err.no Git - linux-2.6/blob - 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 "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 static 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; non-zero on error
  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 length. Must
 110  *        have at least 5 bytes allocated.
 111  * @size: The length to write.
 112  * @packet_size_length: The number of bytes used to encode the packet
 113  *                      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 static int
 400 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
 401 {
 402         int rc = 0;
 403
 404         (*sig) = NULL;
 405         switch (auth_tok->token_type) {
 406         case ECRYPTFS_PASSWORD:
 407                 (*sig) = auth_tok->token.password.signature;
 408                 break;
 409         case ECRYPTFS_PRIVATE_KEY:
 410                 (*sig) = auth_tok->token.private_key.signature;
 411                 break;
 412         default:
 413                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
 414                        auth_tok->token_type);
 415                 rc = -EINVAL;
 416         }
 417         return rc;
 418 }
 419
 420 /**
 421  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
 422  * @auth_tok: The key authentication token used to decrypt the session key
 423  * @crypt_stat: The cryptographic context
 424  *
 425  * Returns zero on success; non-zero error otherwise.
 426  */
 427 static int
 428 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
 429                                   struct ecryptfs_crypt_stat *crypt_stat)
 430 {
 431         u16 cipher_code = 0;
 432         struct ecryptfs_msg_ctx *msg_ctx;
 433         struct ecryptfs_message *msg = NULL;
 434         char *auth_tok_sig;
 435         char *netlink_message;
 436         size_t netlink_message_length;
 437         int rc;
 438
 439         if ((rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok))) {
 440                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
 441                        auth_tok->token_type);
 442                 goto out;
 443         }
 444         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
 445                                  &netlink_message, &netlink_message_length);
 446         if (rc) {
 447                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet");
 448                 goto out;
 449         }
 450         rc = ecryptfs_send_message(ecryptfs_transport, netlink_message,
 451                                    netlink_message_length, &msg_ctx);
 452         if (rc) {
 453                 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
 454                 goto out;
 455         }
 456         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
 457         if (rc) {
 458                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
 459                                 "from the user space daemon\n");
 460                 rc = -EIO;
 461                 goto out;
 462         }
 463         rc = parse_tag_65_packet(&(auth_tok->session_key),
 464                                  &cipher_code, msg);
 465         if (rc) {
 466                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
 467                        rc);
 468                 goto out;
 469         }
 470         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 471         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
 472                auth_tok->session_key.decrypted_key_size);
 473         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
 474         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
 475         if (rc) {
 476                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
 477                                 cipher_code)
 478                 goto out;
 479         }
 480         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
 481         if (ecryptfs_verbosity > 0) {
 482                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
 483                 ecryptfs_dump_hex(crypt_stat->key,
 484                                   crypt_stat->key_size);
 485         }
 486 out:
 487         if (msg)
 488                 kfree(msg);
 489         return rc;
 490 }
 491
 492 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
 493 {
 494         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 495         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
 496
 497         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
 498                                  auth_tok_list_head, list) {
 499                 list_del(&auth_tok_list_item->list);
 500                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 501                                 auth_tok_list_item);
 502         }
 503 }
 504
 505 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
 506
 507 /**
 508  * parse_tag_1_packet
 509  * @crypt_stat: The cryptographic context to modify based on packet contents
 510  * @data: The raw bytes of the packet.
 511  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
 512  *                 a new authentication token will be placed at the
 513  *                 end of this list for this packet.
 514  * @new_auth_tok: Pointer to a pointer to memory that this function
 515  *                allocates; sets the memory address of the pointer to
 516  *                NULL on error. This object is added to the
 517  *                auth_tok_list.
 518  * @packet_size: This function writes the size of the parsed packet
 519  *               into this memory location; zero on error.
 520  * @max_packet_size: The maximum allowable packet size
 521  *
 522  * Returns zero on success; non-zero on error.
 523  */
 524 static int
 525 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
 526                    unsigned char *data, struct list_head *auth_tok_list,
 527                    struct ecryptfs_auth_tok **new_auth_tok,
 528                    size_t *packet_size, size_t max_packet_size)
 529 {
 530         size_t body_size;
 531         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 532         size_t length_size;
 533         int rc = 0;
 534
 535         (*packet_size) = 0;
 536         (*new_auth_tok) = NULL;
 537         /**
 538          * This format is inspired by OpenPGP; see RFC 2440
 539          * packet tag 1
 540          *
 541          * Tag 1 identifier (1 byte)
 542          * Max Tag 1 packet size (max 3 bytes)
 543          * Version (1 byte)
 544          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
 545          * Cipher identifier (1 byte)
 546          * Encrypted key size (arbitrary)
 547          *
 548          * 12 bytes minimum packet size
 549          */
 550         if (unlikely(max_packet_size < 12)) {
 551                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
 552                 rc = -EINVAL;
 553                 goto out;
 554         }
 555         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
 556                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
 557                        ECRYPTFS_TAG_1_PACKET_TYPE);
 558                 rc = -EINVAL;
 559                 goto out;
 560         }
 561         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
 562          * at end of function upon failure */
 563         auth_tok_list_item =
 564                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
 565                                   GFP_KERNEL);
 566         if (!auth_tok_list_item) {
 567                 printk(KERN_ERR "Unable to allocate memory\n");
 568                 rc = -ENOMEM;
 569                 goto out;
 570         }
 571         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
 572         if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
 573                                       &length_size))) {
 574                 printk(KERN_WARNING "Error parsing packet length; "
 575                        "rc = [%d]\n", rc);
 576                 goto out_free;
 577         }
 578         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
 579                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
 580                 rc = -EINVAL;
 581                 goto out_free;
 582         }
 583         (*packet_size) += length_size;
 584         if (unlikely((*packet_size) + body_size > max_packet_size)) {
 585                 printk(KERN_WARNING "Packet size exceeds max\n");
 586                 rc = -EINVAL;
 587                 goto out_free;
 588         }
 589         if (unlikely(data[(*packet_size)++] != 0x03)) {
 590                 printk(KERN_WARNING "Unknown version number [%d]\n",
 591                        data[(*packet_size) - 1]);
 592                 rc = -EINVAL;
 593                 goto out_free;
 594         }
 595         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
 596                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
 597         *packet_size += ECRYPTFS_SIG_SIZE;
 598         /* This byte is skipped because the kernel does not need to
 599          * know which public key encryption algorithm was used */
 600         (*packet_size)++;
 601         (*new_auth_tok)->session_key.encrypted_key_size =
 602                 body_size - (ECRYPTFS_SIG_SIZE + 2);
 603         if ((*new_auth_tok)->session_key.encrypted_key_size
 604             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 605                 printk(KERN_WARNING "Tag 1 packet contains key larger "
 606                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
 607                 rc = -EINVAL;
 608                 goto out;
 609         }
 610         memcpy((*new_auth_tok)->session_key.encrypted_key,
 611                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
 612         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
 613         (*new_auth_tok)->session_key.flags &=
 614                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 615         (*new_auth_tok)->session_key.flags |=
 616                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
 617         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
 618         (*new_auth_tok)->flags = 0;
 619         (*new_auth_tok)->session_key.flags &=
 620                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
 621         (*new_auth_tok)->session_key.flags &=
 622                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
 623         list_add(&auth_tok_list_item->list, auth_tok_list);
 624         goto out;
 625 out_free:
 626         (*new_auth_tok) = NULL;
 627         memset(auth_tok_list_item, 0,
 628                sizeof(struct ecryptfs_auth_tok_list_item));
 629         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 630                         auth_tok_list_item);
 631 out:
 632         if (rc)
 633                 (*packet_size) = 0;
 634         return rc;
 635 }
 636
 637 /**
 638  * parse_tag_3_packet
 639  * @crypt_stat: The cryptographic context to modify based on packet
 640  *              contents.
 641  * @data: The raw bytes of the packet.
 642  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
 643  *                 a new authentication token will be placed at the end
 644  *                 of this list for this packet.
 645  * @new_auth_tok: Pointer to a pointer to memory that this function
 646  *                allocates; sets the memory address of the pointer to
 647  *                NULL on error. This object is added to the
 648  *                auth_tok_list.
 649  * @packet_size: This function writes the size of the parsed packet
 650  *               into this memory location; zero on error.
 651  * @max_packet_size: maximum number of bytes to parse
 652  *
 653  * Returns zero on success; non-zero on error.
 654  */
 655 static int
 656 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
 657                    unsigned char *data, struct list_head *auth_tok_list,
 658                    struct ecryptfs_auth_tok **new_auth_tok,
 659                    size_t *packet_size, size_t max_packet_size)
 660 {
 661         size_t body_size;
 662         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 663         size_t length_size;
 664         int rc = 0;
 665
 666         (*packet_size) = 0;
 667         (*new_auth_tok) = NULL;
 668         /**
 669          *This format is inspired by OpenPGP; see RFC 2440
 670          * packet tag 3
 671          *
 672          * Tag 3 identifier (1 byte)
 673          * Max Tag 3 packet size (max 3 bytes)
 674          * Version (1 byte)
 675          * Cipher code (1 byte)
 676          * S2K specifier (1 byte)
 677          * Hash identifier (1 byte)
 678          * Salt (ECRYPTFS_SALT_SIZE)
 679          * Hash iterations (1 byte)
 680          * Encrypted key (arbitrary)
 681          *
 682          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
 683          */
 684         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
 685                 printk(KERN_ERR "Max packet size too large\n");
 686                 rc = -EINVAL;
 687                 goto out;
 688         }
 689         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
 690                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
 691                        ECRYPTFS_TAG_3_PACKET_TYPE);
 692                 rc = -EINVAL;
 693                 goto out;
 694         }
 695         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
 696          * at end of function upon failure */
 697         auth_tok_list_item =
 698             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
 699         if (!auth_tok_list_item) {
 700                 printk(KERN_ERR "Unable to allocate memory\n");
 701                 rc = -ENOMEM;
 702                 goto out;
 703         }
 704         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
 705         if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
 706                                       &length_size))) {
 707                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
 708                        rc);
 709                 goto out_free;
 710         }
 711         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
 712                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
 713                 rc = -EINVAL;
 714                 goto out_free;
 715         }
 716         (*packet_size) += length_size;
 717         if (unlikely((*packet_size) + body_size > max_packet_size)) {
 718                 printk(KERN_ERR "Packet size exceeds max\n");
 719                 rc = -EINVAL;
 720                 goto out_free;
 721         }
 722         (*new_auth_tok)->session_key.encrypted_key_size =
 723                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
 724         if (unlikely(data[(*packet_size)++] != 0x04)) {
 725                 printk(KERN_WARNING "Unknown version number [%d]\n",
 726                        data[(*packet_size) - 1]);
 727                 rc = -EINVAL;
 728                 goto out_free;
 729         }
 730         ecryptfs_cipher_code_to_string(crypt_stat->cipher,
 731                                        (u16)data[(*packet_size)]);
 732         /* A little extra work to differentiate among the AES key
 733          * sizes; see RFC2440 */
 734         switch(data[(*packet_size)++]) {
 735         case RFC2440_CIPHER_AES_192:
 736                 crypt_stat->key_size = 24;
 737                 break;
 738         default:
 739                 crypt_stat->key_size =
 740                         (*new_auth_tok)->session_key.encrypted_key_size;
 741         }
 742         ecryptfs_init_crypt_ctx(crypt_stat);
 743         if (unlikely(data[(*packet_size)++] != 0x03)) {
 744                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
 745                 rc = -ENOSYS;
 746                 goto out_free;
 747         }
 748         /* TODO: finish the hash mapping */
 749         switch (data[(*packet_size)++]) {
 750         case 0x01: /* See RFC2440 for these numbers and their mappings */
 751                 /* Choose MD5 */
 752                 memcpy((*new_auth_tok)->token.password.salt,
 753                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
 754                 (*packet_size) += ECRYPTFS_SALT_SIZE;
 755                 /* This conversion was taken straight from RFC2440 */
 756                 (*new_auth_tok)->token.password.hash_iterations =
 757                         ((u32) 16 + (data[(*packet_size)] & 15))
 758                                 << ((data[(*packet_size)] >> 4) + 6);
 759                 (*packet_size)++;
 760                 /* Friendly reminder:
 761                  * (*new_auth_tok)->session_key.encrypted_key_size =
 762                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
 763                 memcpy((*new_auth_tok)->session_key.encrypted_key,
 764                        &data[(*packet_size)],
 765                        (*new_auth_tok)->session_key.encrypted_key_size);
 766                 (*packet_size) +=
 767                         (*new_auth_tok)->session_key.encrypted_key_size;
 768                 (*new_auth_tok)->session_key.flags &=
 769                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 770                 (*new_auth_tok)->session_key.flags |=
 771                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
 772                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
 773                 break;
 774         default:
 775                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
 776                                 "[%d]\n", data[(*packet_size) - 1]);
 777                 rc = -ENOSYS;
 778                 goto out_free;
 779         }
 780         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
 781         /* TODO: Parametarize; we might actually want userspace to
 782          * decrypt the session key. */
 783         (*new_auth_tok)->session_key.flags &=
 784                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
 785         (*new_auth_tok)->session_key.flags &=
 786                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
 787         list_add(&auth_tok_list_item->list, auth_tok_list);
 788         goto out;
 789 out_free:
 790         (*new_auth_tok) = NULL;
 791         memset(auth_tok_list_item, 0,
 792                sizeof(struct ecryptfs_auth_tok_list_item));
 793         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 794                         auth_tok_list_item);
 795 out:
 796         if (rc)
 797                 (*packet_size) = 0;
 798         return rc;
 799 }
 800
 801 /**
 802  * parse_tag_11_packet
 803  * @data: The raw bytes of the packet
 804  * @contents: This function writes the data contents of the literal
 805  *            packet into this memory location
 806  * @max_contents_bytes: The maximum number of bytes that this function
 807  *                      is allowed to write into contents
 808  * @tag_11_contents_size: This function writes the size of the parsed
 809  *                        contents into this memory location; zero on
 810  *                        error
 811  * @packet_size: This function writes the size of the parsed packet
 812  *               into this memory location; zero on error
 813  * @max_packet_size: maximum number of bytes to parse
 814  *
 815  * Returns zero on success; non-zero on error.
 816  */
 817 static int
 818 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
 819                     size_t max_contents_bytes, size_t *tag_11_contents_size,
 820                     size_t *packet_size, size_t max_packet_size)
 821 {
 822         size_t body_size;
 823         size_t length_size;
 824         int rc = 0;
 825
 826         (*packet_size) = 0;
 827         (*tag_11_contents_size) = 0;
 828         /* This format is inspired by OpenPGP; see RFC 2440
 829          * packet tag 11
 830          *
 831          * Tag 11 identifier (1 byte)
 832          * Max Tag 11 packet size (max 3 bytes)
 833          * Binary format specifier (1 byte)
 834          * Filename length (1 byte)
 835          * Filename ("_CONSOLE") (8 bytes)
 836          * Modification date (4 bytes)
 837          * Literal data (arbitrary)
 838          *
 839          * We need at least 16 bytes of data for the packet to even be
 840          * valid.
 841          */
 842         if (max_packet_size < 16) {
 843                 printk(KERN_ERR "Maximum packet size too small\n");
 844                 rc = -EINVAL;
 845                 goto out;
 846         }
 847         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
 848                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
 849                 rc = -EINVAL;
 850                 goto out;
 851         }
 852         if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
 853                                       &length_size))) {
 854                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
 855                 goto out;
 856         }
 857         if (body_size < 14) {
 858                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
 859                 rc = -EINVAL;
 860                 goto out;
 861         }
 862         (*packet_size) += length_size;
 863         (*tag_11_contents_size) = (body_size - 14);
 864         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
 865                 printk(KERN_ERR "Packet size exceeds max\n");
 866                 rc = -EINVAL;
 867                 goto out;
 868         }
 869         if (data[(*packet_size)++] != 0x62) {
 870                 printk(KERN_WARNING "Unrecognizable packet\n");
 871                 rc = -EINVAL;
 872                 goto out;
 873         }
 874         if (data[(*packet_size)++] != 0x08) {
 875                 printk(KERN_WARNING "Unrecognizable packet\n");
 876                 rc = -EINVAL;
 877                 goto out;
 878         }
 879         (*packet_size) += 12; /* Ignore filename and modification date */
 880         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
 881         (*packet_size) += (*tag_11_contents_size);
 882 out:
 883         if (rc) {
 884                 (*packet_size) = 0;
 885                 (*tag_11_contents_size) = 0;
 886         }
 887         return rc;
 888 }
 889
 890 static int
 891 ecryptfs_find_global_auth_tok_for_sig(
 892         struct ecryptfs_global_auth_tok **global_auth_tok,
 893         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 894 {
 895         struct ecryptfs_global_auth_tok *walker;
 896         int rc = 0;
 897
 898         (*global_auth_tok) = NULL;
 899         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 900         list_for_each_entry(walker,
 901                             &mount_crypt_stat->global_auth_tok_list,
 902                             mount_crypt_stat_list) {
 903                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX) == 0) {
 904                         (*global_auth_tok) = walker;
 905                         goto out;
 906                 }
 907         }
 908         rc = -EINVAL;
 909 out:
 910         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 911         return rc;
 912 }
 913
 914 /**
 915  * ecryptfs_verify_version
 916  * @version: The version number to confirm
 917  *
 918  * Returns zero on good version; non-zero otherwise
 919  */
 920 static int ecryptfs_verify_version(u16 version)
 921 {
 922         int rc = 0;
 923         unsigned char major;
 924         unsigned char minor;
 925
 926         major = ((version >> 8) & 0xFF);
 927         minor = (version & 0xFF);
 928         if (major != ECRYPTFS_VERSION_MAJOR) {
 929                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 930                                 "Expected [%d]; got [%d]\n",
 931                                 ECRYPTFS_VERSION_MAJOR, major);
 932                 rc = -EINVAL;
 933                 goto out;
 934         }
 935         if (minor != ECRYPTFS_VERSION_MINOR) {
 936                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 937                                 "Expected [%d]; got [%d]\n",
 938                                 ECRYPTFS_VERSION_MINOR, minor);
 939                 rc = -EINVAL;
 940                 goto out;
 941         }
 942 out:
 943         return rc;
 944 }
 945
 946 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
 947                                       struct ecryptfs_auth_tok **auth_tok,
 948                                       char *sig)
 949 {
 950         int rc = 0;
 951
 952         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
 953         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
 954                 printk(KERN_ERR "Could not find key with description: [%s]\n",
 955                        sig);
 956                 process_request_key_err(PTR_ERR(*auth_tok_key));
 957                 rc = -EINVAL;
 958                 goto out;
 959         }
 960         (*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
 961         if (ecryptfs_verify_version((*auth_tok)->version)) {
 962                 printk(KERN_ERR
 963                        "Data structure version mismatch. "
 964                        "Userspace tools must match eCryptfs "
 965                        "kernel module with major version [%d] "
 966                        "and minor version [%d]\n",
 967                        ECRYPTFS_VERSION_MAJOR,
 968                        ECRYPTFS_VERSION_MINOR);
 969                 rc = -EINVAL;
 970                 goto out;
 971         }
 972         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
 973             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
 974                 printk(KERN_ERR "Invalid auth_tok structure "
 975                        "returned from key query\n");
 976                 rc = -EINVAL;
 977                 goto out;
 978         }
 979 out:
 980         return rc;
 981 }
 982
 983 /**
 984  * ecryptfs_find_auth_tok_for_sig
 985  * @auth_tok: Set to the matching auth_tok; NULL if not found
 986  * @crypt_stat: inode crypt_stat crypto context
 987  * @sig: Sig of auth_tok to find
 988  *
 989  * For now, this function simply looks at the registered auth_tok's
 990  * linked off the mount_crypt_stat, so all the auth_toks that can be
 991  * used must be registered at mount time. This function could
 992  * potentially try a lot harder to find auth_tok's (e.g., by calling
 993  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
 994  * that static registration of auth_tok's will no longer be necessary.
 995  *
 996  * Returns zero on no error; non-zero on error
 997  */
 998 static int
 999 ecryptfs_find_auth_tok_for_sig(
1000         struct ecryptfs_auth_tok **auth_tok,
1001         struct ecryptfs_crypt_stat *crypt_stat, char *sig)
1002 {
1003         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1004                 crypt_stat->mount_crypt_stat;
1005         struct ecryptfs_global_auth_tok *global_auth_tok;
1006         int rc = 0;
1007
1008         (*auth_tok) = NULL;
1009         if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
1010                                                   mount_crypt_stat, sig)) {
1011                 struct key *auth_tok_key;
1012
1013                 rc = ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key, auth_tok,
1014                                                        sig);
1015         } else
1016                 (*auth_tok) = global_auth_tok->global_auth_tok;
1017         return rc;
1018 }
1019
1020 /**
1021  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1022  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1023  * @crypt_stat: The cryptographic context
1024  *
1025  * Returns zero on success; non-zero error otherwise
1026  */
1027 static int
1028 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1029                                          struct ecryptfs_crypt_stat *crypt_stat)
1030 {
1031         struct scatterlist dst_sg;
1032         struct scatterlist src_sg;
1033         struct mutex *tfm_mutex;
1034         struct blkcipher_desc desc = {
1035                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1036         };
1037         int rc = 0;
1038
1039         if (unlikely(ecryptfs_verbosity > 0)) {
1040                 ecryptfs_printk(
1041                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1042                         auth_tok->token.password.session_key_encryption_key_bytes);
1043                 ecryptfs_dump_hex(
1044                         auth_tok->token.password.session_key_encryption_key,
1045                         auth_tok->token.password.session_key_encryption_key_bytes);
1046         }
1047         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1048                                                         crypt_stat->cipher);
1049         if (unlikely(rc)) {
1050                 printk(KERN_ERR "Internal error whilst attempting to get "
1051                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1052                        crypt_stat->cipher, rc);
1053                 goto out;
1054         }
1055         if ((rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1056                                       auth_tok->session_key.encrypted_key_size,
1057                                       &src_sg, 1)) != 1) {
1058                 printk(KERN_ERR "Internal error whilst attempting to convert "
1059                         "auth_tok->session_key.encrypted_key to scatterlist; "
1060                         "expected rc = 1; got rc = [%d]. "
1061                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1062                         auth_tok->session_key.encrypted_key_size);
1063                 goto out;
1064         }
1065         auth_tok->session_key.decrypted_key_size =
1066                 auth_tok->session_key.encrypted_key_size;
1067         if ((rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1068                                       auth_tok->session_key.decrypted_key_size,
1069                                       &dst_sg, 1)) != 1) {
1070                 printk(KERN_ERR "Internal error whilst attempting to convert "
1071                         "auth_tok->session_key.decrypted_key to scatterlist; "
1072                         "expected rc = 1; got rc = [%d]\n", rc);
1073                 goto out;
1074         }
1075         mutex_lock(tfm_mutex);
1076         rc = crypto_blkcipher_setkey(
1077                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1078                 crypt_stat->key_size);
1079         if (unlikely(rc < 0)) {
1080                 mutex_unlock(tfm_mutex);
1081                 printk(KERN_ERR "Error setting key for crypto context\n");
1082                 rc = -EINVAL;
1083                 goto out;
1084         }
1085         rc = crypto_blkcipher_decrypt(&desc, &dst_sg, &src_sg,
1086                                       auth_tok->session_key.encrypted_key_size);
1087         mutex_unlock(tfm_mutex);
1088         if (unlikely(rc)) {
1089                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1090                 goto out;
1091         }
1092         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1093         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1094                auth_tok->session_key.decrypted_key_size);
1095         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1096         if (unlikely(ecryptfs_verbosity > 0)) {
1097                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
1098                                 crypt_stat->key_size);
1099                 ecryptfs_dump_hex(crypt_stat->key,
1100                                   crypt_stat->key_size);
1101         }
1102 out:
1103         return rc;
1104 }
1105
1106 /**
1107  * ecryptfs_parse_packet_set
1108  * @crypt_stat: The cryptographic context
1109  * @src: Virtual address of region of memory containing the packets
1110  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1111  *
1112  * Get crypt_stat to have the file's session key if the requisite key
1113  * is available to decrypt the session key.
1114  *
1115  * Returns Zero if a valid authentication token was retrieved and
1116  * processed; negative value for file not encrypted or for error
1117  * conditions.
1118  */
1119 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1120                               unsigned char *src,
1121                               struct dentry *ecryptfs_dentry)
1122 {
1123         size_t i = 0;
1124         size_t found_auth_tok;
1125         size_t next_packet_is_auth_tok_packet;
1126         struct list_head auth_tok_list;
1127         struct ecryptfs_auth_tok *matching_auth_tok;
1128         struct ecryptfs_auth_tok *candidate_auth_tok;
1129         char *candidate_auth_tok_sig;
1130         size_t packet_size;
1131         struct ecryptfs_auth_tok *new_auth_tok;
1132         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1133         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1134         size_t tag_11_contents_size;
1135         size_t tag_11_packet_size;
1136         int rc = 0;
1137
1138         INIT_LIST_HEAD(&auth_tok_list);
1139         /* Parse the header to find as many packets as we can; these will be
1140          * added the our &auth_tok_list */
1141         next_packet_is_auth_tok_packet = 1;
1142         while (next_packet_is_auth_tok_packet) {
1143                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1144
1145                 switch (src[i]) {
1146                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1147                         rc = parse_tag_3_packet(crypt_stat,
1148                                                 (unsigned char *)&src[i],
1149                                                 &auth_tok_list, &new_auth_tok,
1150                                                 &packet_size, max_packet_size);
1151                         if (rc) {
1152                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1153                                                 "tag 3 packet\n");
1154                                 rc = -EIO;
1155                                 goto out_wipe_list;
1156                         }
1157                         i += packet_size;
1158                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1159                                                  sig_tmp_space,
1160                                                  ECRYPTFS_SIG_SIZE,
1161                                                  &tag_11_contents_size,
1162                                                  &tag_11_packet_size,
1163                                                  max_packet_size);
1164                         if (rc) {
1165                                 ecryptfs_printk(KERN_ERR, "No valid "
1166                                                 "(ecryptfs-specific) literal "
1167                                                 "packet containing "
1168                                                 "authentication token "
1169                                                 "signature found after "
1170                                                 "tag 3 packet\n");
1171                                 rc = -EIO;
1172                                 goto out_wipe_list;
1173                         }
1174                         i += tag_11_packet_size;
1175                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1176                                 ecryptfs_printk(KERN_ERR, "Expected "
1177                                                 "signature of size [%d]; "
1178                                                 "read size [%d]\n",
1179                                                 ECRYPTFS_SIG_SIZE,
1180                                                 tag_11_contents_size);
1181                                 rc = -EIO;
1182                                 goto out_wipe_list;
1183                         }
1184                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1185                                         sig_tmp_space, tag_11_contents_size);
1186                         new_auth_tok->token.password.signature[
1187                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1188                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1189                         break;
1190                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1191                         rc = parse_tag_1_packet(crypt_stat,
1192                                                 (unsigned char *)&src[i],
1193                                                 &auth_tok_list, &new_auth_tok,
1194                                                 &packet_size, max_packet_size);
1195                         if (rc) {
1196                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1197                                                 "tag 1 packet\n");
1198                                 rc = -EIO;
1199                                 goto out_wipe_list;
1200                         }
1201                         i += packet_size;
1202                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1203                         break;
1204                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1205                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1206                                         "(Tag 11 not allowed by itself)\n");
1207                         rc = -EIO;
1208                         goto out_wipe_list;
1209                         break;
1210                 default:
1211                         ecryptfs_printk(KERN_DEBUG, "No packet at offset "
1212                                         "[%d] of the file header; hex value of "
1213                                         "character is [0x%.2x]\n", i, src[i]);
1214                         next_packet_is_auth_tok_packet = 0;
1215                 }
1216         }
1217         if (list_empty(&auth_tok_list)) {
1218                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1219                        "eCryptfs file; this is not supported in this version "
1220                        "of the eCryptfs kernel module\n");
1221                 rc = -EINVAL;
1222                 goto out;
1223         }
1224         /* auth_tok_list contains the set of authentication tokens
1225          * parsed from the metadata. We need to find a matching
1226          * authentication token that has the secret component(s)
1227          * necessary to decrypt the EFEK in the auth_tok parsed from
1228          * the metadata. There may be several potential matches, but
1229          * just one will be sufficient to decrypt to get the FEK. */
1230 find_next_matching_auth_tok:
1231         found_auth_tok = 0;
1232         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1233                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1234                 if (unlikely(ecryptfs_verbosity > 0)) {
1235                         ecryptfs_printk(KERN_DEBUG,
1236                                         "Considering cadidate auth tok:\n");
1237                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1238                 }
1239                 if ((rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1240                                                     candidate_auth_tok))) {
1241                         printk(KERN_ERR
1242                                "Unrecognized candidate auth tok type: [%d]\n",
1243                                candidate_auth_tok->token_type);
1244                         rc = -EINVAL;
1245                         goto out_wipe_list;
1246                 }
1247                 if ((rc = ecryptfs_find_auth_tok_for_sig(
1248                              &matching_auth_tok, crypt_stat,
1249                              candidate_auth_tok_sig)))
1250                         rc = 0;
1251                 if (matching_auth_tok) {
1252                         found_auth_tok = 1;
1253                         goto found_matching_auth_tok;
1254                 }
1255         }
1256         if (!found_auth_tok) {
1257                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1258                                 "authentication token\n");
1259                 rc = -EIO;
1260                 goto out_wipe_list;
1261         }
1262 found_matching_auth_tok:
1263         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1264                 memcpy(&(candidate_auth_tok->token.private_key),
1265                        &(matching_auth_tok->token.private_key),
1266                        sizeof(struct ecryptfs_private_key));
1267                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1268                                                        crypt_stat);
1269         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1270                 memcpy(&(candidate_auth_tok->token.password),
1271                        &(matching_auth_tok->token.password),
1272                        sizeof(struct ecryptfs_password));
1273                 rc = decrypt_passphrase_encrypted_session_key(
1274                         candidate_auth_tok, crypt_stat);
1275         }
1276         if (rc) {
1277                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1278
1279                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1280                                 "session key for authentication token with sig "
1281                                 "[%.*s]; rc = [%d]. Removing auth tok "
1282                                 "candidate from the list and searching for "
1283                                 "the next match.\n", candidate_auth_tok_sig,
1284                                 ECRYPTFS_SIG_SIZE_HEX, rc);
1285                 list_for_each_entry_safe(auth_tok_list_item,
1286                                          auth_tok_list_item_tmp,
1287                                          &auth_tok_list, list) {
1288                         if (candidate_auth_tok
1289                             == &auth_tok_list_item->auth_tok) {
1290                                 list_del(&auth_tok_list_item->list);
1291                                 kmem_cache_free(
1292                                         ecryptfs_auth_tok_list_item_cache,
1293                                         auth_tok_list_item);
1294                                 goto find_next_matching_auth_tok;
1295                         }
1296                 }
1297                 BUG();
1298         }
1299         rc = ecryptfs_compute_root_iv(crypt_stat);
1300         if (rc) {
1301                 ecryptfs_printk(KERN_ERR, "Error computing "
1302                                 "the root IV\n");
1303                 goto out_wipe_list;
1304         }
1305         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1306         if (rc) {
1307                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1308                                 "context for cipher [%s]; rc = [%d]\n",
1309                                 crypt_stat->cipher, rc);
1310         }
1311 out_wipe_list:
1312         wipe_auth_tok_list(&auth_tok_list);
1313 out:
1314         return rc;
1315 }
1316
1317 static int
1318 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1319                         struct ecryptfs_crypt_stat *crypt_stat,
1320                         struct ecryptfs_key_record *key_rec)
1321 {
1322         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1323         char *netlink_payload;
1324         size_t netlink_payload_length;
1325         struct ecryptfs_message *msg;
1326         int rc;
1327
1328         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1329                                  ecryptfs_code_for_cipher_string(crypt_stat),
1330                                  crypt_stat, &netlink_payload,
1331                                  &netlink_payload_length);
1332         if (rc) {
1333                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1334                 goto out;
1335         }
1336         rc = ecryptfs_send_message(ecryptfs_transport, netlink_payload,
1337                                    netlink_payload_length, &msg_ctx);
1338         if (rc) {
1339                 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
1340                 goto out;
1341         }
1342         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1343         if (rc) {
1344                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1345                                 "from the user space daemon\n");
1346                 rc = -EIO;
1347                 goto out;
1348         }
1349         rc = parse_tag_67_packet(key_rec, msg);
1350         if (rc)
1351                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1352         kfree(msg);
1353 out:
1354         if (netlink_payload)
1355                 kfree(netlink_payload);
1356         return rc;
1357 }
1358 /**
1359  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1360  * @dest: Buffer into which to write the packet
1361  * @remaining_bytes: Maximum number of bytes that can be writtn
1362  * @auth_tok: The authentication token used for generating the tag 1 packet
1363  * @crypt_stat: The cryptographic context
1364  * @key_rec: The key record struct for the tag 1 packet
1365  * @packet_size: This function will write the number of bytes that end
1366  *               up constituting the packet; set to zero on error
1367  *
1368  * Returns zero on success; non-zero on error.
1369  */
1370 static int
1371 write_tag_1_packet(char *dest, size_t *remaining_bytes,
1372                    struct ecryptfs_auth_tok *auth_tok,
1373                    struct ecryptfs_crypt_stat *crypt_stat,
1374                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1375 {
1376         size_t i;
1377         size_t encrypted_session_key_valid = 0;
1378         size_t packet_size_length;
1379         size_t max_packet_size;
1380         int rc = 0;
1381
1382         (*packet_size) = 0;
1383         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
1384                           ECRYPTFS_SIG_SIZE);
1385         encrypted_session_key_valid = 0;
1386         for (i = 0; i < crypt_stat->key_size; i++)
1387                 encrypted_session_key_valid |=
1388                         auth_tok->session_key.encrypted_key[i];
1389         if (encrypted_session_key_valid) {
1390                 memcpy(key_rec->enc_key,
1391                        auth_tok->session_key.encrypted_key,
1392                        auth_tok->session_key.encrypted_key_size);
1393                 goto encrypted_session_key_set;
1394         }
1395         if (auth_tok->session_key.encrypted_key_size == 0)
1396                 auth_tok->session_key.encrypted_key_size =
1397                         auth_tok->token.private_key.key_size;
1398         rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
1399         if (rc) {
1400                 ecryptfs_printk(KERN_ERR, "Failed to encrypt session key "
1401                                 "via a pki");
1402                 goto out;
1403         }
1404         if (ecryptfs_verbosity > 0) {
1405                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
1406                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
1407         }
1408 encrypted_session_key_set:
1409         /* This format is inspired by OpenPGP; see RFC 2440
1410          * packet tag 1 */
1411         max_packet_size = (1                         /* Tag 1 identifier */
1412                            + 3                       /* Max Tag 1 packet size */
1413                            + 1                       /* Version */
1414                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
1415                            + 1                       /* Cipher identifier */
1416                            + key_rec->enc_key_size); /* Encrypted key size */
1417         if (max_packet_size > (*remaining_bytes)) {
1418                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1419                        "need up to [%td] bytes, but there are only [%td] "
1420                        "available\n", max_packet_size, (*remaining_bytes));
1421                 rc = -EINVAL;
1422                 goto out;
1423         }
1424         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
1425         rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
1426                                  &packet_size_length);
1427         if (rc) {
1428                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
1429                                 "header; cannot generate packet length\n");
1430                 goto out;
1431         }
1432         (*packet_size) += packet_size_length;
1433         dest[(*packet_size)++] = 0x03; /* version 3 */
1434         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
1435         (*packet_size) += ECRYPTFS_SIG_SIZE;
1436         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
1437         memcpy(&dest[(*packet_size)], key_rec->enc_key,
1438                key_rec->enc_key_size);
1439         (*packet_size) += key_rec->enc_key_size;
1440 out:
1441         if (rc)
1442                 (*packet_size) = 0;
1443         else
1444                 (*remaining_bytes) -= (*packet_size);
1445         return rc;
1446 }
1447
1448 /**
1449  * write_tag_11_packet
1450  * @dest: Target into which Tag 11 packet is to be written
1451  * @remaining_bytes: Maximum packet length
1452  * @contents: Byte array of contents to copy in
1453  * @contents_length: Number of bytes in contents
1454  * @packet_length: Length of the Tag 11 packet written; zero on error
1455  *
1456  * Returns zero on success; non-zero on error.
1457  */
1458 static int
1459 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
1460                     size_t contents_length, size_t *packet_length)
1461 {
1462         size_t packet_size_length;
1463         size_t max_packet_size;
1464         int rc = 0;
1465
1466         (*packet_length) = 0;
1467         /* This format is inspired by OpenPGP; see RFC 2440
1468          * packet tag 11 */
1469         max_packet_size = (1                   /* Tag 11 identifier */
1470                            + 3                 /* Max Tag 11 packet size */
1471                            + 1                 /* Binary format specifier */
1472                            + 1                 /* Filename length */
1473                            + 8                 /* Filename ("_CONSOLE") */
1474                            + 4                 /* Modification date */
1475                            + contents_length); /* Literal data */
1476         if (max_packet_size > (*remaining_bytes)) {
1477                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1478                        "need up to [%td] bytes, but there are only [%td] "
1479                        "available\n", max_packet_size, (*remaining_bytes));
1480                 rc = -EINVAL;
1481                 goto out;
1482         }
1483         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
1484         rc = write_packet_length(&dest[(*packet_length)],
1485                                  (max_packet_size - 4), &packet_size_length);
1486         if (rc) {
1487                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
1488                        "generate packet length. rc = [%d]\n", rc);
1489                 goto out;
1490         }
1491         (*packet_length) += packet_size_length;
1492         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
1493         dest[(*packet_length)++] = 8;
1494         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
1495         (*packet_length) += 8;
1496         memset(&dest[(*packet_length)], 0x00, 4);
1497         (*packet_length) += 4;
1498         memcpy(&dest[(*packet_length)], contents, contents_length);
1499         (*packet_length) += contents_length;
1500  out:
1501         if (rc)
1502                 (*packet_length) = 0;
1503         else
1504                 (*remaining_bytes) -= (*packet_length);
1505         return rc;
1506 }
1507
1508 /**
1509  * write_tag_3_packet
1510  * @dest: Buffer into which to write the packet
1511  * @remaining_bytes: Maximum number of bytes that can be written
1512  * @auth_tok: Authentication token
1513  * @crypt_stat: The cryptographic context
1514  * @key_rec: encrypted key
1515  * @packet_size: This function will write the number of bytes that end
1516  *               up constituting the packet; set to zero on error
1517  *
1518  * Returns zero on success; non-zero on error.
1519  */
1520 static int
1521 write_tag_3_packet(char *dest, size_t *remaining_bytes,
1522                    struct ecryptfs_auth_tok *auth_tok,
1523                    struct ecryptfs_crypt_stat *crypt_stat,
1524                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1525 {
1526         size_t i;
1527         size_t encrypted_session_key_valid = 0;
1528         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
1529         struct scatterlist dst_sg;
1530         struct scatterlist src_sg;
1531         struct mutex *tfm_mutex = NULL;
1532         size_t cipher_code;
1533         size_t packet_size_length;
1534         size_t max_packet_size;
1535         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1536                 crypt_stat->mount_crypt_stat;
1537         struct blkcipher_desc desc = {
1538                 .tfm = NULL,
1539                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1540         };
1541         int rc = 0;
1542
1543         (*packet_size) = 0;
1544         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
1545                           ECRYPTFS_SIG_SIZE);
1546         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1547                                                         crypt_stat->cipher);
1548         if (unlikely(rc)) {
1549                 printk(KERN_ERR "Internal error whilst attempting to get "
1550                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1551                        crypt_stat->cipher, rc);
1552                 goto out;
1553         }
1554         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
1555                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
1556
1557                 printk(KERN_WARNING "No key size specified at mount; "
1558                        "defaulting to [%d]\n", alg->max_keysize);
1559                 mount_crypt_stat->global_default_cipher_key_size =
1560                         alg->max_keysize;
1561         }
1562         if (crypt_stat->key_size == 0)
1563                 crypt_stat->key_size =
1564                         mount_crypt_stat->global_default_cipher_key_size;
1565         if (auth_tok->session_key.encrypted_key_size == 0)
1566                 auth_tok->session_key.encrypted_key_size =
1567                         crypt_stat->key_size;
1568         if (crypt_stat->key_size == 24
1569             && strcmp("aes", crypt_stat->cipher) == 0) {
1570                 memset((crypt_stat->key + 24), 0, 8);
1571                 auth_tok->session_key.encrypted_key_size = 32;
1572         } else
1573                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
1574         key_rec->enc_key_size =
1575                 auth_tok->session_key.encrypted_key_size;
1576         encrypted_session_key_valid = 0;
1577         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
1578                 encrypted_session_key_valid |=
1579                         auth_tok->session_key.encrypted_key[i];
1580         if (encrypted_session_key_valid) {
1581                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
1582                                 "using auth_tok->session_key.encrypted_key, "
1583                                 "where key_rec->enc_key_size = [%d]\n",
1584                                 key_rec->enc_key_size);
1585                 memcpy(key_rec->enc_key,
1586                        auth_tok->session_key.encrypted_key,
1587                        key_rec->enc_key_size);
1588                 goto encrypted_session_key_set;
1589         }
1590         if (auth_tok->token.password.flags &
1591             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
1592                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
1593                                 "session key encryption key of size [%d]\n",
1594                                 auth_tok->token.password.
1595                                 session_key_encryption_key_bytes);
1596                 memcpy(session_key_encryption_key,
1597                        auth_tok->token.password.session_key_encryption_key,
1598                        crypt_stat->key_size);
1599                 ecryptfs_printk(KERN_DEBUG,
1600                                 "Cached session key " "encryption key: \n");
1601                 if (ecryptfs_verbosity > 0)
1602                         ecryptfs_dump_hex(session_key_encryption_key, 16);
1603         }
1604         if (unlikely(ecryptfs_verbosity > 0)) {
1605                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
1606                 ecryptfs_dump_hex(session_key_encryption_key, 16);
1607         }
1608         if ((rc = virt_to_scatterlist(crypt_stat->key,
1609                                       key_rec->enc_key_size, &src_sg, 1))
1610             != 1) {
1611                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1612                                 "for crypt_stat session key; expected rc = 1; "
1613                                 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1614                                 rc, key_rec->enc_key_size);
1615                 rc = -ENOMEM;
1616                 goto out;
1617         }
1618         if ((rc = virt_to_scatterlist(key_rec->enc_key,
1619                                       key_rec->enc_key_size, &dst_sg, 1))
1620             != 1) {
1621                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1622                                 "for crypt_stat encrypted session key; "
1623                                 "expected rc = 1; got rc = [%d]. "
1624                                 "key_rec->enc_key_size = [%d]\n", rc,
1625                                 key_rec->enc_key_size);
1626                 rc = -ENOMEM;
1627                 goto out;
1628         }
1629         mutex_lock(tfm_mutex);
1630         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
1631                                      crypt_stat->key_size);
1632         if (rc < 0) {
1633                 mutex_unlock(tfm_mutex);
1634                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
1635                                 "context; rc = [%d]\n", rc);
1636                 goto out;
1637         }
1638         rc = 0;
1639         ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
1640                         crypt_stat->key_size);
1641         rc = crypto_blkcipher_encrypt(&desc, &dst_sg, &src_sg,
1642                                       (*key_rec).enc_key_size);
1643         mutex_unlock(tfm_mutex);
1644         if (rc) {
1645                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
1646                 goto out;
1647         }
1648         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
1649         if (ecryptfs_verbosity > 0) {
1650                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
1651                                 key_rec->enc_key_size);
1652                 ecryptfs_dump_hex(key_rec->enc_key,
1653                                   key_rec->enc_key_size);
1654         }
1655 encrypted_session_key_set:
1656         /* This format is inspired by OpenPGP; see RFC 2440
1657          * packet tag 3 */
1658         max_packet_size = (1                         /* Tag 3 identifier */
1659                            + 3                       /* Max Tag 3 packet size */
1660                            + 1                       /* Version */
1661                            + 1                       /* Cipher code */
1662                            + 1                       /* S2K specifier */
1663                            + 1                       /* Hash identifier */
1664                            + ECRYPTFS_SALT_SIZE      /* Salt */
1665                            + 1                       /* Hash iterations */
1666                            + key_rec->enc_key_size); /* Encrypted key size */
1667         if (max_packet_size > (*remaining_bytes)) {
1668                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
1669                        "there are only [%td] available\n", max_packet_size,
1670                        (*remaining_bytes));
1671                 rc = -EINVAL;
1672                 goto out;
1673         }
1674         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
1675         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1676          * to get the number of octets in the actual Tag 3 packet */
1677         rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
1678                                  &packet_size_length);
1679         if (rc) {
1680                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
1681                        "generate packet length. rc = [%d]\n", rc);
1682                 goto out;
1683         }
1684         (*packet_size) += packet_size_length;
1685         dest[(*packet_size)++] = 0x04; /* version 4 */
1686         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1687          * specified with strings */
1688         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat);
1689         if (cipher_code == 0) {
1690                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
1691                                 "cipher [%s]\n", crypt_stat->cipher);
1692                 rc = -EINVAL;
1693                 goto out;
1694         }
1695         dest[(*packet_size)++] = cipher_code;
1696         dest[(*packet_size)++] = 0x03;  /* S2K */
1697         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
1698         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
1699                ECRYPTFS_SALT_SIZE);
1700         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
1701         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
1702         memcpy(&dest[(*packet_size)], key_rec->enc_key,
1703                key_rec->enc_key_size);
1704         (*packet_size) += key_rec->enc_key_size;
1705 out:
1706         if (rc)
1707                 (*packet_size) = 0;
1708         else
1709                 (*remaining_bytes) -= (*packet_size);
1710         return rc;
1711 }
1712
1713 struct kmem_cache *ecryptfs_key_record_cache;
1714
1715 /**
1716  * ecryptfs_generate_key_packet_set
1717  * @dest_base: Virtual address from which to write the key record set
1718  * @crypt_stat: The cryptographic context from which the
1719  *              authentication tokens will be retrieved
1720  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1721  *                   for the global parameters
1722  * @len: The amount written
1723  * @max: The maximum amount of data allowed to be written
1724  *
1725  * Generates a key packet set and writes it to the virtual address
1726  * passed in.
1727  *
1728  * Returns zero on success; non-zero on error.
1729  */
1730 int
1731 ecryptfs_generate_key_packet_set(char *dest_base,
1732                                  struct ecryptfs_crypt_stat *crypt_stat,
1733                                  struct dentry *ecryptfs_dentry, size_t *len,
1734                                  size_t max)
1735 {
1736         struct ecryptfs_auth_tok *auth_tok;
1737         struct ecryptfs_global_auth_tok *global_auth_tok;
1738         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1739                 &ecryptfs_superblock_to_private(
1740                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
1741         size_t written;
1742         struct ecryptfs_key_record *key_rec;
1743         struct ecryptfs_key_sig *key_sig;
1744         int rc = 0;
1745
1746         (*len) = 0;
1747         mutex_lock(&crypt_stat->keysig_list_mutex);
1748         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
1749         if (!key_rec) {
1750                 rc = -ENOMEM;
1751                 goto out;
1752         }
1753         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
1754                             crypt_stat_list) {
1755                 memset(key_rec, 0, sizeof(*key_rec));
1756                 rc = ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
1757                                                            mount_crypt_stat,
1758                                                            key_sig->keysig);
1759                 if (rc) {
1760                         printk(KERN_ERR "Error attempting to get the global "
1761                                "auth_tok; rc = [%d]\n", rc);
1762                         goto out_free;
1763                 }
1764                 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
1765                         printk(KERN_WARNING
1766                                "Skipping invalid auth tok with sig = [%s]\n",
1767                                global_auth_tok->sig);
1768                         continue;
1769                 }
1770                 auth_tok = global_auth_tok->global_auth_tok;
1771                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
1772                         rc = write_tag_3_packet((dest_base + (*len)),
1773                                                 &max, auth_tok,
1774                                                 crypt_stat, key_rec,
1775                                                 &written);
1776                         if (rc) {
1777                                 ecryptfs_printk(KERN_WARNING, "Error "
1778                                                 "writing tag 3 packet\n");
1779                                 goto out_free;
1780                         }
1781                         (*len) += written;
1782                         /* Write auth tok signature packet */
1783                         rc = write_tag_11_packet((dest_base + (*len)), &max,
1784                                                  key_rec->sig,
1785                                                  ECRYPTFS_SIG_SIZE, &written);
1786                         if (rc) {
1787                                 ecryptfs_printk(KERN_ERR, "Error writing "
1788                                                 "auth tok signature packet\n");
1789                                 goto out_free;
1790                         }
1791                         (*len) += written;
1792                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1793                         rc = write_tag_1_packet(dest_base + (*len),
1794                                                 &max, auth_tok,
1795                                                 crypt_stat, key_rec, &written);
1796                         if (rc) {
1797                                 ecryptfs_printk(KERN_WARNING, "Error "
1798                                                 "writing tag 1 packet\n");
1799                                 goto out_free;
1800                         }
1801                         (*len) += written;
1802                 } else {
1803                         ecryptfs_printk(KERN_WARNING, "Unsupported "
1804                                         "authentication token type\n");
1805                         rc = -EINVAL;
1806                         goto out_free;
1807                 }
1808         }
1809         if (likely(max > 0)) {
1810                 dest_base[(*len)] = 0x00;
1811         } else {
1812                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
1813                 rc = -EIO;
1814         }
1815 out_free:
1816         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
1817 out:
1818         if (rc)
1819                 (*len) = 0;
1820         mutex_unlock(&crypt_stat->keysig_list_mutex);
1821         return rc;
1822 }
1823
1824 struct kmem_cache *ecryptfs_key_sig_cache;
1825
1826 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
1827 {
1828         struct ecryptfs_key_sig *new_key_sig;
1829         int rc = 0;
1830
1831         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
1832         if (!new_key_sig) {
1833                 rc = -ENOMEM;
1834                 printk(KERN_ERR
1835                        "Error allocating from ecryptfs_key_sig_cache\n");
1836                 goto out;
1837         }
1838         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
1839         mutex_lock(&crypt_stat->keysig_list_mutex);
1840         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
1841         mutex_unlock(&crypt_stat->keysig_list_mutex);
1842 out:
1843         return rc;
1844 }
1845
1846 struct kmem_cache *ecryptfs_global_auth_tok_cache;
1847
1848 int
1849 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1850                              char *sig)
1851 {
1852         struct ecryptfs_global_auth_tok *new_auth_tok;
1853         int rc = 0;
1854
1855         new_auth_tok = kmem_cache_alloc(ecryptfs_global_auth_tok_cache,
1856                                         GFP_KERNEL);
1857         if (!new_auth_tok) {
1858                 rc = -ENOMEM;
1859                 printk(KERN_ERR "Error allocating from "
1860                        "ecryptfs_global_auth_tok_cache\n");
1861                 goto out;
1862         }
1863         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
1864         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
1865         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
1866         list_add(&new_auth_tok->mount_crypt_stat_list,
1867                  &mount_crypt_stat->global_auth_tok_list);
1868         mount_crypt_stat->num_global_auth_toks++;
1869         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
1870 out:
1871         return rc;
1872 }
1873