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