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