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