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 return -ENOMEM; 644 645 (*packet_size) = 0; 646 rc = ecryptfs_find_auth_tok_for_sig( 647 &auth_tok_key, 648 &s->auth_tok, mount_crypt_stat, 649 mount_crypt_stat->global_default_fnek_sig); 650 if (rc) { 651 printk(KERN_ERR "%s: Error attempting to find auth tok for " 652 "fnek sig [%s]; rc = [%d]\n", __func__, 653 mount_crypt_stat->global_default_fnek_sig, rc); 654 goto out; 655 } 656 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( 657 &s->skcipher_tfm, 658 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); 659 if (unlikely(rc)) { 660 printk(KERN_ERR "Internal error whilst attempting to get " 661 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 662 mount_crypt_stat->global_default_fn_cipher_name, rc); 663 goto out; 664 } 665 mutex_lock(s->tfm_mutex); 666 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm); 667 /* Plus one for the \0 separator between the random prefix 668 * and the plaintext filename */ 669 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); 670 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); 671 if ((s->block_aligned_filename_size % s->block_size) != 0) { 672 s->num_rand_bytes += (s->block_size 673 - (s->block_aligned_filename_size 674 % s->block_size)); 675 s->block_aligned_filename_size = (s->num_rand_bytes 676 + filename_size); 677 } 678 /* Octet 0: Tag 70 identifier 679 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 680 * and block-aligned encrypted filename size) 681 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 682 * Octet N2-N3: Cipher identifier (1 octet) 683 * Octets N3-N4: Block-aligned encrypted filename 684 * - Consists of a minimum number of random characters, a \0 685 * separator, and then the filename */ 686 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE 687 + s->block_aligned_filename_size); 688 if (!dest) { 689 (*packet_size) = s->max_packet_size; 690 goto out_unlock; 691 } 692 if (s->max_packet_size > (*remaining_bytes)) { 693 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " 694 "[%zd] available\n", __func__, s->max_packet_size, 695 (*remaining_bytes)); 696 rc = -EINVAL; 697 goto out_unlock; 698 } 699 700 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 701 if (!s->skcipher_req) { 702 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 703 "skcipher_request_alloc for %s\n", __func__, 704 crypto_skcipher_driver_name(s->skcipher_tfm)); 705 rc = -ENOMEM; 706 goto out_unlock; 707 } 708 709 skcipher_request_set_callback(s->skcipher_req, 710 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 711 712 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, 713 GFP_KERNEL); 714 if (!s->block_aligned_filename) { 715 rc = -ENOMEM; 716 goto out_unlock; 717 } 718 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; 719 rc = ecryptfs_write_packet_length(&dest[s->i], 720 (ECRYPTFS_SIG_SIZE 721 + 1 /* Cipher code */ 722 + s->block_aligned_filename_size), 723 &s->packet_size_len); 724 if (rc) { 725 printk(KERN_ERR "%s: Error generating tag 70 packet " 726 "header; cannot generate packet length; rc = [%d]\n", 727 __func__, rc); 728 goto out_free_unlock; 729 } 730 s->i += s->packet_size_len; 731 ecryptfs_from_hex(&dest[s->i], 732 mount_crypt_stat->global_default_fnek_sig, 733 ECRYPTFS_SIG_SIZE); 734 s->i += ECRYPTFS_SIG_SIZE; 735 s->cipher_code = ecryptfs_code_for_cipher_string( 736 mount_crypt_stat->global_default_fn_cipher_name, 737 mount_crypt_stat->global_default_fn_cipher_key_bytes); 738 if (s->cipher_code == 0) { 739 printk(KERN_WARNING "%s: Unable to generate code for " 740 "cipher [%s] with key bytes [%zd]\n", __func__, 741 mount_crypt_stat->global_default_fn_cipher_name, 742 mount_crypt_stat->global_default_fn_cipher_key_bytes); 743 rc = -EINVAL; 744 goto out_free_unlock; 745 } 746 dest[s->i++] = s->cipher_code; 747 /* TODO: Support other key modules than passphrase for 748 * filename encryption */ 749 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 750 rc = -EOPNOTSUPP; 751 printk(KERN_INFO "%s: Filename encryption only supports " 752 "password tokens\n", __func__); 753 goto out_free_unlock; 754 } 755 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0); 756 if (IS_ERR(s->hash_tfm)) { 757 rc = PTR_ERR(s->hash_tfm); 758 printk(KERN_ERR "%s: Error attempting to " 759 "allocate hash crypto context; rc = [%d]\n", 760 __func__, rc); 761 goto out_free_unlock; 762 } 763 764 s->hash_desc = kmalloc(sizeof(*s->hash_desc) + 765 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL); 766 if (!s->hash_desc) { 767 rc = -ENOMEM; 768 goto out_release_free_unlock; 769 } 770 771 s->hash_desc->tfm = s->hash_tfm; 772 s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; 773 774 rc = crypto_shash_digest(s->hash_desc, 775 (u8 *)s->auth_tok->token.password.session_key_encryption_key, 776 s->auth_tok->token.password.session_key_encryption_key_bytes, 777 s->hash); 778 if (rc) { 779 printk(KERN_ERR 780 "%s: Error computing crypto hash; rc = [%d]\n", 781 __func__, rc); 782 goto out_release_free_unlock; 783 } 784 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { 785 s->block_aligned_filename[s->j] = 786 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; 787 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) 788 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { 789 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash, 790 ECRYPTFS_TAG_70_DIGEST_SIZE, 791 s->tmp_hash); 792 if (rc) { 793 printk(KERN_ERR 794 "%s: Error computing crypto hash; " 795 "rc = [%d]\n", __func__, rc); 796 goto out_release_free_unlock; 797 } 798 memcpy(s->hash, s->tmp_hash, 799 ECRYPTFS_TAG_70_DIGEST_SIZE); 800 } 801 if (s->block_aligned_filename[s->j] == '\0') 802 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; 803 } 804 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, 805 filename_size); 806 rc = virt_to_scatterlist(s->block_aligned_filename, 807 s->block_aligned_filename_size, s->src_sg, 2); 808 if (rc < 1) { 809 printk(KERN_ERR "%s: Internal error whilst attempting to " 810 "convert filename memory to scatterlist; rc = [%d]. " 811 "block_aligned_filename_size = [%zd]\n", __func__, rc, 812 s->block_aligned_filename_size); 813 goto out_release_free_unlock; 814 } 815 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, 816 s->dst_sg, 2); 817 if (rc < 1) { 818 printk(KERN_ERR "%s: Internal error whilst attempting to " 819 "convert encrypted filename memory to scatterlist; " 820 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 821 __func__, rc, s->block_aligned_filename_size); 822 goto out_release_free_unlock; 823 } 824 /* The characters in the first block effectively do the job 825 * of the IV here, so we just use 0's for the IV. Note the 826 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 827 * >= ECRYPTFS_MAX_IV_BYTES. */ 828 rc = crypto_skcipher_setkey( 829 s->skcipher_tfm, 830 s->auth_tok->token.password.session_key_encryption_key, 831 mount_crypt_stat->global_default_fn_cipher_key_bytes); 832 if (rc < 0) { 833 printk(KERN_ERR "%s: Error setting key for crypto context; " 834 "rc = [%d]. s->auth_tok->token.password.session_key_" 835 "encryption_key = [0x%p]; mount_crypt_stat->" 836 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 837 rc, 838 s->auth_tok->token.password.session_key_encryption_key, 839 mount_crypt_stat->global_default_fn_cipher_key_bytes); 840 goto out_release_free_unlock; 841 } 842 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 843 s->block_aligned_filename_size, s->iv); 844 rc = crypto_skcipher_encrypt(s->skcipher_req); 845 if (rc) { 846 printk(KERN_ERR "%s: Error attempting to encrypt filename; " 847 "rc = [%d]\n", __func__, rc); 848 goto out_release_free_unlock; 849 } 850 s->i += s->block_aligned_filename_size; 851 (*packet_size) = s->i; 852 (*remaining_bytes) -= (*packet_size); 853 out_release_free_unlock: 854 crypto_free_shash(s->hash_tfm); 855 out_free_unlock: 856 kzfree(s->block_aligned_filename); 857 out_unlock: 858 mutex_unlock(s->tfm_mutex); 859 out: 860 if (auth_tok_key) { 861 up_write(&(auth_tok_key->sem)); 862 key_put(auth_tok_key); 863 } 864 skcipher_request_free(s->skcipher_req); 865 kzfree(s->hash_desc); 866 kfree(s); 867 return rc; 868 } 869 870 struct ecryptfs_parse_tag_70_packet_silly_stack { 871 u8 cipher_code; 872 size_t max_packet_size; 873 size_t packet_size_len; 874 size_t parsed_tag_70_packet_size; 875 size_t block_aligned_filename_size; 876 size_t block_size; 877 size_t i; 878 struct mutex *tfm_mutex; 879 char *decrypted_filename; 880 struct ecryptfs_auth_tok *auth_tok; 881 struct scatterlist src_sg[2]; 882 struct scatterlist dst_sg[2]; 883 struct crypto_skcipher *skcipher_tfm; 884 struct skcipher_request *skcipher_req; 885 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; 886 char iv[ECRYPTFS_MAX_IV_BYTES]; 887 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; 888 }; 889 890 /** 891 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet 892 * @filename: This function kmalloc's the memory for the filename 893 * @filename_size: This function sets this to the amount of memory 894 * kmalloc'd for the filename 895 * @packet_size: This function sets this to the the number of octets 896 * in the packet parsed 897 * @mount_crypt_stat: The mount-wide cryptographic context 898 * @data: The memory location containing the start of the tag 70 899 * packet 900 * @max_packet_size: The maximum legal size of the packet to be parsed 901 * from @data 902 * 903 * Returns zero on success; non-zero otherwise 904 */ 905 int 906 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, 907 size_t *packet_size, 908 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 909 char *data, size_t max_packet_size) 910 { 911 struct ecryptfs_parse_tag_70_packet_silly_stack *s; 912 struct key *auth_tok_key = NULL; 913 int rc = 0; 914 915 (*packet_size) = 0; 916 (*filename_size) = 0; 917 (*filename) = NULL; 918 s = kzalloc(sizeof(*s), GFP_KERNEL); 919 if (!s) 920 return -ENOMEM; 921 922 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { 923 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " 924 "at least [%d]\n", __func__, max_packet_size, 925 ECRYPTFS_TAG_70_MIN_METADATA_SIZE); 926 rc = -EINVAL; 927 goto out; 928 } 929 /* Octet 0: Tag 70 identifier 930 * Octets 1-N1: Tag 70 packet size (includes cipher identifier 931 * and block-aligned encrypted filename size) 932 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) 933 * Octet N2-N3: Cipher identifier (1 octet) 934 * Octets N3-N4: Block-aligned encrypted filename 935 * - Consists of a minimum number of random numbers, a \0 936 * separator, and then the filename */ 937 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { 938 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " 939 "tag [0x%.2x]\n", __func__, 940 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); 941 rc = -EINVAL; 942 goto out; 943 } 944 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], 945 &s->parsed_tag_70_packet_size, 946 &s->packet_size_len); 947 if (rc) { 948 printk(KERN_WARNING "%s: Error parsing packet length; " 949 "rc = [%d]\n", __func__, rc); 950 goto out; 951 } 952 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size 953 - ECRYPTFS_SIG_SIZE - 1); 954 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) 955 > max_packet_size) { 956 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " 957 "size is [%zd]\n", __func__, max_packet_size, 958 (1 + s->packet_size_len + 1 959 + s->block_aligned_filename_size)); 960 rc = -EINVAL; 961 goto out; 962 } 963 (*packet_size) += s->packet_size_len; 964 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], 965 ECRYPTFS_SIG_SIZE); 966 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 967 (*packet_size) += ECRYPTFS_SIG_SIZE; 968 s->cipher_code = data[(*packet_size)++]; 969 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); 970 if (rc) { 971 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", 972 __func__, s->cipher_code); 973 goto out; 974 } 975 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 976 &s->auth_tok, mount_crypt_stat, 977 s->fnek_sig_hex); 978 if (rc) { 979 printk(KERN_ERR "%s: Error attempting to find auth tok for " 980 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, 981 rc); 982 goto out; 983 } 984 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm, 985 &s->tfm_mutex, 986 s->cipher_string); 987 if (unlikely(rc)) { 988 printk(KERN_ERR "Internal error whilst attempting to get " 989 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 990 s->cipher_string, rc); 991 goto out; 992 } 993 mutex_lock(s->tfm_mutex); 994 rc = virt_to_scatterlist(&data[(*packet_size)], 995 s->block_aligned_filename_size, s->src_sg, 2); 996 if (rc < 1) { 997 printk(KERN_ERR "%s: Internal error whilst attempting to " 998 "convert encrypted filename memory to scatterlist; " 999 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1000 __func__, rc, s->block_aligned_filename_size); 1001 goto out_unlock; 1002 } 1003 (*packet_size) += s->block_aligned_filename_size; 1004 s->decrypted_filename = kmalloc(s->block_aligned_filename_size, 1005 GFP_KERNEL); 1006 if (!s->decrypted_filename) { 1007 rc = -ENOMEM; 1008 goto out_unlock; 1009 } 1010 rc = virt_to_scatterlist(s->decrypted_filename, 1011 s->block_aligned_filename_size, s->dst_sg, 2); 1012 if (rc < 1) { 1013 printk(KERN_ERR "%s: Internal error whilst attempting to " 1014 "convert decrypted filename memory to scatterlist; " 1015 "rc = [%d]. block_aligned_filename_size = [%zd]\n", 1016 __func__, rc, s->block_aligned_filename_size); 1017 goto out_free_unlock; 1018 } 1019 1020 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); 1021 if (!s->skcipher_req) { 1022 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1023 "skcipher_request_alloc for %s\n", __func__, 1024 crypto_skcipher_driver_name(s->skcipher_tfm)); 1025 rc = -ENOMEM; 1026 goto out_free_unlock; 1027 } 1028 1029 skcipher_request_set_callback(s->skcipher_req, 1030 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 1031 1032 /* The characters in the first block effectively do the job of 1033 * the IV here, so we just use 0's for the IV. Note the 1034 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 1035 * >= ECRYPTFS_MAX_IV_BYTES. */ 1036 /* TODO: Support other key modules than passphrase for 1037 * filename encryption */ 1038 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { 1039 rc = -EOPNOTSUPP; 1040 printk(KERN_INFO "%s: Filename encryption only supports " 1041 "password tokens\n", __func__); 1042 goto out_free_unlock; 1043 } 1044 rc = crypto_skcipher_setkey( 1045 s->skcipher_tfm, 1046 s->auth_tok->token.password.session_key_encryption_key, 1047 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1048 if (rc < 0) { 1049 printk(KERN_ERR "%s: Error setting key for crypto context; " 1050 "rc = [%d]. s->auth_tok->token.password.session_key_" 1051 "encryption_key = [0x%p]; mount_crypt_stat->" 1052 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, 1053 rc, 1054 s->auth_tok->token.password.session_key_encryption_key, 1055 mount_crypt_stat->global_default_fn_cipher_key_bytes); 1056 goto out_free_unlock; 1057 } 1058 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, 1059 s->block_aligned_filename_size, s->iv); 1060 rc = crypto_skcipher_decrypt(s->skcipher_req); 1061 if (rc) { 1062 printk(KERN_ERR "%s: Error attempting to decrypt filename; " 1063 "rc = [%d]\n", __func__, rc); 1064 goto out_free_unlock; 1065 } 1066 while (s->decrypted_filename[s->i] != '\0' 1067 && s->i < s->block_aligned_filename_size) 1068 s->i++; 1069 if (s->i == s->block_aligned_filename_size) { 1070 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " 1071 "find valid separator between random characters and " 1072 "the filename\n", __func__); 1073 rc = -EINVAL; 1074 goto out_free_unlock; 1075 } 1076 s->i++; 1077 (*filename_size) = (s->block_aligned_filename_size - s->i); 1078 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { 1079 printk(KERN_WARNING "%s: Filename size is [%zd], which is " 1080 "invalid\n", __func__, (*filename_size)); 1081 rc = -EINVAL; 1082 goto out_free_unlock; 1083 } 1084 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); 1085 if (!(*filename)) { 1086 rc = -ENOMEM; 1087 goto out_free_unlock; 1088 } 1089 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); 1090 (*filename)[(*filename_size)] = '\0'; 1091 out_free_unlock: 1092 kfree(s->decrypted_filename); 1093 out_unlock: 1094 mutex_unlock(s->tfm_mutex); 1095 out: 1096 if (rc) { 1097 (*packet_size) = 0; 1098 (*filename_size) = 0; 1099 (*filename) = NULL; 1100 } 1101 if (auth_tok_key) { 1102 up_write(&(auth_tok_key->sem)); 1103 key_put(auth_tok_key); 1104 } 1105 skcipher_request_free(s->skcipher_req); 1106 kfree(s); 1107 return rc; 1108 } 1109 1110 static int 1111 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) 1112 { 1113 int rc = 0; 1114 1115 (*sig) = NULL; 1116 switch (auth_tok->token_type) { 1117 case ECRYPTFS_PASSWORD: 1118 (*sig) = auth_tok->token.password.signature; 1119 break; 1120 case ECRYPTFS_PRIVATE_KEY: 1121 (*sig) = auth_tok->token.private_key.signature; 1122 break; 1123 default: 1124 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", 1125 auth_tok->token_type); 1126 rc = -EINVAL; 1127 } 1128 return rc; 1129 } 1130 1131 /** 1132 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. 1133 * @auth_tok: The key authentication token used to decrypt the session key 1134 * @crypt_stat: The cryptographic context 1135 * 1136 * Returns zero on success; non-zero error otherwise. 1137 */ 1138 static int 1139 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1140 struct ecryptfs_crypt_stat *crypt_stat) 1141 { 1142 u8 cipher_code = 0; 1143 struct ecryptfs_msg_ctx *msg_ctx; 1144 struct ecryptfs_message *msg = NULL; 1145 char *auth_tok_sig; 1146 char *payload = NULL; 1147 size_t payload_len = 0; 1148 int rc; 1149 1150 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); 1151 if (rc) { 1152 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", 1153 auth_tok->token_type); 1154 goto out; 1155 } 1156 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), 1157 &payload, &payload_len); 1158 if (rc) { 1159 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); 1160 goto out; 1161 } 1162 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1163 if (rc) { 1164 ecryptfs_printk(KERN_ERR, "Error sending message to " 1165 "ecryptfsd: %d\n", rc); 1166 goto out; 1167 } 1168 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 1169 if (rc) { 1170 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " 1171 "from the user space daemon\n"); 1172 rc = -EIO; 1173 goto out; 1174 } 1175 rc = parse_tag_65_packet(&(auth_tok->session_key), 1176 &cipher_code, msg); 1177 if (rc) { 1178 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", 1179 rc); 1180 goto out; 1181 } 1182 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1183 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1184 auth_tok->session_key.decrypted_key_size); 1185 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; 1186 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); 1187 if (rc) { 1188 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", 1189 cipher_code) 1190 goto out; 1191 } 1192 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1193 if (ecryptfs_verbosity > 0) { 1194 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); 1195 ecryptfs_dump_hex(crypt_stat->key, 1196 crypt_stat->key_size); 1197 } 1198 out: 1199 kfree(msg); 1200 kfree(payload); 1201 return rc; 1202 } 1203 1204 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) 1205 { 1206 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1207 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1208 1209 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, 1210 auth_tok_list_head, list) { 1211 list_del(&auth_tok_list_item->list); 1212 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1213 auth_tok_list_item); 1214 } 1215 } 1216 1217 struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 1218 1219 /** 1220 * parse_tag_1_packet 1221 * @crypt_stat: The cryptographic context to modify based on packet contents 1222 * @data: The raw bytes of the packet. 1223 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1224 * a new authentication token will be placed at the 1225 * end of this list for this packet. 1226 * @new_auth_tok: Pointer to a pointer to memory that this function 1227 * allocates; sets the memory address of the pointer to 1228 * NULL on error. This object is added to the 1229 * auth_tok_list. 1230 * @packet_size: This function writes the size of the parsed packet 1231 * into this memory location; zero on error. 1232 * @max_packet_size: The maximum allowable packet size 1233 * 1234 * Returns zero on success; non-zero on error. 1235 */ 1236 static int 1237 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, 1238 unsigned char *data, struct list_head *auth_tok_list, 1239 struct ecryptfs_auth_tok **new_auth_tok, 1240 size_t *packet_size, size_t max_packet_size) 1241 { 1242 size_t body_size; 1243 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1244 size_t length_size; 1245 int rc = 0; 1246 1247 (*packet_size) = 0; 1248 (*new_auth_tok) = NULL; 1249 /** 1250 * This format is inspired by OpenPGP; see RFC 2440 1251 * packet tag 1 1252 * 1253 * Tag 1 identifier (1 byte) 1254 * Max Tag 1 packet size (max 3 bytes) 1255 * Version (1 byte) 1256 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) 1257 * Cipher identifier (1 byte) 1258 * Encrypted key size (arbitrary) 1259 * 1260 * 12 bytes minimum packet size 1261 */ 1262 if (unlikely(max_packet_size < 12)) { 1263 printk(KERN_ERR "Invalid max packet size; must be >=12\n"); 1264 rc = -EINVAL; 1265 goto out; 1266 } 1267 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { 1268 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", 1269 ECRYPTFS_TAG_1_PACKET_TYPE); 1270 rc = -EINVAL; 1271 goto out; 1272 } 1273 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1274 * at end of function upon failure */ 1275 auth_tok_list_item = 1276 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, 1277 GFP_KERNEL); 1278 if (!auth_tok_list_item) { 1279 printk(KERN_ERR "Unable to allocate memory\n"); 1280 rc = -ENOMEM; 1281 goto out; 1282 } 1283 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1284 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1285 &length_size); 1286 if (rc) { 1287 printk(KERN_WARNING "Error parsing packet length; " 1288 "rc = [%d]\n", rc); 1289 goto out_free; 1290 } 1291 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { 1292 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1293 rc = -EINVAL; 1294 goto out_free; 1295 } 1296 (*packet_size) += length_size; 1297 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1298 printk(KERN_WARNING "Packet size exceeds max\n"); 1299 rc = -EINVAL; 1300 goto out_free; 1301 } 1302 if (unlikely(data[(*packet_size)++] != 0x03)) { 1303 printk(KERN_WARNING "Unknown version number [%d]\n", 1304 data[(*packet_size) - 1]); 1305 rc = -EINVAL; 1306 goto out_free; 1307 } 1308 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, 1309 &data[(*packet_size)], ECRYPTFS_SIG_SIZE); 1310 *packet_size += ECRYPTFS_SIG_SIZE; 1311 /* This byte is skipped because the kernel does not need to 1312 * know which public key encryption algorithm was used */ 1313 (*packet_size)++; 1314 (*new_auth_tok)->session_key.encrypted_key_size = 1315 body_size - (ECRYPTFS_SIG_SIZE + 2); 1316 if ((*new_auth_tok)->session_key.encrypted_key_size 1317 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1318 printk(KERN_WARNING "Tag 1 packet contains key larger " 1319 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1320 rc = -EINVAL; 1321 goto out; 1322 } 1323 memcpy((*new_auth_tok)->session_key.encrypted_key, 1324 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); 1325 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; 1326 (*new_auth_tok)->session_key.flags &= 1327 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1328 (*new_auth_tok)->session_key.flags |= 1329 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1330 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; 1331 (*new_auth_tok)->flags = 0; 1332 (*new_auth_tok)->session_key.flags &= 1333 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1334 (*new_auth_tok)->session_key.flags &= 1335 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1336 list_add(&auth_tok_list_item->list, auth_tok_list); 1337 goto out; 1338 out_free: 1339 (*new_auth_tok) = NULL; 1340 memset(auth_tok_list_item, 0, 1341 sizeof(struct ecryptfs_auth_tok_list_item)); 1342 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1343 auth_tok_list_item); 1344 out: 1345 if (rc) 1346 (*packet_size) = 0; 1347 return rc; 1348 } 1349 1350 /** 1351 * parse_tag_3_packet 1352 * @crypt_stat: The cryptographic context to modify based on packet 1353 * contents. 1354 * @data: The raw bytes of the packet. 1355 * @auth_tok_list: eCryptfs parses packets into authentication tokens; 1356 * a new authentication token will be placed at the end 1357 * of this list for this packet. 1358 * @new_auth_tok: Pointer to a pointer to memory that this function 1359 * allocates; sets the memory address of the pointer to 1360 * NULL on error. This object is added to the 1361 * auth_tok_list. 1362 * @packet_size: This function writes the size of the parsed packet 1363 * into this memory location; zero on error. 1364 * @max_packet_size: maximum number of bytes to parse 1365 * 1366 * Returns zero on success; non-zero on error. 1367 */ 1368 static int 1369 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, 1370 unsigned char *data, struct list_head *auth_tok_list, 1371 struct ecryptfs_auth_tok **new_auth_tok, 1372 size_t *packet_size, size_t max_packet_size) 1373 { 1374 size_t body_size; 1375 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1376 size_t length_size; 1377 int rc = 0; 1378 1379 (*packet_size) = 0; 1380 (*new_auth_tok) = NULL; 1381 /** 1382 *This format is inspired by OpenPGP; see RFC 2440 1383 * packet tag 3 1384 * 1385 * Tag 3 identifier (1 byte) 1386 * Max Tag 3 packet size (max 3 bytes) 1387 * Version (1 byte) 1388 * Cipher code (1 byte) 1389 * S2K specifier (1 byte) 1390 * Hash identifier (1 byte) 1391 * Salt (ECRYPTFS_SALT_SIZE) 1392 * Hash iterations (1 byte) 1393 * Encrypted key (arbitrary) 1394 * 1395 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size 1396 */ 1397 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { 1398 printk(KERN_ERR "Max packet size too large\n"); 1399 rc = -EINVAL; 1400 goto out; 1401 } 1402 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { 1403 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", 1404 ECRYPTFS_TAG_3_PACKET_TYPE); 1405 rc = -EINVAL; 1406 goto out; 1407 } 1408 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or 1409 * at end of function upon failure */ 1410 auth_tok_list_item = 1411 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); 1412 if (!auth_tok_list_item) { 1413 printk(KERN_ERR "Unable to allocate memory\n"); 1414 rc = -ENOMEM; 1415 goto out; 1416 } 1417 (*new_auth_tok) = &auth_tok_list_item->auth_tok; 1418 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1419 &length_size); 1420 if (rc) { 1421 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", 1422 rc); 1423 goto out_free; 1424 } 1425 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { 1426 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1427 rc = -EINVAL; 1428 goto out_free; 1429 } 1430 (*packet_size) += length_size; 1431 if (unlikely((*packet_size) + body_size > max_packet_size)) { 1432 printk(KERN_ERR "Packet size exceeds max\n"); 1433 rc = -EINVAL; 1434 goto out_free; 1435 } 1436 (*new_auth_tok)->session_key.encrypted_key_size = 1437 (body_size - (ECRYPTFS_SALT_SIZE + 5)); 1438 if ((*new_auth_tok)->session_key.encrypted_key_size 1439 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { 1440 printk(KERN_WARNING "Tag 3 packet contains key larger " 1441 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); 1442 rc = -EINVAL; 1443 goto out_free; 1444 } 1445 if (unlikely(data[(*packet_size)++] != 0x04)) { 1446 printk(KERN_WARNING "Unknown version number [%d]\n", 1447 data[(*packet_size) - 1]); 1448 rc = -EINVAL; 1449 goto out_free; 1450 } 1451 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, 1452 (u16)data[(*packet_size)]); 1453 if (rc) 1454 goto out_free; 1455 /* A little extra work to differentiate among the AES key 1456 * sizes; see RFC2440 */ 1457 switch(data[(*packet_size)++]) { 1458 case RFC2440_CIPHER_AES_192: 1459 crypt_stat->key_size = 24; 1460 break; 1461 default: 1462 crypt_stat->key_size = 1463 (*new_auth_tok)->session_key.encrypted_key_size; 1464 } 1465 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1466 if (rc) 1467 goto out_free; 1468 if (unlikely(data[(*packet_size)++] != 0x03)) { 1469 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); 1470 rc = -ENOSYS; 1471 goto out_free; 1472 } 1473 /* TODO: finish the hash mapping */ 1474 switch (data[(*packet_size)++]) { 1475 case 0x01: /* See RFC2440 for these numbers and their mappings */ 1476 /* Choose MD5 */ 1477 memcpy((*new_auth_tok)->token.password.salt, 1478 &data[(*packet_size)], ECRYPTFS_SALT_SIZE); 1479 (*packet_size) += ECRYPTFS_SALT_SIZE; 1480 /* This conversion was taken straight from RFC2440 */ 1481 (*new_auth_tok)->token.password.hash_iterations = 1482 ((u32) 16 + (data[(*packet_size)] & 15)) 1483 << ((data[(*packet_size)] >> 4) + 6); 1484 (*packet_size)++; 1485 /* Friendly reminder: 1486 * (*new_auth_tok)->session_key.encrypted_key_size = 1487 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ 1488 memcpy((*new_auth_tok)->session_key.encrypted_key, 1489 &data[(*packet_size)], 1490 (*new_auth_tok)->session_key.encrypted_key_size); 1491 (*packet_size) += 1492 (*new_auth_tok)->session_key.encrypted_key_size; 1493 (*new_auth_tok)->session_key.flags &= 1494 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1495 (*new_auth_tok)->session_key.flags |= 1496 ECRYPTFS_CONTAINS_ENCRYPTED_KEY; 1497 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ 1498 break; 1499 default: 1500 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " 1501 "[%d]\n", data[(*packet_size) - 1]); 1502 rc = -ENOSYS; 1503 goto out_free; 1504 } 1505 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; 1506 /* TODO: Parametarize; we might actually want userspace to 1507 * decrypt the session key. */ 1508 (*new_auth_tok)->session_key.flags &= 1509 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); 1510 (*new_auth_tok)->session_key.flags &= 1511 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); 1512 list_add(&auth_tok_list_item->list, auth_tok_list); 1513 goto out; 1514 out_free: 1515 (*new_auth_tok) = NULL; 1516 memset(auth_tok_list_item, 0, 1517 sizeof(struct ecryptfs_auth_tok_list_item)); 1518 kmem_cache_free(ecryptfs_auth_tok_list_item_cache, 1519 auth_tok_list_item); 1520 out: 1521 if (rc) 1522 (*packet_size) = 0; 1523 return rc; 1524 } 1525 1526 /** 1527 * parse_tag_11_packet 1528 * @data: The raw bytes of the packet 1529 * @contents: This function writes the data contents of the literal 1530 * packet into this memory location 1531 * @max_contents_bytes: The maximum number of bytes that this function 1532 * is allowed to write into contents 1533 * @tag_11_contents_size: This function writes the size of the parsed 1534 * contents into this memory location; zero on 1535 * error 1536 * @packet_size: This function writes the size of the parsed packet 1537 * into this memory location; zero on error 1538 * @max_packet_size: maximum number of bytes to parse 1539 * 1540 * Returns zero on success; non-zero on error. 1541 */ 1542 static int 1543 parse_tag_11_packet(unsigned char *data, unsigned char *contents, 1544 size_t max_contents_bytes, size_t *tag_11_contents_size, 1545 size_t *packet_size, size_t max_packet_size) 1546 { 1547 size_t body_size; 1548 size_t length_size; 1549 int rc = 0; 1550 1551 (*packet_size) = 0; 1552 (*tag_11_contents_size) = 0; 1553 /* This format is inspired by OpenPGP; see RFC 2440 1554 * packet tag 11 1555 * 1556 * Tag 11 identifier (1 byte) 1557 * Max Tag 11 packet size (max 3 bytes) 1558 * Binary format specifier (1 byte) 1559 * Filename length (1 byte) 1560 * Filename ("_CONSOLE") (8 bytes) 1561 * Modification date (4 bytes) 1562 * Literal data (arbitrary) 1563 * 1564 * We need at least 16 bytes of data for the packet to even be 1565 * valid. 1566 */ 1567 if (max_packet_size < 16) { 1568 printk(KERN_ERR "Maximum packet size too small\n"); 1569 rc = -EINVAL; 1570 goto out; 1571 } 1572 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { 1573 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1574 rc = -EINVAL; 1575 goto out; 1576 } 1577 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, 1578 &length_size); 1579 if (rc) { 1580 printk(KERN_WARNING "Invalid tag 11 packet format\n"); 1581 goto out; 1582 } 1583 if (body_size < 14) { 1584 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); 1585 rc = -EINVAL; 1586 goto out; 1587 } 1588 (*packet_size) += length_size; 1589 (*tag_11_contents_size) = (body_size - 14); 1590 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { 1591 printk(KERN_ERR "Packet size exceeds max\n"); 1592 rc = -EINVAL; 1593 goto out; 1594 } 1595 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { 1596 printk(KERN_ERR "Literal data section in tag 11 packet exceeds " 1597 "expected size\n"); 1598 rc = -EINVAL; 1599 goto out; 1600 } 1601 if (data[(*packet_size)++] != 0x62) { 1602 printk(KERN_WARNING "Unrecognizable packet\n"); 1603 rc = -EINVAL; 1604 goto out; 1605 } 1606 if (data[(*packet_size)++] != 0x08) { 1607 printk(KERN_WARNING "Unrecognizable packet\n"); 1608 rc = -EINVAL; 1609 goto out; 1610 } 1611 (*packet_size) += 12; /* Ignore filename and modification date */ 1612 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); 1613 (*packet_size) += (*tag_11_contents_size); 1614 out: 1615 if (rc) { 1616 (*packet_size) = 0; 1617 (*tag_11_contents_size) = 0; 1618 } 1619 return rc; 1620 } 1621 1622 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, 1623 struct ecryptfs_auth_tok **auth_tok, 1624 char *sig) 1625 { 1626 int rc = 0; 1627 1628 (*auth_tok_key) = request_key(&key_type_user, sig, NULL); 1629 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1630 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); 1631 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { 1632 printk(KERN_ERR "Could not find key with description: [%s]\n", 1633 sig); 1634 rc = process_request_key_err(PTR_ERR(*auth_tok_key)); 1635 (*auth_tok_key) = NULL; 1636 goto out; 1637 } 1638 } 1639 down_write(&(*auth_tok_key)->sem); 1640 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); 1641 if (rc) { 1642 up_write(&(*auth_tok_key)->sem); 1643 key_put(*auth_tok_key); 1644 (*auth_tok_key) = NULL; 1645 goto out; 1646 } 1647 out: 1648 return rc; 1649 } 1650 1651 /** 1652 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. 1653 * @auth_tok: The passphrase authentication token to use to encrypt the FEK 1654 * @crypt_stat: The cryptographic context 1655 * 1656 * Returns zero on success; non-zero error otherwise 1657 */ 1658 static int 1659 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, 1660 struct ecryptfs_crypt_stat *crypt_stat) 1661 { 1662 struct scatterlist dst_sg[2]; 1663 struct scatterlist src_sg[2]; 1664 struct mutex *tfm_mutex; 1665 struct crypto_skcipher *tfm; 1666 struct skcipher_request *req = NULL; 1667 int rc = 0; 1668 1669 if (unlikely(ecryptfs_verbosity > 0)) { 1670 ecryptfs_printk( 1671 KERN_DEBUG, "Session key encryption key (size [%d]):\n", 1672 auth_tok->token.password.session_key_encryption_key_bytes); 1673 ecryptfs_dump_hex( 1674 auth_tok->token.password.session_key_encryption_key, 1675 auth_tok->token.password.session_key_encryption_key_bytes); 1676 } 1677 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 1678 crypt_stat->cipher); 1679 if (unlikely(rc)) { 1680 printk(KERN_ERR "Internal error whilst attempting to get " 1681 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 1682 crypt_stat->cipher, rc); 1683 goto out; 1684 } 1685 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, 1686 auth_tok->session_key.encrypted_key_size, 1687 src_sg, 2); 1688 if (rc < 1 || rc > 2) { 1689 printk(KERN_ERR "Internal error whilst attempting to convert " 1690 "auth_tok->session_key.encrypted_key to scatterlist; " 1691 "expected rc = 1; got rc = [%d]. " 1692 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, 1693 auth_tok->session_key.encrypted_key_size); 1694 goto out; 1695 } 1696 auth_tok->session_key.decrypted_key_size = 1697 auth_tok->session_key.encrypted_key_size; 1698 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, 1699 auth_tok->session_key.decrypted_key_size, 1700 dst_sg, 2); 1701 if (rc < 1 || rc > 2) { 1702 printk(KERN_ERR "Internal error whilst attempting to convert " 1703 "auth_tok->session_key.decrypted_key to scatterlist; " 1704 "expected rc = 1; got rc = [%d]\n", rc); 1705 goto out; 1706 } 1707 mutex_lock(tfm_mutex); 1708 req = skcipher_request_alloc(tfm, GFP_KERNEL); 1709 if (!req) { 1710 mutex_unlock(tfm_mutex); 1711 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " 1712 "skcipher_request_alloc for %s\n", __func__, 1713 crypto_skcipher_driver_name(tfm)); 1714 rc = -ENOMEM; 1715 goto out; 1716 } 1717 1718 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 1719 NULL, NULL); 1720 rc = crypto_skcipher_setkey( 1721 tfm, auth_tok->token.password.session_key_encryption_key, 1722 crypt_stat->key_size); 1723 if (unlikely(rc < 0)) { 1724 mutex_unlock(tfm_mutex); 1725 printk(KERN_ERR "Error setting key for crypto context\n"); 1726 rc = -EINVAL; 1727 goto out; 1728 } 1729 skcipher_request_set_crypt(req, src_sg, dst_sg, 1730 auth_tok->session_key.encrypted_key_size, 1731 NULL); 1732 rc = crypto_skcipher_decrypt(req); 1733 mutex_unlock(tfm_mutex); 1734 if (unlikely(rc)) { 1735 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); 1736 goto out; 1737 } 1738 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; 1739 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, 1740 auth_tok->session_key.decrypted_key_size); 1741 crypt_stat->flags |= ECRYPTFS_KEY_VALID; 1742 if (unlikely(ecryptfs_verbosity > 0)) { 1743 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", 1744 crypt_stat->key_size); 1745 ecryptfs_dump_hex(crypt_stat->key, 1746 crypt_stat->key_size); 1747 } 1748 out: 1749 skcipher_request_free(req); 1750 return rc; 1751 } 1752 1753 /** 1754 * ecryptfs_parse_packet_set 1755 * @crypt_stat: The cryptographic context 1756 * @src: Virtual address of region of memory containing the packets 1757 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set 1758 * 1759 * Get crypt_stat to have the file's session key if the requisite key 1760 * is available to decrypt the session key. 1761 * 1762 * Returns Zero if a valid authentication token was retrieved and 1763 * processed; negative value for file not encrypted or for error 1764 * conditions. 1765 */ 1766 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 1767 unsigned char *src, 1768 struct dentry *ecryptfs_dentry) 1769 { 1770 size_t i = 0; 1771 size_t found_auth_tok; 1772 size_t next_packet_is_auth_tok_packet; 1773 struct list_head auth_tok_list; 1774 struct ecryptfs_auth_tok *matching_auth_tok; 1775 struct ecryptfs_auth_tok *candidate_auth_tok; 1776 char *candidate_auth_tok_sig; 1777 size_t packet_size; 1778 struct ecryptfs_auth_tok *new_auth_tok; 1779 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; 1780 struct ecryptfs_auth_tok_list_item *auth_tok_list_item; 1781 size_t tag_11_contents_size; 1782 size_t tag_11_packet_size; 1783 struct key *auth_tok_key = NULL; 1784 int rc = 0; 1785 1786 INIT_LIST_HEAD(&auth_tok_list); 1787 /* Parse the header to find as many packets as we can; these will be 1788 * added the our &auth_tok_list */ 1789 next_packet_is_auth_tok_packet = 1; 1790 while (next_packet_is_auth_tok_packet) { 1791 size_t max_packet_size = ((PAGE_SIZE - 8) - i); 1792 1793 switch (src[i]) { 1794 case ECRYPTFS_TAG_3_PACKET_TYPE: 1795 rc = parse_tag_3_packet(crypt_stat, 1796 (unsigned char *)&src[i], 1797 &auth_tok_list, &new_auth_tok, 1798 &packet_size, max_packet_size); 1799 if (rc) { 1800 ecryptfs_printk(KERN_ERR, "Error parsing " 1801 "tag 3 packet\n"); 1802 rc = -EIO; 1803 goto out_wipe_list; 1804 } 1805 i += packet_size; 1806 rc = parse_tag_11_packet((unsigned char *)&src[i], 1807 sig_tmp_space, 1808 ECRYPTFS_SIG_SIZE, 1809 &tag_11_contents_size, 1810 &tag_11_packet_size, 1811 max_packet_size); 1812 if (rc) { 1813 ecryptfs_printk(KERN_ERR, "No valid " 1814 "(ecryptfs-specific) literal " 1815 "packet containing " 1816 "authentication token " 1817 "signature found after " 1818 "tag 3 packet\n"); 1819 rc = -EIO; 1820 goto out_wipe_list; 1821 } 1822 i += tag_11_packet_size; 1823 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { 1824 ecryptfs_printk(KERN_ERR, "Expected " 1825 "signature of size [%d]; " 1826 "read size [%zd]\n", 1827 ECRYPTFS_SIG_SIZE, 1828 tag_11_contents_size); 1829 rc = -EIO; 1830 goto out_wipe_list; 1831 } 1832 ecryptfs_to_hex(new_auth_tok->token.password.signature, 1833 sig_tmp_space, tag_11_contents_size); 1834 new_auth_tok->token.password.signature[ 1835 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; 1836 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1837 break; 1838 case ECRYPTFS_TAG_1_PACKET_TYPE: 1839 rc = parse_tag_1_packet(crypt_stat, 1840 (unsigned char *)&src[i], 1841 &auth_tok_list, &new_auth_tok, 1842 &packet_size, max_packet_size); 1843 if (rc) { 1844 ecryptfs_printk(KERN_ERR, "Error parsing " 1845 "tag 1 packet\n"); 1846 rc = -EIO; 1847 goto out_wipe_list; 1848 } 1849 i += packet_size; 1850 crypt_stat->flags |= ECRYPTFS_ENCRYPTED; 1851 break; 1852 case ECRYPTFS_TAG_11_PACKET_TYPE: 1853 ecryptfs_printk(KERN_WARNING, "Invalid packet set " 1854 "(Tag 11 not allowed by itself)\n"); 1855 rc = -EIO; 1856 goto out_wipe_list; 1857 default: 1858 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " 1859 "of the file header; hex value of " 1860 "character is [0x%.2x]\n", i, src[i]); 1861 next_packet_is_auth_tok_packet = 0; 1862 } 1863 } 1864 if (list_empty(&auth_tok_list)) { 1865 printk(KERN_ERR "The lower file appears to be a non-encrypted " 1866 "eCryptfs file; this is not supported in this version " 1867 "of the eCryptfs kernel module\n"); 1868 rc = -EINVAL; 1869 goto out; 1870 } 1871 /* auth_tok_list contains the set of authentication tokens 1872 * parsed from the metadata. We need to find a matching 1873 * authentication token that has the secret component(s) 1874 * necessary to decrypt the EFEK in the auth_tok parsed from 1875 * the metadata. There may be several potential matches, but 1876 * just one will be sufficient to decrypt to get the FEK. */ 1877 find_next_matching_auth_tok: 1878 found_auth_tok = 0; 1879 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { 1880 candidate_auth_tok = &auth_tok_list_item->auth_tok; 1881 if (unlikely(ecryptfs_verbosity > 0)) { 1882 ecryptfs_printk(KERN_DEBUG, 1883 "Considering cadidate auth tok:\n"); 1884 ecryptfs_dump_auth_tok(candidate_auth_tok); 1885 } 1886 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, 1887 candidate_auth_tok); 1888 if (rc) { 1889 printk(KERN_ERR 1890 "Unrecognized candidate auth tok type: [%d]\n", 1891 candidate_auth_tok->token_type); 1892 rc = -EINVAL; 1893 goto out_wipe_list; 1894 } 1895 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, 1896 &matching_auth_tok, 1897 crypt_stat->mount_crypt_stat, 1898 candidate_auth_tok_sig); 1899 if (!rc) { 1900 found_auth_tok = 1; 1901 goto found_matching_auth_tok; 1902 } 1903 } 1904 if (!found_auth_tok) { 1905 ecryptfs_printk(KERN_ERR, "Could not find a usable " 1906 "authentication token\n"); 1907 rc = -EIO; 1908 goto out_wipe_list; 1909 } 1910 found_matching_auth_tok: 1911 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 1912 memcpy(&(candidate_auth_tok->token.private_key), 1913 &(matching_auth_tok->token.private_key), 1914 sizeof(struct ecryptfs_private_key)); 1915 up_write(&(auth_tok_key->sem)); 1916 key_put(auth_tok_key); 1917 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, 1918 crypt_stat); 1919 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { 1920 memcpy(&(candidate_auth_tok->token.password), 1921 &(matching_auth_tok->token.password), 1922 sizeof(struct ecryptfs_password)); 1923 up_write(&(auth_tok_key->sem)); 1924 key_put(auth_tok_key); 1925 rc = decrypt_passphrase_encrypted_session_key( 1926 candidate_auth_tok, crypt_stat); 1927 } else { 1928 up_write(&(auth_tok_key->sem)); 1929 key_put(auth_tok_key); 1930 rc = -EINVAL; 1931 } 1932 if (rc) { 1933 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; 1934 1935 ecryptfs_printk(KERN_WARNING, "Error decrypting the " 1936 "session key for authentication token with sig " 1937 "[%.*s]; rc = [%d]. Removing auth tok " 1938 "candidate from the list and searching for " 1939 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, 1940 candidate_auth_tok_sig, rc); 1941 list_for_each_entry_safe(auth_tok_list_item, 1942 auth_tok_list_item_tmp, 1943 &auth_tok_list, list) { 1944 if (candidate_auth_tok 1945 == &auth_tok_list_item->auth_tok) { 1946 list_del(&auth_tok_list_item->list); 1947 kmem_cache_free( 1948 ecryptfs_auth_tok_list_item_cache, 1949 auth_tok_list_item); 1950 goto find_next_matching_auth_tok; 1951 } 1952 } 1953 BUG(); 1954 } 1955 rc = ecryptfs_compute_root_iv(crypt_stat); 1956 if (rc) { 1957 ecryptfs_printk(KERN_ERR, "Error computing " 1958 "the root IV\n"); 1959 goto out_wipe_list; 1960 } 1961 rc = ecryptfs_init_crypt_ctx(crypt_stat); 1962 if (rc) { 1963 ecryptfs_printk(KERN_ERR, "Error initializing crypto " 1964 "context for cipher [%s]; rc = [%d]\n", 1965 crypt_stat->cipher, rc); 1966 } 1967 out_wipe_list: 1968 wipe_auth_tok_list(&auth_tok_list); 1969 out: 1970 return rc; 1971 } 1972 1973 static int 1974 pki_encrypt_session_key(struct key *auth_tok_key, 1975 struct ecryptfs_auth_tok *auth_tok, 1976 struct ecryptfs_crypt_stat *crypt_stat, 1977 struct ecryptfs_key_record *key_rec) 1978 { 1979 struct ecryptfs_msg_ctx *msg_ctx = NULL; 1980 char *payload = NULL; 1981 size_t payload_len = 0; 1982 struct ecryptfs_message *msg; 1983 int rc; 1984 1985 rc = write_tag_66_packet(auth_tok->token.private_key.signature, 1986 ecryptfs_code_for_cipher_string( 1987 crypt_stat->cipher, 1988 crypt_stat->key_size), 1989 crypt_stat, &payload, &payload_len); 1990 up_write(&(auth_tok_key->sem)); 1991 key_put(auth_tok_key); 1992 if (rc) { 1993 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); 1994 goto out; 1995 } 1996 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); 1997 if (rc) { 1998 ecryptfs_printk(KERN_ERR, "Error sending message to " 1999 "ecryptfsd: %d\n", rc); 2000 goto out; 2001 } 2002 rc = ecryptfs_wait_for_response(msg_ctx, &msg); 2003 if (rc) { 2004 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " 2005 "from the user space daemon\n"); 2006 rc = -EIO; 2007 goto out; 2008 } 2009 rc = parse_tag_67_packet(key_rec, msg); 2010 if (rc) 2011 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); 2012 kfree(msg); 2013 out: 2014 kfree(payload); 2015 return rc; 2016 } 2017 /** 2018 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet 2019 * @dest: Buffer into which to write the packet 2020 * @remaining_bytes: Maximum number of bytes that can be writtn 2021 * @auth_tok_key: The authentication token key to unlock and put when done with 2022 * @auth_tok 2023 * @auth_tok: The authentication token used for generating the tag 1 packet 2024 * @crypt_stat: The cryptographic context 2025 * @key_rec: The key record struct for the tag 1 packet 2026 * @packet_size: This function will write the number of bytes that end 2027 * up constituting the packet; set to zero on error 2028 * 2029 * Returns zero on success; non-zero on error. 2030 */ 2031 static int 2032 write_tag_1_packet(char *dest, size_t *remaining_bytes, 2033 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, 2034 struct ecryptfs_crypt_stat *crypt_stat, 2035 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2036 { 2037 size_t i; 2038 size_t encrypted_session_key_valid = 0; 2039 size_t packet_size_length; 2040 size_t max_packet_size; 2041 int rc = 0; 2042 2043 (*packet_size) = 0; 2044 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, 2045 ECRYPTFS_SIG_SIZE); 2046 encrypted_session_key_valid = 0; 2047 for (i = 0; i < crypt_stat->key_size; i++) 2048 encrypted_session_key_valid |= 2049 auth_tok->session_key.encrypted_key[i]; 2050 if (encrypted_session_key_valid) { 2051 memcpy(key_rec->enc_key, 2052 auth_tok->session_key.encrypted_key, 2053 auth_tok->session_key.encrypted_key_size); 2054 up_write(&(auth_tok_key->sem)); 2055 key_put(auth_tok_key); 2056 goto encrypted_session_key_set; 2057 } 2058 if (auth_tok->session_key.encrypted_key_size == 0) 2059 auth_tok->session_key.encrypted_key_size = 2060 auth_tok->token.private_key.key_size; 2061 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, 2062 key_rec); 2063 if (rc) { 2064 printk(KERN_ERR "Failed to encrypt session key via a key " 2065 "module; rc = [%d]\n", rc); 2066 goto out; 2067 } 2068 if (ecryptfs_verbosity > 0) { 2069 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); 2070 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); 2071 } 2072 encrypted_session_key_set: 2073 /* This format is inspired by OpenPGP; see RFC 2440 2074 * packet tag 1 */ 2075 max_packet_size = (1 /* Tag 1 identifier */ 2076 + 3 /* Max Tag 1 packet size */ 2077 + 1 /* Version */ 2078 + ECRYPTFS_SIG_SIZE /* Key identifier */ 2079 + 1 /* Cipher identifier */ 2080 + key_rec->enc_key_size); /* Encrypted key size */ 2081 if (max_packet_size > (*remaining_bytes)) { 2082 printk(KERN_ERR "Packet length larger than maximum allowable; " 2083 "need up to [%td] bytes, but there are only [%td] " 2084 "available\n", max_packet_size, (*remaining_bytes)); 2085 rc = -EINVAL; 2086 goto out; 2087 } 2088 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; 2089 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2090 (max_packet_size - 4), 2091 &packet_size_length); 2092 if (rc) { 2093 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " 2094 "header; cannot generate packet length\n"); 2095 goto out; 2096 } 2097 (*packet_size) += packet_size_length; 2098 dest[(*packet_size)++] = 0x03; /* version 3 */ 2099 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); 2100 (*packet_size) += ECRYPTFS_SIG_SIZE; 2101 dest[(*packet_size)++] = RFC2440_CIPHER_RSA; 2102 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2103 key_rec->enc_key_size); 2104 (*packet_size) += key_rec->enc_key_size; 2105 out: 2106 if (rc) 2107 (*packet_size) = 0; 2108 else 2109 (*remaining_bytes) -= (*packet_size); 2110 return rc; 2111 } 2112 2113 /** 2114 * write_tag_11_packet 2115 * @dest: Target into which Tag 11 packet is to be written 2116 * @remaining_bytes: Maximum packet length 2117 * @contents: Byte array of contents to copy in 2118 * @contents_length: Number of bytes in contents 2119 * @packet_length: Length of the Tag 11 packet written; zero on error 2120 * 2121 * Returns zero on success; non-zero on error. 2122 */ 2123 static int 2124 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, 2125 size_t contents_length, size_t *packet_length) 2126 { 2127 size_t packet_size_length; 2128 size_t max_packet_size; 2129 int rc = 0; 2130 2131 (*packet_length) = 0; 2132 /* This format is inspired by OpenPGP; see RFC 2440 2133 * packet tag 11 */ 2134 max_packet_size = (1 /* Tag 11 identifier */ 2135 + 3 /* Max Tag 11 packet size */ 2136 + 1 /* Binary format specifier */ 2137 + 1 /* Filename length */ 2138 + 8 /* Filename ("_CONSOLE") */ 2139 + 4 /* Modification date */ 2140 + contents_length); /* Literal data */ 2141 if (max_packet_size > (*remaining_bytes)) { 2142 printk(KERN_ERR "Packet length larger than maximum allowable; " 2143 "need up to [%td] bytes, but there are only [%td] " 2144 "available\n", max_packet_size, (*remaining_bytes)); 2145 rc = -EINVAL; 2146 goto out; 2147 } 2148 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; 2149 rc = ecryptfs_write_packet_length(&dest[(*packet_length)], 2150 (max_packet_size - 4), 2151 &packet_size_length); 2152 if (rc) { 2153 printk(KERN_ERR "Error generating tag 11 packet header; cannot " 2154 "generate packet length. rc = [%d]\n", rc); 2155 goto out; 2156 } 2157 (*packet_length) += packet_size_length; 2158 dest[(*packet_length)++] = 0x62; /* binary data format specifier */ 2159 dest[(*packet_length)++] = 8; 2160 memcpy(&dest[(*packet_length)], "_CONSOLE", 8); 2161 (*packet_length) += 8; 2162 memset(&dest[(*packet_length)], 0x00, 4); 2163 (*packet_length) += 4; 2164 memcpy(&dest[(*packet_length)], contents, contents_length); 2165 (*packet_length) += contents_length; 2166 out: 2167 if (rc) 2168 (*packet_length) = 0; 2169 else 2170 (*remaining_bytes) -= (*packet_length); 2171 return rc; 2172 } 2173 2174 /** 2175 * write_tag_3_packet 2176 * @dest: Buffer into which to write the packet 2177 * @remaining_bytes: Maximum number of bytes that can be written 2178 * @auth_tok: Authentication token 2179 * @crypt_stat: The cryptographic context 2180 * @key_rec: encrypted key 2181 * @packet_size: This function will write the number of bytes that end 2182 * up constituting the packet; set to zero on error 2183 * 2184 * Returns zero on success; non-zero on error. 2185 */ 2186 static int 2187 write_tag_3_packet(char *dest, size_t *remaining_bytes, 2188 struct ecryptfs_auth_tok *auth_tok, 2189 struct ecryptfs_crypt_stat *crypt_stat, 2190 struct ecryptfs_key_record *key_rec, size_t *packet_size) 2191 { 2192 size_t i; 2193 size_t encrypted_session_key_valid = 0; 2194 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 2195 struct scatterlist dst_sg[2]; 2196 struct scatterlist src_sg[2]; 2197 struct mutex *tfm_mutex = NULL; 2198 u8 cipher_code; 2199 size_t packet_size_length; 2200 size_t max_packet_size; 2201 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2202 crypt_stat->mount_crypt_stat; 2203 struct crypto_skcipher *tfm; 2204 struct skcipher_request *req; 2205 int rc = 0; 2206 2207 (*packet_size) = 0; 2208 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, 2209 ECRYPTFS_SIG_SIZE); 2210 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, 2211 crypt_stat->cipher); 2212 if (unlikely(rc)) { 2213 printk(KERN_ERR "Internal error whilst attempting to get " 2214 "tfm and mutex for cipher name [%s]; rc = [%d]\n", 2215 crypt_stat->cipher, rc); 2216 goto out; 2217 } 2218 if (mount_crypt_stat->global_default_cipher_key_size == 0) { 2219 printk(KERN_WARNING "No key size specified at mount; " 2220 "defaulting to [%d]\n", 2221 crypto_skcipher_default_keysize(tfm)); 2222 mount_crypt_stat->global_default_cipher_key_size = 2223 crypto_skcipher_default_keysize(tfm); 2224 } 2225 if (crypt_stat->key_size == 0) 2226 crypt_stat->key_size = 2227 mount_crypt_stat->global_default_cipher_key_size; 2228 if (auth_tok->session_key.encrypted_key_size == 0) 2229 auth_tok->session_key.encrypted_key_size = 2230 crypt_stat->key_size; 2231 if (crypt_stat->key_size == 24 2232 && strcmp("aes", crypt_stat->cipher) == 0) { 2233 memset((crypt_stat->key + 24), 0, 8); 2234 auth_tok->session_key.encrypted_key_size = 32; 2235 } else 2236 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; 2237 key_rec->enc_key_size = 2238 auth_tok->session_key.encrypted_key_size; 2239 encrypted_session_key_valid = 0; 2240 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) 2241 encrypted_session_key_valid |= 2242 auth_tok->session_key.encrypted_key[i]; 2243 if (encrypted_session_key_valid) { 2244 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " 2245 "using auth_tok->session_key.encrypted_key, " 2246 "where key_rec->enc_key_size = [%zd]\n", 2247 key_rec->enc_key_size); 2248 memcpy(key_rec->enc_key, 2249 auth_tok->session_key.encrypted_key, 2250 key_rec->enc_key_size); 2251 goto encrypted_session_key_set; 2252 } 2253 if (auth_tok->token.password.flags & 2254 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { 2255 ecryptfs_printk(KERN_DEBUG, "Using previously generated " 2256 "session key encryption key of size [%d]\n", 2257 auth_tok->token.password. 2258 session_key_encryption_key_bytes); 2259 memcpy(session_key_encryption_key, 2260 auth_tok->token.password.session_key_encryption_key, 2261 crypt_stat->key_size); 2262 ecryptfs_printk(KERN_DEBUG, 2263 "Cached session key encryption key:\n"); 2264 if (ecryptfs_verbosity > 0) 2265 ecryptfs_dump_hex(session_key_encryption_key, 16); 2266 } 2267 if (unlikely(ecryptfs_verbosity > 0)) { 2268 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); 2269 ecryptfs_dump_hex(session_key_encryption_key, 16); 2270 } 2271 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, 2272 src_sg, 2); 2273 if (rc < 1 || rc > 2) { 2274 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2275 "for crypt_stat session key; expected rc = 1; " 2276 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", 2277 rc, key_rec->enc_key_size); 2278 rc = -ENOMEM; 2279 goto out; 2280 } 2281 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, 2282 dst_sg, 2); 2283 if (rc < 1 || rc > 2) { 2284 ecryptfs_printk(KERN_ERR, "Error generating scatterlist " 2285 "for crypt_stat encrypted session key; " 2286 "expected rc = 1; got rc = [%d]. " 2287 "key_rec->enc_key_size = [%zd]\n", rc, 2288 key_rec->enc_key_size); 2289 rc = -ENOMEM; 2290 goto out; 2291 } 2292 mutex_lock(tfm_mutex); 2293 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key, 2294 crypt_stat->key_size); 2295 if (rc < 0) { 2296 mutex_unlock(tfm_mutex); 2297 ecryptfs_printk(KERN_ERR, "Error setting key for crypto " 2298 "context; rc = [%d]\n", rc); 2299 goto out; 2300 } 2301 2302 req = skcipher_request_alloc(tfm, GFP_KERNEL); 2303 if (!req) { 2304 mutex_unlock(tfm_mutex); 2305 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " 2306 "attempting to skcipher_request_alloc for " 2307 "%s\n", crypto_skcipher_driver_name(tfm)); 2308 rc = -ENOMEM; 2309 goto out; 2310 } 2311 2312 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, 2313 NULL, NULL); 2314 2315 rc = 0; 2316 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", 2317 crypt_stat->key_size); 2318 skcipher_request_set_crypt(req, src_sg, dst_sg, 2319 (*key_rec).enc_key_size, NULL); 2320 rc = crypto_skcipher_encrypt(req); 2321 mutex_unlock(tfm_mutex); 2322 skcipher_request_free(req); 2323 if (rc) { 2324 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); 2325 goto out; 2326 } 2327 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); 2328 if (ecryptfs_verbosity > 0) { 2329 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", 2330 key_rec->enc_key_size); 2331 ecryptfs_dump_hex(key_rec->enc_key, 2332 key_rec->enc_key_size); 2333 } 2334 encrypted_session_key_set: 2335 /* This format is inspired by OpenPGP; see RFC 2440 2336 * packet tag 3 */ 2337 max_packet_size = (1 /* Tag 3 identifier */ 2338 + 3 /* Max Tag 3 packet size */ 2339 + 1 /* Version */ 2340 + 1 /* Cipher code */ 2341 + 1 /* S2K specifier */ 2342 + 1 /* Hash identifier */ 2343 + ECRYPTFS_SALT_SIZE /* Salt */ 2344 + 1 /* Hash iterations */ 2345 + key_rec->enc_key_size); /* Encrypted key size */ 2346 if (max_packet_size > (*remaining_bytes)) { 2347 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " 2348 "there are only [%td] available\n", max_packet_size, 2349 (*remaining_bytes)); 2350 rc = -EINVAL; 2351 goto out; 2352 } 2353 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; 2354 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) 2355 * to get the number of octets in the actual Tag 3 packet */ 2356 rc = ecryptfs_write_packet_length(&dest[(*packet_size)], 2357 (max_packet_size - 4), 2358 &packet_size_length); 2359 if (rc) { 2360 printk(KERN_ERR "Error generating tag 3 packet header; cannot " 2361 "generate packet length. rc = [%d]\n", rc); 2362 goto out; 2363 } 2364 (*packet_size) += packet_size_length; 2365 dest[(*packet_size)++] = 0x04; /* version 4 */ 2366 /* TODO: Break from RFC2440 so that arbitrary ciphers can be 2367 * specified with strings */ 2368 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, 2369 crypt_stat->key_size); 2370 if (cipher_code == 0) { 2371 ecryptfs_printk(KERN_WARNING, "Unable to generate code for " 2372 "cipher [%s]\n", crypt_stat->cipher); 2373 rc = -EINVAL; 2374 goto out; 2375 } 2376 dest[(*packet_size)++] = cipher_code; 2377 dest[(*packet_size)++] = 0x03; /* S2K */ 2378 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ 2379 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, 2380 ECRYPTFS_SALT_SIZE); 2381 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ 2382 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ 2383 memcpy(&dest[(*packet_size)], key_rec->enc_key, 2384 key_rec->enc_key_size); 2385 (*packet_size) += key_rec->enc_key_size; 2386 out: 2387 if (rc) 2388 (*packet_size) = 0; 2389 else 2390 (*remaining_bytes) -= (*packet_size); 2391 return rc; 2392 } 2393 2394 struct kmem_cache *ecryptfs_key_record_cache; 2395 2396 /** 2397 * ecryptfs_generate_key_packet_set 2398 * @dest_base: Virtual address from which to write the key record set 2399 * @crypt_stat: The cryptographic context from which the 2400 * authentication tokens will be retrieved 2401 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat 2402 * for the global parameters 2403 * @len: The amount written 2404 * @max: The maximum amount of data allowed to be written 2405 * 2406 * Generates a key packet set and writes it to the virtual address 2407 * passed in. 2408 * 2409 * Returns zero on success; non-zero on error. 2410 */ 2411 int 2412 ecryptfs_generate_key_packet_set(char *dest_base, 2413 struct ecryptfs_crypt_stat *crypt_stat, 2414 struct dentry *ecryptfs_dentry, size_t *len, 2415 size_t max) 2416 { 2417 struct ecryptfs_auth_tok *auth_tok; 2418 struct key *auth_tok_key = NULL; 2419 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 2420 &ecryptfs_superblock_to_private( 2421 ecryptfs_dentry->d_sb)->mount_crypt_stat; 2422 size_t written; 2423 struct ecryptfs_key_record *key_rec; 2424 struct ecryptfs_key_sig *key_sig; 2425 int rc = 0; 2426 2427 (*len) = 0; 2428 mutex_lock(&crypt_stat->keysig_list_mutex); 2429 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); 2430 if (!key_rec) { 2431 rc = -ENOMEM; 2432 goto out; 2433 } 2434 list_for_each_entry(key_sig, &crypt_stat->keysig_list, 2435 crypt_stat_list) { 2436 memset(key_rec, 0, sizeof(*key_rec)); 2437 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, 2438 &auth_tok, 2439 mount_crypt_stat, 2440 key_sig->keysig); 2441 if (rc) { 2442 printk(KERN_WARNING "Unable to retrieve auth tok with " 2443 "sig = [%s]\n", key_sig->keysig); 2444 rc = process_find_global_auth_tok_for_sig_err(rc); 2445 goto out_free; 2446 } 2447 if (auth_tok->token_type == ECRYPTFS_PASSWORD) { 2448 rc = write_tag_3_packet((dest_base + (*len)), 2449 &max, auth_tok, 2450 crypt_stat, key_rec, 2451 &written); 2452 up_write(&(auth_tok_key->sem)); 2453 key_put(auth_tok_key); 2454 if (rc) { 2455 ecryptfs_printk(KERN_WARNING, "Error " 2456 "writing tag 3 packet\n"); 2457 goto out_free; 2458 } 2459 (*len) += written; 2460 /* Write auth tok signature packet */ 2461 rc = write_tag_11_packet((dest_base + (*len)), &max, 2462 key_rec->sig, 2463 ECRYPTFS_SIG_SIZE, &written); 2464 if (rc) { 2465 ecryptfs_printk(KERN_ERR, "Error writing " 2466 "auth tok signature packet\n"); 2467 goto out_free; 2468 } 2469 (*len) += written; 2470 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { 2471 rc = write_tag_1_packet(dest_base + (*len), &max, 2472 auth_tok_key, auth_tok, 2473 crypt_stat, key_rec, &written); 2474 if (rc) { 2475 ecryptfs_printk(KERN_WARNING, "Error " 2476 "writing tag 1 packet\n"); 2477 goto out_free; 2478 } 2479 (*len) += written; 2480 } else { 2481 up_write(&(auth_tok_key->sem)); 2482 key_put(auth_tok_key); 2483 ecryptfs_printk(KERN_WARNING, "Unsupported " 2484 "authentication token type\n"); 2485 rc = -EINVAL; 2486 goto out_free; 2487 } 2488 } 2489 if (likely(max > 0)) { 2490 dest_base[(*len)] = 0x00; 2491 } else { 2492 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); 2493 rc = -EIO; 2494 } 2495 out_free: 2496 kmem_cache_free(ecryptfs_key_record_cache, key_rec); 2497 out: 2498 if (rc) 2499 (*len) = 0; 2500 mutex_unlock(&crypt_stat->keysig_list_mutex); 2501 return rc; 2502 } 2503 2504 struct kmem_cache *ecryptfs_key_sig_cache; 2505 2506 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) 2507 { 2508 struct ecryptfs_key_sig *new_key_sig; 2509 2510 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); 2511 if (!new_key_sig) 2512 return -ENOMEM; 2513 2514 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); 2515 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2516 /* Caller must hold keysig_list_mutex */ 2517 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); 2518 2519 return 0; 2520 } 2521 2522 struct kmem_cache *ecryptfs_global_auth_tok_cache; 2523 2524 int 2525 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, 2526 char *sig, u32 global_auth_tok_flags) 2527 { 2528 struct ecryptfs_global_auth_tok *new_auth_tok; 2529 2530 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, 2531 GFP_KERNEL); 2532 if (!new_auth_tok) 2533 return -ENOMEM; 2534 2535 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); 2536 new_auth_tok->flags = global_auth_tok_flags; 2537 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; 2538 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); 2539 list_add(&new_auth_tok->mount_crypt_stat_list, 2540 &mount_crypt_stat->global_auth_tok_list); 2541 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); 2542 return 0; 2543 } 2544 2545