, struct list_head *auth_tok_list, 1381 struct ecryptfs_auth_tok **new_auth_tok, 1382 size_t *packet_size, size_t max_packet_size) 1383 { 1384 size_t body_size; 1385 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1386 size_t length_size; 1387 int rc = 0; 1388 1389 (*packet_size) = 0; 1390 (*new_auth_tok) = NULL; 1391 /** 1392 *This format is inspired by OpenPGP; see RFC 2440 1393 * packet tag 3 1394 * 1395 * Tag 3 identifier (1 byte) 1396 * Max Tag 3 packet size (max 3 bytes) 1397 * Version (1 byte) 1398 * Cipher code (1 byte) 1399 * S2K specifier (1 byte) 1400 * Hash identifier (1 byte) 1401 * Salt (ECRYPTFS_SALT_SIZE) 1402 * Hash iterations (1 byte) 1403 * Encrypted key (arbitrary) 1404 * 1405 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1406 */ 1407 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1408 printk(KERN_ERR "Max packet size too large\n"); 1409 rc = -EINVAL; 1410 goto out; 1411 } 1412 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1413 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1414 ECRYPTFS_TAG_3_PACKET_TYPE); 1415 rc = -EINVAL; 1416 goto out; 1417 } 1418 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1419 * at end of function upon failure */ 1420 auth_tok_list_item = 1421 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1422 if (!auth_tok_list_item) { 1423 printk(KERN_ERR "Unable to allocate memory\n"); 1424 rc = -ENOMEM; 1425 goto out; 1426 } 1427 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1428 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1429 &length_size); 1430 if (rc) { 1431 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1432 rc); 1433 goto out_free; 1434 } 1435 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1436 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1437 rc = -EINVAL; 1438 goto out_free; 1439 } 1440 (*packet_size) += length_size; 1441 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1442 printk(KERN_ERR "Packet size exceeds max\n"); 1443 rc = -EINVAL; 1444 goto out_free; 1445 } 1446 (*new_auth_tok)->session_key.encrypted_key_size = 1447 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1448 if ((*new_auth_tok)->session_key.encrypted_key_size 1449 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1450 printk(KERN_WARNING "Tag 3 packet contains key larger " 1451 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1452 rc = -EINVAL; 1453 goto out_free; 1454 } 1455 if (unlikely(data[(*packet_size)++] != 0x04)) { 1456 printk(KERN_WARNING "Unknown version number [%d]\n", 1457 data[(*packet_size) - 1]); 1458 rc = -EINVAL; 1459 goto out_free; 1460 } 1461 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1462 (u16)data[(*packet_size)]); 1463 if (rc) 1464 goto out_free; 1465 /* A little extra work to differentiate among the AES key 1466 * sizes; see RFC2440 */ 1467 switch(data[(*packet_size)++]) { 1468 case RFC2440_CIPHER_AES_192: 1469 crypt_stat->key_size = 24; 1470 break; 1471 default: 1472 crypt_stat->key_size = 1473 (*new_auth_tok)->session_key.encrypted_key_size; 1474 } 1475 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1476 if (rc) 1477 goto out_free; 1478 if (unlikely(data[(*packet_size)++] != 0x03)) { 1479 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1480 rc = -ENOSYS; 1481 goto out_free; 1482 } 1483 /* TODO: finish the hash mapping */ 1484 switch (data[(*packet_size)++]) { 1485 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1486 /* Choose MD5 */ 1487 memcpy((*new_auth_tok)->token.password.salt, 1488 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1489 (*packet_size) += ECRYPTFS_SALT_SIZE; 1490 /* This conversion was taken straight from RFC2440 */ 1491 (*new_auth_tok)->token.password.hash_iterations = 1492 ((u32) 16 + (data[(*packet_size)] & 15)) 1493 << ((data[(*packet_size)] >> 4) + 6); 1494 (*packet_size)++; 1495 /* Friendly reminder: 1496 * (*new_auth_tok)->session_key.encrypted_key_size = 1497 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1498 memcpy((*new_auth_tok)->session_key.encrypted_key, 1499 &data[(*packet_size)], 1500 (*new_auth_tok)->session_key.encrypted_key_size); 1501 (*packet_size) += 1502 (*new_auth_tok)->session_key.encrypted_key_size; 1503 (*new_auth_tok)->session_key.flags &= 1504 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1505 (*new_auth_tok)->session_key.flags |= 1506 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1507 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1508 break; 1509 default: 1510 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1511 "[%d]\n", data[(*packet_size) - 1]); 1512 rc = -ENOSYS; 1513 goto out_free; 1514 } 1515 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1516 /* TODO: Parametarize; we might actually want userspace to 1517 * decrypt the session key. */ 1518 (*new_auth_tok)->session_key.flags &= 1519 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1520 (*new_auth_tok)->session_key.flags &= 1521 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1522 list_add(&auth_tok_list_item->list, auth_tok_list); 1523 goto out; 1524 out_free: 1525 (*new_auth_tok) = NULL; 1526 memset(auth_tok_list_item, 0, 1527 sizeof(struct ecryptfs_auth_tok_list_item)); 1528 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1529 auth_tok_list_item); 1530 out: 1531 if (rc) 1532 (*packet_size) = 0; 1533 return rc; 1534 } 1535 1536 /** 1537 * parse_tag_11_packet 1538 * @data: The raw bytes of the packet 1539 * @contents: This function writes the data contents of the literal 1540 * packet into this memory location 1541 * @max_contents_bytes: The maximum number of bytes that this function 1542 * is allowed to write into contents 1543 * @tag_11_contents_size: This function writes the size of the parsed 1544 * contents into this memory location; zero on 1545 * error 1546 * @packet_size: This function writes the size of the parsed packet 1547 * into this memory location; zero on error 1548 * @max_packet_size: maximum number of bytes to parse 1549 * 1550 * Returns zero on success; non-zero on error. 1551 */ 1552 static int 1553 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1554 size_t max_contents_bytes, size_t *tag_11_contents_size, 1555 size_t *packet_size, size_t max_packet_size) 1556 { 1557 size_t body_size; 1558 size_t length_size; 1559 int rc = 0; 1560 1561 (*packet_size) = 0; 1562 (*tag_11_contents_size) = 0; 1563 /* This format is inspired by OpenPGP; see RFC 2440 1564 * packet tag 11 1565 * 1566 * Tag 11 identifier (1 byte) 1567 * Max Tag 11 packet size (max 3 bytes) 1568 * Binary format specifier (1 byte) 1569 * Filename length (1 byte) 1570 * Filename ("_CONSOLE") (8 bytes) 1571 * Modification date (4 bytes) 1572 * Literal data (arbitrary) 1573 * 1574 * We need at least 16 bytes of data for the packet to even be 1575 * valid. 1576 */ 1577 if (max_packet_size < 16) { 1578 printk(KERN_ERR "Maximum packet size too small\n"); 1579 rc = -EINVAL; 1580 goto out; 1581 } 1582 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1583 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1584 rc = -EINVAL; 1585 goto out; 1586 } 1587 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1588 &length_size); 1589 if (rc) { 1590 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1591 goto out; 1592 } 1593 if (body_size < 14) { 1594 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1595 rc = -EINVAL; 1596 goto out; 1597 } 1598 (*packet_size) += length_size; 1599 (*tag_11_contents_size) = (body_size - 14); 1600 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1601 printk(KERN_ERR "Packet size exceeds max\n"); 1602 rc = -EINVAL; 1603 goto out; 1604 } 1605 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1606 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1607 "expected size\n"); 1608 rc = -EINVAL; 1609 goto out; 1610 } 1611 if (data[(*packet_size)++] != 0x62) { 1612 printk(KERN_WARNING "Unrecognizable packet\n"); 1613 rc = -EINVAL; 1614 goto out; 1615 } 1616 if (data[(*packet_size)++] != 0x08) { 1617 printk(KERN_WARNING "Unrecognizable packet\n"); 1618 rc = -EINVAL; 1619 goto out; 1620 } 1621 (*packet_size) += 12; /* Ignore filename and modification date */ 1622 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1623 (*packet_size) += (*tag_11_contents_size); 1624 out: 1625 if (rc) { 1626 (*packet_size) = 0; 1627 (*tag_11_contents_size) = 0; 1628 } 1629 return rc; 1630 } 1631 1632 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1633 struct ecryptfs_auth_tok **auth_tok, 1634 char *sig) 1635 { 1636 int rc = 0; 1637 1638 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1639 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1640 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1641 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1642 printk(KERN_ERR "Could not find key with description: [%s]\n", 1643 sig); 1644 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1645 (*auth_tok_key) = NULL; 1646 goto out; 1647 } 1648 } 1649 down_write(&(*auth_tok_key)->sem); 1650 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1651 if (rc) { 1652 up_write(&(*auth_tok_key)->sem); 1653 key_put(*auth_tok_key); 1654 (*auth_tok_key) = NULL; 1655 goto out; 1656 } 1657 out: 1658 return rc; 1659 } 1660 1661 /** 1662 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1663 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1664 * @crypt_stat: The cryptographic context 1665 * 1666 * Returns zero on success; non-zero error otherwise 1667 */ 1668 static int 1669 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1670 struct ecryptfs_crypt_stat *crypt_stat) 1671 { 1672 struct scatterlist dst_sg[2]; 1673 struct scatterlist src_sg[2]; 1674 struct mutex *tfm_mutex; 1675 struct crypto_skcipher *tfm; 1676 struct skcipher_request *req = NULL; 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(&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 req = skcipher_request_alloc(tfm, GFP_KERNEL); 1719 if (!req) { 1720 mutex_unlock(tfm_mutex); 1721 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1722 "skcipher_request_alloc for %s\n", __func__, 1723 crypto_skcipher_driver_name(tfm)); 1724 rc = -ENOMEM; 1725 goto out; 1726 } 1727 1728 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 1729 NULL, NULL); 1730 rc = crypto_skcipher_setkey( 1731 tfm, auth_tok->token.password.session_key_encryption_key, 1732 crypt_stat->key_size); 1733 if (unlikely(rc < 0)) { 1734 mutex_unlock(tfm_mutex); 1735 printk(KERN_ERR "Error setting key for crypto context\n"); 1736 rc = -EINVAL; 1737 goto out; 1738 } 1739 skcipher_request_set_crypt(req, src_sg, dst_sg, 1740 auth_tok->session_key.encrypted_key_size, 1741 NULL); 1742 rc = crypto_skcipher_decrypt(req); 1743 mutex_unlock(tfm_mutex); 1744 if (unlikely(rc)) { 1745 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1746 goto out; 1747 } 1748 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1749 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1750 auth_tok->session_key.decrypted_key_size); 1751 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1752 if (unlikely(ecryptfs_verbosity > 0)) { 1753 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1754 crypt_stat->key_size); 1755 ecryptfs_dump_hex(crypt_stat->key, 1756 crypt_stat->key_size); 1757 } 1758 out: 1759 skcipher_request_free(req); 1760 return rc; 1761 } 1762 1763 /** 1764 * ecryptfs_parse_packet_set 1765 * @crypt_stat: The cryptographic context 1766 * @src: Virtual address of region of memory containing the packets 1767 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1768 * 1769 * Get crypt_stat to have the file's session key if the requisite key 1770 * is available to decrypt the session key. 1771 * 1772 * Returns Zero if a valid authentication token was retrieved and 1773 * processed; negative value for file not encrypted or for error 1774 * conditions. 1775 */ 1776 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1777 unsigned char *src, 1778 struct dentry *ecryptfs_dentry) 1779 { 1780 size_t i = 0; 1781 size_t found_auth_tok; 1782 size_t next_packet_is_auth_tok_packet; 1783 struct list_head auth_tok_list; 1784 struct ecryptfs_auth_tok *matching_auth_tok; 1785 struct ecryptfs_auth_tok *candidate_auth_tok; 1786 char *candidate_auth_tok_sig; 1787 size_t packet_size; 1788 struct ecryptfs_auth_tok *new_auth_tok; 1789 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1790 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1791 size_t tag_11_contents_size; 1792 size_t tag_11_packet_size; 1793 struct key *auth_tok_key = NULL; 1794 int rc = 0; 1795 1796 INIT_LIST_HEAD(&auth_tok_list); 1797 /* Parse the header to find as many packets as we can; these will be 1798 * added the our &auth_tok_list */ 1799 next_packet_is_auth_tok_packet = 1; 1800 while (next_packet_is_auth_tok_packet) { 1801 size_t max_packet_size = ((PAGE_SIZE - 8) - i); 1802 1803 switch (src[i]) { 1804 case ECRYPTFS_TAG_3_PACKET_TYPE: 1805 rc = parse_tag_3_packet(crypt_stat, 1806 (unsigned char *)&src[i], 1807 &auth_tok_list, &new_auth_tok, 1808 &packet_size, max_packet_size); 1809 if (rc) { 1810 ecryptfs_printk(KERN_ERR, "Error parsing " 1811 "tag 3 packet\n"); 1812 rc = -EIO; 1813 goto out_wipe_list; 1814 } 1815 i += packet_size; 1816 rc = parse_tag_11_packet((unsigned char *)&src[i], 1817 sig_tmp_space, 1818 ECRYPTFS_SIG_SIZE, 1819 &tag_11_contents_size, 1820 &tag_11_packet_size, 1821 max_packet_size); 1822 if (rc) { 1823 ecryptfs_printk(KERN_ERR, "No valid " 1824 "(ecryptfs-specific) literal " 1825 "packet containing " 1826 "authentication token " 1827 "signature found after " 1828 "tag 3 packet\n"); 1829 rc = -EIO; 1830 goto out_wipe_list; 1831 } 1832 i += tag_11_packet_size; 1833 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1834 ecryptfs_printk(KERN_ERR, "Expected " 1835 "signature of size [%d]; " 1836 "read size [%zd]\n", 1837 ECRYPTFS_SIG_SIZE, 1838 tag_11_contents_size); 1839 rc = -EIO; 1840 goto out_wipe_list; 1841 } 1842 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1843 sig_tmp_space, tag_11_contents_size); 1844 new_auth_tok->token.password.signature[ 1845 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1846 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1847 break; 1848 case ECRYPTFS_TAG_1_PACKET_TYPE: 1849 rc = parse_tag_1_packet(crypt_stat, 1850 (unsigned char *)&src[i], 1851 &auth_tok_list, &new_auth_tok, 1852 &packet_size, max_packet_size); 1853 if (rc) { 1854 ecryptfs_printk(KERN_ERR, "Error parsing " 1855 "tag 1 packet\n"); 1856 rc = -EIO; 1857 goto out_wipe_list; 1858 } 1859 i += packet_size; 1860 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1861 break; 1862 case ECRYPTFS_TAG_11_PACKET_TYPE: 1863 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1864 "(Tag 11 not allowed by itself)\n"); 1865 rc = -EIO; 1866 goto out_wipe_list; 1867 default: 1868 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1869 "of the file header; hex value of " 1870 "character is [0x%.2x]\n", i, src[i]); 1871 next_packet_is_auth_tok_packet = 0; 1872 } 1873 } 1874 if (list_empty(&auth_tok_list)) { 1875 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1876 "eCryptfs file; this is not supported in this version " 1877 "of the eCryptfs kernel module\n"); 1878 rc = -EINVAL; 1879 goto out; 1880 } 1881 /* auth_tok_list contains the set of authentication tokens 1882 * parsed from the metadata. We need to find a matching 1883 * authentication token that has the secret component(s) 1884 * necessary to decrypt the EFEK in the auth_tok parsed from 1885 * the metadata. There may be several potential matches, but 1886 * just one will be sufficient to decrypt to get the FEK. */ 1887 find_next_matching_auth_tok: 1888 found_auth_tok = 0; 1889 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1890 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1891 if (unlikely(ecryptfs_verbosity > 0)) { 1892 ecryptfs_printk(KERN_DEBUG, 1893 "Considering cadidate auth tok:\n"); 1894 ecryptfs_dump_auth_tok(candidate_auth_tok); 1895 } 1896 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1897 candidate_auth_tok); 1898 if (rc) { 1899 printk(KERN_ERR 1900 "Unrecognized candidate auth tok type: [%d]\n", 1901 candidate_auth_tok->token_type); 1902 rc = -EINVAL; 1903 goto out_wipe_list; 1904 } 1905 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1906 &matching_auth_tok, 1907 crypt_stat->mount_crypt_stat, 1908 candidate_auth_tok_sig); 1909 if (!rc) { 1910 found_auth_tok = 1; 1911 goto found_matching_auth_tok; 1912 } 1913 } 1914 if (!found_auth_tok) { 1915 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1916 "authentication token\n"); 1917 rc = -EIO; 1918 goto out_wipe_list; 1919 } 1920 found_matching_auth_tok: 1921 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1922 memcpy(&(candidate_auth_tok->token.private_key), 1923 &(matching_auth_tok->token.private_key), 1924 sizeof(struct ecryptfs_private_key)); 1925 up_write(&(auth_tok_key->sem)); 1926 key_put(auth_tok_key); 1927 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1928 crypt_stat); 1929 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1930 memcpy(&(candidate_auth_tok->token.password), 1931 &(matching_auth_tok->token.password), 1932 sizeof(struct ecryptfs_password)); 1933 up_write(&(auth_tok_key->sem)); 1934 key_put(auth_tok_key); 1935 rc = decrypt_passphrase_encrypted_session_key( 1936 candidate_auth_tok, crypt_stat); 1937 } else { 1938 up_write(&(auth_tok_key->sem)); 1939 key_put(auth_tok_key); 1940 rc = -EINVAL; 1941 } 1942 if (rc) { 1943 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1944 1945 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1946 "session key for authentication token with sig " 1947 "[%.*s]; rc = [%d]. Removing auth tok " 1948 "candidate from the list and searching for " 1949 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1950 candidate_auth_tok_sig, rc); 1951 list_for_each_entry_safe(auth_tok_list_item, 1952 auth_tok_list_item_tmp, 1953 &auth_tok_list, list) { 1954 if (candidate_auth_tok 1955 == &auth_tok_list_item->auth_tok) { 1956 list_del(&auth_tok_list_item->list); 1957 kmem_cache_free( 1958 ecryptfs_auth_tok_list_item_cache, 1959 auth_tok_list_item); 1960 goto find_next_matching_auth_tok; 1961 } 1962 } 1963 BUG(); 1964 } 1965 rc = ecryptfs_compute_root_iv(crypt_stat); 1966 if (rc) { 1967 ecryptfs_printk(KERN_ERR, "Error computing " 1968 "the root IV\n"); 1969 goto out_wipe_list; 1970 } 1971 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1972 if (rc) { 1973 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1974 "context for cipher [%s]; rc = [%d]\n", 1975 crypt_stat->cipher, rc); 1976 } 1977 out_wipe_list: 1978 wipe_auth_tok_list(&auth_tok_list); 1979 out: 1980 return rc; 1981 } 1982 1983 static int 1984 pki_encrypt_session_key(struct key *auth_tok_key, 1985 struct ecryptfs_auth_tok *auth_tok, 1986 struct ecryptfs_crypt_stat *crypt_stat, 1987 struct ecryptfs_key_record *key_rec) 1988 { 1989 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1990 char *payload = NULL; 1991 size_t payload_len = 0; 1992 struct ecryptfs_message *msg; 1993 int rc; 1994 1995 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1996 ecryptfs_code_for_cipher_string( 1997 crypt_stat->cipher, 1998 crypt_stat->key_size), 1999 crypt_stat, &payload, &payload_len); 2000 up_write(&(auth_tok_key->sem)); 2001 key_put(auth_tok_key); 2002 if (rc) { 2003 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 2004 goto out; 2005 } 2006 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 2007 if (rc) { 2008 ecryptfs_printk(KERN_ERR, "Error sending message to " 2009 "ecryptfsd: %d\n", rc); 2010 goto out; 2011 } 2012 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 2013 if (rc) { 2014 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 2015 "from the user space daemon\n"); 2016 rc = -EIO; 2017 goto out; 2018 } 2019 rc = parse_tag_67_packet(key_rec, msg); 2020 if (rc) 2021 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2022 kfree(msg); 2023 out: 2024 kfree(payload); 2025 return rc; 2026 } 2027 /** 2028 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2029 * @dest: Buffer into which to write the packet 2030 * @remaining_bytes: Maximum number of bytes that can be writtn 2031 * @auth_tok_key: The authentication token key to unlock and put when done with 2032 * @auth_tok 2033 * @auth_tok: The authentication token used for generating the tag 1 packet 2034 * @crypt_stat: The cryptographic context 2035 * @key_rec: The key record struct for the tag 1 packet 2036 * @packet_size: This function will write the number of bytes that end 2037 * up constituting the packet; set to zero on error 2038 * 2039 * Returns zero on success; non-zero on error. 2040 */ 2041 static int 2042 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2043 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2044 struct ecryptfs_crypt_stat *crypt_stat, 2045 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2046 { 2047 size_t i; 2048 size_t encrypted_session_key_valid = 0; 2049 size_t packet_size_length; 2050 size_t max_packet_size; 2051 int rc = 0; 2052 2053 (*packet_size) = 0; 2054 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2055 ECRYPTFS_SIG_SIZE); 2056 encrypted_session_key_valid = 0; 2057 for (i = 0; i < crypt_stat->key_size; i++) 2058 encrypted_session_key_valid |= 2059 auth_tok->session_key.encrypted_key[i]; 2060 if (encrypted_session_key_valid) { 2061 memcpy(key_rec->enc_key, 2062 auth_tok->session_key.encrypted_key, 2063 auth_tok->session_key.encrypted_key_size); 2064 up_write(&(auth_tok_key->sem)); 2065 key_put(auth_tok_key); 2066 goto encrypted_session_key_set; 2067 } 2068 if (auth_tok->session_key.encrypted_key_size == 0) 2069 auth_tok->session_key.encrypted_key_size = 2070 auth_tok->token.private_key.key_size; 2071 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2072 key_rec); 2073 if (rc) { 2074 printk(KERN_ERR "Failed to encrypt session key via a key " 2075 "module; rc = [%d]\n", rc); 2076 goto out; 2077 } 2078 if (ecryptfs_verbosity > 0) { 2079 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2080 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2081 } 2082 encrypted_session_key_set: 2083 /* This format is inspired by OpenPGP; see RFC 2440 2084 * packet tag 1 */ 2085 max_packet_size = (1 /* Tag 1 identifier */ 2086 + 3 /* Max Tag 1 packet size */ 2087 + 1 /* Version */ 2088 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2089 + 1 /* Cipher identifier */ 2090 + key_rec->enc_key_size); /* Encrypted key size */ 2091 if (max_packet_size > (*remaining_bytes)) { 2092 printk(KERN_ERR "Packet length larger than maximum allowable; " 2093 "need up to [%td] bytes, but there are only [%td] " 2094 "available\n", max_packet_size, (*remaining_bytes)); 2095 rc = -EINVAL; 2096 goto out; 2097 } 2098 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2099 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2100 (max_packet_size - 4), 2101 &packet_size_length); 2102 if (rc) { 2103 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2104 "header; cannot generate packet length\n"); 2105 goto out; 2106 } 2107 (*packet_size) += packet_size_length; 2108 dest[(*packet_size)++] = 0x03; /* version 3 */ 2109 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2110 (*packet_size) += ECRYPTFS_SIG_SIZE; 2111 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2112 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2113 key_rec->enc_key_size); 2114 (*packet_size) += key_rec->enc_key_size; 2115 out: 2116 if (rc) 2117 (*packet_size) = 0; 2118 else 2119 (*remaining_bytes) -= (*packet_size); 2120 return rc; 2121 } 2122 2123 /** 2124 * write_tag_11_packet 2125 * @dest: Target into which Tag 11 packet is to be written 2126 * @remaining_bytes: Maximum packet length 2127 * @contents: Byte array of contents to copy in 2128 * @contents_length: Number of bytes in contents 2129 * @packet_length: Length of the Tag 11 packet written; zero on error 2130 * 2131 * Returns zero on success; non-zero on error. 2132 */ 2133 static int 2134 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2135 size_t contents_length, size_t *packet_length) 2136 { 2137 size_t packet_size_length; 2138 size_t max_packet_size; 2139 int rc = 0; 2140 2141 (*packet_length) = 0; 2142 /* This format is inspired by OpenPGP; see RFC 2440 2143 * packet tag 11 */ 2144 max_packet_size = (1 /* Tag 11 identifier */ 2145 + 3 /* Max Tag 11 packet size */ 2146 + 1 /* Binary format specifier */ 2147 + 1 /* Filename length */ 2148 + 8 /* Filename ("_CONSOLE") */ 2149 + 4 /* Modification date */ 2150 + contents_length); /* Literal data */ 2151 if (max_packet_size > (*remaining_bytes)) { 2152 printk(KERN_ERR "Packet length larger than maximum allowable; " 2153 "need up to [%td] bytes, but there are only [%td] " 2154 "available\n", max_packet_size, (*remaining_bytes)); 2155 rc = -EINVAL; 2156 goto out; 2157 } 2158 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2159 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2160 (max_packet_size - 4), 2161 &packet_size_length); 2162 if (rc) { 2163 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2164 "generate packet length. rc = [%d]\n", rc); 2165 goto out; 2166 } 2167 (*packet_length) += packet_size_length; 2168 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2169 dest[(*packet_length)++] = 8; 2170 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2171 (*packet_length) += 8; 2172 memset(&dest[(*packet_length)], 0x00, 4); 2173 (*packet_length) += 4; 2174 memcpy(&dest[(*packet_length)], contents, contents_length); 2175 (*packet_length) += contents_length; 2176 out: 2177 if (rc) 2178 (*packet_length) = 0; 2179 else 2180 (*remaining_bytes) -= (*packet_length); 2181 return rc; 2182 } 2183 2184 /** 2185 * write_tag_3_packet 2186 * @dest: Buffer into which to write the packet 2187 * @remaining_bytes: Maximum number of bytes that can be written 2188 * @auth_tok: Authentication token 2189 * @crypt_stat: The cryptographic context 2190 * @key_rec: encrypted key 2191 * @packet_size: This function will write the number of bytes that end 2192 * up constituting the packet; set to zero on error 2193 * 2194 * Returns zero on success; non-zero on error. 2195 */ 2196 static int 2197 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2198 struct ecryptfs_auth_tok *auth_tok, 2199 struct ecryptfs_crypt_stat *crypt_stat, 2200 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2201 { 2202 size_t i; 2203 size_t encrypted_session_key_valid = 0; 2204 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2205 struct scatterlist dst_sg[2]; 2206 struct scatterlist src_sg[2]; 2207 struct mutex *tfm_mutex = NULL; 2208 u8 cipher_code; 2209 size_t packet_size_length; 2210 size_t max_packet_size; 2211 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2212 crypt_stat->mount_crypt_stat; 2213 struct crypto_skcipher *tfm; 2214 struct skcipher_request *req; 2215 int rc = 0; 2216 2217 (*packet_size) = 0; 2218 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2219 ECRYPTFS_SIG_SIZE); 2220 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 2221 crypt_stat->cipher); 2222 if (unlikely(rc)) { 2223 printk(KERN_ERR "Internal error whilst attempting to get " 2224 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2225 crypt_stat->cipher, rc); 2226 goto out; 2227 } 2228 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2229 printk(KERN_WARNING "No key size specified at mount; " 2230 "defaulting to [%d]\n", 2231 crypto_skcipher_default_keysize(tfm)); 2232 mount_crypt_stat->global_default_cipher_key_size = 2233 crypto_skcipher_default_keysize(tfm); 2234 } 2235 if (crypt_stat->key_size == 0) 2236 crypt_stat->key_size = 2237 mount_crypt_stat->global_default_cipher_key_size; 2238 if (auth_tok->session_key.encrypted_key_size == 0) 2239 auth_tok->session_key.encrypted_key_size = 2240 crypt_stat->key_size; 2241 if (crypt_stat->key_size == 24 2242 && strcmp("aes", crypt_stat->cipher) == 0) { 2243 memset((crypt_stat->key + 24), 0, 8); 2244 auth_tok->session_key.encrypted_key_size = 32; 2245 } else 2246 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2247 key_rec->enc_key_size = 2248 auth_tok->session_key.encrypted_key_size; 2249 encrypted_session_key_valid = 0; 2250 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2251 encrypted_session_key_valid |= 2252 auth_tok->session_key.encrypted_key[i]; 2253 if (encrypted_session_key_valid) { 2254 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2255 "using auth_tok->session_key.encrypted_key, " 2256 "where key_rec->enc_key_size = [%zd]\n", 2257 key_rec->enc_key_size); 2258 memcpy(key_rec->enc_key, 2259 auth_tok->session_key.encrypted_key, 2260 key_rec->enc_key_size); 2261 goto encrypted_session_key_set; 2262 } 2263 if (auth_tok->token.password.flags & 2264 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2265 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2266 "session key encryption key of size [%d]\n", 2267 auth_tok->token.password. 2268 session_key_encryption_key_bytes); 2269 memcpy(session_key_encryption_key, 2270 auth_tok->token.password.session_key_encryption_key, 2271 crypt_stat->key_size); 2272 ecryptfs_printk(KERN_DEBUG, 2273 "Cached session key encryption key:\n"); 2274 if (ecryptfs_verbosity > 0) 2275 ecryptfs_dump_hex(session_key_encryption_key, 16); 2276 } 2277 if (unlikely(ecryptfs_verbosity > 0)) { 2278 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2279 ecryptfs_dump_hex(session_key_encryption_key, 16); 2280 } 2281 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2282 src_sg, 2); 2283 if (rc < 1 || rc > 2) { 2284 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2285 "for crypt_stat session key; expected rc = 1; " 2286 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2287 rc, key_rec->enc_key_size); 2288 rc = -ENOMEM; 2289 goto out; 2290 } 2291 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2292 dst_sg, 2); 2293 if (rc < 1 || rc > 2) { 2294 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2295 "for crypt_stat encrypted session key; " 2296 "expected rc = 1; got rc = [%d]. " 2297 "key_rec->enc_key_size = [%zd]\n", rc, 2298 key_rec->enc_key_size); 2299 rc = -ENOMEM; 2300 goto out; 2301 } 2302 mutex_lock(tfm_mutex); 2303 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key, 2304 crypt_stat->key_size); 2305 if (rc < 0) { 2306 mutex_unlock(tfm_mutex); 2307 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2308 "context; rc = [%d]\n", rc); 2309 goto out; 2310 } 2311 2312 req = skcipher_request_alloc(tfm, GFP_KERNEL); 2313 if (!req) { 2314 mutex_unlock(tfm_mutex); 2315 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " 2316 "attempting to skcipher_request_alloc for " 2317 "%s\n", crypto_skcipher_driver_name(tfm)); 2318 rc = -ENOMEM; 2319 goto out; 2320 } 2321 2322 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 2323 NULL, NULL); 2324 2325 rc = 0; 2326 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2327 crypt_stat->key_size); 2328 skcipher_request_set_crypt(req, src_sg, dst_sg, 2329 (*key_rec).enc_key_size, NULL); 2330 rc = crypto_skcipher_encrypt(req); 2331 mutex_unlock(tfm_mutex); 2332 skcipher_request_free(req); 2333 if (rc) { 2334 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2335 goto out; 2336 } 2337 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2338 if (ecryptfs_verbosity > 0) { 2339 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2340 key_rec->enc_key_size); 2341 ecryptfs_dump_hex(key_rec->enc_key, 2342 key_rec->enc_key_size); 2343 } 2344 encrypted_session_key_set: 2345 /* This format is inspired by OpenPGP; see RFC 2440 2346 * packet tag 3 */ 2347 max_packet_size = (1 /* Tag 3 identifier */ 2348 + 3 /* Max Tag 3 packet size */ 2349 + 1 /* Version */ 2350 + 1 /* Cipher code */ 2351 + 1 /* S2K specifier */ 2352 + 1 /* Hash identifier */ 2353 + ECRYPTFS_SALT_SIZE /* Salt */ 2354 + 1 /* Hash iterations */ 2355 + key_rec->enc_key_size); /* Encrypted key size */ 2356 if (max_packet_size > (*remaining_bytes)) { 2357 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2358 "there are only [%td] available\n", max_packet_size, 2359 (*remaining_bytes)); 2360 rc = -EINVAL; 2361 goto out; 2362 } 2363 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2364 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2365 * to get the number of octets in the actual Tag 3 packet */ 2366 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2367 (max_packet_size - 4), 2368 &packet_size_length); 2369 if (rc) { 2370 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2371 "generate packet length. rc = [%d]\n", rc); 2372 goto out; 2373 } 2374 (*packet_size) += packet_size_length; 2375 dest[(*packet_size)++] = 0x04; /* version 4 */ 2376 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2377 * specified with strings */ 2378 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2379 crypt_stat->key_size); 2380 if (cipher_code == 0) { 2381 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2382 "cipher [%s]\n", crypt_stat->cipher); 2383 rc = -EINVAL; 2384 goto out; 2385 } 2386 dest[(*packet_size)++] = cipher_code; 2387 dest[(*packet_size)++] = 0x03; /* S2K */ 2388 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2389 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2390 ECRYPTFS_SALT_SIZE); 2391 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2392 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2393 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2394 key_rec->enc_key_size); 2395 (*packet_size) += key_rec->enc_key_size; 2396 out: 2397 if (rc) 2398 (*packet_size) = 0; 2399 else 2400 (*remaining_bytes) -= (*packet_size); 2401 return rc; 2402 } 2403 2404 struct kmem_cache *ecryptfs_key_record_cache; 2405 2406 /** 2407 * ecryptfs_generate_key_packet_set 2408 * @dest_base: Virtual address from which to write the key record set 2409 * @crypt_stat: The cryptographic context from which the 2410 * authentication tokens will be retrieved 2411 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2412 * for the global parameters 2413 * @len: The amount written 2414 * @max: The maximum amount of data allowed to be written 2415 * 2416 * Generates a key packet set and writes it to the virtual address 2417 * passed in. 2418 * 2419 * Returns zero on success; non-zero on error. 2420 */ 2421 int 2422 ecryptfs_generate_key_packet_set(char *dest_base, 2423 struct ecryptfs_crypt_stat *crypt_stat, 2424 struct dentry *ecryptfs_dentry, size_t *len, 2425 size_t max) 2426 { 2427 struct ecryptfs_auth_tok *auth_tok; 2428 struct key *auth_tok_key = NULL; 2429 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2430 &ecryptfs_superblock_to_private( 2431 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2432 size_t written; 2433 struct ecryptfs_key_record *key_rec; 2434 struct ecryptfs_key_sig *key_sig; 2435 int rc = 0; 2436 2437 (*len) = 0; 2438 mutex_lock(&crypt_stat->keysig_list_mutex); 2439 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2440 if (!key_rec) { 2441 rc = -ENOMEM; 2442 goto out; 2443 } 2444 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2445 crypt_stat_list) { 2446 memset(key_rec, 0, sizeof(*key_rec)); 2447 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2448 &auth_tok, 2449 mount_crypt_stat, 2450 key_sig->keysig); 2451 if (rc) { 2452 printk(KERN_WARNING "Unable to retrieve auth tok with " 2453 "sig = [%s]\n", key_sig->keysig); 2454 rc = process_find_global_auth_tok_for_sig_err(rc); 2455 goto out_free; 2456 } 2457 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2458 rc = write_tag_3_packet((dest_base + (*len)), 2459 &max, auth_tok, 2460 crypt_stat, key_rec, 2461 &written); 2462 up_write(&(auth_tok_key->sem)); 2463 key_put(auth_tok_key); 2464 if (rc) { 2465 ecryptfs_printk(KERN_WARNING, "Error " 2466 "writing tag 3 packet\n"); 2467 goto out_free; 2468 } 2469 (*len) += written; 2470 /* Write auth tok signature packet */ 2471 rc = write_tag_11_packet((dest_base + (*len)), &max, 2472 key_rec->sig, 2473 ECRYPTFS_SIG_SIZE, &written); 2474 if (rc) { 2475 ecryptfs_printk(KERN_ERR, "Error writing " 2476 "auth tok signature packet\n"); 2477 goto out_free; 2478 } 2479 (*len) += written; 2480 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2481 rc = write_tag_1_packet(dest_base + (*len), &max, 2482 auth_tok_key, auth_tok, 2483 crypt_stat, key_rec, &written); 2484 if (rc) { 2485 ecryptfs_printk(KERN_WARNING, "Error " 2486 "writing tag 1 packet\n"); 2487 goto out_free; 2488 } 2489 (*len) += written; 2490 } else { 2491 up_write(&(auth_tok_key->sem)); 2492 key_put(auth_tok_key); 2493 ecryptfs_printk(KERN_WARNING, "Unsupported " 2494 "authentication token type\n"); 2495 rc = -EINVAL; 2496 goto out_free; 2497 } 2498 } 2499 if (likely(max > 0)) { 2500 dest_base[(*len)] = 0x00; 2501 } else { 2502 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2503 rc = -EIO; 2504 } 2505 out_free: 2506 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2507 out: 2508 if (rc) 2509 (*len) = 0; 2510 mutex_unlock(&crypt_stat->keysig_list_mutex); 2511 return rc; 2512 } 2513 2514 struct kmem_cache *ecryptfs_key_sig_cache; 2515 2516 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2517 { 2518 struct ecryptfs_key_sig *new_key_sig; 2519 2520 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2521 if (!new_key_sig) { 2522 printk(KERN_ERR 2523 "Error allocating from ecryptfs_key_sig_cache\n"); 2524 return -ENOMEM; 2525 } 2526 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2527 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2528 /* Caller must hold keysig_list_mutex */ 2529 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2530 2531 return 0; 2532 } 2533 2534 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2535 2536 int 2537 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2538 char *sig, u32 global_auth_tok_flags) 2539 { 2540 struct ecryptfs_global_auth_tok *new_auth_tok; 2541 int rc = 0; 2542 2543 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2544 GFP_KERNEL); 2545 if (!new_auth_tok) { 2546 rc = -ENOMEM; 2547 printk(KERN_ERR "Error allocating from " 2548 "ecryptfs_global_auth_tok_cache\n"); 2549 goto out; 2550 } 2551 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2552 new_auth_tok->flags = global_auth_tok_flags; 2553 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2554 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2555 list_add(&new_auth_tok->mount_crypt_stat_list, 2556 &mount_crypt_stat->global_auth_tok_list); 2557 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2558 out: 2559 return rc; 2560 } 2561 2562