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   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 "ecryptfs_kernel.h"
  36
  37 /**
  38  * request_key returned an error instead of a valid key address;
  39  * determine the type of error, make appropriate log entries, and
  40  * return an error code.
  41  */
  42 int process_request_key_err(long err_code)
  43 {
  44         int rc = 0;
  45
  46         switch (err_code) {
  47         case ENOKEY:
  48                 ecryptfs_printk(KERN_WARNING, "No key\n");
  49                 rc = -ENOENT;
  50                 break;
  51         case EKEYEXPIRED:
  52                 ecryptfs_printk(KERN_WARNING, "Key expired\n");
  53                 rc = -ETIME;
  54                 break;
  55         case EKEYREVOKED:
  56                 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
  57                 rc = -EINVAL;
  58                 break;
  59         default:
  60                 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
  61                                 "[0x%.16x]\n", err_code);
  62                 rc = -EINVAL;
  63         }
  64         return rc;
  65 }
  66
  67 /**
  68  * parse_packet_length
  69  * @data: Pointer to memory containing length at offset
  70  * @size: This function writes the decoded size to this memory
  71  *        address; zero on error
  72  * @length_size: The number of bytes occupied by the encoded length
  73  *
  74  * Returns Zero on success
  75  */
  76 static int parse_packet_length(unsigned char *data, size_t *size,
  77                                size_t *length_size)
  78 {
  79         int rc = 0;
  80
  81         (*length_size) = 0;
  82         (*size) = 0;
  83         if (data[0] < 192) {
  84                 /* One-byte length */
  85                 (*size) = (unsigned char)data[0];
  86                 (*length_size) = 1;
  87         } else if (data[0] < 224) {
  88                 /* Two-byte length */
  89                 (*size) = (((unsigned char)(data[0]) - 192) * 256);
  90                 (*size) += ((unsigned char)(data[1]) + 192);
  91                 (*length_size) = 2;
  92         } else if (data[0] == 255) {
  93                 /* Five-byte length; we're not supposed to see this */
  94                 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
  95                                 "supported\n");
  96                 rc = -EINVAL;
  97                 goto out;
  98         } else {
  99                 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
 100                 rc = -EINVAL;
 101                 goto out;
 102         }
 103 out:
 104         return rc;
 105 }
 106
 107 /**
 108  * write_packet_length
 109  * @dest: The byte array target into which to write the
 110  *       length. Must have at least 5 bytes allocated.
 111  * @size: The length to write.
 112  * @packet_size_length: The number of bytes used to encode the
 113  *                      packet length is written to this address.
 114  *
 115  * Returns zero on success; non-zero on error.
 116  */
 117 static int write_packet_length(char *dest, size_t size,
 118                                size_t *packet_size_length)
 119 {
 120         int rc = 0;
 121
 122         if (size < 192) {
 123                 dest[0] = size;
 124                 (*packet_size_length) = 1;
 125         } else if (size < 65536) {
 126                 dest[0] = (((size - 192) / 256) + 192);
 127                 dest[1] = ((size - 192) % 256);
 128                 (*packet_size_length) = 2;
 129         } else {
 130                 rc = -EINVAL;
 131                 ecryptfs_printk(KERN_WARNING,
 132                                 "Unsupported packet size: [%d]\n", size);
 133         }
 134         return rc;
 135 }
 136
 137 static int
 138 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
 139                     char **packet, size_t *packet_len)
 140 {
 141         size_t i = 0;
 142         size_t data_len;
 143         size_t packet_size_len;
 144         char *message;
 145         int rc;
 146
 147         /*
 148          *              ***** TAG 64 Packet Format *****
 149          *    | Content Type                       | 1 byte       |
 150          *    | Key Identifier Size                | 1 or 2 bytes |
 151          *    | Key Identifier                     | arbitrary    |
 152          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 153          *    | Encrypted File Encryption Key      | arbitrary    |
 154          */
 155         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
 156                     + session_key->encrypted_key_size);
 157         *packet = kmalloc(data_len, GFP_KERNEL);
 158         message = *packet;
 159         if (!message) {
 160                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 161                 rc = -ENOMEM;
 162                 goto out;
 163         }
 164         message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
 165         rc = write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 166                                  &packet_size_len);
 167         if (rc) {
 168                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 169                                 "header; cannot generate packet length\n");
 170                 goto out;
 171         }
 172         i += packet_size_len;
 173         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 174         i += ECRYPTFS_SIG_SIZE_HEX;
 175         rc = write_packet_length(&message[i], session_key->encrypted_key_size,
 176                                  &packet_size_len);
 177         if (rc) {
 178                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 179                                 "header; cannot generate packet length\n");
 180                 goto out;
 181         }
 182         i += packet_size_len;
 183         memcpy(&message[i], session_key->encrypted_key,
 184                session_key->encrypted_key_size);
 185         i += session_key->encrypted_key_size;
 186         *packet_len = i;
 187 out:
 188         return rc;
 189 }
 190
 191 static int
 192 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u16 *cipher_code,
 193                     struct ecryptfs_message *msg)
 194 {
 195         size_t i = 0;
 196         char *data;
 197         size_t data_len;
 198         size_t m_size;
 199         size_t message_len;
 200         u16 checksum = 0;
 201         u16 expected_checksum = 0;
 202         int rc;
 203
 204         /*
 205          *              ***** TAG 65 Packet Format *****
 206          *         | Content Type             | 1 byte       |
 207          *         | Status Indicator         | 1 byte       |
 208          *         | File Encryption Key Size | 1 or 2 bytes |
 209          *         | File Encryption Key      | arbitrary    |
 210          */
 211         message_len = msg->data_len;
 212         data = msg->data;
 213         if (message_len < 4) {
 214                 rc = -EIO;
 215                 goto out;
 216         }
 217         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
 218                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
 219                 rc = -EIO;
 220                 goto out;
 221         }
 222         if (data[i++]) {
 223                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
 224                                 "[%d]\n", data[i-1]);
 225                 rc = -EIO;
 226                 goto out;
 227         }
 228         rc = parse_packet_length(&data[i], &m_size, &data_len);
 229         if (rc) {
 230                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 231                                 "rc = [%d]\n", rc);
 232                 goto out;
 233         }
 234         i += data_len;
 235         if (message_len < (i + m_size)) {
 236                 ecryptfs_printk(KERN_ERR, "The received netlink message is "
 237                                 "shorter than expected\n");
 238                 rc = -EIO;
 239                 goto out;
 240         }
 241         if (m_size < 3) {
 242                 ecryptfs_printk(KERN_ERR,
 243                                 "The decrypted key is not long enough to "
 244                                 "include a cipher code and checksum\n");
 245                 rc = -EIO;
 246                 goto out;
 247         }
 248         *cipher_code = data[i++];
 249         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
 250         session_key->decrypted_key_size = m_size - 3;
 251         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
 252                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
 253                                 "the maximum key size [%d]\n",
 254                                 session_key->decrypted_key_size,
 255                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 256                 rc = -EIO;
 257                 goto out;
 258         }
 259         memcpy(session_key->decrypted_key, &data[i],
 260                session_key->decrypted_key_size);
 261         i += session_key->decrypted_key_size;
 262         expected_checksum += (unsigned char)(data[i++]) << 8;
 263         expected_checksum += (unsigned char)(data[i++]);
 264         for (i = 0; i < session_key->decrypted_key_size; i++)
 265                 checksum += session_key->decrypted_key[i];
 266         if (expected_checksum != checksum) {
 267                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
 268                                 "encryption  key; expected [%x]; calculated "
 269                                 "[%x]\n", expected_checksum, checksum);
 270                 rc = -EIO;
 271         }
 272 out:
 273         return rc;
 274 }
 275
 276
 277 static int
 278 write_tag_66_packet(char *signature, size_t cipher_code,
 279                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
 280                     size_t *packet_len)
 281 {
 282         size_t i = 0;
 283         size_t j;
 284         size_t data_len;
 285         size_t checksum = 0;
 286         size_t packet_size_len;
 287         char *message;
 288         int rc;
 289
 290         /*
 291          *              ***** TAG 66 Packet Format *****
 292          *         | Content Type             | 1 byte       |
 293          *         | Key Identifier Size      | 1 or 2 bytes |
 294          *         | Key Identifier           | arbitrary    |
 295          *         | File Encryption Key Size | 1 or 2 bytes |
 296          *         | File Encryption Key      | arbitrary    |
 297          */
 298         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
 299         *packet = kmalloc(data_len, GFP_KERNEL);
 300         message = *packet;
 301         if (!message) {
 302                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 303                 rc = -ENOMEM;
 304                 goto out;
 305         }
 306         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
 307         rc = write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 308                                  &packet_size_len);
 309         if (rc) {
 310                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 311                                 "header; cannot generate packet length\n");
 312                 goto out;
 313         }
 314         i += packet_size_len;
 315         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 316         i += ECRYPTFS_SIG_SIZE_HEX;
 317         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
 318         rc = write_packet_length(&message[i], crypt_stat->key_size + 3,
 319                                  &packet_size_len);
 320         if (rc) {
 321                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 322                                 "header; cannot generate packet length\n");
 323                 goto out;
 324         }
 325         i += packet_size_len;
 326         message[i++] = cipher_code;
 327         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
 328         i += crypt_stat->key_size;
 329         for (j = 0; j < crypt_stat->key_size; j++)
 330                 checksum += crypt_stat->key[j];
 331         message[i++] = (checksum / 256) % 256;
 332         message[i++] = (checksum % 256);
 333         *packet_len = i;
 334 out:
 335         return rc;
 336 }
 337
 338 static int
 339 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
 340                     struct ecryptfs_message *msg)
 341 {
 342         size_t i = 0;
 343         char *data;
 344         size_t data_len;
 345         size_t message_len;
 346         int rc;
 347
 348         /*
 349          *              ***** TAG 65 Packet Format *****
 350          *    | Content Type                       | 1 byte       |
 351          *    | Status Indicator                   | 1 byte       |
 352          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 353          *    | Encrypted File Encryption Key      | arbitrary    |
 354          */
 355         message_len = msg->data_len;
 356         data = msg->data;
 357         /* verify that everything through the encrypted FEK size is present */
 358         if (message_len < 4) {
 359                 rc = -EIO;
 360                 goto out;
 361         }
 362         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
 363                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_67\n");
 364                 rc = -EIO;
 365                 goto out;
 366         }
 367         if (data[i++]) {
 368                 ecryptfs_printk(KERN_ERR, "Status indicator has non zero value"
 369                                 " [%d]\n", data[i-1]);
 370                 rc = -EIO;
 371                 goto out;
 372         }
 373         rc = parse_packet_length(&data[i], &key_rec->enc_key_size, &data_len);
 374         if (rc) {
 375                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 376                                 "rc = [%d]\n", rc);
 377                 goto out;
 378         }
 379         i += data_len;
 380         if (message_len < (i + key_rec->enc_key_size)) {
 381                 ecryptfs_printk(KERN_ERR, "message_len [%d]; max len is [%d]\n",
 382                                 message_len, (i + key_rec->enc_key_size));
 383                 rc = -EIO;
 384                 goto out;
 385         }
 386         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 387                 ecryptfs_printk(KERN_ERR, "Encrypted key_size [%d] larger than "
 388                                 "the maximum key size [%d]\n",
 389                                 key_rec->enc_key_size,
 390                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 391                 rc = -EIO;
 392                 goto out;
 393         }
 394         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
 395 out:
 396         return rc;
 397 }
 398
 399 /**
 400  * decrypt_pki_encrypted_session_key - Decrypt the session key with
 401  * the given auth_tok.
 402  *
 403  * Returns Zero on success; non-zero error otherwise.
 404  */
 405 static int
 406 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
 407                                   struct ecryptfs_crypt_stat *crypt_stat)
 408 {
 409         u16 cipher_code = 0;
 410         struct ecryptfs_msg_ctx *msg_ctx;
 411         struct ecryptfs_message *msg = NULL;
 412         char *auth_tok_sig;
 413         char *netlink_message;
 414         size_t netlink_message_length;
 415         int rc;
 416
 417         if ((rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok))) {
 418                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
 419                        auth_tok->token_type);
 420                 goto out;
 421         }
 422         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
 423                                  &netlink_message, &netlink_message_length);
 424         if (rc) {
 425                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet");
 426                 goto out;
 427         }
 428         rc = ecryptfs_send_message(ecryptfs_transport, netlink_message,
 429                                    netlink_message_length, &msg_ctx);
 430         if (rc) {
 431                 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
 432                 goto out;
 433         }
 434         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
 435         if (rc) {
 436                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
 437                                 "from the user space daemon\n");
 438                 rc = -EIO;
 439                 goto out;
 440         }
 441         rc = parse_tag_65_packet(&(auth_tok->session_key),
 442                                  &cipher_code, msg);
 443         if (rc) {
 444                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
 445                        rc);
 446                 goto out;
 447         }
 448         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 449         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
 450                auth_tok->session_key.decrypted_key_size);
 451         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
 452         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
 453         if (rc) {
 454                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
 455                                 cipher_code)
 456                 goto out;
 457         }
 458         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
 459         if (ecryptfs_verbosity > 0) {
 460                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
 461                 ecryptfs_dump_hex(crypt_stat->key,
 462                                   crypt_stat->key_size);
 463         }
 464 out:
 465         if (msg)
 466                 kfree(msg);
 467         return rc;
 468 }
 469
 470 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
 471 {
 472         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 473         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
 474
 475         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
 476                                  auth_tok_list_head, list) {
 477                 list_del(&auth_tok_list_item->list);
 478                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 479                                 auth_tok_list_item);
 480         }
 481 }
 482
 483 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
 484
 485 /**
 486  * parse_tag_1_packet
 487  * @crypt_stat: The cryptographic context to modify based on packet
 488  *              contents.
 489  * @data: The raw bytes of the packet.
 490  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
 491  *                 a new authentication token will be placed at the end
 492  *                 of this list for this packet.
 493  * @new_auth_tok: Pointer to a pointer to memory that this function
 494  *                allocates; sets the memory address of the pointer to
 495  *                NULL on error. This object is added to the
 496  *                auth_tok_list.
 497  * @packet_size: This function writes the size of the parsed packet
 498  *               into this memory location; zero on error.
 499  *
 500  * Returns zero on success; non-zero on error.
 501  */
 502 static int
 503 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
 504                    unsigned char *data, struct list_head *auth_tok_list,
 505                    struct ecryptfs_auth_tok **new_auth_tok,
 506                    size_t *packet_size, size_t max_packet_size)
 507 {
 508         size_t body_size;
 509         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 510         size_t length_size;
 511         int rc = 0;
 512
 513         (*packet_size) = 0;
 514         (*new_auth_tok) = NULL;
 515         /**
 516          * This format is inspired by OpenPGP; see RFC 2440
 517          * packet tag 1
 518          *
 519          * Tag 1 identifier (1 byte)
 520          * Max Tag 1 packet size (max 3 bytes)
 521          * Version (1 byte)
 522          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
 523          * Cipher identifier (1 byte)
 524          * Encrypted key size (arbitrary)
 525          *
 526          * 12 bytes minimum packet size
 527          */
 528         if (unlikely(max_packet_size < 12)) {
 529                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
 530                 rc = -EINVAL;
 531                 goto out;
 532         }
 533         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
 534                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
 535                        ECRYPTFS_TAG_1_PACKET_TYPE);
 536                 rc = -EINVAL;
 537                 goto out;
 538         }
 539         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
 540          * at end of function upon failure */
 541         auth_tok_list_item =
 542                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
 543                                   GFP_KERNEL);
 544         if (!auth_tok_list_item) {
 545                 printk(KERN_ERR "Unable to allocate memory\n");
 546                 rc = -ENOMEM;
 547                 goto out;
 548         }
 549         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
 550         if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
 551                                       &length_size))) {
 552                 printk(KERN_WARNING "Error parsing packet length; "
 553                        "rc = [%d]\n", rc);
 554                 goto out_free;
 555         }
 556         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
 557                 printk(KERN_WARNING "Invalid body size ([%d])\n", body_size);
 558                 rc = -EINVAL;
 559                 goto out_free;
 560         }
 561         (*packet_size) += length_size;
 562         if (unlikely((*packet_size) + body_size > max_packet_size)) {
 563                 printk(KERN_WARNING "Packet size exceeds max\n");
 564                 rc = -EINVAL;
 565                 goto out_free;
 566         }
 567         if (unlikely(data[(*packet_size)++] != 0x03)) {
 568                 printk(KERN_WARNING "Unknown version number [%d]\n",
 569                        data[(*packet_size) - 1]);
 570                 rc = -EINVAL;
 571                 goto out_free;
 572         }
 573         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
 574                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
 575         *packet_size += ECRYPTFS_SIG_SIZE;
 576         /* This byte is skipped because the kernel does not need to
 577          * know which public key encryption algorithm was used */
 578         (*packet_size)++;
 579         (*new_auth_tok)->session_key.encrypted_key_size =
 580                 body_size - (ECRYPTFS_SIG_SIZE + 2);
 581         if ((*new_auth_tok)->session_key.encrypted_key_size
 582             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 583                 printk(KERN_WARNING "Tag 1 packet contains key larger "
 584                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
 585                 rc = -EINVAL;
 586                 goto out;
 587         }
 588         memcpy((*new_auth_tok)->session_key.encrypted_key,
 589                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
 590         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
 591         (*new_auth_tok)->session_key.flags &=
 592                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 593         (*new_auth_tok)->session_key.flags |=
 594                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
 595         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
 596         (*new_auth_tok)->flags = 0;
 597         (*new_auth_tok)->session_key.flags &=
 598                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
 599         (*new_auth_tok)->session_key.flags &=
 600                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
 601         list_add(&auth_tok_list_item->list, auth_tok_list);
 602         goto out;
 603 out_free:
 604         (*new_auth_tok) = NULL;
 605         memset(auth_tok_list_item, 0,
 606                sizeof(struct ecryptfs_auth_tok_list_item));
 607         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 608                         auth_tok_list_item);
 609 out:
 610         if (rc)
 611                 (*packet_size) = 0;
 612         return rc;
 613 }
 614
 615 /**
 616  * parse_tag_3_packet
 617  * @crypt_stat: The cryptographic context to modify based on packet
 618  *              contents.
 619  * @data: The raw bytes of the packet.
 620  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
 621  *                 a new authentication token will be placed at the end
 622  *                 of this list for this packet.
 623  * @new_auth_tok: Pointer to a pointer to memory that this function
 624  *                allocates; sets the memory address of the pointer to
 625  *                NULL on error. This object is added to the
 626  *                auth_tok_list.
 627  * @packet_size: This function writes the size of the parsed packet
 628  *               into this memory location; zero on error.
 629  * @max_packet_size: maximum number of bytes to parse
 630  *
 631  * Returns zero on success; non-zero on error.
 632  */
 633 static int
 634 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
 635                    unsigned char *data, struct list_head *auth_tok_list,
 636                    struct ecryptfs_auth_tok **new_auth_tok,
 637                    size_t *packet_size, size_t max_packet_size)
 638 {
 639         size_t body_size;
 640         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 641         size_t length_size;
 642         int rc = 0;
 643
 644         (*packet_size) = 0;
 645         (*new_auth_tok) = NULL;
 646         /**
 647          *This format is inspired by OpenPGP; see RFC 2440
 648          * packet tag 3
 649          *
 650          * Tag 3 identifier (1 byte)
 651          * Max Tag 3 packet size (max 3 bytes)
 652          * Version (1 byte)
 653          * Cipher code (1 byte)
 654          * S2K specifier (1 byte)
 655          * Hash identifier (1 byte)
 656          * Salt (ECRYPTFS_SALT_SIZE)
 657          * Hash iterations (1 byte)
 658          * Encrypted key (arbitrary)
 659          *
 660          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
 661          */
 662         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
 663                 printk(KERN_ERR "Max packet size too large\n");
 664                 rc = -EINVAL;
 665                 goto out;
 666         }
 667         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
 668                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
 669                        ECRYPTFS_TAG_3_PACKET_TYPE);
 670                 rc = -EINVAL;
 671                 goto out;
 672         }
 673         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
 674          * at end of function upon failure */
 675         auth_tok_list_item =
 676             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
 677         if (!auth_tok_list_item) {
 678                 printk(KERN_ERR "Unable to allocate memory\n");
 679                 rc = -ENOMEM;
 680                 goto out;
 681         }
 682         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
 683         if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
 684                                       &length_size))) {
 685                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
 686                        rc);
 687                 goto out_free;
 688         }
 689         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
 690                 printk(KERN_WARNING "Invalid body size ([%d])\n", body_size);
 691                 rc = -EINVAL;
 692                 goto out_free;
 693         }
 694         (*packet_size) += length_size;
 695         if (unlikely((*packet_size) + body_size > max_packet_size)) {
 696                 printk(KERN_ERR "Packet size exceeds max\n");
 697                 rc = -EINVAL;
 698                 goto out_free;
 699         }
 700         (*new_auth_tok)->session_key.encrypted_key_size =
 701                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
 702         if (unlikely(data[(*packet_size)++] != 0x04)) {
 703                 printk(KERN_WARNING "Unknown version number [%d]\n",
 704                        data[(*packet_size) - 1]);
 705                 rc = -EINVAL;
 706                 goto out_free;
 707         }
 708         ecryptfs_cipher_code_to_string(crypt_stat->cipher,
 709                                        (u16)data[(*packet_size)]);
 710         /* A little extra work to differentiate among the AES key
 711          * sizes; see RFC2440 */
 712         switch(data[(*packet_size)++]) {
 713         case RFC2440_CIPHER_AES_192:
 714                 crypt_stat->key_size = 24;
 715                 break;
 716         default:
 717                 crypt_stat->key_size =
 718                         (*new_auth_tok)->session_key.encrypted_key_size;
 719         }
 720         ecryptfs_init_crypt_ctx(crypt_stat);
 721         if (unlikely(data[(*packet_size)++] != 0x03)) {
 722                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
 723                 rc = -ENOSYS;
 724                 goto out_free;
 725         }
 726         /* TODO: finish the hash mapping */
 727         switch (data[(*packet_size)++]) {
 728         case 0x01: /* See RFC2440 for these numbers and their mappings */
 729                 /* Choose MD5 */
 730                 memcpy((*new_auth_tok)->token.password.salt,
 731                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
 732                 (*packet_size) += ECRYPTFS_SALT_SIZE;
 733                 /* This conversion was taken straight from RFC2440 */
 734                 (*new_auth_tok)->token.password.hash_iterations =
 735                         ((u32) 16 + (data[(*packet_size)] & 15))
 736                                 << ((data[(*packet_size)] >> 4) + 6);
 737                 (*packet_size)++;
 738                 /* Friendly reminder:
 739                  * (*new_auth_tok)->session_key.encrypted_key_size =
 740                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
 741                 memcpy((*new_auth_tok)->session_key.encrypted_key,
 742                        &data[(*packet_size)],
 743                        (*new_auth_tok)->session_key.encrypted_key_size);
 744                 (*packet_size) +=
 745                         (*new_auth_tok)->session_key.encrypted_key_size;
 746                 (*new_auth_tok)->session_key.flags &=
 747                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 748                 (*new_auth_tok)->session_key.flags |=
 749                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
 750                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
 751                 break;
 752         default:
 753                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
 754                                 "[%d]\n", data[(*packet_size) - 1]);
 755                 rc = -ENOSYS;
 756                 goto out_free;
 757         }
 758         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
 759         /* TODO: Parametarize; we might actually want userspace to
 760          * decrypt the session key. */
 761         (*new_auth_tok)->session_key.flags &=
 762                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
 763         (*new_auth_tok)->session_key.flags &=
 764                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
 765         list_add(&auth_tok_list_item->list, auth_tok_list);
 766         goto out;
 767 out_free:
 768         (*new_auth_tok) = NULL;
 769         memset(auth_tok_list_item, 0,
 770                sizeof(struct ecryptfs_auth_tok_list_item));
 771         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 772                         auth_tok_list_item);
 773 out:
 774         if (rc)
 775                 (*packet_size) = 0;
 776         return rc;
 777 }
 778
 779 /**
 780  * parse_tag_11_packet
 781  * @data: The raw bytes of the packet
 782  * @contents: This function writes the data contents of the literal
 783  *            packet into this memory location
 784  * @max_contents_bytes: The maximum number of bytes that this function
 785  *                      is allowed to write into contents
 786  * @tag_11_contents_size: This function writes the size of the parsed
 787  *                        contents into this memory location; zero on
 788  *                        error
 789  * @packet_size: This function writes the size of the parsed packet
 790  *               into this memory location; zero on error
 791  * @max_packet_size: maximum number of bytes to parse
 792  *
 793  * Returns zero on success; non-zero on error.
 794  */
 795 static int
 796 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
 797                     size_t max_contents_bytes, size_t *tag_11_contents_size,
 798                     size_t *packet_size, size_t max_packet_size)
 799 {
 800         size_t body_size;
 801         size_t length_size;
 802         int rc = 0;
 803
 804         (*packet_size) = 0;
 805         (*tag_11_contents_size) = 0;
 806         /* This format is inspired by OpenPGP; see RFC 2440
 807          * packet tag 11
 808          *
 809          * Tag 11 identifier (1 byte)
 810          * Max Tag 11 packet size (max 3 bytes)
 811          * Binary format specifier (1 byte)
 812          * Filename length (1 byte)
 813          * Filename ("_CONSOLE") (8 bytes)
 814          * Modification date (4 bytes)
 815          * Literal data (arbitrary)
 816          *
 817          * We need at least 16 bytes of data for the packet to even be
 818          * valid.
 819          */
 820         if (max_packet_size < 16) {
 821                 printk(KERN_ERR "Maximum packet size too small\n");
 822                 rc = -EINVAL;
 823                 goto out;
 824         }
 825         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
 826                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
 827                 rc = -EINVAL;
 828                 goto out;
 829         }
 830         if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
 831                                       &length_size))) {
 832                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
 833                 goto out;
 834         }
 835         if (body_size < 14) {
 836                 printk(KERN_WARNING "Invalid body size ([%d])\n", body_size);
 837                 rc = -EINVAL;
 838                 goto out;
 839         }
 840         (*packet_size) += length_size;
 841         (*tag_11_contents_size) = (body_size - 14);
 842         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
 843                 printk(KERN_ERR "Packet size exceeds max\n");
 844                 rc = -EINVAL;
 845                 goto out;
 846         }
 847         if (data[(*packet_size)++] != 0x62) {
 848                 printk(KERN_WARNING "Unrecognizable packet\n");
 849                 rc = -EINVAL;
 850                 goto out;
 851         }
 852         if (data[(*packet_size)++] != 0x08) {
 853                 printk(KERN_WARNING "Unrecognizable packet\n");
 854                 rc = -EINVAL;
 855                 goto out;
 856         }
 857         (*packet_size) += 12; /* Ignore filename and modification date */
 858         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
 859         (*packet_size) += (*tag_11_contents_size);
 860 out:
 861         if (rc) {
 862                 (*packet_size) = 0;
 863                 (*tag_11_contents_size) = 0;
 864         }
 865         return rc;
 866 }
 867
 868 static int
 869 ecryptfs_find_global_auth_tok_for_sig(
 870         struct ecryptfs_global_auth_tok **global_auth_tok,
 871         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 872 {
 873         struct ecryptfs_global_auth_tok *walker;
 874         int rc = 0;
 875
 876         (*global_auth_tok) = NULL;
 877         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 878         list_for_each_entry(walker,
 879                             &mount_crypt_stat->global_auth_tok_list,
 880                             mount_crypt_stat_list) {
 881                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX) == 0) {
 882                         (*global_auth_tok) = walker;
 883                         goto out;
 884                 }
 885         }
 886         rc = -EINVAL;
 887 out:
 888         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 889         return rc;
 890 }
 891
 892 /**
 893  * ecryptfs_verify_version
 894  * @version: The version number to confirm
 895  *
 896  * Returns zero on good version; non-zero otherwise
 897  */
 898 static int ecryptfs_verify_version(u16 version)
 899 {
 900         int rc = 0;
 901         unsigned char major;
 902         unsigned char minor;
 903
 904         major = ((version >> 8) & 0xFF);
 905         minor = (version & 0xFF);
 906         if (major != ECRYPTFS_VERSION_MAJOR) {
 907                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 908                                 "Expected [%d]; got [%d]\n",
 909                                 ECRYPTFS_VERSION_MAJOR, major);
 910                 rc = -EINVAL;
 911                 goto out;
 912         }
 913         if (minor != ECRYPTFS_VERSION_MINOR) {
 914                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 915                                 "Expected [%d]; got [%d]\n",
 916                                 ECRYPTFS_VERSION_MINOR, minor);
 917                 rc = -EINVAL;
 918                 goto out;
 919         }
 920 out:
 921         return rc;
 922 }
 923
 924 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
 925                                       struct ecryptfs_auth_tok **auth_tok,
 926                                       char *sig)
 927 {
 928         int rc = 0;
 929
 930         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
 931         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
 932                 printk(KERN_ERR "Could not find key with description: [%s]\n",
 933                        sig);
 934                 process_request_key_err(PTR_ERR(*auth_tok_key));
 935                 rc = -EINVAL;
 936                 goto out;
 937         }
 938         (*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
 939         if (ecryptfs_verify_version((*auth_tok)->version)) {
 940                 printk(KERN_ERR
 941                        "Data structure version mismatch. "
 942                        "Userspace tools must match eCryptfs "
 943                        "kernel module with major version [%d] "
 944                        "and minor version [%d]\n",
 945                        ECRYPTFS_VERSION_MAJOR,
 946                        ECRYPTFS_VERSION_MINOR);
 947                 rc = -EINVAL;
 948                 goto out;
 949         }
 950         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
 951             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
 952                 printk(KERN_ERR "Invalid auth_tok structure "
 953                        "returned from key query\n");
 954                 rc = -EINVAL;
 955                 goto out;
 956         }
 957 out:
 958         return rc;
 959 }
 960
 961 /**
 962  * ecryptfs_find_auth_tok_for_sig
 963  * @auth_tok: Set to the matching auth_tok; NULL if not found
 964  * @crypt_stat: inode crypt_stat crypto context
 965  * @sig: Sig of auth_tok to find
 966  *
 967  * For now, this function simply looks at the registered auth_tok's
 968  * linked off the mount_crypt_stat, so all the auth_toks that can be
 969  * used must be registered at mount time. This function could
 970  * potentially try a lot harder to find auth_tok's (e.g., by calling
 971  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
 972  * that static registration of auth_tok's will no longer be necessary.
 973  *
 974  * Returns zero on no error; non-zero on error
 975  */
 976 static int
 977 ecryptfs_find_auth_tok_for_sig(
 978         struct ecryptfs_auth_tok **auth_tok,
 979         struct ecryptfs_crypt_stat *crypt_stat, char *sig)
 980 {
 981         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 982                 crypt_stat->mount_crypt_stat;
 983         struct ecryptfs_global_auth_tok *global_auth_tok;
 984         int rc = 0;
 985
 986         (*auth_tok) = NULL;
 987         if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
 988                                                   mount_crypt_stat, sig)) {
 989                 struct key *auth_tok_key;
 990
 991                 rc = ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key, auth_tok,
 992                                                        sig);
 993         } else
 994                 (*auth_tok) = global_auth_tok->global_auth_tok;
 995         return rc;
 996 }
 997
 998 /**
 999  * decrypt_passphrase_encrypted_session_key - Decrypt the session key
1000  * with the given auth_tok.
1001  *
1002  * Returns Zero on success; non-zero error otherwise.
1003  */
1004 static int
1005 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1006                                          struct ecryptfs_crypt_stat *crypt_stat)
1007 {
1008         struct scatterlist dst_sg;
1009         struct scatterlist src_sg;
1010         struct mutex *tfm_mutex = NULL;
1011         struct blkcipher_desc desc = {
1012                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1013         };
1014         int rc = 0;
1015
1016         if (unlikely(ecryptfs_verbosity > 0)) {
1017                 ecryptfs_printk(
1018                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1019                         auth_tok->token.password.session_key_encryption_key_bytes);
1020                 ecryptfs_dump_hex(
1021                         auth_tok->token.password.session_key_encryption_key,
1022                         auth_tok->token.password.session_key_encryption_key_bytes);
1023         }
1024         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1025                                                         crypt_stat->cipher);
1026         if (unlikely(rc)) {
1027                 printk(KERN_ERR "Internal error whilst attempting to get "
1028                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1029                        crypt_stat->cipher, rc);
1030                 goto out;
1031         }
1032         if ((rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1033                                       auth_tok->session_key.encrypted_key_size,
1034                                       &src_sg, 1)) != 1) {
1035                 printk(KERN_ERR "Internal error whilst attempting to convert "
1036                         "auth_tok->session_key.encrypted_key to scatterlist; "
1037                         "expected rc = 1; got rc = [%d]. "
1038                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1039                         auth_tok->session_key.encrypted_key_size);
1040                 goto out;
1041         }
1042         auth_tok->session_key.decrypted_key_size =
1043                 auth_tok->session_key.encrypted_key_size;
1044         if ((rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1045                                       auth_tok->session_key.decrypted_key_size,
1046                                       &dst_sg, 1)) != 1) {
1047                 printk(KERN_ERR "Internal error whilst attempting to convert "
1048                         "auth_tok->session_key.decrypted_key to scatterlist; "
1049                         "expected rc = 1; got rc = [%d]\n", rc);
1050                 goto out;
1051         }
1052         mutex_lock(tfm_mutex);
1053         rc = crypto_blkcipher_setkey(
1054                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1055                 crypt_stat->key_size);
1056         if (unlikely(rc < 0)) {
1057                 mutex_unlock(tfm_mutex);
1058                 printk(KERN_ERR "Error setting key for crypto context\n");
1059                 rc = -EINVAL;
1060                 goto out;
1061         }
1062         rc = crypto_blkcipher_decrypt(&desc, &dst_sg, &src_sg,
1063                                       auth_tok->session_key.encrypted_key_size);
1064         mutex_unlock(tfm_mutex);
1065         if (unlikely(rc)) {
1066                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1067                 goto out;
1068         }
1069         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1070         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1071                auth_tok->session_key.decrypted_key_size);
1072         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1073         if (unlikely(ecryptfs_verbosity > 0)) {
1074                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
1075                                 crypt_stat->key_size);
1076                 ecryptfs_dump_hex(crypt_stat->key,
1077                                   crypt_stat->key_size);
1078         }
1079 out:
1080         return rc;
1081 }
1082
1083 int ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1084 {
1085         int rc = 0;
1086
1087         (*sig) = NULL;
1088         switch (auth_tok->token_type) {
1089         case ECRYPTFS_PASSWORD:
1090                 (*sig) = auth_tok->token.password.signature;
1091                 break;
1092         case ECRYPTFS_PRIVATE_KEY:
1093                 (*sig) = auth_tok->token.private_key.signature;
1094                 break;
1095         default:
1096                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1097                        auth_tok->token_type);
1098                 rc = -EINVAL;
1099         }
1100         return rc;
1101 }
1102
1103 /**
1104  * ecryptfs_parse_packet_set
1105  * @dest: The header page in memory
1106  * @version: Version of file format, to guide parsing behavior
1107  *
1108  * Get crypt_stat to have the file's session key if the requisite key
1109  * is available to decrypt the session key.
1110  *
1111  * Returns Zero if a valid authentication token was retrieved and
1112  * processed; negative value for file not encrypted or for error
1113  * conditions.
1114  */
1115 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1116                               unsigned char *src,
1117                               struct dentry *ecryptfs_dentry)
1118 {
1119         size_t i = 0;
1120         size_t found_auth_tok;
1121         size_t next_packet_is_auth_tok_packet;
1122         struct list_head auth_tok_list;
1123         struct ecryptfs_auth_tok *matching_auth_tok = NULL;
1124         struct ecryptfs_auth_tok *candidate_auth_tok = NULL;
1125         char *candidate_auth_tok_sig;
1126         size_t packet_size;
1127         struct ecryptfs_auth_tok *new_auth_tok;
1128         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1129         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1130         size_t tag_11_contents_size;
1131         size_t tag_11_packet_size;
1132         int rc = 0;
1133
1134         INIT_LIST_HEAD(&auth_tok_list);
1135         /* Parse the header to find as many packets as we can; these will be
1136          * added the our &auth_tok_list */
1137         next_packet_is_auth_tok_packet = 1;
1138         while (next_packet_is_auth_tok_packet) {
1139                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1140
1141                 switch (src[i]) {
1142                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1143                         rc = parse_tag_3_packet(crypt_stat,
1144                                                 (unsigned char *)&src[i],
1145                                                 &auth_tok_list, &new_auth_tok,
1146                                                 &packet_size, max_packet_size);
1147                         if (rc) {
1148                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1149                                                 "tag 3 packet\n");
1150                                 rc = -EIO;
1151                                 goto out_wipe_list;
1152                         }
1153                         i += packet_size;
1154                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1155                                                  sig_tmp_space,
1156                                                  ECRYPTFS_SIG_SIZE,
1157                                                  &tag_11_contents_size,
1158                                                  &tag_11_packet_size,
1159                                                  max_packet_size);
1160                         if (rc) {
1161                                 ecryptfs_printk(KERN_ERR, "No valid "
1162                                                 "(ecryptfs-specific) literal "
1163                                                 "packet containing "
1164                                                 "authentication token "
1165                                                 "signature found after "
1166                                                 "tag 3 packet\n");
1167                                 rc = -EIO;
1168                                 goto out_wipe_list;
1169                         }
1170                         i += tag_11_packet_size;
1171                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1172                                 ecryptfs_printk(KERN_ERR, "Expected "
1173                                                 "signature of size [%d]; "
1174                                                 "read size [%d]\n",
1175                                                 ECRYPTFS_SIG_SIZE,
1176                                                 tag_11_contents_size);
1177                                 rc = -EIO;
1178                                 goto out_wipe_list;
1179                         }
1180                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1181                                         sig_tmp_space, tag_11_contents_size);
1182                         new_auth_tok->token.password.signature[
1183                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1184                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1185                         break;
1186                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1187                         rc = parse_tag_1_packet(crypt_stat,
1188                                                 (unsigned char *)&src[i],
1189                                                 &auth_tok_list, &new_auth_tok,
1190                                                 &packet_size, max_packet_size);
1191                         if (rc) {
1192                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1193                                                 "tag 1 packet\n");
1194                                 rc = -EIO;
1195                                 goto out_wipe_list;
1196                         }
1197                         i += packet_size;
1198                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1199                         break;
1200                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1201                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1202                                         "(Tag 11 not allowed by itself)\n");
1203                         rc = -EIO;
1204                         goto out_wipe_list;
1205                         break;
1206                 default:
1207                         ecryptfs_printk(KERN_DEBUG, "No packet at offset "
1208                                         "[%d] of the file header; hex value of "
1209                                         "character is [0x%.2x]\n", i, src[i]);
1210                         next_packet_is_auth_tok_packet = 0;
1211                 }
1212         }
1213         if (list_empty(&auth_tok_list)) {
1214                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1215                        "eCryptfs file; this is not supported in this version "
1216                        "of the eCryptfs kernel module\n");
1217                 rc = -EINVAL;
1218                 goto out;
1219         }
1220         /* auth_tok_list contains the set of authentication tokens
1221          * parsed from the metadata. We need to find a matching
1222          * authentication token that has the secret component(s)
1223          * necessary to decrypt the EFEK in the auth_tok parsed from
1224          * the metadata. There may be several potential matches, but
1225          * just one will be sufficient to decrypt to get the FEK. */
1226 find_next_matching_auth_tok:
1227         found_auth_tok = 0;
1228         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1229                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1230                 if (unlikely(ecryptfs_verbosity > 0)) {
1231                         ecryptfs_printk(KERN_DEBUG,
1232                                         "Considering cadidate auth tok:\n");
1233                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1234                 }
1235                 if ((rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1236                                                     candidate_auth_tok))) {
1237                         printk(KERN_ERR
1238                                "Unrecognized candidate auth tok type: [%d]\n",
1239                                candidate_auth_tok->token_type);
1240                         rc = -EINVAL;
1241                         goto out_wipe_list;
1242                 }
1243                 if ((rc = ecryptfs_find_auth_tok_for_sig(
1244                              &matching_auth_tok, crypt_stat,
1245                              candidate_auth_tok_sig)))
1246                         rc = 0;
1247                 if (matching_auth_tok) {
1248                         found_auth_tok = 1;
1249                         goto found_matching_auth_tok;
1250                 }
1251         }
1252         if (!found_auth_tok) {
1253                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1254                                 "authentication token\n");
1255                 rc = -EIO;
1256                 goto out_wipe_list;
1257         }
1258 found_matching_auth_tok:
1259         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1260                 memcpy(&(candidate_auth_tok->token.private_key),
1261                        &(matching_auth_tok->token.private_key),
1262                        sizeof(struct ecryptfs_private_key));
1263                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1264                                                        crypt_stat);
1265         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1266                 memcpy(&(candidate_auth_tok->token.password),
1267                        &(matching_auth_tok->token.password),
1268                        sizeof(struct ecryptfs_password));
1269                 rc = decrypt_passphrase_encrypted_session_key(
1270                         candidate_auth_tok, crypt_stat);
1271         }
1272         if (rc) {
1273                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1274
1275                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1276                                 "session key for authentication token with sig "
1277                                 "[%.*s]; rc = [%d]. Removing auth tok "
1278                                 "candidate from the list and searching for "
1279                                 "the next match.\n", candidate_auth_tok_sig,
1280                                 ECRYPTFS_SIG_SIZE_HEX, rc);
1281                 list_for_each_entry_safe(auth_tok_list_item,
1282                                          auth_tok_list_item_tmp,
1283                                          &auth_tok_list, list) {
1284                         if (candidate_auth_tok
1285                             == &auth_tok_list_item->auth_tok) {
1286                                 list_del(&auth_tok_list_item->list);
1287                                 kmem_cache_free(
1288                                         ecryptfs_auth_tok_list_item_cache,
1289                                         auth_tok_list_item);
1290                                 goto find_next_matching_auth_tok;
1291                         }
1292                 }
1293                 BUG();
1294         }
1295         rc = ecryptfs_compute_root_iv(crypt_stat);
1296         if (rc) {
1297                 ecryptfs_printk(KERN_ERR, "Error computing "
1298                                 "the root IV\n");
1299                 goto out_wipe_list;
1300         }
1301         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1302         if (rc) {
1303                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1304                                 "context for cipher [%s]; rc = [%d]\n",
1305                                 crypt_stat->cipher, rc);
1306         }
1307 out_wipe_list:
1308         wipe_auth_tok_list(&auth_tok_list);
1309 out:
1310         return rc;
1311 }
1312
1313 static int
1314 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1315                         struct ecryptfs_crypt_stat *crypt_stat,
1316                         struct ecryptfs_key_record *key_rec)
1317 {
1318         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1319         char *netlink_payload;
1320         size_t netlink_payload_length;
1321         struct ecryptfs_message *msg;
1322         int rc;
1323
1324         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1325                                  ecryptfs_code_for_cipher_string(crypt_stat),
1326                                  crypt_stat, &netlink_payload,
1327                                  &netlink_payload_length);
1328         if (rc) {
1329                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1330                 goto out;
1331         }
1332         rc = ecryptfs_send_message(ecryptfs_transport, netlink_payload,
1333                                    netlink_payload_length, &msg_ctx);
1334         if (rc) {
1335                 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
1336                 goto out;
1337         }
1338         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1339         if (rc) {
1340                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1341                                 "from the user space daemon\n");
1342                 rc = -EIO;
1343                 goto out;
1344         }
1345         rc = parse_tag_67_packet(key_rec, msg);
1346         if (rc)
1347                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1348         kfree(msg);
1349 out:
1350         if (netlink_payload)
1351                 kfree(netlink_payload);
1352         return rc;
1353 }
1354 /**
1355  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1356  * @dest: Buffer into which to write the packet
1357  * @max: Maximum number of bytes that can be writtn
1358  * @packet_size: This function will write the number of bytes that end
1359  *               up constituting the packet; set to zero on error
1360  *
1361  * Returns zero on success; non-zero on error.
1362  */
1363 static int
1364 write_tag_1_packet(char *dest, size_t *remaining_bytes,
1365                    struct ecryptfs_auth_tok *auth_tok,
1366                    struct ecryptfs_crypt_stat *crypt_stat,
1367                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1368 {
1369         size_t i;
1370         size_t encrypted_session_key_valid = 0;
1371         size_t packet_size_length;
1372         size_t max_packet_size;
1373         int rc = 0;
1374
1375         (*packet_size) = 0;
1376         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
1377                           ECRYPTFS_SIG_SIZE);
1378         encrypted_session_key_valid = 0;
1379         for (i = 0; i < crypt_stat->key_size; i++)
1380                 encrypted_session_key_valid |=
1381                         auth_tok->session_key.encrypted_key[i];
1382         if (encrypted_session_key_valid) {
1383                 memcpy(key_rec->enc_key,
1384                        auth_tok->session_key.encrypted_key,
1385                        auth_tok->session_key.encrypted_key_size);
1386                 goto encrypted_session_key_set;
1387         }
1388         if (auth_tok->session_key.encrypted_key_size == 0)
1389                 auth_tok->session_key.encrypted_key_size =
1390                         auth_tok->token.private_key.key_size;
1391         rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
1392         if (rc) {
1393                 ecryptfs_printk(KERN_ERR, "Failed to encrypt session key "
1394                                 "via a pki");
1395                 goto out;
1396         }
1397         if (ecryptfs_verbosity > 0) {
1398                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
1399                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
1400         }
1401 encrypted_session_key_set:
1402         /* This format is inspired by OpenPGP; see RFC 2440
1403          * packet tag 1 */
1404         max_packet_size = (1                         /* Tag 1 identifier */
1405                            + 3                       /* Max Tag 1 packet size */
1406                            + 1                       /* Version */
1407                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
1408                            + 1                       /* Cipher identifier */
1409                            + key_rec->enc_key_size); /* Encrypted key size */
1410         if (max_packet_size > (*remaining_bytes)) {
1411                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1412                        "need up to [%d] bytes, but there are only [%d] "
1413                        "available\n", max_packet_size, (*remaining_bytes));
1414                 rc = -EINVAL;
1415                 goto out;
1416         }
1417         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
1418         rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
1419                                  &packet_size_length);
1420         if (rc) {
1421                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
1422                                 "header; cannot generate packet length\n");
1423                 goto out;
1424         }
1425         (*packet_size) += packet_size_length;
1426         dest[(*packet_size)++] = 0x03; /* version 3 */
1427         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
1428         (*packet_size) += ECRYPTFS_SIG_SIZE;
1429         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
1430         memcpy(&dest[(*packet_size)], key_rec->enc_key,
1431                key_rec->enc_key_size);
1432         (*packet_size) += key_rec->enc_key_size;
1433 out:
1434         if (rc)
1435                 (*packet_size) = 0;
1436         else
1437                 (*remaining_bytes) -= (*packet_size);
1438         return rc;
1439 }
1440
1441 /**
1442  * write_tag_11_packet
1443  * @dest: Target into which Tag 11 packet is to be written
1444  * @max: Maximum packet length
1445  * @contents: Byte array of contents to copy in
1446  * @contents_length: Number of bytes in contents
1447  * @packet_length: Length of the Tag 11 packet written; zero on error
1448  *
1449  * Returns zero on success; non-zero on error.
1450  */
1451 static int
1452 write_tag_11_packet(char *dest, int *remaining_bytes, char *contents,
1453                     size_t contents_length, size_t *packet_length)
1454 {
1455         size_t packet_size_length;
1456         size_t max_packet_size;
1457         int rc = 0;
1458
1459         (*packet_length) = 0;
1460         /* This format is inspired by OpenPGP; see RFC 2440
1461          * packet tag 11 */
1462         max_packet_size = (1                   /* Tag 11 identifier */
1463                            + 3                 /* Max Tag 11 packet size */
1464                            + 1                 /* Binary format specifier */
1465                            + 1                 /* Filename length */
1466                            + 8                 /* Filename ("_CONSOLE") */
1467                            + 4                 /* Modification date */
1468                            + contents_length); /* Literal data */
1469         if (max_packet_size > (*remaining_bytes)) {
1470                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1471                        "need up to [%d] bytes, but there are only [%d] "
1472                        "available\n", max_packet_size, (*remaining_bytes));
1473                 rc = -EINVAL;
1474                 goto out;
1475         }
1476         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
1477         rc = write_packet_length(&dest[(*packet_length)],
1478                                  (max_packet_size - 4), &packet_size_length);
1479         if (rc) {
1480                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
1481                        "generate packet length. rc = [%d]\n", rc);
1482                 goto out;
1483         }
1484         (*packet_length) += packet_size_length;
1485         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
1486         dest[(*packet_length)++] = 8;
1487         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
1488         (*packet_length) += 8;
1489         memset(&dest[(*packet_length)], 0x00, 4);
1490         (*packet_length) += 4;
1491         memcpy(&dest[(*packet_length)], contents, contents_length);
1492         (*packet_length) += contents_length;
1493  out:
1494         if (rc)
1495                 (*packet_length) = 0;
1496         else
1497                 (*remaining_bytes) -= (*packet_length);
1498         return rc;
1499 }
1500
1501 /**
1502  * write_tag_3_packet
1503  * @dest: Buffer into which to write the packet
1504  * @max: Maximum number of bytes that can be written
1505  * @auth_tok: Authentication token
1506  * @crypt_stat: The cryptographic context
1507  * @key_rec: encrypted key
1508  * @packet_size: This function will write the number of bytes that end
1509  *               up constituting the packet; set to zero on error
1510  *
1511  * Returns zero on success; non-zero on error.
1512  */
1513 static int
1514 write_tag_3_packet(char *dest, size_t *remaining_bytes,
1515                    struct ecryptfs_auth_tok *auth_tok,
1516                    struct ecryptfs_crypt_stat *crypt_stat,
1517                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1518 {
1519         size_t i;
1520         size_t encrypted_session_key_valid = 0;
1521         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
1522         struct scatterlist dst_sg;
1523         struct scatterlist src_sg;
1524         struct mutex *tfm_mutex = NULL;
1525         size_t cipher_code;
1526         size_t packet_size_length;
1527         size_t max_packet_size;
1528         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1529                 crypt_stat->mount_crypt_stat;
1530         struct blkcipher_desc desc = {
1531                 .tfm = NULL,
1532                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1533         };
1534         int rc = 0;
1535
1536         (*packet_size) = 0;
1537         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
1538                           ECRYPTFS_SIG_SIZE);
1539         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1540                                                         crypt_stat->cipher);
1541         if (unlikely(rc)) {
1542                 printk(KERN_ERR "Internal error whilst attempting to get "
1543                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1544                        crypt_stat->cipher, rc);
1545                 goto out;
1546         }
1547         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
1548                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
1549
1550                 printk(KERN_WARNING "No key size specified at mount; "
1551                        "defaulting to [%d]\n", alg->max_keysize);
1552                 mount_crypt_stat->global_default_cipher_key_size =
1553                         alg->max_keysize;
1554         }
1555         if (crypt_stat->key_size == 0)
1556                 crypt_stat->key_size =
1557                         mount_crypt_stat->global_default_cipher_key_size;
1558         if (auth_tok->session_key.encrypted_key_size == 0)
1559                 auth_tok->session_key.encrypted_key_size =
1560                         crypt_stat->key_size;
1561         if (crypt_stat->key_size == 24
1562             && strcmp("aes", crypt_stat->cipher) == 0) {
1563                 memset((crypt_stat->key + 24), 0, 8);
1564                 auth_tok->session_key.encrypted_key_size = 32;
1565         } else
1566                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
1567         key_rec->enc_key_size =
1568                 auth_tok->session_key.encrypted_key_size;
1569         encrypted_session_key_valid = 0;
1570         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
1571                 encrypted_session_key_valid |=
1572                         auth_tok->session_key.encrypted_key[i];
1573         if (encrypted_session_key_valid) {
1574                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
1575                                 "using auth_tok->session_key.encrypted_key, "
1576                                 "where key_rec->enc_key_size = [%d]\n",
1577                                 key_rec->enc_key_size);
1578                 memcpy(key_rec->enc_key,
1579                        auth_tok->session_key.encrypted_key,
1580                        key_rec->enc_key_size);
1581                 goto encrypted_session_key_set;
1582         }
1583         if (auth_tok->token.password.flags &
1584             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
1585                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
1586                                 "session key encryption key of size [%d]\n",
1587                                 auth_tok->token.password.
1588                                 session_key_encryption_key_bytes);
1589                 memcpy(session_key_encryption_key,
1590                        auth_tok->token.password.session_key_encryption_key,
1591                        crypt_stat->key_size);
1592                 ecryptfs_printk(KERN_DEBUG,
1593                                 "Cached session key " "encryption key: \n");
1594                 if (ecryptfs_verbosity > 0)
1595                         ecryptfs_dump_hex(session_key_encryption_key, 16);
1596         }
1597         if (unlikely(ecryptfs_verbosity > 0)) {
1598                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
1599                 ecryptfs_dump_hex(session_key_encryption_key, 16);
1600         }
1601         if ((rc = virt_to_scatterlist(crypt_stat->key,
1602                                       key_rec->enc_key_size, &src_sg, 1))
1603             != 1) {
1604                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1605                                 "for crypt_stat session key; expected rc = 1; "
1606                                 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1607                                 rc, key_rec->enc_key_size);
1608                 rc = -ENOMEM;
1609                 goto out;
1610         }
1611         if ((rc = virt_to_scatterlist(key_rec->enc_key,
1612                                       key_rec->enc_key_size, &dst_sg, 1))
1613             != 1) {
1614                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1615                                 "for crypt_stat encrypted session key; "
1616                                 "expected rc = 1; got rc = [%d]. "
1617                                 "key_rec->enc_key_size = [%d]\n", rc,
1618                                 key_rec->enc_key_size);
1619                 rc = -ENOMEM;
1620                 goto out;
1621         }
1622         mutex_lock(tfm_mutex);
1623         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
1624                                      crypt_stat->key_size);
1625         if (rc < 0) {
1626                 mutex_unlock(tfm_mutex);
1627                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
1628                                 "context; rc = [%d]\n", rc);
1629                 goto out;
1630         }
1631         rc = 0;
1632         ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
1633                         crypt_stat->key_size);
1634         rc = crypto_blkcipher_encrypt(&desc, &dst_sg, &src_sg,
1635                                       (*key_rec).enc_key_size);
1636         mutex_unlock(tfm_mutex);
1637         if (rc) {
1638                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
1639                 goto out;
1640         }
1641         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
1642         if (ecryptfs_verbosity > 0) {
1643                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
1644                                 key_rec->enc_key_size);
1645                 ecryptfs_dump_hex(key_rec->enc_key,
1646                                   key_rec->enc_key_size);
1647         }
1648 encrypted_session_key_set:
1649         /* This format is inspired by OpenPGP; see RFC 2440
1650          * packet tag 3 */
1651         max_packet_size = (1                         /* Tag 3 identifier */
1652                            + 3                       /* Max Tag 3 packet size */
1653                            + 1                       /* Version */
1654                            + 1                       /* Cipher code */
1655                            + 1                       /* S2K specifier */
1656                            + 1                       /* Hash identifier */
1657                            + ECRYPTFS_SALT_SIZE      /* Salt */
1658                            + 1                       /* Hash iterations */
1659                            + key_rec->enc_key_size); /* Encrypted key size */
1660         if (max_packet_size > (*remaining_bytes)) {
1661                 printk(KERN_ERR "Packet too large; need up to [%d] bytes, but "
1662                        "there are only [%d] available\n", max_packet_size,
1663                        (*remaining_bytes));
1664                 rc = -EINVAL;
1665                 goto out;
1666         }
1667         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
1668         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1669          * to get the number of octets in the actual Tag 3 packet */
1670         rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
1671                                  &packet_size_length);
1672         if (rc) {
1673                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
1674                        "generate packet length. rc = [%d]\n", rc);
1675                 goto out;
1676         }
1677         (*packet_size) += packet_size_length;
1678         dest[(*packet_size)++] = 0x04; /* version 4 */
1679         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1680          * specified with strings */
1681         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat);
1682         if (cipher_code == 0) {
1683                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
1684                                 "cipher [%s]\n", crypt_stat->cipher);
1685                 rc = -EINVAL;
1686                 goto out;
1687         }
1688         dest[(*packet_size)++] = cipher_code;
1689         dest[(*packet_size)++] = 0x03;  /* S2K */
1690         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
1691         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
1692                ECRYPTFS_SALT_SIZE);
1693         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
1694         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
1695         memcpy(&dest[(*packet_size)], key_rec->enc_key,
1696                key_rec->enc_key_size);
1697         (*packet_size) += key_rec->enc_key_size;
1698 out:
1699         if (rc)
1700                 (*packet_size) = 0;
1701         else
1702                 (*remaining_bytes) -= (*packet_size);
1703         return rc;
1704 }
1705
1706 struct kmem_cache *ecryptfs_key_record_cache;
1707
1708 /**
1709  * ecryptfs_generate_key_packet_set
1710  * @dest: Virtual address from which to write the key record set
1711  * @crypt_stat: The cryptographic context from which the
1712  *              authentication tokens will be retrieved
1713  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1714  *                   for the global parameters
1715  * @len: The amount written
1716  * @max: The maximum amount of data allowed to be written
1717  *
1718  * Generates a key packet set and writes it to the virtual address
1719  * passed in.
1720  *
1721  * Returns zero on success; non-zero on error.
1722  */
1723 int
1724 ecryptfs_generate_key_packet_set(char *dest_base,
1725                                  struct ecryptfs_crypt_stat *crypt_stat,
1726                                  struct dentry *ecryptfs_dentry, size_t *len,
1727                                  size_t max)
1728 {
1729         struct ecryptfs_auth_tok *auth_tok;
1730         struct ecryptfs_global_auth_tok *global_auth_tok;
1731         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1732                 &ecryptfs_superblock_to_private(
1733                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
1734         size_t written;
1735         struct ecryptfs_key_record *key_rec;
1736         struct ecryptfs_key_sig *key_sig;
1737         int rc = 0;
1738
1739         (*len) = 0;
1740         mutex_lock(&crypt_stat->keysig_list_mutex);
1741         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
1742         if (!key_rec) {
1743                 rc = -ENOMEM;
1744                 goto out;
1745         }
1746         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
1747                             crypt_stat_list) {
1748                 memset(key_rec, 0, sizeof(*key_rec));
1749                 rc = ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
1750                                                            mount_crypt_stat,
1751                                                            key_sig->keysig);
1752                 if (rc) {
1753                         printk(KERN_ERR "Error attempting to get the global "
1754                                "auth_tok; rc = [%d]\n", rc);
1755                         goto out_free;
1756                 }
1757                 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
1758                         printk(KERN_WARNING
1759                                "Skipping invalid auth tok with sig = [%s]\n",
1760                                global_auth_tok->sig);
1761                         continue;
1762                 }
1763                 auth_tok = global_auth_tok->global_auth_tok;
1764                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
1765                         rc = write_tag_3_packet((dest_base + (*len)),
1766                                                 &max, auth_tok,
1767                                                 crypt_stat, key_rec,
1768                                                 &written);
1769                         if (rc) {
1770                                 ecryptfs_printk(KERN_WARNING, "Error "
1771                                                 "writing tag 3 packet\n");
1772                                 goto out_free;
1773                         }
1774                         (*len) += written;
1775                         /* Write auth tok signature packet */
1776                         rc = write_tag_11_packet((dest_base + (*len)), &max,
1777                                                  key_rec->sig,
1778                                                  ECRYPTFS_SIG_SIZE, &written);
1779                         if (rc) {
1780                                 ecryptfs_printk(KERN_ERR, "Error writing "
1781                                                 "auth tok signature packet\n");
1782                                 goto out_free;
1783                         }
1784                         (*len) += written;
1785                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1786                         rc = write_tag_1_packet(dest_base + (*len),
1787                                                 &max, auth_tok,
1788                                                 crypt_stat, key_rec, &written);
1789                         if (rc) {
1790                                 ecryptfs_printk(KERN_WARNING, "Error "
1791                                                 "writing tag 1 packet\n");
1792                                 goto out_free;
1793                         }
1794                         (*len) += written;
1795                 } else {
1796                         ecryptfs_printk(KERN_WARNING, "Unsupported "
1797                                         "authentication token type\n");
1798                         rc = -EINVAL;
1799                         goto out_free;
1800                 }
1801         }
1802         if (likely(max > 0)) {
1803                 dest_base[(*len)] = 0x00;
1804         } else {
1805                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
1806                 rc = -EIO;
1807         }
1808 out_free:
1809         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
1810 out:
1811         if (rc)
1812                 (*len) = 0;
1813         mutex_unlock(&crypt_stat->keysig_list_mutex);
1814         return rc;
1815 }
1816
1817 struct kmem_cache *ecryptfs_key_sig_cache;
1818
1819 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
1820 {
1821         struct ecryptfs_key_sig *new_key_sig;
1822         int rc = 0;
1823
1824         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
1825         if (!new_key_sig) {
1826                 rc = -ENOMEM;
1827                 printk(KERN_ERR
1828                        "Error allocating from ecryptfs_key_sig_cache\n");
1829                 goto out;
1830         }
1831         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
1832         mutex_lock(&crypt_stat->keysig_list_mutex);
1833         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
1834         mutex_unlock(&crypt_stat->keysig_list_mutex);
1835 out:
1836         return rc;
1837 }
1838
1839 struct kmem_cache *ecryptfs_global_auth_tok_cache;
1840
1841 int
1842 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1843                              char *sig)
1844 {
1845         struct ecryptfs_global_auth_tok *new_auth_tok;
1846         int rc = 0;
1847
1848         new_auth_tok = kmem_cache_alloc(ecryptfs_global_auth_tok_cache,
1849                                         GFP_KERNEL);
1850         if (!new_auth_tok) {
1851                 rc = -ENOMEM;
1852                 printk(KERN_ERR "Error allocating from "
1853                        "ecryptfs_global_auth_tok_cache\n");
1854                 goto out;
1855         }
1856         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
1857         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
1858         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
1859         list_add(&new_auth_tok->mount_crypt_stat_list,
1860                  &mount_crypt_stat->global_auth_tok_list);
1861         mount_crypt_stat->num_global_auth_toks++;
1862         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
1863 out:
1864         return rc;
1865 }
1866