fs/ecryptfs/keystore.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  * In-kernel key management code.  Includes functions to parse and
   4  * write authentication token-related packets with the underlying
   5  * file.
   6  *
   7  * Copyright (C) 2004-2006 International Business Machines Corp.
   8  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
   9  *              Michael C. Thompson <mcthomps@us.ibm.com>
  10  *              Trevor S. Highland <trevor.highland@gmail.com>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  25  * 02111-1307, USA.
  26  */
  27
  28 #include <linux/string.h>
  29 #include <linux/syscalls.h>
  30 #include <linux/pagemap.h>
  31 #include <linux/key.h>
  32 #include <linux/random.h>
  33 #include <linux/crypto.h>
  34 #include <linux/scatterlist.h>
  35 #include <linux/slab.h>
  36 #include "ecryptfs_kernel.h"
  37
  38 /**
  39  * request_key returned an error instead of a valid key address;
  40  * determine the type of error, make appropriate log entries, and
  41  * return an error code.
  42  */
  43 static int process_request_key_err(long err_code)
  44 {
  45         int rc = 0;
  46
  47         switch (err_code) {
  48         case -ENOKEY:
  49                 ecryptfs_printk(KERN_WARNING, "No key\n");
  50                 rc = -ENOENT;
  51                 break;
  52         case -EKEYEXPIRED:
  53                 ecryptfs_printk(KERN_WARNING, "Key expired\n");
  54                 rc = -ETIME;
  55                 break;
  56         case -EKEYREVOKED:
  57                 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
  58                 rc = -EINVAL;
  59                 break;
  60         default:
  61                 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
  62                                 "[0x%.16x]\n", err_code);
  63                 rc = -EINVAL;
  64         }
  65         return rc;
  66 }
  67
  68 /**
  69  * ecryptfs_parse_packet_length
  70  * @data: Pointer to memory containing length at offset
  71  * @size: This function writes the decoded size to this memory
  72  *        address; zero on error
  73  * @length_size: The number of bytes occupied by the encoded length
  74  *
  75  * Returns zero on success; non-zero on error
  76  */
  77 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
  78                                  size_t *length_size)
  79 {
  80         int rc = 0;
  81
  82         (*length_size) = 0;
  83         (*size) = 0;
  84         if (data[0] < 192) {
  85                 /* One-byte length */
  86                 (*size) = (unsigned char)data[0];
  87                 (*length_size) = 1;
  88         } else if (data[0] < 224) {
  89                 /* Two-byte length */
  90                 (*size) = (((unsigned char)(data[0]) - 192) * 256);
  91                 (*size) += ((unsigned char)(data[1]) + 192);
  92                 (*length_size) = 2;
  93         } else if (data[0] == 255) {
  94                 /* Five-byte length; we're not supposed to see this */
  95                 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
  96                                 "supported\n");
  97                 rc = -EINVAL;
  98                 goto out;
  99         } else {
 100                 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
 101                 rc = -EINVAL;
 102                 goto out;
 103         }
 104 out:
 105         return rc;
 106 }
 107
 108 /**
 109  * ecryptfs_write_packet_length
 110  * @dest: The byte array target into which to write the length. Must
 111  *        have at least 5 bytes allocated.
 112  * @size: The length to write.
 113  * @packet_size_length: The number of bytes used to encode the packet
 114  *                      length is written to this address.
 115  *
 116  * Returns zero on success; non-zero on error.
 117  */
 118 int ecryptfs_write_packet_length(char *dest, size_t size,
 119                                  size_t *packet_size_length)
 120 {
 121         int rc = 0;
 122
 123         if (size < 192) {
 124                 dest[0] = size;
 125                 (*packet_size_length) = 1;
 126         } else if (size < 65536) {
 127                 dest[0] = (((size - 192) / 256) + 192);
 128                 dest[1] = ((size - 192) % 256);
 129                 (*packet_size_length) = 2;
 130         } else {
 131                 rc = -EINVAL;
 132                 ecryptfs_printk(KERN_WARNING,
 133                                 "Unsupported packet size: [%d]\n", size);
 134         }
 135         return rc;
 136 }
 137
 138 static int
 139 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
 140                     char **packet, size_t *packet_len)
 141 {
 142         size_t i = 0;
 143         size_t data_len;
 144         size_t packet_size_len;
 145         char *message;
 146         int rc;
 147
 148         /*
 149          *              ***** TAG 64 Packet Format *****
 150          *    | Content Type                       | 1 byte       |
 151          *    | Key Identifier Size                | 1 or 2 bytes |
 152          *    | Key Identifier                     | arbitrary    |
 153          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 154          *    | Encrypted File Encryption Key      | arbitrary    |
 155          */
 156         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
 157                     + session_key->encrypted_key_size);
 158         *packet = kmalloc(data_len, GFP_KERNEL);
 159         message = *packet;
 160         if (!message) {
 161                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 162                 rc = -ENOMEM;
 163                 goto out;
 164         }
 165         message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
 166         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 167                                           &packet_size_len);
 168         if (rc) {
 169                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 170                                 "header; cannot generate packet length\n");
 171                 goto out;
 172         }
 173         i += packet_size_len;
 174         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 175         i += ECRYPTFS_SIG_SIZE_HEX;
 176         rc = ecryptfs_write_packet_length(&message[i],
 177                                           session_key->encrypted_key_size,
 178                                           &packet_size_len);
 179         if (rc) {
 180                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 181                                 "header; cannot generate packet length\n");
 182                 goto out;
 183         }
 184         i += packet_size_len;
 185         memcpy(&message[i], session_key->encrypted_key,
 186                session_key->encrypted_key_size);
 187         i += session_key->encrypted_key_size;
 188         *packet_len = i;
 189 out:
 190         return rc;
 191 }
 192
 193 static int
 194 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
 195                     struct ecryptfs_message *msg)
 196 {
 197         size_t i = 0;
 198         char *data;
 199         size_t data_len;
 200         size_t m_size;
 201         size_t message_len;
 202         u16 checksum = 0;
 203         u16 expected_checksum = 0;
 204         int rc;
 205
 206         /*
 207          *              ***** TAG 65 Packet Format *****
 208          *         | Content Type             | 1 byte       |
 209          *         | Status Indicator         | 1 byte       |
 210          *         | File Encryption Key Size | 1 or 2 bytes |
 211          *         | File Encryption Key      | arbitrary    |
 212          */
 213         message_len = msg->data_len;
 214         data = msg->data;
 215         if (message_len < 4) {
 216                 rc = -EIO;
 217                 goto out;
 218         }
 219         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
 220                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
 221                 rc = -EIO;
 222                 goto out;
 223         }
 224         if (data[i++]) {
 225                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
 226                                 "[%d]\n", data[i-1]);
 227                 rc = -EIO;
 228                 goto out;
 229         }
 230         rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
 231         if (rc) {
 232                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 233                                 "rc = [%d]\n", rc);
 234                 goto out;
 235         }
 236         i += data_len;
 237         if (message_len < (i + m_size)) {
 238                 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
 239                                 "is shorter than expected\n");
 240                 rc = -EIO;
 241                 goto out;
 242         }
 243         if (m_size < 3) {
 244                 ecryptfs_printk(KERN_ERR,
 245                                 "The decrypted key is not long enough to "
 246                                 "include a cipher code and checksum\n");
 247                 rc = -EIO;
 248                 goto out;
 249         }
 250         *cipher_code = data[i++];
 251         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
 252         session_key->decrypted_key_size = m_size - 3;
 253         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
 254                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
 255                                 "the maximum key size [%d]\n",
 256                                 session_key->decrypted_key_size,
 257                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 258                 rc = -EIO;
 259                 goto out;
 260         }
 261         memcpy(session_key->decrypted_key, &data[i],
 262                session_key->decrypted_key_size);
 263         i += session_key->decrypted_key_size;
 264         expected_checksum += (unsigned char)(data[i++]) << 8;
 265         expected_checksum += (unsigned char)(data[i++]);
 266         for (i = 0; i < session_key->decrypted_key_size; i++)
 267                 checksum += session_key->decrypted_key[i];
 268         if (expected_checksum != checksum) {
 269                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
 270                                 "encryption  key; expected [%x]; calculated "
 271                                 "[%x]\n", expected_checksum, checksum);
 272                 rc = -EIO;
 273         }
 274 out:
 275         return rc;
 276 }
 277
 278
 279 static int
 280 write_tag_66_packet(char *signature, u8 cipher_code,
 281                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
 282                     size_t *packet_len)
 283 {
 284         size_t i = 0;
 285         size_t j;
 286         size_t data_len;
 287         size_t checksum = 0;
 288         size_t packet_size_len;
 289         char *message;
 290         int rc;
 291
 292         /*
 293          *              ***** TAG 66 Packet Format *****
 294          *         | Content Type             | 1 byte       |
 295          *         | Key Identifier Size      | 1 or 2 bytes |
 296          *         | Key Identifier           | arbitrary    |
 297          *         | File Encryption Key Size | 1 or 2 bytes |
 298          *         | File Encryption Key      | arbitrary    |
 299          */
 300         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
 301         *packet = kmalloc(data_len, GFP_KERNEL);
 302         message = *packet;
 303         if (!message) {
 304                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 305                 rc = -ENOMEM;
 306                 goto out;
 307         }
 308         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
 309         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 310                                           &packet_size_len);
 311         if (rc) {
 312                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 313                                 "header; cannot generate packet length\n");
 314                 goto out;
 315         }
 316         i += packet_size_len;
 317         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 318         i += ECRYPTFS_SIG_SIZE_HEX;
 319         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
 320         rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
 321                                           &packet_size_len);
 322         if (rc) {
 323                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 324                                 "header; cannot generate packet length\n");
 325                 goto out;
 326         }
 327         i += packet_size_len;
 328         message[i++] = cipher_code;
 329         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
 330         i += crypt_stat->key_size;
 331         for (j = 0; j < crypt_stat->key_size; j++)
 332                 checksum += crypt_stat->key[j];
 333         message[i++] = (checksum / 256) % 256;
 334         message[i++] = (checksum % 256);
 335         *packet_len = i;
 336 out:
 337         return rc;
 338 }
 339
 340 static int
 341 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
 342                     struct ecryptfs_message *msg)
 343 {
 344         size_t i = 0;
 345         char *data;
 346         size_t data_len;
 347         size_t message_len;
 348         int rc;
 349
 350         /*
 351          *              ***** TAG 65 Packet Format *****
 352          *    | Content Type                       | 1 byte       |
 353          *    | Status Indicator                   | 1 byte       |
 354          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 355          *    | Encrypted File Encryption Key      | arbitrary    |
 356          */
 357         message_len = msg->data_len;
 358         data = msg->data;
 359         /* verify that everything through the encrypted FEK size is present */
 360         if (message_len < 4) {
 361                 rc = -EIO;
 362                 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
 363                        "message length is [%d]\n", __func__, message_len, 4);
 364                 goto out;
 365         }
 366         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
 367                 rc = -EIO;
 368                 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
 369                        __func__);
 370                 goto out;
 371         }
 372         if (data[i++]) {
 373                 rc = -EIO;
 374                 printk(KERN_ERR "%s: Status indicator has non zero "
 375                        "value [%d]\n", __func__, data[i-1]);
 376
 377                 goto out;
 378         }
 379         rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
 380                                           &data_len);
 381         if (rc) {
 382                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 383                                 "rc = [%d]\n", rc);
 384                 goto out;
 385         }
 386         i += data_len;
 387         if (message_len < (i + key_rec->enc_key_size)) {
 388                 rc = -EIO;
 389                 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
 390                        __func__, message_len, (i + key_rec->enc_key_size));
 391                 goto out;
 392         }
 393         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 394                 rc = -EIO;
 395                 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
 396                        "the maximum key size [%d]\n", __func__,
 397                        key_rec->enc_key_size,
 398                        ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 399                 goto out;
 400         }
 401         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
 402 out:
 403         return rc;
 404 }
 405
 406 static int
 407 ecryptfs_find_global_auth_tok_for_sig(
 408         struct ecryptfs_global_auth_tok **global_auth_tok,
 409         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 410 {
 411         struct ecryptfs_global_auth_tok *walker;
 412         int rc = 0;
 413
 414         (*global_auth_tok) = NULL;
 415         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 416         list_for_each_entry(walker,
 417                             &mount_crypt_stat->global_auth_tok_list,
 418                             mount_crypt_stat_list) {
 419                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX) == 0) {
 420                         rc = key_validate(walker->global_auth_tok_key);
 421                         if (!rc)
 422                                 (*global_auth_tok) = walker;
 423                         goto out;
 424                 }
 425         }
 426         rc = -EINVAL;
 427 out:
 428         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 429         return rc;
 430 }
 431
 432 /**
 433  * ecryptfs_find_auth_tok_for_sig
 434  * @auth_tok: Set to the matching auth_tok; NULL if not found
 435  * @crypt_stat: inode crypt_stat crypto context
 436  * @sig: Sig of auth_tok to find
 437  *
 438  * For now, this function simply looks at the registered auth_tok's
 439  * linked off the mount_crypt_stat, so all the auth_toks that can be
 440  * used must be registered at mount time. This function could
 441  * potentially try a lot harder to find auth_tok's (e.g., by calling
 442  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
 443  * that static registration of auth_tok's will no longer be necessary.
 444  *
 445  * Returns zero on no error; non-zero on error
 446  */
 447 static int
 448 ecryptfs_find_auth_tok_for_sig(
 449         struct key **auth_tok_key,
 450         struct ecryptfs_auth_tok **auth_tok,
 451         struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 452         char *sig)
 453 {
 454         struct ecryptfs_global_auth_tok *global_auth_tok;
 455         int rc = 0;
 456
 457         (*auth_tok_key) = NULL;
 458         (*auth_tok) = NULL;
 459         if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
 460                                                   mount_crypt_stat, sig)) {
 461
 462                 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
 463                                                        sig);
 464         } else
 465                 (*auth_tok) = global_auth_tok->global_auth_tok;
 466         return rc;
 467 }
 468
 469 /**
 470  * write_tag_70_packet can gobble a lot of stack space. We stuff most
 471  * of the function's parameters in a kmalloc'd struct to help reduce
 472  * eCryptfs' overall stack usage.
 473  */
 474 struct ecryptfs_write_tag_70_packet_silly_stack {
 475         u8 cipher_code;
 476         size_t max_packet_size;
 477         size_t packet_size_len;
 478         size_t block_aligned_filename_size;
 479         size_t block_size;
 480         size_t i;
 481         size_t j;
 482         size_t num_rand_bytes;
 483         struct mutex *tfm_mutex;
 484         char *block_aligned_filename;
 485         struct ecryptfs_auth_tok *auth_tok;
 486         struct scatterlist src_sg;
 487         struct scatterlist dst_sg;
 488         struct blkcipher_desc desc;
 489         char iv[ECRYPTFS_MAX_IV_BYTES];
 490         char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 491         char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 492         struct hash_desc hash_desc;
 493         struct scatterlist hash_sg;
 494 };
 495
 496 /**
 497  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
 498  * @filename: NULL-terminated filename string
 499  *
 500  * This is the simplest mechanism for achieving filename encryption in
 501  * eCryptfs. It encrypts the given filename with the mount-wide
 502  * filename encryption key (FNEK) and stores it in a packet to @dest,
 503  * which the callee will encode and write directly into the dentry
 504  * name.
 505  */
 506 int
 507 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
 508                              size_t *packet_size,
 509                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 510                              char *filename, size_t filename_size)
 511 {
 512         struct ecryptfs_write_tag_70_packet_silly_stack *s;
 513         struct key *auth_tok_key = NULL;
 514         int rc = 0;
 515
 516         s = kmalloc(sizeof(*s), GFP_KERNEL);
 517         if (!s) {
 518                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 519                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 520                 rc = -ENOMEM;
 521                 goto out;
 522         }
 523         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 524         (*packet_size) = 0;
 525         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
 526                 &s->desc.tfm,
 527                 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
 528         if (unlikely(rc)) {
 529                 printk(KERN_ERR "Internal error whilst attempting to get "
 530                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
 531                        mount_crypt_stat->global_default_fn_cipher_name, rc);
 532                 goto out;
 533         }
 534         mutex_lock(s->tfm_mutex);
 535         s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
 536         /* Plus one for the \0 separator between the random prefix
 537          * and the plaintext filename */
 538         s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
 539         s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
 540         if ((s->block_aligned_filename_size % s->block_size) != 0) {
 541                 s->num_rand_bytes += (s->block_size
 542                                       - (s->block_aligned_filename_size
 543                                          % s->block_size));
 544                 s->block_aligned_filename_size = (s->num_rand_bytes
 545                                                   + filename_size);
 546         }
 547         /* Octet 0: Tag 70 identifier
 548          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 549          *              and block-aligned encrypted filename size)
 550          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 551          * Octet N2-N3: Cipher identifier (1 octet)
 552          * Octets N3-N4: Block-aligned encrypted filename
 553          *  - Consists of a minimum number of random characters, a \0
 554          *    separator, and then the filename */
 555         s->max_packet_size = (1                   /* Tag 70 identifier */
 556                               + 3                 /* Max Tag 70 packet size */
 557                               + ECRYPTFS_SIG_SIZE /* FNEK sig */
 558                               + 1                 /* Cipher identifier */
 559                               + s->block_aligned_filename_size);
 560         if (dest == NULL) {
 561                 (*packet_size) = s->max_packet_size;
 562                 goto out_unlock;
 563         }
 564         if (s->max_packet_size > (*remaining_bytes)) {
 565                 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
 566                        "[%zd] available\n", __func__, s->max_packet_size,
 567                        (*remaining_bytes));
 568                 rc = -EINVAL;
 569                 goto out_unlock;
 570         }
 571         s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
 572                                             GFP_KERNEL);
 573         if (!s->block_aligned_filename) {
 574                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 575                        "kzalloc [%zd] bytes\n", __func__,
 576                        s->block_aligned_filename_size);
 577                 rc = -ENOMEM;
 578                 goto out_unlock;
 579         }
 580         s->i = 0;
 581         dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
 582         rc = ecryptfs_write_packet_length(&dest[s->i],
 583                                           (ECRYPTFS_SIG_SIZE
 584                                            + 1 /* Cipher code */
 585                                            + s->block_aligned_filename_size),
 586                                           &s->packet_size_len);
 587         if (rc) {
 588                 printk(KERN_ERR "%s: Error generating tag 70 packet "
 589                        "header; cannot generate packet length; rc = [%d]\n",
 590                        __func__, rc);
 591                 goto out_free_unlock;
 592         }
 593         s->i += s->packet_size_len;
 594         ecryptfs_from_hex(&dest[s->i],
 595                           mount_crypt_stat->global_default_fnek_sig,
 596                           ECRYPTFS_SIG_SIZE);
 597         s->i += ECRYPTFS_SIG_SIZE;
 598         s->cipher_code = ecryptfs_code_for_cipher_string(
 599                 mount_crypt_stat->global_default_fn_cipher_name,
 600                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 601         if (s->cipher_code == 0) {
 602                 printk(KERN_WARNING "%s: Unable to generate code for "
 603                        "cipher [%s] with key bytes [%zd]\n", __func__,
 604                        mount_crypt_stat->global_default_fn_cipher_name,
 605                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 606                 rc = -EINVAL;
 607                 goto out_free_unlock;
 608         }
 609         dest[s->i++] = s->cipher_code;
 610         rc = ecryptfs_find_auth_tok_for_sig(
 611                 &auth_tok_key,
 612                 &s->auth_tok, mount_crypt_stat,
 613                 mount_crypt_stat->global_default_fnek_sig);
 614         if (rc) {
 615                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 616                        "fnek sig [%s]; rc = [%d]\n", __func__,
 617                        mount_crypt_stat->global_default_fnek_sig, rc);
 618                 goto out_free_unlock;
 619         }
 620         /* TODO: Support other key modules than passphrase for
 621          * filename encryption */
 622         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
 623                 rc = -EOPNOTSUPP;
 624                 printk(KERN_INFO "%s: Filename encryption only supports "
 625                        "password tokens\n", __func__);
 626                 goto out_free_unlock;
 627         }
 628         sg_init_one(
 629                 &s->hash_sg,
 630                 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
 631                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 632         s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 633         s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
 634                                              CRYPTO_ALG_ASYNC);
 635         if (IS_ERR(s->hash_desc.tfm)) {
 636                         rc = PTR_ERR(s->hash_desc.tfm);
 637                         printk(KERN_ERR "%s: Error attempting to "
 638                                "allocate hash crypto context; rc = [%d]\n",
 639                                __func__, rc);
 640                         goto out_free_unlock;
 641         }
 642         rc = crypto_hash_init(&s->hash_desc);
 643         if (rc) {
 644                 printk(KERN_ERR
 645                        "%s: Error initializing crypto hash; rc = [%d]\n",
 646                        __func__, rc);
 647                 goto out_release_free_unlock;
 648         }
 649         rc = crypto_hash_update(
 650                 &s->hash_desc, &s->hash_sg,
 651                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 652         if (rc) {
 653                 printk(KERN_ERR
 654                        "%s: Error updating crypto hash; rc = [%d]\n",
 655                        __func__, rc);
 656                 goto out_release_free_unlock;
 657         }
 658         rc = crypto_hash_final(&s->hash_desc, s->hash);
 659         if (rc) {
 660                 printk(KERN_ERR
 661                        "%s: Error finalizing crypto hash; rc = [%d]\n",
 662                        __func__, rc);
 663                 goto out_release_free_unlock;
 664         }
 665         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
 666                 s->block_aligned_filename[s->j] =
 667                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
 668                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
 669                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
 670                         sg_init_one(&s->hash_sg, (u8 *)s->hash,
 671                                     ECRYPTFS_TAG_70_DIGEST_SIZE);
 672                         rc = crypto_hash_init(&s->hash_desc);
 673                         if (rc) {
 674                                 printk(KERN_ERR
 675                                        "%s: Error initializing crypto hash; "
 676                                        "rc = [%d]\n", __func__, rc);
 677                                 goto out_release_free_unlock;
 678                         }
 679                         rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
 680                                                 ECRYPTFS_TAG_70_DIGEST_SIZE);
 681                         if (rc) {
 682                                 printk(KERN_ERR
 683                                        "%s: Error updating crypto hash; "
 684                                        "rc = [%d]\n", __func__, rc);
 685                                 goto out_release_free_unlock;
 686                         }
 687                         rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
 688                         if (rc) {
 689                                 printk(KERN_ERR
 690                                        "%s: Error finalizing crypto hash; "
 691                                        "rc = [%d]\n", __func__, rc);
 692                                 goto out_release_free_unlock;
 693                         }
 694                         memcpy(s->hash, s->tmp_hash,
 695                                ECRYPTFS_TAG_70_DIGEST_SIZE);
 696                 }
 697                 if (s->block_aligned_filename[s->j] == '\0')
 698                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
 699         }
 700         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
 701                filename_size);
 702         rc = virt_to_scatterlist(s->block_aligned_filename,
 703                                  s->block_aligned_filename_size, &s->src_sg, 1);
 704         if (rc != 1) {
 705                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 706                        "convert filename memory to scatterlist; "
 707                        "expected rc = 1; got rc = [%d]. "
 708                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 709                        s->block_aligned_filename_size);
 710                 goto out_release_free_unlock;
 711         }
 712         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
 713                                  &s->dst_sg, 1);
 714         if (rc != 1) {
 715                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 716                        "convert encrypted filename memory to scatterlist; "
 717                        "expected rc = 1; got rc = [%d]. "
 718                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 719                        s->block_aligned_filename_size);
 720                 goto out_release_free_unlock;
 721         }
 722         /* The characters in the first block effectively do the job
 723          * of the IV here, so we just use 0's for the IV. Note the
 724          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 725          * >= ECRYPTFS_MAX_IV_BYTES. */
 726         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
 727         s->desc.info = s->iv;
 728         rc = crypto_blkcipher_setkey(
 729                 s->desc.tfm,
 730                 s->auth_tok->token.password.session_key_encryption_key,
 731                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 732         if (rc < 0) {
 733                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 734                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 735                        "encryption_key = [0x%p]; mount_crypt_stat->"
 736                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 737                        rc,
 738                        s->auth_tok->token.password.session_key_encryption_key,
 739                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 740                 goto out_release_free_unlock;
 741         }
 742         rc = crypto_blkcipher_encrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
 743                                          s->block_aligned_filename_size);
 744         if (rc) {
 745                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
 746                        "rc = [%d]\n", __func__, rc);
 747                 goto out_release_free_unlock;
 748         }
 749         s->i += s->block_aligned_filename_size;
 750         (*packet_size) = s->i;
 751         (*remaining_bytes) -= (*packet_size);
 752 out_release_free_unlock:
 753         crypto_free_hash(s->hash_desc.tfm);
 754 out_free_unlock:
 755         kzfree(s->block_aligned_filename);
 756 out_unlock:
 757         mutex_unlock(s->tfm_mutex);
 758 out:
 759         if (auth_tok_key)
 760                 key_put(auth_tok_key);
 761         kfree(s);
 762         return rc;
 763 }
 764
 765 struct ecryptfs_parse_tag_70_packet_silly_stack {
 766         u8 cipher_code;
 767         size_t max_packet_size;
 768         size_t packet_size_len;
 769         size_t parsed_tag_70_packet_size;
 770         size_t block_aligned_filename_size;
 771         size_t block_size;
 772         size_t i;
 773         struct mutex *tfm_mutex;
 774         char *decrypted_filename;
 775         struct ecryptfs_auth_tok *auth_tok;
 776         struct scatterlist src_sg;
 777         struct scatterlist dst_sg;
 778         struct blkcipher_desc desc;
 779         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
 780         char iv[ECRYPTFS_MAX_IV_BYTES];
 781         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
 782 };
 783
 784 /**
 785  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
 786  * @filename: This function kmalloc's the memory for the filename
 787  * @filename_size: This function sets this to the amount of memory
 788  *                 kmalloc'd for the filename
 789  * @packet_size: This function sets this to the the number of octets
 790  *               in the packet parsed
 791  * @mount_crypt_stat: The mount-wide cryptographic context
 792  * @data: The memory location containing the start of the tag 70
 793  *        packet
 794  * @max_packet_size: The maximum legal size of the packet to be parsed
 795  *                   from @data
 796  *
 797  * Returns zero on success; non-zero otherwise
 798  */
 799 int
 800 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 801                              size_t *packet_size,
 802                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 803                              char *data, size_t max_packet_size)
 804 {
 805         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
 806         struct key *auth_tok_key = NULL;
 807         int rc = 0;
 808
 809         (*packet_size) = 0;
 810         (*filename_size) = 0;
 811         (*filename) = NULL;
 812         s = kmalloc(sizeof(*s), GFP_KERNEL);
 813         if (!s) {
 814                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 815                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 816                 rc = -ENOMEM;
 817                 goto out;
 818         }
 819         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 820         if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
 821                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
 822                        "at least [%d]\n", __func__, max_packet_size,
 823                         (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
 824                 rc = -EINVAL;
 825                 goto out;
 826         }
 827         /* Octet 0: Tag 70 identifier
 828          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 829          *              and block-aligned encrypted filename size)
 830          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 831          * Octet N2-N3: Cipher identifier (1 octet)
 832          * Octets N3-N4: Block-aligned encrypted filename
 833          *  - Consists of a minimum number of random numbers, a \0
 834          *    separator, and then the filename */
 835         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
 836                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
 837                        "tag [0x%.2x]\n", __func__,
 838                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
 839                 rc = -EINVAL;
 840                 goto out;
 841         }
 842         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
 843                                           &s->parsed_tag_70_packet_size,
 844                                           &s->packet_size_len);
 845         if (rc) {
 846                 printk(KERN_WARNING "%s: Error parsing packet length; "
 847                        "rc = [%d]\n", __func__, rc);
 848                 goto out;
 849         }
 850         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
 851                                           - ECRYPTFS_SIG_SIZE - 1);
 852         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
 853             > max_packet_size) {
 854                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
 855                        "size is [%zd]\n", __func__, max_packet_size,
 856                        (1 + s->packet_size_len + 1
 857                         + s->block_aligned_filename_size));
 858                 rc = -EINVAL;
 859                 goto out;
 860         }
 861         (*packet_size) += s->packet_size_len;
 862         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
 863                         ECRYPTFS_SIG_SIZE);
 864         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 865         (*packet_size) += ECRYPTFS_SIG_SIZE;
 866         s->cipher_code = data[(*packet_size)++];
 867         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
 868         if (rc) {
 869                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
 870                        __func__, s->cipher_code);
 871                 goto out;
 872         }
 873         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
 874                                                         &s->tfm_mutex,
 875                                                         s->cipher_string);
 876         if (unlikely(rc)) {
 877                 printk(KERN_ERR "Internal error whilst attempting to get "
 878                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
 879                        s->cipher_string, rc);
 880                 goto out;
 881         }
 882         mutex_lock(s->tfm_mutex);
 883         rc = virt_to_scatterlist(&data[(*packet_size)],
 884                                  s->block_aligned_filename_size, &s->src_sg, 1);
 885         if (rc != 1) {
 886                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 887                        "convert encrypted filename memory to scatterlist; "
 888                        "expected rc = 1; got rc = [%d]. "
 889                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 890                        s->block_aligned_filename_size);
 891                 goto out_unlock;
 892         }
 893         (*packet_size) += s->block_aligned_filename_size;
 894         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
 895                                         GFP_KERNEL);
 896         if (!s->decrypted_filename) {
 897                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
 898                        "kmalloc [%zd] bytes\n", __func__,
 899                        s->block_aligned_filename_size);
 900                 rc = -ENOMEM;
 901                 goto out_unlock;
 902         }
 903         rc = virt_to_scatterlist(s->decrypted_filename,
 904                                  s->block_aligned_filename_size, &s->dst_sg, 1);
 905         if (rc != 1) {
 906                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 907                        "convert decrypted filename memory to scatterlist; "
 908                        "expected rc = 1; got rc = [%d]. "
 909                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 910                        s->block_aligned_filename_size);
 911                 goto out_free_unlock;
 912         }
 913         /* The characters in the first block effectively do the job of
 914          * the IV here, so we just use 0's for the IV. Note the
 915          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 916          * >= ECRYPTFS_MAX_IV_BYTES. */
 917         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
 918         s->desc.info = s->iv;
 919         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
 920                                             &s->auth_tok, mount_crypt_stat,
 921                                             s->fnek_sig_hex);
 922         if (rc) {
 923                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 924                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
 925                        rc);
 926                 goto out_free_unlock;
 927         }
 928         /* TODO: Support other key modules than passphrase for
 929          * filename encryption */
 930         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
 931                 rc = -EOPNOTSUPP;
 932                 printk(KERN_INFO "%s: Filename encryption only supports "
 933                        "password tokens\n", __func__);
 934                 goto out_free_unlock;
 935         }
 936         rc = crypto_blkcipher_setkey(
 937                 s->desc.tfm,
 938                 s->auth_tok->token.password.session_key_encryption_key,
 939                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 940         if (rc < 0) {
 941                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 942                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 943                        "encryption_key = [0x%p]; mount_crypt_stat->"
 944                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 945                        rc,
 946                        s->auth_tok->token.password.session_key_encryption_key,
 947                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 948                 goto out_free_unlock;
 949         }
 950         rc = crypto_blkcipher_decrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
 951                                          s->block_aligned_filename_size);
 952         if (rc) {
 953                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
 954                        "rc = [%d]\n", __func__, rc);
 955                 goto out_free_unlock;
 956         }
 957         s->i = 0;
 958         while (s->decrypted_filename[s->i] != '\0'
 959                && s->i < s->block_aligned_filename_size)
 960                 s->i++;
 961         if (s->i == s->block_aligned_filename_size) {
 962                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
 963                        "find valid separator between random characters and "
 964                        "the filename\n", __func__);
 965                 rc = -EINVAL;
 966                 goto out_free_unlock;
 967         }
 968         s->i++;
 969         (*filename_size) = (s->block_aligned_filename_size - s->i);
 970         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
 971                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
 972                        "invalid\n", __func__, (*filename_size));
 973                 rc = -EINVAL;
 974                 goto out_free_unlock;
 975         }
 976         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
 977         if (!(*filename)) {
 978                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
 979                        "kmalloc [%zd] bytes\n", __func__,
 980                        ((*filename_size) + 1));
 981                 rc = -ENOMEM;
 982                 goto out_free_unlock;
 983         }
 984         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
 985         (*filename)[(*filename_size)] = '\0';
 986 out_free_unlock:
 987         kfree(s->decrypted_filename);
 988 out_unlock:
 989         mutex_unlock(s->tfm_mutex);
 990 out:
 991         if (rc) {
 992                 (*packet_size) = 0;
 993                 (*filename_size) = 0;
 994                 (*filename) = NULL;
 995         }
 996         if (auth_tok_key)
 997                 key_put(auth_tok_key);
 998         kfree(s);
 999         return rc;
1000 }
1001
1002 static int
1003 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1004 {
1005         int rc = 0;
1006
1007         (*sig) = NULL;
1008         switch (auth_tok->token_type) {
1009         case ECRYPTFS_PASSWORD:
1010                 (*sig) = auth_tok->token.password.signature;
1011                 break;
1012         case ECRYPTFS_PRIVATE_KEY:
1013                 (*sig) = auth_tok->token.private_key.signature;
1014                 break;
1015         default:
1016                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1017                        auth_tok->token_type);
1018                 rc = -EINVAL;
1019         }
1020         return rc;
1021 }
1022
1023 /**
1024  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1025  * @auth_tok: The key authentication token used to decrypt the session key
1026  * @crypt_stat: The cryptographic context
1027  *
1028  * Returns zero on success; non-zero error otherwise.
1029  */
1030 static int
1031 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1032                                   struct ecryptfs_crypt_stat *crypt_stat)
1033 {
1034         u8 cipher_code = 0;
1035         struct ecryptfs_msg_ctx *msg_ctx;
1036         struct ecryptfs_message *msg = NULL;
1037         char *auth_tok_sig;
1038         char *payload;
1039         size_t payload_len;
1040         int rc;
1041
1042         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1043         if (rc) {
1044                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1045                        auth_tok->token_type);
1046                 goto out;
1047         }
1048         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1049                                  &payload, &payload_len);
1050         if (rc) {
1051                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1052                 goto out;
1053         }
1054         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1055         if (rc) {
1056                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1057                                 "ecryptfsd\n");
1058                 goto out;
1059         }
1060         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1061         if (rc) {
1062                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1063                                 "from the user space daemon\n");
1064                 rc = -EIO;
1065                 goto out;
1066         }
1067         rc = parse_tag_65_packet(&(auth_tok->session_key),
1068                                  &cipher_code, msg);
1069         if (rc) {
1070                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1071                        rc);
1072                 goto out;
1073         }
1074         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1075         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1076                auth_tok->session_key.decrypted_key_size);
1077         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1078         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1079         if (rc) {
1080                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1081                                 cipher_code)
1082                 goto out;
1083         }
1084         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1085         if (ecryptfs_verbosity > 0) {
1086                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1087                 ecryptfs_dump_hex(crypt_stat->key,
1088                                   crypt_stat->key_size);
1089         }
1090 out:
1091         if (msg)
1092                 kfree(msg);
1093         return rc;
1094 }
1095
1096 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1097 {
1098         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1099         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1100
1101         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1102                                  auth_tok_list_head, list) {
1103                 list_del(&auth_tok_list_item->list);
1104                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1105                                 auth_tok_list_item);
1106         }
1107 }
1108
1109 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1110
1111 /**
1112  * parse_tag_1_packet
1113  * @crypt_stat: The cryptographic context to modify based on packet contents
1114  * @data: The raw bytes of the packet.
1115  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1116  *                 a new authentication token will be placed at the
1117  *                 end of this list for this packet.
1118  * @new_auth_tok: Pointer to a pointer to memory that this function
1119  *                allocates; sets the memory address of the pointer to
1120  *                NULL on error. This object is added to the
1121  *                auth_tok_list.
1122  * @packet_size: This function writes the size of the parsed packet
1123  *               into this memory location; zero on error.
1124  * @max_packet_size: The maximum allowable packet size
1125  *
1126  * Returns zero on success; non-zero on error.
1127  */
1128 static int
1129 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1130                    unsigned char *data, struct list_head *auth_tok_list,
1131                    struct ecryptfs_auth_tok **new_auth_tok,
1132                    size_t *packet_size, size_t max_packet_size)
1133 {
1134         size_t body_size;
1135         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1136         size_t length_size;
1137         int rc = 0;
1138
1139         (*packet_size) = 0;
1140         (*new_auth_tok) = NULL;
1141         /**
1142          * This format is inspired by OpenPGP; see RFC 2440
1143          * packet tag 1
1144          *
1145          * Tag 1 identifier (1 byte)
1146          * Max Tag 1 packet size (max 3 bytes)
1147          * Version (1 byte)
1148          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1149          * Cipher identifier (1 byte)
1150          * Encrypted key size (arbitrary)
1151          *
1152          * 12 bytes minimum packet size
1153          */
1154         if (unlikely(max_packet_size < 12)) {
1155                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1156                 rc = -EINVAL;
1157                 goto out;
1158         }
1159         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1160                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1161                        ECRYPTFS_TAG_1_PACKET_TYPE);
1162                 rc = -EINVAL;
1163                 goto out;
1164         }
1165         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1166          * at end of function upon failure */
1167         auth_tok_list_item =
1168                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1169                                   GFP_KERNEL);
1170         if (!auth_tok_list_item) {
1171                 printk(KERN_ERR "Unable to allocate memory\n");
1172                 rc = -ENOMEM;
1173                 goto out;
1174         }
1175         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1176         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1177                                           &length_size);
1178         if (rc) {
1179                 printk(KERN_WARNING "Error parsing packet length; "
1180                        "rc = [%d]\n", rc);
1181                 goto out_free;
1182         }
1183         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1184                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1185                 rc = -EINVAL;
1186                 goto out_free;
1187         }
1188         (*packet_size) += length_size;
1189         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1190                 printk(KERN_WARNING "Packet size exceeds max\n");
1191                 rc = -EINVAL;
1192                 goto out_free;
1193         }
1194         if (unlikely(data[(*packet_size)++] != 0x03)) {
1195                 printk(KERN_WARNING "Unknown version number [%d]\n",
1196                        data[(*packet_size) - 1]);
1197                 rc = -EINVAL;
1198                 goto out_free;
1199         }
1200         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1201                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1202         *packet_size += ECRYPTFS_SIG_SIZE;
1203         /* This byte is skipped because the kernel does not need to
1204          * know which public key encryption algorithm was used */
1205         (*packet_size)++;
1206         (*new_auth_tok)->session_key.encrypted_key_size =
1207                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1208         if ((*new_auth_tok)->session_key.encrypted_key_size
1209             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1210                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1211                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1212                 rc = -EINVAL;
1213                 goto out;
1214         }
1215         memcpy((*new_auth_tok)->session_key.encrypted_key,
1216                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1217         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1218         (*new_auth_tok)->session_key.flags &=
1219                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1220         (*new_auth_tok)->session_key.flags |=
1221                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1222         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1223         (*new_auth_tok)->flags = 0;
1224         (*new_auth_tok)->session_key.flags &=
1225                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1226         (*new_auth_tok)->session_key.flags &=
1227                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1228         list_add(&auth_tok_list_item->list, auth_tok_list);
1229         goto out;
1230 out_free:
1231         (*new_auth_tok) = NULL;
1232         memset(auth_tok_list_item, 0,
1233                sizeof(struct ecryptfs_auth_tok_list_item));
1234         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1235                         auth_tok_list_item);
1236 out:
1237         if (rc)
1238                 (*packet_size) = 0;
1239         return rc;
1240 }
1241
1242 /**
1243  * parse_tag_3_packet
1244  * @crypt_stat: The cryptographic context to modify based on packet
1245  *              contents.
1246  * @data: The raw bytes of the packet.
1247  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1248  *                 a new authentication token will be placed at the end
1249  *                 of this list for this packet.
1250  * @new_auth_tok: Pointer to a pointer to memory that this function
1251  *                allocates; sets the memory address of the pointer to
1252  *                NULL on error. This object is added to the
1253  *                auth_tok_list.
1254  * @packet_size: This function writes the size of the parsed packet
1255  *               into this memory location; zero on error.
1256  * @max_packet_size: maximum number of bytes to parse
1257  *
1258  * Returns zero on success; non-zero on error.
1259  */
1260 static int
1261 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1262                    unsigned char *data, struct list_head *auth_tok_list,
1263                    struct ecryptfs_auth_tok **new_auth_tok,
1264                    size_t *packet_size, size_t max_packet_size)
1265 {
1266         size_t body_size;
1267         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1268         size_t length_size;
1269         int rc = 0;
1270
1271         (*packet_size) = 0;
1272         (*new_auth_tok) = NULL;
1273         /**
1274          *This format is inspired by OpenPGP; see RFC 2440
1275          * packet tag 3
1276          *
1277          * Tag 3 identifier (1 byte)
1278          * Max Tag 3 packet size (max 3 bytes)
1279          * Version (1 byte)
1280          * Cipher code (1 byte)
1281          * S2K specifier (1 byte)
1282          * Hash identifier (1 byte)
1283          * Salt (ECRYPTFS_SALT_SIZE)
1284          * Hash iterations (1 byte)
1285          * Encrypted key (arbitrary)
1286          *
1287          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1288          */
1289         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1290                 printk(KERN_ERR "Max packet size too large\n");
1291                 rc = -EINVAL;
1292                 goto out;
1293         }
1294         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1295                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1296                        ECRYPTFS_TAG_3_PACKET_TYPE);
1297                 rc = -EINVAL;
1298                 goto out;
1299         }
1300         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1301          * at end of function upon failure */
1302         auth_tok_list_item =
1303             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1304         if (!auth_tok_list_item) {
1305                 printk(KERN_ERR "Unable to allocate memory\n");
1306                 rc = -ENOMEM;
1307                 goto out;
1308         }
1309         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1310         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1311                                           &length_size);
1312         if (rc) {
1313                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1314                        rc);
1315                 goto out_free;
1316         }
1317         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1318                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1319                 rc = -EINVAL;
1320                 goto out_free;
1321         }
1322         (*packet_size) += length_size;
1323         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1324                 printk(KERN_ERR "Packet size exceeds max\n");
1325                 rc = -EINVAL;
1326                 goto out_free;
1327         }
1328         (*new_auth_tok)->session_key.encrypted_key_size =
1329                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1330         if ((*new_auth_tok)->session_key.encrypted_key_size
1331             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1332                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1333                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1334                 rc = -EINVAL;
1335                 goto out_free;
1336         }
1337         if (unlikely(data[(*packet_size)++] != 0x04)) {
1338                 printk(KERN_WARNING "Unknown version number [%d]\n",
1339                        data[(*packet_size) - 1]);
1340                 rc = -EINVAL;
1341                 goto out_free;
1342         }
1343         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1344                                             (u16)data[(*packet_size)]);
1345         if (rc)
1346                 goto out_free;
1347         /* A little extra work to differentiate among the AES key
1348          * sizes; see RFC2440 */
1349         switch(data[(*packet_size)++]) {
1350         case RFC2440_CIPHER_AES_192:
1351                 crypt_stat->key_size = 24;
1352                 break;
1353         default:
1354                 crypt_stat->key_size =
1355                         (*new_auth_tok)->session_key.encrypted_key_size;
1356         }
1357         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1358         if (rc)
1359                 goto out_free;
1360         if (unlikely(data[(*packet_size)++] != 0x03)) {
1361                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1362                 rc = -ENOSYS;
1363                 goto out_free;
1364         }
1365         /* TODO: finish the hash mapping */
1366         switch (data[(*packet_size)++]) {
1367         case 0x01: /* See RFC2440 for these numbers and their mappings */
1368                 /* Choose MD5 */
1369                 memcpy((*new_auth_tok)->token.password.salt,
1370                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1371                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1372                 /* This conversion was taken straight from RFC2440 */
1373                 (*new_auth_tok)->token.password.hash_iterations =
1374                         ((u32) 16 + (data[(*packet_size)] & 15))
1375                                 << ((data[(*packet_size)] >> 4) + 6);
1376                 (*packet_size)++;
1377                 /* Friendly reminder:
1378                  * (*new_auth_tok)->session_key.encrypted_key_size =
1379                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1380                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1381                        &data[(*packet_size)],
1382                        (*new_auth_tok)->session_key.encrypted_key_size);
1383                 (*packet_size) +=
1384                         (*new_auth_tok)->session_key.encrypted_key_size;
1385                 (*new_auth_tok)->session_key.flags &=
1386                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1387                 (*new_auth_tok)->session_key.flags |=
1388                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1389                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1390                 break;
1391         default:
1392                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1393                                 "[%d]\n", data[(*packet_size) - 1]);
1394                 rc = -ENOSYS;
1395                 goto out_free;
1396         }
1397         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1398         /* TODO: Parametarize; we might actually want userspace to
1399          * decrypt the session key. */
1400         (*new_auth_tok)->session_key.flags &=
1401                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1402         (*new_auth_tok)->session_key.flags &=
1403                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1404         list_add(&auth_tok_list_item->list, auth_tok_list);
1405         goto out;
1406 out_free:
1407         (*new_auth_tok) = NULL;
1408         memset(auth_tok_list_item, 0,
1409                sizeof(struct ecryptfs_auth_tok_list_item));
1410         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1411                         auth_tok_list_item);
1412 out:
1413         if (rc)
1414                 (*packet_size) = 0;
1415         return rc;
1416 }
1417
1418 /**
1419  * parse_tag_11_packet
1420  * @data: The raw bytes of the packet
1421  * @contents: This function writes the data contents of the literal
1422  *            packet into this memory location
1423  * @max_contents_bytes: The maximum number of bytes that this function
1424  *                      is allowed to write into contents
1425  * @tag_11_contents_size: This function writes the size of the parsed
1426  *                        contents into this memory location; zero on
1427  *                        error
1428  * @packet_size: This function writes the size of the parsed packet
1429  *               into this memory location; zero on error
1430  * @max_packet_size: maximum number of bytes to parse
1431  *
1432  * Returns zero on success; non-zero on error.
1433  */
1434 static int
1435 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1436                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1437                     size_t *packet_size, size_t max_packet_size)
1438 {
1439         size_t body_size;
1440         size_t length_size;
1441         int rc = 0;
1442
1443         (*packet_size) = 0;
1444         (*tag_11_contents_size) = 0;
1445         /* This format is inspired by OpenPGP; see RFC 2440
1446          * packet tag 11
1447          *
1448          * Tag 11 identifier (1 byte)
1449          * Max Tag 11 packet size (max 3 bytes)
1450          * Binary format specifier (1 byte)
1451          * Filename length (1 byte)
1452          * Filename ("_CONSOLE") (8 bytes)
1453          * Modification date (4 bytes)
1454          * Literal data (arbitrary)
1455          *
1456          * We need at least 16 bytes of data for the packet to even be
1457          * valid.
1458          */
1459         if (max_packet_size < 16) {
1460                 printk(KERN_ERR "Maximum packet size too small\n");
1461                 rc = -EINVAL;
1462                 goto out;
1463         }
1464         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1465                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1466                 rc = -EINVAL;
1467                 goto out;
1468         }
1469         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1470                                           &length_size);
1471         if (rc) {
1472                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1473                 goto out;
1474         }
1475         if (body_size < 14) {
1476                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1477                 rc = -EINVAL;
1478                 goto out;
1479         }
1480         (*packet_size) += length_size;
1481         (*tag_11_contents_size) = (body_size - 14);
1482         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1483                 printk(KERN_ERR "Packet size exceeds max\n");
1484                 rc = -EINVAL;
1485                 goto out;
1486         }
1487         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1488                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1489                        "expected size\n");
1490                 rc = -EINVAL;
1491                 goto out;
1492         }
1493         if (data[(*packet_size)++] != 0x62) {
1494                 printk(KERN_WARNING "Unrecognizable packet\n");
1495                 rc = -EINVAL;
1496                 goto out;
1497         }
1498         if (data[(*packet_size)++] != 0x08) {
1499                 printk(KERN_WARNING "Unrecognizable packet\n");
1500                 rc = -EINVAL;
1501                 goto out;
1502         }
1503         (*packet_size) += 12; /* Ignore filename and modification date */
1504         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1505         (*packet_size) += (*tag_11_contents_size);
1506 out:
1507         if (rc) {
1508                 (*packet_size) = 0;
1509                 (*tag_11_contents_size) = 0;
1510         }
1511         return rc;
1512 }
1513
1514 /**
1515  * ecryptfs_verify_version
1516  * @version: The version number to confirm
1517  *
1518  * Returns zero on good version; non-zero otherwise
1519  */
1520 static int ecryptfs_verify_version(u16 version)
1521 {
1522         int rc = 0;
1523         unsigned char major;
1524         unsigned char minor;
1525
1526         major = ((version >> 8) & 0xFF);
1527         minor = (version & 0xFF);
1528         if (major != ECRYPTFS_VERSION_MAJOR) {
1529                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
1530                                 "Expected [%d]; got [%d]\n",
1531                                 ECRYPTFS_VERSION_MAJOR, major);
1532                 rc = -EINVAL;
1533                 goto out;
1534         }
1535         if (minor != ECRYPTFS_VERSION_MINOR) {
1536                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
1537                                 "Expected [%d]; got [%d]\n",
1538                                 ECRYPTFS_VERSION_MINOR, minor);
1539                 rc = -EINVAL;
1540                 goto out;
1541         }
1542 out:
1543         return rc;
1544 }
1545
1546 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1547                                       struct ecryptfs_auth_tok **auth_tok,
1548                                       char *sig)
1549 {
1550         int rc = 0;
1551
1552         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1553         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1554                 printk(KERN_ERR "Could not find key with description: [%s]\n",
1555                        sig);
1556                 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1557                 goto out;
1558         }
1559         (*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
1560         if (ecryptfs_verify_version((*auth_tok)->version)) {
1561                 printk(KERN_ERR
1562                        "Data structure version mismatch. "
1563                        "Userspace tools must match eCryptfs "
1564                        "kernel module with major version [%d] "
1565                        "and minor version [%d]\n",
1566                        ECRYPTFS_VERSION_MAJOR,
1567                        ECRYPTFS_VERSION_MINOR);
1568                 rc = -EINVAL;
1569                 goto out_release_key;
1570         }
1571         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
1572             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
1573                 printk(KERN_ERR "Invalid auth_tok structure "
1574                        "returned from key query\n");
1575                 rc = -EINVAL;
1576                 goto out_release_key;
1577         }
1578 out_release_key:
1579         if (rc) {
1580                 key_put(*auth_tok_key);
1581                 (*auth_tok_key) = NULL;
1582         }
1583 out:
1584         return rc;
1585 }
1586
1587 /**
1588  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1589  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1590  * @crypt_stat: The cryptographic context
1591  *
1592  * Returns zero on success; non-zero error otherwise
1593  */
1594 static int
1595 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1596                                          struct ecryptfs_crypt_stat *crypt_stat)
1597 {
1598         struct scatterlist dst_sg[2];
1599         struct scatterlist src_sg[2];
1600         struct mutex *tfm_mutex;
1601         struct blkcipher_desc desc = {
1602                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1603         };
1604         int rc = 0;
1605
1606         if (unlikely(ecryptfs_verbosity > 0)) {
1607                 ecryptfs_printk(
1608                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1609                         auth_tok->token.password.session_key_encryption_key_bytes);
1610                 ecryptfs_dump_hex(
1611                         auth_tok->token.password.session_key_encryption_key,
1612                         auth_tok->token.password.session_key_encryption_key_bytes);
1613         }
1614         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1615                                                         crypt_stat->cipher);
1616         if (unlikely(rc)) {
1617                 printk(KERN_ERR "Internal error whilst attempting to get "
1618                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1619                        crypt_stat->cipher, rc);
1620                 goto out;
1621         }
1622         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1623                                  auth_tok->session_key.encrypted_key_size,
1624                                  src_sg, 2);
1625         if (rc < 1 || rc > 2) {
1626                 printk(KERN_ERR "Internal error whilst attempting to convert "
1627                         "auth_tok->session_key.encrypted_key to scatterlist; "
1628                         "expected rc = 1; got rc = [%d]. "
1629                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1630                         auth_tok->session_key.encrypted_key_size);
1631                 goto out;
1632         }
1633         auth_tok->session_key.decrypted_key_size =
1634                 auth_tok->session_key.encrypted_key_size;
1635         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1636                                  auth_tok->session_key.decrypted_key_size,
1637                                  dst_sg, 2);
1638         if (rc < 1 || rc > 2) {
1639                 printk(KERN_ERR "Internal error whilst attempting to convert "
1640                         "auth_tok->session_key.decrypted_key to scatterlist; "
1641                         "expected rc = 1; got rc = [%d]\n", rc);
1642                 goto out;
1643         }
1644         mutex_lock(tfm_mutex);
1645         rc = crypto_blkcipher_setkey(
1646                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1647                 crypt_stat->key_size);
1648         if (unlikely(rc < 0)) {
1649                 mutex_unlock(tfm_mutex);
1650                 printk(KERN_ERR "Error setting key for crypto context\n");
1651                 rc = -EINVAL;
1652                 goto out;
1653         }
1654         rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1655                                       auth_tok->session_key.encrypted_key_size);
1656         mutex_unlock(tfm_mutex);
1657         if (unlikely(rc)) {
1658                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1659                 goto out;
1660         }
1661         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1662         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1663                auth_tok->session_key.decrypted_key_size);
1664         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1665         if (unlikely(ecryptfs_verbosity > 0)) {
1666                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
1667                                 crypt_stat->key_size);
1668                 ecryptfs_dump_hex(crypt_stat->key,
1669                                   crypt_stat->key_size);
1670         }
1671 out:
1672         return rc;
1673 }
1674
1675 /**
1676  * ecryptfs_parse_packet_set
1677  * @crypt_stat: The cryptographic context
1678  * @src: Virtual address of region of memory containing the packets
1679  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1680  *
1681  * Get crypt_stat to have the file's session key if the requisite key
1682  * is available to decrypt the session key.
1683  *
1684  * Returns Zero if a valid authentication token was retrieved and
1685  * processed; negative value for file not encrypted or for error
1686  * conditions.
1687  */
1688 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1689                               unsigned char *src,
1690                               struct dentry *ecryptfs_dentry)
1691 {
1692         size_t i = 0;
1693         size_t found_auth_tok;
1694         size_t next_packet_is_auth_tok_packet;
1695         struct list_head auth_tok_list;
1696         struct ecryptfs_auth_tok *matching_auth_tok;
1697         struct ecryptfs_auth_tok *candidate_auth_tok;
1698         char *candidate_auth_tok_sig;
1699         size_t packet_size;
1700         struct ecryptfs_auth_tok *new_auth_tok;
1701         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1702         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1703         size_t tag_11_contents_size;
1704         size_t tag_11_packet_size;
1705         struct key *auth_tok_key = NULL;
1706         int rc = 0;
1707
1708         INIT_LIST_HEAD(&auth_tok_list);
1709         /* Parse the header to find as many packets as we can; these will be
1710          * added the our &auth_tok_list */
1711         next_packet_is_auth_tok_packet = 1;
1712         while (next_packet_is_auth_tok_packet) {
1713                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1714
1715                 switch (src[i]) {
1716                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1717                         rc = parse_tag_3_packet(crypt_stat,
1718                                                 (unsigned char *)&src[i],
1719                                                 &auth_tok_list, &new_auth_tok,
1720                                                 &packet_size, max_packet_size);
1721                         if (rc) {
1722                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1723                                                 "tag 3 packet\n");
1724                                 rc = -EIO;
1725                                 goto out_wipe_list;
1726                         }
1727                         i += packet_size;
1728                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1729                                                  sig_tmp_space,
1730                                                  ECRYPTFS_SIG_SIZE,
1731                                                  &tag_11_contents_size,
1732                                                  &tag_11_packet_size,
1733                                                  max_packet_size);
1734                         if (rc) {
1735                                 ecryptfs_printk(KERN_ERR, "No valid "
1736                                                 "(ecryptfs-specific) literal "
1737                                                 "packet containing "
1738                                                 "authentication token "
1739                                                 "signature found after "
1740                                                 "tag 3 packet\n");
1741                                 rc = -EIO;
1742                                 goto out_wipe_list;
1743                         }
1744                         i += tag_11_packet_size;
1745                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1746                                 ecryptfs_printk(KERN_ERR, "Expected "
1747                                                 "signature of size [%d]; "
1748                                                 "read size [%d]\n",
1749                                                 ECRYPTFS_SIG_SIZE,
1750                                                 tag_11_contents_size);
1751                                 rc = -EIO;
1752                                 goto out_wipe_list;
1753                         }
1754                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1755                                         sig_tmp_space, tag_11_contents_size);
1756                         new_auth_tok->token.password.signature[
1757                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1758                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1759                         break;
1760                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1761                         rc = parse_tag_1_packet(crypt_stat,
1762                                                 (unsigned char *)&src[i],
1763                                                 &auth_tok_list, &new_auth_tok,
1764                                                 &packet_size, max_packet_size);
1765                         if (rc) {
1766                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1767                                                 "tag 1 packet\n");
1768                                 rc = -EIO;
1769                                 goto out_wipe_list;
1770                         }
1771                         i += packet_size;
1772                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1773                         break;
1774                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1775                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1776                                         "(Tag 11 not allowed by itself)\n");
1777                         rc = -EIO;
1778                         goto out_wipe_list;
1779                         break;
1780                 default:
1781                         ecryptfs_printk(KERN_DEBUG, "No packet at offset "
1782                                         "[%d] of the file header; hex value of "
1783                                         "character is [0x%.2x]\n", i, src[i]);
1784                         next_packet_is_auth_tok_packet = 0;
1785                 }
1786         }
1787         if (list_empty(&auth_tok_list)) {
1788                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1789                        "eCryptfs file; this is not supported in this version "
1790                        "of the eCryptfs kernel module\n");
1791                 rc = -EINVAL;
1792                 goto out;
1793         }
1794         /* auth_tok_list contains the set of authentication tokens
1795          * parsed from the metadata. We need to find a matching
1796          * authentication token that has the secret component(s)
1797          * necessary to decrypt the EFEK in the auth_tok parsed from
1798          * the metadata. There may be several potential matches, but
1799          * just one will be sufficient to decrypt to get the FEK. */
1800 find_next_matching_auth_tok:
1801         found_auth_tok = 0;
1802         if (auth_tok_key) {
1803                 key_put(auth_tok_key);
1804                 auth_tok_key = NULL;
1805         }
1806         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1807                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1808                 if (unlikely(ecryptfs_verbosity > 0)) {
1809                         ecryptfs_printk(KERN_DEBUG,
1810                                         "Considering cadidate auth tok:\n");
1811                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1812                 }
1813                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1814                                                candidate_auth_tok);
1815                 if (rc) {
1816                         printk(KERN_ERR
1817                                "Unrecognized candidate auth tok type: [%d]\n",
1818                                candidate_auth_tok->token_type);
1819                         rc = -EINVAL;
1820                         goto out_wipe_list;
1821                 }
1822                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1823                                                &matching_auth_tok,
1824                                                crypt_stat->mount_crypt_stat,
1825                                                candidate_auth_tok_sig);
1826                 if (!rc) {
1827                         found_auth_tok = 1;
1828                         goto found_matching_auth_tok;
1829                 }
1830         }
1831         if (!found_auth_tok) {
1832                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1833                                 "authentication token\n");
1834                 rc = -EIO;
1835                 goto out_wipe_list;
1836         }
1837 found_matching_auth_tok:
1838         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1839                 memcpy(&(candidate_auth_tok->token.private_key),
1840                        &(matching_auth_tok->token.private_key),
1841                        sizeof(struct ecryptfs_private_key));
1842                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1843                                                        crypt_stat);
1844         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1845                 memcpy(&(candidate_auth_tok->token.password),
1846                        &(matching_auth_tok->token.password),
1847                        sizeof(struct ecryptfs_password));
1848                 rc = decrypt_passphrase_encrypted_session_key(
1849                         candidate_auth_tok, crypt_stat);
1850         }
1851         if (rc) {
1852                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1853
1854                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1855                                 "session key for authentication token with sig "
1856                                 "[%.*s]; rc = [%d]. Removing auth tok "
1857                                 "candidate from the list and searching for "
1858                                 "the next match.\n", candidate_auth_tok_sig,
1859                                 ECRYPTFS_SIG_SIZE_HEX, rc);
1860                 list_for_each_entry_safe(auth_tok_list_item,
1861                                          auth_tok_list_item_tmp,
1862                                          &auth_tok_list, list) {
1863                         if (candidate_auth_tok
1864                             == &auth_tok_list_item->auth_tok) {
1865                                 list_del(&auth_tok_list_item->list);
1866                                 kmem_cache_free(
1867                                         ecryptfs_auth_tok_list_item_cache,
1868                                         auth_tok_list_item);
1869                                 goto find_next_matching_auth_tok;
1870                         }
1871                 }
1872                 BUG();
1873         }
1874         rc = ecryptfs_compute_root_iv(crypt_stat);
1875         if (rc) {
1876                 ecryptfs_printk(KERN_ERR, "Error computing "
1877                                 "the root IV\n");
1878                 goto out_wipe_list;
1879         }
1880         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1881         if (rc) {
1882                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1883                                 "context for cipher [%s]; rc = [%d]\n",
1884                                 crypt_stat->cipher, rc);
1885         }
1886 out_wipe_list:
1887         wipe_auth_tok_list(&auth_tok_list);
1888 out:
1889         if (auth_tok_key)
1890                 key_put(auth_tok_key);
1891         return rc;
1892 }
1893
1894 static int
1895 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1896                         struct ecryptfs_crypt_stat *crypt_stat,
1897                         struct ecryptfs_key_record *key_rec)
1898 {
1899         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1900         char *payload = NULL;
1901         size_t payload_len;
1902         struct ecryptfs_message *msg;
1903         int rc;
1904
1905         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1906                                  ecryptfs_code_for_cipher_string(
1907                                          crypt_stat->cipher,
1908                                          crypt_stat->key_size),
1909                                  crypt_stat, &payload, &payload_len);
1910         if (rc) {
1911                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1912                 goto out;
1913         }
1914         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1915         if (rc) {
1916                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1917                                 "ecryptfsd\n");
1918                 goto out;
1919         }
1920         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1921         if (rc) {
1922                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1923                                 "from the user space daemon\n");
1924                 rc = -EIO;
1925                 goto out;
1926         }
1927         rc = parse_tag_67_packet(key_rec, msg);
1928         if (rc)
1929                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1930         kfree(msg);
1931 out:
1932         kfree(payload);
1933         return rc;
1934 }
1935 /**
1936  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1937  * @dest: Buffer into which to write the packet
1938  * @remaining_bytes: Maximum number of bytes that can be writtn
1939  * @auth_tok: The authentication token used for generating the tag 1 packet
1940  * @crypt_stat: The cryptographic context
1941  * @key_rec: The key record struct for the tag 1 packet
1942  * @packet_size: This function will write the number of bytes that end
1943  *               up constituting the packet; set to zero on error
1944  *
1945  * Returns zero on success; non-zero on error.
1946  */
1947 static int
1948 write_tag_1_packet(char *dest, size_t *remaining_bytes,
1949                    struct ecryptfs_auth_tok *auth_tok,
1950                    struct ecryptfs_crypt_stat *crypt_stat,
1951                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1952 {
1953         size_t i;
1954         size_t encrypted_session_key_valid = 0;
1955         size_t packet_size_length;
1956         size_t max_packet_size;
1957         int rc = 0;
1958
1959         (*packet_size) = 0;
1960         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
1961                           ECRYPTFS_SIG_SIZE);
1962         encrypted_session_key_valid = 0;
1963         for (i = 0; i < crypt_stat->key_size; i++)
1964                 encrypted_session_key_valid |=
1965                         auth_tok->session_key.encrypted_key[i];
1966         if (encrypted_session_key_valid) {
1967                 memcpy(key_rec->enc_key,
1968                        auth_tok->session_key.encrypted_key,
1969                        auth_tok->session_key.encrypted_key_size);
1970                 goto encrypted_session_key_set;
1971         }
1972         if (auth_tok->session_key.encrypted_key_size == 0)
1973                 auth_tok->session_key.encrypted_key_size =
1974                         auth_tok->token.private_key.key_size;
1975         rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
1976         if (rc) {
1977                 printk(KERN_ERR "Failed to encrypt session key via a key "
1978                        "module; rc = [%d]\n", rc);
1979                 goto out;
1980         }
1981         if (ecryptfs_verbosity > 0) {
1982                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
1983                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
1984         }
1985 encrypted_session_key_set:
1986         /* This format is inspired by OpenPGP; see RFC 2440
1987          * packet tag 1 */
1988         max_packet_size = (1                         /* Tag 1 identifier */
1989                            + 3                       /* Max Tag 1 packet size */
1990                            + 1                       /* Version */
1991                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
1992                            + 1                       /* Cipher identifier */
1993                            + key_rec->enc_key_size); /* Encrypted key size */
1994         if (max_packet_size > (*remaining_bytes)) {
1995                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1996                        "need up to [%td] bytes, but there are only [%td] "
1997                        "available\n", max_packet_size, (*remaining_bytes));
1998                 rc = -EINVAL;
1999                 goto out;
2000         }
2001         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2002         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2003                                           (max_packet_size - 4),
2004                                           &packet_size_length);
2005         if (rc) {
2006                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2007                                 "header; cannot generate packet length\n");
2008                 goto out;
2009         }
2010         (*packet_size) += packet_size_length;
2011         dest[(*packet_size)++] = 0x03; /* version 3 */
2012         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2013         (*packet_size) += ECRYPTFS_SIG_SIZE;
2014         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2015         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2016                key_rec->enc_key_size);
2017         (*packet_size) += key_rec->enc_key_size;
2018 out:
2019         if (rc)
2020                 (*packet_size) = 0;
2021         else
2022                 (*remaining_bytes) -= (*packet_size);
2023         return rc;
2024 }
2025
2026 /**
2027  * write_tag_11_packet
2028  * @dest: Target into which Tag 11 packet is to be written
2029  * @remaining_bytes: Maximum packet length
2030  * @contents: Byte array of contents to copy in
2031  * @contents_length: Number of bytes in contents
2032  * @packet_length: Length of the Tag 11 packet written; zero on error
2033  *
2034  * Returns zero on success; non-zero on error.
2035  */
2036 static int
2037 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2038                     size_t contents_length, size_t *packet_length)
2039 {
2040         size_t packet_size_length;
2041         size_t max_packet_size;
2042         int rc = 0;
2043
2044         (*packet_length) = 0;
2045         /* This format is inspired by OpenPGP; see RFC 2440
2046          * packet tag 11 */
2047         max_packet_size = (1                   /* Tag 11 identifier */
2048                            + 3                 /* Max Tag 11 packet size */
2049                            + 1                 /* Binary format specifier */
2050                            + 1                 /* Filename length */
2051                            + 8                 /* Filename ("_CONSOLE") */
2052                            + 4                 /* Modification date */
2053                            + contents_length); /* Literal data */
2054         if (max_packet_size > (*remaining_bytes)) {
2055                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2056                        "need up to [%td] bytes, but there are only [%td] "
2057                        "available\n", max_packet_size, (*remaining_bytes));
2058                 rc = -EINVAL;
2059                 goto out;
2060         }
2061         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2062         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2063                                           (max_packet_size - 4),
2064                                           &packet_size_length);
2065         if (rc) {
2066                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2067                        "generate packet length. rc = [%d]\n", rc);
2068                 goto out;
2069         }
2070         (*packet_length) += packet_size_length;
2071         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2072         dest[(*packet_length)++] = 8;
2073         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2074         (*packet_length) += 8;
2075         memset(&dest[(*packet_length)], 0x00, 4);
2076         (*packet_length) += 4;
2077         memcpy(&dest[(*packet_length)], contents, contents_length);
2078         (*packet_length) += contents_length;
2079  out:
2080         if (rc)
2081                 (*packet_length) = 0;
2082         else
2083                 (*remaining_bytes) -= (*packet_length);
2084         return rc;
2085 }
2086
2087 /**
2088  * write_tag_3_packet
2089  * @dest: Buffer into which to write the packet
2090  * @remaining_bytes: Maximum number of bytes that can be written
2091  * @auth_tok: Authentication token
2092  * @crypt_stat: The cryptographic context
2093  * @key_rec: encrypted key
2094  * @packet_size: This function will write the number of bytes that end
2095  *               up constituting the packet; set to zero on error
2096  *
2097  * Returns zero on success; non-zero on error.
2098  */
2099 static int
2100 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2101                    struct ecryptfs_auth_tok *auth_tok,
2102                    struct ecryptfs_crypt_stat *crypt_stat,
2103                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2104 {
2105         size_t i;
2106         size_t encrypted_session_key_valid = 0;
2107         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2108         struct scatterlist dst_sg[2];
2109         struct scatterlist src_sg[2];
2110         struct mutex *tfm_mutex = NULL;
2111         u8 cipher_code;
2112         size_t packet_size_length;
2113         size_t max_packet_size;
2114         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2115                 crypt_stat->mount_crypt_stat;
2116         struct blkcipher_desc desc = {
2117                 .tfm = NULL,
2118                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2119         };
2120         int rc = 0;
2121
2122         (*packet_size) = 0;
2123         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2124                           ECRYPTFS_SIG_SIZE);
2125         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2126                                                         crypt_stat->cipher);
2127         if (unlikely(rc)) {
2128                 printk(KERN_ERR "Internal error whilst attempting to get "
2129                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2130                        crypt_stat->cipher, rc);
2131                 goto out;
2132         }
2133         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2134                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2135
2136                 printk(KERN_WARNING "No key size specified at mount; "
2137                        "defaulting to [%d]\n", alg->max_keysize);
2138                 mount_crypt_stat->global_default_cipher_key_size =
2139                         alg->max_keysize;
2140         }
2141         if (crypt_stat->key_size == 0)
2142                 crypt_stat->key_size =
2143                         mount_crypt_stat->global_default_cipher_key_size;
2144         if (auth_tok->session_key.encrypted_key_size == 0)
2145                 auth_tok->session_key.encrypted_key_size =
2146                         crypt_stat->key_size;
2147         if (crypt_stat->key_size == 24
2148             && strcmp("aes", crypt_stat->cipher) == 0) {
2149                 memset((crypt_stat->key + 24), 0, 8);
2150                 auth_tok->session_key.encrypted_key_size = 32;
2151         } else
2152                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2153         key_rec->enc_key_size =
2154                 auth_tok->session_key.encrypted_key_size;
2155         encrypted_session_key_valid = 0;
2156         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2157                 encrypted_session_key_valid |=
2158                         auth_tok->session_key.encrypted_key[i];
2159         if (encrypted_session_key_valid) {
2160                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2161                                 "using auth_tok->session_key.encrypted_key, "
2162                                 "where key_rec->enc_key_size = [%d]\n",
2163                                 key_rec->enc_key_size);
2164                 memcpy(key_rec->enc_key,
2165                        auth_tok->session_key.encrypted_key,
2166                        key_rec->enc_key_size);
2167                 goto encrypted_session_key_set;
2168         }
2169         if (auth_tok->token.password.flags &
2170             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2171                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2172                                 "session key encryption key of size [%d]\n",
2173                                 auth_tok->token.password.
2174                                 session_key_encryption_key_bytes);
2175                 memcpy(session_key_encryption_key,
2176                        auth_tok->token.password.session_key_encryption_key,
2177                        crypt_stat->key_size);
2178                 ecryptfs_printk(KERN_DEBUG,
2179                                 "Cached session key " "encryption key: \n");
2180                 if (ecryptfs_verbosity > 0)
2181                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2182         }
2183         if (unlikely(ecryptfs_verbosity > 0)) {
2184                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2185                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2186         }
2187         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2188                                  src_sg, 2);
2189         if (rc < 1 || rc > 2) {
2190                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2191                                 "for crypt_stat session key; expected rc = 1; "
2192                                 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
2193                                 rc, key_rec->enc_key_size);
2194                 rc = -ENOMEM;
2195                 goto out;
2196         }
2197         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2198                                  dst_sg, 2);
2199         if (rc < 1 || rc > 2) {
2200                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2201                                 "for crypt_stat encrypted session key; "
2202                                 "expected rc = 1; got rc = [%d]. "
2203                                 "key_rec->enc_key_size = [%d]\n", rc,
2204                                 key_rec->enc_key_size);
2205                 rc = -ENOMEM;
2206                 goto out;
2207         }
2208         mutex_lock(tfm_mutex);
2209         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2210                                      crypt_stat->key_size);
2211         if (rc < 0) {
2212                 mutex_unlock(tfm_mutex);
2213                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2214                                 "context; rc = [%d]\n", rc);
2215                 goto out;
2216         }
2217         rc = 0;
2218         ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
2219                         crypt_stat->key_size);
2220         rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2221                                       (*key_rec).enc_key_size);
2222         mutex_unlock(tfm_mutex);
2223         if (rc) {
2224                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2225                 goto out;
2226         }
2227         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2228         if (ecryptfs_verbosity > 0) {
2229                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
2230                                 key_rec->enc_key_size);
2231                 ecryptfs_dump_hex(key_rec->enc_key,
2232                                   key_rec->enc_key_size);
2233         }
2234 encrypted_session_key_set:
2235         /* This format is inspired by OpenPGP; see RFC 2440
2236          * packet tag 3 */
2237         max_packet_size = (1                         /* Tag 3 identifier */
2238                            + 3                       /* Max Tag 3 packet size */
2239                            + 1                       /* Version */
2240                            + 1                       /* Cipher code */
2241                            + 1                       /* S2K specifier */
2242                            + 1                       /* Hash identifier */
2243                            + ECRYPTFS_SALT_SIZE      /* Salt */
2244                            + 1                       /* Hash iterations */
2245                            + key_rec->enc_key_size); /* Encrypted key size */
2246         if (max_packet_size > (*remaining_bytes)) {
2247                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2248                        "there are only [%td] available\n", max_packet_size,
2249                        (*remaining_bytes));
2250                 rc = -EINVAL;
2251                 goto out;
2252         }
2253         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2254         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2255          * to get the number of octets in the actual Tag 3 packet */
2256         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2257                                           (max_packet_size - 4),
2258                                           &packet_size_length);
2259         if (rc) {
2260                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2261                        "generate packet length. rc = [%d]\n", rc);
2262                 goto out;
2263         }
2264         (*packet_size) += packet_size_length;
2265         dest[(*packet_size)++] = 0x04; /* version 4 */
2266         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2267          * specified with strings */
2268         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2269                                                       crypt_stat->key_size);
2270         if (cipher_code == 0) {
2271                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2272                                 "cipher [%s]\n", crypt_stat->cipher);
2273                 rc = -EINVAL;
2274                 goto out;
2275         }
2276         dest[(*packet_size)++] = cipher_code;
2277         dest[(*packet_size)++] = 0x03;  /* S2K */
2278         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2279         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2280                ECRYPTFS_SALT_SIZE);
2281         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2282         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2283         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2284                key_rec->enc_key_size);
2285         (*packet_size) += key_rec->enc_key_size;
2286 out:
2287         if (rc)
2288                 (*packet_size) = 0;
2289         else
2290                 (*remaining_bytes) -= (*packet_size);
2291         return rc;
2292 }
2293
2294 struct kmem_cache *ecryptfs_key_record_cache;
2295
2296 /**
2297  * ecryptfs_generate_key_packet_set
2298  * @dest_base: Virtual address from which to write the key record set
2299  * @crypt_stat: The cryptographic context from which the
2300  *              authentication tokens will be retrieved
2301  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2302  *                   for the global parameters
2303  * @len: The amount written
2304  * @max: The maximum amount of data allowed to be written
2305  *
2306  * Generates a key packet set and writes it to the virtual address
2307  * passed in.
2308  *
2309  * Returns zero on success; non-zero on error.
2310  */
2311 int
2312 ecryptfs_generate_key_packet_set(char *dest_base,
2313                                  struct ecryptfs_crypt_stat *crypt_stat,
2314                                  struct dentry *ecryptfs_dentry, size_t *len,
2315                                  size_t max)
2316 {
2317         struct ecryptfs_auth_tok *auth_tok;
2318         struct ecryptfs_global_auth_tok *global_auth_tok;
2319         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2320                 &ecryptfs_superblock_to_private(
2321                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2322         size_t written;
2323         struct ecryptfs_key_record *key_rec;
2324         struct ecryptfs_key_sig *key_sig;
2325         int rc = 0;
2326
2327         (*len) = 0;
2328         mutex_lock(&crypt_stat->keysig_list_mutex);
2329         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2330         if (!key_rec) {
2331                 rc = -ENOMEM;
2332                 goto out;
2333         }
2334         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2335                             crypt_stat_list) {
2336                 memset(key_rec, 0, sizeof(*key_rec));
2337                 rc = ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
2338                                                            mount_crypt_stat,
2339                                                            key_sig->keysig);
2340                 if (rc) {
2341                         printk(KERN_ERR "Error attempting to get the global "
2342                                "auth_tok; rc = [%d]\n", rc);
2343                         goto out_free;
2344                 }
2345                 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
2346                         printk(KERN_WARNING
2347                                "Skipping invalid auth tok with sig = [%s]\n",
2348                                global_auth_tok->sig);
2349                         continue;
2350                 }
2351                 auth_tok = global_auth_tok->global_auth_tok;
2352                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2353                         rc = write_tag_3_packet((dest_base + (*len)),
2354                                                 &max, auth_tok,
2355                                                 crypt_stat, key_rec,
2356                                                 &written);
2357                         if (rc) {
2358                                 ecryptfs_printk(KERN_WARNING, "Error "
2359                                                 "writing tag 3 packet\n");
2360                                 goto out_free;
2361                         }
2362                         (*len) += written;
2363                         /* Write auth tok signature packet */
2364                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2365                                                  key_rec->sig,
2366                                                  ECRYPTFS_SIG_SIZE, &written);
2367                         if (rc) {
2368                                 ecryptfs_printk(KERN_ERR, "Error writing "
2369                                                 "auth tok signature packet\n");
2370                                 goto out_free;
2371                         }
2372                         (*len) += written;
2373                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2374                         rc = write_tag_1_packet(dest_base + (*len),
2375                                                 &max, auth_tok,
2376                                                 crypt_stat, key_rec, &written);
2377                         if (rc) {
2378                                 ecryptfs_printk(KERN_WARNING, "Error "
2379                                                 "writing tag 1 packet\n");
2380                                 goto out_free;
2381                         }
2382                         (*len) += written;
2383                 } else {
2384                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2385                                         "authentication token type\n");
2386                         rc = -EINVAL;
2387                         goto out_free;
2388                 }
2389         }
2390         if (likely(max > 0)) {
2391                 dest_base[(*len)] = 0x00;
2392         } else {
2393                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2394                 rc = -EIO;
2395         }
2396 out_free:
2397         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2398 out:
2399         if (rc)
2400                 (*len) = 0;
2401         mutex_unlock(&crypt_stat->keysig_list_mutex);
2402         return rc;
2403 }
2404
2405 struct kmem_cache *ecryptfs_key_sig_cache;
2406
2407 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2408 {
2409         struct ecryptfs_key_sig *new_key_sig;
2410
2411         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2412         if (!new_key_sig) {
2413                 printk(KERN_ERR
2414                        "Error allocating from ecryptfs_key_sig_cache\n");
2415                 return -ENOMEM;
2416         }
2417         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2418         /* Caller must hold keysig_list_mutex */
2419         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2420
2421         return 0;
2422 }
2423
2424 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2425
2426 int
2427 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2428                              char *sig, u32 global_auth_tok_flags)
2429 {
2430         struct ecryptfs_global_auth_tok *new_auth_tok;
2431         int rc = 0;
2432
2433         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2434                                         GFP_KERNEL);
2435         if (!new_auth_tok) {
2436                 rc = -ENOMEM;
2437                 printk(KERN_ERR "Error allocating from "
2438                        "ecryptfs_global_auth_tok_cache\n");
2439                 goto out;
2440         }
2441         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2442         new_auth_tok->flags = global_auth_tok_flags;
2443         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2444         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2445         list_add(&new_auth_tok->mount_crypt_stat_list,
2446                  &mount_crypt_stat->global_auth_tok_list);
2447         mount_crypt_stat->num_global_auth_toks++;
2448         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2449 out:
2450         return rc;
2451 }
2452