1 /** 2 * eCryptfs: Linux filesystem encryption layer 3 * In-kernel key management code. Includes functions to parse and 4 * write authentication token-related packets with the underlying 5 * file. 6 * 7 * Copyright (C) 2004-2006 International Business Machines Corp. 8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> 9 * Michael C. Thompson <mcthomps@us.ibm.com> 10 * Trevor S. Highland <trevor.highland@gmail.com> 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License as 14 * published by the Free Software Foundation; either version 2 of the 15 * License, or (at your option) any later version. 16 * 17 * This program is distributed in the hope that it will be useful, but 18 * WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20 * General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License 23 * along with this program; if not, write to the Free Software 24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 25 * 02111-1307, USA. 26 */ 27 28 #include <crypto/hash.h> 29 #include <crypto/skcipher.h> 30 #include <linux/string.h> 31 #include <linux/pagemap.h> 32 #include <linux/key.h> 33 #include <linux/random.h> 34 #include <linux/scatterlist.h> 35 #include <linux/slab.h> 36 #include "ecryptfs_kernel.h" 37 38 /** 39 * request_key returned an error instead of a valid key address; 40 * determine the type of error, make appropriate log entries, and 41 * return an error code. 42 */ 43 static int process_request_key_err(long err_code) 44 { 45 int rc = 0; 46 47 switch (err_code) { 48 case -ENOKEY: 49 ecryptfs_printk(KERN_WARNING, "No key\n"); 50 rc = -ENOENT; 51 break; 52 case -EKEYEXPIRED: 53 ecryptfs_printk(KERN_WARNING, "Key expired\n"); 54 rc = -ETIME; 55 break; 56 case -EKEYREVOKED: 57 ecryptfs_printk(KERN_WARNING, "Key revoked\n"); 58 rc = -EINVAL; 59 break; 60 default: 61 ecryptfs_printk(KERN_WARNING, "Unknown error code: " 62 "[0x%.16lx]\n", err_code); 63 rc = -EINVAL; 64 } 65 return rc; 66 } 67 68 static int process_find_global_auth_tok_for_sig_err(int err_code) 69 { 70 int rc = err_code; 71 72 switch (err_code) { 73 case -ENOENT: 74 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n"); 75 break; 76 case -EINVAL: 77 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n"); 78 break; 79 default: 80 rc = process_request_key_err(err_code); 81 break; 82 } 83 return rc; 84 } 85 86 /** 87 * ecryptfs_parse_packet_length 88 * @data: Pointer to memory containing length at offset 89 * @size: This function writes the decoded size to this memory 90 * address; zero on error 91 * @length_size: The number of bytes occupied by the encoded length 92 * 93 * Returns zero on success; non-zero on error 94 */ 95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, 96 size_t *length_size) 97 { 98 int rc = 0; 99 100 (*length_size) = 0; 101 (*size) = 0; 102 if (data[0] < 192) { 103 /* One-byte length */ 104 (*size) = data[0]; 105 (*length_size) = 1; 106 } else if (data[0] < 224) { 107 /* Two-byte length */ 108 (*size) = (data[0] - 192) * 256; 109 (*size) += data[1] + 192; 110 (*length_size) = 2; 111 } else if (data[0] == 255) { 112 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 113 ecryptfs_printk(KERN_ERR, "Five-byte packet length not " 114 "supported\n"); 115 rc = -EINVAL; 116 goto out; 117 } else { 118 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n"); 119 rc = -EINVAL; 120 goto out; 121 } 122 out: 123 return rc; 124 } 125 126 /** 127 * ecryptfs_write_packet_length 128 * @dest: The byte array target into which to write the length. Must 129 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated. 130 * @size: The length to write. 131 * @packet_size_length: The number of bytes used to encode the packet 132 * length is written to this address. 133 * 134 * Returns zero on success; non-zero on error. 135 */ 136 int ecryptfs_write_packet_length(char *dest, size_t size, 137 size_t *packet_size_length) 138 { 139 int rc = 0; 140 141 if (size < 192) { 142 dest[0] = size; 143 (*packet_size_length) = 1; 144 } else if (size < 65536) { 145 dest[0] = (((size - 192) / 256) + 192); 146 dest[1] = ((size - 192) % 256); 147 (*packet_size_length) = 2; 148 } else { 149 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ 150 rc = -EINVAL; 151 ecryptfs_printk(KERN_WARNING, 152 "Unsupported packet size: [%zd]\n", size); 153 } 154 return rc; 155 } 156 157 static int 158 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key, 159 char **packet, size_t *packet_len) 160 { 161 size_t i = 0; 162 size_t data_len; 163 size_t packet_size_len; 164 char *message; 165 int rc; 166 167 /* 168 * ***** TAG 64 Packet Format ***** 169 * | Content Type | 1 byte | 170 * | Key Identifier Size | 1 or 2 bytes | 171 * | Key Identifier | arbitrary | 172 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 173 * | Encrypted File Encryption Key | arbitrary | 174 */ 175 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX 176 + session_key->encrypted_key_size); 177 *packet = kmalloc(data_len, GFP_KERNEL); 178 message = *packet; 179 if (!message) { 180 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 181 rc = -ENOMEM; 182 goto out; 183 } 184 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE; 185 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 186 &packet_size_len); 187 if (rc) { 188 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 189 "header; cannot generate packet length\n"); 190 goto out; 191 } 192 i += packet_size_len; 193 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 194 i += ECRYPTFS_SIG_SIZE_HEX; 195 rc = ecryptfs_write_packet_length(&message[i], 196 session_key->encrypted_key_size, 197 &packet_size_len); 198 if (rc) { 199 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " 200 "header; cannot generate packet length\n"); 201 goto out; 202 } 203 i += packet_size_len; 204 memcpy(&message[i], session_key->encrypted_key, 205 session_key->encrypted_key_size); 206 i += session_key->encrypted_key_size; 207 *packet_len = i; 208 out: 209 return rc; 210 } 211 212 static int 213 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code, 214 struct ecryptfs_message *msg) 215 { 216 size_t i = 0; 217 char *data; 218 size_t data_len; 219 size_t m_size; 220 size_t message_len; 221 u16 checksum = 0; 222 u16 expected_checksum = 0; 223 int rc; 224 225 /* 226 * ***** TAG 65 Packet Format ***** 227 * | Content Type | 1 byte | 228 * | Status Indicator | 1 byte | 229 * | File Encryption Key Size | 1 or 2 bytes | 230 * | File Encryption Key | arbitrary | 231 */ 232 message_len = msg->data_len; 233 data = msg->data; 234 if (message_len < 4) { 235 rc = -EIO; 236 goto out; 237 } 238 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) { 239 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n"); 240 rc = -EIO; 241 goto out; 242 } 243 if (data[i++]) { 244 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value " 245 "[%d]\n", data[i-1]); 246 rc = -EIO; 247 goto out; 248 } 249 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len); 250 if (rc) { 251 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 252 "rc = [%d]\n", rc); 253 goto out; 254 } 255 i += data_len; 256 if (message_len < (i + m_size)) { 257 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd " 258 "is shorter than expected\n"); 259 rc = -EIO; 260 goto out; 261 } 262 if (m_size < 3) { 263 ecryptfs_printk(KERN_ERR, 264 "The decrypted key is not long enough to " 265 "include a cipher code and checksum\n"); 266 rc = -EIO; 267 goto out; 268 } 269 *cipher_code = data[i++]; 270 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */ 271 session_key->decrypted_key_size = m_size - 3; 272 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) { 273 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than " 274 "the maximum key size [%d]\n", 275 session_key->decrypted_key_size, 276 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 277 rc = -EIO; 278 goto out; 279 } 280 memcpy(session_key->decrypted_key, &data[i], 281 session_key->decrypted_key_size); 282 i += session_key->decrypted_key_size; 283 expected_checksum += (unsigned char)(data[i++]) << 8; 284 expected_checksum += (unsigned char)(data[i++]); 285 for (i = 0; i < session_key->decrypted_key_size; i++) 286 checksum += session_key->decrypted_key[i]; 287 if (expected_checksum != checksum) { 288 ecryptfs_printk(KERN_ERR, "Invalid checksum for file " 289 "encryption key; expected [%x]; calculated " 290 "[%x]\n", expected_checksum, checksum); 291 rc = -EIO; 292 } 293 out: 294 return rc; 295 } 296 297 298 static int 299 write_tag_66_packet(char *signature, u8 cipher_code, 300 struct ecryptfs_crypt_stat *crypt_stat, char **packet, 301 size_t *packet_len) 302 { 303 size_t i = 0; 304 size_t j; 305 size_t data_len; 306 size_t checksum = 0; 307 size_t packet_size_len; 308 char *message; 309 int rc; 310 311 /* 312 * ***** TAG 66 Packet Format ***** 313 * | Content Type | 1 byte | 314 * | Key Identifier Size | 1 or 2 bytes | 315 * | Key Identifier | arbitrary | 316 * | File Encryption Key Size | 1 or 2 bytes | 317 * | File Encryption Key | arbitrary | 318 */ 319 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); 320 *packet = kmalloc(data_len, GFP_KERNEL); 321 message = *packet; 322 if (!message) { 323 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); 324 rc = -ENOMEM; 325 goto out; 326 } 327 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; 328 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, 329 &packet_size_len); 330 if (rc) { 331 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 332 "header; cannot generate packet length\n"); 333 goto out; 334 } 335 i += packet_size_len; 336 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); 337 i += ECRYPTFS_SIG_SIZE_HEX; 338 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */ 339 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, 340 &packet_size_len); 341 if (rc) { 342 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " 343 "header; cannot generate packet length\n"); 344 goto out; 345 } 346 i += packet_size_len; 347 message[i++] = cipher_code; 348 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); 349 i += crypt_stat->key_size; 350 for (j = 0; j < crypt_stat->key_size; j++) 351 checksum += crypt_stat->key[j]; 352 message[i++] = (checksum / 256) % 256; 353 message[i++] = (checksum % 256); 354 *packet_len = i; 355 out: 356 return rc; 357 } 358 359 static int 360 parse_tag_67_packet(struct ecryptfs_key_record *key_rec, 361 struct ecryptfs_message *msg) 362 { 363 size_t i = 0; 364 char *data; 365 size_t data_len; 366 size_t message_len; 367 int rc; 368 369 /* 370 * ***** TAG 65 Packet Format ***** 371 * | Content Type | 1 byte | 372 * | Status Indicator | 1 byte | 373 * | Encrypted File Encryption Key Size | 1 or 2 bytes | 374 * | Encrypted File Encryption Key | arbitrary | 375 */ 376 message_len = msg->data_len; 377 data = msg->data; 378 /* verify that everything through the encrypted FEK size is present */ 379 if (message_len < 4) { 380 rc = -EIO; 381 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " 382 "message length is [%d]\n", __func__, message_len, 4); 383 goto out; 384 } 385 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { 386 rc = -EIO; 387 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", 388 __func__); 389 goto out; 390 } 391 if (data[i++]) { 392 rc = -EIO; 393 printk(KERN_ERR "%s: Status indicator has non zero " 394 "value [%d]\n", __func__, data[i-1]); 395 396 goto out; 397 } 398 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, 399 &data_len); 400 if (rc) { 401 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " 402 "rc = [%d]\n", rc); 403 goto out; 404 } 405 i += data_len; 406 if (message_len < (i + key_rec->enc_key_size)) { 407 rc = -EIO; 408 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", 409 __func__, message_len, (i + key_rec->enc_key_size)); 410 goto out; 411 } 412 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 413 rc = -EIO; 414 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " 415 "the maximum key size [%d]\n", __func__, 416 key_rec->enc_key_size, 417 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); 418 goto out; 419 } 420 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); 421 out: 422 return rc; 423 } 424 425 /** 426 * ecryptfs_verify_version 427 * @version: The version number to confirm 428 * 429 * Returns zero on good version; non-zero otherwise 430 */ 431 static int ecryptfs_verify_version(u16 version) 432 { 433 int rc = 0; 434 unsigned char major; 435 unsigned char minor; 436 437 major = ((version >> 8) & 0xFF); 438 minor = (version & 0xFF); 439 if (major != ECRYPTFS_VERSION_MAJOR) { 440 ecryptfs_printk(KERN_ERR, "Major version number mismatch. " 441 "Expected [%d]; got [%d]\n", 442 ECRYPTFS_VERSION_MAJOR, major); 443 rc = -EINVAL; 444 goto out; 445 } 446 if (minor != ECRYPTFS_VERSION_MINOR) { 447 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " 448 "Expected [%d]; got [%d]\n", 449 ECRYPTFS_VERSION_MINOR, minor); 450 rc = -EINVAL; 451 goto out; 452 } 453 out: 454 return rc; 455 } 456 457 /** 458 * ecryptfs_verify_auth_tok_from_key 459 * @auth_tok_key: key containing the authentication token 460 * @auth_tok: authentication token 461 * 462 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or 463 * -EKEYREVOKED if the key was revoked before we acquired its semaphore. 464 */ 465 static int 466 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, 467 struct ecryptfs_auth_tok **auth_tok) 468 { 469 int rc = 0; 470 471 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); 472 if (IS_ERR(*auth_tok)) { 473 rc = PTR_ERR(*auth_tok); 474 *auth_tok = NULL; 475 goto out; 476 } 477 478 if (ecryptfs_verify_version((*auth_tok)->version)) { 479 printk(KERN_ERR "Data structure version mismatch. Userspace " 480 "tools must match eCryptfs kernel module with major " 481 "version [%d] and minor version [%d]\n", 482 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); 483 rc = -EINVAL; 484 goto out; 485 } 486 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD 487 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { 488 printk(KERN_ERR "Invalid auth_tok structure " 489 "returned from key query\n"); 490 rc = -EINVAL; 491 goto out; 492 } 493 out: 494 return rc; 495 } 496 497 static int 498 ecryptfs_find_global_auth_tok_for_sig( 499 struct key **auth_tok_key, 500 struct ecryptfs_auth_tok **auth_tok, 501 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) 502 { 503 struct ecryptfs_global_auth_tok *walker; 504 int rc = 0; 505 506 (*auth_tok_key) = NULL; 507 (*auth_tok) = NULL; 508 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 509 list_for_each_entry(walker, 510 &mount_crypt_stat->global_auth_tok_list, 511 mount_crypt_stat_list) { 512 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) 513 continue; 514 515 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { 516 rc = -EINVAL; 517 goto out; 518 } 519 520 rc = key_validate(walker->global_auth_tok_key); 521 if (rc) { 522 if (rc == -EKEYEXPIRED) 523 goto out; 524 goto out_invalid_auth_tok; 525 } 526 527 down_write(&(walker->global_auth_tok_key->sem)); 528 rc = ecryptfs_verify_auth_tok_from_key( 529 walker->global_auth_tok_key, auth_tok); 530 if (rc) 531 goto out_invalid_auth_tok_unlock; 532 533 (*auth_tok_key) = walker->global_auth_tok_key; 534 key_get(*auth_tok_key); 535 goto out; 536 } 537 rc = -ENOENT; 538 goto out; 539 out_invalid_auth_tok_unlock: 540 up_write(&(walker->global_auth_tok_key->sem)); 541 out_invalid_auth_tok: 542 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); 543 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; 544 key_put(walker->global_auth_tok_key); 545 walker->global_auth_tok_key = NULL; 546 out: 547 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 548 return rc; 549 } 550 551 /** 552 * ecryptfs_find_auth_tok_for_sig 553 * @auth_tok: Set to the matching auth_tok; NULL if not found 554 * @crypt_stat: inode crypt_stat crypto context 555 * @sig: Sig of auth_tok to find 556 * 557 * For now, this function simply looks at the registered auth_tok's 558 * linked off the mount_crypt_stat, so all the auth_toks that can be 559 * used must be registered at mount time. This function could 560 * potentially try a lot harder to find auth_tok's (e.g., by calling 561 * out to ecryptfsd to dynamically retrieve an auth_tok object) so 562 * that static registration of auth_tok's will no longer be necessary. 563 * 564 * Returns zero on no error; non-zero on error 565 */ 566 static int 567 ecryptfs_find_auth_tok_for_sig( 568 struct key **auth_tok_key, 569 struct ecryptfs_auth_tok **auth_tok, 570 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 571 char *sig) 572 { 573 int rc = 0; 574 575 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, 576 mount_crypt_stat, sig); 577 if (rc == -ENOENT) { 578 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the 579 * mount_crypt_stat structure, we prevent to use auth toks that 580 * are not inserted through the ecryptfs_add_global_auth_tok 581 * function. 582 */ 583 if (mount_crypt_stat->flags 584 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) 585 return -EINVAL; 586 587 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, 588 sig); 589 } 590 return rc; 591 } 592 593 /** 594 * write_tag_70_packet can gobble a lot of stack space. We stuff most 595 * of the function's parameters in a kmalloc'd struct to help reduce 596 * eCryptfs' overall stack usage. 597 */ 598 struct ecryptfs_write_tag_70_packet_silly_stack { 599 u8 cipher_code; 600 size_t max_packet_size; 601 size_t packet_size_len; 602 size_t block_aligned_filename_size; 603 size_t block_size; 604 size_t i; 605 size_t j; 606 size_t num_rand_bytes; 607 struct mutex *tfm_mutex; 608 char *block_aligned_filename; 609 struct ecryptfs_auth_tok *auth_tok; 610 struct scatterlist src_sg[2]; 611 struct scatterlist dst_sg[2]; 612 struct crypto_skcipher *skcipher_tfm; 613 struct skcipher_request *skcipher_req; 614 char iv[ECRYPTFS_MAX_IV_BYTES]; 615 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 616 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; 617 struct crypto_shash *hash_tfm; 618 struct shash_desc *hash_desc; 619 }; 620 621 /** 622 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK 623 * @filename: NULL-terminated filename string 624 * 625 * This is the simplest mechanism for achieving filename encryption in 626 * eCryptfs. It encrypts the given filename with the mount-wide 627 * filename encryption key (FNEK) and stores it in a packet to @dest, 628 * which the callee will encode and write directly into the dentry 629 * name. 630 */ 631 int 632 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, 633 size_t *packet_size, 634 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 635 char *filename, size_t filename_size) 636 { 637 struct ecryptfs_write_tag_70_packet_silly_stack *s; 638 struct key *auth_tok_key = NULL; 639 int rc = 0; 640 641 s = kzalloc(sizeof(*s), GFP_KERNEL); 642 if (!s) { 643 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 644 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 645 return -ENOMEM; 646 } 647 (*packet_size) = 0; 648 rc = ecryptfs_find_auth_tok_for_sig( 649 &auth_tok_key, 650 &s->auth_tok, mount_crypt_stat, 651 mount_crypt_stat->global_default_fnek_sig); 652 if (rc) { 653 printk(KERN_ERR "%s: Error attempting to find auth tok for " 654 "fnek sig [%s]; rc = [%d]\n", __func__, 655 mount_crypt_stat->global_default_fnek_sig, rc); 656 goto out; 657 } 658 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 659 &s->skcipher_tfm, 660 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 661 if (unlikely(rc)) { 662 printk(KERN_ERR "Internal error whilst attempting to get " 663 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 664 mount_crypt_stat->global_default_fn_cipher_name, rc); 665 goto out; 666 } 667 mutex_lock(s->tfm_mutex); 668 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm); 669 /* Plus one for the \0 separator between the random prefix 670 * and the plaintext filename */ 671 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 672 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 673 if ((s->block_aligned_filename_size % s->block_size) != 0) { 674 s->num_rand_bytes += (s->block_size 675 - (s->block_aligned_filename_size 676 % s->block_size)); 677 s->block_aligned_filename_size = (s->num_rand_bytes 678 + filename_size); 679 } 680 /* Octet 0: Tag 70 identifier 681 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 682 * and block-aligned encrypted filename size) 683 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 684 * Octet N2-N3: Cipher identifier (1 octet) 685 * Octets N3-N4: Block-aligned encrypted filename 686 * - Consists of a minimum number of random characters, a \0 687 * separator, and then the filename */ 688 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 689 + s->block_aligned_filename_size); 690 if (dest == NULL) { 691 (*packet_size) = s->max_packet_size; 692 goto out_unlock; 693 } 694 if (s->max_packet_size > (*remaining_bytes)) { 695 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 696 "[%zd] available\n", __func__, s->max_packet_size, 697 (*remaining_bytes)); 698 rc = -EINVAL; 699 goto out_unlock; 700 } 701 702 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 703 if (!s->skcipher_req) { 704 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 705 "skcipher_request_alloc for %s\n", __func__, 706 crypto_skcipher_driver_name(s->skcipher_tfm)); 707 rc = -ENOMEM; 708 goto out_unlock; 709 } 710 711 skcipher_request_set_callback(s->skcipher_req, 712 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 713 714 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 715 GFP_KERNEL); 716 if (!s->block_aligned_filename) { 717 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 718 "kzalloc [%zd] bytes\n", __func__, 719 s->block_aligned_filename_size); 720 rc = -ENOMEM; 721 goto out_unlock; 722 } 723 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 724 rc = ecryptfs_write_packet_length(&dest[s->i], 725 (ECRYPTFS_SIG_SIZE 726 + 1 /* Cipher code */ 727 + s->block_aligned_filename_size), 728 &s->packet_size_len); 729 if (rc) { 730 printk(KERN_ERR "%s: Error generating tag 70 packet " 731 "header; cannot generate packet length; rc = [%d]\n", 732 __func__, rc); 733 goto out_free_unlock; 734 } 735 s->i += s->packet_size_len; 736 ecryptfs_from_hex(&dest[s->i], 737 mount_crypt_stat->global_default_fnek_sig, 738 ECRYPTFS_SIG_SIZE); 739 s->i += ECRYPTFS_SIG_SIZE; 740 s->cipher_code = ecryptfs_code_for_cipher_string( 741 mount_crypt_stat->global_default_fn_cipher_name, 742 mount_crypt_stat->global_default_fn_cipher_key_bytes); 743 if (s->cipher_code == 0) { 744 printk(KERN_WARNING "%s: Unable to generate code for " 745 "cipher [%s] with key bytes [%zd]\n", __func__, 746 mount_crypt_stat->global_default_fn_cipher_name, 747 mount_crypt_stat->global_default_fn_cipher_key_bytes); 748 rc = -EINVAL; 749 goto out_free_unlock; 750 } 751 dest[s->i++] = s->cipher_code; 752 /* TODO: Support other key modules than passphrase for 753 * filename encryption */ 754 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 755 rc = -EOPNOTSUPP; 756 printk(KERN_INFO "%s: Filename encryption only supports " 757 "password tokens\n", __func__); 758 goto out_free_unlock; 759 } 760 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0); 761 if (IS_ERR(s->hash_tfm)) { 762 rc = PTR_ERR(s->hash_tfm); 763 printk(KERN_ERR "%s: Error attempting to " 764 "allocate hash crypto context; rc = [%d]\n", 765 __func__, rc); 766 goto out_free_unlock; 767 } 768 769 s->hash_desc = kmalloc(sizeof(*s->hash_desc) + 770 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL); 771 if (!s->hash_desc) { 772 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 773 "kmalloc [%zd] bytes\n", __func__, 774 sizeof(*s->hash_desc) + 775 crypto_shash_descsize(s->hash_tfm)); 776 rc = -ENOMEM; 777 goto out_release_free_unlock; 778 } 779 780 s->hash_desc->tfm = s->hash_tfm; 781 s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; 782 783 rc = crypto_shash_digest(s->hash_desc, 784 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 785 s->auth_tok->token.password.session_key_encryption_key_bytes, 786 s->hash); 787 if (rc) { 788 printk(KERN_ERR 789 "%s: Error computing crypto hash; rc = [%d]\n", 790 __func__, rc); 791 goto out_release_free_unlock; 792 } 793 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 794 s->block_aligned_filename[s->j] = 795 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 796 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 797 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 798 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash, 799 ECRYPTFS_TAG_70_DIGEST_SIZE, 800 s->tmp_hash); 801 if (rc) { 802 printk(KERN_ERR 803 "%s: Error computing crypto hash; " 804 "rc = [%d]\n", __func__, rc); 805 goto out_release_free_unlock; 806 } 807 memcpy(s->hash, s->tmp_hash, 808 ECRYPTFS_TAG_70_DIGEST_SIZE); 809 } 810 if (s->block_aligned_filename[s->j] == '\0') 811 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 812 } 813 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 814 filename_size); 815 rc = virt_to_scatterlist(s->block_aligned_filename, 816 s->block_aligned_filename_size, s->src_sg, 2); 817 if (rc < 1) { 818 printk(KERN_ERR "%s: Internal error whilst attempting to " 819 "convert filename memory to scatterlist; rc = [%d]. " 820 "block_aligned_filename_size = [%zd]\n", __func__, rc, 821 s->block_aligned_filename_size); 822 goto out_release_free_unlock; 823 } 824 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 825 s->dst_sg, 2); 826 if (rc < 1) { 827 printk(KERN_ERR "%s: Internal error whilst attempting to " 828 "convert encrypted filename memory to scatterlist; " 829 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 830 __func__, rc, s->block_aligned_filename_size); 831 goto out_release_free_unlock; 832 } 833 /* The characters in the first block effectively do the job 834 * of the IV here, so we just use 0's for the IV. Note the 835 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 836 * >= ECRYPTFS_MAX_IV_BYTES. */ 837 rc = crypto_skcipher_setkey( 838 s->skcipher_tfm, 839 s->auth_tok->token.password.session_key_encryption_key, 840 mount_crypt_stat->global_default_fn_cipher_key_bytes); 841 if (rc < 0) { 842 printk(KERN_ERR "%s: Error setting key for crypto context; " 843 "rc = [%d]. s->auth_tok->token.password.session_key_" 844 "encryption_key = [0x%p]; mount_crypt_stat->" 845 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 846 rc, 847 s->auth_tok->token.password.session_key_encryption_key, 848 mount_crypt_stat->global_default_fn_cipher_key_bytes); 849 goto out_release_free_unlock; 850 } 851 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 852 s->block_aligned_filename_size, s->iv); 853 rc = crypto_skcipher_encrypt(s->skcipher_req); 854 if (rc) { 855 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 856 "rc = [%d]\n", __func__, rc); 857 goto out_release_free_unlock; 858 } 859 s->i += s->block_aligned_filename_size; 860 (*packet_size) = s->i; 861 (*remaining_bytes) -= (*packet_size); 862 out_release_free_unlock: 863 crypto_free_shash(s->hash_tfm); 864 out_free_unlock: 865 kzfree(s->block_aligned_filename); 866 out_unlock: 867 mutex_unlock(s->tfm_mutex); 868 out: 869 if (auth_tok_key) { 870 up_write(&(auth_tok_key->sem)); 871 key_put(auth_tok_key); 872 } 873 skcipher_request_free(s->skcipher_req); 874 kzfree(s->hash_desc); 875 kfree(s); 876 return rc; 877 } 878 879 struct ecryptfs_parse_tag_70_packet_silly_stack { 880 u8 cipher_code; 881 size_t max_packet_size; 882 size_t packet_size_len; 883 size_t parsed_tag_70_packet_size; 884 size_t block_aligned_filename_size; 885 size_t block_size; 886 size_t i; 887 struct mutex *tfm_mutex; 888 char *decrypted_filename; 889 struct ecryptfs_auth_tok *auth_tok; 890 struct scatterlist src_sg[2]; 891 struct scatterlist dst_sg[2]; 892 struct crypto_skcipher *skcipher_tfm; 893 struct skcipher_request *skcipher_req; 894 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 895 char iv[ECRYPTFS_MAX_IV_BYTES]; 896 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; 897 }; 898 899 /** 900 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 901 * @filename: This function kmalloc's the memory for the filename 902 * @filename_size: This function sets this to the amount of memory 903 * kmalloc'd for the filename 904 * @packet_size: This function sets this to the the number of octets 905 * in the packet parsed 906 * @mount_crypt_stat: The mount-wide cryptographic context 907 * @data: The memory location containing the start of the tag 70 908 * packet 909 * @max_packet_size: The maximum legal size of the packet to be parsed 910 * from @data 911 * 912 * Returns zero on success; non-zero otherwise 913 */ 914 int 915 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 916 size_t *packet_size, 917 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 918 char *data, size_t max_packet_size) 919 { 920 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 921 struct key *auth_tok_key = NULL; 922 int rc = 0; 923 924 (*packet_size) = 0; 925 (*filename_size) = 0; 926 (*filename) = NULL; 927 s = kzalloc(sizeof(*s), GFP_KERNEL); 928 if (!s) { 929 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " 930 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); 931 return -ENOMEM; 932 } 933 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 934 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 935 "at least [%d]\n", __func__, max_packet_size, 936 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 937 rc = -EINVAL; 938 goto out; 939 } 940 /* Octet 0: Tag 70 identifier 941 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 942 * and block-aligned encrypted filename size) 943 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 944 * Octet N2-N3: Cipher identifier (1 octet) 945 * Octets N3-N4: Block-aligned encrypted filename 946 * - Consists of a minimum number of random numbers, a \0 947 * separator, and then the filename */ 948 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 949 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 950 "tag [0x%.2x]\n", __func__, 951 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 952 rc = -EINVAL; 953 goto out; 954 } 955 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 956 &s->parsed_tag_70_packet_size, 957 &s->packet_size_len); 958 if (rc) { 959 printk(KERN_WARNING "%s: Error parsing packet length; " 960 "rc = [%d]\n", __func__, rc); 961 goto out; 962 } 963 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 964 - ECRYPTFS_SIG_SIZE - 1); 965 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 966 > max_packet_size) { 967 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 968 "size is [%zd]\n", __func__, max_packet_size, 969 (1 + s->packet_size_len + 1 970 + s->block_aligned_filename_size)); 971 rc = -EINVAL; 972 goto out; 973 } 974 (*packet_size) += s->packet_size_len; 975 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 976 ECRYPTFS_SIG_SIZE); 977 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 978 (*packet_size) += ECRYPTFS_SIG_SIZE; 979 s->cipher_code = data[(*packet_size)++]; 980 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 981 if (rc) { 982 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 983 __func__, s->cipher_code); 984 goto out; 985 } 986 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 987 &s->auth_tok, mount_crypt_stat, 988 s->fnek_sig_hex); 989 if (rc) { 990 printk(KERN_ERR "%s: Error attempting to find auth tok for " 991 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 992 rc); 993 goto out; 994 } 995 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm, 996 &s->tfm_mutex, 997 s->cipher_string); 998 if (unlikely(rc)) { 999 printk(KERN_ERR "Internal error whilst attempting to get " 1000 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1001 s->cipher_string, rc); 1002 goto out; 1003 } 1004 mutex_lock(s->tfm_mutex); 1005 rc = virt_to_scatterlist(&data[(*packet_size)], 1006 s->block_aligned_filename_size, s->src_sg, 2); 1007 if (rc < 1) { 1008 printk(KERN_ERR "%s: Internal error whilst attempting to " 1009 "convert encrypted filename memory to scatterlist; " 1010 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1011 __func__, rc, s->block_aligned_filename_size); 1012 goto out_unlock; 1013 } 1014 (*packet_size) += s->block_aligned_filename_size; 1015 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 1016 GFP_KERNEL); 1017 if (!s->decrypted_filename) { 1018 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1019 "kmalloc [%zd] bytes\n", __func__, 1020 s->block_aligned_filename_size); 1021 rc = -ENOMEM; 1022 goto out_unlock; 1023 } 1024 rc = virt_to_scatterlist(s->decrypted_filename, 1025 s->block_aligned_filename_size, s->dst_sg, 2); 1026 if (rc < 1) { 1027 printk(KERN_ERR "%s: Internal error whilst attempting to " 1028 "convert decrypted filename memory to scatterlist; " 1029 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1030 __func__, rc, s->block_aligned_filename_size); 1031 goto out_free_unlock; 1032 } 1033 1034 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 1035 if (!s->skcipher_req) { 1036 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1037 "skcipher_request_alloc for %s\n", __func__, 1038 crypto_skcipher_driver_name(s->skcipher_tfm)); 1039 rc = -ENOMEM; 1040 goto out_free_unlock; 1041 } 1042 1043 skcipher_request_set_callback(s->skcipher_req, 1044 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 1045 1046 /* The characters in the first block effectively do the job of 1047 * the IV here, so we just use 0's for the IV. Note the 1048 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1049 * >= ECRYPTFS_MAX_IV_BYTES. */ 1050 /* TODO: Support other key modules than passphrase for 1051 * filename encryption */ 1052 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1053 rc = -EOPNOTSUPP; 1054 printk(KERN_INFO "%s: Filename encryption only supports " 1055 "password tokens\n", __func__); 1056 goto out_free_unlock; 1057 } 1058 rc = crypto_skcipher_setkey( 1059 s->skcipher_tfm, 1060 s->auth_tok->token.password.session_key_encryption_key, 1061 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1062 if (rc < 0) { 1063 printk(KERN_ERR "%s: Error setting key for crypto context; " 1064 "rc = [%d]. s->auth_tok->token.password.session_key_" 1065 "encryption_key = [0x%p]; mount_crypt_stat->" 1066 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1067 rc, 1068 s->auth_tok->token.password.session_key_encryption_key, 1069 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1070 goto out_free_unlock; 1071 } 1072 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 1073 s->block_aligned_filename_size, s->iv); 1074 rc = crypto_skcipher_decrypt(s->skcipher_req); 1075 if (rc) { 1076 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1077 "rc = [%d]\n", __func__, rc); 1078 goto out_free_unlock; 1079 } 1080 while (s->decrypted_filename[s->i] != '\0' 1081 && s->i < s->block_aligned_filename_size) 1082 s->i++; 1083 if (s->i == s->block_aligned_filename_size) { 1084 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1085 "find valid separator between random characters and " 1086 "the filename\n", __func__); 1087 rc = -EINVAL; 1088 goto out_free_unlock; 1089 } 1090 s->i++; 1091 (*filename_size) = (s->block_aligned_filename_size - s->i); 1092 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1093 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1094 "invalid\n", __func__, (*filename_size)); 1095 rc = -EINVAL; 1096 goto out_free_unlock; 1097 } 1098 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1099 if (!(*filename)) { 1100 printk(KERN_ERR "%s: Out of memory whilst attempting to " 1101 "kmalloc [%zd] bytes\n", __func__, 1102 ((*filename_size) + 1)); 1103 rc = -ENOMEM; 1104 goto out_free_unlock; 1105 } 1106 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1107 (*filename)[(*filename_size)] = '\0'; 1108 out_free_unlock: 1109 kfree(s->decrypted_filename); 1110 out_unlock: 1111 mutex_unlock(s->tfm_mutex); 1112 out: 1113 if (rc) { 1114 (*packet_size) = 0; 1115 (*filename_size) = 0; 1116 (*filename) = NULL; 1117 } 1118 if (auth_tok_key) { 1119 up_write(&(auth_tok_key->sem)); 1120 key_put(auth_tok_key); 1121 } 1122 skcipher_request_free(s->skcipher_req); 1123 kfree(s); 1124 return rc; 1125 } 1126 1127 static int 1128 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1129 { 1130 int rc = 0; 1131 1132 (*sig) = NULL; 1133 switch (auth_tok->token_type) { 1134 case ECRYPTFS_PASSWORD: 1135 (*sig) = auth_tok->token.password.signature; 1136 break; 1137 case ECRYPTFS_PRIVATE_KEY: 1138 (*sig) = auth_tok->token.private_key.signature; 1139 break; 1140 default: 1141 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1142 auth_tok->token_type); 1143 rc = -EINVAL; 1144 } 1145 return rc; 1146 } 1147 1148 /** 1149 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1150 * @auth_tok: The key authentication token used to decrypt the session key 1151 * @crypt_stat: The cryptographic context 1152 * 1153 * Returns zero on success; non-zero error otherwise. 1154 */ 1155 static int 1156 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1157 struct ecryptfs_crypt_stat *crypt_stat) 1158 { 1159 u8 cipher_code = 0; 1160 struct ecryptfs_msg_ctx *msg_ctx; 1161 struct ecryptfs_message *msg = NULL; 1162 char *auth_tok_sig; 1163 char *payload = NULL; 1164 size_t payload_len = 0; 1165 int rc; 1166 1167 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1168 if (rc) { 1169 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1170 auth_tok->token_type); 1171 goto out; 1172 } 1173 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1174 &payload, &payload_len); 1175 if (rc) { 1176 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1177 goto out; 1178 } 1179 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1180 if (rc) { 1181 ecryptfs_printk(KERN_ERR, "Error sending message to " 1182 "ecryptfsd: %d\n", rc); 1183 goto out; 1184 } 1185 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1186 if (rc) { 1187 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1188 "from the user space daemon\n"); 1189 rc = -EIO; 1190 goto out; 1191 } 1192 rc = parse_tag_65_packet(&(auth_tok->session_key), 1193 &cipher_code, msg); 1194 if (rc) { 1195 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1196 rc); 1197 goto out; 1198 } 1199 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1200 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1201 auth_tok->session_key.decrypted_key_size); 1202 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1203 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1204 if (rc) { 1205 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1206 cipher_code) 1207 goto out; 1208 } 1209 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1210 if (ecryptfs_verbosity > 0) { 1211 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1212 ecryptfs_dump_hex(crypt_stat->key, 1213 crypt_stat->key_size); 1214 } 1215 out: 1216 kfree(msg); 1217 kfree(payload); 1218 return rc; 1219 } 1220 1221 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1222 { 1223 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1224 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1225 1226 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1227 auth_tok_list_head, list) { 1228 list_del(&auth_tok_list_item->list); 1229 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1230 auth_tok_list_item); 1231 } 1232 } 1233 1234 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1235 1236 /** 1237 * parse_tag_1_packet 1238 * @crypt_stat: The cryptographic context to modify based on packet contents 1239 * @data: The raw bytes of the packet. 1240 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1241 * a new authentication token will be placed at the 1242 * end of this list for this packet. 1243 * @new_auth_tok: Pointer to a pointer to memory that this function 1244 * allocates; sets the memory address of the pointer to 1245 * NULL on error. This object is added to the 1246 * auth_tok_list. 1247 * @packet_size: This function writes the size of the parsed packet 1248 * into this memory location; zero on error. 1249 * @max_packet_size: The maximum allowable packet size 1250 * 1251 * Returns zero on success; non-zero on error. 1252 */ 1253 static int 1254 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1255 unsigned char *data, struct list_head *auth_tok_list, 1256 struct ecryptfs_auth_tok **new_auth_tok, 1257 size_t *packet_size, size_t max_packet_size) 1258 { 1259 size_t body_size; 1260 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1261 size_t length_size; 1262 int rc = 0; 1263 1264 (*packet_size) = 0; 1265 (*new_auth_tok) = NULL; 1266 /** 1267 * This format is inspired by OpenPGP; see RFC 2440 1268 * packet tag 1 1269 * 1270 * Tag 1 identifier (1 byte) 1271 * Max Tag 1 packet size (max 3 bytes) 1272 * Version (1 byte) 1273 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1274 * Cipher identifier (1 byte) 1275 * Encrypted key size (arbitrary) 1276 * 1277 * 12 bytes minimum packet size 1278 */ 1279 if (unlikely(max_packet_size < 12)) { 1280 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1281 rc = -EINVAL; 1282 goto out; 1283 } 1284 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1285 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1286 ECRYPTFS_TAG_1_PACKET_TYPE); 1287 rc = -EINVAL; 1288 goto out; 1289 } 1290 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1291 * at end of function upon failure */ 1292 auth_tok_list_item = 1293 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1294 GFP_KERNEL); 1295 if (!auth_tok_list_item) { 1296 printk(KERN_ERR "Unable to allocate memory\n"); 1297 rc = -ENOMEM; 1298 goto out; 1299 } 1300 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1301 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1302 &length_size); 1303 if (rc) { 1304 printk(KERN_WARNING "Error parsing packet length; " 1305 "rc = [%d]\n", rc); 1306 goto out_free; 1307 } 1308 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1309 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1310 rc = -EINVAL; 1311 goto out_free; 1312 } 1313 (*packet_size) += length_size; 1314 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1315 printk(KERN_WARNING "Packet size exceeds max\n"); 1316 rc = -EINVAL; 1317 goto out_free; 1318 } 1319 if (unlikely(data[(*packet_size)++] != 0x03)) { 1320 printk(KERN_WARNING "Unknown version number [%d]\n", 1321 data[(*packet_size) - 1]); 1322 rc = -EINVAL; 1323 goto out_free; 1324 } 1325 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1326 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1327 *packet_size += ECRYPTFS_SIG_SIZE; 1328 /* This byte is skipped because the kernel does not need to 1329 * know which public key encryption algorithm was used */ 1330 (*packet_size)++; 1331 (*new_auth_tok)->session_key.encrypted_key_size = 1332 body_size - (ECRYPTFS_SIG_SIZE + 2); 1333 if ((*new_auth_tok)->session_key.encrypted_key_size 1334 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1335 printk(KERN_WARNING "Tag 1 packet contains key larger " 1336 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); 1337 rc = -EINVAL; 1338 goto out; 1339 } 1340 memcpy((*new_auth_tok)->session_key.encrypted_key, 1341 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1342 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1343 (*new_auth_tok)->session_key.flags &= 1344 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1345 (*new_auth_tok)->session_key.flags |= 1346 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1347 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1348 (*new_auth_tok)->flags = 0; 1349 (*new_auth_tok)->session_key.flags &= 1350 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1351 (*new_auth_tok)->session_key.flags &= 1352 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1353 list_add(&auth_tok_list_item->list, auth_tok_list); 1354 goto out; 1355 out_free: 1356 (*new_auth_tok) = NULL; 1357 memset(auth_tok_list_item, 0, 1358 sizeof(struct ecryptfs_auth_tok_list_item)); 1359 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1360 auth_tok_list_item); 1361 out: 1362 if (rc) 1363 (*packet_size) = 0; 1364 return rc; 1365 } 1366 1367 /** 1368 * parse_tag_3_packet 1369 * @crypt_stat: The cryptographic context to modify based on packet 1370 * contents. 1371 * @data: The raw bytes of the packet. 1372 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1373 * a new authentication token will be placed at the end 1374 * of this list for this packet. 1375 * @new_auth_tok: Pointer to a pointer to memory that this function 1376 * allocates; sets the memory address of the pointer to 1377 * NULL on error. This object is added to the 1378 * auth_tok_list. 1379 * @packet_size: This function writes the size of the parsed packet 1380 * into this memory location; zero on error. 1381 * @max_packet_size: maximum number of bytes to parse 1382 * 1383 * Returns zero on success; non-zero on error. 1384 */ 1385 static int 1386 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1387 unsigned char *data, struct list_head *auth_tok_list, 1388 struct ecryptfs_auth_tok **new_auth_tok, 1389 size_t *packet_size, size_t max_packet_size) 1390 { 1391 size_t body_size; 1392 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1393 size_t length_size; 1394 int rc = 0; 1395 1396 (*packet_size) = 0; 1397 (*new_auth_tok) = NULL; 1398 /** 1399 *This format is inspired by OpenPGP; see RFC 2440 1400 * packet tag 3 1401 * 1402 * Tag 3 identifier (1 byte) 1403 * Max Tag 3 packet size (max 3 bytes) 1404 * Version (1 byte) 1405 * Cipher code (1 byte) 1406 * S2K specifier (1 byte) 1407 * Hash identifier (1 byte) 1408 * Salt (ECRYPTFS_SALT_SIZE) 1409 * Hash iterations (1 byte) 1410 * Encrypted key (arbitrary) 1411 * 1412 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1413 */ 1414 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1415 printk(KERN_ERR "Max packet size too large\n"); 1416 rc = -EINVAL; 1417 goto out; 1418 } 1419 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1420 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1421 ECRYPTFS_TAG_3_PACKET_TYPE); 1422 rc = -EINVAL; 1423 goto out; 1424 } 1425 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1426 * at end of function upon failure */ 1427 auth_tok_list_item = 1428 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1429 if (!auth_tok_list_item) { 1430 printk(KERN_ERR "Unable to allocate memory\n"); 1431 rc = -ENOMEM; 1432 goto out; 1433 } 1434 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1435 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1436 &length_size); 1437 if (rc) { 1438 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1439 rc); 1440 goto out_free; 1441 } 1442 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1443 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1444 rc = -EINVAL; 1445 goto out_free; 1446 } 1447 (*packet_size) += length_size; 1448 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1449 printk(KERN_ERR "Packet size exceeds max\n"); 1450 rc = -EINVAL; 1451 goto out_free; 1452 } 1453 (*new_auth_tok)->session_key.encrypted_key_size = 1454 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1455 if ((*new_auth_tok)->session_key.encrypted_key_size 1456 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1457 printk(KERN_WARNING "Tag 3 packet contains key larger " 1458 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1459 rc = -EINVAL; 1460 goto out_free; 1461 } 1462 if (unlikely(data[(*packet_size)++] != 0x04)) { 1463 printk(KERN_WARNING "Unknown version number [%d]\n", 1464 data[(*packet_size) - 1]); 1465 rc = -EINVAL; 1466 goto out_free; 1467 } 1468 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1469 (u16)data[(*packet_size)]); 1470 if (rc) 1471 goto out_free; 1472 /* A little extra work to differentiate among the AES key 1473 * sizes; see RFC2440 */ 1474 switch(data[(*packet_size)++]) { 1475 case RFC2440_CIPHER_AES_192: 1476 crypt_stat->key_size = 24; 1477 break; 1478 default: 1479 crypt_stat->key_size = 1480 (*new_auth_tok)->session_key.encrypted_key_size; 1481 } 1482 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1483 if (rc) 1484 goto out_free; 1485 if (unlikely(data[(*packet_size)++] != 0x03)) { 1486 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1487 rc = -ENOSYS; 1488 goto out_free; 1489 } 1490 /* TODO: finish the hash mapping */ 1491 switch (data[(*packet_size)++]) { 1492 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1493 /* Choose MD5 */ 1494 memcpy((*new_auth_tok)->token.password.salt, 1495 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1496 (*packet_size) += ECRYPTFS_SALT_SIZE; 1497 /* This conversion was taken straight from RFC2440 */ 1498 (*new_auth_tok)->token.password.hash_iterations = 1499 ((u32) 16 + (data[(*packet_size)] & 15)) 1500 << ((data[(*packet_size)] >> 4) + 6); 1501 (*packet_size)++; 1502 /* Friendly reminder: 1503 * (*new_auth_tok)->session_key.encrypted_key_size = 1504 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1505 memcpy((*new_auth_tok)->session_key.encrypted_key, 1506 &data[(*packet_size)], 1507 (*new_auth_tok)->session_key.encrypted_key_size); 1508 (*packet_size) += 1509 (*new_auth_tok)->session_key.encrypted_key_size; 1510 (*new_auth_tok)->session_key.flags &= 1511 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1512 (*new_auth_tok)->session_key.flags |= 1513 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1514 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1515 break; 1516 default: 1517 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1518 "[%d]\n", data[(*packet_size) - 1]); 1519 rc = -ENOSYS; 1520 goto out_free; 1521 } 1522 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1523 /* TODO: Parametarize; we might actually want userspace to 1524 * decrypt the session key. */ 1525 (*new_auth_tok)->session_key.flags &= 1526 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1527 (*new_auth_tok)->session_key.flags &= 1528 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1529 list_add(&auth_tok_list_item->list, auth_tok_list); 1530 goto out; 1531 out_free: 1532 (*new_auth_tok) = NULL; 1533 memset(auth_tok_list_item, 0, 1534 sizeof(struct ecryptfs_auth_tok_list_item)); 1535 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1536 auth_tok_list_item); 1537 out: 1538 if (rc) 1539 (*packet_size) = 0; 1540 return rc; 1541 } 1542 1543 /** 1544 * parse_tag_11_packet 1545 * @data: The raw bytes of the packet 1546 * @contents: This function writes the data contents of the literal 1547 * packet into this memory location 1548 * @max_contents_bytes: The maximum number of bytes that this function 1549 * is allowed to write into contents 1550 * @tag_11_contents_size: This function writes the size of the parsed 1551 * contents into this memory location; zero on 1552 * error 1553 * @packet_size: This function writes the size of the parsed packet 1554 * into this memory location; zero on error 1555 * @max_packet_size: maximum number of bytes to parse 1556 * 1557 * Returns zero on success; non-zero on error. 1558 */ 1559 static int 1560 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1561 size_t max_contents_bytes, size_t *tag_11_contents_size, 1562 size_t *packet_size, size_t max_packet_size) 1563 { 1564 size_t body_size; 1565 size_t length_size; 1566 int rc = 0; 1567 1568 (*packet_size) = 0; 1569 (*tag_11_contents_size) = 0; 1570 /* This format is inspired by OpenPGP; see RFC 2440 1571 * packet tag 11 1572 * 1573 * Tag 11 identifier (1 byte) 1574 * Max Tag 11 packet size (max 3 bytes) 1575 * Binary format specifier (1 byte) 1576 * Filename length (1 byte) 1577 * Filename ("_CONSOLE") (8 bytes) 1578 * Modification date (4 bytes) 1579 * Literal data (arbitrary) 1580 * 1581 * We need at least 16 bytes of data for the packet to even be 1582 * valid. 1583 */ 1584 if (max_packet_size < 16) { 1585 printk(KERN_ERR "Maximum packet size too small\n"); 1586 rc = -EINVAL; 1587 goto out; 1588 } 1589 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1590 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1591 rc = -EINVAL; 1592 goto out; 1593 } 1594 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1595 &length_size); 1596 if (rc) { 1597 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1598 goto out; 1599 } 1600 if (body_size < 14) { 1601 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1602 rc = -EINVAL; 1603 goto out; 1604 } 1605 (*packet_size) += length_size; 1606 (*tag_11_contents_size) = (body_size - 14); 1607 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1608 printk(KERN_ERR "Packet size exceeds max\n"); 1609 rc = -EINVAL; 1610 goto out; 1611 } 1612 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1613 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1614 "expected size\n"); 1615 rc = -EINVAL; 1616 goto out; 1617 } 1618 if (data[(*packet_size)++] != 0x62) { 1619 printk(KERN_WARNING "Unrecognizable packet\n"); 1620 rc = -EINVAL; 1621 goto out; 1622 } 1623 if (data[(*packet_size)++] != 0x08) { 1624 printk(KERN_WARNING "Unrecognizable packet\n"); 1625 rc = -EINVAL; 1626 goto out; 1627 } 1628 (*packet_size) += 12; /* Ignore filename and modification date */ 1629 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1630 (*packet_size) += (*tag_11_contents_size); 1631 out: 1632 if (rc) { 1633 (*packet_size) = 0; 1634 (*tag_11_contents_size) = 0; 1635 } 1636 return rc; 1637 } 1638 1639 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1640 struct ecryptfs_auth_tok **auth_tok, 1641 char *sig) 1642 { 1643 int rc = 0; 1644 1645 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1646 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1647 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1648 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1649 printk(KERN_ERR "Could not find key with description: [%s]\n", 1650 sig); 1651 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1652 (*auth_tok_key) = NULL; 1653 goto out; 1654 } 1655 } 1656 down_write(&(*auth_tok_key)->sem); 1657 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1658 if (rc) { 1659 up_write(&(*auth_tok_key)->sem); 1660 key_put(*auth_tok_key); 1661 (*auth_tok_key) = NULL; 1662 goto out; 1663 } 1664 out: 1665 return rc; 1666 } 1667 1668 /** 1669 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1670 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1671 * @crypt_stat: The cryptographic context 1672 * 1673 * Returns zero on success; non-zero error otherwise 1674 */ 1675 static int 1676 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1677 struct ecryptfs_crypt_stat *crypt_stat) 1678 { 1679 struct scatterlist dst_sg[2]; 1680 struct scatterlist src_sg[2]; 1681 struct mutex *tfm_mutex; 1682 struct crypto_skcipher *tfm; 1683 struct skcipher_request *req = NULL; 1684 int rc = 0; 1685 1686 if (unlikely(ecryptfs_verbosity > 0)) { 1687 ecryptfs_printk( 1688 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1689 auth_tok->token.password.session_key_encryption_key_bytes); 1690 ecryptfs_dump_hex( 1691 auth_tok->token.password.session_key_encryption_key, 1692 auth_tok->token.password.session_key_encryption_key_bytes); 1693 } 1694 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 1695 crypt_stat->cipher); 1696 if (unlikely(rc)) { 1697 printk(KERN_ERR "Internal error whilst attempting to get " 1698 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1699 crypt_stat->cipher, rc); 1700 goto out; 1701 } 1702 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1703 auth_tok->session_key.encrypted_key_size, 1704 src_sg, 2); 1705 if (rc < 1 || rc > 2) { 1706 printk(KERN_ERR "Internal error whilst attempting to convert " 1707 "auth_tok->session_key.encrypted_key to scatterlist; " 1708 "expected rc = 1; got rc = [%d]. " 1709 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1710 auth_tok->session_key.encrypted_key_size); 1711 goto out; 1712 } 1713 auth_tok->session_key.decrypted_key_size = 1714 auth_tok->session_key.encrypted_key_size; 1715 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1716 auth_tok->session_key.decrypted_key_size, 1717 dst_sg, 2); 1718 if (rc < 1 || rc > 2) { 1719 printk(KERN_ERR "Internal error whilst attempting to convert " 1720 "auth_tok->session_key.decrypted_key to scatterlist; " 1721 "expected rc = 1; got rc = [%d]\n", rc); 1722 goto out; 1723 } 1724 mutex_lock(tfm_mutex); 1725 req = skcipher_request_alloc(tfm, GFP_KERNEL); 1726 if (!req) { 1727 mutex_unlock(tfm_mutex); 1728 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1729 "skcipher_request_alloc for %s\n", __func__, 1730 crypto_skcipher_driver_name(tfm)); 1731 rc = -ENOMEM; 1732 goto out; 1733 } 1734 1735 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 1736 NULL, NULL); 1737 rc = crypto_skcipher_setkey( 1738 tfm, auth_tok->token.password.session_key_encryption_key, 1739 crypt_stat->key_size); 1740 if (unlikely(rc < 0)) { 1741 mutex_unlock(tfm_mutex); 1742 printk(KERN_ERR "Error setting key for crypto context\n"); 1743 rc = -EINVAL; 1744 goto out; 1745 } 1746 skcipher_request_set_crypt(req, src_sg, dst_sg, 1747 auth_tok->session_key.encrypted_key_size, 1748 NULL); 1749 rc = crypto_skcipher_decrypt(req); 1750 mutex_unlock(tfm_mutex); 1751 if (unlikely(rc)) { 1752 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1753 goto out; 1754 } 1755 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1756 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1757 auth_tok->session_key.decrypted_key_size); 1758 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1759 if (unlikely(ecryptfs_verbosity > 0)) { 1760 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1761 crypt_stat->key_size); 1762 ecryptfs_dump_hex(crypt_stat->key, 1763 crypt_stat->key_size); 1764 } 1765 out: 1766 skcipher_request_free(req); 1767 return rc; 1768 } 1769 1770 /** 1771 * ecryptfs_parse_packet_set 1772 * @crypt_stat: The cryptographic context 1773 * @src: Virtual address of region of memory containing the packets 1774 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1775 * 1776 * Get crypt_stat to have the file's session key if the requisite key 1777 * is available to decrypt the session key. 1778 * 1779 * Returns Zero if a valid authentication token was retrieved and 1780 * processed; negative value for file not encrypted or for error 1781 * conditions. 1782 */ 1783 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1784 unsigned char *src, 1785 struct dentry *ecryptfs_dentry) 1786 { 1787 size_t i = 0; 1788 size_t found_auth_tok; 1789 size_t next_packet_is_auth_tok_packet; 1790 struct list_head auth_tok_list; 1791 struct ecryptfs_auth_tok *matching_auth_tok; 1792 struct ecryptfs_auth_tok *candidate_auth_tok; 1793 char *candidate_auth_tok_sig; 1794 size_t packet_size; 1795 struct ecryptfs_auth_tok *new_auth_tok; 1796 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1797 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1798 size_t tag_11_contents_size; 1799 size_t tag_11_packet_size; 1800 struct key *auth_tok_key = NULL; 1801 int rc = 0; 1802 1803 INIT_LIST_HEAD(&auth_tok_list); 1804 /* Parse the header to find as many packets as we can; these will be 1805 * added the our &auth_tok_list */ 1806 next_packet_is_auth_tok_packet = 1; 1807 while (next_packet_is_auth_tok_packet) { 1808 size_t max_packet_size = ((PAGE_SIZE - 8) - i); 1809 1810 switch (src[i]) { 1811 case ECRYPTFS_TAG_3_PACKET_TYPE: 1812 rc = parse_tag_3_packet(crypt_stat, 1813 (unsigned char *)&src[i], 1814 &auth_tok_list, &new_auth_tok, 1815 &packet_size, max_packet_size); 1816 if (rc) { 1817 ecryptfs_printk(KERN_ERR, "Error parsing " 1818 "tag 3 packet\n"); 1819 rc = -EIO; 1820 goto out_wipe_list; 1821 } 1822 i += packet_size; 1823 rc = parse_tag_11_packet((unsigned char *)&src[i], 1824 sig_tmp_space, 1825 ECRYPTFS_SIG_SIZE, 1826 &tag_11_contents_size, 1827 &tag_11_packet_size, 1828 max_packet_size); 1829 if (rc) { 1830 ecryptfs_printk(KERN_ERR, "No valid " 1831 "(ecryptfs-specific) literal " 1832 "packet containing " 1833 "authentication token " 1834 "signature found after " 1835 "tag 3 packet\n"); 1836 rc = -EIO; 1837 goto out_wipe_list; 1838 } 1839 i += tag_11_packet_size; 1840 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1841 ecryptfs_printk(KERN_ERR, "Expected " 1842 "signature of size [%d]; " 1843 "read size [%zd]\n", 1844 ECRYPTFS_SIG_SIZE, 1845 tag_11_contents_size); 1846 rc = -EIO; 1847 goto out_wipe_list; 1848 } 1849 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1850 sig_tmp_space, tag_11_contents_size); 1851 new_auth_tok->token.password.signature[ 1852 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1853 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1854 break; 1855 case ECRYPTFS_TAG_1_PACKET_TYPE: 1856 rc = parse_tag_1_packet(crypt_stat, 1857 (unsigned char *)&src[i], 1858 &auth_tok_list, &new_auth_tok, 1859 &packet_size, max_packet_size); 1860 if (rc) { 1861 ecryptfs_printk(KERN_ERR, "Error parsing " 1862 "tag 1 packet\n"); 1863 rc = -EIO; 1864 goto out_wipe_list; 1865 } 1866 i += packet_size; 1867 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1868 break; 1869 case ECRYPTFS_TAG_11_PACKET_TYPE: 1870 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1871 "(Tag 11 not allowed by itself)\n"); 1872 rc = -EIO; 1873 goto out_wipe_list; 1874 default: 1875 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1876 "of the file header; hex value of " 1877 "character is [0x%.2x]\n", i, src[i]); 1878 next_packet_is_auth_tok_packet = 0; 1879 } 1880 } 1881 if (list_empty(&auth_tok_list)) { 1882 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1883 "eCryptfs file; this is not supported in this version " 1884 "of the eCryptfs kernel module\n"); 1885 rc = -EINVAL; 1886 goto out; 1887 } 1888 /* auth_tok_list contains the set of authentication tokens 1889 * parsed from the metadata. We need to find a matching 1890 * authentication token that has the secret component(s) 1891 * necessary to decrypt the EFEK in the auth_tok parsed from 1892 * the metadata. There may be several potential matches, but 1893 * just one will be sufficient to decrypt to get the FEK. */ 1894 find_next_matching_auth_tok: 1895 found_auth_tok = 0; 1896 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1897 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1898 if (unlikely(ecryptfs_verbosity > 0)) { 1899 ecryptfs_printk(KERN_DEBUG, 1900 "Considering cadidate auth tok:\n"); 1901 ecryptfs_dump_auth_tok(candidate_auth_tok); 1902 } 1903 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1904 candidate_auth_tok); 1905 if (rc) { 1906 printk(KERN_ERR 1907 "Unrecognized candidate auth tok type: [%d]\n", 1908 candidate_auth_tok->token_type); 1909 rc = -EINVAL; 1910 goto out_wipe_list; 1911 } 1912 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1913 &matching_auth_tok, 1914 crypt_stat->mount_crypt_stat, 1915 candidate_auth_tok_sig); 1916 if (!rc) { 1917 found_auth_tok = 1; 1918 goto found_matching_auth_tok; 1919 } 1920 } 1921 if (!found_auth_tok) { 1922 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1923 "authentication token\n"); 1924 rc = -EIO; 1925 goto out_wipe_list; 1926 } 1927 found_matching_auth_tok: 1928 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1929 memcpy(&(candidate_auth_tok->token.private_key), 1930 &(matching_auth_tok->token.private_key), 1931 sizeof(struct ecryptfs_private_key)); 1932 up_write(&(auth_tok_key->sem)); 1933 key_put(auth_tok_key); 1934 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1935 crypt_stat); 1936 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1937 memcpy(&(candidate_auth_tok->token.password), 1938 &(matching_auth_tok->token.password), 1939 sizeof(struct ecryptfs_password)); 1940 up_write(&(auth_tok_key->sem)); 1941 key_put(auth_tok_key); 1942 rc = decrypt_passphrase_encrypted_session_key( 1943 candidate_auth_tok, crypt_stat); 1944 } else { 1945 up_write(&(auth_tok_key->sem)); 1946 key_put(auth_tok_key); 1947 rc = -EINVAL; 1948 } 1949 if (rc) { 1950 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1951 1952 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1953 "session key for authentication token with sig " 1954 "[%.*s]; rc = [%d]. Removing auth tok " 1955 "candidate from the list and searching for " 1956 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1957 candidate_auth_tok_sig, rc); 1958 list_for_each_entry_safe(auth_tok_list_item, 1959 auth_tok_list_item_tmp, 1960 &auth_tok_list, list) { 1961 if (candidate_auth_tok 1962 == &auth_tok_list_item->auth_tok) { 1963 list_del(&auth_tok_list_item->list); 1964 kmem_cache_free( 1965 ecryptfs_auth_tok_list_item_cache, 1966 auth_tok_list_item); 1967 goto find_next_matching_auth_tok; 1968 } 1969 } 1970 BUG(); 1971 } 1972 rc = ecryptfs_compute_root_iv(crypt_stat); 1973 if (rc) { 1974 ecryptfs_printk(KERN_ERR, "Error computing " 1975 "the root IV\n"); 1976 goto out_wipe_list; 1977 } 1978 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1979 if (rc) { 1980 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1981 "context for cipher [%s]; rc = [%d]\n", 1982 crypt_stat->cipher, rc); 1983 } 1984 out_wipe_list: 1985 wipe_auth_tok_list(&auth_tok_list); 1986 out: 1987 return rc; 1988 } 1989 1990 static int 1991 pki_encrypt_session_key(struct key *auth_tok_key, 1992 struct ecryptfs_auth_tok *auth_tok, 1993 struct ecryptfs_crypt_stat *crypt_stat, 1994 struct ecryptfs_key_record *key_rec) 1995 { 1996 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1997 char *payload = NULL; 1998 size_t payload_len = 0; 1999 struct ecryptfs_message *msg; 2000 int rc; 2001 2002 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 2003 ecryptfs_code_for_cipher_string( 2004 crypt_stat->cipher, 2005 crypt_stat->key_size), 2006 crypt_stat, &payload, &payload_len); 2007 up_write(&(auth_tok_key->sem)); 2008 key_put(auth_tok_key); 2009 if (rc) { 2010 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 2011 goto out; 2012 } 2013 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 2014 if (rc) { 2015 ecryptfs_printk(KERN_ERR, "Error sending message to " 2016 "ecryptfsd: %d\n", rc); 2017 goto out; 2018 } 2019 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 2020 if (rc) { 2021 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 2022 "from the user space daemon\n"); 2023 rc = -EIO; 2024 goto out; 2025 } 2026 rc = parse_tag_67_packet(key_rec, msg); 2027 if (rc) 2028 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2029 kfree(msg); 2030 out: 2031 kfree(payload); 2032 return rc; 2033 } 2034 /** 2035 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2036 * @dest: Buffer into which to write the packet 2037 * @remaining_bytes: Maximum number of bytes that can be writtn 2038 * @auth_tok_key: The authentication token key to unlock and put when done with 2039 * @auth_tok 2040 * @auth_tok: The authentication token used for generating the tag 1 packet 2041 * @crypt_stat: The cryptographic context 2042 * @key_rec: The key record struct for the tag 1 packet 2043 * @packet_size: This function will write the number of bytes that end 2044 * up constituting the packet; set to zero on error 2045 * 2046 * Returns zero on success; non-zero on error. 2047 */ 2048 static int 2049 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2050 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2051 struct ecryptfs_crypt_stat *crypt_stat, 2052 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2053 { 2054 size_t i; 2055 size_t encrypted_session_key_valid = 0; 2056 size_t packet_size_length; 2057 size_t max_packet_size; 2058 int rc = 0; 2059 2060 (*packet_size) = 0; 2061 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2062 ECRYPTFS_SIG_SIZE); 2063 encrypted_session_key_valid = 0; 2064 for (i = 0; i < crypt_stat->key_size; i++) 2065 encrypted_session_key_valid |= 2066 auth_tok->session_key.encrypted_key[i]; 2067 if (encrypted_session_key_valid) { 2068 memcpy(key_rec->enc_key, 2069 auth_tok->session_key.encrypted_key, 2070 auth_tok->session_key.encrypted_key_size); 2071 up_write(&(auth_tok_key->sem)); 2072 key_put(auth_tok_key); 2073 goto encrypted_session_key_set; 2074 } 2075 if (auth_tok->session_key.encrypted_key_size == 0) 2076 auth_tok->session_key.encrypted_key_size = 2077 auth_tok->token.private_key.key_size; 2078 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2079 key_rec); 2080 if (rc) { 2081 printk(KERN_ERR "Failed to encrypt session key via a key " 2082 "module; rc = [%d]\n", rc); 2083 goto out; 2084 } 2085 if (ecryptfs_verbosity > 0) { 2086 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2087 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2088 } 2089 encrypted_session_key_set: 2090 /* This format is inspired by OpenPGP; see RFC 2440 2091 * packet tag 1 */ 2092 max_packet_size = (1 /* Tag 1 identifier */ 2093 + 3 /* Max Tag 1 packet size */ 2094 + 1 /* Version */ 2095 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2096 + 1 /* Cipher identifier */ 2097 + key_rec->enc_key_size); /* Encrypted key size */ 2098 if (max_packet_size > (*remaining_bytes)) { 2099 printk(KERN_ERR "Packet length larger than maximum allowable; " 2100 "need up to [%td] bytes, but there are only [%td] " 2101 "available\n", max_packet_size, (*remaining_bytes)); 2102 rc = -EINVAL; 2103 goto out; 2104 } 2105 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2106 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2107 (max_packet_size - 4), 2108 &packet_size_length); 2109 if (rc) { 2110 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2111 "header; cannot generate packet length\n"); 2112 goto out; 2113 } 2114 (*packet_size) += packet_size_length; 2115 dest[(*packet_size)++] = 0x03; /* version 3 */ 2116 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2117 (*packet_size) += ECRYPTFS_SIG_SIZE; 2118 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2119 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2120 key_rec->enc_key_size); 2121 (*packet_size) += key_rec->enc_key_size; 2122 out: 2123 if (rc) 2124 (*packet_size) = 0; 2125 else 2126 (*remaining_bytes) -= (*packet_size); 2127 return rc; 2128 } 2129 2130 /** 2131 * write_tag_11_packet 2132 * @dest: Target into which Tag 11 packet is to be written 2133 * @remaining_bytes: Maximum packet length 2134 * @contents: Byte array of contents to copy in 2135 * @contents_length: Number of bytes in contents 2136 * @packet_length: Length of the Tag 11 packet written; zero on error 2137 * 2138 * Returns zero on success; non-zero on error. 2139 */ 2140 static int 2141 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2142 size_t contents_length, size_t *packet_length) 2143 { 2144 size_t packet_size_length; 2145 size_t max_packet_size; 2146 int rc = 0; 2147 2148 (*packet_length) = 0; 2149 /* This format is inspired by OpenPGP; see RFC 2440 2150 * packet tag 11 */ 2151 max_packet_size = (1 /* Tag 11 identifier */ 2152 + 3 /* Max Tag 11 packet size */ 2153 + 1 /* Binary format specifier */ 2154 + 1 /* Filename length */ 2155 + 8 /* Filename ("_CONSOLE") */ 2156 + 4 /* Modification date */ 2157 + contents_length); /* Literal data */ 2158 if (max_packet_size > (*remaining_bytes)) { 2159 printk(KERN_ERR "Packet length larger than maximum allowable; " 2160 "need up to [%td] bytes, but there are only [%td] " 2161 "available\n", max_packet_size, (*remaining_bytes)); 2162 rc = -EINVAL; 2163 goto out; 2164 } 2165 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2166 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2167 (max_packet_size - 4), 2168 &packet_size_length); 2169 if (rc) { 2170 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2171 "generate packet length. rc = [%d]\n", rc); 2172 goto out; 2173 } 2174 (*packet_length) += packet_size_length; 2175 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2176 dest[(*packet_length)++] = 8; 2177 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2178 (*packet_length) += 8; 2179 memset(&dest[(*packet_length)], 0x00, 4); 2180 (*packet_length) += 4; 2181 memcpy(&dest[(*packet_length)], contents, contents_length); 2182 (*packet_length) += contents_length; 2183 out: 2184 if (rc) 2185 (*packet_length) = 0; 2186 else 2187 (*remaining_bytes) -= (*packet_length); 2188 return rc; 2189 } 2190 2191 /** 2192 * write_tag_3_packet 2193 * @dest: Buffer into which to write the packet 2194 * @remaining_bytes: Maximum number of bytes that can be written 2195 * @auth_tok: Authentication token 2196 * @crypt_stat: The cryptographic context 2197 * @key_rec: encrypted key 2198 * @packet_size: This function will write the number of bytes that end 2199 * up constituting the packet; set to zero on error 2200 * 2201 * Returns zero on success; non-zero on error. 2202 */ 2203 static int 2204 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2205 struct ecryptfs_auth_tok *auth_tok, 2206 struct ecryptfs_crypt_stat *crypt_stat, 2207 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2208 { 2209 size_t i; 2210 size_t encrypted_session_key_valid = 0; 2211 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2212 struct scatterlist dst_sg[2]; 2213 struct scatterlist src_sg[2]; 2214 struct mutex *tfm_mutex = NULL; 2215 u8 cipher_code; 2216 size_t packet_size_length; 2217 size_t max_packet_size; 2218 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2219 crypt_stat->mount_crypt_stat; 2220 struct crypto_skcipher *tfm; 2221 struct skcipher_request *req; 2222 int rc = 0; 2223 2224 (*packet_size) = 0; 2225 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2226 ECRYPTFS_SIG_SIZE); 2227 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 2228 crypt_stat->cipher); 2229 if (unlikely(rc)) { 2230 printk(KERN_ERR "Internal error whilst attempting to get " 2231 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2232 crypt_stat->cipher, rc); 2233 goto out; 2234 } 2235 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2236 printk(KERN_WARNING "No key size specified at mount; " 2237 "defaulting to [%d]\n", 2238 crypto_skcipher_default_keysize(tfm)); 2239 mount_crypt_stat->global_default_cipher_key_size = 2240 crypto_skcipher_default_keysize(tfm); 2241 } 2242 if (crypt_stat->key_size == 0) 2243 crypt_stat->key_size = 2244 mount_crypt_stat->global_default_cipher_key_size; 2245 if (auth_tok->session_key.encrypted_key_size == 0) 2246 auth_tok->session_key.encrypted_key_size = 2247 crypt_stat->key_size; 2248 if (crypt_stat->key_size == 24 2249 && strcmp("aes", crypt_stat->cipher) == 0) { 2250 memset((crypt_stat->key + 24), 0, 8); 2251 auth_tok->session_key.encrypted_key_size = 32; 2252 } else 2253 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2254 key_rec->enc_key_size = 2255 auth_tok->session_key.encrypted_key_size; 2256 encrypted_session_key_valid = 0; 2257 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2258 encrypted_session_key_valid |= 2259 auth_tok->session_key.encrypted_key[i]; 2260 if (encrypted_session_key_valid) { 2261 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2262 "using auth_tok->session_key.encrypted_key, " 2263 "where key_rec->enc_key_size = [%zd]\n", 2264 key_rec->enc_key_size); 2265 memcpy(key_rec->enc_key, 2266 auth_tok->session_key.encrypted_key, 2267 key_rec->enc_key_size); 2268 goto encrypted_session_key_set; 2269 } 2270 if (auth_tok->token.password.flags & 2271 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2272 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2273 "session key encryption key of size [%d]\n", 2274 auth_tok->token.password. 2275 session_key_encryption_key_bytes); 2276 memcpy(session_key_encryption_key, 2277 auth_tok->token.password.session_key_encryption_key, 2278 crypt_stat->key_size); 2279 ecryptfs_printk(KERN_DEBUG, 2280 "Cached session key encryption key:\n"); 2281 if (ecryptfs_verbosity > 0) 2282 ecryptfs_dump_hex(session_key_encryption_key, 16); 2283 } 2284 if (unlikely(ecryptfs_verbosity > 0)) { 2285 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2286 ecryptfs_dump_hex(session_key_encryption_key, 16); 2287 } 2288 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2289 src_sg, 2); 2290 if (rc < 1 || rc > 2) { 2291 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2292 "for crypt_stat session key; expected rc = 1; " 2293 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2294 rc, key_rec->enc_key_size); 2295 rc = -ENOMEM; 2296 goto out; 2297 } 2298 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2299 dst_sg, 2); 2300 if (rc < 1 || rc > 2) { 2301 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2302 "for crypt_stat encrypted session key; " 2303 "expected rc = 1; got rc = [%d]. " 2304 "key_rec->enc_key_size = [%zd]\n", rc, 2305 key_rec->enc_key_size); 2306 rc = -ENOMEM; 2307 goto out; 2308 } 2309 mutex_lock(tfm_mutex); 2310 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key, 2311 crypt_stat->key_size); 2312 if (rc < 0) { 2313 mutex_unlock(tfm_mutex); 2314 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2315 "context; rc = [%d]\n", rc); 2316 goto out; 2317 } 2318 2319 req = skcipher_request_alloc(tfm, GFP_KERNEL); 2320 if (!req) { 2321 mutex_unlock(tfm_mutex); 2322 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " 2323 "attempting to skcipher_request_alloc for " 2324 "%s\n", crypto_skcipher_driver_name(tfm)); 2325 rc = -ENOMEM; 2326 goto out; 2327 } 2328 2329 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 2330 NULL, NULL); 2331 2332 rc = 0; 2333 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2334 crypt_stat->key_size); 2335 skcipher_request_set_crypt(req, src_sg, dst_sg, 2336 (*key_rec).enc_key_size, NULL); 2337 rc = crypto_skcipher_encrypt(req); 2338 mutex_unlock(tfm_mutex); 2339 skcipher_request_free(req); 2340 if (rc) { 2341 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2342 goto out; 2343 } 2344 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2345 if (ecryptfs_verbosity > 0) { 2346 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2347 key_rec->enc_key_size); 2348 ecryptfs_dump_hex(key_rec->enc_key, 2349 key_rec->enc_key_size); 2350 } 2351 encrypted_session_key_set: 2352 /* This format is inspired by OpenPGP; see RFC 2440 2353 * packet tag 3 */ 2354 max_packet_size = (1 /* Tag 3 identifier */ 2355 + 3 /* Max Tag 3 packet size */ 2356 + 1 /* Version */ 2357 + 1 /* Cipher code */ 2358 + 1 /* S2K specifier */ 2359 + 1 /* Hash identifier */ 2360 + ECRYPTFS_SALT_SIZE /* Salt */ 2361 + 1 /* Hash iterations */ 2362 + key_rec->enc_key_size); /* Encrypted key size */ 2363 if (max_packet_size > (*remaining_bytes)) { 2364 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2365 "there are only [%td] available\n", max_packet_size, 2366 (*remaining_bytes)); 2367 rc = -EINVAL; 2368 goto out; 2369 } 2370 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2371 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2372 * to get the number of octets in the actual Tag 3 packet */ 2373 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2374 (max_packet_size - 4), 2375 &packet_size_length); 2376 if (rc) { 2377 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2378 "generate packet length. rc = [%d]\n", rc); 2379 goto out; 2380 } 2381 (*packet_size) += packet_size_length; 2382 dest[(*packet_size)++] = 0x04; /* version 4 */ 2383 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2384 * specified with strings */ 2385 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2386 crypt_stat->key_size); 2387 if (cipher_code == 0) { 2388 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2389 "cipher [%s]\n", crypt_stat->cipher); 2390 rc = -EINVAL; 2391 goto out; 2392 } 2393 dest[(*packet_size)++] = cipher_code; 2394 dest[(*packet_size)++] = 0x03; /* S2K */ 2395 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2396 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2397 ECRYPTFS_SALT_SIZE); 2398 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2399 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2400 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2401 key_rec->enc_key_size); 2402 (*packet_size) += key_rec->enc_key_size; 2403 out: 2404 if (rc) 2405 (*packet_size) = 0; 2406 else 2407 (*remaining_bytes) -= (*packet_size); 2408 return rc; 2409 } 2410 2411 struct kmem_cache *ecryptfs_key_record_cache; 2412 2413 /** 2414 * ecryptfs_generate_key_packet_set 2415 * @dest_base: Virtual address from which to write the key record set 2416 * @crypt_stat: The cryptographic context from which the 2417 * authentication tokens will be retrieved 2418 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2419 * for the global parameters 2420 * @len: The amount written 2421 * @max: The maximum amount of data allowed to be written 2422 * 2423 * Generates a key packet set and writes it to the virtual address 2424 * passed in. 2425 * 2426 * Returns zero on success; non-zero on error. 2427 */ 2428 int 2429 ecryptfs_generate_key_packet_set(char *dest_base, 2430 struct ecryptfs_crypt_stat *crypt_stat, 2431 struct dentry *ecryptfs_dentry, size_t *len, 2432 size_t max) 2433 { 2434 struct ecryptfs_auth_tok *auth_tok; 2435 struct key *auth_tok_key = NULL; 2436 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2437 &ecryptfs_superblock_to_private( 2438 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2439 size_t written; 2440 struct ecryptfs_key_record *key_rec; 2441 struct ecryptfs_key_sig *key_sig; 2442 int rc = 0; 2443 2444 (*len) = 0; 2445 mutex_lock(&crypt_stat->keysig_list_mutex); 2446 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2447 if (!key_rec) { 2448 rc = -ENOMEM; 2449 goto out; 2450 } 2451 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2452 crypt_stat_list) { 2453 memset(key_rec, 0, sizeof(*key_rec)); 2454 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2455 &auth_tok, 2456 mount_crypt_stat, 2457 key_sig->keysig); 2458 if (rc) { 2459 printk(KERN_WARNING "Unable to retrieve auth tok with " 2460 "sig = [%s]\n", key_sig->keysig); 2461 rc = process_find_global_auth_tok_for_sig_err(rc); 2462 goto out_free; 2463 } 2464 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2465 rc = write_tag_3_packet((dest_base + (*len)), 2466 &max, auth_tok, 2467 crypt_stat, key_rec, 2468 &written); 2469 up_write(&(auth_tok_key->sem)); 2470 key_put(auth_tok_key); 2471 if (rc) { 2472 ecryptfs_printk(KERN_WARNING, "Error " 2473 "writing tag 3 packet\n"); 2474 goto out_free; 2475 } 2476 (*len) += written; 2477 /* Write auth tok signature packet */ 2478 rc = write_tag_11_packet((dest_base + (*len)), &max, 2479 key_rec->sig, 2480 ECRYPTFS_SIG_SIZE, &written); 2481 if (rc) { 2482 ecryptfs_printk(KERN_ERR, "Error writing " 2483 "auth tok signature packet\n"); 2484 goto out_free; 2485 } 2486 (*len) += written; 2487 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2488 rc = write_tag_1_packet(dest_base + (*len), &max, 2489 auth_tok_key, auth_tok, 2490 crypt_stat, key_rec, &written); 2491 if (rc) { 2492 ecryptfs_printk(KERN_WARNING, "Error " 2493 "writing tag 1 packet\n"); 2494 goto out_free; 2495 } 2496 (*len) += written; 2497 } else { 2498 up_write(&(auth_tok_key->sem)); 2499 key_put(auth_tok_key); 2500 ecryptfs_printk(KERN_WARNING, "Unsupported " 2501 "authentication token type\n"); 2502 rc = -EINVAL; 2503 goto out_free; 2504 } 2505 } 2506 if (likely(max > 0)) { 2507 dest_base[(*len)] = 0x00; 2508 } else { 2509 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2510 rc = -EIO; 2511 } 2512 out_free: 2513 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2514 out: 2515 if (rc) 2516 (*len) = 0; 2517 mutex_unlock(&crypt_stat->keysig_list_mutex); 2518 return rc; 2519 } 2520 2521 struct kmem_cache *ecryptfs_key_sig_cache; 2522 2523 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2524 { 2525 struct ecryptfs_key_sig *new_key_sig; 2526 2527 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2528 if (!new_key_sig) { 2529 printk(KERN_ERR 2530 "Error allocating from ecryptfs_key_sig_cache\n"); 2531 return -ENOMEM; 2532 } 2533 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2534 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2535 /* Caller must hold keysig_list_mutex */ 2536 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2537 2538 return 0; 2539 } 2540 2541 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2542 2543 int 2544 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2545 char *sig, u32 global_auth_tok_flags) 2546 { 2547 struct ecryptfs_global_auth_tok *new_auth_tok; 2548 int rc = 0; 2549 2550 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2551 GFP_KERNEL); 2552 if (!new_auth_tok) { 2553 rc = -ENOMEM; 2554 printk(KERN_ERR "Error allocating from " 2555 "ecryptfs_global_auth_tok_cache\n"); 2556 goto out; 2557 } 2558 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2559 new_auth_tok->flags = global_auth_tok_flags; 2560 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2561 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2562 list_add(&new_auth_tok->mount_crypt_stat_list, 2563 &mount_crypt_stat->global_auth_tok_list); 2564 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2565 out: 2566 return rc; 2567 } 2568 2569