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 * | Cipher Code | 1 byte | 304 * | File Encryption Key | arbitrary | 305 * | Checksum | 2 bytes | 306 */ 307 data_len = (8 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); 308 *packet = kmalloc(data_len, GFP_KERNEL); 309 message = *packet; 310 if (!message) { 311 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 312 rc = -ENOMEM; 313 goto out; 314 } 315 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; 316 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 317 &packet_size_len); 318 if (rc) { 319 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 320 "header; cannot generate packet length\n"); 321 goto out; 322 } 323 i += packet_size_len; 324 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 325 i += ECRYPTFS_SIG_SIZE_HEX; 326 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */ 327 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, 328 &packet_size_len); 329 if (rc) { 330 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 331 "header; cannot generate packet length\n"); 332 goto out; 333 } 334 i += packet_size_len; 335 message[i++] = cipher_code; 336 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); 337 i += crypt_stat->key_size; 338 for (j = 0; j < crypt_stat->key_size; j++) 339 checksum += crypt_stat->key[j]; 340 message[i++] = (checksum / 256) % 256; 341 message[i++] = (checksum % 256); 342 *packet_len = i; 343 out: 344 return rc; 345 } 346 347 static int 348 parse_tag_67_packet(struct ecryptfs_key_record *key_rec, 349 struct ecryptfs_message *msg) 350 { 351 size_t i = 0; 352 char *data; 353 size_t data_len; 354 size_t message_len; 355 int rc; 356 357 /* 358 * ***** TAG 65 Packet Format ***** 359 * | Content Type | 1 byte | 360 * | Status Indicator | 1 byte | 361 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 362 * | Encrypted File Encryption Key | arbitrary | 363 */ 364 message_len = msg->data_len; 365 data = msg->data; 366 /* verify that everything through the encrypted FEK size is present */ 367 if (message_len < 4) { 368 rc = -EIO; 369 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " 370 "message length is [%d]\n", __func__, message_len, 4); 371 goto out; 372 } 373 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { 374 rc = -EIO; 375 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", 376 __func__); 377 goto out; 378 } 379 if (data[i++]) { 380 rc = -EIO; 381 printk(KERN_ERR "%s: Status indicator has non zero " 382 "value [%d]\n", __func__, data[i-1]); 383 384 goto out; 385 } 386 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, 387 &data_len); 388 if (rc) { 389 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 390 "rc = [%d]\n", rc); 391 goto out; 392 } 393 i += data_len; 394 if (message_len < (i + key_rec->enc_key_size)) { 395 rc = -EIO; 396 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", 397 __func__, message_len, (i + key_rec->enc_key_size)); 398 goto out; 399 } 400 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 401 rc = -EIO; 402 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " 403 "the maximum key size [%d]\n", __func__, 404 key_rec->enc_key_size, 405 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 406 goto out; 407 } 408 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); 409 out: 410 return rc; 411 } 412 413 /** 414 * ecryptfs_verify_version 415 * @version: The version number to confirm 416 * 417 * Returns zero on good version; non-zero otherwise 418 */ 419 static int ecryptfs_verify_version(u16 version) 420 { 421 int rc = 0; 422 unsigned char major; 423 unsigned char minor; 424 425 major = ((version >> 8) & 0xFF); 426 minor = (version & 0xFF); 427 if (major != ECRYPTFS_VERSION_MAJOR) { 428 ecryptfs_printk(KERN_ERR, "Major version number mismatch. " 429 "Expected [%d]; got [%d]\n", 430 ECRYPTFS_VERSION_MAJOR, major); 431 rc = -EINVAL; 432 goto out; 433 } 434 if (minor != ECRYPTFS_VERSION_MINOR) { 435 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " 436 "Expected [%d]; got [%d]\n", 437 ECRYPTFS_VERSION_MINOR, minor); 438 rc = -EINVAL; 439 goto out; 440 } 441 out: 442 return rc; 443 } 444 445 /** 446 * ecryptfs_verify_auth_tok_from_key 447 * @auth_tok_key: key containing the authentication token 448 * @auth_tok: authentication token 449 * 450 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or 451 * -EKEYREVOKED if the key was revoked before we acquired its semaphore. 452 */ 453 static int 454 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, 455 struct ecryptfs_auth_tok **auth_tok) 456 { 457 int rc = 0; 458 459 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); 460 if (IS_ERR(*auth_tok)) { 461 rc = PTR_ERR(*auth_tok); 462 *auth_tok = NULL; 463 goto out; 464 } 465 466 if (ecryptfs_verify_version((*auth_tok)->version)) { 467 printk(KERN_ERR "Data structure version mismatch. Userspace " 468 "tools must match eCryptfs kernel module with major " 469 "version [%d] and minor version [%d]\n", 470 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); 471 rc = -EINVAL; 472 goto out; 473 } 474 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD 475 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { 476 printk(KERN_ERR "Invalid auth_tok structure " 477 "returned from key query\n"); 478 rc = -EINVAL; 479 goto out; 480 } 481 out: 482 return rc; 483 } 484 485 static int 486 ecryptfs_find_global_auth_tok_for_sig( 487 struct key **auth_tok_key, 488 struct ecryptfs_auth_tok **auth_tok, 489 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) 490 { 491 struct ecryptfs_global_auth_tok *walker; 492 int rc = 0; 493 494 (*auth_tok_key) = NULL; 495 (*auth_tok) = NULL; 496 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 497 list_for_each_entry(walker, 498 &mount_crypt_stat->global_auth_tok_list, 499 mount_crypt_stat_list) { 500 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) 501 continue; 502 503 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { 504 rc = -EINVAL; 505 goto out; 506 } 507 508 rc = key_validate(walker->global_auth_tok_key); 509 if (rc) { 510 if (rc == -EKEYEXPIRED) 511 goto out; 512 goto out_invalid_auth_tok; 513 } 514 515 down_write(&(walker->global_auth_tok_key->sem)); 516 rc = ecryptfs_verify_auth_tok_from_key( 517 walker->global_auth_tok_key, auth_tok); 518 if (rc) 519 goto out_invalid_auth_tok_unlock; 520 521 (*auth_tok_key) = walker->global_auth_tok_key; 522 key_get(*auth_tok_key); 523 goto out; 524 } 525 rc = -ENOENT; 526 goto out; 527 out_invalid_auth_tok_unlock: 528 up_write(&(walker->global_auth_tok_key->sem)); 529 out_invalid_auth_tok: 530 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); 531 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; 532 key_put(walker->global_auth_tok_key); 533 walker->global_auth_tok_key = NULL; 534 out: 535 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 536 return rc; 537 } 538 539 /** 540 * ecryptfs_find_auth_tok_for_sig 541 * @auth_tok_key: key containing the authentication token 542 * @auth_tok: Set to the matching auth_tok; NULL if not found 543 * @mount_crypt_stat: inode crypt_stat crypto context 544 * @sig: Sig of auth_tok to find 545 * 546 * For now, this function simply looks at the registered auth_tok's 547 * linked off the mount_crypt_stat, so all the auth_toks that can be 548 * used must be registered at mount time. This function could 549 * potentially try a lot harder to find auth_tok's (e.g., by calling 550 * out to ecryptfsd to dynamically retrieve an auth_tok object) so 551 * that static registration of auth_tok's will no longer be necessary. 552 * 553 * Returns zero on no error; non-zero on error 554 */ 555 static int 556 ecryptfs_find_auth_tok_for_sig( 557 struct key **auth_tok_key, 558 struct ecryptfs_auth_tok **auth_tok, 559 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 560 char *sig) 561 { 562 int rc = 0; 563 564 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, 565 mount_crypt_stat, sig); 566 if (rc == -ENOENT) { 567 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the 568 * mount_crypt_stat structure, we prevent to use auth toks that 569 * are not inserted through the ecryptfs_add_global_auth_tok 570 * function. 571 */ 572 if (mount_crypt_stat->flags 573 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) 574 return -EINVAL; 575 576 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, 577 sig); 578 } 579 return rc; 580 } 581 582 /* 583 * write_tag_70_packet can gobble a lot of stack space. We stuff most 584 * of the function's parameters in a kmalloc'd struct to help reduce 585 * eCryptfs' overall stack usage. 586 */ 587 struct ecryptfs_write_tag_70_packet_silly_stack { 588 u8 cipher_code; 589 size_t max_packet_size; 590 size_t packet_size_len; 591 size_t block_aligned_filename_size; 592 size_t block_size; 593 size_t i; 594 size_t j; 595 size_t num_rand_bytes; 596 struct mutex *tfm_mutex; 597 char *block_aligned_filename; 598 struct ecryptfs_auth_tok *auth_tok; 599 struct scatterlist src_sg[2]; 600 struct scatterlist dst_sg[2]; 601 struct crypto_skcipher *skcipher_tfm; 602 struct skcipher_request *skcipher_req; 603 char iv[ECRYPTFS_MAX_IV_BYTES]; 604 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 605 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 606 struct crypto_shash *hash_tfm; 607 struct shash_desc *hash_desc; 608 }; 609 610 /* 611 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK 612 * @filename: NULL-terminated filename string 613 * 614 * This is the simplest mechanism for achieving filename encryption in 615 * eCryptfs. It encrypts the given filename with the mount-wide 616 * filename encryption key (FNEK) and stores it in a packet to @dest, 617 * which the callee will encode and write directly into the dentry 618 * name. 619 */ 620 int 621 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, 622 size_t *packet_size, 623 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 624 char *filename, size_t filename_size) 625 { 626 struct ecryptfs_write_tag_70_packet_silly_stack *s; 627 struct key *auth_tok_key = NULL; 628 int rc = 0; 629 630 s = kzalloc(sizeof(*s), GFP_KERNEL); 631 if (!s) 632 return -ENOMEM; 633 634 (*packet_size) = 0; 635 rc = ecryptfs_find_auth_tok_for_sig( 636 &auth_tok_key, 637 &s->auth_tok, mount_crypt_stat, 638 mount_crypt_stat->global_default_fnek_sig); 639 if (rc) { 640 printk(KERN_ERR "%s: Error attempting to find auth tok for " 641 "fnek sig [%s]; rc = [%d]\n", __func__, 642 mount_crypt_stat->global_default_fnek_sig, rc); 643 goto out; 644 } 645 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 646 &s->skcipher_tfm, 647 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 648 if (unlikely(rc)) { 649 printk(KERN_ERR "Internal error whilst attempting to get " 650 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 651 mount_crypt_stat->global_default_fn_cipher_name, rc); 652 goto out; 653 } 654 mutex_lock(s->tfm_mutex); 655 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm); 656 /* Plus one for the \0 separator between the random prefix 657 * and the plaintext filename */ 658 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 659 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 660 if ((s->block_aligned_filename_size % s->block_size) != 0) { 661 s->num_rand_bytes += (s->block_size 662 - (s->block_aligned_filename_size 663 % s->block_size)); 664 s->block_aligned_filename_size = (s->num_rand_bytes 665 + filename_size); 666 } 667 /* Octet 0: Tag 70 identifier 668 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 669 * and block-aligned encrypted filename size) 670 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 671 * Octet N2-N3: Cipher identifier (1 octet) 672 * Octets N3-N4: Block-aligned encrypted filename 673 * - Consists of a minimum number of random characters, a \0 674 * separator, and then the filename */ 675 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 676 + s->block_aligned_filename_size); 677 if (!dest) { 678 (*packet_size) = s->max_packet_size; 679 goto out_unlock; 680 } 681 if (s->max_packet_size > (*remaining_bytes)) { 682 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 683 "[%zd] available\n", __func__, s->max_packet_size, 684 (*remaining_bytes)); 685 rc = -EINVAL; 686 goto out_unlock; 687 } 688 689 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 690 if (!s->skcipher_req) { 691 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 692 "skcipher_request_alloc for %s\n", __func__, 693 crypto_skcipher_driver_name(s->skcipher_tfm)); 694 rc = -ENOMEM; 695 goto out_unlock; 696 } 697 698 skcipher_request_set_callback(s->skcipher_req, 699 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 700 701 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 702 GFP_KERNEL); 703 if (!s->block_aligned_filename) { 704 rc = -ENOMEM; 705 goto out_unlock; 706 } 707 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 708 rc = ecryptfs_write_packet_length(&dest[s->i], 709 (ECRYPTFS_SIG_SIZE 710 + 1 /* Cipher code */ 711 + s->block_aligned_filename_size), 712 &s->packet_size_len); 713 if (rc) { 714 printk(KERN_ERR "%s: Error generating tag 70 packet " 715 "header; cannot generate packet length; rc = [%d]\n", 716 __func__, rc); 717 goto out_free_unlock; 718 } 719 s->i += s->packet_size_len; 720 ecryptfs_from_hex(&dest[s->i], 721 mount_crypt_stat->global_default_fnek_sig, 722 ECRYPTFS_SIG_SIZE); 723 s->i += ECRYPTFS_SIG_SIZE; 724 s->cipher_code = ecryptfs_code_for_cipher_string( 725 mount_crypt_stat->global_default_fn_cipher_name, 726 mount_crypt_stat->global_default_fn_cipher_key_bytes); 727 if (s->cipher_code == 0) { 728 printk(KERN_WARNING "%s: Unable to generate code for " 729 "cipher [%s] with key bytes [%zd]\n", __func__, 730 mount_crypt_stat->global_default_fn_cipher_name, 731 mount_crypt_stat->global_default_fn_cipher_key_bytes); 732 rc = -EINVAL; 733 goto out_free_unlock; 734 } 735 dest[s->i++] = s->cipher_code; 736 /* TODO: Support other key modules than passphrase for 737 * filename encryption */ 738 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 739 rc = -EOPNOTSUPP; 740 printk(KERN_INFO "%s: Filename encryption only supports " 741 "password tokens\n", __func__); 742 goto out_free_unlock; 743 } 744 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0); 745 if (IS_ERR(s->hash_tfm)) { 746 rc = PTR_ERR(s->hash_tfm); 747 printk(KERN_ERR "%s: Error attempting to " 748 "allocate hash crypto context; rc = [%d]\n", 749 __func__, rc); 750 goto out_free_unlock; 751 } 752 753 s->hash_desc = kmalloc(sizeof(*s->hash_desc) + 754 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL); 755 if (!s->hash_desc) { 756 rc = -ENOMEM; 757 goto out_release_free_unlock; 758 } 759 760 s->hash_desc->tfm = s->hash_tfm; 761 762 rc = crypto_shash_digest(s->hash_desc, 763 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 764 s->auth_tok->token.password.session_key_encryption_key_bytes, 765 s->hash); 766 if (rc) { 767 printk(KERN_ERR 768 "%s: Error computing crypto hash; rc = [%d]\n", 769 __func__, rc); 770 goto out_release_free_unlock; 771 } 772 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 773 s->block_aligned_filename[s->j] = 774 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 775 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 776 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 777 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash, 778 ECRYPTFS_TAG_70_DIGEST_SIZE, 779 s->tmp_hash); 780 if (rc) { 781 printk(KERN_ERR 782 "%s: Error computing crypto hash; " 783 "rc = [%d]\n", __func__, rc); 784 goto out_release_free_unlock; 785 } 786 memcpy(s->hash, s->tmp_hash, 787 ECRYPTFS_TAG_70_DIGEST_SIZE); 788 } 789 if (s->block_aligned_filename[s->j] == '\0') 790 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 791 } 792 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 793 filename_size); 794 rc = virt_to_scatterlist(s->block_aligned_filename, 795 s->block_aligned_filename_size, s->src_sg, 2); 796 if (rc < 1) { 797 printk(KERN_ERR "%s: Internal error whilst attempting to " 798 "convert filename memory to scatterlist; rc = [%d]. " 799 "block_aligned_filename_size = [%zd]\n", __func__, rc, 800 s->block_aligned_filename_size); 801 goto out_release_free_unlock; 802 } 803 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 804 s->dst_sg, 2); 805 if (rc < 1) { 806 printk(KERN_ERR "%s: Internal error whilst attempting to " 807 "convert encrypted filename memory to scatterlist; " 808 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 809 __func__, rc, s->block_aligned_filename_size); 810 goto out_release_free_unlock; 811 } 812 /* The characters in the first block effectively do the job 813 * of the IV here, so we just use 0's for the IV. Note the 814 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 815 * >= ECRYPTFS_MAX_IV_BYTES. */ 816 rc = crypto_skcipher_setkey( 817 s->skcipher_tfm, 818 s->auth_tok->token.password.session_key_encryption_key, 819 mount_crypt_stat->global_default_fn_cipher_key_bytes); 820 if (rc < 0) { 821 printk(KERN_ERR "%s: Error setting key for crypto context; " 822 "rc = [%d]. s->auth_tok->token.password.session_key_" 823 "encryption_key = [0x%p]; mount_crypt_stat->" 824 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 825 rc, 826 s->auth_tok->token.password.session_key_encryption_key, 827 mount_crypt_stat->global_default_fn_cipher_key_bytes); 828 goto out_release_free_unlock; 829 } 830 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 831 s->block_aligned_filename_size, s->iv); 832 rc = crypto_skcipher_encrypt(s->skcipher_req); 833 if (rc) { 834 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 835 "rc = [%d]\n", __func__, rc); 836 goto out_release_free_unlock; 837 } 838 s->i += s->block_aligned_filename_size; 839 (*packet_size) = s->i; 840 (*remaining_bytes) -= (*packet_size); 841 out_release_free_unlock: 842 crypto_free_shash(s->hash_tfm); 843 out_free_unlock: 844 kfree_sensitive(s->block_aligned_filename); 845 out_unlock: 846 mutex_unlock(s->tfm_mutex); 847 out: 848 if (auth_tok_key) { 849 up_write(&(auth_tok_key->sem)); 850 key_put(auth_tok_key); 851 } 852 skcipher_request_free(s->skcipher_req); 853 kfree_sensitive(s->hash_desc); 854 kfree(s); 855 return rc; 856 } 857 858 struct ecryptfs_parse_tag_70_packet_silly_stack { 859 u8 cipher_code; 860 size_t max_packet_size; 861 size_t packet_size_len; 862 size_t parsed_tag_70_packet_size; 863 size_t block_aligned_filename_size; 864 size_t block_size; 865 size_t i; 866 struct mutex *tfm_mutex; 867 char *decrypted_filename; 868 struct ecryptfs_auth_tok *auth_tok; 869 struct scatterlist src_sg[2]; 870 struct scatterlist dst_sg[2]; 871 struct crypto_skcipher *skcipher_tfm; 872 struct skcipher_request *skcipher_req; 873 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 874 char iv[ECRYPTFS_MAX_IV_BYTES]; 875 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; 876 }; 877 878 /** 879 * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 880 * @filename: This function kmalloc's the memory for the filename 881 * @filename_size: This function sets this to the amount of memory 882 * kmalloc'd for the filename 883 * @packet_size: This function sets this to the the number of octets 884 * in the packet parsed 885 * @mount_crypt_stat: The mount-wide cryptographic context 886 * @data: The memory location containing the start of the tag 70 887 * packet 888 * @max_packet_size: The maximum legal size of the packet to be parsed 889 * from @data 890 * 891 * Returns zero on success; non-zero otherwise 892 */ 893 int 894 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 895 size_t *packet_size, 896 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 897 char *data, size_t max_packet_size) 898 { 899 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 900 struct key *auth_tok_key = NULL; 901 int rc = 0; 902 903 (*packet_size) = 0; 904 (*filename_size) = 0; 905 (*filename) = NULL; 906 s = kzalloc(sizeof(*s), GFP_KERNEL); 907 if (!s) 908 return -ENOMEM; 909 910 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 911 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 912 "at least [%d]\n", __func__, max_packet_size, 913 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 914 rc = -EINVAL; 915 goto out; 916 } 917 /* Octet 0: Tag 70 identifier 918 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 919 * and block-aligned encrypted filename size) 920 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 921 * Octet N2-N3: Cipher identifier (1 octet) 922 * Octets N3-N4: Block-aligned encrypted filename 923 * - Consists of a minimum number of random numbers, a \0 924 * separator, and then the filename */ 925 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 926 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 927 "tag [0x%.2x]\n", __func__, 928 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 929 rc = -EINVAL; 930 goto out; 931 } 932 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 933 &s->parsed_tag_70_packet_size, 934 &s->packet_size_len); 935 if (rc) { 936 printk(KERN_WARNING "%s: Error parsing packet length; " 937 "rc = [%d]\n", __func__, rc); 938 goto out; 939 } 940 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 941 - ECRYPTFS_SIG_SIZE - 1); 942 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 943 > max_packet_size) { 944 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 945 "size is [%zd]\n", __func__, max_packet_size, 946 (1 + s->packet_size_len + 1 947 + s->block_aligned_filename_size)); 948 rc = -EINVAL; 949 goto out; 950 } 951 (*packet_size) += s->packet_size_len; 952 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 953 ECRYPTFS_SIG_SIZE); 954 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 955 (*packet_size) += ECRYPTFS_SIG_SIZE; 956 s->cipher_code = data[(*packet_size)++]; 957 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 958 if (rc) { 959 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 960 __func__, s->cipher_code); 961 goto out; 962 } 963 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 964 &s->auth_tok, mount_crypt_stat, 965 s->fnek_sig_hex); 966 if (rc) { 967 printk(KERN_ERR "%s: Error attempting to find auth tok for " 968 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 969 rc); 970 goto out; 971 } 972 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm, 973 &s->tfm_mutex, 974 s->cipher_string); 975 if (unlikely(rc)) { 976 printk(KERN_ERR "Internal error whilst attempting to get " 977 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 978 s->cipher_string, rc); 979 goto out; 980 } 981 mutex_lock(s->tfm_mutex); 982 rc = virt_to_scatterlist(&data[(*packet_size)], 983 s->block_aligned_filename_size, s->src_sg, 2); 984 if (rc < 1) { 985 printk(KERN_ERR "%s: Internal error whilst attempting to " 986 "convert encrypted filename memory to scatterlist; " 987 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 988 __func__, rc, s->block_aligned_filename_size); 989 goto out_unlock; 990 } 991 (*packet_size) += s->block_aligned_filename_size; 992 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 993 GFP_KERNEL); 994 if (!s->decrypted_filename) { 995 rc = -ENOMEM; 996 goto out_unlock; 997 } 998 rc = virt_to_scatterlist(s->decrypted_filename, 999 s->block_aligned_filename_size, s->dst_sg, 2); 1000 if (rc < 1) { 1001 printk(KERN_ERR "%s: Internal error whilst attempting to " 1002 "convert decrypted filename memory to scatterlist; " 1003 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1004 __func__, rc, s->block_aligned_filename_size); 1005 goto out_free_unlock; 1006 } 1007 1008 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 1009 if (!s->skcipher_req) { 1010 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1011 "skcipher_request_alloc for %s\n", __func__, 1012 crypto_skcipher_driver_name(s->skcipher_tfm)); 1013 rc = -ENOMEM; 1014 goto out_free_unlock; 1015 } 1016 1017 skcipher_request_set_callback(s->skcipher_req, 1018 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 1019 1020 /* The characters in the first block effectively do the job of 1021 * the IV here, so we just use 0's for the IV. Note the 1022 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1023 * >= ECRYPTFS_MAX_IV_BYTES. */ 1024 /* TODO: Support other key modules than passphrase for 1025 * filename encryption */ 1026 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1027 rc = -EOPNOTSUPP; 1028 printk(KERN_INFO "%s: Filename encryption only supports " 1029 "password tokens\n", __func__); 1030 goto out_free_unlock; 1031 } 1032 rc = crypto_skcipher_setkey( 1033 s->skcipher_tfm, 1034 s->auth_tok->token.password.session_key_encryption_key, 1035 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1036 if (rc < 0) { 1037 printk(KERN_ERR "%s: Error setting key for crypto context; " 1038 "rc = [%d]. s->auth_tok->token.password.session_key_" 1039 "encryption_key = [0x%p]; mount_crypt_stat->" 1040 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1041 rc, 1042 s->auth_tok->token.password.session_key_encryption_key, 1043 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1044 goto out_free_unlock; 1045 } 1046 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 1047 s->block_aligned_filename_size, s->iv); 1048 rc = crypto_skcipher_decrypt(s->skcipher_req); 1049 if (rc) { 1050 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1051 "rc = [%d]\n", __func__, rc); 1052 goto out_free_unlock; 1053 } 1054 1055 while (s->i < s->block_aligned_filename_size && 1056 s->decrypted_filename[s->i] != '\0') 1057 s->i++; 1058 if (s->i == s->block_aligned_filename_size) { 1059 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1060 "find valid separator between random characters and " 1061 "the filename\n", __func__); 1062 rc = -EINVAL; 1063 goto out_free_unlock; 1064 } 1065 s->i++; 1066 (*filename_size) = (s->block_aligned_filename_size - s->i); 1067 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1068 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1069 "invalid\n", __func__, (*filename_size)); 1070 rc = -EINVAL; 1071 goto out_free_unlock; 1072 } 1073 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1074 if (!(*filename)) { 1075 rc = -ENOMEM; 1076 goto out_free_unlock; 1077 } 1078 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1079 (*filename)[(*filename_size)] = '\0'; 1080 out_free_unlock: 1081 kfree(s->decrypted_filename); 1082 out_unlock: 1083 mutex_unlock(s->tfm_mutex); 1084 out: 1085 if (rc) { 1086 (*packet_size) = 0; 1087 (*filename_size) = 0; 1088 (*filename) = NULL; 1089 } 1090 if (auth_tok_key) { 1091 up_write(&(auth_tok_key->sem)); 1092 key_put(auth_tok_key); 1093 } 1094 skcipher_request_free(s->skcipher_req); 1095 kfree(s); 1096 return rc; 1097 } 1098 1099 static int 1100 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1101 { 1102 int rc = 0; 1103 1104 (*sig) = NULL; 1105 switch (auth_tok->token_type) { 1106 case ECRYPTFS_PASSWORD: 1107 (*sig) = auth_tok->token.password.signature; 1108 break; 1109 case ECRYPTFS_PRIVATE_KEY: 1110 (*sig) = auth_tok->token.private_key.signature; 1111 break; 1112 default: 1113 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1114 auth_tok->token_type); 1115 rc = -EINVAL; 1116 } 1117 return rc; 1118 } 1119 1120 /** 1121 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1122 * @auth_tok: The key authentication token used to decrypt the session key 1123 * @crypt_stat: The cryptographic context 1124 * 1125 * Returns zero on success; non-zero error otherwise. 1126 */ 1127 static int 1128 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1129 struct ecryptfs_crypt_stat *crypt_stat) 1130 { 1131 u8 cipher_code = 0; 1132 struct ecryptfs_msg_ctx *msg_ctx; 1133 struct ecryptfs_message *msg = NULL; 1134 char *auth_tok_sig; 1135 char *payload = NULL; 1136 size_t payload_len = 0; 1137 int rc; 1138 1139 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1140 if (rc) { 1141 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1142 auth_tok->token_type); 1143 goto out; 1144 } 1145 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1146 &payload, &payload_len); 1147 if (rc) { 1148 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1149 goto out; 1150 } 1151 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1152 if (rc) { 1153 ecryptfs_printk(KERN_ERR, "Error sending message to " 1154 "ecryptfsd: %d\n", rc); 1155 goto out; 1156 } 1157 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1158 if (rc) { 1159 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1160 "from the user space daemon\n"); 1161 rc = -EIO; 1162 goto out; 1163 } 1164 rc = parse_tag_65_packet(&(auth_tok->session_key), 1165 &cipher_code, msg); 1166 if (rc) { 1167 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1168 rc); 1169 goto out; 1170 } 1171 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1172 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1173 auth_tok->session_key.decrypted_key_size); 1174 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1175 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1176 if (rc) { 1177 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1178 cipher_code); 1179 goto out; 1180 } 1181 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1182 if (ecryptfs_verbosity > 0) { 1183 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1184 ecryptfs_dump_hex(crypt_stat->key, 1185 crypt_stat->key_size); 1186 } 1187 out: 1188 kfree(msg); 1189 kfree(payload); 1190 return rc; 1191 } 1192 1193 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1194 { 1195 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1196 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1197 1198 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1199 auth_tok_list_head, list) { 1200 list_del(&auth_tok_list_item->list); 1201 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1202 auth_tok_list_item); 1203 } 1204 } 1205 1206 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1207 1208 /** 1209 * parse_tag_1_packet 1210 * @crypt_stat: The cryptographic context to modify based on packet contents 1211 * @data: The raw bytes of the packet. 1212 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1213 * a new authentication token will be placed at the 1214 * end of this list for this packet. 1215 * @new_auth_tok: Pointer to a pointer to memory that this function 1216 * allocates; sets the memory address of the pointer to 1217 * NULL on error. This object is added to the 1218 * auth_tok_list. 1219 * @packet_size: This function writes the size of the parsed packet 1220 * into this memory location; zero on error. 1221 * @max_packet_size: The maximum allowable packet size 1222 * 1223 * Returns zero on success; non-zero on error. 1224 */ 1225 static int 1226 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1227 unsigned char *data, struct list_head *auth_tok_list, 1228 struct ecryptfs_auth_tok **new_auth_tok, 1229 size_t *packet_size, size_t max_packet_size) 1230 { 1231 size_t body_size; 1232 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1233 size_t length_size; 1234 int rc = 0; 1235 1236 (*packet_size) = 0; 1237 (*new_auth_tok) = NULL; 1238 /** 1239 * This format is inspired by OpenPGP; see RFC 2440 1240 * packet tag 1 1241 * 1242 * Tag 1 identifier (1 byte) 1243 * Max Tag 1 packet size (max 3 bytes) 1244 * Version (1 byte) 1245 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1246 * Cipher identifier (1 byte) 1247 * Encrypted key size (arbitrary) 1248 * 1249 * 12 bytes minimum packet size 1250 */ 1251 if (unlikely(max_packet_size < 12)) { 1252 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1253 rc = -EINVAL; 1254 goto out; 1255 } 1256 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1257 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1258 ECRYPTFS_TAG_1_PACKET_TYPE); 1259 rc = -EINVAL; 1260 goto out; 1261 } 1262 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1263 * at end of function upon failure */ 1264 auth_tok_list_item = 1265 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1266 GFP_KERNEL); 1267 if (!auth_tok_list_item) { 1268 printk(KERN_ERR "Unable to allocate memory\n"); 1269 rc = -ENOMEM; 1270 goto out; 1271 } 1272 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1273 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1274 &length_size); 1275 if (rc) { 1276 printk(KERN_WARNING "Error parsing packet length; " 1277 "rc = [%d]\n", rc); 1278 goto out_free; 1279 } 1280 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1281 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1282 rc = -EINVAL; 1283 goto out_free; 1284 } 1285 (*packet_size) += length_size; 1286 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1287 printk(KERN_WARNING "Packet size exceeds max\n"); 1288 rc = -EINVAL; 1289 goto out_free; 1290 } 1291 if (unlikely(data[(*packet_size)++] != 0x03)) { 1292 printk(KERN_WARNING "Unknown version number [%d]\n", 1293 data[(*packet_size) - 1]); 1294 rc = -EINVAL; 1295 goto out_free; 1296 } 1297 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1298 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1299 *packet_size += ECRYPTFS_SIG_SIZE; 1300 /* This byte is skipped because the kernel does not need to 1301 * know which public key encryption algorithm was used */ 1302 (*packet_size)++; 1303 (*new_auth_tok)->session_key.encrypted_key_size = 1304 body_size - (ECRYPTFS_SIG_SIZE + 2); 1305 if ((*new_auth_tok)->session_key.encrypted_key_size 1306 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1307 printk(KERN_WARNING "Tag 1 packet contains key larger " 1308 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1309 rc = -EINVAL; 1310 goto out_free; 1311 } 1312 memcpy((*new_auth_tok)->session_key.encrypted_key, 1313 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1314 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1315 (*new_auth_tok)->session_key.flags &= 1316 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1317 (*new_auth_tok)->session_key.flags |= 1318 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1319 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1320 (*new_auth_tok)->flags = 0; 1321 (*new_auth_tok)->session_key.flags &= 1322 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1323 (*new_auth_tok)->session_key.flags &= 1324 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1325 list_add(&auth_tok_list_item->list, auth_tok_list); 1326 goto out; 1327 out_free: 1328 (*new_auth_tok) = NULL; 1329 memset(auth_tok_list_item, 0, 1330 sizeof(struct ecryptfs_auth_tok_list_item)); 1331 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1332 auth_tok_list_item); 1333 out: 1334 if (rc) 1335 (*packet_size) = 0; 1336 return rc; 1337 } 1338 1339 /** 1340 * parse_tag_3_packet 1341 * @crypt_stat: The cryptographic context to modify based on packet 1342 * contents. 1343 * @data: The raw bytes of the packet. 1344 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1345 * a new authentication token will be placed at the end 1346 * of this list for this packet. 1347 * @new_auth_tok: Pointer to a pointer to memory that this function 1348 * allocates; sets the memory address of the pointer to 1349 * NULL on error. This object is added to the 1350 * auth_tok_list. 1351 * @packet_size: This function writes the size of the parsed packet 1352 * into this memory location; zero on error. 1353 * @max_packet_size: maximum number of bytes to parse 1354 * 1355 * Returns zero on success; non-zero on error. 1356 */ 1357 static int 1358 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1359 unsigned char *data, struct list_head *auth_tok_list, 1360 struct ecryptfs_auth_tok **new_auth_tok, 1361 size_t *packet_size, size_t max_packet_size) 1362 { 1363 size_t body_size; 1364 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1365 size_t length_size; 1366 int rc = 0; 1367 1368 (*packet_size) = 0; 1369 (*new_auth_tok) = NULL; 1370 /** 1371 *This format is inspired by OpenPGP; see RFC 2440 1372 * packet tag 3 1373 * 1374 * Tag 3 identifier (1 byte) 1375 * Max Tag 3 packet size (max 3 bytes) 1376 * Version (1 byte) 1377 * Cipher code (1 byte) 1378 * S2K specifier (1 byte) 1379 * Hash identifier (1 byte) 1380 * Salt (ECRYPTFS_SALT_SIZE) 1381 * Hash iterations (1 byte) 1382 * Encrypted key (arbitrary) 1383 * 1384 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1385 */ 1386 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1387 printk(KERN_ERR "Max packet size too large\n"); 1388 rc = -EINVAL; 1389 goto out; 1390 } 1391 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1392 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1393 ECRYPTFS_TAG_3_PACKET_TYPE); 1394 rc = -EINVAL; 1395 goto out; 1396 } 1397 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1398 * at end of function upon failure */ 1399 auth_tok_list_item = 1400 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1401 if (!auth_tok_list_item) { 1402 printk(KERN_ERR "Unable to allocate memory\n"); 1403 rc = -ENOMEM; 1404 goto out; 1405 } 1406 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1407 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1408 &length_size); 1409 if (rc) { 1410 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1411 rc); 1412 goto out_free; 1413 } 1414 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1415 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1416 rc = -EINVAL; 1417 goto out_free; 1418 } 1419 (*packet_size) += length_size; 1420 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1421 printk(KERN_ERR "Packet size exceeds max\n"); 1422 rc = -EINVAL; 1423 goto out_free; 1424 } 1425 (*new_auth_tok)->session_key.encrypted_key_size = 1426 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1427 if ((*new_auth_tok)->session_key.encrypted_key_size 1428 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1429 printk(KERN_WARNING "Tag 3 packet contains key larger " 1430 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1431 rc = -EINVAL; 1432 goto out_free; 1433 } 1434 if (unlikely(data[(*packet_size)++] != 0x04)) { 1435 printk(KERN_WARNING "Unknown version number [%d]\n", 1436 data[(*packet_size) - 1]); 1437 rc = -EINVAL; 1438 goto out_free; 1439 } 1440 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1441 (u16)data[(*packet_size)]); 1442 if (rc) 1443 goto out_free; 1444 /* A little extra work to differentiate among the AES key 1445 * sizes; see RFC2440 */ 1446 switch(data[(*packet_size)++]) { 1447 case RFC2440_CIPHER_AES_192: 1448 crypt_stat->key_size = 24; 1449 break; 1450 default: 1451 crypt_stat->key_size = 1452 (*new_auth_tok)->session_key.encrypted_key_size; 1453 } 1454 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1455 if (rc) 1456 goto out_free; 1457 if (unlikely(data[(*packet_size)++] != 0x03)) { 1458 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1459 rc = -ENOSYS; 1460 goto out_free; 1461 } 1462 /* TODO: finish the hash mapping */ 1463 switch (data[(*packet_size)++]) { 1464 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1465 /* Choose MD5 */ 1466 memcpy((*new_auth_tok)->token.password.salt, 1467 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1468 (*packet_size) += ECRYPTFS_SALT_SIZE; 1469 /* This conversion was taken straight from RFC2440 */ 1470 (*new_auth_tok)->token.password.hash_iterations = 1471 ((u32) 16 + (data[(*packet_size)] & 15)) 1472 << ((data[(*packet_size)] >> 4) + 6); 1473 (*packet_size)++; 1474 /* Friendly reminder: 1475 * (*new_auth_tok)->session_key.encrypted_key_size = 1476 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1477 memcpy((*new_auth_tok)->session_key.encrypted_key, 1478 &data[(*packet_size)], 1479 (*new_auth_tok)->session_key.encrypted_key_size); 1480 (*packet_size) += 1481 (*new_auth_tok)->session_key.encrypted_key_size; 1482 (*new_auth_tok)->session_key.flags &= 1483 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1484 (*new_auth_tok)->session_key.flags |= 1485 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1486 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1487 break; 1488 default: 1489 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1490 "[%d]\n", data[(*packet_size) - 1]); 1491 rc = -ENOSYS; 1492 goto out_free; 1493 } 1494 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1495 /* TODO: Parametarize; we might actually want userspace to 1496 * decrypt the session key. */ 1497 (*new_auth_tok)->session_key.flags &= 1498 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1499 (*new_auth_tok)->session_key.flags &= 1500 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1501 list_add(&auth_tok_list_item->list, auth_tok_list); 1502 goto out; 1503 out_free: 1504 (*new_auth_tok) = NULL; 1505 memset(auth_tok_list_item, 0, 1506 sizeof(struct ecryptfs_auth_tok_list_item)); 1507 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1508 auth_tok_list_item); 1509 out: 1510 if (rc) 1511 (*packet_size) = 0; 1512 return rc; 1513 } 1514 1515 /** 1516 * parse_tag_11_packet 1517 * @data: The raw bytes of the packet 1518 * @contents: This function writes the data contents of the literal 1519 * packet into this memory location 1520 * @max_contents_bytes: The maximum number of bytes that this function 1521 * is allowed to write into contents 1522 * @tag_11_contents_size: This function writes the size of the parsed 1523 * contents into this memory location; zero on 1524 * error 1525 * @packet_size: This function writes the size of the parsed packet 1526 * into this memory location; zero on error 1527 * @max_packet_size: maximum number of bytes to parse 1528 * 1529 * Returns zero on success; non-zero on error. 1530 */ 1531 static int 1532 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1533 size_t max_contents_bytes, size_t *tag_11_contents_size, 1534 size_t *packet_size, size_t max_packet_size) 1535 { 1536 size_t body_size; 1537 size_t length_size; 1538 int rc = 0; 1539 1540 (*packet_size) = 0; 1541 (*tag_11_contents_size) = 0; 1542 /* This format is inspired by OpenPGP; see RFC 2440 1543 * packet tag 11 1544 * 1545 * Tag 11 identifier (1 byte) 1546 * Max Tag 11 packet size (max 3 bytes) 1547 * Binary format specifier (1 byte) 1548 * Filename length (1 byte) 1549 * Filename ("_CONSOLE") (8 bytes) 1550 * Modification date (4 bytes) 1551 * Literal data (arbitrary) 1552 * 1553 * We need at least 16 bytes of data for the packet to even be 1554 * valid. 1555 */ 1556 if (max_packet_size < 16) { 1557 printk(KERN_ERR "Maximum packet size too small\n"); 1558 rc = -EINVAL; 1559 goto out; 1560 } 1561 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1562 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1563 rc = -EINVAL; 1564 goto out; 1565 } 1566 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1567 &length_size); 1568 if (rc) { 1569 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1570 goto out; 1571 } 1572 if (body_size < 14) { 1573 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1574 rc = -EINVAL; 1575 goto out; 1576 } 1577 (*packet_size) += length_size; 1578 (*tag_11_contents_size) = (body_size - 14); 1579 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1580 printk(KERN_ERR "Packet size exceeds max\n"); 1581 rc = -EINVAL; 1582 goto out; 1583 } 1584 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1585 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1586 "expected size\n"); 1587 rc = -EINVAL; 1588 goto out; 1589 } 1590 if (data[(*packet_size)++] != 0x62) { 1591 printk(KERN_WARNING "Unrecognizable packet\n"); 1592 rc = -EINVAL; 1593 goto out; 1594 } 1595 if (data[(*packet_size)++] != 0x08) { 1596 printk(KERN_WARNING "Unrecognizable packet\n"); 1597 rc = -EINVAL; 1598 goto out; 1599 } 1600 (*packet_size) += 12; /* Ignore filename and modification date */ 1601 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1602 (*packet_size) += (*tag_11_contents_size); 1603 out: 1604 if (rc) { 1605 (*packet_size) = 0; 1606 (*tag_11_contents_size) = 0; 1607 } 1608 return rc; 1609 } 1610 1611 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1612 struct ecryptfs_auth_tok **auth_tok, 1613 char *sig) 1614 { 1615 int rc = 0; 1616 1617 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1618 if (IS_ERR(*auth_tok_key)) { 1619 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1620 if (IS_ERR(*auth_tok_key)) { 1621 printk(KERN_ERR "Could not find key with description: [%s]\n", 1622 sig); 1623 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1624 (*auth_tok_key) = NULL; 1625 goto out; 1626 } 1627 } 1628 down_write(&(*auth_tok_key)->sem); 1629 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1630 if (rc) { 1631 up_write(&(*auth_tok_key)->sem); 1632 key_put(*auth_tok_key); 1633 (*auth_tok_key) = NULL; 1634 goto out; 1635 } 1636 out: 1637 return rc; 1638 } 1639 1640 /** 1641 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1642 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1643 * @crypt_stat: The cryptographic context 1644 * 1645 * Returns zero on success; non-zero error otherwise 1646 */ 1647 static int 1648 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1649 struct ecryptfs_crypt_stat *crypt_stat) 1650 { 1651 struct scatterlist dst_sg[2]; 1652 struct scatterlist src_sg[2]; 1653 struct mutex *tfm_mutex; 1654 struct crypto_skcipher *tfm; 1655 struct skcipher_request *req = NULL; 1656 int rc = 0; 1657 1658 if (unlikely(ecryptfs_verbosity > 0)) { 1659 ecryptfs_printk( 1660 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1661 auth_tok->token.password.session_key_encryption_key_bytes); 1662 ecryptfs_dump_hex( 1663 auth_tok->token.password.session_key_encryption_key, 1664 auth_tok->token.password.session_key_encryption_key_bytes); 1665 } 1666 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 1667 crypt_stat->cipher); 1668 if (unlikely(rc)) { 1669 printk(KERN_ERR "Internal error whilst attempting to get " 1670 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1671 crypt_stat->cipher, rc); 1672 goto out; 1673 } 1674 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1675 auth_tok->session_key.encrypted_key_size, 1676 src_sg, 2); 1677 if (rc < 1 || rc > 2) { 1678 printk(KERN_ERR "Internal error whilst attempting to convert " 1679 "auth_tok->session_key.encrypted_key to scatterlist; " 1680 "expected rc = 1; got rc = [%d]. " 1681 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1682 auth_tok->session_key.encrypted_key_size); 1683 goto out; 1684 } 1685 auth_tok->session_key.decrypted_key_size = 1686 auth_tok->session_key.encrypted_key_size; 1687 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1688 auth_tok->session_key.decrypted_key_size, 1689 dst_sg, 2); 1690 if (rc < 1 || rc > 2) { 1691 printk(KERN_ERR "Internal error whilst attempting to convert " 1692 "auth_tok->session_key.decrypted_key to scatterlist; " 1693 "expected rc = 1; got rc = [%d]\n", rc); 1694 goto out; 1695 } 1696 mutex_lock(tfm_mutex); 1697 req = skcipher_request_alloc(tfm, GFP_KERNEL); 1698 if (!req) { 1699 mutex_unlock(tfm_mutex); 1700 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1701 "skcipher_request_alloc for %s\n", __func__, 1702 crypto_skcipher_driver_name(tfm)); 1703 rc = -ENOMEM; 1704 goto out; 1705 } 1706 1707 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 1708 NULL, NULL); 1709 rc = crypto_skcipher_setkey( 1710 tfm, auth_tok->token.password.session_key_encryption_key, 1711 crypt_stat->key_size); 1712 if (unlikely(rc < 0)) { 1713 mutex_unlock(tfm_mutex); 1714 printk(KERN_ERR "Error setting key for crypto context\n"); 1715 rc = -EINVAL; 1716 goto out; 1717 } 1718 skcipher_request_set_crypt(req, src_sg, dst_sg, 1719 auth_tok->session_key.encrypted_key_size, 1720 NULL); 1721 rc = crypto_skcipher_decrypt(req); 1722 mutex_unlock(tfm_mutex); 1723 if (unlikely(rc)) { 1724 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1725 goto out; 1726 } 1727 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1728 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1729 auth_tok->session_key.decrypted_key_size); 1730 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1731 if (unlikely(ecryptfs_verbosity > 0)) { 1732 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1733 crypt_stat->key_size); 1734 ecryptfs_dump_hex(crypt_stat->key, 1735 crypt_stat->key_size); 1736 } 1737 out: 1738 skcipher_request_free(req); 1739 return rc; 1740 } 1741 1742 /** 1743 * ecryptfs_parse_packet_set 1744 * @crypt_stat: The cryptographic context 1745 * @src: Virtual address of region of memory containing the packets 1746 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1747 * 1748 * Get crypt_stat to have the file's session key if the requisite key 1749 * is available to decrypt the session key. 1750 * 1751 * Returns Zero if a valid authentication token was retrieved and 1752 * processed; negative value for file not encrypted or for error 1753 * conditions. 1754 */ 1755 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1756 unsigned char *src, 1757 struct dentry *ecryptfs_dentry) 1758 { 1759 size_t i = 0; 1760 size_t found_auth_tok; 1761 size_t next_packet_is_auth_tok_packet; 1762 struct list_head auth_tok_list; 1763 struct ecryptfs_auth_tok *matching_auth_tok; 1764 struct ecryptfs_auth_tok *candidate_auth_tok; 1765 char *candidate_auth_tok_sig; 1766 size_t packet_size; 1767 struct ecryptfs_auth_tok *new_auth_tok; 1768 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1769 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1770 size_t tag_11_contents_size; 1771 size_t tag_11_packet_size; 1772 struct key *auth_tok_key = NULL; 1773 int rc = 0; 1774 1775 INIT_LIST_HEAD(&auth_tok_list); 1776 /* Parse the header to find as many packets as we can; these will be 1777 * added the our &auth_tok_list */ 1778 next_packet_is_auth_tok_packet = 1; 1779 while (next_packet_is_auth_tok_packet) { 1780 size_t max_packet_size = ((PAGE_SIZE - 8) - i); 1781 1782 switch (src[i]) { 1783 case ECRYPTFS_TAG_3_PACKET_TYPE: 1784 rc = parse_tag_3_packet(crypt_stat, 1785 (unsigned char *)&src[i], 1786 &auth_tok_list, &new_auth_tok, 1787 &packet_size, max_packet_size); 1788 if (rc) { 1789 ecryptfs_printk(KERN_ERR, "Error parsing " 1790 "tag 3 packet\n"); 1791 rc = -EIO; 1792 goto out_wipe_list; 1793 } 1794 i += packet_size; 1795 rc = parse_tag_11_packet((unsigned char *)&src[i], 1796 sig_tmp_space, 1797 ECRYPTFS_SIG_SIZE, 1798 &tag_11_contents_size, 1799 &tag_11_packet_size, 1800 max_packet_size); 1801 if (rc) { 1802 ecryptfs_printk(KERN_ERR, "No valid " 1803 "(ecryptfs-specific) literal " 1804 "packet containing " 1805 "authentication token " 1806 "signature found after " 1807 "tag 3 packet\n"); 1808 rc = -EIO; 1809 goto out_wipe_list; 1810 } 1811 i += tag_11_packet_size; 1812 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1813 ecryptfs_printk(KERN_ERR, "Expected " 1814 "signature of size [%d]; " 1815 "read size [%zd]\n", 1816 ECRYPTFS_SIG_SIZE, 1817 tag_11_contents_size); 1818 rc = -EIO; 1819 goto out_wipe_list; 1820 } 1821 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1822 sig_tmp_space, tag_11_contents_size); 1823 new_auth_tok->token.password.signature[ 1824 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1825 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1826 break; 1827 case ECRYPTFS_TAG_1_PACKET_TYPE: 1828 rc = parse_tag_1_packet(crypt_stat, 1829 (unsigned char *)&src[i], 1830 &auth_tok_list, &new_auth_tok, 1831 &packet_size, max_packet_size); 1832 if (rc) { 1833 ecryptfs_printk(KERN_ERR, "Error parsing " 1834 "tag 1 packet\n"); 1835 rc = -EIO; 1836 goto out_wipe_list; 1837 } 1838 i += packet_size; 1839 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1840 break; 1841 case ECRYPTFS_TAG_11_PACKET_TYPE: 1842 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1843 "(Tag 11 not allowed by itself)\n"); 1844 rc = -EIO; 1845 goto out_wipe_list; 1846 default: 1847 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1848 "of the file header; hex value of " 1849 "character is [0x%.2x]\n", i, src[i]); 1850 next_packet_is_auth_tok_packet = 0; 1851 } 1852 } 1853 if (list_empty(&auth_tok_list)) { 1854 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1855 "eCryptfs file; this is not supported in this version " 1856 "of the eCryptfs kernel module\n"); 1857 rc = -EINVAL; 1858 goto out; 1859 } 1860 /* auth_tok_list contains the set of authentication tokens 1861 * parsed from the metadata. We need to find a matching 1862 * authentication token that has the secret component(s) 1863 * necessary to decrypt the EFEK in the auth_tok parsed from 1864 * the metadata. There may be several potential matches, but 1865 * just one will be sufficient to decrypt to get the FEK. */ 1866 find_next_matching_auth_tok: 1867 found_auth_tok = 0; 1868 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1869 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1870 if (unlikely(ecryptfs_verbosity > 0)) { 1871 ecryptfs_printk(KERN_DEBUG, 1872 "Considering candidate auth tok:\n"); 1873 ecryptfs_dump_auth_tok(candidate_auth_tok); 1874 } 1875 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1876 candidate_auth_tok); 1877 if (rc) { 1878 printk(KERN_ERR 1879 "Unrecognized candidate auth tok type: [%d]\n", 1880 candidate_auth_tok->token_type); 1881 rc = -EINVAL; 1882 goto out_wipe_list; 1883 } 1884 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1885 &matching_auth_tok, 1886 crypt_stat->mount_crypt_stat, 1887 candidate_auth_tok_sig); 1888 if (!rc) { 1889 found_auth_tok = 1; 1890 goto found_matching_auth_tok; 1891 } 1892 } 1893 if (!found_auth_tok) { 1894 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1895 "authentication token\n"); 1896 rc = -EIO; 1897 goto out_wipe_list; 1898 } 1899 found_matching_auth_tok: 1900 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1901 memcpy(&(candidate_auth_tok->token.private_key), 1902 &(matching_auth_tok->token.private_key), 1903 sizeof(struct ecryptfs_private_key)); 1904 up_write(&(auth_tok_key->sem)); 1905 key_put(auth_tok_key); 1906 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1907 crypt_stat); 1908 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1909 memcpy(&(candidate_auth_tok->token.password), 1910 &(matching_auth_tok->token.password), 1911 sizeof(struct ecryptfs_password)); 1912 up_write(&(auth_tok_key->sem)); 1913 key_put(auth_tok_key); 1914 rc = decrypt_passphrase_encrypted_session_key( 1915 candidate_auth_tok, crypt_stat); 1916 } else { 1917 up_write(&(auth_tok_key->sem)); 1918 key_put(auth_tok_key); 1919 rc = -EINVAL; 1920 } 1921 if (rc) { 1922 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1923 1924 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1925 "session key for authentication token with sig " 1926 "[%.*s]; rc = [%d]. Removing auth tok " 1927 "candidate from the list and searching for " 1928 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1929 candidate_auth_tok_sig, rc); 1930 list_for_each_entry_safe(auth_tok_list_item, 1931 auth_tok_list_item_tmp, 1932 &auth_tok_list, list) { 1933 if (candidate_auth_tok 1934 == &auth_tok_list_item->auth_tok) { 1935 list_del(&auth_tok_list_item->list); 1936 kmem_cache_free( 1937 ecryptfs_auth_tok_list_item_cache, 1938 auth_tok_list_item); 1939 goto find_next_matching_auth_tok; 1940 } 1941 } 1942 BUG(); 1943 } 1944 rc = ecryptfs_compute_root_iv(crypt_stat); 1945 if (rc) { 1946 ecryptfs_printk(KERN_ERR, "Error computing " 1947 "the root IV\n"); 1948 goto out_wipe_list; 1949 } 1950 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1951 if (rc) { 1952 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1953 "context for cipher [%s]; rc = [%d]\n", 1954 crypt_stat->cipher, rc); 1955 } 1956 out_wipe_list: 1957 wipe_auth_tok_list(&auth_tok_list); 1958 out: 1959 return rc; 1960 } 1961 1962 static int 1963 pki_encrypt_session_key(struct key *auth_tok_key, 1964 struct ecryptfs_auth_tok *auth_tok, 1965 struct ecryptfs_crypt_stat *crypt_stat, 1966 struct ecryptfs_key_record *key_rec) 1967 { 1968 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1969 char *payload = NULL; 1970 size_t payload_len = 0; 1971 struct ecryptfs_message *msg; 1972 int rc; 1973 1974 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1975 ecryptfs_code_for_cipher_string( 1976 crypt_stat->cipher, 1977 crypt_stat->key_size), 1978 crypt_stat, &payload, &payload_len); 1979 up_write(&(auth_tok_key->sem)); 1980 key_put(auth_tok_key); 1981 if (rc) { 1982 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1983 goto out; 1984 } 1985 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1986 if (rc) { 1987 ecryptfs_printk(KERN_ERR, "Error sending message to " 1988 "ecryptfsd: %d\n", rc); 1989 goto out; 1990 } 1991 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1992 if (rc) { 1993 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 1994 "from the user space daemon\n"); 1995 rc = -EIO; 1996 goto out; 1997 } 1998 rc = parse_tag_67_packet(key_rec, msg); 1999 if (rc) 2000 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2001 kfree(msg); 2002 out: 2003 kfree(payload); 2004 return rc; 2005 } 2006 /** 2007 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2008 * @dest: Buffer into which to write the packet 2009 * @remaining_bytes: Maximum number of bytes that can be writtn 2010 * @auth_tok_key: The authentication token key to unlock and put when done with 2011 * @auth_tok 2012 * @auth_tok: The authentication token used for generating the tag 1 packet 2013 * @crypt_stat: The cryptographic context 2014 * @key_rec: The key record struct for the tag 1 packet 2015 * @packet_size: This function will write the number of bytes that end 2016 * up constituting the packet; set to zero on error 2017 * 2018 * Returns zero on success; non-zero on error. 2019 */ 2020 static int 2021 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2022 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2023 struct ecryptfs_crypt_stat *crypt_stat, 2024 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2025 { 2026 size_t i; 2027 size_t encrypted_session_key_valid = 0; 2028 size_t packet_size_length; 2029 size_t max_packet_size; 2030 int rc = 0; 2031 2032 (*packet_size) = 0; 2033 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2034 ECRYPTFS_SIG_SIZE); 2035 encrypted_session_key_valid = 0; 2036 for (i = 0; i < crypt_stat->key_size; i++) 2037 encrypted_session_key_valid |= 2038 auth_tok->session_key.encrypted_key[i]; 2039 if (encrypted_session_key_valid) { 2040 memcpy(key_rec->enc_key, 2041 auth_tok->session_key.encrypted_key, 2042 auth_tok->session_key.encrypted_key_size); 2043 up_write(&(auth_tok_key->sem)); 2044 key_put(auth_tok_key); 2045 goto encrypted_session_key_set; 2046 } 2047 if (auth_tok->session_key.encrypted_key_size == 0) 2048 auth_tok->session_key.encrypted_key_size = 2049 auth_tok->token.private_key.key_size; 2050 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2051 key_rec); 2052 if (rc) { 2053 printk(KERN_ERR "Failed to encrypt session key via a key " 2054 "module; rc = [%d]\n", rc); 2055 goto out; 2056 } 2057 if (ecryptfs_verbosity > 0) { 2058 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2059 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2060 } 2061 encrypted_session_key_set: 2062 /* This format is inspired by OpenPGP; see RFC 2440 2063 * packet tag 1 */ 2064 max_packet_size = (1 /* Tag 1 identifier */ 2065 + 3 /* Max Tag 1 packet size */ 2066 + 1 /* Version */ 2067 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2068 + 1 /* Cipher identifier */ 2069 + key_rec->enc_key_size); /* Encrypted key size */ 2070 if (max_packet_size > (*remaining_bytes)) { 2071 printk(KERN_ERR "Packet length larger than maximum allowable; " 2072 "need up to [%td] bytes, but there are only [%td] " 2073 "available\n", max_packet_size, (*remaining_bytes)); 2074 rc = -EINVAL; 2075 goto out; 2076 } 2077 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2078 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2079 (max_packet_size - 4), 2080 &packet_size_length); 2081 if (rc) { 2082 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2083 "header; cannot generate packet length\n"); 2084 goto out; 2085 } 2086 (*packet_size) += packet_size_length; 2087 dest[(*packet_size)++] = 0x03; /* version 3 */ 2088 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2089 (*packet_size) += ECRYPTFS_SIG_SIZE; 2090 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2091 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2092 key_rec->enc_key_size); 2093 (*packet_size) += key_rec->enc_key_size; 2094 out: 2095 if (rc) 2096 (*packet_size) = 0; 2097 else 2098 (*remaining_bytes) -= (*packet_size); 2099 return rc; 2100 } 2101 2102 /** 2103 * write_tag_11_packet 2104 * @dest: Target into which Tag 11 packet is to be written 2105 * @remaining_bytes: Maximum packet length 2106 * @contents: Byte array of contents to copy in 2107 * @contents_length: Number of bytes in contents 2108 * @packet_length: Length of the Tag 11 packet written; zero on error 2109 * 2110 * Returns zero on success; non-zero on error. 2111 */ 2112 static int 2113 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2114 size_t contents_length, size_t *packet_length) 2115 { 2116 size_t packet_size_length; 2117 size_t max_packet_size; 2118 int rc = 0; 2119 2120 (*packet_length) = 0; 2121 /* This format is inspired by OpenPGP; see RFC 2440 2122 * packet tag 11 */ 2123 max_packet_size = (1 /* Tag 11 identifier */ 2124 + 3 /* Max Tag 11 packet size */ 2125 + 1 /* Binary format specifier */ 2126 + 1 /* Filename length */ 2127 + 8 /* Filename ("_CONSOLE") */ 2128 + 4 /* Modification date */ 2129 + contents_length); /* Literal data */ 2130 if (max_packet_size > (*remaining_bytes)) { 2131 printk(KERN_ERR "Packet length larger than maximum allowable; " 2132 "need up to [%td] bytes, but there are only [%td] " 2133 "available\n", max_packet_size, (*remaining_bytes)); 2134 rc = -EINVAL; 2135 goto out; 2136 } 2137 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2138 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2139 (max_packet_size - 4), 2140 &packet_size_length); 2141 if (rc) { 2142 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2143 "generate packet length. rc = [%d]\n", rc); 2144 goto out; 2145 } 2146 (*packet_length) += packet_size_length; 2147 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2148 dest[(*packet_length)++] = 8; 2149 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2150 (*packet_length) += 8; 2151 memset(&dest[(*packet_length)], 0x00, 4); 2152 (*packet_length) += 4; 2153 memcpy(&dest[(*packet_length)], contents, contents_length); 2154 (*packet_length) += contents_length; 2155 out: 2156 if (rc) 2157 (*packet_length) = 0; 2158 else 2159 (*remaining_bytes) -= (*packet_length); 2160 return rc; 2161 } 2162 2163 /** 2164 * write_tag_3_packet 2165 * @dest: Buffer into which to write the packet 2166 * @remaining_bytes: Maximum number of bytes that can be written 2167 * @auth_tok: Authentication token 2168 * @crypt_stat: The cryptographic context 2169 * @key_rec: encrypted key 2170 * @packet_size: This function will write the number of bytes that end 2171 * up constituting the packet; set to zero on error 2172 * 2173 * Returns zero on success; non-zero on error. 2174 */ 2175 static int 2176 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2177 struct ecryptfs_auth_tok *auth_tok, 2178 struct ecryptfs_crypt_stat *crypt_stat, 2179 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2180 { 2181 size_t i; 2182 size_t encrypted_session_key_valid = 0; 2183 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2184 struct scatterlist dst_sg[2]; 2185 struct scatterlist src_sg[2]; 2186 struct mutex *tfm_mutex = NULL; 2187 u8 cipher_code; 2188 size_t packet_size_length; 2189 size_t max_packet_size; 2190 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2191 crypt_stat->mount_crypt_stat; 2192 struct crypto_skcipher *tfm; 2193 struct skcipher_request *req; 2194 int rc = 0; 2195 2196 (*packet_size) = 0; 2197 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2198 ECRYPTFS_SIG_SIZE); 2199 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 2200 crypt_stat->cipher); 2201 if (unlikely(rc)) { 2202 printk(KERN_ERR "Internal error whilst attempting to get " 2203 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2204 crypt_stat->cipher, rc); 2205 goto out; 2206 } 2207 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2208 printk(KERN_WARNING "No key size specified at mount; " 2209 "defaulting to [%d]\n", 2210 crypto_skcipher_max_keysize(tfm)); 2211 mount_crypt_stat->global_default_cipher_key_size = 2212 crypto_skcipher_max_keysize(tfm); 2213 } 2214 if (crypt_stat->key_size == 0) 2215 crypt_stat->key_size = 2216 mount_crypt_stat->global_default_cipher_key_size; 2217 if (auth_tok->session_key.encrypted_key_size == 0) 2218 auth_tok->session_key.encrypted_key_size = 2219 crypt_stat->key_size; 2220 if (crypt_stat->key_size == 24 2221 && strcmp("aes", crypt_stat->cipher) == 0) { 2222 memset((crypt_stat->key + 24), 0, 8); 2223 auth_tok->session_key.encrypted_key_size = 32; 2224 } else 2225 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2226 key_rec->enc_key_size = 2227 auth_tok->session_key.encrypted_key_size; 2228 encrypted_session_key_valid = 0; 2229 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2230 encrypted_session_key_valid |= 2231 auth_tok->session_key.encrypted_key[i]; 2232 if (encrypted_session_key_valid) { 2233 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2234 "using auth_tok->session_key.encrypted_key, " 2235 "where key_rec->enc_key_size = [%zd]\n", 2236 key_rec->enc_key_size); 2237 memcpy(key_rec->enc_key, 2238 auth_tok->session_key.encrypted_key, 2239 key_rec->enc_key_size); 2240 goto encrypted_session_key_set; 2241 } 2242 if (auth_tok->token.password.flags & 2243 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2244 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2245 "session key encryption key of size [%d]\n", 2246 auth_tok->token.password. 2247 session_key_encryption_key_bytes); 2248 memcpy(session_key_encryption_key, 2249 auth_tok->token.password.session_key_encryption_key, 2250 crypt_stat->key_size); 2251 ecryptfs_printk(KERN_DEBUG, 2252 "Cached session key encryption key:\n"); 2253 if (ecryptfs_verbosity > 0) 2254 ecryptfs_dump_hex(session_key_encryption_key, 16); 2255 } 2256 if (unlikely(ecryptfs_verbosity > 0)) { 2257 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2258 ecryptfs_dump_hex(session_key_encryption_key, 16); 2259 } 2260 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2261 src_sg, 2); 2262 if (rc < 1 || rc > 2) { 2263 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2264 "for crypt_stat session key; expected rc = 1; " 2265 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2266 rc, key_rec->enc_key_size); 2267 rc = -ENOMEM; 2268 goto out; 2269 } 2270 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2271 dst_sg, 2); 2272 if (rc < 1 || rc > 2) { 2273 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2274 "for crypt_stat encrypted session key; " 2275 "expected rc = 1; got rc = [%d]. " 2276 "key_rec->enc_key_size = [%zd]\n", rc, 2277 key_rec->enc_key_size); 2278 rc = -ENOMEM; 2279 goto out; 2280 } 2281 mutex_lock(tfm_mutex); 2282 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key, 2283 crypt_stat->key_size); 2284 if (rc < 0) { 2285 mutex_unlock(tfm_mutex); 2286 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2287 "context; rc = [%d]\n", rc); 2288 goto out; 2289 } 2290 2291 req = skcipher_request_alloc(tfm, GFP_KERNEL); 2292 if (!req) { 2293 mutex_unlock(tfm_mutex); 2294 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " 2295 "attempting to skcipher_request_alloc for " 2296 "%s\n", crypto_skcipher_driver_name(tfm)); 2297 rc = -ENOMEM; 2298 goto out; 2299 } 2300 2301 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 2302 NULL, NULL); 2303 2304 rc = 0; 2305 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2306 crypt_stat->key_size); 2307 skcipher_request_set_crypt(req, src_sg, dst_sg, 2308 (*key_rec).enc_key_size, NULL); 2309 rc = crypto_skcipher_encrypt(req); 2310 mutex_unlock(tfm_mutex); 2311 skcipher_request_free(req); 2312 if (rc) { 2313 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2314 goto out; 2315 } 2316 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2317 if (ecryptfs_verbosity > 0) { 2318 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2319 key_rec->enc_key_size); 2320 ecryptfs_dump_hex(key_rec->enc_key, 2321 key_rec->enc_key_size); 2322 } 2323 encrypted_session_key_set: 2324 /* This format is inspired by OpenPGP; see RFC 2440 2325 * packet tag 3 */ 2326 max_packet_size = (1 /* Tag 3 identifier */ 2327 + 3 /* Max Tag 3 packet size */ 2328 + 1 /* Version */ 2329 + 1 /* Cipher code */ 2330 + 1 /* S2K specifier */ 2331 + 1 /* Hash identifier */ 2332 + ECRYPTFS_SALT_SIZE /* Salt */ 2333 + 1 /* Hash iterations */ 2334 + key_rec->enc_key_size); /* Encrypted key size */ 2335 if (max_packet_size > (*remaining_bytes)) { 2336 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2337 "there are only [%td] available\n", max_packet_size, 2338 (*remaining_bytes)); 2339 rc = -EINVAL; 2340 goto out; 2341 } 2342 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2343 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2344 * to get the number of octets in the actual Tag 3 packet */ 2345 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2346 (max_packet_size - 4), 2347 &packet_size_length); 2348 if (rc) { 2349 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2350 "generate packet length. rc = [%d]\n", rc); 2351 goto out; 2352 } 2353 (*packet_size) += packet_size_length; 2354 dest[(*packet_size)++] = 0x04; /* version 4 */ 2355 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2356 * specified with strings */ 2357 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2358 crypt_stat->key_size); 2359 if (cipher_code == 0) { 2360 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2361 "cipher [%s]\n", crypt_stat->cipher); 2362 rc = -EINVAL; 2363 goto out; 2364 } 2365 dest[(*packet_size)++] = cipher_code; 2366 dest[(*packet_size)++] = 0x03; /* S2K */ 2367 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2368 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2369 ECRYPTFS_SALT_SIZE); 2370 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2371 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2372 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2373 key_rec->enc_key_size); 2374 (*packet_size) += key_rec->enc_key_size; 2375 out: 2376 if (rc) 2377 (*packet_size) = 0; 2378 else 2379 (*remaining_bytes) -= (*packet_size); 2380 return rc; 2381 } 2382 2383 struct kmem_cache *ecryptfs_key_record_cache; 2384 2385 /** 2386 * ecryptfs_generate_key_packet_set 2387 * @dest_base: Virtual address from which to write the key record set 2388 * @crypt_stat: The cryptographic context from which the 2389 * authentication tokens will be retrieved 2390 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2391 * for the global parameters 2392 * @len: The amount written 2393 * @max: The maximum amount of data allowed to be written 2394 * 2395 * Generates a key packet set and writes it to the virtual address 2396 * passed in. 2397 * 2398 * Returns zero on success; non-zero on error. 2399 */ 2400 int 2401 ecryptfs_generate_key_packet_set(char *dest_base, 2402 struct ecryptfs_crypt_stat *crypt_stat, 2403 struct dentry *ecryptfs_dentry, size_t *len, 2404 size_t max) 2405 { 2406 struct ecryptfs_auth_tok *auth_tok; 2407 struct key *auth_tok_key = NULL; 2408 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2409 &ecryptfs_superblock_to_private( 2410 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2411 size_t written; 2412 struct ecryptfs_key_record *key_rec; 2413 struct ecryptfs_key_sig *key_sig; 2414 int rc = 0; 2415 2416 (*len) = 0; 2417 mutex_lock(&crypt_stat->keysig_list_mutex); 2418 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2419 if (!key_rec) { 2420 rc = -ENOMEM; 2421 goto out; 2422 } 2423 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2424 crypt_stat_list) { 2425 memset(key_rec, 0, sizeof(*key_rec)); 2426 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2427 &auth_tok, 2428 mount_crypt_stat, 2429 key_sig->keysig); 2430 if (rc) { 2431 printk(KERN_WARNING "Unable to retrieve auth tok with " 2432 "sig = [%s]\n", key_sig->keysig); 2433 rc = process_find_global_auth_tok_for_sig_err(rc); 2434 goto out_free; 2435 } 2436 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2437 rc = write_tag_3_packet((dest_base + (*len)), 2438 &max, auth_tok, 2439 crypt_stat, key_rec, 2440 &written); 2441 up_write(&(auth_tok_key->sem)); 2442 key_put(auth_tok_key); 2443 if (rc) { 2444 ecryptfs_printk(KERN_WARNING, "Error " 2445 "writing tag 3 packet\n"); 2446 goto out_free; 2447 } 2448 (*len) += written; 2449 /* Write auth tok signature packet */ 2450 rc = write_tag_11_packet((dest_base + (*len)), &max, 2451 key_rec->sig, 2452 ECRYPTFS_SIG_SIZE, &written); 2453 if (rc) { 2454 ecryptfs_printk(KERN_ERR, "Error writing " 2455 "auth tok signature packet\n"); 2456 goto out_free; 2457 } 2458 (*len) += written; 2459 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2460 rc = write_tag_1_packet(dest_base + (*len), &max, 2461 auth_tok_key, auth_tok, 2462 crypt_stat, key_rec, &written); 2463 if (rc) { 2464 ecryptfs_printk(KERN_WARNING, "Error " 2465 "writing tag 1 packet\n"); 2466 goto out_free; 2467 } 2468 (*len) += written; 2469 } else { 2470 up_write(&(auth_tok_key->sem)); 2471 key_put(auth_tok_key); 2472 ecryptfs_printk(KERN_WARNING, "Unsupported " 2473 "authentication token type\n"); 2474 rc = -EINVAL; 2475 goto out_free; 2476 } 2477 } 2478 if (likely(max > 0)) { 2479 dest_base[(*len)] = 0x00; 2480 } else { 2481 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2482 rc = -EIO; 2483 } 2484 out_free: 2485 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2486 out: 2487 if (rc) 2488 (*len) = 0; 2489 mutex_unlock(&crypt_stat->keysig_list_mutex); 2490 return rc; 2491 } 2492 2493 struct kmem_cache *ecryptfs_key_sig_cache; 2494 2495 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2496 { 2497 struct ecryptfs_key_sig *new_key_sig; 2498 2499 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2500 if (!new_key_sig) 2501 return -ENOMEM; 2502 2503 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2504 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2505 /* Caller must hold keysig_list_mutex */ 2506 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2507 2508 return 0; 2509 } 2510 2511 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2512 2513 int 2514 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2515 char *sig, u32 global_auth_tok_flags) 2516 { 2517 struct ecryptfs_global_auth_tok *new_auth_tok; 2518 2519 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2520 GFP_KERNEL); 2521 if (!new_auth_tok) 2522 return -ENOMEM; 2523 2524 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2525 new_auth_tok->flags = global_auth_tok_flags; 2526 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2527 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2528 list_add(&new_auth_tok->mount_crypt_stat_list, 2529 &mount_crypt_stat->global_auth_tok_list); 2530 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2531 return 0; 2532 } 2533 2534