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 <[email protected]>
   9  *              Michael C. Thompson <[email protected]>
  10  *              Trevor S. Highland <[email protected]>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  25  * 02111-1307, USA.
  26  */
  27
  28 #include <crypto/hash.h>
  29 #include <crypto/skcipher.h>
  30 #include <linux/string.h>
  31 #include <linux/pagemap.h>
  32 #include <linux/key.h>
  33 #include <linux/random.h>
  34 #include <linux/scatterlist.h>
  35 #include <linux/slab.h>
  36 #include "ecryptfs_kernel.h"
  37
  38 /**
  39  * request_key returned an error instead of a valid key address;
  40  * determine the type of error, make appropriate log entries, and
  41  * return an error code.
  42  */
  43 static int process_request_key_err(long err_code)
  44 {
  45         int rc = 0;
  46
  47         switch (err_code) {
  48         case -ENOKEY:
  49                 ecryptfs_printk(KERN_WARNING, "No key\n");
  50                 rc = -ENOENT;
  51                 break;
  52         case -EKEYEXPIRED:
  53                 ecryptfs_printk(KERN_WARNING, "Key expired\n");
  54                 rc = -ETIME;
  55                 break;
  56         case -EKEYREVOKED:
  57                 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
  58                 rc = -EINVAL;
  59                 break;
  60         default:
  61                 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
  62                                 "[0x%.16lx]\n", err_code);
  63                 rc = -EINVAL;
  64         }
  65         return rc;
  66 }
  67
  68 static int process_find_global_auth_tok_for_sig_err(int err_code)
  69 {
  70         int rc = err_code;
  71
  72         switch (err_code) {
  73         case -ENOENT:
  74                 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
  75                 break;
  76         case -EINVAL:
  77                 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
  78                 break;
  79         default:
  80                 rc = process_request_key_err(err_code);
  81                 break;
  82         }
  83         return rc;
  84 }
  85
  86 /**
  87  * ecryptfs_parse_packet_length
  88  * @data: Pointer to memory containing length at offset
  89  * @size: This function writes the decoded size to this memory
  90  *        address; zero on error
  91  * @length_size: The number of bytes occupied by the encoded length
  92  *
  93  * Returns zero on success; non-zero on error
  94  */
  95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
  96                                  size_t *length_size)
  97 {
  98         int rc = 0;
  99
 100         (*length_size) = 0;
 101         (*size) = 0;
 102         if (data[0] < 192) {
 103                 /* One-byte length */
 104                 (*size) = data[0];
 105                 (*length_size) = 1;
 106         } else if (data[0] < 224) {
 107                 /* Two-byte length */
 108                 (*size) = (data[0] - 192) * 256;
 109                 (*size) += data[1] + 192;
 110                 (*length_size) = 2;
 111         } else if (data[0] == 255) {
 112                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
 113                 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
 114                                 "supported\n");
 115                 rc = -EINVAL;
 116                 goto out;
 117         } else {
 118                 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
 119                 rc = -EINVAL;
 120                 goto out;
 121         }
 122 out:
 123         return rc;
 124 }
 125
 126 /**
 127  * ecryptfs_write_packet_length
 128  * @dest: The byte array target into which to write the length. Must
 129  *        have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
 130  * @size: The length to write.
 131  * @packet_size_length: The number of bytes used to encode the packet
 132  *                      length is written to this address.
 133  *
 134  * Returns zero on success; non-zero on error.
 135  */
 136 int ecryptfs_write_packet_length(char *dest, size_t size,
 137                                  size_t *packet_size_length)
 138 {
 139         int rc = 0;
 140
 141         if (size < 192) {
 142                 dest[0] = size;
 143                 (*packet_size_length) = 1;
 144         } else if (size < 65536) {
 145                 dest[0] = (((size - 192) / 256) + 192);
 146                 dest[1] = ((size - 192) % 256);
 147                 (*packet_size_length) = 2;
 148         } else {
 149                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
 150                 rc = -EINVAL;
 151                 ecryptfs_printk(KERN_WARNING,
 152                                 "Unsupported packet size: [%zd]\n", size);
 153         }
 154         return rc;
 155 }
 156
 157 static int
 158 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
 159                     char **packet, size_t *packet_len)
 160 {
 161         size_t i = 0;
 162         size_t data_len;
 163         size_t packet_size_len;
 164         char *message;
 165         int rc;
 166
 167         /*
 168          *              ***** TAG 64 Packet Format *****
 169          *    | Content Type                       | 1 byte       |
 170          *    | Key Identifier Size                | 1 or 2 bytes |
 171          *    | Key Identifier                     | arbitrary    |
 172          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 173          *    | Encrypted File Encryption Key      | arbitrary    |
 174          */
 175         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
 176                     + session_key->encrypted_key_size);
 177         *packet = kmalloc(data_len, GFP_KERNEL);
 178         message = *packet;
 179         if (!message) {
 180                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 181                 rc = -ENOMEM;
 182                 goto out;
 183         }
 184         message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
 185         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 186                                           &packet_size_len);
 187         if (rc) {
 188                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 189                                 "header; cannot generate packet length\n");
 190                 goto out;
 191         }
 192         i += packet_size_len;
 193         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 194         i += ECRYPTFS_SIG_SIZE_HEX;
 195         rc = ecryptfs_write_packet_length(&message[i],
 196                                           session_key->encrypted_key_size,
 197                                           &packet_size_len);
 198         if (rc) {
 199                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 200                                 "header; cannot generate packet length\n");
 201                 goto out;
 202         }
 203         i += packet_size_len;
 204         memcpy(&message[i], session_key->encrypted_key,
 205                session_key->encrypted_key_size);
 206         i += session_key->encrypted_key_size;
 207         *packet_len = i;
 208 out:
 209         return rc;
 210 }
 211
 212 static int
 213 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
 214                     struct ecryptfs_message *msg)
 215 {
 216         size_t i = 0;
 217         char *data;
 218         size_t data_len;
 219         size_t m_size;
 220         size_t message_len;
 221         u16 checksum = 0;
 222         u16 expected_checksum = 0;
 223         int rc;
 224
 225         /*
 226          *              ***** TAG 65 Packet Format *****
 227          *         | Content Type             | 1 byte       |
 228          *         | Status Indicator         | 1 byte       |
 229          *         | File Encryption Key Size | 1 or 2 bytes |
 230          *         | File Encryption Key      | arbitrary    |
 231          */
 232         message_len = msg->data_len;
 233         data = msg->data;
 234         if (message_len < 4) {
 235                 rc = -EIO;
 236                 goto out;
 237         }
 238         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
 239                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
 240                 rc = -EIO;
 241                 goto out;
 242         }
 243         if (data[i++]) {
 244                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
 245                                 "[%d]\n", data[i-1]);
 246                 rc = -EIO;
 247                 goto out;
 248         }
 249         rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
 250         if (rc) {
 251                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 252                                 "rc = [%d]\n", rc);
 253                 goto out;
 254         }
 255         i += data_len;
 256         if (message_len < (i + m_size)) {
 257                 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
 258                                 "is shorter than expected\n");
 259                 rc = -EIO;
 260                 goto out;
 261         }
 262         if (m_size < 3) {
 263                 ecryptfs_printk(KERN_ERR,
 264                                 "The decrypted key is not long enough to "
 265                                 "include a cipher code and checksum\n");
 266                 rc = -EIO;
 267                 goto out;
 268         }
 269         *cipher_code = data[i++];
 270         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
 271         session_key->decrypted_key_size = m_size - 3;
 272         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
 273                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
 274                                 "the maximum key size [%d]\n",
 275                                 session_key->decrypted_key_size,
 276                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 277                 rc = -EIO;
 278                 goto out;
 279         }
 280         memcpy(session_key->decrypted_key, &data[i],
 281                session_key->decrypted_key_size);
 282         i += session_key->decrypted_key_size;
 283         expected_checksum += (unsigned char)(data[i++]) << 8;
 284         expected_checksum += (unsigned char)(data[i++]);
 285         for (i = 0; i < session_key->decrypted_key_size; i++)
 286                 checksum += session_key->decrypted_key[i];
 287         if (expected_checksum != checksum) {
 288                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
 289                                 "encryption  key; expected [%x]; calculated "
 290                                 "[%x]\n", expected_checksum, checksum);
 291                 rc = -EIO;
 292         }
 293 out:
 294         return rc;
 295 }
 296
 297
 298 static int
 299 write_tag_66_packet(char *signature, u8 cipher_code,
 300                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
 301                     size_t *packet_len)
 302 {
 303         size_t i = 0;
 304         size_t j;
 305         size_t data_len;
 306         size_t checksum = 0;
 307         size_t packet_size_len;
 308         char *message;
 309         int rc;
 310
 311         /*
 312          *              ***** TAG 66 Packet Format *****
 313          *         | Content Type             | 1 byte       |
 314          *         | Key Identifier Size      | 1 or 2 bytes |
 315          *         | Key Identifier           | arbitrary    |
 316          *         | File Encryption Key Size | 1 or 2 bytes |
 317          *         | File Encryption Key      | arbitrary    |
 318          */
 319         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
 320         *packet = kmalloc(data_len, GFP_KERNEL);
 321         message = *packet;
 322         if (!message) {
 323                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 324                 rc = -ENOMEM;
 325                 goto out;
 326         }
 327         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
 328         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 329                                           &packet_size_len);
 330         if (rc) {
 331                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 332                                 "header; cannot generate packet length\n");
 333                 goto out;
 334         }
 335         i += packet_size_len;
 336         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 337         i += ECRYPTFS_SIG_SIZE_HEX;
 338         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
 339         rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
 340                                           &packet_size_len);
 341         if (rc) {
 342                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 343                                 "header; cannot generate packet length\n");
 344                 goto out;
 345         }
 346         i += packet_size_len;
 347         message[i++] = cipher_code;
 348         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
 349         i += crypt_stat->key_size;
 350         for (j = 0; j < crypt_stat->key_size; j++)
 351                 checksum += crypt_stat->key[j];
 352         message[i++] = (checksum / 256) % 256;
 353         message[i++] = (checksum % 256);
 354         *packet_len = i;
 355 out:
 356         return rc;
 357 }
 358
 359 static int
 360 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
 361                     struct ecryptfs_message *msg)
 362 {
 363         size_t i = 0;
 364         char *data;
 365         size_t data_len;
 366         size_t message_len;
 367         int rc;
 368
 369         /*
 370          *              ***** TAG 65 Packet Format *****
 371          *    | Content Type                       | 1 byte       |
 372          *    | Status Indicator                   | 1 byte       |
 373          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 374          *    | Encrypted File Encryption Key      | arbitrary    |
 375          */
 376         message_len = msg->data_len;
 377         data = msg->data;
 378         /* verify that everything through the encrypted FEK size is present */
 379         if (message_len < 4) {
 380                 rc = -EIO;
 381                 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
 382                        "message length is [%d]\n", __func__, message_len, 4);
 383                 goto out;
 384         }
 385         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
 386                 rc = -EIO;
 387                 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
 388                        __func__);
 389                 goto out;
 390         }
 391         if (data[i++]) {
 392                 rc = -EIO;
 393                 printk(KERN_ERR "%s: Status indicator has non zero "
 394                        "value [%d]\n", __func__, data[i-1]);
 395
 396                 goto out;
 397         }
 398         rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
 399                                           &data_len);
 400         if (rc) {
 401                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 402                                 "rc = [%d]\n", rc);
 403                 goto out;
 404         }
 405         i += data_len;
 406         if (message_len < (i + key_rec->enc_key_size)) {
 407                 rc = -EIO;
 408                 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
 409                        __func__, message_len, (i + key_rec->enc_key_size));
 410                 goto out;
 411         }
 412         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 413                 rc = -EIO;
 414                 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
 415                        "the maximum key size [%d]\n", __func__,
 416                        key_rec->enc_key_size,
 417                        ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 418                 goto out;
 419         }
 420         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
 421 out:
 422         return rc;
 423 }
 424
 425 /**
 426  * ecryptfs_verify_version
 427  * @version: The version number to confirm
 428  *
 429  * Returns zero on good version; non-zero otherwise
 430  */
 431 static int ecryptfs_verify_version(u16 version)
 432 {
 433         int rc = 0;
 434         unsigned char major;
 435         unsigned char minor;
 436
 437         major = ((version >> 8) & 0xFF);
 438         minor = (version & 0xFF);
 439         if (major != ECRYPTFS_VERSION_MAJOR) {
 440                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 441                                 "Expected [%d]; got [%d]\n",
 442                                 ECRYPTFS_VERSION_MAJOR, major);
 443                 rc = -EINVAL;
 444                 goto out;
 445         }
 446         if (minor != ECRYPTFS_VERSION_MINOR) {
 447                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 448                                 "Expected [%d]; got [%d]\n",
 449                                 ECRYPTFS_VERSION_MINOR, minor);
 450                 rc = -EINVAL;
 451                 goto out;
 452         }
 453 out:
 454         return rc;
 455 }
 456
 457 /**
 458  * ecryptfs_verify_auth_tok_from_key
 459  * @auth_tok_key: key containing the authentication token
 460  * @auth_tok: authentication token
 461  *
 462  * Returns zero on valid auth tok; -EINVAL otherwise
 463  */
 464 static int
 465 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
 466                                   struct ecryptfs_auth_tok **auth_tok)
 467 {
 468         int rc = 0;
 469
 470         (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
 471         if (ecryptfs_verify_version((*auth_tok)->version)) {
 472                 printk(KERN_ERR "Data structure version mismatch. Userspace "
 473                        "tools must match eCryptfs kernel module with major "
 474                        "version [%d] and minor version [%d]\n",
 475                        ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
 476                 rc = -EINVAL;
 477                 goto out;
 478         }
 479         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
 480             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
 481                 printk(KERN_ERR "Invalid auth_tok structure "
 482                        "returned from key query\n");
 483                 rc = -EINVAL;
 484                 goto out;
 485         }
 486 out:
 487         return rc;
 488 }
 489
 490 static int
 491 ecryptfs_find_global_auth_tok_for_sig(
 492         struct key **auth_tok_key,
 493         struct ecryptfs_auth_tok **auth_tok,
 494         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 495 {
 496         struct ecryptfs_global_auth_tok *walker;
 497         int rc = 0;
 498
 499         (*auth_tok_key) = NULL;
 500         (*auth_tok) = NULL;
 501         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 502         list_for_each_entry(walker,
 503                             &mount_crypt_stat->global_auth_tok_list,
 504                             mount_crypt_stat_list) {
 505                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
 506                         continue;
 507
 508                 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
 509                         rc = -EINVAL;
 510                         goto out;
 511                 }
 512
 513                 rc = key_validate(walker->global_auth_tok_key);
 514                 if (rc) {
 515                         if (rc == -EKEYEXPIRED)
 516                                 goto out;
 517                         goto out_invalid_auth_tok;
 518                 }
 519
 520                 down_write(&(walker->global_auth_tok_key->sem));
 521                 rc = ecryptfs_verify_auth_tok_from_key(
 522                                 walker->global_auth_tok_key, auth_tok);
 523                 if (rc)
 524                         goto out_invalid_auth_tok_unlock;
 525
 526                 (*auth_tok_key) = walker->global_auth_tok_key;
 527                 key_get(*auth_tok_key);
 528                 goto out;
 529         }
 530         rc = -ENOENT;
 531         goto out;
 532 out_invalid_auth_tok_unlock:
 533         up_write(&(walker->global_auth_tok_key->sem));
 534 out_invalid_auth_tok:
 535         printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
 536         walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 537         key_put(walker->global_auth_tok_key);
 538         walker->global_auth_tok_key = NULL;
 539 out:
 540         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 541         return rc;
 542 }
 543
 544 /**
 545  * ecryptfs_find_auth_tok_for_sig
 546  * @auth_tok: Set to the matching auth_tok; NULL if not found
 547  * @crypt_stat: inode crypt_stat crypto context
 548  * @sig: Sig of auth_tok to find
 549  *
 550  * For now, this function simply looks at the registered auth_tok's
 551  * linked off the mount_crypt_stat, so all the auth_toks that can be
 552  * used must be registered at mount time. This function could
 553  * potentially try a lot harder to find auth_tok's (e.g., by calling
 554  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
 555  * that static registration of auth_tok's will no longer be necessary.
 556  *
 557  * Returns zero on no error; non-zero on error
 558  */
 559 static int
 560 ecryptfs_find_auth_tok_for_sig(
 561         struct key **auth_tok_key,
 562         struct ecryptfs_auth_tok **auth_tok,
 563         struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 564         char *sig)
 565 {
 566         int rc = 0;
 567
 568         rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
 569                                                    mount_crypt_stat, sig);
 570         if (rc == -ENOENT) {
 571                 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
 572                  * mount_crypt_stat structure, we prevent to use auth toks that
 573                  * are not inserted through the ecryptfs_add_global_auth_tok
 574                  * function.
 575                  */
 576                 if (mount_crypt_stat->flags
 577                                 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
 578                         return -EINVAL;
 579
 580                 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
 581                                                        sig);
 582         }
 583         return rc;
 584 }
 585
 586 /**
 587  * write_tag_70_packet can gobble a lot of stack space. We stuff most
 588  * of the function's parameters in a kmalloc'd struct to help reduce
 589  * eCryptfs' overall stack usage.
 590  */
 591 struct ecryptfs_write_tag_70_packet_silly_stack {
 592         u8 cipher_code;
 593         size_t max_packet_size;
 594         size_t packet_size_len;
 595         size_t block_aligned_filename_size;
 596         size_t block_size;
 597         size_t i;
 598         size_t j;
 599         size_t num_rand_bytes;
 600         struct mutex *tfm_mutex;
 601         char *block_aligned_filename;
 602         struct ecryptfs_auth_tok *auth_tok;
 603         struct scatterlist src_sg[2];
 604         struct scatterlist dst_sg[2];
 605         struct crypto_skcipher *skcipher_tfm;
 606         struct skcipher_request *skcipher_req;
 607         char iv[ECRYPTFS_MAX_IV_BYTES];
 608         char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 609         char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 610         struct crypto_shash *hash_tfm;
 611         struct shash_desc *hash_desc;
 612 };
 613
 614 /**
 615  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
 616  * @filename: NULL-terminated filename string
 617  *
 618  * This is the simplest mechanism for achieving filename encryption in
 619  * eCryptfs. It encrypts the given filename with the mount-wide
 620  * filename encryption key (FNEK) and stores it in a packet to @dest,
 621  * which the callee will encode and write directly into the dentry
 622  * name.
 623  */
 624 int
 625 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
 626                              size_t *packet_size,
 627                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 628                              char *filename, size_t filename_size)
 629 {
 630         struct ecryptfs_write_tag_70_packet_silly_stack *s;
 631         struct key *auth_tok_key = NULL;
 632         int rc = 0;
 633
 634         s = kzalloc(sizeof(*s), GFP_KERNEL);
 635         if (!s) {
 636                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 637                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 638                 return -ENOMEM;
 639         }
 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->skcipher_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_skcipher_blocksize(s->skcipher_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 = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
 682                               + s->block_aligned_filename_size);
 683         if (dest == NULL) {
 684                 (*packet_size) = s->max_packet_size;
 685                 goto out_unlock;
 686         }
 687         if (s->max_packet_size > (*remaining_bytes)) {
 688                 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
 689                        "[%zd] available\n", __func__, s->max_packet_size,
 690                        (*remaining_bytes));
 691                 rc = -EINVAL;
 692                 goto out_unlock;
 693         }
 694
 695         s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
 696         if (!s->skcipher_req) {
 697                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 698                        "skcipher_request_alloc for %s\n", __func__,
 699                        crypto_skcipher_driver_name(s->skcipher_tfm));
 700                 rc = -ENOMEM;
 701                 goto out_unlock;
 702         }
 703
 704         skcipher_request_set_callback(s->skcipher_req,
 705                                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
 706
 707         s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
 708                                             GFP_KERNEL);
 709         if (!s->block_aligned_filename) {
 710                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 711                        "kzalloc [%zd] bytes\n", __func__,
 712                        s->block_aligned_filename_size);
 713                 rc = -ENOMEM;
 714                 goto out_unlock;
 715         }
 716         dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
 717         rc = ecryptfs_write_packet_length(&dest[s->i],
 718                                           (ECRYPTFS_SIG_SIZE
 719                                            + 1 /* Cipher code */
 720                                            + s->block_aligned_filename_size),
 721                                           &s->packet_size_len);
 722         if (rc) {
 723                 printk(KERN_ERR "%s: Error generating tag 70 packet "
 724                        "header; cannot generate packet length; rc = [%d]\n",
 725                        __func__, rc);
 726                 goto out_free_unlock;
 727         }
 728         s->i += s->packet_size_len;
 729         ecryptfs_from_hex(&dest[s->i],
 730                           mount_crypt_stat->global_default_fnek_sig,
 731                           ECRYPTFS_SIG_SIZE);
 732         s->i += ECRYPTFS_SIG_SIZE;
 733         s->cipher_code = ecryptfs_code_for_cipher_string(
 734                 mount_crypt_stat->global_default_fn_cipher_name,
 735                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 736         if (s->cipher_code == 0) {
 737                 printk(KERN_WARNING "%s: Unable to generate code for "
 738                        "cipher [%s] with key bytes [%zd]\n", __func__,
 739                        mount_crypt_stat->global_default_fn_cipher_name,
 740                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 741                 rc = -EINVAL;
 742                 goto out_free_unlock;
 743         }
 744         dest[s->i++] = s->cipher_code;
 745         /* TODO: Support other key modules than passphrase for
 746          * filename encryption */
 747         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
 748                 rc = -EOPNOTSUPP;
 749                 printk(KERN_INFO "%s: Filename encryption only supports "
 750                        "password tokens\n", __func__);
 751                 goto out_free_unlock;
 752         }
 753         s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
 754         if (IS_ERR(s->hash_tfm)) {
 755                         rc = PTR_ERR(s->hash_tfm);
 756                         printk(KERN_ERR "%s: Error attempting to "
 757                                "allocate hash crypto context; rc = [%d]\n",
 758                                __func__, rc);
 759                         goto out_free_unlock;
 760         }
 761
 762         s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
 763                                crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
 764         if (!s->hash_desc) {
 765                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 766                        "kmalloc [%zd] bytes\n", __func__,
 767                        sizeof(*s->hash_desc) +
 768                        crypto_shash_descsize(s->hash_tfm));
 769                 rc = -ENOMEM;
 770                 goto out_release_free_unlock;
 771         }
 772
 773         s->hash_desc->tfm = s->hash_tfm;
 774         s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 775
 776         rc = crypto_shash_digest(s->hash_desc,
 777                                  (u8 *)s->auth_tok->token.password.session_key_encryption_key,
 778                                  s->auth_tok->token.password.session_key_encryption_key_bytes,
 779                                  s->hash);
 780         if (rc) {
 781                 printk(KERN_ERR
 782                        "%s: Error computing crypto hash; rc = [%d]\n",
 783                        __func__, rc);
 784                 goto out_release_free_unlock;
 785         }
 786         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
 787                 s->block_aligned_filename[s->j] =
 788                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
 789                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
 790                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
 791                         rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
 792                                                 ECRYPTFS_TAG_70_DIGEST_SIZE,
 793                                                 s->tmp_hash);
 794                         if (rc) {
 795                                 printk(KERN_ERR
 796                                        "%s: Error computing crypto hash; "
 797                                        "rc = [%d]\n", __func__, rc);
 798                                 goto out_release_free_unlock;
 799                         }
 800                         memcpy(s->hash, s->tmp_hash,
 801                                ECRYPTFS_TAG_70_DIGEST_SIZE);
 802                 }
 803                 if (s->block_aligned_filename[s->j] == '\0')
 804                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
 805         }
 806         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
 807                filename_size);
 808         rc = virt_to_scatterlist(s->block_aligned_filename,
 809                                  s->block_aligned_filename_size, s->src_sg, 2);
 810         if (rc < 1) {
 811                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 812                        "convert filename memory to scatterlist; rc = [%d]. "
 813                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 814                        s->block_aligned_filename_size);
 815                 goto out_release_free_unlock;
 816         }
 817         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
 818                                  s->dst_sg, 2);
 819         if (rc < 1) {
 820                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 821                        "convert encrypted filename memory to scatterlist; "
 822                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
 823                        __func__, rc, s->block_aligned_filename_size);
 824                 goto out_release_free_unlock;
 825         }
 826         /* The characters in the first block effectively do the job
 827          * of the IV here, so we just use 0's for the IV. Note the
 828          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 829          * >= ECRYPTFS_MAX_IV_BYTES. */
 830         rc = crypto_skcipher_setkey(
 831                 s->skcipher_tfm,
 832                 s->auth_tok->token.password.session_key_encryption_key,
 833                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 834         if (rc < 0) {
 835                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 836                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 837                        "encryption_key = [0x%p]; mount_crypt_stat->"
 838                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 839                        rc,
 840                        s->auth_tok->token.password.session_key_encryption_key,
 841                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 842                 goto out_release_free_unlock;
 843         }
 844         skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
 845                                    s->block_aligned_filename_size, s->iv);
 846         rc = crypto_skcipher_encrypt(s->skcipher_req);
 847         if (rc) {
 848                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
 849                        "rc = [%d]\n", __func__, rc);
 850                 goto out_release_free_unlock;
 851         }
 852         s->i += s->block_aligned_filename_size;
 853         (*packet_size) = s->i;
 854         (*remaining_bytes) -= (*packet_size);
 855 out_release_free_unlock:
 856         crypto_free_shash(s->hash_tfm);
 857 out_free_unlock:
 858         kzfree(s->block_aligned_filename);
 859 out_unlock:
 860         mutex_unlock(s->tfm_mutex);
 861 out:
 862         if (auth_tok_key) {
 863                 up_write(&(auth_tok_key->sem));
 864                 key_put(auth_tok_key);
 865         }
 866         skcipher_request_free(s->skcipher_req);
 867         kzfree(s->hash_desc);
 868         kfree(s);
 869         return rc;
 870 }
 871
 872 struct ecryptfs_parse_tag_70_packet_silly_stack {
 873         u8 cipher_code;
 874         size_t max_packet_size;
 875         size_t packet_size_len;
 876         size_t parsed_tag_70_packet_size;
 877         size_t block_aligned_filename_size;
 878         size_t block_size;
 879         size_t i;
 880         struct mutex *tfm_mutex;
 881         char *decrypted_filename;
 882         struct ecryptfs_auth_tok *auth_tok;
 883         struct scatterlist src_sg[2];
 884         struct scatterlist dst_sg[2];
 885         struct crypto_skcipher *skcipher_tfm;
 886         struct skcipher_request *skcipher_req;
 887         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
 888         char iv[ECRYPTFS_MAX_IV_BYTES];
 889         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
 890 };
 891
 892 /**
 893  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
 894  * @filename: This function kmalloc's the memory for the filename
 895  * @filename_size: This function sets this to the amount of memory
 896  *                 kmalloc'd for the filename
 897  * @packet_size: This function sets this to the the number of octets
 898  *               in the packet parsed
 899  * @mount_crypt_stat: The mount-wide cryptographic context
 900  * @data: The memory location containing the start of the tag 70
 901  *        packet
 902  * @max_packet_size: The maximum legal size of the packet to be parsed
 903  *                   from @data
 904  *
 905  * Returns zero on success; non-zero otherwise
 906  */
 907 int
 908 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 909                              size_t *packet_size,
 910                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 911                              char *data, size_t max_packet_size)
 912 {
 913         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
 914         struct key *auth_tok_key = NULL;
 915         int rc = 0;
 916
 917         (*packet_size) = 0;
 918         (*filename_size) = 0;
 919         (*filename) = NULL;
 920         s = kzalloc(sizeof(*s), GFP_KERNEL);
 921         if (!s) {
 922                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 923                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 924                 return -ENOMEM;
 925         }
 926         if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
 927                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
 928                        "at least [%d]\n", __func__, max_packet_size,
 929                        ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
 930                 rc = -EINVAL;
 931                 goto out;
 932         }
 933         /* Octet 0: Tag 70 identifier
 934          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 935          *              and block-aligned encrypted filename size)
 936          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 937          * Octet N2-N3: Cipher identifier (1 octet)
 938          * Octets N3-N4: Block-aligned encrypted filename
 939          *  - Consists of a minimum number of random numbers, a \0
 940          *    separator, and then the filename */
 941         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
 942                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
 943                        "tag [0x%.2x]\n", __func__,
 944                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
 945                 rc = -EINVAL;
 946                 goto out;
 947         }
 948         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
 949                                           &s->parsed_tag_70_packet_size,
 950                                           &s->packet_size_len);
 951         if (rc) {
 952                 printk(KERN_WARNING "%s: Error parsing packet length; "
 953                        "rc = [%d]\n", __func__, rc);
 954                 goto out;
 955         }
 956         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
 957                                           - ECRYPTFS_SIG_SIZE - 1);
 958         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
 959             > max_packet_size) {
 960                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
 961                        "size is [%zd]\n", __func__, max_packet_size,
 962                        (1 + s->packet_size_len + 1
 963                         + s->block_aligned_filename_size));
 964                 rc = -EINVAL;
 965                 goto out;
 966         }
 967         (*packet_size) += s->packet_size_len;
 968         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
 969                         ECRYPTFS_SIG_SIZE);
 970         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 971         (*packet_size) += ECRYPTFS_SIG_SIZE;
 972         s->cipher_code = data[(*packet_size)++];
 973         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
 974         if (rc) {
 975                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
 976                        __func__, s->cipher_code);
 977                 goto out;
 978         }
 979         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
 980                                             &s->auth_tok, mount_crypt_stat,
 981                                             s->fnek_sig_hex);
 982         if (rc) {
 983                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 984                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
 985                        rc);
 986                 goto out;
 987         }
 988         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
 989                                                         &s->tfm_mutex,
 990                                                         s->cipher_string);
 991         if (unlikely(rc)) {
 992                 printk(KERN_ERR "Internal error whilst attempting to get "
 993                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
 994                        s->cipher_string, rc);
 995                 goto out;
 996         }
 997         mutex_lock(s->tfm_mutex);
 998         rc = virt_to_scatterlist(&data[(*packet_size)],
 999                                  s->block_aligned_filename_size, s->src_sg, 2);
1000         if (rc < 1) {
1001                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1002                        "convert encrypted filename memory to scatterlist; "
1003                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1004                        __func__, rc, s->block_aligned_filename_size);
1005                 goto out_unlock;
1006         }
1007         (*packet_size) += s->block_aligned_filename_size;
1008         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1009                                         GFP_KERNEL);
1010         if (!s->decrypted_filename) {
1011                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1012                        "kmalloc [%zd] bytes\n", __func__,
1013                        s->block_aligned_filename_size);
1014                 rc = -ENOMEM;
1015                 goto out_unlock;
1016         }
1017         rc = virt_to_scatterlist(s->decrypted_filename,
1018                                  s->block_aligned_filename_size, s->dst_sg, 2);
1019         if (rc < 1) {
1020                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1021                        "convert decrypted filename memory to scatterlist; "
1022                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1023                        __func__, rc, s->block_aligned_filename_size);
1024                 goto out_free_unlock;
1025         }
1026
1027         s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1028         if (!s->skcipher_req) {
1029                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1030                        "skcipher_request_alloc for %s\n", __func__,
1031                        crypto_skcipher_driver_name(s->skcipher_tfm));
1032                 rc = -ENOMEM;
1033                 goto out_free_unlock;
1034         }
1035
1036         skcipher_request_set_callback(s->skcipher_req,
1037                                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1038
1039         /* The characters in the first block effectively do the job of
1040          * the IV here, so we just use 0's for the IV. Note the
1041          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1042          * >= ECRYPTFS_MAX_IV_BYTES. */
1043         /* TODO: Support other key modules than passphrase for
1044          * filename encryption */
1045         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1046                 rc = -EOPNOTSUPP;
1047                 printk(KERN_INFO "%s: Filename encryption only supports "
1048                        "password tokens\n", __func__);
1049                 goto out_free_unlock;
1050         }
1051         rc = crypto_skcipher_setkey(
1052                 s->skcipher_tfm,
1053                 s->auth_tok->token.password.session_key_encryption_key,
1054                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1055         if (rc < 0) {
1056                 printk(KERN_ERR "%s: Error setting key for crypto context; "
1057                        "rc = [%d]. s->auth_tok->token.password.session_key_"
1058                        "encryption_key = [0x%p]; mount_crypt_stat->"
1059                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1060                        rc,
1061                        s->auth_tok->token.password.session_key_encryption_key,
1062                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
1063                 goto out_free_unlock;
1064         }
1065         skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1066                                    s->block_aligned_filename_size, s->iv);
1067         rc = crypto_skcipher_decrypt(s->skcipher_req);
1068         if (rc) {
1069                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1070                        "rc = [%d]\n", __func__, rc);
1071                 goto out_free_unlock;
1072         }
1073         while (s->decrypted_filename[s->i] != '\0'
1074                && s->i < s->block_aligned_filename_size)
1075                 s->i++;
1076         if (s->i == s->block_aligned_filename_size) {
1077                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1078                        "find valid separator between random characters and "
1079                        "the filename\n", __func__);
1080                 rc = -EINVAL;
1081                 goto out_free_unlock;
1082         }
1083         s->i++;
1084         (*filename_size) = (s->block_aligned_filename_size - s->i);
1085         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1086                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1087                        "invalid\n", __func__, (*filename_size));
1088                 rc = -EINVAL;
1089                 goto out_free_unlock;
1090         }
1091         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1092         if (!(*filename)) {
1093                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1094                        "kmalloc [%zd] bytes\n", __func__,
1095                        ((*filename_size) + 1));
1096                 rc = -ENOMEM;
1097                 goto out_free_unlock;
1098         }
1099         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1100         (*filename)[(*filename_size)] = '\0';
1101 out_free_unlock:
1102         kfree(s->decrypted_filename);
1103 out_unlock:
1104         mutex_unlock(s->tfm_mutex);
1105 out:
1106         if (rc) {
1107                 (*packet_size) = 0;
1108                 (*filename_size) = 0;
1109                 (*filename) = NULL;
1110         }
1111         if (auth_tok_key) {
1112                 up_write(&(auth_tok_key->sem));
1113                 key_put(auth_tok_key);
1114         }
1115         skcipher_request_free(s->skcipher_req);
1116         kfree(s);
1117         return rc;
1118 }
1119
1120 static int
1121 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1122 {
1123         int rc = 0;
1124
1125         (*sig) = NULL;
1126         switch (auth_tok->token_type) {
1127         case ECRYPTFS_PASSWORD:
1128                 (*sig) = auth_tok->token.password.signature;
1129                 break;
1130         case ECRYPTFS_PRIVATE_KEY:
1131                 (*sig) = auth_tok->token.private_key.signature;
1132                 break;
1133         default:
1134                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1135                        auth_tok->token_type);
1136                 rc = -EINVAL;
1137         }
1138         return rc;
1139 }
1140
1141 /**
1142  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1143  * @auth_tok: The key authentication token used to decrypt the session key
1144  * @crypt_stat: The cryptographic context
1145  *
1146  * Returns zero on success; non-zero error otherwise.
1147  */
1148 static int
1149 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1150                                   struct ecryptfs_crypt_stat *crypt_stat)
1151 {
1152         u8 cipher_code = 0;
1153         struct ecryptfs_msg_ctx *msg_ctx;
1154         struct ecryptfs_message *msg = NULL;
1155         char *auth_tok_sig;
1156         char *payload = NULL;
1157         size_t payload_len = 0;
1158         int rc;
1159
1160         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1161         if (rc) {
1162                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1163                        auth_tok->token_type);
1164                 goto out;
1165         }
1166         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1167                                  &payload, &payload_len);
1168         if (rc) {
1169                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1170                 goto out;
1171         }
1172         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1173         if (rc) {
1174                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1175                                 "ecryptfsd: %d\n", rc);
1176                 goto out;
1177         }
1178         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1179         if (rc) {
1180                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1181                                 "from the user space daemon\n");
1182                 rc = -EIO;
1183                 goto out;
1184         }
1185         rc = parse_tag_65_packet(&(auth_tok->session_key),
1186                                  &cipher_code, msg);
1187         if (rc) {
1188                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1189                        rc);
1190                 goto out;
1191         }
1192         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1193         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1194                auth_tok->session_key.decrypted_key_size);
1195         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1196         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1197         if (rc) {
1198                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1199                                 cipher_code)
1200                 goto out;
1201         }
1202         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1203         if (ecryptfs_verbosity > 0) {
1204                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1205                 ecryptfs_dump_hex(crypt_stat->key,
1206                                   crypt_stat->key_size);
1207         }
1208 out:
1209         kfree(msg);
1210         kfree(payload);
1211         return rc;
1212 }
1213
1214 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1215 {
1216         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1217         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1218
1219         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1220                                  auth_tok_list_head, list) {
1221                 list_del(&auth_tok_list_item->list);
1222                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1223                                 auth_tok_list_item);
1224         }
1225 }
1226
1227 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1228
1229 /**
1230  * parse_tag_1_packet
1231  * @crypt_stat: The cryptographic context to modify based on packet contents
1232  * @data: The raw bytes of the packet.
1233  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1234  *                 a new authentication token will be placed at the
1235  *                 end of this list for this packet.
1236  * @new_auth_tok: Pointer to a pointer to memory that this function
1237  *                allocates; sets the memory address of the pointer to
1238  *                NULL on error. This object is added to the
1239  *                auth_tok_list.
1240  * @packet_size: This function writes the size of the parsed packet
1241  *               into this memory location; zero on error.
1242  * @max_packet_size: The maximum allowable packet size
1243  *
1244  * Returns zero on success; non-zero on error.
1245  */
1246 static int
1247 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1248                    unsigned char *data, struct list_head *auth_tok_list,
1249                    struct ecryptfs_auth_tok **new_auth_tok,
1250                    size_t *packet_size, size_t max_packet_size)
1251 {
1252         size_t body_size;
1253         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1254         size_t length_size;
1255         int rc = 0;
1256
1257         (*packet_size) = 0;
1258         (*new_auth_tok) = NULL;
1259         /**
1260          * This format is inspired by OpenPGP; see RFC 2440
1261          * packet tag 1
1262          *
1263          * Tag 1 identifier (1 byte)
1264          * Max Tag 1 packet size (max 3 bytes)
1265          * Version (1 byte)
1266          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1267          * Cipher identifier (1 byte)
1268          * Encrypted key size (arbitrary)
1269          *
1270          * 12 bytes minimum packet size
1271          */
1272         if (unlikely(max_packet_size < 12)) {
1273                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1274                 rc = -EINVAL;
1275                 goto out;
1276         }
1277         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1278                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1279                        ECRYPTFS_TAG_1_PACKET_TYPE);
1280                 rc = -EINVAL;
1281                 goto out;
1282         }
1283         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1284          * at end of function upon failure */
1285         auth_tok_list_item =
1286                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1287                                   GFP_KERNEL);
1288         if (!auth_tok_list_item) {
1289                 printk(KERN_ERR "Unable to allocate memory\n");
1290                 rc = -ENOMEM;
1291                 goto out;
1292         }
1293         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1294         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1295                                           &length_size);
1296         if (rc) {
1297                 printk(KERN_WARNING "Error parsing packet length; "
1298                        "rc = [%d]\n", rc);
1299                 goto out_free;
1300         }
1301         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1302                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1303                 rc = -EINVAL;
1304                 goto out_free;
1305         }
1306         (*packet_size) += length_size;
1307         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1308                 printk(KERN_WARNING "Packet size exceeds max\n");
1309                 rc = -EINVAL;
1310                 goto out_free;
1311         }
1312         if (unlikely(data[(*packet_size)++] != 0x03)) {
1313                 printk(KERN_WARNING "Unknown version number [%d]\n",
1314                        data[(*packet_size) - 1]);
1315                 rc = -EINVAL;
1316                 goto out_free;
1317         }
1318         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1319                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1320         *packet_size += ECRYPTFS_SIG_SIZE;
1321         /* This byte is skipped because the kernel does not need to
1322          * know which public key encryption algorithm was used */
1323         (*packet_size)++;
1324         (*new_auth_tok)->session_key.encrypted_key_size =
1325                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1326         if ((*new_auth_tok)->session_key.encrypted_key_size
1327             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1328                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1329                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1330                 rc = -EINVAL;
1331                 goto out;
1332         }
1333         memcpy((*new_auth_tok)->session_key.encrypted_key,
1334                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1335         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1336         (*new_auth_tok)->session_key.flags &=
1337                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1338         (*new_auth_tok)->session_key.flags |=
1339                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1340         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1341         (*new_auth_tok)->flags = 0;
1342         (*new_auth_tok)->session_key.flags &=
1343                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1344         (*new_auth_tok)->session_key.flags &=
1345                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1346         list_add(&auth_tok_list_item->list, auth_tok_list);
1347         goto out;
1348 out_free:
1349         (*new_auth_tok) = NULL;
1350         memset(auth_tok_list_item, 0,
1351                sizeof(struct ecryptfs_auth_tok_list_item));
1352         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1353                         auth_tok_list_item);
1354 out:
1355         if (rc)
1356                 (*packet_size) = 0;
1357         return rc;
1358 }
1359
1360 /**
1361  * parse_tag_3_packet
1362  * @crypt_stat: The cryptographic context to modify based on packet
1363  *              contents.
1364  * @data: The raw bytes of the packet.
1365  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1366  *                 a new authentication token will be placed at the end
1367  *                 of this list for this packet.
1368  * @new_auth_tok: Pointer to a pointer to memory that this function
1369  *                allocates; sets the memory address of the pointer to
1370  *                NULL on error. This object is added to the
1371  *                auth_tok_list.
1372  * @packet_size: This function writes the size of the parsed packet
1373  *               into this memory location; zero on error.
1374  * @max_packet_size: maximum number of bytes to parse
1375  *
1376  * Returns zero on success; non-zero on error.
1377  */
1378 static int
1379 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1380                    unsigned char *data, struct list_head *auth_tok_list,
1381                    struct ecryptfs_auth_tok **new_auth_tok,
1382                    size_t *packet_size, size_t max_packet_size)
1383 {
1384         size_t body_size;
1385         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1386         size_t length_size;
1387         int rc = 0;
1388
1389         (*packet_size) = 0;
1390         (*new_auth_tok) = NULL;
1391         /**
1392          *This format is inspired by OpenPGP; see RFC 2440
1393          * packet tag 3
1394          *
1395          * Tag 3 identifier (1 byte)
1396          * Max Tag 3 packet size (max 3 bytes)
1397          * Version (1 byte)
1398          * Cipher code (1 byte)
1399          * S2K specifier (1 byte)
1400          * Hash identifier (1 byte)
1401          * Salt (ECRYPTFS_SALT_SIZE)
1402          * Hash iterations (1 byte)
1403          * Encrypted key (arbitrary)
1404          *
1405          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1406          */
1407         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1408                 printk(KERN_ERR "Max packet size too large\n");
1409                 rc = -EINVAL;
1410                 goto out;
1411         }
1412         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1413                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1414                        ECRYPTFS_TAG_3_PACKET_TYPE);
1415                 rc = -EINVAL;
1416                 goto out;
1417         }
1418         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1419          * at end of function upon failure */
1420         auth_tok_list_item =
1421             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1422         if (!auth_tok_list_item) {
1423                 printk(KERN_ERR "Unable to allocate memory\n");
1424                 rc = -ENOMEM;
1425                 goto out;
1426         }
1427         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1428         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1429                                           &length_size);
1430         if (rc) {
1431                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1432                        rc);
1433                 goto out_free;
1434         }
1435         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1436                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1437                 rc = -EINVAL;
1438                 goto out_free;
1439         }
1440         (*packet_size) += length_size;
1441         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1442                 printk(KERN_ERR "Packet size exceeds max\n");
1443                 rc = -EINVAL;
1444                 goto out_free;
1445         }
1446         (*new_auth_tok)->session_key.encrypted_key_size =
1447                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1448         if ((*new_auth_tok)->session_key.encrypted_key_size
1449             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1450                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1451                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1452                 rc = -EINVAL;
1453                 goto out_free;
1454         }
1455         if (unlikely(data[(*packet_size)++] != 0x04)) {
1456                 printk(KERN_WARNING "Unknown version number [%d]\n",
1457                        data[(*packet_size) - 1]);
1458                 rc = -EINVAL;
1459                 goto out_free;
1460         }
1461         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1462                                             (u16)data[(*packet_size)]);
1463         if (rc)
1464                 goto out_free;
1465         /* A little extra work to differentiate among the AES key
1466          * sizes; see RFC2440 */
1467         switch(data[(*packet_size)++]) {
1468         case RFC2440_CIPHER_AES_192:
1469                 crypt_stat->key_size = 24;
1470                 break;
1471         default:
1472                 crypt_stat->key_size =
1473                         (*new_auth_tok)->session_key.encrypted_key_size;
1474         }
1475         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1476         if (rc)
1477                 goto out_free;
1478         if (unlikely(data[(*packet_size)++] != 0x03)) {
1479                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1480                 rc = -ENOSYS;
1481                 goto out_free;
1482         }
1483         /* TODO: finish the hash mapping */
1484         switch (data[(*packet_size)++]) {
1485         case 0x01: /* See RFC2440 for these numbers and their mappings */
1486                 /* Choose MD5 */
1487                 memcpy((*new_auth_tok)->token.password.salt,
1488                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1489                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1490                 /* This conversion was taken straight from RFC2440 */
1491                 (*new_auth_tok)->token.password.hash_iterations =
1492                         ((u32) 16 + (data[(*packet_size)] & 15))
1493                                 << ((data[(*packet_size)] >> 4) + 6);
1494                 (*packet_size)++;
1495                 /* Friendly reminder:
1496                  * (*new_auth_tok)->session_key.encrypted_key_size =
1497                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1498                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1499                        &data[(*packet_size)],
1500                        (*new_auth_tok)->session_key.encrypted_key_size);
1501                 (*packet_size) +=
1502                         (*new_auth_tok)->session_key.encrypted_key_size;
1503                 (*new_auth_tok)->session_key.flags &=
1504                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1505                 (*new_auth_tok)->session_key.flags |=
1506                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1507                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1508                 break;
1509         default:
1510                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1511                                 "[%d]\n", data[(*packet_size) - 1]);
1512                 rc = -ENOSYS;
1513                 goto out_free;
1514         }
1515         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1516         /* TODO: Parametarize; we might actually want userspace to
1517          * decrypt the session key. */
1518         (*new_auth_tok)->session_key.flags &=
1519                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1520         (*new_auth_tok)->session_key.flags &=
1521                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1522         list_add(&auth_tok_list_item->list, auth_tok_list);
1523         goto out;
1524 out_free:
1525         (*new_auth_tok) = NULL;
1526         memset(auth_tok_list_item, 0,
1527                sizeof(struct ecryptfs_auth_tok_list_item));
1528         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1529                         auth_tok_list_item);
1530 out:
1531         if (rc)
1532                 (*packet_size) = 0;
1533         return rc;
1534 }
1535
1536 /**
1537  * parse_tag_11_packet
1538  * @data: The raw bytes of the packet
1539  * @contents: This function writes the data contents of the literal
1540  *            packet into this memory location
1541  * @max_contents_bytes: The maximum number of bytes that this function
1542  *                      is allowed to write into contents
1543  * @tag_11_contents_size: This function writes the size of the parsed
1544  *                        contents into this memory location; zero on
1545  *                        error
1546  * @packet_size: This function writes the size of the parsed packet
1547  *               into this memory location; zero on error
1548  * @max_packet_size: maximum number of bytes to parse
1549  *
1550  * Returns zero on success; non-zero on error.
1551  */
1552 static int
1553 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1554                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1555                     size_t *packet_size, size_t max_packet_size)
1556 {
1557         size_t body_size;
1558         size_t length_size;
1559         int rc = 0;
1560
1561         (*packet_size) = 0;
1562         (*tag_11_contents_size) = 0;
1563         /* This format is inspired by OpenPGP; see RFC 2440
1564          * packet tag 11
1565          *
1566          * Tag 11 identifier (1 byte)
1567          * Max Tag 11 packet size (max 3 bytes)
1568          * Binary format specifier (1 byte)
1569          * Filename length (1 byte)
1570          * Filename ("_CONSOLE") (8 bytes)
1571          * Modification date (4 bytes)
1572          * Literal data (arbitrary)
1573          *
1574          * We need at least 16 bytes of data for the packet to even be
1575          * valid.
1576          */
1577         if (max_packet_size < 16) {
1578                 printk(KERN_ERR "Maximum packet size too small\n");
1579                 rc = -EINVAL;
1580                 goto out;
1581         }
1582         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1583                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1584                 rc = -EINVAL;
1585                 goto out;
1586         }
1587         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1588                                           &length_size);
1589         if (rc) {
1590                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1591                 goto out;
1592         }
1593         if (body_size < 14) {
1594                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1595                 rc = -EINVAL;
1596                 goto out;
1597         }
1598         (*packet_size) += length_size;
1599         (*tag_11_contents_size) = (body_size - 14);
1600         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1601                 printk(KERN_ERR "Packet size exceeds max\n");
1602                 rc = -EINVAL;
1603                 goto out;
1604         }
1605         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1606                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1607                        "expected size\n");
1608                 rc = -EINVAL;
1609                 goto out;
1610         }
1611         if (data[(*packet_size)++] != 0x62) {
1612                 printk(KERN_WARNING "Unrecognizable packet\n");
1613                 rc = -EINVAL;
1614                 goto out;
1615         }
1616         if (data[(*packet_size)++] != 0x08) {
1617                 printk(KERN_WARNING "Unrecognizable packet\n");
1618                 rc = -EINVAL;
1619                 goto out;
1620         }
1621         (*packet_size) += 12; /* Ignore filename and modification date */
1622         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1623         (*packet_size) += (*tag_11_contents_size);
1624 out:
1625         if (rc) {
1626                 (*packet_size) = 0;
1627                 (*tag_11_contents_size) = 0;
1628         }
1629         return rc;
1630 }
1631
1632 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1633                                       struct ecryptfs_auth_tok **auth_tok,
1634                                       char *sig)
1635 {
1636         int rc = 0;
1637
1638         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1639         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1640                 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1641                 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1642                         printk(KERN_ERR "Could not find key with description: [%s]\n",
1643                               sig);
1644                         rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1645                         (*auth_tok_key) = NULL;
1646                         goto out;
1647                 }
1648         }
1649         down_write(&(*auth_tok_key)->sem);
1650         rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1651         if (rc) {
1652                 up_write(&(*auth_tok_key)->sem);
1653                 key_put(*auth_tok_key);
1654                 (*auth_tok_key) = NULL;
1655                 goto out;
1656         }
1657 out:
1658         return rc;
1659 }
1660
1661 /**
1662  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1663  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1664  * @crypt_stat: The cryptographic context
1665  *
1666  * Returns zero on success; non-zero error otherwise
1667  */
1668 static int
1669 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1670                                          struct ecryptfs_crypt_stat *crypt_stat)
1671 {
1672         struct scatterlist dst_sg[2];
1673         struct scatterlist src_sg[2];
1674         struct mutex *tfm_mutex;
1675         struct crypto_skcipher *tfm;
1676         struct skcipher_request *req = NULL;
1677         int rc = 0;
1678
1679         if (unlikely(ecryptfs_verbosity > 0)) {
1680                 ecryptfs_printk(
1681                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1682                         auth_tok->token.password.session_key_encryption_key_bytes);
1683                 ecryptfs_dump_hex(
1684                         auth_tok->token.password.session_key_encryption_key,
1685                         auth_tok->token.password.session_key_encryption_key_bytes);
1686         }
1687         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1688                                                         crypt_stat->cipher);
1689         if (unlikely(rc)) {
1690                 printk(KERN_ERR "Internal error whilst attempting to get "
1691                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1692                        crypt_stat->cipher, rc);
1693                 goto out;
1694         }
1695         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1696                                  auth_tok->session_key.encrypted_key_size,
1697                                  src_sg, 2);
1698         if (rc < 1 || rc > 2) {
1699                 printk(KERN_ERR "Internal error whilst attempting to convert "
1700                         "auth_tok->session_key.encrypted_key to scatterlist; "
1701                         "expected rc = 1; got rc = [%d]. "
1702                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1703                         auth_tok->session_key.encrypted_key_size);
1704                 goto out;
1705         }
1706         auth_tok->session_key.decrypted_key_size =
1707                 auth_tok->session_key.encrypted_key_size;
1708         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1709                                  auth_tok->session_key.decrypted_key_size,
1710                                  dst_sg, 2);
1711         if (rc < 1 || rc > 2) {
1712                 printk(KERN_ERR "Internal error whilst attempting to convert "
1713                         "auth_tok->session_key.decrypted_key to scatterlist; "
1714                         "expected rc = 1; got rc = [%d]\n", rc);
1715                 goto out;
1716         }
1717         mutex_lock(tfm_mutex);
1718         req = skcipher_request_alloc(tfm, GFP_KERNEL);
1719         if (!req) {
1720                 mutex_unlock(tfm_mutex);
1721                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1722                        "skcipher_request_alloc for %s\n", __func__,
1723                        crypto_skcipher_driver_name(tfm));
1724                 rc = -ENOMEM;
1725                 goto out;
1726         }
1727
1728         skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1729                                       NULL, NULL);
1730         rc = crypto_skcipher_setkey(
1731                 tfm, auth_tok->token.password.session_key_encryption_key,
1732                 crypt_stat->key_size);
1733         if (unlikely(rc < 0)) {
1734                 mutex_unlock(tfm_mutex);
1735                 printk(KERN_ERR "Error setting key for crypto context\n");
1736                 rc = -EINVAL;
1737                 goto out;
1738         }
1739         skcipher_request_set_crypt(req, src_sg, dst_sg,
1740                                    auth_tok->session_key.encrypted_key_size,
1741                                    NULL);
1742         rc = crypto_skcipher_decrypt(req);
1743         mutex_unlock(tfm_mutex);
1744         if (unlikely(rc)) {
1745                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1746                 goto out;
1747         }
1748         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1749         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1750                auth_tok->session_key.decrypted_key_size);
1751         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1752         if (unlikely(ecryptfs_verbosity > 0)) {
1753                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1754                                 crypt_stat->key_size);
1755                 ecryptfs_dump_hex(crypt_stat->key,
1756                                   crypt_stat->key_size);
1757         }
1758 out:
1759         skcipher_request_free(req);
1760         return rc;
1761 }
1762
1763 /**
1764  * ecryptfs_parse_packet_set
1765  * @crypt_stat: The cryptographic context
1766  * @src: Virtual address of region of memory containing the packets
1767  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1768  *
1769  * Get crypt_stat to have the file's session key if the requisite key
1770  * is available to decrypt the session key.
1771  *
1772  * Returns Zero if a valid authentication token was retrieved and
1773  * processed; negative value for file not encrypted or for error
1774  * conditions.
1775  */
1776 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1777                               unsigned char *src,
1778                               struct dentry *ecryptfs_dentry)
1779 {
1780         size_t i = 0;
1781         size_t found_auth_tok;
1782         size_t next_packet_is_auth_tok_packet;
1783         struct list_head auth_tok_list;
1784         struct ecryptfs_auth_tok *matching_auth_tok;
1785         struct ecryptfs_auth_tok *candidate_auth_tok;
1786         char *candidate_auth_tok_sig;
1787         size_t packet_size;
1788         struct ecryptfs_auth_tok *new_auth_tok;
1789         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1790         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1791         size_t tag_11_contents_size;
1792         size_t tag_11_packet_size;
1793         struct key *auth_tok_key = NULL;
1794         int rc = 0;
1795
1796         INIT_LIST_HEAD(&auth_tok_list);
1797         /* Parse the header to find as many packets as we can; these will be
1798          * added the our &auth_tok_list */
1799         next_packet_is_auth_tok_packet = 1;
1800         while (next_packet_is_auth_tok_packet) {
1801                 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1802
1803                 switch (src[i]) {
1804                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1805                         rc = parse_tag_3_packet(crypt_stat,
1806                                                 (unsigned char *)&src[i],
1807                                                 &auth_tok_list, &new_auth_tok,
1808                                                 &packet_size, max_packet_size);
1809                         if (rc) {
1810                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1811                                                 "tag 3 packet\n");
1812                                 rc = -EIO;
1813                                 goto out_wipe_list;
1814                         }
1815                         i += packet_size;
1816                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1817                                                  sig_tmp_space,
1818                                                  ECRYPTFS_SIG_SIZE,
1819                                                  &tag_11_contents_size,
1820                                                  &tag_11_packet_size,
1821                                                  max_packet_size);
1822                         if (rc) {
1823                                 ecryptfs_printk(KERN_ERR, "No valid "
1824                                                 "(ecryptfs-specific) literal "
1825                                                 "packet containing "
1826                                                 "authentication token "
1827                                                 "signature found after "
1828                                                 "tag 3 packet\n");
1829                                 rc = -EIO;
1830                                 goto out_wipe_list;
1831                         }
1832                         i += tag_11_packet_size;
1833                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1834                                 ecryptfs_printk(KERN_ERR, "Expected "
1835                                                 "signature of size [%d]; "
1836                                                 "read size [%zd]\n",
1837                                                 ECRYPTFS_SIG_SIZE,
1838                                                 tag_11_contents_size);
1839                                 rc = -EIO;
1840                                 goto out_wipe_list;
1841                         }
1842                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1843                                         sig_tmp_space, tag_11_contents_size);
1844                         new_auth_tok->token.password.signature[
1845                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1846                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1847                         break;
1848                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1849                         rc = parse_tag_1_packet(crypt_stat,
1850                                                 (unsigned char *)&src[i],
1851                                                 &auth_tok_list, &new_auth_tok,
1852                                                 &packet_size, max_packet_size);
1853                         if (rc) {
1854                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1855                                                 "tag 1 packet\n");
1856                                 rc = -EIO;
1857                                 goto out_wipe_list;
1858                         }
1859                         i += packet_size;
1860                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1861                         break;
1862                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1863                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1864                                         "(Tag 11 not allowed by itself)\n");
1865                         rc = -EIO;
1866                         goto out_wipe_list;
1867                 default:
1868                         ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1869                                         "of the file header; hex value of "
1870                                         "character is [0x%.2x]\n", i, src[i]);
1871                         next_packet_is_auth_tok_packet = 0;
1872                 }
1873         }
1874         if (list_empty(&auth_tok_list)) {
1875                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1876                        "eCryptfs file; this is not supported in this version "
1877                        "of the eCryptfs kernel module\n");
1878                 rc = -EINVAL;
1879                 goto out;
1880         }
1881         /* auth_tok_list contains the set of authentication tokens
1882          * parsed from the metadata. We need to find a matching
1883          * authentication token that has the secret component(s)
1884          * necessary to decrypt the EFEK in the auth_tok parsed from
1885          * the metadata. There may be several potential matches, but
1886          * just one will be sufficient to decrypt to get the FEK. */
1887 find_next_matching_auth_tok:
1888         found_auth_tok = 0;
1889         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1890                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1891                 if (unlikely(ecryptfs_verbosity > 0)) {
1892                         ecryptfs_printk(KERN_DEBUG,
1893                                         "Considering cadidate auth tok:\n");
1894                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1895                 }
1896                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1897                                                candidate_auth_tok);
1898                 if (rc) {
1899                         printk(KERN_ERR
1900                                "Unrecognized candidate auth tok type: [%d]\n",
1901                                candidate_auth_tok->token_type);
1902                         rc = -EINVAL;
1903                         goto out_wipe_list;
1904                 }
1905                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1906                                                &matching_auth_tok,
1907                                                crypt_stat->mount_crypt_stat,
1908                                                candidate_auth_tok_sig);
1909                 if (!rc) {
1910                         found_auth_tok = 1;
1911                         goto found_matching_auth_tok;
1912                 }
1913         }
1914         if (!found_auth_tok) {
1915                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1916                                 "authentication token\n");
1917                 rc = -EIO;
1918                 goto out_wipe_list;
1919         }
1920 found_matching_auth_tok:
1921         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1922                 memcpy(&(candidate_auth_tok->token.private_key),
1923                        &(matching_auth_tok->token.private_key),
1924                        sizeof(struct ecryptfs_private_key));
1925                 up_write(&(auth_tok_key->sem));
1926                 key_put(auth_tok_key);
1927                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1928                                                        crypt_stat);
1929         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1930                 memcpy(&(candidate_auth_tok->token.password),
1931                        &(matching_auth_tok->token.password),
1932                        sizeof(struct ecryptfs_password));
1933                 up_write(&(auth_tok_key->sem));
1934                 key_put(auth_tok_key);
1935                 rc = decrypt_passphrase_encrypted_session_key(
1936                         candidate_auth_tok, crypt_stat);
1937         } else {
1938                 up_write(&(auth_tok_key->sem));
1939                 key_put(auth_tok_key);
1940                 rc = -EINVAL;
1941         }
1942         if (rc) {
1943                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1944
1945                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1946                                 "session key for authentication token with sig "
1947                                 "[%.*s]; rc = [%d]. Removing auth tok "
1948                                 "candidate from the list and searching for "
1949                                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1950                                 candidate_auth_tok_sig, rc);
1951                 list_for_each_entry_safe(auth_tok_list_item,
1952                                          auth_tok_list_item_tmp,
1953                                          &auth_tok_list, list) {
1954                         if (candidate_auth_tok
1955                             == &auth_tok_list_item->auth_tok) {
1956                                 list_del(&auth_tok_list_item->list);
1957                                 kmem_cache_free(
1958                                         ecryptfs_auth_tok_list_item_cache,
1959                                         auth_tok_list_item);
1960                                 goto find_next_matching_auth_tok;
1961                         }
1962                 }
1963                 BUG();
1964         }
1965         rc = ecryptfs_compute_root_iv(crypt_stat);
1966         if (rc) {
1967                 ecryptfs_printk(KERN_ERR, "Error computing "
1968                                 "the root IV\n");
1969                 goto out_wipe_list;
1970         }
1971         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1972         if (rc) {
1973                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1974                                 "context for cipher [%s]; rc = [%d]\n",
1975                                 crypt_stat->cipher, rc);
1976         }
1977 out_wipe_list:
1978         wipe_auth_tok_list(&auth_tok_list);
1979 out:
1980         return rc;
1981 }
1982
1983 static int
1984 pki_encrypt_session_key(struct key *auth_tok_key,
1985                         struct ecryptfs_auth_tok *auth_tok,
1986                         struct ecryptfs_crypt_stat *crypt_stat,
1987                         struct ecryptfs_key_record *key_rec)
1988 {
1989         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1990         char *payload = NULL;
1991         size_t payload_len = 0;
1992         struct ecryptfs_message *msg;
1993         int rc;
1994
1995         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1996                                  ecryptfs_code_for_cipher_string(
1997                                          crypt_stat->cipher,
1998                                          crypt_stat->key_size),
1999                                  crypt_stat, &payload, &payload_len);
2000         up_write(&(auth_tok_key->sem));
2001         key_put(auth_tok_key);
2002         if (rc) {
2003                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
2004                 goto out;
2005         }
2006         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
2007         if (rc) {
2008                 ecryptfs_printk(KERN_ERR, "Error sending message to "
2009                                 "ecryptfsd: %d\n", rc);
2010                 goto out;
2011         }
2012         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2013         if (rc) {
2014                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2015                                 "from the user space daemon\n");
2016                 rc = -EIO;
2017                 goto out;
2018         }
2019         rc = parse_tag_67_packet(key_rec, msg);
2020         if (rc)
2021                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2022         kfree(msg);
2023 out:
2024         kfree(payload);
2025         return rc;
2026 }
2027 /**
2028  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2029  * @dest: Buffer into which to write the packet
2030  * @remaining_bytes: Maximum number of bytes that can be writtn
2031  * @auth_tok_key: The authentication token key to unlock and put when done with
2032  *                @auth_tok
2033  * @auth_tok: The authentication token used for generating the tag 1 packet
2034  * @crypt_stat: The cryptographic context
2035  * @key_rec: The key record struct for the tag 1 packet
2036  * @packet_size: This function will write the number of bytes that end
2037  *               up constituting the packet; set to zero on error
2038  *
2039  * Returns zero on success; non-zero on error.
2040  */
2041 static int
2042 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2043                    struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2044                    struct ecryptfs_crypt_stat *crypt_stat,
2045                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2046 {
2047         size_t i;
2048         size_t encrypted_session_key_valid = 0;
2049         size_t packet_size_length;
2050         size_t max_packet_size;
2051         int rc = 0;
2052
2053         (*packet_size) = 0;
2054         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2055                           ECRYPTFS_SIG_SIZE);
2056         encrypted_session_key_valid = 0;
2057         for (i = 0; i < crypt_stat->key_size; i++)
2058                 encrypted_session_key_valid |=
2059                         auth_tok->session_key.encrypted_key[i];
2060         if (encrypted_session_key_valid) {
2061                 memcpy(key_rec->enc_key,
2062                        auth_tok->session_key.encrypted_key,
2063                        auth_tok->session_key.encrypted_key_size);
2064                 up_write(&(auth_tok_key->sem));
2065                 key_put(auth_tok_key);
2066                 goto encrypted_session_key_set;
2067         }
2068         if (auth_tok->session_key.encrypted_key_size == 0)
2069                 auth_tok->session_key.encrypted_key_size =
2070                         auth_tok->token.private_key.key_size;
2071         rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2072                                      key_rec);
2073         if (rc) {
2074                 printk(KERN_ERR "Failed to encrypt session key via a key "
2075                        "module; rc = [%d]\n", rc);
2076                 goto out;
2077         }
2078         if (ecryptfs_verbosity > 0) {
2079                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2080                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2081         }
2082 encrypted_session_key_set:
2083         /* This format is inspired by OpenPGP; see RFC 2440
2084          * packet tag 1 */
2085         max_packet_size = (1                         /* Tag 1 identifier */
2086                            + 3                       /* Max Tag 1 packet size */
2087                            + 1                       /* Version */
2088                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
2089                            + 1                       /* Cipher identifier */
2090                            + key_rec->enc_key_size); /* Encrypted key size */
2091         if (max_packet_size > (*remaining_bytes)) {
2092                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2093                        "need up to [%td] bytes, but there are only [%td] "
2094                        "available\n", max_packet_size, (*remaining_bytes));
2095                 rc = -EINVAL;
2096                 goto out;
2097         }
2098         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2099         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2100                                           (max_packet_size - 4),
2101                                           &packet_size_length);
2102         if (rc) {
2103                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2104                                 "header; cannot generate packet length\n");
2105                 goto out;
2106         }
2107         (*packet_size) += packet_size_length;
2108         dest[(*packet_size)++] = 0x03; /* version 3 */
2109         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2110         (*packet_size) += ECRYPTFS_SIG_SIZE;
2111         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2112         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2113                key_rec->enc_key_size);
2114         (*packet_size) += key_rec->enc_key_size;
2115 out:
2116         if (rc)
2117                 (*packet_size) = 0;
2118         else
2119                 (*remaining_bytes) -= (*packet_size);
2120         return rc;
2121 }
2122
2123 /**
2124  * write_tag_11_packet
2125  * @dest: Target into which Tag 11 packet is to be written
2126  * @remaining_bytes: Maximum packet length
2127  * @contents: Byte array of contents to copy in
2128  * @contents_length: Number of bytes in contents
2129  * @packet_length: Length of the Tag 11 packet written; zero on error
2130  *
2131  * Returns zero on success; non-zero on error.
2132  */
2133 static int
2134 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2135                     size_t contents_length, size_t *packet_length)
2136 {
2137         size_t packet_size_length;
2138         size_t max_packet_size;
2139         int rc = 0;
2140
2141         (*packet_length) = 0;
2142         /* This format is inspired by OpenPGP; see RFC 2440
2143          * packet tag 11 */
2144         max_packet_size = (1                   /* Tag 11 identifier */
2145                            + 3                 /* Max Tag 11 packet size */
2146                            + 1                 /* Binary format specifier */
2147                            + 1                 /* Filename length */
2148                            + 8                 /* Filename ("_CONSOLE") */
2149                            + 4                 /* Modification date */
2150                            + contents_length); /* Literal data */
2151         if (max_packet_size > (*remaining_bytes)) {
2152                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2153                        "need up to [%td] bytes, but there are only [%td] "
2154                        "available\n", max_packet_size, (*remaining_bytes));
2155                 rc = -EINVAL;
2156                 goto out;
2157         }
2158         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2159         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2160                                           (max_packet_size - 4),
2161                                           &packet_size_length);
2162         if (rc) {
2163                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2164                        "generate packet length. rc = [%d]\n", rc);
2165                 goto out;
2166         }
2167         (*packet_length) += packet_size_length;
2168         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2169         dest[(*packet_length)++] = 8;
2170         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2171         (*packet_length) += 8;
2172         memset(&dest[(*packet_length)], 0x00, 4);
2173         (*packet_length) += 4;
2174         memcpy(&dest[(*packet_length)], contents, contents_length);
2175         (*packet_length) += contents_length;
2176  out:
2177         if (rc)
2178                 (*packet_length) = 0;
2179         else
2180                 (*remaining_bytes) -= (*packet_length);
2181         return rc;
2182 }
2183
2184 /**
2185  * write_tag_3_packet
2186  * @dest: Buffer into which to write the packet
2187  * @remaining_bytes: Maximum number of bytes that can be written
2188  * @auth_tok: Authentication token
2189  * @crypt_stat: The cryptographic context
2190  * @key_rec: encrypted key
2191  * @packet_size: This function will write the number of bytes that end
2192  *               up constituting the packet; set to zero on error
2193  *
2194  * Returns zero on success; non-zero on error.
2195  */
2196 static int
2197 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2198                    struct ecryptfs_auth_tok *auth_tok,
2199                    struct ecryptfs_crypt_stat *crypt_stat,
2200                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2201 {
2202         size_t i;
2203         size_t encrypted_session_key_valid = 0;
2204         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2205         struct scatterlist dst_sg[2];
2206         struct scatterlist src_sg[2];
2207         struct mutex *tfm_mutex = NULL;
2208         u8 cipher_code;
2209         size_t packet_size_length;
2210         size_t max_packet_size;
2211         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2212                 crypt_stat->mount_crypt_stat;
2213         struct crypto_skcipher *tfm;
2214         struct skcipher_request *req;
2215         int rc = 0;
2216
2217         (*packet_size) = 0;
2218         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2219                           ECRYPTFS_SIG_SIZE);
2220         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2221                                                         crypt_stat->cipher);
2222         if (unlikely(rc)) {
2223                 printk(KERN_ERR "Internal error whilst attempting to get "
2224                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2225                        crypt_stat->cipher, rc);
2226                 goto out;
2227         }
2228         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2229                 printk(KERN_WARNING "No key size specified at mount; "
2230                        "defaulting to [%d]\n",
2231                        crypto_skcipher_default_keysize(tfm));
2232                 mount_crypt_stat->global_default_cipher_key_size =
2233                         crypto_skcipher_default_keysize(tfm);
2234         }
2235         if (crypt_stat->key_size == 0)
2236                 crypt_stat->key_size =
2237                         mount_crypt_stat->global_default_cipher_key_size;
2238         if (auth_tok->session_key.encrypted_key_size == 0)
2239                 auth_tok->session_key.encrypted_key_size =
2240                         crypt_stat->key_size;
2241         if (crypt_stat->key_size == 24
2242             && strcmp("aes", crypt_stat->cipher) == 0) {
2243                 memset((crypt_stat->key + 24), 0, 8);
2244                 auth_tok->session_key.encrypted_key_size = 32;
2245         } else
2246                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2247         key_rec->enc_key_size =
2248                 auth_tok->session_key.encrypted_key_size;
2249         encrypted_session_key_valid = 0;
2250         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2251                 encrypted_session_key_valid |=
2252                         auth_tok->session_key.encrypted_key[i];
2253         if (encrypted_session_key_valid) {
2254                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2255                                 "using auth_tok->session_key.encrypted_key, "
2256                                 "where key_rec->enc_key_size = [%zd]\n",
2257                                 key_rec->enc_key_size);
2258                 memcpy(key_rec->enc_key,
2259                        auth_tok->session_key.encrypted_key,
2260                        key_rec->enc_key_size);
2261                 goto encrypted_session_key_set;
2262         }
2263         if (auth_tok->token.password.flags &
2264             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2265                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2266                                 "session key encryption key of size [%d]\n",
2267                                 auth_tok->token.password.
2268                                 session_key_encryption_key_bytes);
2269                 memcpy(session_key_encryption_key,
2270                        auth_tok->token.password.session_key_encryption_key,
2271                        crypt_stat->key_size);
2272                 ecryptfs_printk(KERN_DEBUG,
2273                                 "Cached session key encryption key:\n");
2274                 if (ecryptfs_verbosity > 0)
2275                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2276         }
2277         if (unlikely(ecryptfs_verbosity > 0)) {
2278                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2279                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2280         }
2281         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2282                                  src_sg, 2);
2283         if (rc < 1 || rc > 2) {
2284                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2285                                 "for crypt_stat session key; expected rc = 1; "
2286                                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2287                                 rc, key_rec->enc_key_size);
2288                 rc = -ENOMEM;
2289                 goto out;
2290         }
2291         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2292                                  dst_sg, 2);
2293         if (rc < 1 || rc > 2) {
2294                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2295                                 "for crypt_stat encrypted session key; "
2296                                 "expected rc = 1; got rc = [%d]. "
2297                                 "key_rec->enc_key_size = [%zd]\n", rc,
2298                                 key_rec->enc_key_size);
2299                 rc = -ENOMEM;
2300                 goto out;
2301         }
2302         mutex_lock(tfm_mutex);
2303         rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2304                                     crypt_stat->key_size);
2305         if (rc < 0) {
2306                 mutex_unlock(tfm_mutex);
2307                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2308                                 "context; rc = [%d]\n", rc);
2309                 goto out;
2310         }
2311
2312         req = skcipher_request_alloc(tfm, GFP_KERNEL);
2313         if (!req) {
2314                 mutex_unlock(tfm_mutex);
2315                 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2316                                 "attempting to skcipher_request_alloc for "
2317                                 "%s\n", crypto_skcipher_driver_name(tfm));
2318                 rc = -ENOMEM;
2319                 goto out;
2320         }
2321
2322         skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2323                                       NULL, NULL);
2324
2325         rc = 0;
2326         ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2327                         crypt_stat->key_size);
2328         skcipher_request_set_crypt(req, src_sg, dst_sg,
2329                                    (*key_rec).enc_key_size, NULL);
2330         rc = crypto_skcipher_encrypt(req);
2331         mutex_unlock(tfm_mutex);
2332         skcipher_request_free(req);
2333         if (rc) {
2334                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2335                 goto out;
2336         }
2337         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2338         if (ecryptfs_verbosity > 0) {
2339                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2340                                 key_rec->enc_key_size);
2341                 ecryptfs_dump_hex(key_rec->enc_key,
2342                                   key_rec->enc_key_size);
2343         }
2344 encrypted_session_key_set:
2345         /* This format is inspired by OpenPGP; see RFC 2440
2346          * packet tag 3 */
2347         max_packet_size = (1                         /* Tag 3 identifier */
2348                            + 3                       /* Max Tag 3 packet size */
2349                            + 1                       /* Version */
2350                            + 1                       /* Cipher code */
2351                            + 1                       /* S2K specifier */
2352                            + 1                       /* Hash identifier */
2353                            + ECRYPTFS_SALT_SIZE      /* Salt */
2354                            + 1                       /* Hash iterations */
2355                            + key_rec->enc_key_size); /* Encrypted key size */
2356         if (max_packet_size > (*remaining_bytes)) {
2357                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2358                        "there are only [%td] available\n", max_packet_size,
2359                        (*remaining_bytes));
2360                 rc = -EINVAL;
2361                 goto out;
2362         }
2363         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2364         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2365          * to get the number of octets in the actual Tag 3 packet */
2366         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2367                                           (max_packet_size - 4),
2368                                           &packet_size_length);
2369         if (rc) {
2370                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2371                        "generate packet length. rc = [%d]\n", rc);
2372                 goto out;
2373         }
2374         (*packet_size) += packet_size_length;
2375         dest[(*packet_size)++] = 0x04; /* version 4 */
2376         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2377          * specified with strings */
2378         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2379                                                       crypt_stat->key_size);
2380         if (cipher_code == 0) {
2381                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2382                                 "cipher [%s]\n", crypt_stat->cipher);
2383                 rc = -EINVAL;
2384                 goto out;
2385         }
2386         dest[(*packet_size)++] = cipher_code;
2387         dest[(*packet_size)++] = 0x03;  /* S2K */
2388         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2389         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2390                ECRYPTFS_SALT_SIZE);
2391         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2392         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2393         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2394                key_rec->enc_key_size);
2395         (*packet_size) += key_rec->enc_key_size;
2396 out:
2397         if (rc)
2398                 (*packet_size) = 0;
2399         else
2400                 (*remaining_bytes) -= (*packet_size);
2401         return rc;
2402 }
2403
2404 struct kmem_cache *ecryptfs_key_record_cache;
2405
2406 /**
2407  * ecryptfs_generate_key_packet_set
2408  * @dest_base: Virtual address from which to write the key record set
2409  * @crypt_stat: The cryptographic context from which the
2410  *              authentication tokens will be retrieved
2411  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2412  *                   for the global parameters
2413  * @len: The amount written
2414  * @max: The maximum amount of data allowed to be written
2415  *
2416  * Generates a key packet set and writes it to the virtual address
2417  * passed in.
2418  *
2419  * Returns zero on success; non-zero on error.
2420  */
2421 int
2422 ecryptfs_generate_key_packet_set(char *dest_base,
2423                                  struct ecryptfs_crypt_stat *crypt_stat,
2424                                  struct dentry *ecryptfs_dentry, size_t *len,
2425                                  size_t max)
2426 {
2427         struct ecryptfs_auth_tok *auth_tok;
2428         struct key *auth_tok_key = NULL;
2429         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2430                 &ecryptfs_superblock_to_private(
2431                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2432         size_t written;
2433         struct ecryptfs_key_record *key_rec;
2434         struct ecryptfs_key_sig *key_sig;
2435         int rc = 0;
2436
2437         (*len) = 0;
2438         mutex_lock(&crypt_stat->keysig_list_mutex);
2439         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2440         if (!key_rec) {
2441                 rc = -ENOMEM;
2442                 goto out;
2443         }
2444         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2445                             crypt_stat_list) {
2446                 memset(key_rec, 0, sizeof(*key_rec));
2447                 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2448                                                            &auth_tok,
2449                                                            mount_crypt_stat,
2450                                                            key_sig->keysig);
2451                 if (rc) {
2452                         printk(KERN_WARNING "Unable to retrieve auth tok with "
2453                                "sig = [%s]\n", key_sig->keysig);
2454                         rc = process_find_global_auth_tok_for_sig_err(rc);
2455                         goto out_free;
2456                 }
2457                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2458                         rc = write_tag_3_packet((dest_base + (*len)),
2459                                                 &max, auth_tok,
2460                                                 crypt_stat, key_rec,
2461                                                 &written);
2462                         up_write(&(auth_tok_key->sem));
2463                         key_put(auth_tok_key);
2464                         if (rc) {
2465                                 ecryptfs_printk(KERN_WARNING, "Error "
2466                                                 "writing tag 3 packet\n");
2467                                 goto out_free;
2468                         }
2469                         (*len) += written;
2470                         /* Write auth tok signature packet */
2471                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2472                                                  key_rec->sig,
2473                                                  ECRYPTFS_SIG_SIZE, &written);
2474                         if (rc) {
2475                                 ecryptfs_printk(KERN_ERR, "Error writing "
2476                                                 "auth tok signature packet\n");
2477                                 goto out_free;
2478                         }
2479                         (*len) += written;
2480                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2481                         rc = write_tag_1_packet(dest_base + (*len), &max,
2482                                                 auth_tok_key, auth_tok,
2483                                                 crypt_stat, key_rec, &written);
2484                         if (rc) {
2485                                 ecryptfs_printk(KERN_WARNING, "Error "
2486                                                 "writing tag 1 packet\n");
2487                                 goto out_free;
2488                         }
2489                         (*len) += written;
2490                 } else {
2491                         up_write(&(auth_tok_key->sem));
2492                         key_put(auth_tok_key);
2493                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2494                                         "authentication token type\n");
2495                         rc = -EINVAL;
2496                         goto out_free;
2497                 }
2498         }
2499         if (likely(max > 0)) {
2500                 dest_base[(*len)] = 0x00;
2501         } else {
2502                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2503                 rc = -EIO;
2504         }
2505 out_free:
2506         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2507 out:
2508         if (rc)
2509                 (*len) = 0;
2510         mutex_unlock(&crypt_stat->keysig_list_mutex);
2511         return rc;
2512 }
2513
2514 struct kmem_cache *ecryptfs_key_sig_cache;
2515
2516 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2517 {
2518         struct ecryptfs_key_sig *new_key_sig;
2519
2520         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2521         if (!new_key_sig) {
2522                 printk(KERN_ERR
2523                        "Error allocating from ecryptfs_key_sig_cache\n");
2524                 return -ENOMEM;
2525         }
2526         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2527         new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2528         /* Caller must hold keysig_list_mutex */
2529         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2530
2531         return 0;
2532 }
2533
2534 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2535
2536 int
2537 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2538                              char *sig, u32 global_auth_tok_flags)
2539 {
2540         struct ecryptfs_global_auth_tok *new_auth_tok;
2541         int rc = 0;
2542
2543         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2544                                         GFP_KERNEL);
2545         if (!new_auth_tok) {
2546                 rc = -ENOMEM;
2547                 printk(KERN_ERR "Error allocating from "
2548                        "ecryptfs_global_auth_tok_cache\n");
2549                 goto out;
2550         }
2551         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2552         new_auth_tok->flags = global_auth_tok_flags;
2553         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2554         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2555         list_add(&new_auth_tok->mount_crypt_stat_list,
2556                  &mount_crypt_stat->global_auth_tok_list);
2557         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2558 out:
2559         return rc;
2560 }
2561