fs/ecryptfs/keystore.c

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