1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /** 3 * eCryptfs: Linux filesystem encryption layer 4 * In-kernel key management code. Includes functions to parse and 5 * write authentication token-related packets with the underlying 6 * file. 7 * 8 * Copyright (C) 2004-2006 International Business Machines Corp. 9 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> 10 * Michael C. Thompson <mcthomps@us.ibm.com> 11 * Trevor S. Highland <trevor.highland@gmail.com> 12 */ 13 14 #include <crypto/hash.h> 15 #include <crypto/skcipher.h> 16 #include <linux/string.h> 17 #include <linux/pagemap.h> 18 #include <linux/key.h> 19 #include <linux/random.h> 20 #include <linux/scatterlist.h> 21 #include <linux/slab.h> 22 #include "ecryptfs_kernel.h" 23 24 /** 25 * request_key returned an error instead of a valid key address; 26 * determine the type of error, make appropriate log entries, and 27 * return an error code. 28 */ 29 static int process_request_key_err(long err_code) 30 { 31 int rc = 0; 32 33 switch (err_code) { 34 case -ENOKEY: 35 ecryptfs_printk(KERN_WARNING, "No key\n"); 36 rc = -ENOENT; 37 break; 38 case -EKEYEXPIRED: 39 ecryptfs_printk(KERN_WARNING, "Key expired\n"); 40 rc = -ETIME; 41 break; 42 case -EKEYREVOKED: 43 ecryptfs_printk(KERN_WARNING, "Key revoked\n"); 44 rc = -EINVAL; 45 break; 46 default: 47 ecryptfs_printk(KERN_WARNING, "Unknown error code: " 48 "[0x%.16lx]\n", err_code); 49 rc = -EINVAL; 50 } 51 return rc; 52 } 53 54 static int process_find_global_auth_tok_for_sig_err(int err_code) 55 { 56 int rc = err_code; 57 58 switch (err_code) { 59 case -ENOENT: 60 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n"); 61 break; 62 case -EINVAL: 63 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n"); 64 break; 65 default: 66 rc = process_request_key_err(err_code); 67 break; 68 } 69 return rc; 70 } 71 72 /** 73 * ecryptfs_parse_packet_length 74 * @data: Pointer to memory containing length at offset 75 * @size: This function writes the decoded size to this memory 76 * address; zero on error 77 * @length_size: The number of bytes occupied by the encoded length 78 * 79 * Returns zero on success; non-zero on error 80 */ 81 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, 82 size_t *length_size) 83 { 84 int rc = 0; 85 86 (*length_size) = 0; 87 (*size) = 0; 88 if (data[0] < 192) { 89 /* One-byte length */ 90 (*size) = data[0]; 91 (*length_size) = 1; 92 } else if (data[0] < 224) { 93 /* Two-byte length */ 94 (*size) = (data[0] - 192) * 256; 95 (*size) += data[1] + 192; 96 (*length_size) = 2; 97 } else if (data[0] == 255) { 98 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 99 ecryptfs_printk(KERN_ERR, "Five-byte packet length not " 100 "supported\n"); 101 rc = -EINVAL; 102 goto out; 103 } else { 104 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n"); 105 rc = -EINVAL; 106 goto out; 107 } 108 out: 109 return rc; 110 } 111 112 /** 113 * ecryptfs_write_packet_length 114 * @dest: The byte array target into which to write the length. Must 115 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated. 116 * @size: The length to write. 117 * @packet_size_length: The number of bytes used to encode the packet 118 * length is written to this address. 119 * 120 * Returns zero on success; non-zero on error. 121 */ 122 int ecryptfs_write_packet_length(char *dest, size_t size, 123 size_t *packet_size_length) 124 { 125 int rc = 0; 126 127 if (size < 192) { 128 dest[0] = size; 129 (*packet_size_length) = 1; 130 } else if (size < 65536) { 131 dest[0] = (((size - 192) / 256) + 192); 132 dest[1] = ((size - 192) % 256); 133 (*packet_size_length) = 2; 134 } else { 135 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 136 rc = -EINVAL; 137 ecryptfs_printk(KERN_WARNING, 138 "Unsupported packet size: [%zd]\n", size); 139 } 140 return rc; 141 } 142 143 static int 144 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key, 145 char **packet, size_t *packet_len) 146 { 147 size_t i = 0; 148 size_t data_len; 149 size_t packet_size_len; 150 char *message; 151 int rc; 152 153 /* 154 * ***** TAG 64 Packet Format ***** 155 * | Content Type | 1 byte | 156 * | Key Identifier Size | 1 or 2 bytes | 157 * | Key Identifier | arbitrary | 158 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 159 * | Encrypted File Encryption Key | arbitrary | 160 */ 161 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX 162 + session_key->encrypted_key_size); 163 *packet = kmalloc(data_len, GFP_KERNEL); 164 message = *packet; 165 if (!message) { 166 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 167 rc = -ENOMEM; 168 goto out; 169 } 170 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE; 171 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 172 &packet_size_len); 173 if (rc) { 174 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 175 "header; cannot generate packet length\n"); 176 goto out; 177 } 178 i += packet_size_len; 179 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 180 i += ECRYPTFS_SIG_SIZE_HEX; 181 rc = ecryptfs_write_packet_length(&message[i], 182 session_key->encrypted_key_size, 183 &packet_size_len); 184 if (rc) { 185 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 186 "header; cannot generate packet length\n"); 187 goto out; 188 } 189 i += packet_size_len; 190 memcpy(&message[i], session_key->encrypted_key, 191 session_key->encrypted_key_size); 192 i += session_key->encrypted_key_size; 193 *packet_len = i; 194 out: 195 return rc; 196 } 197 198 static int 199 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code, 200 struct ecryptfs_message *msg) 201 { 202 size_t i = 0; 203 char *data; 204 size_t data_len; 205 size_t m_size; 206 size_t message_len; 207 u16 checksum = 0; 208 u16 expected_checksum = 0; 209 int rc; 210 211 /* 212 * ***** TAG 65 Packet Format ***** 213 * | Content Type | 1 byte | 214 * | Status Indicator | 1 byte | 215 * | File Encryption Key Size | 1 or 2 bytes | 216 * | File Encryption Key | arbitrary | 217 */ 218 message_len = msg->data_len; 219 data = msg->data; 220 if (message_len < 4) { 221 rc = -EIO; 222 goto out; 223 } 224 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) { 225 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n"); 226 rc = -EIO; 227 goto out; 228 } 229 if (data[i++]) { 230 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value " 231 "[%d]\n", data[i-1]); 232 rc = -EIO; 233 goto out; 234 } 235 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len); 236 if (rc) { 237 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 238 "rc = [%d]\n", rc); 239 goto out; 240 } 241 i += data_len; 242 if (message_len < (i + m_size)) { 243 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd " 244 "is shorter than expected\n"); 245 rc = -EIO; 246 goto out; 247 } 248 if (m_size < 3) { 249 ecryptfs_printk(KERN_ERR, 250 "The decrypted key is not long enough to " 251 "include a cipher code and checksum\n"); 252 rc = -EIO; 253 goto out; 254 } 255 *cipher_code = data[i++]; 256 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */ 257 session_key->decrypted_key_size = m_size - 3; 258 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) { 259 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than " 260 "the maximum key size [%d]\n", 261 session_key->decrypted_key_size, 262 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 263 rc = -EIO; 264 goto out; 265 } 266 memcpy(session_key->decrypted_key, &data[i], 267 session_key->decrypted_key_size); 268 i += session_key->decrypted_key_size; 269 expected_checksum += (unsigned char)(data[i++]) << 8; 270 expected_checksum += (unsigned char)(data[i++]); 271 for (i = 0; i < session_key->decrypted_key_size; i++) 272 checksum += session_key->decrypted_key[i]; 273 if (expected_checksum != checksum) { 274 ecryptfs_printk(KERN_ERR, "Invalid checksum for file " 275 "encryption key; expected [%x]; calculated " 276 "[%x]\n", expected_checksum, checksum); 277 rc = -EIO; 278 } 279 out: 280 return rc; 281 } 282 283 284 static int 285 write_tag_66_packet(char *signature, u8 cipher_code, 286 struct ecryptfs_crypt_stat *crypt_stat, char **packet, 287 size_t *packet_len) 288 { 289 size_t i = 0; 290 size_t j; 291 size_t data_len; 292 size_t checksum = 0; 293 size_t packet_size_len; 294 char *message; 295 int rc; 296 297 /* 298 * ***** TAG 66 Packet Format ***** 299 * | Content Type | 1 byte | 300 * | Key Identifier Size | 1 or 2 bytes | 301 * | Key Identifier | arbitrary | 302 * | File Encryption Key Size | 1 or 2 bytes | 303 * | File Encryption Key | arbitrary | 304 */ 305 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); 306 *packet = kmalloc(data_len, GFP_KERNEL); 307 message = *packet; 308 if (!message) { 309 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 310 rc = -ENOMEM; 311 goto out; 312 } 313 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; 314 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 315 &packet_size_len); 316 if (rc) { 317 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 318 "header; cannot generate packet length\n"); 319 goto out; 320 } 321 i += packet_size_len; 322 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 323 i += ECRYPTFS_SIG_SIZE_HEX; 324 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */ 325 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, 326 &packet_size_len); 327 if (rc) { 328 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 329 "header; cannot generate packet length\n"); 330 goto out; 331 } 332 i += packet_size_len; 333 message[i++] = cipher_code; 334 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); 335 i += crypt_stat->key_size; 336 for (j = 0; j < crypt_stat->key_size; j++) 337 checksum += crypt_stat->key[j]; 338 message[i++] = (checksum / 256) % 256; 339 message[i++] = (checksum % 256); 340 *packet_len = i; 341 out: 342 return rc; 343 } 344 345 static int 346 parse_tag_67_packet(struct ecryptfs_key_record *key_rec, 347 struct ecryptfs_message *msg) 348 { 349 size_t i = 0; 350 char *data; 351 size_t data_len; 352 size_t message_len; 353 int rc; 354 355 /* 356 * ***** TAG 65 Packet Format ***** 357 * | Content Type | 1 byte | 358 * | Status Indicator | 1 byte | 359 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 360 * | Encrypted File Encryption Key | arbitrary | 361 */ 362 message_len = msg->data_len; 363 data = msg->data; 364 /* verify that everything through the encrypted FEK size is present */ 365 if (message_len < 4) { 366 rc = -EIO; 367 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " 368 "message length is [%d]\n", __func__, message_len, 4); 369 goto out; 370 } 371 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { 372 rc = -EIO; 373 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", 374 __func__); 375 goto out; 376 } 377 if (data[i++]) { 378 rc = -EIO; 379 printk(KERN_ERR "%s: Status indicator has non zero " 380 "value [%d]\n", __func__, data[i-1]); 381 382 goto out; 383 } 384 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, 385 &data_len); 386 if (rc) { 387 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 388 "rc = [%d]\n", rc); 389 goto out; 390 } 391 i += data_len; 392 if (message_len < (i + key_rec->enc_key_size)) { 393 rc = -EIO; 394 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", 395 __func__, message_len, (i + key_rec->enc_key_size)); 396 goto out; 397 } 398 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 399 rc = -EIO; 400 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " 401 "the maximum key size [%d]\n", __func__, 402 key_rec->enc_key_size, 403 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 404 goto out; 405 } 406 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); 407 out: 408 return rc; 409 } 410 411 /** 412 * ecryptfs_verify_version 413 * @version: The version number to confirm 414 * 415 * Returns zero on good version; non-zero otherwise 416 */ 417 static int ecryptfs_verify_version(u16 version) 418 { 419 int rc = 0; 420 unsigned char major; 421 unsigned char minor; 422 423 major = ((version >> 8) & 0xFF); 424 minor = (version & 0xFF); 425 if (major != ECRYPTFS_VERSION_MAJOR) { 426 ecryptfs_printk(KERN_ERR, "Major version number mismatch. " 427 "Expected [%d]; got [%d]\n", 428 ECRYPTFS_VERSION_MAJOR, major); 429 rc = -EINVAL; 430 goto out; 431 } 432 if (minor != ECRYPTFS_VERSION_MINOR) { 433 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " 434 "Expected [%d]; got [%d]\n", 435 ECRYPTFS_VERSION_MINOR, minor); 436 rc = -EINVAL; 437 goto out; 438 } 439 out: 440 return rc; 441 } 442 443 /** 444 * ecryptfs_verify_auth_tok_from_key 445 * @auth_tok_key: key containing the authentication token 446 * @auth_tok: authentication token 447 * 448 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or 449 * -EKEYREVOKED if the key was revoked before we acquired its semaphore. 450 */ 451 static int 452 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, 453 struct ecryptfs_auth_tok **auth_tok) 454 { 455 int rc = 0; 456 457 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); 458 if (IS_ERR(*auth_tok)) { 459 rc = PTR_ERR(*auth_tok); 460 *auth_tok = NULL; 461 goto out; 462 } 463 464 if (ecryptfs_verify_version((*auth_tok)->version)) { 465 printk(KERN_ERR "Data structure version mismatch. Userspace " 466 "tools must match eCryptfs kernel module with major " 467 "version [%d] and minor version [%d]\n", 468 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); 469 rc = -EINVAL; 470 goto out; 471 } 472 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD 473 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { 474 printk(KERN_ERR "Invalid auth_tok structure " 475 "returned from key query\n"); 476 rc = -EINVAL; 477 goto out; 478 } 479 out: 480 return rc; 481 } 482 483 static int 484 ecryptfs_find_global_auth_tok_for_sig( 485 struct key **auth_tok_key, 486 struct ecryptfs_auth_tok **auth_tok, 487 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) 488 { 489 struct ecryptfs_global_auth_tok *walker; 490 int rc = 0; 491 492 (*auth_tok_key) = NULL; 493 (*auth_tok) = NULL; 494 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 495 list_for_each_entry(walker, 496 &mount_crypt_stat->global_auth_tok_list, 497 mount_crypt_stat_list) { 498 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) 499 continue; 500 501 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { 502 rc = -EINVAL; 503 goto out; 504 } 505 506 rc = key_validate(walker->global_auth_tok_key); 507 if (rc) { 508 if (rc == -EKEYEXPIRED) 509 goto out; 510 goto out_invalid_auth_tok; 511 } 512 513 down_write(&(walker->global_auth_tok_key->sem)); 514 rc = ecryptfs_verify_auth_tok_from_key( 515 walker->global_auth_tok_key, auth_tok); 516 if (rc) 517 goto out_invalid_auth_tok_unlock; 518 519 (*auth_tok_key) = walker->global_auth_tok_key; 520 key_get(*auth_tok_key); 521 goto out; 522 } 523 rc = -ENOENT; 524 goto out; 525 out_invalid_auth_tok_unlock: 526 up_write(&(walker->global_auth_tok_key->sem)); 527 out_invalid_auth_tok: 528 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); 529 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; 530 key_put(walker->global_auth_tok_key); 531 walker->global_auth_tok_key = NULL; 532 out: 533 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 534 return rc; 535 } 536 537 /** 538 * ecryptfs_find_auth_tok_for_sig 539 * @auth_tok: Set to the matching auth_tok; NULL if not found 540 * @crypt_stat: inode crypt_stat crypto context 541 * @sig: Sig of auth_tok to find 542 * 543 * For now, this function simply looks at the registered auth_tok's 544 * linked off the mount_crypt_stat, so all the auth_toks that can be 545 * used must be registered at mount time. This function could 546 * potentially try a lot harder to find auth_tok's (e.g., by calling 547 * out to ecryptfsd to dynamically retrieve an auth_tok object) so 548 * that static registration of auth_tok's will no longer be necessary. 549 * 550 * Returns zero on no error; non-zero on error 551 */ 552 static int 553 ecryptfs_find_auth_tok_for_sig( 554 struct key **auth_tok_key, 555 struct ecryptfs_auth_tok **auth_tok, 556 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 557 char *sig) 558 { 559 int rc = 0; 560 561 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, 562 mount_crypt_stat, sig); 563 if (rc == -ENOENT) { 564 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the 565 * mount_crypt_stat structure, we prevent to use auth toks that 566 * are not inserted through the ecryptfs_add_global_auth_tok 567 * function. 568 */ 569 if (mount_crypt_stat->flags 570 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) 571 return -EINVAL; 572 573 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, 574 sig); 575 } 576 return rc; 577 } 578 579 /** 580 * write_tag_70_packet can gobble a lot of stack space. We stuff most 581 * of the function's parameters in a kmalloc'd struct to help reduce 582 * eCryptfs' overall stack usage. 583 */ 584 struct ecryptfs_write_tag_70_packet_silly_stack { 585 u8 cipher_code; 586 size_t max_packet_size; 587 size_t packet_size_len; 588 size_t block_aligned_filename_size; 589 size_t block_size; 590 size_t i; 591 size_t j; 592 size_t num_rand_bytes; 593 struct mutex *tfm_mutex; 594 char *block_aligned_filename; 595 struct ecryptfs_auth_tok *auth_tok; 596 struct scatterlist src_sg[2]; 597 struct scatterlist dst_sg[2]; 598 struct crypto_skcipher *skcipher_tfm; 599 struct skcipher_request *skcipher_req; 600 char iv[ECRYPTFS_MAX_IV_BYTES]; 601 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 602 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 603 struct crypto_shash *hash_tfm; 604 struct shash_desc *hash_desc; 605 }; 606 607 /** 608 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK 609 * @filename: NULL-terminated filename string 610 * 611 * This is the simplest mechanism for achieving filename encryption in 612 * eCryptfs. It encrypts the given filename with the mount-wide 613 * filename encryption key (FNEK) and stores it in a packet to @dest, 614 * which the callee will encode and write directly into the dentry 615 * name. 616 */ 617 int 618 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, 619 size_t *packet_size, 620 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 621 char *filename, size_t filename_size) 622 { 623 struct ecryptfs_write_tag_70_packet_silly_stack *s; 624 struct key *auth_tok_key = NULL; 625 int rc = 0; 626 627 s = kzalloc(sizeof(*s), GFP_KERNEL); 628 if (!s) 629 return -ENOMEM; 630 631 (*packet_size) = 0; 632 rc = ecryptfs_find_auth_tok_for_sig( 633 &auth_tok_key, 634 &s->auth_tok, mount_crypt_stat, 635 mount_crypt_stat->global_default_fnek_sig); 636 if (rc) { 637 printk(KERN_ERR "%s: Error attempting to find auth tok for " 638 "fnek sig [%s]; rc = [%d]\n", __func__, 639 mount_crypt_stat->global_default_fnek_sig, rc); 640 goto out; 641 } 642 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 643 &s->skcipher_tfm, 644 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 645 if (unlikely(rc)) { 646 printk(KERN_ERR "Internal error whilst attempting to get " 647 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 648 mount_crypt_stat->global_default_fn_cipher_name, rc); 649 goto out; 650 } 651 mutex_lock(s->tfm_mutex); 652 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm); 653 /* Plus one for the \0 separator between the random prefix 654 * and the plaintext filename */ 655 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 656 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 657 if ((s->block_aligned_filename_size % s->block_size) != 0) { 658 s->num_rand_bytes += (s->block_size 659 - (s->block_aligned_filename_size 660 % s->block_size)); 661 s->block_aligned_filename_size = (s->num_rand_bytes 662 + filename_size); 663 } 664 /* Octet 0: Tag 70 identifier 665 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 666 * and block-aligned encrypted filename size) 667 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 668 * Octet N2-N3: Cipher identifier (1 octet) 669 * Octets N3-N4: Block-aligned encrypted filename 670 * - Consists of a minimum number of random characters, a \0 671 * separator, and then the filename */ 672 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 673 + s->block_aligned_filename_size); 674 if (!dest) { 675 (*packet_size) = s->max_packet_size; 676 goto out_unlock; 677 } 678 if (s->max_packet_size > (*remaining_bytes)) { 679 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 680 "[%zd] available\n", __func__, s->max_packet_size, 681 (*remaining_bytes)); 682 rc = -EINVAL; 683 goto out_unlock; 684 } 685 686 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 687 if (!s->skcipher_req) { 688 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 689 "skcipher_request_alloc for %s\n", __func__, 690 crypto_skcipher_driver_name(s->skcipher_tfm)); 691 rc = -ENOMEM; 692 goto out_unlock; 693 } 694 695 skcipher_request_set_callback(s->skcipher_req, 696 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 697 698 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 699 GFP_KERNEL); 700 if (!s->block_aligned_filename) { 701 rc = -ENOMEM; 702 goto out_unlock; 703 } 704 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 705 rc = ecryptfs_write_packet_length(&dest[s->i], 706 (ECRYPTFS_SIG_SIZE 707 + 1 /* Cipher code */ 708 + s->block_aligned_filename_size), 709 &s->packet_size_len); 710 if (rc) { 711 printk(KERN_ERR "%s: Error generating tag 70 packet " 712 "header; cannot generate packet length; rc = [%d]\n", 713 __func__, rc); 714 goto out_free_unlock; 715 } 716 s->i += s->packet_size_len; 717 ecryptfs_from_hex(&dest[s->i], 718 mount_crypt_stat->global_default_fnek_sig, 719 ECRYPTFS_SIG_SIZE); 720 s->i += ECRYPTFS_SIG_SIZE; 721 s->cipher_code = ecryptfs_code_for_cipher_string( 722 mount_crypt_stat->global_default_fn_cipher_name, 723 mount_crypt_stat->global_default_fn_cipher_key_bytes); 724 if (s->cipher_code == 0) { 725 printk(KERN_WARNING "%s: Unable to generate code for " 726 "cipher [%s] with key bytes [%zd]\n", __func__, 727 mount_crypt_stat->global_default_fn_cipher_name, 728 mount_crypt_stat->global_default_fn_cipher_key_bytes); 729 rc = -EINVAL; 730 goto out_free_unlock; 731 } 732 dest[s->i++] = s->cipher_code; 733 /* TODO: Support other key modules than passphrase for 734 * filename encryption */ 735 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 736 rc = -EOPNOTSUPP; 737 printk(KERN_INFO "%s: Filename encryption only supports " 738 "password tokens\n", __func__); 739 goto out_free_unlock; 740 } 741 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0); 742 if (IS_ERR(s->hash_tfm)) { 743 rc = PTR_ERR(s->hash_tfm); 744 printk(KERN_ERR "%s: Error attempting to " 745 "allocate hash crypto context; rc = [%d]\n", 746 __func__, rc); 747 goto out_free_unlock; 748 } 749 750 s->hash_desc = kmalloc(sizeof(*s->hash_desc) + 751 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL); 752 if (!s->hash_desc) { 753 rc = -ENOMEM; 754 goto out_release_free_unlock; 755 } 756 757 s->hash_desc->tfm = s->hash_tfm; 758 759 rc = crypto_shash_digest(s->hash_desc, 760 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 761 s->auth_tok->token.password.session_key_encryption_key_bytes, 762 s->hash); 763 if (rc) { 764 printk(KERN_ERR 765 "%s: Error computing crypto hash; rc = [%d]\n", 766 __func__, rc); 767 goto out_release_free_unlock; 768 } 769 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 770 s->block_aligned_filename[s->j] = 771 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 772 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 773 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 774 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash, 775 ECRYPTFS_TAG_70_DIGEST_SIZE, 776 s->tmp_hash); 777 if (rc) { 778 printk(KERN_ERR 779 "%s: Error computing crypto hash; " 780 "rc = [%d]\n", __func__, rc); 781 goto out_release_free_unlock; 782 } 783 memcpy(s->hash, s->tmp_hash, 784 ECRYPTFS_TAG_70_DIGEST_SIZE); 785 } 786 if (s->block_aligned_filename[s->j] == '\0') 787 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 788 } 789 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 790 filename_size); 791 rc = virt_to_scatterlist(s->block_aligned_filename, 792 s->block_aligned_filename_size, s->src_sg, 2); 793 if (rc < 1) { 794 printk(KERN_ERR "%s: Internal error whilst attempting to " 795 "convert filename memory to scatterlist; rc = [%d]. " 796 "block_aligned_filename_size = [%zd]\n", __func__, rc, 797 s->block_aligned_filename_size); 798 goto out_release_free_unlock; 799 } 800 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 801 s->dst_sg, 2); 802 if (rc < 1) { 803 printk(KERN_ERR "%s: Internal error whilst attempting to " 804 "convert encrypted filename memory to scatterlist; " 805 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 806 __func__, rc, s->block_aligned_filename_size); 807 goto out_release_free_unlock; 808 } 809 /* The characters in the first block effectively do the job 810 * of the IV here, so we just use 0's for the IV. Note the 811 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 812 * >= ECRYPTFS_MAX_IV_BYTES. */ 813 rc = crypto_skcipher_setkey( 814 s->skcipher_tfm, 815 s->auth_tok->token.password.session_key_encryption_key, 816 mount_crypt_stat->global_default_fn_cipher_key_bytes); 817 if (rc < 0) { 818 printk(KERN_ERR "%s: Error setting key for crypto context; " 819 "rc = [%d]. s->auth_tok->token.password.session_key_" 820 "encryption_key = [0x%p]; mount_crypt_stat->" 821 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 822 rc, 823 s->auth_tok->token.password.session_key_encryption_key, 824 mount_crypt_stat->global_default_fn_cipher_key_bytes); 825 goto out_release_free_unlock; 826 } 827 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 828 s->block_aligned_filename_size, s->iv); 829 rc = crypto_skcipher_encrypt(s->skcipher_req); 830 if (rc) { 831 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 832 "rc = [%d]\n", __func__, rc); 833 goto out_release_free_unlock; 834 } 835 s->i += s->block_aligned_filename_size; 836 (*packet_size) = s->i; 837 (*remaining_bytes) -= (*packet_size); 838 out_release_free_unlock: 839 crypto_free_shash(s->hash_tfm); 840 out_free_unlock: 841 kzfree(s->block_aligned_filename); 842 out_unlock: 843 mutex_unlock(s->tfm_mutex); 844 out: 845 if (auth_tok_key) { 846 up_write(&(auth_tok_key->sem)); 847 key_put(auth_tok_key); 848 } 849 skcipher_request_free(s->skcipher_req); 850 kzfree(s->hash_desc); 851 kfree(s); 852 return rc; 853 } 854 855 struct ecryptfs_parse_tag_70_packet_silly_stack { 856 u8 cipher_code; 857 size_t max_packet_size; 858 size_t packet_size_len; 859 size_t parsed_tag_70_packet_size; 860 size_t block_aligned_filename_size; 861 size_t block_size; 862 size_t i; 863 struct mutex *tfm_mutex; 864 char *decrypted_filename; 865 struct ecryptfs_auth_tok *auth_tok; 866 struct scatterlist src_sg[2]; 867 struct scatterlist dst_sg[2]; 868 struct crypto_skcipher *skcipher_tfm; 869 struct skcipher_request *skcipher_req; 870 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 871 char iv[ECRYPTFS_MAX_IV_BYTES]; 872 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; 873 }; 874 875 /** 876 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 877 * @filename: This function kmalloc's the memory for the filename 878 * @filename_size: This function sets this to the amount of memory 879 * kmalloc'd for the filename 880 * @packet_size: This function sets this to the the number of octets 881 * in the packet parsed 882 * @mount_crypt_stat: The mount-wide cryptographic context 883 * @data: The memory location containing the start of the tag 70 884 * packet 885 * @max_packet_size: The maximum legal size of the packet to be parsed 886 * from @data 887 * 888 * Returns zero on success; non-zero otherwise 889 */ 890 int 891 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 892 size_t *packet_size, 893 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 894 char *data, size_t max_packet_size) 895 { 896 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 897 struct key *auth_tok_key = NULL; 898 int rc = 0; 899 900 (*packet_size) = 0; 901 (*filename_size) = 0; 902 (*filename) = NULL; 903 s = kzalloc(sizeof(*s), GFP_KERNEL); 904 if (!s) 905 return -ENOMEM; 906 907 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 908 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 909 "at least [%d]\n", __func__, max_packet_size, 910 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 911 rc = -EINVAL; 912 goto out; 913 } 914 /* Octet 0: Tag 70 identifier 915 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 916 * and block-aligned encrypted filename size) 917 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 918 * Octet N2-N3: Cipher identifier (1 octet) 919 * Octets N3-N4: Block-aligned encrypted filename 920 * - Consists of a minimum number of random numbers, a \0 921 * separator, and then the filename */ 922 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 923 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 924 "tag [0x%.2x]\n", __func__, 925 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 926 rc = -EINVAL; 927 goto out; 928 } 929 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 930 &s->parsed_tag_70_packet_size, 931 &s->packet_size_len); 932 if (rc) { 933 printk(KERN_WARNING "%s: Error parsing packet length; " 934 "rc = [%d]\n", __func__, rc); 935 goto out; 936 } 937 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 938 - ECRYPTFS_SIG_SIZE - 1); 939 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 940 > max_packet_size) { 941 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 942 "size is [%zd]\n", __func__, max_packet_size, 943 (1 + s->packet_size_len + 1 944 + s->block_aligned_filename_size)); 945 rc = -EINVAL; 946 goto out; 947 } 948 (*packet_size) += s->packet_size_len; 949 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 950 ECRYPTFS_SIG_SIZE); 951 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 952 (*packet_size) += ECRYPTFS_SIG_SIZE; 953 s->cipher_code = data[(*packet_size)++]; 954 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 955 if (rc) { 956 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 957 __func__, s->cipher_code); 958 goto out; 959 } 960 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 961 &s->auth_tok, mount_crypt_stat, 962 s->fnek_sig_hex); 963 if (rc) { 964 printk(KERN_ERR "%s: Error attempting to find auth tok for " 965 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 966 rc); 967 goto out; 968 } 969 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm, 970 &s->tfm_mutex, 971 s->cipher_string); 972 if (unlikely(rc)) { 973 printk(KERN_ERR "Internal error whilst attempting to get " 974 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 975 s->cipher_string, rc); 976 goto out; 977 } 978 mutex_lock(s->tfm_mutex); 979 rc = virt_to_scatterlist(&data[(*packet_size)], 980 s->block_aligned_filename_size, s->src_sg, 2); 981 if (rc < 1) { 982 printk(KERN_ERR "%s: Internal error whilst attempting to " 983 "convert encrypted filename memory to scatterlist; " 984 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 985 __func__, rc, s->block_aligned_filename_size); 986 goto out_unlock; 987 } 988 (*packet_size) += s->block_aligned_filename_size; 989 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 990 GFP_KERNEL); 991 if (!s->decrypted_filename) { 992 rc = -ENOMEM; 993 goto out_unlock; 994 } 995 rc = virt_to_scatterlist(s->decrypted_filename, 996 s->block_aligned_filename_size, s->dst_sg, 2); 997 if (rc < 1) { 998 printk(KERN_ERR "%s: Internal error whilst attempting to " 999 "convert decrypted filename memory to scatterlist; " 1000 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1001 __func__, rc, s->block_aligned_filename_size); 1002 goto out_free_unlock; 1003 } 1004 1005 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 1006 if (!s->skcipher_req) { 1007 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1008 "skcipher_request_alloc for %s\n", __func__, 1009 crypto_skcipher_driver_name(s->skcipher_tfm)); 1010 rc = -ENOMEM; 1011 goto out_free_unlock; 1012 } 1013 1014 skcipher_request_set_callback(s->skcipher_req, 1015 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 1016 1017 /* The characters in the first block effectively do the job of 1018 * the IV here, so we just use 0's for the IV. Note the 1019 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1020 * >= ECRYPTFS_MAX_IV_BYTES. */ 1021 /* TODO: Support other key modules than passphrase for 1022 * filename encryption */ 1023 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1024 rc = -EOPNOTSUPP; 1025 printk(KERN_INFO "%s: Filename encryption only supports " 1026 "password tokens\n", __func__); 1027 goto out_free_unlock; 1028 } 1029 rc = crypto_skcipher_setkey( 1030 s->skcipher_tfm, 1031 s->auth_tok->token.password.session_key_encryption_key, 1032 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1033 if (rc < 0) { 1034 printk(KERN_ERR "%s: Error setting key for crypto context; " 1035 "rc = [%d]. s->auth_tok->token.password.session_key_" 1036 "encryption_key = [0x%p]; mount_crypt_stat->" 1037 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1038 rc, 1039 s->auth_tok->token.password.session_key_encryption_key, 1040 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1041 goto out_free_unlock; 1042 } 1043 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 1044 s->block_aligned_filename_size, s->iv); 1045 rc = crypto_skcipher_decrypt(s->skcipher_req); 1046 if (rc) { 1047 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1048 "rc = [%d]\n", __func__, rc); 1049 goto out_free_unlock; 1050 } 1051 while (s->decrypted_filename[s->i] != '\0' 1052 && s->i < s->block_aligned_filename_size) 1053 s->i++; 1054 if (s->i == s->block_aligned_filename_size) { 1055 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1056 "find valid separator between random characters and " 1057 "the filename\n", __func__); 1058 rc = -EINVAL; 1059 goto out_free_unlock; 1060 } 1061 s->i++; 1062 (*filename_size) = (s->block_aligned_filename_size - s->i); 1063 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1064 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1065 "invalid\n", __func__, (*filename_size)); 1066 rc = -EINVAL; 1067 goto out_free_unlock; 1068 } 1069 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1070 if (!(*filename)) { 1071 rc = -ENOMEM; 1072 goto out_free_unlock; 1073 } 1074 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1075 (*filename)[(*filename_size)] = '\0'; 1076 out_free_unlock: 1077 kfree(s->decrypted_filename); 1078 out_unlock: 1079 mutex_unlock(s->tfm_mutex); 1080 out: 1081 if (rc) { 1082 (*packet_size) = 0; 1083 (*filename_size) = 0; 1084 (*filename) = NULL; 1085 } 1086 if (auth_tok_key) { 1087 up_write(&(auth_tok_key->sem)); 1088 key_put(auth_tok_key); 1089 } 1090 skcipher_request_free(s->skcipher_req); 1091 kfree(s); 1092 return rc; 1093 } 1094 1095 static int 1096 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1097 { 1098 int rc = 0; 1099 1100 (*sig) = NULL; 1101 switch (auth_tok->token_type) { 1102 case ECRYPTFS_PASSWORD: 1103 (*sig) = auth_tok->token.password.signature; 1104 break; 1105 case ECRYPTFS_PRIVATE_KEY: 1106 (*sig) = auth_tok->token.private_key.signature; 1107 break; 1108 default: 1109 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1110 auth_tok->token_type); 1111 rc = -EINVAL; 1112 } 1113 return rc; 1114 } 1115 1116 /** 1117 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1118 * @auth_tok: The key authentication token used to decrypt the session key 1119 * @crypt_stat: The cryptographic context 1120 * 1121 * Returns zero on success; non-zero error otherwise. 1122 */ 1123 static int 1124 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1125 struct ecryptfs_crypt_stat *crypt_stat) 1126 { 1127 u8 cipher_code = 0; 1128 struct ecryptfs_msg_ctx *msg_ctx; 1129 struct ecryptfs_message *msg = NULL; 1130 char *auth_tok_sig; 1131 char *payload = NULL; 1132 size_t payload_len = 0; 1133 int rc; 1134 1135 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1136 if (rc) { 1137 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1138 auth_tok->token_type); 1139 goto out; 1140 } 1141 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1142 &payload, &payload_len); 1143 if (rc) { 1144 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1145 goto out; 1146 } 1147 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1148 if (rc) { 1149 ecryptfs_printk(KERN_ERR, "Error sending message to " 1150 "ecryptfsd: %d\n", rc); 1151 goto out; 1152 } 1153 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1154 if (rc) { 1155 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1156 "from the user space daemon\n"); 1157 rc = -EIO; 1158 goto out; 1159 } 1160 rc = parse_tag_65_packet(&(auth_tok->session_key), 1161 &cipher_code, msg); 1162 if (rc) { 1163 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1164 rc); 1165 goto out; 1166 } 1167 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1168 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1169 auth_tok->session_key.decrypted_key_size); 1170 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1171 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1172 if (rc) { 1173 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1174 cipher_code) 1175 goto out; 1176 } 1177 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1178 if (ecryptfs_verbosity > 0) { 1179 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1180 ecryptfs_dump_hex(crypt_stat->key, 1181 crypt_stat->key_size); 1182 } 1183 out: 1184 kfree(msg); 1185 kfree(payload); 1186 return rc; 1187 } 1188 1189 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1190 { 1191 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1192 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1193 1194 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1195 auth_tok_list_head, list) { 1196 list_del(&auth_tok_list_item->list); 1197 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1198 auth_tok_list_item); 1199 } 1200 } 1201 1202 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1203 1204 /** 1205 * parse_tag_1_packet 1206 * @crypt_stat: The cryptographic context to modify based on packet contents 1207 * @data: The raw bytes of the packet. 1208 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1209 * a new authentication token will be placed at the 1210 * end of this list for this packet. 1211 * @new_auth_tok: Pointer to a pointer to memory that this function 1212 * allocates; sets the memory address of the pointer to 1213 * NULL on error. This object is added to the 1214 * auth_tok_list. 1215 * @packet_size: This function writes the size of the parsed packet 1216 * into this memory location; zero on error. 1217 * @max_packet_size: The maximum allowable packet size 1218 * 1219 * Returns zero on success; non-zero on error. 1220 */ 1221 static int 1222 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1223 unsigned char *data, struct list_head *auth_tok_list, 1224 struct ecryptfs_auth_tok **new_auth_tok, 1225 size_t *packet_size, size_t max_packet_size) 1226 { 1227 size_t body_size; 1228 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1229 size_t length_size; 1230 int rc = 0; 1231 1232 (*packet_size) = 0; 1233 (*new_auth_tok) = NULL; 1234 /** 1235 * This format is inspired by OpenPGP; see RFC 2440 1236 * packet tag 1 1237 * 1238 * Tag 1 identifier (1 byte) 1239 * Max Tag 1 packet size (max 3 bytes) 1240 * Version (1 byte) 1241 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1242 * Cipher identifier (1 byte) 1243 * Encrypted key size (arbitrary) 1244 * 1245 * 12 bytes minimum packet size 1246 */ 1247 if (unlikely(max_packet_size < 12)) { 1248 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1249 rc = -EINVAL; 1250 goto out; 1251 } 1252 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1253 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1254 ECRYPTFS_TAG_1_PACKET_TYPE); 1255 rc = -EINVAL; 1256 goto out; 1257 } 1258 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1259 * at end of function upon failure */ 1260 auth_tok_list_item = 1261 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1262 GFP_KERNEL); 1263 if (!auth_tok_list_item) { 1264 printk(KERN_ERR "Unable to allocate memory\n"); 1265 rc = -ENOMEM; 1266 goto out; 1267 } 1268 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1269 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1270 &length_size); 1271 if (rc) { 1272 printk(KERN_WARNING "Error parsing packet length; " 1273 "rc = [%d]\n", rc); 1274 goto out_free; 1275 } 1276 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1277 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1278 rc = -EINVAL; 1279 goto out_free; 1280 } 1281 (*packet_size) += length_size; 1282 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1283 printk(KERN_WARNING "Packet size exceeds max\n"); 1284 rc = -EINVAL; 1285 goto out_free; 1286 } 1287 if (unlikely(data[(*packet_size)++] != 0x03)) { 1288 printk(KERN_WARNING "Unknown version number [%d]\n", 1289 data[(*packet_size) - 1]); 1290 rc = -EINVAL; 1291 goto out_free; 1292 } 1293 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1294 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1295 *packet_size += ECRYPTFS_SIG_SIZE; 1296 /* This byte is skipped because the kernel does not need to 1297 * know which public key encryption algorithm was used */ 1298 (*packet_size)++; 1299 (*new_auth_tok)->session_key.encrypted_key_size = 1300 body_size - (ECRYPTFS_SIG_SIZE + 2); 1301 if ((*new_auth_tok)->session_key.encrypted_key_size 1302 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1303 printk(KERN_WARNING "Tag 1 packet contains key larger " 1304 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1305 rc = -EINVAL; 1306 goto out; 1307 } 1308 memcpy((*new_auth_tok)->session_key.encrypted_key, 1309 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1310 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1311 (*new_auth_tok)->session_key.flags &= 1312 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1313 (*new_auth_tok)->session_key.flags |= 1314 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1315 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1316 (*new_auth_tok)->flags = 0; 1317 (*new_auth_tok)->session_key.flags &= 1318 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1319 (*new_auth_tok)->session_key.flags &= 1320 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1321 list_add(&auth_tok_list_item->list, auth_tok_list); 1322 goto out; 1323 out_free: 1324 (*new_auth_tok) = NULL; 1325 memset(auth_tok_list_item, 0, 1326 sizeof(struct ecryptfs_auth_tok_list_item)); 1327 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1328 auth_tok_list_item); 1329 out: 1330 if (rc) 1331 (*packet_size) = 0; 1332 return rc; 1333 } 1334 1335 /** 1336 * parse_tag_3_packet 1337 * @crypt_stat: The cryptographic context to modify based on packet 1338 * contents. 1339 * @data: The raw bytes of the packet. 1340 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1341 * a new authentication token will be placed at the end 1342 * of this list for this packet. 1343 * @new_auth_tok: Pointer to a pointer to memory that this function 1344 * allocates; sets the memory address of the pointer to 1345 * NULL on error. This object is added to the 1346 * auth_tok_list. 1347 * @packet_size: This function writes the size of the parsed packet 1348 * into this memory location; zero on error. 1349 * @max_packet_size: maximum number of bytes to parse 1350 * 1351 * Returns zero on success; non-zero on error. 1352 */ 1353 static int 1354 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1355 unsigned char *data, struct list_head *auth_tok_list, 1356 struct ecryptfs_auth_tok **new_auth_tok, 1357 size_t *packet_size, size_t max_packet_size) 1358 { 1359 size_t body_size; 1360 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1361 size_t length_size; 1362 int rc = 0; 1363 1364 (*packet_size) = 0; 1365 (*new_auth_tok) = NULL; 1366 /** 1367 *This format is inspired by OpenPGP; see RFC 2440 1368 * packet tag 3 1369 * 1370 * Tag 3 identifier (1 byte) 1371 * Max Tag 3 packet size (max 3 bytes) 1372 * Version (1 byte) 1373 * Cipher code (1 byte) 1374 * S2K specifier (1 byte) 1375 * Hash identifier (1 byte) 1376 * Salt (ECRYPTFS_SALT_SIZE) 1377 * Hash iterations (1 byte) 1378 * Encrypted key (arbitrary) 1379 * 1380 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1381 */ 1382 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1383 printk(KERN_ERR "Max packet size too large\n"); 1384 rc = -EINVAL; 1385 goto out; 1386 } 1387 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1388 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1389 ECRYPTFS_TAG_3_PACKET_TYPE); 1390 rc = -EINVAL; 1391 goto out; 1392 } 1393 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1394 * at end of function upon failure */ 1395 auth_tok_list_item = 1396 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1397 if (!auth_tok_list_item) { 1398 printk(KERN_ERR "Unable to allocate memory\n"); 1399 rc = -ENOMEM; 1400 goto out; 1401 } 1402 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1403 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1404 &length_size); 1405 if (rc) { 1406 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1407 rc); 1408 goto out_free; 1409 } 1410 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1411 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1412 rc = -EINVAL; 1413 goto out_free; 1414 } 1415 (*packet_size) += length_size; 1416 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1417 printk(KERN_ERR "Packet size exceeds max\n"); 1418 rc = -EINVAL; 1419 goto out_free; 1420 } 1421 (*new_auth_tok)->session_key.encrypted_key_size = 1422 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1423 if ((*new_auth_tok)->session_key.encrypted_key_size 1424 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1425 printk(KERN_WARNING "Tag 3 packet contains key larger " 1426 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1427 rc = -EINVAL; 1428 goto out_free; 1429 } 1430 if (unlikely(data[(*packet_size)++] != 0x04)) { 1431 printk(KERN_WARNING "Unknown version number [%d]\n", 1432 data[(*packet_size) - 1]); 1433 rc = -EINVAL; 1434 goto out_free; 1435 } 1436 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1437 (u16)data[(*packet_size)]); 1438 if (rc) 1439 goto out_free; 1440 /* A little extra work to differentiate among the AES key 1441 * sizes; see RFC2440 */ 1442 switch(data[(*packet_size)++]) { 1443 case RFC2440_CIPHER_AES_192: 1444 crypt_stat->key_size = 24; 1445 break; 1446 default: 1447 crypt_stat->key_size = 1448 (*new_auth_tok)->session_key.encrypted_key_size; 1449 } 1450 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1451 if (rc) 1452 goto out_free; 1453 if (unlikely(data[(*packet_size)++] != 0x03)) { 1454 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1455 rc = -ENOSYS; 1456 goto out_free; 1457 } 1458 /* TODO: finish the hash mapping */ 1459 switch (data[(*packet_size)++]) { 1460 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1461 /* Choose MD5 */ 1462 memcpy((*new_auth_tok)->token.password.salt, 1463 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1464 (*packet_size) += ECRYPTFS_SALT_SIZE; 1465 /* This conversion was taken straight from RFC2440 */ 1466 (*new_auth_tok)->token.password.hash_iterations = 1467 ((u32) 16 + (data[(*packet_size)] & 15)) 1468 << ((data[(*packet_size)] >> 4) + 6); 1469 (*packet_size)++; 1470 /* Friendly reminder: 1471 * (*new_auth_tok)->session_key.encrypted_key_size = 1472 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1473 memcpy((*new_auth_tok)->session_key.encrypted_key, 1474 &data[(*packet_size)], 1475 (*new_auth_tok)->session_key.encrypted_key_size); 1476 (*packet_size) += 1477 (*new_auth_tok)->session_key.encrypted_key_size; 1478 (*new_auth_tok)->session_key.flags &= 1479 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1480 (*new_auth_tok)->session_key.flags |= 1481 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1482 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1483 break; 1484 default: 1485 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1486 "[%d]\n", data[(*packet_size) - 1]); 1487 rc = -ENOSYS; 1488 goto out_free; 1489 } 1490 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1491 /* TODO: Parametarize; we might actually want userspace to 1492 * decrypt the session key. */ 1493 (*new_auth_tok)->session_key.flags &= 1494 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1495 (*new_auth_tok)->session_key.flags &= 1496 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1497 list_add(&auth_tok_list_item->list, auth_tok_list); 1498 goto out; 1499 out_free: 1500 (*new_auth_tok) = NULL; 1501 memset(auth_tok_list_item, 0, 1502 sizeof(struct ecryptfs_auth_tok_list_item)); 1503 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1504 auth_tok_list_item); 1505 out: 1506 if (rc) 1507 (*packet_size) = 0; 1508 return rc; 1509 } 1510 1511 /** 1512 * parse_tag_11_packet 1513 * @data: The raw bytes of the packet 1514 * @contents: This function writes the data contents of the literal 1515 * packet into this memory location 1516 * @max_contents_bytes: The maximum number of bytes that this function 1517 * is allowed to write into contents 1518 * @tag_11_contents_size: This function writes the size of the parsed 1519 * contents into this memory location; zero on 1520 * error 1521 * @packet_size: This function writes the size of the parsed packet 1522 * into this memory location; zero on error 1523 * @max_packet_size: maximum number of bytes to parse 1524 * 1525 * Returns zero on success; non-zero on error. 1526 */ 1527 static int 1528 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1529 size_t max_contents_bytes, size_t *tag_11_contents_size, 1530 size_t *packet_size, size_t max_packet_size) 1531 { 1532 size_t body_size; 1533 size_t length_size; 1534 int rc = 0; 1535 1536 (*packet_size) = 0; 1537 (*tag_11_contents_size) = 0; 1538 /* This format is inspired by OpenPGP; see RFC 2440 1539 * packet tag 11 1540 * 1541 * Tag 11 identifier (1 byte) 1542 * Max Tag 11 packet size (max 3 bytes) 1543 * Binary format specifier (1 byte) 1544 * Filename length (1 byte) 1545 * Filename ("_CONSOLE") (8 bytes) 1546 * Modification date (4 bytes) 1547 * Literal data (arbitrary) 1548 * 1549 * We need at least 16 bytes of data for the packet to even be 1550 * valid. 1551 */ 1552 if (max_packet_size < 16) { 1553 printk(KERN_ERR "Maximum packet size too small\n"); 1554 rc = -EINVAL; 1555 goto out; 1556 } 1557 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1558 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1559 rc = -EINVAL; 1560 goto out; 1561 } 1562 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1563 &length_size); 1564 if (rc) { 1565 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1566 goto out; 1567 } 1568 if (body_size < 14) { 1569 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1570 rc = -EINVAL; 1571 goto out; 1572 } 1573 (*packet_size) += length_size; 1574 (*tag_11_contents_size) = (body_size - 14); 1575 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1576 printk(KERN_ERR "Packet size exceeds max\n"); 1577 rc = -EINVAL; 1578 goto out; 1579 } 1580 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1581 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1582 "expected size\n"); 1583 rc = -EINVAL; 1584 goto out; 1585 } 1586 if (data[(*packet_size)++] != 0x62) { 1587 printk(KERN_WARNING "Unrecognizable packet\n"); 1588 rc = -EINVAL; 1589 goto out; 1590 } 1591 if (data[(*packet_size)++] != 0x08) { 1592 printk(KERN_WARNING "Unrecognizable packet\n"); 1593 rc = -EINVAL; 1594 goto out; 1595 } 1596 (*packet_size) += 12; /* Ignore filename and modification date */ 1597 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1598 (*packet_size) += (*tag_11_contents_size); 1599 out: 1600 if (rc) { 1601 (*packet_size) = 0; 1602 (*tag_11_contents_size) = 0; 1603 } 1604 return rc; 1605 } 1606 1607 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1608 struct ecryptfs_auth_tok **auth_tok, 1609 char *sig) 1610 { 1611 int rc = 0; 1612 1613 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1614 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1615 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1616 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1617 printk(KERN_ERR "Could not find key with description: [%s]\n", 1618 sig); 1619 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1620 (*auth_tok_key) = NULL; 1621 goto out; 1622 } 1623 } 1624 down_write(&(*auth_tok_key)->sem); 1625 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1626 if (rc) { 1627 up_write(&(*auth_tok_key)->sem); 1628 key_put(*auth_tok_key); 1629 (*auth_tok_key) = NULL; 1630 goto out; 1631 } 1632 out: 1633 return rc; 1634 } 1635 1636 /** 1637 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1638 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1639 * @crypt_stat: The cryptographic context 1640 * 1641 * Returns zero on success; non-zero error otherwise 1642 */ 1643 static int 1644 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1645 struct ecryptfs_crypt_stat *crypt_stat) 1646 { 1647 struct scatterlist dst_sg[2]; 1648 struct scatterlist src_sg[2]; 1649 struct mutex *tfm_mutex; 1650 struct crypto_skcipher *tfm; 1651 struct skcipher_request *req = NULL; 1652 int rc = 0; 1653 1654 if (unlikely(ecryptfs_verbosity > 0)) { 1655 ecryptfs_printk( 1656 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1657 auth_tok->token.password.session_key_encryption_key_bytes); 1658 ecryptfs_dump_hex( 1659 auth_tok->token.password.session_key_encryption_key, 1660 auth_tok->token.password.session_key_encryption_key_bytes); 1661 } 1662 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 1663 crypt_stat->cipher); 1664 if (unlikely(rc)) { 1665 printk(KERN_ERR "Internal error whilst attempting to get " 1666 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1667 crypt_stat->cipher, rc); 1668 goto out; 1669 } 1670 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1671 auth_tok->session_key.encrypted_key_size, 1672 src_sg, 2); 1673 if (rc < 1 || rc > 2) { 1674 printk(KERN_ERR "Internal error whilst attempting to convert " 1675 "auth_tok->session_key.encrypted_key to scatterlist; " 1676 "expected rc = 1; got rc = [%d]. " 1677 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1678 auth_tok->session_key.encrypted_key_size); 1679 goto out; 1680 } 1681 auth_tok->session_key.decrypted_key_size = 1682 auth_tok->session_key.encrypted_key_size; 1683 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1684 auth_tok->session_key.decrypted_key_size, 1685 dst_sg, 2); 1686 if (rc < 1 || rc > 2) { 1687 printk(KERN_ERR "Internal error whilst attempting to convert " 1688 "auth_tok->session_key.decrypted_key to scatterlist; " 1689 "expected rc = 1; got rc = [%d]\n", rc); 1690 goto out; 1691 } 1692 mutex_lock(tfm_mutex); 1693 req = skcipher_request_alloc(tfm, GFP_KERNEL); 1694 if (!req) { 1695 mutex_unlock(tfm_mutex); 1696 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1697 "skcipher_request_alloc for %s\n", __func__, 1698 crypto_skcipher_driver_name(tfm)); 1699 rc = -ENOMEM; 1700 goto out; 1701 } 1702 1703 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 1704 NULL, NULL); 1705 rc = crypto_skcipher_setkey( 1706 tfm, auth_tok->token.password.session_key_encryption_key, 1707 crypt_stat->key_size); 1708 if (unlikely(rc < 0)) { 1709 mutex_unlock(tfm_mutex); 1710 printk(KERN_ERR "Error setting key for crypto context\n"); 1711 rc = -EINVAL; 1712 goto out; 1713 } 1714 skcipher_request_set_crypt(req, src_sg, dst_sg, 1715 auth_tok->session_key.encrypted_key_size, 1716 NULL); 1717 rc = crypto_skcipher_decrypt(req); 1718 mutex_unlock(tfm_mutex); 1719 if (unlikely(rc)) { 1720 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1721 goto out; 1722 } 1723 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1724 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1725 auth_tok->session_key.decrypted_key_size); 1726 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1727 if (unlikely(ecryptfs_verbosity > 0)) { 1728 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1729 crypt_stat->key_size); 1730 ecryptfs_dump_hex(crypt_stat->key, 1731 crypt_stat->key_size); 1732 } 1733 out: 1734 skcipher_request_free(req); 1735 return rc; 1736 } 1737 1738 /** 1739 * ecryptfs_parse_packet_set 1740 * @crypt_stat: The cryptographic context 1741 * @src: Virtual address of region of memory containing the packets 1742 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1743 * 1744 * Get crypt_stat to have the file's session key if the requisite key 1745 * is available to decrypt the session key. 1746 * 1747 * Returns Zero if a valid authentication token was retrieved and 1748 * processed; negative value for file not encrypted or for error 1749 * conditions. 1750 */ 1751 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1752 unsigned char *src, 1753 struct dentry *ecryptfs_dentry) 1754 { 1755 size_t i = 0; 1756 size_t found_auth_tok; 1757 size_t next_packet_is_auth_tok_packet; 1758 struct list_head auth_tok_list; 1759 struct ecryptfs_auth_tok *matching_auth_tok; 1760 struct ecryptfs_auth_tok *candidate_auth_tok; 1761 char *candidate_auth_tok_sig; 1762 size_t packet_size; 1763 struct ecryptfs_auth_tok *new_auth_tok; 1764 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1765 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1766 size_t tag_11_contents_size; 1767 size_t tag_11_packet_size; 1768 struct key *auth_tok_key = NULL; 1769 int rc = 0; 1770 1771 INIT_LIST_HEAD(&auth_tok_list); 1772 /* Parse the header to find as many packets as we can; these will be 1773 * added the our &auth_tok_list */ 1774 next_packet_is_auth_tok_packet = 1; 1775 while (next_packet_is_auth_tok_packet) { 1776 size_t max_packet_size = ((PAGE_SIZE - 8) - i); 1777 1778 switch (src[i]) { 1779 case ECRYPTFS_TAG_3_PACKET_TYPE: 1780 rc = parse_tag_3_packet(crypt_stat, 1781 (unsigned char *)&src[i], 1782 &auth_tok_list, &new_auth_tok, 1783 &packet_size, max_packet_size); 1784 if (rc) { 1785 ecryptfs_printk(KERN_ERR, "Error parsing " 1786 "tag 3 packet\n"); 1787 rc = -EIO; 1788 goto out_wipe_list; 1789 } 1790 i += packet_size; 1791 rc = parse_tag_11_packet((unsigned char *)&src[i], 1792 sig_tmp_space, 1793 ECRYPTFS_SIG_SIZE, 1794 &tag_11_contents_size, 1795 &tag_11_packet_size, 1796 max_packet_size); 1797 if (rc) { 1798 ecryptfs_printk(KERN_ERR, "No valid " 1799 "(ecryptfs-specific) literal " 1800 "packet containing " 1801 "authentication token " 1802 "signature found after " 1803 "tag 3 packet\n"); 1804 rc = -EIO; 1805 goto out_wipe_list; 1806 } 1807 i += tag_11_packet_size; 1808 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1809 ecryptfs_printk(KERN_ERR, "Expected " 1810 "signature of size [%d]; " 1811 "read size [%zd]\n", 1812 ECRYPTFS_SIG_SIZE, 1813 tag_11_contents_size); 1814 rc = -EIO; 1815 goto out_wipe_list; 1816 } 1817 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1818 sig_tmp_space, tag_11_contents_size); 1819 new_auth_tok->token.password.signature[ 1820 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1821 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1822 break; 1823 case ECRYPTFS_TAG_1_PACKET_TYPE: 1824 rc = parse_tag_1_packet(crypt_stat, 1825 (unsigned char *)&src[i], 1826 &auth_tok_list, &new_auth_tok, 1827 &packet_size, max_packet_size); 1828 if (rc) { 1829 ecryptfs_printk(KERN_ERR, "Error parsing " 1830 "tag 1 packet\n"); 1831 rc = -EIO; 1832 goto out_wipe_list; 1833 } 1834 i += packet_size; 1835 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1836 break; 1837 case ECRYPTFS_TAG_11_PACKET_TYPE: 1838 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1839 "(Tag 11 not allowed by itself)\n"); 1840 rc = -EIO; 1841 goto out_wipe_list; 1842 default: 1843 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1844 "of the file header; hex value of " 1845 "character is [0x%.2x]\n", i, src[i]); 1846 next_packet_is_auth_tok_packet = 0; 1847 } 1848 } 1849 if (list_empty(&auth_tok_list)) { 1850 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1851 "eCryptfs file; this is not supported in this version " 1852 "of the eCryptfs kernel module\n"); 1853 rc = -EINVAL; 1854 goto out; 1855 } 1856 /* auth_tok_list contains the set of authentication tokens 1857 * parsed from the metadata. We need to find a matching 1858 * authentication token that has the secret component(s) 1859 * necessary to decrypt the EFEK in the auth_tok parsed from 1860 * the metadata. There may be several potential matches, but 1861 * just one will be sufficient to decrypt to get the FEK. */ 1862 find_next_matching_auth_tok: 1863 found_auth_tok = 0; 1864 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1865 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1866 if (unlikely(ecryptfs_verbosity > 0)) { 1867 ecryptfs_printk(KERN_DEBUG, 1868 "Considering candidate auth tok:\n"); 1869 ecryptfs_dump_auth_tok(candidate_auth_tok); 1870 } 1871 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1872 candidate_auth_tok); 1873 if (rc) { 1874 printk(KERN_ERR 1875 "Unrecognized candidate auth tok type: [%d]\n", 1876 candidate_auth_tok->token_type); 1877 rc = -EINVAL; 1878 goto out_wipe_list; 1879 } 1880 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1881 &matching_auth_tok, 1882 crypt_stat->mount_crypt_stat, 1883 candidate_auth_tok_sig); 1884 if (!rc) { 1885 found_auth_tok = 1; 1886 goto found_matching_auth_tok; 1887 } 1888 } 1889 if (!found_auth_tok) { 1890 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1891 "authentication token\n"); 1892 rc = -EIO; 1893 goto out_wipe_list; 1894 } 1895 found_matching_auth_tok: 1896 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1897 memcpy(&(candidate_auth_tok->token.private_key), 1898 &(matching_auth_tok->token.private_key), 1899 sizeof(struct ecryptfs_private_key)); 1900 up_write(&(auth_tok_key->sem)); 1901 key_put(auth_tok_key); 1902 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1903 crypt_stat); 1904 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1905 memcpy(&(candidate_auth_tok->token.password), 1906 &(matching_auth_tok->token.password), 1907 sizeof(struct ecryptfs_password)); 1908 up_write(&(auth_tok_key->sem)); 1909 key_put(auth_tok_key); 1910 rc = decrypt_passphrase_encrypted_session_key( 1911 candidate_auth_tok, crypt_stat); 1912 } else { 1913 up_write(&(auth_tok_key->sem)); 1914 key_put(auth_tok_key); 1915 rc = -EINVAL; 1916 } 1917 if (rc) { 1918 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1919 1920 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1921 "session key for authentication token with sig " 1922 "[%.*s]; rc = [%d]. Removing auth tok " 1923 "candidate from the list and searching for " 1924 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1925 candidate_auth_tok_sig, rc); 1926 list_for_each_entry_safe(auth_tok_list_item, 1927 auth_tok_list_item_tmp, 1928 &auth_tok_list, list) { 1929 if (candidate_auth_tok 1930 == &auth_tok_list_item->auth_tok) { 1931 list_del(&auth_tok_list_item->list); 1932 kmem_cache_free( 1933 ecryptfs_auth_tok_list_item_cache, 1934 auth_tok_list_item); 1935 goto find_next_matching_auth_tok; 1936 } 1937 } 1938 BUG(); 1939 } 1940 rc = ecryptfs_compute_root_iv(crypt_stat); 1941 if (rc) { 1942 ecryptfs_printk(KERN_ERR, "Error computing " 1943 "the root IV\n"); 1944 goto out_wipe_list; 1945 } 1946 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1947 if (rc) { 1948 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1949 "context for cipher [%s]; rc = [%d]\n", 1950 crypt_stat->cipher, rc); 1951 } 1952 out_wipe_list: 1953 wipe_auth_tok_list(&auth_tok_list); 1954 out: 1955 return rc; 1956 } 1957 1958 static int 1959 pki_encrypt_session_key(struct key *auth_tok_key, 1960 struct ecryptfs_auth_tok *auth_tok, 1961 struct ecryptfs_crypt_stat *crypt_stat, 1962 struct ecryptfs_key_record *key_rec) 1963 { 1964 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1965 char *payload = NULL; 1966 size_t payload_len = 0; 1967 struct ecryptfs_message *msg; 1968 int rc; 1969 1970 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1971 ecryptfs_code_for_cipher_string( 1972 crypt_stat->cipher, 1973 crypt_stat->key_size), 1974 crypt_stat, &payload, &payload_len); 1975 up_write(&(auth_tok_key->sem)); 1976 key_put(auth_tok_key); 1977 if (rc) { 1978 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1979 goto out; 1980 } 1981 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1982 if (rc) { 1983 ecryptfs_printk(KERN_ERR, "Error sending message to " 1984 "ecryptfsd: %d\n", rc); 1985 goto out; 1986 } 1987 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1988 if (rc) { 1989 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 1990 "from the user space daemon\n"); 1991 rc = -EIO; 1992 goto out; 1993 } 1994 rc = parse_tag_67_packet(key_rec, msg); 1995 if (rc) 1996 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 1997 kfree(msg); 1998 out: 1999 kfree(payload); 2000 return rc; 2001 } 2002 /** 2003 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2004 * @dest: Buffer into which to write the packet 2005 * @remaining_bytes: Maximum number of bytes that can be writtn 2006 * @auth_tok_key: The authentication token key to unlock and put when done with 2007 * @auth_tok 2008 * @auth_tok: The authentication token used for generating the tag 1 packet 2009 * @crypt_stat: The cryptographic context 2010 * @key_rec: The key record struct for the tag 1 packet 2011 * @packet_size: This function will write the number of bytes that end 2012 * up constituting the packet; set to zero on error 2013 * 2014 * Returns zero on success; non-zero on error. 2015 */ 2016 static int 2017 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2018 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2019 struct ecryptfs_crypt_stat *crypt_stat, 2020 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2021 { 2022 size_t i; 2023 size_t encrypted_session_key_valid = 0; 2024 size_t packet_size_length; 2025 size_t max_packet_size; 2026 int rc = 0; 2027 2028 (*packet_size) = 0; 2029 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2030 ECRYPTFS_SIG_SIZE); 2031 encrypted_session_key_valid = 0; 2032 for (i = 0; i < crypt_stat->key_size; i++) 2033 encrypted_session_key_valid |= 2034 auth_tok->session_key.encrypted_key[i]; 2035 if (encrypted_session_key_valid) { 2036 memcpy(key_rec->enc_key, 2037 auth_tok->session_key.encrypted_key, 2038 auth_tok->session_key.encrypted_key_size); 2039 up_write(&(auth_tok_key->sem)); 2040 key_put(auth_tok_key); 2041 goto encrypted_session_key_set; 2042 } 2043 if (auth_tok->session_key.encrypted_key_size == 0) 2044 auth_tok->session_key.encrypted_key_size = 2045 auth_tok->token.private_key.key_size; 2046 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2047 key_rec); 2048 if (rc) { 2049 printk(KERN_ERR "Failed to encrypt session key via a key " 2050 "module; rc = [%d]\n", rc); 2051 goto out; 2052 } 2053 if (ecryptfs_verbosity > 0) { 2054 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2055 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2056 } 2057 encrypted_session_key_set: 2058 /* This format is inspired by OpenPGP; see RFC 2440 2059 * packet tag 1 */ 2060 max_packet_size = (1 /* Tag 1 identifier */ 2061 + 3 /* Max Tag 1 packet size */ 2062 + 1 /* Version */ 2063 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2064 + 1 /* Cipher identifier */ 2065 + key_rec->enc_key_size); /* Encrypted key size */ 2066 if (max_packet_size > (*remaining_bytes)) { 2067 printk(KERN_ERR "Packet length larger than maximum allowable; " 2068 "need up to [%td] bytes, but there are only [%td] " 2069 "available\n", max_packet_size, (*remaining_bytes)); 2070 rc = -EINVAL; 2071 goto out; 2072 } 2073 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2074 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2075 (max_packet_size - 4), 2076 &packet_size_length); 2077 if (rc) { 2078 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2079 "header; cannot generate packet length\n"); 2080 goto out; 2081 } 2082 (*packet_size) += packet_size_length; 2083 dest[(*packet_size)++] = 0x03; /* version 3 */ 2084 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2085 (*packet_size) += ECRYPTFS_SIG_SIZE; 2086 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2087 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2088 key_rec->enc_key_size); 2089 (*packet_size) += key_rec->enc_key_size; 2090 out: 2091 if (rc) 2092 (*packet_size) = 0; 2093 else 2094 (*remaining_bytes) -= (*packet_size); 2095 return rc; 2096 } 2097 2098 /** 2099 * write_tag_11_packet 2100 * @dest: Target into which Tag 11 packet is to be written 2101 * @remaining_bytes: Maximum packet length 2102 * @contents: Byte array of contents to copy in 2103 * @contents_length: Number of bytes in contents 2104 * @packet_length: Length of the Tag 11 packet written; zero on error 2105 * 2106 * Returns zero on success; non-zero on error. 2107 */ 2108 static int 2109 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2110 size_t contents_length, size_t *packet_length) 2111 { 2112 size_t packet_size_length; 2113 size_t max_packet_size; 2114 int rc = 0; 2115 2116 (*packet_length) = 0; 2117 /* This format is inspired by OpenPGP; see RFC 2440 2118 * packet tag 11 */ 2119 max_packet_size = (1 /* Tag 11 identifier */ 2120 + 3 /* Max Tag 11 packet size */ 2121 + 1 /* Binary format specifier */ 2122 + 1 /* Filename length */ 2123 + 8 /* Filename ("_CONSOLE") */ 2124 + 4 /* Modification date */ 2125 + contents_length); /* Literal data */ 2126 if (max_packet_size > (*remaining_bytes)) { 2127 printk(KERN_ERR "Packet length larger than maximum allowable; " 2128 "need up to [%td] bytes, but there are only [%td] " 2129 "available\n", max_packet_size, (*remaining_bytes)); 2130 rc = -EINVAL; 2131 goto out; 2132 } 2133 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2134 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2135 (max_packet_size - 4), 2136 &packet_size_length); 2137 if (rc) { 2138 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2139 "generate packet length. rc = [%d]\n", rc); 2140 goto out; 2141 } 2142 (*packet_length) += packet_size_length; 2143 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2144 dest[(*packet_length)++] = 8; 2145 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2146 (*packet_length) += 8; 2147 memset(&dest[(*packet_length)], 0x00, 4); 2148 (*packet_length) += 4; 2149 memcpy(&dest[(*packet_length)], contents, contents_length); 2150 (*packet_length) += contents_length; 2151 out: 2152 if (rc) 2153 (*packet_length) = 0; 2154 else 2155 (*remaining_bytes) -= (*packet_length); 2156 return rc; 2157 } 2158 2159 /** 2160 * write_tag_3_packet 2161 * @dest: Buffer into which to write the packet 2162 * @remaining_bytes: Maximum number of bytes that can be written 2163 * @auth_tok: Authentication token 2164 * @crypt_stat: The cryptographic context 2165 * @key_rec: encrypted key 2166 * @packet_size: This function will write the number of bytes that end 2167 * up constituting the packet; set to zero on error 2168 * 2169 * Returns zero on success; non-zero on error. 2170 */ 2171 static int 2172 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2173 struct ecryptfs_auth_tok *auth_tok, 2174 struct ecryptfs_crypt_stat *crypt_stat, 2175 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2176 { 2177 size_t i; 2178 size_t encrypted_session_key_valid = 0; 2179 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2180 struct scatterlist dst_sg[2]; 2181 struct scatterlist src_sg[2]; 2182 struct mutex *tfm_mutex = NULL; 2183 u8 cipher_code; 2184 size_t packet_size_length; 2185 size_t max_packet_size; 2186 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2187 crypt_stat->mount_crypt_stat; 2188 struct crypto_skcipher *tfm; 2189 struct skcipher_request *req; 2190 int rc = 0; 2191 2192 (*packet_size) = 0; 2193 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2194 ECRYPTFS_SIG_SIZE); 2195 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 2196 crypt_stat->cipher); 2197 if (unlikely(rc)) { 2198 printk(KERN_ERR "Internal error whilst attempting to get " 2199 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2200 crypt_stat->cipher, rc); 2201 goto out; 2202 } 2203 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2204 printk(KERN_WARNING "No key size specified at mount; " 2205 "defaulting to [%d]\n", 2206 crypto_skcipher_default_keysize(tfm)); 2207 mount_crypt_stat->global_default_cipher_key_size = 2208 crypto_skcipher_default_keysize(tfm); 2209 } 2210 if (crypt_stat->key_size == 0) 2211 crypt_stat->key_size = 2212 mount_crypt_stat->global_default_cipher_key_size; 2213 if (auth_tok->session_key.encrypted_key_size == 0) 2214 auth_tok->session_key.encrypted_key_size = 2215 crypt_stat->key_size; 2216 if (crypt_stat->key_size == 24 2217 && strcmp("aes", crypt_stat->cipher) == 0) { 2218 memset((crypt_stat->key + 24), 0, 8); 2219 auth_tok->session_key.encrypted_key_size = 32; 2220 } else 2221 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2222 key_rec->enc_key_size = 2223 auth_tok->session_key.encrypted_key_size; 2224 encrypted_session_key_valid = 0; 2225 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2226 encrypted_session_key_valid |= 2227 auth_tok->session_key.encrypted_key[i]; 2228 if (encrypted_session_key_valid) { 2229 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2230 "using auth_tok->session_key.encrypted_key, " 2231 "where key_rec->enc_key_size = [%zd]\n", 2232 key_rec->enc_key_size); 2233 memcpy(key_rec->enc_key, 2234 auth_tok->session_key.encrypted_key, 2235 key_rec->enc_key_size); 2236 goto encrypted_session_key_set; 2237 } 2238 if (auth_tok->token.password.flags & 2239 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2240 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2241 "session key encryption key of size [%d]\n", 2242 auth_tok->token.password. 2243 session_key_encryption_key_bytes); 2244 memcpy(session_key_encryption_key, 2245 auth_tok->token.password.session_key_encryption_key, 2246 crypt_stat->key_size); 2247 ecryptfs_printk(KERN_DEBUG, 2248 "Cached session key encryption key:\n"); 2249 if (ecryptfs_verbosity > 0) 2250 ecryptfs_dump_hex(session_key_encryption_key, 16); 2251 } 2252 if (unlikely(ecryptfs_verbosity > 0)) { 2253 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2254 ecryptfs_dump_hex(session_key_encryption_key, 16); 2255 } 2256 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2257 src_sg, 2); 2258 if (rc < 1 || rc > 2) { 2259 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2260 "for crypt_stat session key; expected rc = 1; " 2261 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2262 rc, key_rec->enc_key_size); 2263 rc = -ENOMEM; 2264 goto out; 2265 } 2266 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2267 dst_sg, 2); 2268 if (rc < 1 || rc > 2) { 2269 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2270 "for crypt_stat encrypted session key; " 2271 "expected rc = 1; got rc = [%d]. " 2272 "key_rec->enc_key_size = [%zd]\n", rc, 2273 key_rec->enc_key_size); 2274 rc = -ENOMEM; 2275 goto out; 2276 } 2277 mutex_lock(tfm_mutex); 2278 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key, 2279 crypt_stat->key_size); 2280 if (rc < 0) { 2281 mutex_unlock(tfm_mutex); 2282 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2283 "context; rc = [%d]\n", rc); 2284 goto out; 2285 } 2286 2287 req = skcipher_request_alloc(tfm, GFP_KERNEL); 2288 if (!req) { 2289 mutex_unlock(tfm_mutex); 2290 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " 2291 "attempting to skcipher_request_alloc for " 2292 "%s\n", crypto_skcipher_driver_name(tfm)); 2293 rc = -ENOMEM; 2294 goto out; 2295 } 2296 2297 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 2298 NULL, NULL); 2299 2300 rc = 0; 2301 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2302 crypt_stat->key_size); 2303 skcipher_request_set_crypt(req, src_sg, dst_sg, 2304 (*key_rec).enc_key_size, NULL); 2305 rc = crypto_skcipher_encrypt(req); 2306 mutex_unlock(tfm_mutex); 2307 skcipher_request_free(req); 2308 if (rc) { 2309 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2310 goto out; 2311 } 2312 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2313 if (ecryptfs_verbosity > 0) { 2314 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2315 key_rec->enc_key_size); 2316 ecryptfs_dump_hex(key_rec->enc_key, 2317 key_rec->enc_key_size); 2318 } 2319 encrypted_session_key_set: 2320 /* This format is inspired by OpenPGP; see RFC 2440 2321 * packet tag 3 */ 2322 max_packet_size = (1 /* Tag 3 identifier */ 2323 + 3 /* Max Tag 3 packet size */ 2324 + 1 /* Version */ 2325 + 1 /* Cipher code */ 2326 + 1 /* S2K specifier */ 2327 + 1 /* Hash identifier */ 2328 + ECRYPTFS_SALT_SIZE /* Salt */ 2329 + 1 /* Hash iterations */ 2330 + key_rec->enc_key_size); /* Encrypted key size */ 2331 if (max_packet_size > (*remaining_bytes)) { 2332 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2333 "there are only [%td] available\n", max_packet_size, 2334 (*remaining_bytes)); 2335 rc = -EINVAL; 2336 goto out; 2337 } 2338 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2339 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2340 * to get the number of octets in the actual Tag 3 packet */ 2341 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2342 (max_packet_size - 4), 2343 &packet_size_length); 2344 if (rc) { 2345 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2346 "generate packet length. rc = [%d]\n", rc); 2347 goto out; 2348 } 2349 (*packet_size) += packet_size_length; 2350 dest[(*packet_size)++] = 0x04; /* version 4 */ 2351 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2352 * specified with strings */ 2353 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2354 crypt_stat->key_size); 2355 if (cipher_code == 0) { 2356 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2357 "cipher [%s]\n", crypt_stat->cipher); 2358 rc = -EINVAL; 2359 goto out; 2360 } 2361 dest[(*packet_size)++] = cipher_code; 2362 dest[(*packet_size)++] = 0x03; /* S2K */ 2363 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2364 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2365 ECRYPTFS_SALT_SIZE); 2366 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2367 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2368 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2369 key_rec->enc_key_size); 2370 (*packet_size) += key_rec->enc_key_size; 2371 out: 2372 if (rc) 2373 (*packet_size) = 0; 2374 else 2375 (*remaining_bytes) -= (*packet_size); 2376 return rc; 2377 } 2378 2379 struct kmem_cache *ecryptfs_key_record_cache; 2380 2381 /** 2382 * ecryptfs_generate_key_packet_set 2383 * @dest_base: Virtual address from which to write the key record set 2384 * @crypt_stat: The cryptographic context from which the 2385 * authentication tokens will be retrieved 2386 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2387 * for the global parameters 2388 * @len: The amount written 2389 * @max: The maximum amount of data allowed to be written 2390 * 2391 * Generates a key packet set and writes it to the virtual address 2392 * passed in. 2393 * 2394 * Returns zero on success; non-zero on error. 2395 */ 2396 int 2397 ecryptfs_generate_key_packet_set(char *dest_base, 2398 struct ecryptfs_crypt_stat *crypt_stat, 2399 struct dentry *ecryptfs_dentry, size_t *len, 2400 size_t max) 2401 { 2402 struct ecryptfs_auth_tok *auth_tok; 2403 struct key *auth_tok_key = NULL; 2404 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2405 &ecryptfs_superblock_to_private( 2406 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2407 size_t written; 2408 struct ecryptfs_key_record *key_rec; 2409 struct ecryptfs_key_sig *key_sig; 2410 int rc = 0; 2411 2412 (*len) = 0; 2413 mutex_lock(&crypt_stat->keysig_list_mutex); 2414 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2415 if (!key_rec) { 2416 rc = -ENOMEM; 2417 goto out; 2418 } 2419 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2420 crypt_stat_list) { 2421 memset(key_rec, 0, sizeof(*key_rec)); 2422 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2423 &auth_tok, 2424 mount_crypt_stat, 2425 key_sig->keysig); 2426 if (rc) { 2427 printk(KERN_WARNING "Unable to retrieve auth tok with " 2428 "sig = [%s]\n", key_sig->keysig); 2429 rc = process_find_global_auth_tok_for_sig_err(rc); 2430 goto out_free; 2431 } 2432 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2433 rc = write_tag_3_packet((dest_base + (*len)), 2434 &max, auth_tok, 2435 crypt_stat, key_rec, 2436 &written); 2437 up_write(&(auth_tok_key->sem)); 2438 key_put(auth_tok_key); 2439 if (rc) { 2440 ecryptfs_printk(KERN_WARNING, "Error " 2441 "writing tag 3 packet\n"); 2442 goto out_free; 2443 } 2444 (*len) += written; 2445 /* Write auth tok signature packet */ 2446 rc = write_tag_11_packet((dest_base + (*len)), &max, 2447 key_rec->sig, 2448 ECRYPTFS_SIG_SIZE, &written); 2449 if (rc) { 2450 ecryptfs_printk(KERN_ERR, "Error writing " 2451 "auth tok signature packet\n"); 2452 goto out_free; 2453 } 2454 (*len) += written; 2455 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2456 rc = write_tag_1_packet(dest_base + (*len), &max, 2457 auth_tok_key, auth_tok, 2458 crypt_stat, key_rec, &written); 2459 if (rc) { 2460 ecryptfs_printk(KERN_WARNING, "Error " 2461 "writing tag 1 packet\n"); 2462 goto out_free; 2463 } 2464 (*len) += written; 2465 } else { 2466 up_write(&(auth_tok_key->sem)); 2467 key_put(auth_tok_key); 2468 ecryptfs_printk(KERN_WARNING, "Unsupported " 2469 "authentication token type\n"); 2470 rc = -EINVAL; 2471 goto out_free; 2472 } 2473 } 2474 if (likely(max > 0)) { 2475 dest_base[(*len)] = 0x00; 2476 } else { 2477 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2478 rc = -EIO; 2479 } 2480 out_free: 2481 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2482 out: 2483 if (rc) 2484 (*len) = 0; 2485 mutex_unlock(&crypt_stat->keysig_list_mutex); 2486 return rc; 2487 } 2488 2489 struct kmem_cache *ecryptfs_key_sig_cache; 2490 2491 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2492 { 2493 struct ecryptfs_key_sig *new_key_sig; 2494 2495 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2496 if (!new_key_sig) 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 2515 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2516 GFP_KERNEL); 2517 if (!new_auth_tok) 2518 return -ENOMEM; 2519 2520 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2521 new_auth_tok->flags = global_auth_tok_flags; 2522 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2523 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2524 list_add(&new_auth_tok->mount_crypt_stat_list, 2525 &mount_crypt_stat->global_auth_tok_list); 2526 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2527 return 0; 2528 } 2529 2530