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/skcipher.h> 15 #include <linux/string.h> 16 #include <linux/pagemap.h> 17 #include <linux/key.h> 18 #include <linux/random.h> 19 #include <linux/scatterlist.h> 20 #include <linux/slab.h> 21 #include "ecryptfs_kernel.h" 22 23 /* 24 * request_key returned an error instead of a valid key address; 25 * determine the type of error, make appropriate log entries, and 26 * return an error code. 27 */ 28 static int process_request_key_err(long err_code) 29 { 30 int rc = 0; 31 32 switch (err_code) { 33 case -ENOKEY: 34 ecryptfs_printk(KERN_WARNING, "No key\n"); 35 rc = -ENOENT; 36 break; 37 case -EKEYEXPIRED: 38 ecryptfs_printk(KERN_WARNING, "Key expired\n"); 39 rc = -ETIME; 40 break; 41 case -EKEYREVOKED: 42 ecryptfs_printk(KERN_WARNING, "Key revoked\n"); 43 rc = -EINVAL; 44 break; 45 default: 46 ecryptfs_printk(KERN_WARNING, "Unknown error code: " 47 "[0x%.16lx]\n", err_code); 48 rc = -EINVAL; 49 } 50 return rc; 51 } 52 53 static int process_find_global_auth_tok_for_sig_err(int err_code) 54 { 55 int rc = err_code; 56 57 switch (err_code) { 58 case -ENOENT: 59 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n"); 60 break; 61 case -EINVAL: 62 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n"); 63 break; 64 default: 65 rc = process_request_key_err(err_code); 66 break; 67 } 68 return rc; 69 } 70 71 /** 72 * ecryptfs_parse_packet_length 73 * @data: Pointer to memory containing length at offset 74 * @size: This function writes the decoded size to this memory 75 * address; zero on error 76 * @length_size: The number of bytes occupied by the encoded length 77 * 78 * Returns zero on success; non-zero on error 79 */ 80 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, 81 size_t *length_size) 82 { 83 int rc = 0; 84 85 (*length_size) = 0; 86 (*size) = 0; 87 if (data[0] < 192) { 88 /* One-byte length */ 89 (*size) = data[0]; 90 (*length_size) = 1; 91 } else if (data[0] < 224) { 92 /* Two-byte length */ 93 (*size) = (data[0] - 192) * 256; 94 (*size) += data[1] + 192; 95 (*length_size) = 2; 96 } else if (data[0] == 255) { 97 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 98 ecryptfs_printk(KERN_ERR, "Five-byte packet length not " 99 "supported\n"); 100 rc = -EINVAL; 101 goto out; 102 } else { 103 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n"); 104 rc = -EINVAL; 105 goto out; 106 } 107 out: 108 return rc; 109 } 110 111 /** 112 * ecryptfs_write_packet_length 113 * @dest: The byte array target into which to write the length. Must 114 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated. 115 * @size: The length to write. 116 * @packet_size_length: The number of bytes used to encode the packet 117 * length is written to this address. 118 * 119 * Returns zero on success; non-zero on error. 120 */ 121 int ecryptfs_write_packet_length(char *dest, size_t size, 122 size_t *packet_size_length) 123 { 124 int rc = 0; 125 126 if (size < 192) { 127 dest[0] = size; 128 (*packet_size_length) = 1; 129 } else if (size < 65536) { 130 dest[0] = (((size - 192) / 256) + 192); 131 dest[1] = ((size - 192) % 256); 132 (*packet_size_length) = 2; 133 } else { 134 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 135 rc = -EINVAL; 136 ecryptfs_printk(KERN_WARNING, 137 "Unsupported packet size: [%zd]\n", size); 138 } 139 return rc; 140 } 141 142 static int 143 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key, 144 char **packet, size_t *packet_len) 145 { 146 size_t i = 0; 147 size_t data_len; 148 size_t packet_size_len; 149 char *message; 150 int rc; 151 152 /* 153 * ***** TAG 64 Packet Format ***** 154 * | Content Type | 1 byte | 155 * | Key Identifier Size | 1 or 2 bytes | 156 * | Key Identifier | arbitrary | 157 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 158 * | Encrypted File Encryption Key | arbitrary | 159 */ 160 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX 161 + session_key->encrypted_key_size); 162 *packet = kmalloc(data_len, GFP_KERNEL); 163 message = *packet; 164 if (!message) { 165 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 166 rc = -ENOMEM; 167 goto out; 168 } 169 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE; 170 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 171 &packet_size_len); 172 if (rc) { 173 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 174 "header; cannot generate packet length\n"); 175 goto out; 176 } 177 i += packet_size_len; 178 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 179 i += ECRYPTFS_SIG_SIZE_HEX; 180 rc = ecryptfs_write_packet_length(&message[i], 181 session_key->encrypted_key_size, 182 &packet_size_len); 183 if (rc) { 184 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 185 "header; cannot generate packet length\n"); 186 goto out; 187 } 188 i += packet_size_len; 189 memcpy(&message[i], session_key->encrypted_key, 190 session_key->encrypted_key_size); 191 i += session_key->encrypted_key_size; 192 *packet_len = i; 193 out: 194 return rc; 195 } 196 197 static int 198 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code, 199 struct ecryptfs_message *msg) 200 { 201 size_t i = 0; 202 char *data; 203 size_t data_len; 204 size_t m_size; 205 size_t message_len; 206 u16 checksum = 0; 207 u16 expected_checksum = 0; 208 int rc; 209 210 /* 211 * ***** TAG 65 Packet Format ***** 212 * | Content Type | 1 byte | 213 * | Status Indicator | 1 byte | 214 * | File Encryption Key Size | 1 or 2 bytes | 215 * | File Encryption Key | arbitrary | 216 */ 217 message_len = msg->data_len; 218 data = msg->data; 219 if (message_len < 4) { 220 rc = -EIO; 221 goto out; 222 } 223 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) { 224 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n"); 225 rc = -EIO; 226 goto out; 227 } 228 if (data[i++]) { 229 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value " 230 "[%d]\n", data[i-1]); 231 rc = -EIO; 232 goto out; 233 } 234 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len); 235 if (rc) { 236 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 237 "rc = [%d]\n", rc); 238 goto out; 239 } 240 i += data_len; 241 if (message_len < (i + m_size)) { 242 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd " 243 "is shorter than expected\n"); 244 rc = -EIO; 245 goto out; 246 } 247 if (m_size < 3) { 248 ecryptfs_printk(KERN_ERR, 249 "The decrypted key is not long enough to " 250 "include a cipher code and checksum\n"); 251 rc = -EIO; 252 goto out; 253 } 254 *cipher_code = data[i++]; 255 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */ 256 session_key->decrypted_key_size = m_size - 3; 257 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) { 258 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than " 259 "the maximum key size [%d]\n", 260 session_key->decrypted_key_size, 261 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 262 rc = -EIO; 263 goto out; 264 } 265 memcpy(session_key->decrypted_key, &data[i], 266 session_key->decrypted_key_size); 267 i += session_key->decrypted_key_size; 268 expected_checksum += (unsigned char)(data[i++]) << 8; 269 expected_checksum += (unsigned char)(data[i++]); 270 for (i = 0; i < session_key->decrypted_key_size; i++) 271 checksum += session_key->decrypted_key[i]; 272 if (expected_checksum != checksum) { 273 ecryptfs_printk(KERN_ERR, "Invalid checksum for file " 274 "encryption key; expected [%x]; calculated " 275 "[%x]\n", expected_checksum, checksum); 276 rc = -EIO; 277 } 278 out: 279 return rc; 280 } 281 282 283 static int 284 write_tag_66_packet(char *signature, u8 cipher_code, 285 struct ecryptfs_crypt_stat *crypt_stat, char **packet, 286 size_t *packet_len) 287 { 288 size_t i = 0; 289 size_t j; 290 size_t data_len; 291 size_t checksum = 0; 292 size_t packet_size_len; 293 char *message; 294 int rc; 295 296 /* 297 * ***** TAG 66 Packet Format ***** 298 * | Content Type | 1 byte | 299 * | Key Identifier Size | 1 or 2 bytes | 300 * | Key Identifier | arbitrary | 301 * | File Encryption Key Size | 1 or 2 bytes | 302 * | Cipher Code | 1 byte | 303 * | File Encryption Key | arbitrary | 304 * | Checksum | 2 bytes | 305 */ 306 data_len = (8 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); 307 *packet = kmalloc(data_len, GFP_KERNEL); 308 message = *packet; 309 if (!message) { 310 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 311 rc = -ENOMEM; 312 goto out; 313 } 314 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; 315 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 316 &packet_size_len); 317 if (rc) { 318 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 319 "header; cannot generate packet length\n"); 320 goto out; 321 } 322 i += packet_size_len; 323 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 324 i += ECRYPTFS_SIG_SIZE_HEX; 325 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */ 326 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, 327 &packet_size_len); 328 if (rc) { 329 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 330 "header; cannot generate packet length\n"); 331 goto out; 332 } 333 i += packet_size_len; 334 message[i++] = cipher_code; 335 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); 336 i += crypt_stat->key_size; 337 for (j = 0; j < crypt_stat->key_size; j++) 338 checksum += crypt_stat->key[j]; 339 message[i++] = (checksum / 256) % 256; 340 message[i++] = (checksum % 256); 341 *packet_len = i; 342 out: 343 return rc; 344 } 345 346 static int 347 parse_tag_67_packet(struct ecryptfs_key_record *key_rec, 348 struct ecryptfs_message *msg) 349 { 350 size_t i = 0; 351 char *data; 352 size_t data_len; 353 size_t message_len; 354 int rc; 355 356 /* 357 * ***** TAG 67 Packet Format ***** 358 * | Content Type | 1 byte | 359 * | Status Indicator | 1 byte | 360 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 361 * | Encrypted File Encryption Key | arbitrary | 362 */ 363 message_len = msg->data_len; 364 data = msg->data; 365 /* verify that everything through the encrypted FEK size is present */ 366 if (message_len < 4) { 367 rc = -EIO; 368 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " 369 "message length is [%d]\n", __func__, message_len, 4); 370 goto out; 371 } 372 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { 373 rc = -EIO; 374 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", 375 __func__); 376 goto out; 377 } 378 if (data[i++]) { 379 rc = -EIO; 380 printk(KERN_ERR "%s: Status indicator has non zero " 381 "value [%d]\n", __func__, data[i-1]); 382 383 goto out; 384 } 385 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, 386 &data_len); 387 if (rc) { 388 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 389 "rc = [%d]\n", rc); 390 goto out; 391 } 392 i += data_len; 393 if (message_len < (i + key_rec->enc_key_size)) { 394 rc = -EIO; 395 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", 396 __func__, message_len, (i + key_rec->enc_key_size)); 397 goto out; 398 } 399 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 400 rc = -EIO; 401 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " 402 "the maximum key size [%d]\n", __func__, 403 key_rec->enc_key_size, 404 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 405 goto out; 406 } 407 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); 408 out: 409 return rc; 410 } 411 412 /** 413 * ecryptfs_verify_version 414 * @version: The version number to confirm 415 * 416 * Returns zero on good version; non-zero otherwise 417 */ 418 static int ecryptfs_verify_version(u16 version) 419 { 420 int rc = 0; 421 unsigned char major; 422 unsigned char minor; 423 424 major = ((version >> 8) & 0xFF); 425 minor = (version & 0xFF); 426 if (major != ECRYPTFS_VERSION_MAJOR) { 427 ecryptfs_printk(KERN_ERR, "Major version number mismatch. " 428 "Expected [%d]; got [%d]\n", 429 ECRYPTFS_VERSION_MAJOR, major); 430 rc = -EINVAL; 431 goto out; 432 } 433 if (minor != ECRYPTFS_VERSION_MINOR) { 434 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " 435 "Expected [%d]; got [%d]\n", 436 ECRYPTFS_VERSION_MINOR, minor); 437 rc = -EINVAL; 438 goto out; 439 } 440 out: 441 return rc; 442 } 443 444 /** 445 * ecryptfs_verify_auth_tok_from_key 446 * @auth_tok_key: key containing the authentication token 447 * @auth_tok: authentication token 448 * 449 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or 450 * -EKEYREVOKED if the key was revoked before we acquired its semaphore. 451 */ 452 static int 453 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, 454 struct ecryptfs_auth_tok **auth_tok) 455 { 456 int rc = 0; 457 458 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); 459 if (IS_ERR(*auth_tok)) { 460 rc = PTR_ERR(*auth_tok); 461 *auth_tok = NULL; 462 goto out; 463 } 464 465 if (ecryptfs_verify_version((*auth_tok)->version)) { 466 printk(KERN_ERR "Data structure version mismatch. Userspace " 467 "tools must match eCryptfs kernel module with major " 468 "version [%d] and minor version [%d]\n", 469 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); 470 rc = -EINVAL; 471 goto out; 472 } 473 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD 474 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { 475 printk(KERN_ERR "Invalid auth_tok structure " 476 "returned from key query\n"); 477 rc = -EINVAL; 478 goto out; 479 } 480 out: 481 return rc; 482 } 483 484 static int 485 ecryptfs_find_global_auth_tok_for_sig( 486 struct key **auth_tok_key, 487 struct ecryptfs_auth_tok **auth_tok, 488 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) 489 { 490 struct ecryptfs_global_auth_tok *walker; 491 int rc = 0; 492 493 (*auth_tok_key) = NULL; 494 (*auth_tok) = NULL; 495 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 496 list_for_each_entry(walker, 497 &mount_crypt_stat->global_auth_tok_list, 498 mount_crypt_stat_list) { 499 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) 500 continue; 501 502 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { 503 rc = -EINVAL; 504 goto out; 505 } 506 507 rc = key_validate(walker->global_auth_tok_key); 508 if (rc) { 509 if (rc == -EKEYEXPIRED) 510 goto out; 511 goto out_invalid_auth_tok; 512 } 513 514 down_write(&(walker->global_auth_tok_key->sem)); 515 rc = ecryptfs_verify_auth_tok_from_key( 516 walker->global_auth_tok_key, auth_tok); 517 if (rc) 518 goto out_invalid_auth_tok_unlock; 519 520 (*auth_tok_key) = walker->global_auth_tok_key; 521 key_get(*auth_tok_key); 522 goto out; 523 } 524 rc = -ENOENT; 525 goto out; 526 out_invalid_auth_tok_unlock: 527 up_write(&(walker->global_auth_tok_key->sem)); 528 out_invalid_auth_tok: 529 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); 530 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; 531 key_put(walker->global_auth_tok_key); 532 walker->global_auth_tok_key = NULL; 533 out: 534 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 535 return rc; 536 } 537 538 /** 539 * ecryptfs_find_auth_tok_for_sig 540 * @auth_tok_key: key containing the authentication token 541 * @auth_tok: Set to the matching auth_tok; NULL if not found 542 * @mount_crypt_stat: inode crypt_stat crypto context 543 * @sig: Sig of auth_tok to find 544 * 545 * For now, this function simply looks at the registered auth_tok's 546 * linked off the mount_crypt_stat, so all the auth_toks that can be 547 * used must be registered at mount time. This function could 548 * potentially try a lot harder to find auth_tok's (e.g., by calling 549 * out to ecryptfsd to dynamically retrieve an auth_tok object) so 550 * that static registration of auth_tok's will no longer be necessary. 551 * 552 * Returns zero on no error; non-zero on error 553 */ 554 static int 555 ecryptfs_find_auth_tok_for_sig( 556 struct key **auth_tok_key, 557 struct ecryptfs_auth_tok **auth_tok, 558 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 559 char *sig) 560 { 561 int rc = 0; 562 563 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, 564 mount_crypt_stat, sig); 565 if (rc == -ENOENT) { 566 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the 567 * mount_crypt_stat structure, we prevent to use auth toks that 568 * are not inserted through the ecryptfs_add_global_auth_tok 569 * function. 570 */ 571 if (mount_crypt_stat->flags 572 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) 573 return -EINVAL; 574 575 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, 576 sig); 577 } 578 return rc; 579 } 580 581 /* 582 * write_tag_70_packet can gobble a lot of stack space. We stuff most 583 * of the function's parameters in a kmalloc'd struct to help reduce 584 * eCryptfs' overall stack usage. 585 */ 586 struct ecryptfs_write_tag_70_packet_silly_stack { 587 u8 cipher_code; 588 size_t max_packet_size; 589 size_t packet_size_len; 590 size_t block_aligned_filename_size; 591 size_t block_size; 592 size_t i; 593 size_t j; 594 size_t num_rand_bytes; 595 struct mutex *tfm_mutex; 596 char *block_aligned_filename; 597 struct ecryptfs_auth_tok *auth_tok; 598 struct scatterlist src_sg[2]; 599 struct scatterlist dst_sg[2]; 600 struct crypto_skcipher *skcipher_tfm; 601 struct skcipher_request *skcipher_req; 602 char iv[ECRYPTFS_MAX_IV_BYTES]; 603 char hash[MD5_DIGEST_SIZE]; 604 }; 605 606 /* 607 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK 608 * @filename: NULL-terminated filename string 609 * 610 * This is the simplest mechanism for achieving filename encryption in 611 * eCryptfs. It encrypts the given filename with the mount-wide 612 * filename encryption key (FNEK) and stores it in a packet to @dest, 613 * which the callee will encode and write directly into the dentry 614 * name. 615 */ 616 int 617 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, 618 size_t *packet_size, 619 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 620 char *filename, size_t filename_size) 621 { 622 struct ecryptfs_write_tag_70_packet_silly_stack *s; 623 struct key *auth_tok_key = NULL; 624 int rc = 0; 625 626 s = kzalloc_obj(*s); 627 if (!s) 628 return -ENOMEM; 629 630 (*packet_size) = 0; 631 rc = ecryptfs_find_auth_tok_for_sig( 632 &auth_tok_key, 633 &s->auth_tok, mount_crypt_stat, 634 mount_crypt_stat->global_default_fnek_sig); 635 if (rc) { 636 printk(KERN_ERR "%s: Error attempting to find auth tok for " 637 "fnek sig [%s]; rc = [%d]\n", __func__, 638 mount_crypt_stat->global_default_fnek_sig, rc); 639 goto out; 640 } 641 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 642 &s->skcipher_tfm, 643 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 644 if (unlikely(rc)) { 645 printk(KERN_ERR "Internal error whilst attempting to get " 646 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 647 mount_crypt_stat->global_default_fn_cipher_name, rc); 648 goto out; 649 } 650 mutex_lock(s->tfm_mutex); 651 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm); 652 /* Plus one for the \0 separator between the random prefix 653 * and the plaintext filename */ 654 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 655 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 656 if ((s->block_aligned_filename_size % s->block_size) != 0) { 657 s->num_rand_bytes += (s->block_size 658 - (s->block_aligned_filename_size 659 % s->block_size)); 660 s->block_aligned_filename_size = (s->num_rand_bytes 661 + filename_size); 662 } 663 /* Octet 0: Tag 70 identifier 664 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 665 * and block-aligned encrypted filename size) 666 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 667 * Octet N2-N3: Cipher identifier (1 octet) 668 * Octets N3-N4: Block-aligned encrypted filename 669 * - Consists of a minimum number of random characters, a \0 670 * separator, and then the filename */ 671 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 672 + s->block_aligned_filename_size); 673 if (!dest) { 674 (*packet_size) = s->max_packet_size; 675 goto out_unlock; 676 } 677 if (s->max_packet_size > (*remaining_bytes)) { 678 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 679 "[%zd] available\n", __func__, s->max_packet_size, 680 (*remaining_bytes)); 681 rc = -EINVAL; 682 goto out_unlock; 683 } 684 685 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 686 if (!s->skcipher_req) { 687 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 688 "skcipher_request_alloc for %s\n", __func__, 689 crypto_skcipher_driver_name(s->skcipher_tfm)); 690 rc = -ENOMEM; 691 goto out_unlock; 692 } 693 694 skcipher_request_set_callback(s->skcipher_req, 695 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 696 697 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 698 GFP_KERNEL); 699 if (!s->block_aligned_filename) { 700 rc = -ENOMEM; 701 goto out_unlock; 702 } 703 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 704 rc = ecryptfs_write_packet_length(&dest[s->i], 705 (ECRYPTFS_SIG_SIZE 706 + 1 /* Cipher code */ 707 + s->block_aligned_filename_size), 708 &s->packet_size_len); 709 if (rc) { 710 printk(KERN_ERR "%s: Error generating tag 70 packet " 711 "header; cannot generate packet length; rc = [%d]\n", 712 __func__, rc); 713 goto out_free_unlock; 714 } 715 s->i += s->packet_size_len; 716 ecryptfs_from_hex(&dest[s->i], 717 mount_crypt_stat->global_default_fnek_sig, 718 ECRYPTFS_SIG_SIZE); 719 s->i += ECRYPTFS_SIG_SIZE; 720 s->cipher_code = ecryptfs_code_for_cipher_string( 721 mount_crypt_stat->global_default_fn_cipher_name, 722 mount_crypt_stat->global_default_fn_cipher_key_bytes); 723 if (s->cipher_code == 0) { 724 printk(KERN_WARNING "%s: Unable to generate code for " 725 "cipher [%s] with key bytes [%zd]\n", __func__, 726 mount_crypt_stat->global_default_fn_cipher_name, 727 mount_crypt_stat->global_default_fn_cipher_key_bytes); 728 rc = -EINVAL; 729 goto out_free_unlock; 730 } 731 dest[s->i++] = s->cipher_code; 732 /* TODO: Support other key modules than passphrase for 733 * filename encryption */ 734 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 735 rc = -EOPNOTSUPP; 736 printk(KERN_INFO "%s: Filename encryption only supports " 737 "password tokens\n", __func__); 738 goto out_free_unlock; 739 } 740 741 md5(s->auth_tok->token.password.session_key_encryption_key, 742 s->auth_tok->token.password.session_key_encryption_key_bytes, 743 s->hash); 744 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 745 s->block_aligned_filename[s->j] = 746 s->hash[s->j % MD5_DIGEST_SIZE]; 747 if ((s->j % MD5_DIGEST_SIZE) == (MD5_DIGEST_SIZE - 1)) 748 md5(s->hash, MD5_DIGEST_SIZE, s->hash); 749 if (s->block_aligned_filename[s->j] == '\0') 750 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 751 } 752 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 753 filename_size); 754 rc = virt_to_scatterlist(s->block_aligned_filename, 755 s->block_aligned_filename_size, s->src_sg, 2); 756 if (rc < 1) { 757 printk(KERN_ERR "%s: Internal error whilst attempting to " 758 "convert filename memory to scatterlist; rc = [%d]. " 759 "block_aligned_filename_size = [%zd]\n", __func__, rc, 760 s->block_aligned_filename_size); 761 goto out_free_unlock; 762 } 763 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 764 s->dst_sg, 2); 765 if (rc < 1) { 766 printk(KERN_ERR "%s: Internal error whilst attempting to " 767 "convert encrypted filename memory to scatterlist; " 768 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 769 __func__, rc, s->block_aligned_filename_size); 770 goto out_free_unlock; 771 } 772 /* The characters in the first block effectively do the job 773 * of the IV here, so we just use 0's for the IV. Note the 774 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 775 * >= ECRYPTFS_MAX_IV_BYTES. */ 776 rc = crypto_skcipher_setkey( 777 s->skcipher_tfm, 778 s->auth_tok->token.password.session_key_encryption_key, 779 mount_crypt_stat->global_default_fn_cipher_key_bytes); 780 if (rc < 0) { 781 printk(KERN_ERR "%s: Error setting key for crypto context; " 782 "rc = [%d]. s->auth_tok->token.password.session_key_" 783 "encryption_key = [0x%p]; mount_crypt_stat->" 784 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 785 rc, 786 s->auth_tok->token.password.session_key_encryption_key, 787 mount_crypt_stat->global_default_fn_cipher_key_bytes); 788 goto out_free_unlock; 789 } 790 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 791 s->block_aligned_filename_size, s->iv); 792 rc = crypto_skcipher_encrypt(s->skcipher_req); 793 if (rc) { 794 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 795 "rc = [%d]\n", __func__, rc); 796 goto out_free_unlock; 797 } 798 s->i += s->block_aligned_filename_size; 799 (*packet_size) = s->i; 800 (*remaining_bytes) -= (*packet_size); 801 out_free_unlock: 802 kfree_sensitive(s->block_aligned_filename); 803 out_unlock: 804 mutex_unlock(s->tfm_mutex); 805 out: 806 if (auth_tok_key) { 807 up_write(&(auth_tok_key->sem)); 808 key_put(auth_tok_key); 809 } 810 skcipher_request_free(s->skcipher_req); 811 kfree(s); 812 return rc; 813 } 814 815 struct ecryptfs_parse_tag_70_packet_silly_stack { 816 u8 cipher_code; 817 size_t max_packet_size; 818 size_t packet_size_len; 819 size_t parsed_tag_70_packet_size; 820 size_t block_aligned_filename_size; 821 size_t block_size; 822 size_t i; 823 struct mutex *tfm_mutex; 824 char *decrypted_filename; 825 struct ecryptfs_auth_tok *auth_tok; 826 struct scatterlist src_sg[2]; 827 struct scatterlist dst_sg[2]; 828 struct crypto_skcipher *skcipher_tfm; 829 struct skcipher_request *skcipher_req; 830 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 831 char iv[ECRYPTFS_MAX_IV_BYTES]; 832 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; 833 }; 834 835 /** 836 * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 837 * @filename: This function kmalloc's the memory for the filename 838 * @filename_size: This function sets this to the amount of memory 839 * kmalloc'd for the filename 840 * @packet_size: This function sets this to the number of octets 841 * in the packet parsed 842 * @mount_crypt_stat: The mount-wide cryptographic context 843 * @data: The memory location containing the start of the tag 70 844 * packet 845 * @max_packet_size: The maximum legal size of the packet to be parsed 846 * from @data 847 * 848 * Returns zero on success; non-zero otherwise 849 */ 850 int 851 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 852 size_t *packet_size, 853 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 854 char *data, size_t max_packet_size) 855 { 856 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 857 struct key *auth_tok_key = NULL; 858 int rc = 0; 859 860 (*packet_size) = 0; 861 (*filename_size) = 0; 862 (*filename) = NULL; 863 s = kzalloc_obj(*s); 864 if (!s) 865 return -ENOMEM; 866 867 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 868 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 869 "at least [%d]\n", __func__, max_packet_size, 870 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 871 rc = -EINVAL; 872 goto out; 873 } 874 /* Octet 0: Tag 70 identifier 875 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 876 * and block-aligned encrypted filename size) 877 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 878 * Octet N2-N3: Cipher identifier (1 octet) 879 * Octets N3-N4: Block-aligned encrypted filename 880 * - Consists of a minimum number of random numbers, a \0 881 * separator, and then the filename */ 882 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 883 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 884 "tag [0x%.2x]\n", __func__, 885 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 886 rc = -EINVAL; 887 goto out; 888 } 889 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 890 &s->parsed_tag_70_packet_size, 891 &s->packet_size_len); 892 if (rc) { 893 printk(KERN_WARNING "%s: Error parsing packet length; " 894 "rc = [%d]\n", __func__, rc); 895 goto out; 896 } 897 if (s->parsed_tag_70_packet_size < (ECRYPTFS_SIG_SIZE + 2)) { 898 ecryptfs_printk(KERN_WARNING, "Invalid packet size [%zd]\n", 899 s->parsed_tag_70_packet_size); 900 rc = -EINVAL; 901 goto out; 902 } 903 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 904 - ECRYPTFS_SIG_SIZE - 1); 905 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 906 > max_packet_size) { 907 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 908 "size is [%zd]\n", __func__, max_packet_size, 909 (1 + s->packet_size_len + 1 910 + s->block_aligned_filename_size)); 911 rc = -EINVAL; 912 goto out; 913 } 914 (*packet_size) += s->packet_size_len; 915 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 916 ECRYPTFS_SIG_SIZE); 917 (*packet_size) += ECRYPTFS_SIG_SIZE; 918 s->cipher_code = data[(*packet_size)++]; 919 rc = ecryptfs_cipher_code_to_string(s->cipher_string, 920 sizeof(s->cipher_string), 921 s->cipher_code); 922 if (rc) { 923 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 924 __func__, s->cipher_code); 925 goto out; 926 } 927 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 928 &s->auth_tok, mount_crypt_stat, 929 s->fnek_sig_hex); 930 if (rc) { 931 printk(KERN_ERR "%s: Error attempting to find auth tok for " 932 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 933 rc); 934 goto out; 935 } 936 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm, 937 &s->tfm_mutex, 938 s->cipher_string); 939 if (unlikely(rc)) { 940 printk(KERN_ERR "Internal error whilst attempting to get " 941 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 942 s->cipher_string, rc); 943 goto out; 944 } 945 mutex_lock(s->tfm_mutex); 946 rc = virt_to_scatterlist(&data[(*packet_size)], 947 s->block_aligned_filename_size, s->src_sg, 2); 948 if (rc < 1) { 949 printk(KERN_ERR "%s: Internal error whilst attempting to " 950 "convert encrypted filename memory to scatterlist; " 951 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 952 __func__, rc, s->block_aligned_filename_size); 953 goto out_unlock; 954 } 955 (*packet_size) += s->block_aligned_filename_size; 956 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 957 GFP_KERNEL); 958 if (!s->decrypted_filename) { 959 rc = -ENOMEM; 960 goto out_unlock; 961 } 962 rc = virt_to_scatterlist(s->decrypted_filename, 963 s->block_aligned_filename_size, s->dst_sg, 2); 964 if (rc < 1) { 965 printk(KERN_ERR "%s: Internal error whilst attempting to " 966 "convert decrypted filename memory to scatterlist; " 967 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 968 __func__, rc, s->block_aligned_filename_size); 969 goto out_free_unlock; 970 } 971 972 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 973 if (!s->skcipher_req) { 974 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 975 "skcipher_request_alloc for %s\n", __func__, 976 crypto_skcipher_driver_name(s->skcipher_tfm)); 977 rc = -ENOMEM; 978 goto out_free_unlock; 979 } 980 981 skcipher_request_set_callback(s->skcipher_req, 982 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 983 984 /* The characters in the first block effectively do the job of 985 * the IV here, so we just use 0's for the IV. Note the 986 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 987 * >= ECRYPTFS_MAX_IV_BYTES. */ 988 /* TODO: Support other key modules than passphrase for 989 * filename encryption */ 990 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 991 rc = -EOPNOTSUPP; 992 printk(KERN_INFO "%s: Filename encryption only supports " 993 "password tokens\n", __func__); 994 goto out_free_unlock; 995 } 996 rc = crypto_skcipher_setkey( 997 s->skcipher_tfm, 998 s->auth_tok->token.password.session_key_encryption_key, 999 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1000 if (rc < 0) { 1001 printk(KERN_ERR "%s: Error setting key for crypto context; " 1002 "rc = [%d]. s->auth_tok->token.password.session_key_" 1003 "encryption_key = [0x%p]; mount_crypt_stat->" 1004 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1005 rc, 1006 s->auth_tok->token.password.session_key_encryption_key, 1007 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1008 goto out_free_unlock; 1009 } 1010 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 1011 s->block_aligned_filename_size, s->iv); 1012 rc = crypto_skcipher_decrypt(s->skcipher_req); 1013 if (rc) { 1014 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1015 "rc = [%d]\n", __func__, rc); 1016 goto out_free_unlock; 1017 } 1018 1019 while (s->i < s->block_aligned_filename_size && 1020 s->decrypted_filename[s->i] != '\0') 1021 s->i++; 1022 if (s->i == s->block_aligned_filename_size) { 1023 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1024 "find valid separator between random characters and " 1025 "the filename\n", __func__); 1026 rc = -EINVAL; 1027 goto out_free_unlock; 1028 } 1029 s->i++; 1030 (*filename_size) = (s->block_aligned_filename_size - s->i); 1031 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1032 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1033 "invalid\n", __func__, (*filename_size)); 1034 rc = -EINVAL; 1035 goto out_free_unlock; 1036 } 1037 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1038 if (!(*filename)) { 1039 rc = -ENOMEM; 1040 goto out_free_unlock; 1041 } 1042 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1043 (*filename)[(*filename_size)] = '\0'; 1044 out_free_unlock: 1045 kfree(s->decrypted_filename); 1046 out_unlock: 1047 mutex_unlock(s->tfm_mutex); 1048 out: 1049 if (rc) { 1050 (*packet_size) = 0; 1051 (*filename_size) = 0; 1052 (*filename) = NULL; 1053 } 1054 if (auth_tok_key) { 1055 up_write(&(auth_tok_key->sem)); 1056 key_put(auth_tok_key); 1057 } 1058 skcipher_request_free(s->skcipher_req); 1059 kfree(s); 1060 return rc; 1061 } 1062 1063 static int 1064 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1065 { 1066 int rc = 0; 1067 1068 (*sig) = NULL; 1069 switch (auth_tok->token_type) { 1070 case ECRYPTFS_PASSWORD: 1071 (*sig) = auth_tok->token.password.signature; 1072 break; 1073 case ECRYPTFS_PRIVATE_KEY: 1074 (*sig) = auth_tok->token.private_key.signature; 1075 break; 1076 default: 1077 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1078 auth_tok->token_type); 1079 rc = -EINVAL; 1080 } 1081 return rc; 1082 } 1083 1084 /** 1085 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1086 * @auth_tok: The key authentication token used to decrypt the session key 1087 * @crypt_stat: The cryptographic context 1088 * 1089 * Returns zero on success; non-zero error otherwise. 1090 */ 1091 static int 1092 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1093 struct ecryptfs_crypt_stat *crypt_stat) 1094 { 1095 u8 cipher_code = 0; 1096 struct ecryptfs_msg_ctx *msg_ctx; 1097 struct ecryptfs_message *msg = NULL; 1098 char *auth_tok_sig; 1099 char *payload = NULL; 1100 size_t payload_len = 0; 1101 int rc; 1102 1103 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1104 if (rc) { 1105 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1106 auth_tok->token_type); 1107 goto out; 1108 } 1109 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1110 &payload, &payload_len); 1111 if (rc) { 1112 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1113 goto out; 1114 } 1115 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1116 if (rc) { 1117 ecryptfs_printk(KERN_ERR, "Error sending message to " 1118 "ecryptfsd: %d\n", rc); 1119 goto out; 1120 } 1121 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1122 if (rc) { 1123 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1124 "from the user space daemon\n"); 1125 rc = -EIO; 1126 goto out; 1127 } 1128 rc = parse_tag_65_packet(&(auth_tok->session_key), 1129 &cipher_code, msg); 1130 if (rc) { 1131 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1132 rc); 1133 goto out; 1134 } 1135 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1136 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1137 auth_tok->session_key.decrypted_key_size); 1138 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1139 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1140 sizeof(crypt_stat->cipher), 1141 cipher_code); 1142 if (rc) { 1143 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1144 cipher_code); 1145 goto out; 1146 } 1147 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1148 if (ecryptfs_verbosity > 0) { 1149 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1150 ecryptfs_dump_hex(crypt_stat->key, 1151 crypt_stat->key_size); 1152 } 1153 out: 1154 kfree(msg); 1155 kfree(payload); 1156 return rc; 1157 } 1158 1159 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1160 { 1161 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1162 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1163 1164 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1165 auth_tok_list_head, list) { 1166 list_del(&auth_tok_list_item->list); 1167 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1168 auth_tok_list_item); 1169 } 1170 } 1171 1172 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1173 1174 /** 1175 * parse_tag_1_packet 1176 * @crypt_stat: The cryptographic context to modify based on packet contents 1177 * @data: The raw bytes of the packet. 1178 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1179 * a new authentication token will be placed at the 1180 * end of this list for this packet. 1181 * @new_auth_tok: Pointer to a pointer to memory that this function 1182 * allocates; sets the memory address of the pointer to 1183 * NULL on error. This object is added to the 1184 * auth_tok_list. 1185 * @packet_size: This function writes the size of the parsed packet 1186 * into this memory location; zero on error. 1187 * @max_packet_size: The maximum allowable packet size 1188 * 1189 * Returns zero on success; non-zero on error. 1190 */ 1191 static int 1192 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1193 unsigned char *data, struct list_head *auth_tok_list, 1194 struct ecryptfs_auth_tok **new_auth_tok, 1195 size_t *packet_size, size_t max_packet_size) 1196 { 1197 size_t body_size; 1198 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1199 size_t length_size; 1200 int rc = 0; 1201 1202 (*packet_size) = 0; 1203 (*new_auth_tok) = NULL; 1204 /** 1205 * This format is inspired by OpenPGP; see RFC 2440 1206 * packet tag 1 1207 * 1208 * Tag 1 identifier (1 byte) 1209 * Max Tag 1 packet size (max 3 bytes) 1210 * Version (1 byte) 1211 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1212 * Cipher identifier (1 byte) 1213 * Encrypted key size (arbitrary) 1214 * 1215 * 12 bytes minimum packet size 1216 */ 1217 if (unlikely(max_packet_size < 12)) { 1218 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1219 rc = -EINVAL; 1220 goto out; 1221 } 1222 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1223 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1224 ECRYPTFS_TAG_1_PACKET_TYPE); 1225 rc = -EINVAL; 1226 goto out; 1227 } 1228 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1229 * at end of function upon failure */ 1230 auth_tok_list_item = 1231 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1232 GFP_KERNEL); 1233 if (!auth_tok_list_item) { 1234 printk(KERN_ERR "Unable to allocate memory\n"); 1235 rc = -ENOMEM; 1236 goto out; 1237 } 1238 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1239 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1240 &length_size); 1241 if (rc) { 1242 printk(KERN_WARNING "Error parsing packet length; " 1243 "rc = [%d]\n", rc); 1244 goto out_free; 1245 } 1246 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1247 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1248 rc = -EINVAL; 1249 goto out_free; 1250 } 1251 (*packet_size) += length_size; 1252 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1253 printk(KERN_WARNING "Packet size exceeds max\n"); 1254 rc = -EINVAL; 1255 goto out_free; 1256 } 1257 if (unlikely(data[(*packet_size)++] != 0x03)) { 1258 printk(KERN_WARNING "Unknown version number [%d]\n", 1259 data[(*packet_size) - 1]); 1260 rc = -EINVAL; 1261 goto out_free; 1262 } 1263 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1264 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1265 *packet_size += ECRYPTFS_SIG_SIZE; 1266 /* This byte is skipped because the kernel does not need to 1267 * know which public key encryption algorithm was used */ 1268 (*packet_size)++; 1269 (*new_auth_tok)->session_key.encrypted_key_size = 1270 body_size - (ECRYPTFS_SIG_SIZE + 2); 1271 if ((*new_auth_tok)->session_key.encrypted_key_size 1272 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1273 printk(KERN_WARNING "Tag 1 packet contains key larger " 1274 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1275 rc = -EINVAL; 1276 goto out_free; 1277 } 1278 memcpy((*new_auth_tok)->session_key.encrypted_key, 1279 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1280 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1281 (*new_auth_tok)->session_key.flags &= 1282 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1283 (*new_auth_tok)->session_key.flags |= 1284 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1285 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1286 (*new_auth_tok)->flags = 0; 1287 (*new_auth_tok)->session_key.flags &= 1288 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1289 (*new_auth_tok)->session_key.flags &= 1290 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1291 list_add(&auth_tok_list_item->list, auth_tok_list); 1292 goto out; 1293 out_free: 1294 (*new_auth_tok) = NULL; 1295 memset(auth_tok_list_item, 0, 1296 sizeof(struct ecryptfs_auth_tok_list_item)); 1297 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1298 auth_tok_list_item); 1299 out: 1300 if (rc) 1301 (*packet_size) = 0; 1302 return rc; 1303 } 1304 1305 /** 1306 * parse_tag_3_packet 1307 * @crypt_stat: The cryptographic context to modify based on packet 1308 * contents. 1309 * @data: The raw bytes of the packet. 1310 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1311 * a new authentication token will be placed at the end 1312 * of this list for this packet. 1313 * @new_auth_tok: Pointer to a pointer to memory that this function 1314 * allocates; sets the memory address of the pointer to 1315 * NULL on error. This object is added to the 1316 * auth_tok_list. 1317 * @packet_size: This function writes the size of the parsed packet 1318 * into this memory location; zero on error. 1319 * @max_packet_size: maximum number of bytes to parse 1320 * 1321 * Returns zero on success; non-zero on error. 1322 */ 1323 static int 1324 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1325 unsigned char *data, struct list_head *auth_tok_list, 1326 struct ecryptfs_auth_tok **new_auth_tok, 1327 size_t *packet_size, size_t max_packet_size) 1328 { 1329 size_t body_size; 1330 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1331 size_t length_size; 1332 int rc = 0; 1333 1334 (*packet_size) = 0; 1335 (*new_auth_tok) = NULL; 1336 /** 1337 *This format is inspired by OpenPGP; see RFC 2440 1338 * packet tag 3 1339 * 1340 * Tag 3 identifier (1 byte) 1341 * Max Tag 3 packet size (max 3 bytes) 1342 * Version (1 byte) 1343 * Cipher code (1 byte) 1344 * S2K specifier (1 byte) 1345 * Hash identifier (1 byte) 1346 * Salt (ECRYPTFS_SALT_SIZE) 1347 * Hash iterations (1 byte) 1348 * Encrypted key (arbitrary) 1349 * 1350 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1351 */ 1352 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1353 printk(KERN_ERR "Max packet size too large\n"); 1354 rc = -EINVAL; 1355 goto out; 1356 } 1357 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1358 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1359 ECRYPTFS_TAG_3_PACKET_TYPE); 1360 rc = -EINVAL; 1361 goto out; 1362 } 1363 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1364 * at end of function upon failure */ 1365 auth_tok_list_item = 1366 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1367 if (!auth_tok_list_item) { 1368 printk(KERN_ERR "Unable to allocate memory\n"); 1369 rc = -ENOMEM; 1370 goto out; 1371 } 1372 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1373 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1374 &length_size); 1375 if (rc) { 1376 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1377 rc); 1378 goto out_free; 1379 } 1380 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1381 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1382 rc = -EINVAL; 1383 goto out_free; 1384 } 1385 (*packet_size) += length_size; 1386 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1387 printk(KERN_ERR "Packet size exceeds max\n"); 1388 rc = -EINVAL; 1389 goto out_free; 1390 } 1391 (*new_auth_tok)->session_key.encrypted_key_size = 1392 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1393 /* 1394 * Although encrypted_key_size is copied into the 1395 * encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES] buffer here, 1396 * it later bounds operations on a smaller buffer: 1397 * decrypt_passphrase_encrypted_session_key() sets decrypted_key_size = 1398 * encrypted_key_size and decrypts into 1399 * decrypted_key[ECRYPTFS_MAX_KEY_BYTES], then memcpy's into 1400 * crypt_stat->key[ECRYPTFS_MAX_KEY_BYTES]. Limit to 1401 * ECRYPTFS_MAX_KEY_BYTES to protect those smaller buffers. 1402 */ 1403 if ((*new_auth_tok)->session_key.encrypted_key_size 1404 > ECRYPTFS_MAX_KEY_BYTES) { 1405 printk(KERN_WARNING "Tag 3 packet contains key larger " 1406 "than ECRYPTFS_MAX_KEY_BYTES\n"); 1407 rc = -EINVAL; 1408 goto out_free; 1409 } 1410 if (unlikely(data[(*packet_size)++] != 0x04)) { 1411 printk(KERN_WARNING "Unknown version number [%d]\n", 1412 data[(*packet_size) - 1]); 1413 rc = -EINVAL; 1414 goto out_free; 1415 } 1416 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1417 sizeof(crypt_stat->cipher), 1418 (u16)data[(*packet_size)]); 1419 if (rc) 1420 goto out_free; 1421 /* A little extra work to differentiate among the AES key 1422 * sizes; see RFC2440 */ 1423 switch(data[(*packet_size)++]) { 1424 case RFC2440_CIPHER_AES_192: 1425 crypt_stat->key_size = 24; 1426 break; 1427 default: 1428 crypt_stat->key_size = 1429 (*new_auth_tok)->session_key.encrypted_key_size; 1430 } 1431 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1432 if (rc) 1433 goto out_free; 1434 if (unlikely(data[(*packet_size)++] != 0x03)) { 1435 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1436 rc = -ENOSYS; 1437 goto out_free; 1438 } 1439 /* TODO: finish the hash mapping */ 1440 switch (data[(*packet_size)++]) { 1441 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1442 /* Choose MD5 */ 1443 memcpy((*new_auth_tok)->token.password.salt, 1444 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1445 (*packet_size) += ECRYPTFS_SALT_SIZE; 1446 /* This conversion was taken straight from RFC2440 */ 1447 (*new_auth_tok)->token.password.hash_iterations = 1448 ((u32) 16 + (data[(*packet_size)] & 15)) 1449 << ((data[(*packet_size)] >> 4) + 6); 1450 (*packet_size)++; 1451 /* Friendly reminder: 1452 * (*new_auth_tok)->session_key.encrypted_key_size = 1453 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1454 memcpy((*new_auth_tok)->session_key.encrypted_key, 1455 &data[(*packet_size)], 1456 (*new_auth_tok)->session_key.encrypted_key_size); 1457 (*packet_size) += 1458 (*new_auth_tok)->session_key.encrypted_key_size; 1459 (*new_auth_tok)->session_key.flags &= 1460 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1461 (*new_auth_tok)->session_key.flags |= 1462 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1463 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1464 break; 1465 default: 1466 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1467 "[%d]\n", data[(*packet_size) - 1]); 1468 rc = -ENOSYS; 1469 goto out_free; 1470 } 1471 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1472 /* TODO: Parametarize; we might actually want userspace to 1473 * decrypt the session key. */ 1474 (*new_auth_tok)->session_key.flags &= 1475 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1476 (*new_auth_tok)->session_key.flags &= 1477 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1478 list_add(&auth_tok_list_item->list, auth_tok_list); 1479 goto out; 1480 out_free: 1481 (*new_auth_tok) = NULL; 1482 memset(auth_tok_list_item, 0, 1483 sizeof(struct ecryptfs_auth_tok_list_item)); 1484 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1485 auth_tok_list_item); 1486 out: 1487 if (rc) 1488 (*packet_size) = 0; 1489 return rc; 1490 } 1491 1492 /** 1493 * parse_tag_11_packet 1494 * @data: The raw bytes of the packet 1495 * @contents: This function writes the data contents of the literal 1496 * packet into this memory location 1497 * @max_contents_bytes: The maximum number of bytes that this function 1498 * is allowed to write into contents 1499 * @tag_11_contents_size: This function writes the size of the parsed 1500 * contents into this memory location; zero on 1501 * error 1502 * @packet_size: This function writes the size of the parsed packet 1503 * into this memory location; zero on error 1504 * @max_packet_size: maximum number of bytes to parse 1505 * 1506 * Returns zero on success; non-zero on error. 1507 */ 1508 static int 1509 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1510 size_t max_contents_bytes, size_t *tag_11_contents_size, 1511 size_t *packet_size, size_t max_packet_size) 1512 { 1513 size_t body_size; 1514 size_t length_size; 1515 int rc = 0; 1516 1517 (*packet_size) = 0; 1518 (*tag_11_contents_size) = 0; 1519 /* This format is inspired by OpenPGP; see RFC 2440 1520 * packet tag 11 1521 * 1522 * Tag 11 identifier (1 byte) 1523 * Max Tag 11 packet size (max 3 bytes) 1524 * Binary format specifier (1 byte) 1525 * Filename length (1 byte) 1526 * Filename ("_CONSOLE") (8 bytes) 1527 * Modification date (4 bytes) 1528 * Literal data (arbitrary) 1529 * 1530 * We need at least 16 bytes of data for the packet to even be 1531 * valid. 1532 */ 1533 if (max_packet_size < 16) { 1534 printk(KERN_ERR "Maximum packet size too small\n"); 1535 rc = -EINVAL; 1536 goto out; 1537 } 1538 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1539 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1540 rc = -EINVAL; 1541 goto out; 1542 } 1543 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1544 &length_size); 1545 if (rc) { 1546 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1547 goto out; 1548 } 1549 if (body_size < 14) { 1550 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1551 rc = -EINVAL; 1552 goto out; 1553 } 1554 (*packet_size) += length_size; 1555 (*tag_11_contents_size) = (body_size - 14); 1556 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1557 printk(KERN_ERR "Packet size exceeds max\n"); 1558 rc = -EINVAL; 1559 goto out; 1560 } 1561 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1562 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1563 "expected size\n"); 1564 rc = -EINVAL; 1565 goto out; 1566 } 1567 if (data[(*packet_size)++] != 0x62) { 1568 printk(KERN_WARNING "Unrecognizable packet\n"); 1569 rc = -EINVAL; 1570 goto out; 1571 } 1572 if (data[(*packet_size)++] != 0x08) { 1573 printk(KERN_WARNING "Unrecognizable packet\n"); 1574 rc = -EINVAL; 1575 goto out; 1576 } 1577 (*packet_size) += 12; /* Ignore filename and modification date */ 1578 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1579 (*packet_size) += (*tag_11_contents_size); 1580 out: 1581 if (rc) { 1582 (*packet_size) = 0; 1583 (*tag_11_contents_size) = 0; 1584 } 1585 return rc; 1586 } 1587 1588 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1589 struct ecryptfs_auth_tok **auth_tok, 1590 char *sig) 1591 { 1592 int rc = 0; 1593 1594 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1595 if (IS_ERR(*auth_tok_key)) { 1596 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1597 if (IS_ERR(*auth_tok_key)) { 1598 printk(KERN_ERR "Could not find key with description: [%s]\n", 1599 sig); 1600 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1601 (*auth_tok_key) = NULL; 1602 goto out; 1603 } 1604 } 1605 down_write(&(*auth_tok_key)->sem); 1606 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1607 if (rc) { 1608 up_write(&(*auth_tok_key)->sem); 1609 key_put(*auth_tok_key); 1610 (*auth_tok_key) = NULL; 1611 goto out; 1612 } 1613 out: 1614 return rc; 1615 } 1616 1617 /** 1618 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1619 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1620 * @crypt_stat: The cryptographic context 1621 * 1622 * Returns zero on success; non-zero error otherwise 1623 */ 1624 static int 1625 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1626 struct ecryptfs_crypt_stat *crypt_stat) 1627 { 1628 struct scatterlist dst_sg[2]; 1629 struct scatterlist src_sg[2]; 1630 struct mutex *tfm_mutex; 1631 struct crypto_skcipher *tfm; 1632 struct skcipher_request *req = NULL; 1633 int rc = 0; 1634 1635 if (unlikely(ecryptfs_verbosity > 0)) { 1636 ecryptfs_printk( 1637 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1638 auth_tok->token.password.session_key_encryption_key_bytes); 1639 ecryptfs_dump_hex( 1640 auth_tok->token.password.session_key_encryption_key, 1641 auth_tok->token.password.session_key_encryption_key_bytes); 1642 } 1643 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 1644 crypt_stat->cipher); 1645 if (unlikely(rc)) { 1646 printk(KERN_ERR "Internal error whilst attempting to get " 1647 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1648 crypt_stat->cipher, rc); 1649 goto out; 1650 } 1651 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1652 auth_tok->session_key.encrypted_key_size, 1653 src_sg, 2); 1654 if (rc < 1 || rc > 2) { 1655 printk(KERN_ERR "Internal error whilst attempting to convert " 1656 "auth_tok->session_key.encrypted_key to scatterlist; " 1657 "expected rc = 1; got rc = [%d]. " 1658 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1659 auth_tok->session_key.encrypted_key_size); 1660 goto out; 1661 } 1662 auth_tok->session_key.decrypted_key_size = 1663 auth_tok->session_key.encrypted_key_size; 1664 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1665 auth_tok->session_key.decrypted_key_size, 1666 dst_sg, 2); 1667 if (rc < 1 || rc > 2) { 1668 printk(KERN_ERR "Internal error whilst attempting to convert " 1669 "auth_tok->session_key.decrypted_key to scatterlist; " 1670 "expected rc = 1; got rc = [%d]\n", rc); 1671 goto out; 1672 } 1673 mutex_lock(tfm_mutex); 1674 req = skcipher_request_alloc(tfm, GFP_KERNEL); 1675 if (!req) { 1676 mutex_unlock(tfm_mutex); 1677 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1678 "skcipher_request_alloc for %s\n", __func__, 1679 crypto_skcipher_driver_name(tfm)); 1680 rc = -ENOMEM; 1681 goto out; 1682 } 1683 1684 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 1685 NULL, NULL); 1686 rc = crypto_skcipher_setkey( 1687 tfm, auth_tok->token.password.session_key_encryption_key, 1688 crypt_stat->key_size); 1689 if (unlikely(rc < 0)) { 1690 mutex_unlock(tfm_mutex); 1691 printk(KERN_ERR "Error setting key for crypto context\n"); 1692 rc = -EINVAL; 1693 goto out; 1694 } 1695 skcipher_request_set_crypt(req, src_sg, dst_sg, 1696 auth_tok->session_key.encrypted_key_size, 1697 NULL); 1698 rc = crypto_skcipher_decrypt(req); 1699 mutex_unlock(tfm_mutex); 1700 if (unlikely(rc)) { 1701 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1702 goto out; 1703 } 1704 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1705 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1706 auth_tok->session_key.decrypted_key_size); 1707 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1708 if (unlikely(ecryptfs_verbosity > 0)) { 1709 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1710 crypt_stat->key_size); 1711 ecryptfs_dump_hex(crypt_stat->key, 1712 crypt_stat->key_size); 1713 } 1714 out: 1715 skcipher_request_free(req); 1716 return rc; 1717 } 1718 1719 /** 1720 * ecryptfs_parse_packet_set 1721 * @crypt_stat: The cryptographic context 1722 * @src: Virtual address of region of memory containing the packets 1723 * @src_size: Size of the packet set buffer 1724 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1725 * 1726 * Get crypt_stat to have the file's session key if the requisite key 1727 * is available to decrypt the session key. 1728 * 1729 * Returns Zero if a valid authentication token was retrieved and 1730 * processed; negative value for file not encrypted or for error 1731 * conditions. 1732 */ 1733 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1734 unsigned char *src, size_t src_size, 1735 struct dentry *ecryptfs_dentry) 1736 { 1737 size_t i = 0; 1738 size_t next_packet_is_auth_tok_packet; 1739 LIST_HEAD(auth_tok_list); 1740 struct ecryptfs_auth_tok *matching_auth_tok; 1741 struct ecryptfs_auth_tok *candidate_auth_tok; 1742 char *candidate_auth_tok_sig; 1743 size_t packet_size; 1744 struct ecryptfs_auth_tok *new_auth_tok; 1745 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1746 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1747 size_t tag_11_contents_size; 1748 size_t tag_11_packet_size; 1749 struct key *auth_tok_key = NULL; 1750 int rc = 0; 1751 1752 /* Parse the header to find as many packets as we can; these will be 1753 * added the our &auth_tok_list */ 1754 next_packet_is_auth_tok_packet = 1; 1755 while (next_packet_is_auth_tok_packet) { 1756 size_t max_packet_size; 1757 1758 if (i >= src_size) 1759 break; 1760 max_packet_size = src_size - i; 1761 1762 switch (src[i]) { 1763 case ECRYPTFS_TAG_3_PACKET_TYPE: 1764 rc = parse_tag_3_packet(crypt_stat, 1765 (unsigned char *)&src[i], 1766 &auth_tok_list, &new_auth_tok, 1767 &packet_size, max_packet_size); 1768 if (rc) { 1769 ecryptfs_printk(KERN_ERR, "Error parsing " 1770 "tag 3 packet\n"); 1771 rc = -EIO; 1772 goto out_wipe_list; 1773 } 1774 i += packet_size; 1775 if (i > src_size) { 1776 rc = -EIO; 1777 goto out_wipe_list; 1778 } 1779 rc = parse_tag_11_packet((unsigned char *)&src[i], 1780 sig_tmp_space, 1781 ECRYPTFS_SIG_SIZE, 1782 &tag_11_contents_size, 1783 &tag_11_packet_size, 1784 src_size - i); 1785 if (rc) { 1786 ecryptfs_printk(KERN_ERR, "No valid " 1787 "(ecryptfs-specific) literal " 1788 "packet containing " 1789 "authentication token " 1790 "signature found after " 1791 "tag 3 packet\n"); 1792 rc = -EIO; 1793 goto out_wipe_list; 1794 } 1795 i += tag_11_packet_size; 1796 if (i > src_size) { 1797 rc = -EIO; 1798 goto out_wipe_list; 1799 } 1800 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1801 ecryptfs_printk(KERN_ERR, "Expected " 1802 "signature of size [%d]; " 1803 "read size [%zd]\n", 1804 ECRYPTFS_SIG_SIZE, 1805 tag_11_contents_size); 1806 rc = -EIO; 1807 goto out_wipe_list; 1808 } 1809 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1810 sig_tmp_space, tag_11_contents_size); 1811 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1812 break; 1813 case ECRYPTFS_TAG_1_PACKET_TYPE: 1814 rc = parse_tag_1_packet(crypt_stat, 1815 (unsigned char *)&src[i], 1816 &auth_tok_list, &new_auth_tok, 1817 &packet_size, max_packet_size); 1818 if (rc) { 1819 ecryptfs_printk(KERN_ERR, "Error parsing " 1820 "tag 1 packet\n"); 1821 rc = -EIO; 1822 goto out_wipe_list; 1823 } 1824 i += packet_size; 1825 if (i > src_size) { 1826 rc = -EIO; 1827 goto out_wipe_list; 1828 } 1829 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1830 break; 1831 case ECRYPTFS_TAG_11_PACKET_TYPE: 1832 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1833 "(Tag 11 not allowed by itself)\n"); 1834 rc = -EIO; 1835 goto out_wipe_list; 1836 default: 1837 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1838 "of the file header; hex value of " 1839 "character is [0x%.2x]\n", i, src[i]); 1840 next_packet_is_auth_tok_packet = 0; 1841 } 1842 } 1843 if (list_empty(&auth_tok_list)) { 1844 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1845 "eCryptfs file; this is not supported in this version " 1846 "of the eCryptfs kernel module\n"); 1847 rc = -EINVAL; 1848 goto out; 1849 } 1850 /* auth_tok_list contains the set of authentication tokens 1851 * parsed from the metadata. We need to find a matching 1852 * authentication token that has the secret component(s) 1853 * necessary to decrypt the EFEK in the auth_tok parsed from 1854 * the metadata. There may be several potential matches, but 1855 * just one will be sufficient to decrypt to get the FEK. */ 1856 find_next_matching_auth_tok: 1857 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1858 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1859 if (unlikely(ecryptfs_verbosity > 0)) { 1860 ecryptfs_printk(KERN_DEBUG, 1861 "Considering candidate auth tok:\n"); 1862 ecryptfs_dump_auth_tok(candidate_auth_tok); 1863 } 1864 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1865 candidate_auth_tok); 1866 if (rc) { 1867 printk(KERN_ERR 1868 "Unrecognized candidate auth tok type: [%d]\n", 1869 candidate_auth_tok->token_type); 1870 rc = -EINVAL; 1871 goto out_wipe_list; 1872 } 1873 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1874 &matching_auth_tok, 1875 crypt_stat->mount_crypt_stat, 1876 candidate_auth_tok_sig); 1877 if (!rc) 1878 goto found_matching_auth_tok; 1879 } 1880 ecryptfs_printk(KERN_ERR, 1881 "Could not find a usable authentication token\n"); 1882 rc = -EIO; 1883 goto out_wipe_list; 1884 found_matching_auth_tok: 1885 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1886 memcpy(&(candidate_auth_tok->token.private_key), 1887 &(matching_auth_tok->token.private_key), 1888 sizeof(struct ecryptfs_private_key)); 1889 up_write(&(auth_tok_key->sem)); 1890 key_put(auth_tok_key); 1891 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1892 crypt_stat); 1893 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1894 memcpy(&(candidate_auth_tok->token.password), 1895 &(matching_auth_tok->token.password), 1896 sizeof(struct ecryptfs_password)); 1897 up_write(&(auth_tok_key->sem)); 1898 key_put(auth_tok_key); 1899 rc = decrypt_passphrase_encrypted_session_key( 1900 candidate_auth_tok, crypt_stat); 1901 } else { 1902 up_write(&(auth_tok_key->sem)); 1903 key_put(auth_tok_key); 1904 rc = -EINVAL; 1905 } 1906 if (rc) { 1907 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1908 1909 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1910 "session key for authentication token with sig " 1911 "[%.*s]; rc = [%d]. Removing auth tok " 1912 "candidate from the list and searching for " 1913 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1914 candidate_auth_tok_sig, rc); 1915 list_for_each_entry_safe(auth_tok_list_item, 1916 auth_tok_list_item_tmp, 1917 &auth_tok_list, list) { 1918 if (candidate_auth_tok 1919 == &auth_tok_list_item->auth_tok) { 1920 list_del(&auth_tok_list_item->list); 1921 kmem_cache_free( 1922 ecryptfs_auth_tok_list_item_cache, 1923 auth_tok_list_item); 1924 goto find_next_matching_auth_tok; 1925 } 1926 } 1927 BUG(); 1928 } 1929 rc = ecryptfs_compute_root_iv(crypt_stat); 1930 if (rc) { 1931 ecryptfs_printk(KERN_ERR, "Error computing " 1932 "the root IV\n"); 1933 goto out_wipe_list; 1934 } 1935 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1936 if (rc) { 1937 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1938 "context for cipher [%s]; rc = [%d]\n", 1939 crypt_stat->cipher, rc); 1940 } 1941 out_wipe_list: 1942 wipe_auth_tok_list(&auth_tok_list); 1943 out: 1944 return rc; 1945 } 1946 1947 static int 1948 pki_encrypt_session_key(struct key *auth_tok_key, 1949 struct ecryptfs_auth_tok *auth_tok, 1950 struct ecryptfs_crypt_stat *crypt_stat, 1951 struct ecryptfs_key_record *key_rec) 1952 { 1953 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1954 char *payload = NULL; 1955 size_t payload_len = 0; 1956 struct ecryptfs_message *msg; 1957 int rc; 1958 1959 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1960 ecryptfs_code_for_cipher_string( 1961 crypt_stat->cipher, 1962 crypt_stat->key_size), 1963 crypt_stat, &payload, &payload_len); 1964 up_write(&(auth_tok_key->sem)); 1965 key_put(auth_tok_key); 1966 if (rc) { 1967 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1968 goto out; 1969 } 1970 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1971 if (rc) { 1972 ecryptfs_printk(KERN_ERR, "Error sending message to " 1973 "ecryptfsd: %d\n", rc); 1974 goto out; 1975 } 1976 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1977 if (rc) { 1978 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 1979 "from the user space daemon\n"); 1980 rc = -EIO; 1981 goto out; 1982 } 1983 rc = parse_tag_67_packet(key_rec, msg); 1984 if (rc) 1985 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 1986 kfree(msg); 1987 out: 1988 kfree(payload); 1989 return rc; 1990 } 1991 /** 1992 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 1993 * @dest: Buffer into which to write the packet 1994 * @remaining_bytes: Maximum number of bytes that can be writtn 1995 * @auth_tok_key: The authentication token key to unlock and put when done with 1996 * @auth_tok 1997 * @auth_tok: The authentication token used for generating the tag 1 packet 1998 * @crypt_stat: The cryptographic context 1999 * @key_rec: The key record struct for the tag 1 packet 2000 * @packet_size: This function will write the number of bytes that end 2001 * up constituting the packet; set to zero on error 2002 * 2003 * Returns zero on success; non-zero on error. 2004 */ 2005 static int 2006 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2007 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2008 struct ecryptfs_crypt_stat *crypt_stat, 2009 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2010 { 2011 size_t i; 2012 size_t encrypted_session_key_valid = 0; 2013 size_t packet_size_length; 2014 size_t max_packet_size; 2015 int rc = 0; 2016 2017 (*packet_size) = 0; 2018 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2019 ECRYPTFS_SIG_SIZE); 2020 encrypted_session_key_valid = 0; 2021 for (i = 0; i < crypt_stat->key_size; i++) 2022 encrypted_session_key_valid |= 2023 auth_tok->session_key.encrypted_key[i]; 2024 if (encrypted_session_key_valid) { 2025 memcpy(key_rec->enc_key, 2026 auth_tok->session_key.encrypted_key, 2027 auth_tok->session_key.encrypted_key_size); 2028 up_write(&(auth_tok_key->sem)); 2029 key_put(auth_tok_key); 2030 goto encrypted_session_key_set; 2031 } 2032 if (auth_tok->session_key.encrypted_key_size == 0) 2033 auth_tok->session_key.encrypted_key_size = 2034 auth_tok->token.private_key.key_size; 2035 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2036 key_rec); 2037 if (rc) { 2038 printk(KERN_ERR "Failed to encrypt session key via a key " 2039 "module; rc = [%d]\n", rc); 2040 goto out; 2041 } 2042 if (ecryptfs_verbosity > 0) { 2043 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2044 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2045 } 2046 encrypted_session_key_set: 2047 /* This format is inspired by OpenPGP; see RFC 2440 2048 * packet tag 1 */ 2049 max_packet_size = (1 /* Tag 1 identifier */ 2050 + 3 /* Max Tag 1 packet size */ 2051 + 1 /* Version */ 2052 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2053 + 1 /* Cipher identifier */ 2054 + key_rec->enc_key_size); /* Encrypted key size */ 2055 if (max_packet_size > (*remaining_bytes)) { 2056 printk(KERN_ERR "Packet length larger than maximum allowable; " 2057 "need up to [%td] bytes, but there are only [%td] " 2058 "available\n", max_packet_size, (*remaining_bytes)); 2059 rc = -EINVAL; 2060 goto out; 2061 } 2062 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2063 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2064 (max_packet_size - 4), 2065 &packet_size_length); 2066 if (rc) { 2067 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2068 "header; cannot generate packet length\n"); 2069 goto out; 2070 } 2071 (*packet_size) += packet_size_length; 2072 dest[(*packet_size)++] = 0x03; /* version 3 */ 2073 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2074 (*packet_size) += ECRYPTFS_SIG_SIZE; 2075 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2076 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2077 key_rec->enc_key_size); 2078 (*packet_size) += key_rec->enc_key_size; 2079 out: 2080 if (rc) 2081 (*packet_size) = 0; 2082 else 2083 (*remaining_bytes) -= (*packet_size); 2084 return rc; 2085 } 2086 2087 /** 2088 * write_tag_11_packet 2089 * @dest: Target into which Tag 11 packet is to be written 2090 * @remaining_bytes: Maximum packet length 2091 * @contents: Byte array of contents to copy in 2092 * @contents_length: Number of bytes in contents 2093 * @packet_length: Length of the Tag 11 packet written; zero on error 2094 * 2095 * Returns zero on success; non-zero on error. 2096 */ 2097 static int 2098 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2099 size_t contents_length, size_t *packet_length) 2100 { 2101 size_t packet_size_length; 2102 size_t max_packet_size; 2103 int rc = 0; 2104 2105 (*packet_length) = 0; 2106 /* This format is inspired by OpenPGP; see RFC 2440 2107 * packet tag 11 */ 2108 max_packet_size = (1 /* Tag 11 identifier */ 2109 + 3 /* Max Tag 11 packet size */ 2110 + 1 /* Binary format specifier */ 2111 + 1 /* Filename length */ 2112 + 8 /* Filename ("_CONSOLE") */ 2113 + 4 /* Modification date */ 2114 + contents_length); /* Literal data */ 2115 if (max_packet_size > (*remaining_bytes)) { 2116 printk(KERN_ERR "Packet length larger than maximum allowable; " 2117 "need up to [%td] bytes, but there are only [%td] " 2118 "available\n", max_packet_size, (*remaining_bytes)); 2119 rc = -EINVAL; 2120 goto out; 2121 } 2122 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2123 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2124 (max_packet_size - 4), 2125 &packet_size_length); 2126 if (rc) { 2127 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2128 "generate packet length. rc = [%d]\n", rc); 2129 goto out; 2130 } 2131 (*packet_length) += packet_size_length; 2132 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2133 dest[(*packet_length)++] = 8; 2134 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2135 (*packet_length) += 8; 2136 memset(&dest[(*packet_length)], 0x00, 4); 2137 (*packet_length) += 4; 2138 memcpy(&dest[(*packet_length)], contents, contents_length); 2139 (*packet_length) += contents_length; 2140 out: 2141 if (rc) 2142 (*packet_length) = 0; 2143 else 2144 (*remaining_bytes) -= (*packet_length); 2145 return rc; 2146 } 2147 2148 /** 2149 * write_tag_3_packet 2150 * @dest: Buffer into which to write the packet 2151 * @remaining_bytes: Maximum number of bytes that can be written 2152 * @auth_tok: Authentication token 2153 * @crypt_stat: The cryptographic context 2154 * @key_rec: encrypted key 2155 * @packet_size: This function will write the number of bytes that end 2156 * up constituting the packet; set to zero on error 2157 * 2158 * Returns zero on success; non-zero on error. 2159 */ 2160 static int 2161 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2162 struct ecryptfs_auth_tok *auth_tok, 2163 struct ecryptfs_crypt_stat *crypt_stat, 2164 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2165 { 2166 size_t i; 2167 size_t encrypted_session_key_valid = 0; 2168 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2169 struct scatterlist dst_sg[2]; 2170 struct scatterlist src_sg[2]; 2171 struct mutex *tfm_mutex = NULL; 2172 u8 cipher_code; 2173 size_t packet_size_length; 2174 size_t max_packet_size; 2175 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2176 crypt_stat->mount_crypt_stat; 2177 struct crypto_skcipher *tfm; 2178 struct skcipher_request *req; 2179 int rc = 0; 2180 2181 (*packet_size) = 0; 2182 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2183 ECRYPTFS_SIG_SIZE); 2184 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 2185 crypt_stat->cipher); 2186 if (unlikely(rc)) { 2187 printk(KERN_ERR "Internal error whilst attempting to get " 2188 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2189 crypt_stat->cipher, rc); 2190 goto out; 2191 } 2192 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2193 printk(KERN_WARNING "No key size specified at mount; " 2194 "defaulting to [%d]\n", 2195 crypto_skcipher_max_keysize(tfm)); 2196 mount_crypt_stat->global_default_cipher_key_size = 2197 crypto_skcipher_max_keysize(tfm); 2198 } 2199 if (crypt_stat->key_size == 0) 2200 crypt_stat->key_size = 2201 mount_crypt_stat->global_default_cipher_key_size; 2202 if (auth_tok->session_key.encrypted_key_size == 0) 2203 auth_tok->session_key.encrypted_key_size = 2204 crypt_stat->key_size; 2205 if (crypt_stat->key_size == 24 2206 && strcmp("aes", crypt_stat->cipher) == 0) { 2207 memset((crypt_stat->key + 24), 0, 8); 2208 auth_tok->session_key.encrypted_key_size = 32; 2209 } else 2210 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2211 key_rec->enc_key_size = 2212 auth_tok->session_key.encrypted_key_size; 2213 encrypted_session_key_valid = 0; 2214 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2215 encrypted_session_key_valid |= 2216 auth_tok->session_key.encrypted_key[i]; 2217 if (encrypted_session_key_valid) { 2218 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2219 "using auth_tok->session_key.encrypted_key, " 2220 "where key_rec->enc_key_size = [%zd]\n", 2221 key_rec->enc_key_size); 2222 memcpy(key_rec->enc_key, 2223 auth_tok->session_key.encrypted_key, 2224 key_rec->enc_key_size); 2225 goto encrypted_session_key_set; 2226 } 2227 if (auth_tok->token.password.flags & 2228 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2229 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2230 "session key encryption key of size [%d]\n", 2231 auth_tok->token.password. 2232 session_key_encryption_key_bytes); 2233 memcpy(session_key_encryption_key, 2234 auth_tok->token.password.session_key_encryption_key, 2235 crypt_stat->key_size); 2236 ecryptfs_printk(KERN_DEBUG, 2237 "Cached session key encryption key:\n"); 2238 if (ecryptfs_verbosity > 0) 2239 ecryptfs_dump_hex(session_key_encryption_key, 16); 2240 } 2241 if (unlikely(ecryptfs_verbosity > 0)) { 2242 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2243 ecryptfs_dump_hex(session_key_encryption_key, 16); 2244 } 2245 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2246 src_sg, 2); 2247 if (rc < 1 || rc > 2) { 2248 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2249 "for crypt_stat session key; expected rc = 1; " 2250 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2251 rc, key_rec->enc_key_size); 2252 rc = -ENOMEM; 2253 goto out; 2254 } 2255 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2256 dst_sg, 2); 2257 if (rc < 1 || rc > 2) { 2258 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2259 "for crypt_stat encrypted session key; " 2260 "expected rc = 1; got rc = [%d]. " 2261 "key_rec->enc_key_size = [%zd]\n", rc, 2262 key_rec->enc_key_size); 2263 rc = -ENOMEM; 2264 goto out; 2265 } 2266 mutex_lock(tfm_mutex); 2267 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key, 2268 crypt_stat->key_size); 2269 if (rc < 0) { 2270 mutex_unlock(tfm_mutex); 2271 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2272 "context; rc = [%d]\n", rc); 2273 goto out; 2274 } 2275 2276 req = skcipher_request_alloc(tfm, GFP_KERNEL); 2277 if (!req) { 2278 mutex_unlock(tfm_mutex); 2279 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " 2280 "attempting to skcipher_request_alloc for " 2281 "%s\n", crypto_skcipher_driver_name(tfm)); 2282 rc = -ENOMEM; 2283 goto out; 2284 } 2285 2286 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 2287 NULL, NULL); 2288 2289 rc = 0; 2290 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2291 crypt_stat->key_size); 2292 skcipher_request_set_crypt(req, src_sg, dst_sg, 2293 (*key_rec).enc_key_size, NULL); 2294 rc = crypto_skcipher_encrypt(req); 2295 mutex_unlock(tfm_mutex); 2296 skcipher_request_free(req); 2297 if (rc) { 2298 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2299 goto out; 2300 } 2301 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2302 if (ecryptfs_verbosity > 0) { 2303 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2304 key_rec->enc_key_size); 2305 ecryptfs_dump_hex(key_rec->enc_key, 2306 key_rec->enc_key_size); 2307 } 2308 encrypted_session_key_set: 2309 /* This format is inspired by OpenPGP; see RFC 2440 2310 * packet tag 3 */ 2311 max_packet_size = (1 /* Tag 3 identifier */ 2312 + 3 /* Max Tag 3 packet size */ 2313 + 1 /* Version */ 2314 + 1 /* Cipher code */ 2315 + 1 /* S2K specifier */ 2316 + 1 /* Hash identifier */ 2317 + ECRYPTFS_SALT_SIZE /* Salt */ 2318 + 1 /* Hash iterations */ 2319 + key_rec->enc_key_size); /* Encrypted key size */ 2320 if (max_packet_size > (*remaining_bytes)) { 2321 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2322 "there are only [%td] available\n", max_packet_size, 2323 (*remaining_bytes)); 2324 rc = -EINVAL; 2325 goto out; 2326 } 2327 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2328 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2329 * to get the number of octets in the actual Tag 3 packet */ 2330 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2331 (max_packet_size - 4), 2332 &packet_size_length); 2333 if (rc) { 2334 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2335 "generate packet length. rc = [%d]\n", rc); 2336 goto out; 2337 } 2338 (*packet_size) += packet_size_length; 2339 dest[(*packet_size)++] = 0x04; /* version 4 */ 2340 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2341 * specified with strings */ 2342 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2343 crypt_stat->key_size); 2344 if (cipher_code == 0) { 2345 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2346 "cipher [%s]\n", crypt_stat->cipher); 2347 rc = -EINVAL; 2348 goto out; 2349 } 2350 dest[(*packet_size)++] = cipher_code; 2351 dest[(*packet_size)++] = 0x03; /* S2K */ 2352 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2353 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2354 ECRYPTFS_SALT_SIZE); 2355 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2356 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2357 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2358 key_rec->enc_key_size); 2359 (*packet_size) += key_rec->enc_key_size; 2360 out: 2361 if (rc) 2362 (*packet_size) = 0; 2363 else 2364 (*remaining_bytes) -= (*packet_size); 2365 return rc; 2366 } 2367 2368 struct kmem_cache *ecryptfs_key_record_cache; 2369 2370 /** 2371 * ecryptfs_generate_key_packet_set 2372 * @dest_base: Virtual address from which to write the key record set 2373 * @crypt_stat: The cryptographic context from which the 2374 * authentication tokens will be retrieved 2375 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2376 * for the global parameters 2377 * @len: The amount written 2378 * @max: The maximum amount of data allowed to be written 2379 * 2380 * Generates a key packet set and writes it to the virtual address 2381 * passed in. 2382 * 2383 * Returns zero on success; non-zero on error. 2384 */ 2385 int 2386 ecryptfs_generate_key_packet_set(char *dest_base, 2387 struct ecryptfs_crypt_stat *crypt_stat, 2388 struct dentry *ecryptfs_dentry, size_t *len, 2389 size_t max) 2390 { 2391 struct ecryptfs_auth_tok *auth_tok; 2392 struct key *auth_tok_key = NULL; 2393 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2394 &ecryptfs_superblock_to_private( 2395 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2396 size_t written; 2397 struct ecryptfs_key_record *key_rec; 2398 struct ecryptfs_key_sig *key_sig; 2399 int rc = 0; 2400 2401 (*len) = 0; 2402 mutex_lock(&crypt_stat->keysig_list_mutex); 2403 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2404 if (!key_rec) { 2405 rc = -ENOMEM; 2406 goto out; 2407 } 2408 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2409 crypt_stat_list) { 2410 memset(key_rec, 0, sizeof(*key_rec)); 2411 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2412 &auth_tok, 2413 mount_crypt_stat, 2414 key_sig->keysig); 2415 if (rc) { 2416 printk(KERN_WARNING "Unable to retrieve auth tok with " 2417 "sig = [%s]\n", key_sig->keysig); 2418 rc = process_find_global_auth_tok_for_sig_err(rc); 2419 goto out_free; 2420 } 2421 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2422 rc = write_tag_3_packet((dest_base + (*len)), 2423 &max, auth_tok, 2424 crypt_stat, key_rec, 2425 &written); 2426 up_write(&(auth_tok_key->sem)); 2427 key_put(auth_tok_key); 2428 if (rc) { 2429 ecryptfs_printk(KERN_WARNING, "Error " 2430 "writing tag 3 packet\n"); 2431 goto out_free; 2432 } 2433 (*len) += written; 2434 /* Write auth tok signature packet */ 2435 rc = write_tag_11_packet((dest_base + (*len)), &max, 2436 key_rec->sig, 2437 ECRYPTFS_SIG_SIZE, &written); 2438 if (rc) { 2439 ecryptfs_printk(KERN_ERR, "Error writing " 2440 "auth tok signature packet\n"); 2441 goto out_free; 2442 } 2443 (*len) += written; 2444 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2445 rc = write_tag_1_packet(dest_base + (*len), &max, 2446 auth_tok_key, auth_tok, 2447 crypt_stat, key_rec, &written); 2448 if (rc) { 2449 ecryptfs_printk(KERN_WARNING, "Error " 2450 "writing tag 1 packet\n"); 2451 goto out_free; 2452 } 2453 (*len) += written; 2454 } else { 2455 up_write(&(auth_tok_key->sem)); 2456 key_put(auth_tok_key); 2457 ecryptfs_printk(KERN_WARNING, "Unsupported " 2458 "authentication token type\n"); 2459 rc = -EINVAL; 2460 goto out_free; 2461 } 2462 } 2463 if (likely(max > 0)) { 2464 dest_base[(*len)] = 0x00; 2465 } else { 2466 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2467 rc = -EIO; 2468 } 2469 out_free: 2470 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2471 out: 2472 if (rc) 2473 (*len) = 0; 2474 mutex_unlock(&crypt_stat->keysig_list_mutex); 2475 return rc; 2476 } 2477 2478 struct kmem_cache *ecryptfs_key_sig_cache; 2479 2480 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2481 { 2482 struct ecryptfs_key_sig *new_key_sig; 2483 2484 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2485 if (!new_key_sig) 2486 return -ENOMEM; 2487 2488 strscpy(new_key_sig->keysig, sig); 2489 /* Caller must hold keysig_list_mutex */ 2490 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2491 2492 return 0; 2493 } 2494 2495 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2496 2497 int 2498 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2499 char *sig, u32 global_auth_tok_flags) 2500 { 2501 struct ecryptfs_global_auth_tok *new_auth_tok; 2502 2503 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2504 GFP_KERNEL); 2505 if (!new_auth_tok) 2506 return -ENOMEM; 2507 2508 strscpy(new_auth_tok->sig, sig); 2509 new_auth_tok->flags = global_auth_tok_flags; 2510 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2511 list_add(&new_auth_tok->mount_crypt_stat_list, 2512 &mount_crypt_stat->global_auth_tok_list); 2513 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2514 return 0; 2515 } 2516 2517