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  * ecryptfs_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 int ecryptfs_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  * ecryptfs_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 int ecryptfs_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 = ecryptfs_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 = ecryptfs_write_packet_length(&message[i],
 176                                           session_key->encrypted_key_size,
 177                                           &packet_size_len);
 178         if (rc) {
 179                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 180                                 "header; cannot generate packet length\n");
 181                 goto out;
 182         }
 183         i += packet_size_len;
 184         memcpy(&message[i], session_key->encrypted_key,
 185                session_key->encrypted_key_size);
 186         i += session_key->encrypted_key_size;
 187         *packet_len = i;
 188 out:
 189         return rc;
 190 }
 191
 192 static int
 193 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
 194                     struct ecryptfs_message *msg)
 195 {
 196         size_t i = 0;
 197         char *data;
 198         size_t data_len;
 199         size_t m_size;
 200         size_t message_len;
 201         u16 checksum = 0;
 202         u16 expected_checksum = 0;
 203         int rc;
 204
 205         /*
 206          *              ***** TAG 65 Packet Format *****
 207          *         | Content Type             | 1 byte       |
 208          *         | Status Indicator         | 1 byte       |
 209          *         | File Encryption Key Size | 1 or 2 bytes |
 210          *         | File Encryption Key      | arbitrary    |
 211          */
 212         message_len = msg->data_len;
 213         data = msg->data;
 214         if (message_len < 4) {
 215                 rc = -EIO;
 216                 goto out;
 217         }
 218         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
 219                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
 220                 rc = -EIO;
 221                 goto out;
 222         }
 223         if (data[i++]) {
 224                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
 225                                 "[%d]\n", data[i-1]);
 226                 rc = -EIO;
 227                 goto out;
 228         }
 229         rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
 230         if (rc) {
 231                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 232                                 "rc = [%d]\n", rc);
 233                 goto out;
 234         }
 235         i += data_len;
 236         if (message_len < (i + m_size)) {
 237                 ecryptfs_printk(KERN_ERR, "The received netlink message is "
 238                                 "shorter than expected\n");
 239                 rc = -EIO;
 240                 goto out;
 241         }
 242         if (m_size < 3) {
 243                 ecryptfs_printk(KERN_ERR,
 244                                 "The decrypted key is not long enough to "
 245                                 "include a cipher code and checksum\n");
 246                 rc = -EIO;
 247                 goto out;
 248         }
 249         *cipher_code = data[i++];
 250         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
 251         session_key->decrypted_key_size = m_size - 3;
 252         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
 253                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
 254                                 "the maximum key size [%d]\n",
 255                                 session_key->decrypted_key_size,
 256                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 257                 rc = -EIO;
 258                 goto out;
 259         }
 260         memcpy(session_key->decrypted_key, &data[i],
 261                session_key->decrypted_key_size);
 262         i += session_key->decrypted_key_size;
 263         expected_checksum += (unsigned char)(data[i++]) << 8;
 264         expected_checksum += (unsigned char)(data[i++]);
 265         for (i = 0; i < session_key->decrypted_key_size; i++)
 266                 checksum += session_key->decrypted_key[i];
 267         if (expected_checksum != checksum) {
 268                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
 269                                 "encryption  key; expected [%x]; calculated "
 270                                 "[%x]\n", expected_checksum, checksum);
 271                 rc = -EIO;
 272         }
 273 out:
 274         return rc;
 275 }
 276
 277
 278 static int
 279 write_tag_66_packet(char *signature, u8 cipher_code,
 280                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
 281                     size_t *packet_len)
 282 {
 283         size_t i = 0;
 284         size_t j;
 285         size_t data_len;
 286         size_t checksum = 0;
 287         size_t packet_size_len;
 288         char *message;
 289         int rc;
 290
 291         /*
 292          *              ***** TAG 66 Packet Format *****
 293          *         | Content Type             | 1 byte       |
 294          *         | Key Identifier Size      | 1 or 2 bytes |
 295          *         | Key Identifier           | arbitrary    |
 296          *         | File Encryption Key Size | 1 or 2 bytes |
 297          *         | File Encryption Key      | arbitrary    |
 298          */
 299         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
 300         *packet = kmalloc(data_len, GFP_KERNEL);
 301         message = *packet;
 302         if (!message) {
 303                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 304                 rc = -ENOMEM;
 305                 goto out;
 306         }
 307         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
 308         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 309                                           &packet_size_len);
 310         if (rc) {
 311                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 312                                 "header; cannot generate packet length\n");
 313                 goto out;
 314         }
 315         i += packet_size_len;
 316         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 317         i += ECRYPTFS_SIG_SIZE_HEX;
 318         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
 319         rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
 320                                           &packet_size_len);
 321         if (rc) {
 322                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 323                                 "header; cannot generate packet length\n");
 324                 goto out;
 325         }
 326         i += packet_size_len;
 327         message[i++] = cipher_code;
 328         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
 329         i += crypt_stat->key_size;
 330         for (j = 0; j < crypt_stat->key_size; j++)
 331                 checksum += crypt_stat->key[j];
 332         message[i++] = (checksum / 256) % 256;
 333         message[i++] = (checksum % 256);
 334         *packet_len = i;
 335 out:
 336         return rc;
 337 }
 338
 339 static int
 340 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
 341                     struct ecryptfs_message *msg)
 342 {
 343         size_t i = 0;
 344         char *data;
 345         size_t data_len;
 346         size_t message_len;
 347         int rc;
 348
 349         /*
 350          *              ***** TAG 65 Packet Format *****
 351          *    | Content Type                       | 1 byte       |
 352          *    | Status Indicator                   | 1 byte       |
 353          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 354          *    | Encrypted File Encryption Key      | arbitrary    |
 355          */
 356         message_len = msg->data_len;
 357         data = msg->data;
 358         /* verify that everything through the encrypted FEK size is present */
 359         if (message_len < 4) {
 360                 rc = -EIO;
 361                 printk(KERN_ERR "%s: message_len is [%Zd]; minimum acceptable "
 362                        "message length is [%d]\n", __func__, message_len, 4);
 363                 goto out;
 364         }
 365         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
 366                 rc = -EIO;
 367                 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
 368                        __func__);
 369                 goto out;
 370         }
 371         if (data[i++]) {
 372                 rc = -EIO;
 373                 printk(KERN_ERR "%s: Status indicator has non zero "
 374                        "value [%d]\n", __func__, data[i-1]);
 375
 376                 goto out;
 377         }
 378         rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
 379                                           &data_len);
 380         if (rc) {
 381                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 382                                 "rc = [%d]\n", rc);
 383                 goto out;
 384         }
 385         i += data_len;
 386         if (message_len < (i + key_rec->enc_key_size)) {
 387                 rc = -EIO;
 388                 printk(KERN_ERR "%s: message_len [%Zd]; max len is [%Zd]\n",
 389                        __func__, message_len, (i + key_rec->enc_key_size));
 390                 goto out;
 391         }
 392         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 393                 rc = -EIO;
 394                 printk(KERN_ERR "%s: Encrypted key_size [%Zd] larger than "
 395                        "the maximum key size [%d]\n", __func__,
 396                        key_rec->enc_key_size,
 397                        ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 398                 goto out;
 399         }
 400         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
 401 out:
 402         return rc;
 403 }
 404
 405 static int
 406 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
 407 {
 408         int rc = 0;
 409
 410         (*sig) = NULL;
 411         switch (auth_tok->token_type) {
 412         case ECRYPTFS_PASSWORD:
 413                 (*sig) = auth_tok->token.password.signature;
 414                 break;
 415         case ECRYPTFS_PRIVATE_KEY:
 416                 (*sig) = auth_tok->token.private_key.signature;
 417                 break;
 418         default:
 419                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
 420                        auth_tok->token_type);
 421                 rc = -EINVAL;
 422         }
 423         return rc;
 424 }
 425
 426 /**
 427  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
 428  * @auth_tok: The key authentication token used to decrypt the session key
 429  * @crypt_stat: The cryptographic context
 430  *
 431  * Returns zero on success; non-zero error otherwise.
 432  */
 433 static int
 434 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
 435                                   struct ecryptfs_crypt_stat *crypt_stat)
 436 {
 437         u8 cipher_code = 0;
 438         struct ecryptfs_msg_ctx *msg_ctx;
 439         struct ecryptfs_message *msg = NULL;
 440         char *auth_tok_sig;
 441         char *netlink_message;
 442         size_t netlink_message_length;
 443         int rc;
 444
 445         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
 446         if (rc) {
 447                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
 448                        auth_tok->token_type);
 449                 goto out;
 450         }
 451         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
 452                                  &netlink_message, &netlink_message_length);
 453         if (rc) {
 454                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
 455                 goto out;
 456         }
 457         rc = ecryptfs_send_message(ecryptfs_transport, netlink_message,
 458                                    netlink_message_length, &msg_ctx);
 459         if (rc) {
 460                 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
 461                 goto out;
 462         }
 463         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
 464         if (rc) {
 465                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
 466                                 "from the user space daemon\n");
 467                 rc = -EIO;
 468                 goto out;
 469         }
 470         rc = parse_tag_65_packet(&(auth_tok->session_key),
 471                                  &cipher_code, msg);
 472         if (rc) {
 473                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
 474                        rc);
 475                 goto out;
 476         }
 477         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 478         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
 479                auth_tok->session_key.decrypted_key_size);
 480         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
 481         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
 482         if (rc) {
 483                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
 484                                 cipher_code)
 485                 goto out;
 486         }
 487         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
 488         if (ecryptfs_verbosity > 0) {
 489                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
 490                 ecryptfs_dump_hex(crypt_stat->key,
 491                                   crypt_stat->key_size);
 492         }
 493 out:
 494         if (msg)
 495                 kfree(msg);
 496         return rc;
 497 }
 498
 499 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
 500 {
 501         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 502         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
 503
 504         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
 505                                  auth_tok_list_head, list) {
 506                 list_del(&auth_tok_list_item->list);
 507                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 508                                 auth_tok_list_item);
 509         }
 510 }
 511
 512 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
 513
 514 /**
 515  * parse_tag_1_packet
 516  * @crypt_stat: The cryptographic context to modify based on packet contents
 517  * @data: The raw bytes of the packet.
 518  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
 519  *                 a new authentication token will be placed at the
 520  *                 end of this list for this packet.
 521  * @new_auth_tok: Pointer to a pointer to memory that this function
 522  *                allocates; sets the memory address of the pointer to
 523  *                NULL on error. This object is added to the
 524  *                auth_tok_list.
 525  * @packet_size: This function writes the size of the parsed packet
 526  *               into this memory location; zero on error.
 527  * @max_packet_size: The maximum allowable packet size
 528  *
 529  * Returns zero on success; non-zero on error.
 530  */
 531 static int
 532 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
 533                    unsigned char *data, struct list_head *auth_tok_list,
 534                    struct ecryptfs_auth_tok **new_auth_tok,
 535                    size_t *packet_size, size_t max_packet_size)
 536 {
 537         size_t body_size;
 538         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 539         size_t length_size;
 540         int rc = 0;
 541
 542         (*packet_size) = 0;
 543         (*new_auth_tok) = NULL;
 544         /**
 545          * This format is inspired by OpenPGP; see RFC 2440
 546          * packet tag 1
 547          *
 548          * Tag 1 identifier (1 byte)
 549          * Max Tag 1 packet size (max 3 bytes)
 550          * Version (1 byte)
 551          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
 552          * Cipher identifier (1 byte)
 553          * Encrypted key size (arbitrary)
 554          *
 555          * 12 bytes minimum packet size
 556          */
 557         if (unlikely(max_packet_size < 12)) {
 558                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
 559                 rc = -EINVAL;
 560                 goto out;
 561         }
 562         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
 563                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
 564                        ECRYPTFS_TAG_1_PACKET_TYPE);
 565                 rc = -EINVAL;
 566                 goto out;
 567         }
 568         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
 569          * at end of function upon failure */
 570         auth_tok_list_item =
 571                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
 572                                   GFP_KERNEL);
 573         if (!auth_tok_list_item) {
 574                 printk(KERN_ERR "Unable to allocate memory\n");
 575                 rc = -ENOMEM;
 576                 goto out;
 577         }
 578         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
 579         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
 580                                           &length_size);
 581         if (rc) {
 582                 printk(KERN_WARNING "Error parsing packet length; "
 583                        "rc = [%d]\n", rc);
 584                 goto out_free;
 585         }
 586         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
 587                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
 588                 rc = -EINVAL;
 589                 goto out_free;
 590         }
 591         (*packet_size) += length_size;
 592         if (unlikely((*packet_size) + body_size > max_packet_size)) {
 593                 printk(KERN_WARNING "Packet size exceeds max\n");
 594                 rc = -EINVAL;
 595                 goto out_free;
 596         }
 597         if (unlikely(data[(*packet_size)++] != 0x03)) {
 598                 printk(KERN_WARNING "Unknown version number [%d]\n",
 599                        data[(*packet_size) - 1]);
 600                 rc = -EINVAL;
 601                 goto out_free;
 602         }
 603         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
 604                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
 605         *packet_size += ECRYPTFS_SIG_SIZE;
 606         /* This byte is skipped because the kernel does not need to
 607          * know which public key encryption algorithm was used */
 608         (*packet_size)++;
 609         (*new_auth_tok)->session_key.encrypted_key_size =
 610                 body_size - (ECRYPTFS_SIG_SIZE + 2);
 611         if ((*new_auth_tok)->session_key.encrypted_key_size
 612             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 613                 printk(KERN_WARNING "Tag 1 packet contains key larger "
 614                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
 615                 rc = -EINVAL;
 616                 goto out;
 617         }
 618         memcpy((*new_auth_tok)->session_key.encrypted_key,
 619                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
 620         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
 621         (*new_auth_tok)->session_key.flags &=
 622                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 623         (*new_auth_tok)->session_key.flags |=
 624                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
 625         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
 626         (*new_auth_tok)->flags = 0;
 627         (*new_auth_tok)->session_key.flags &=
 628                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
 629         (*new_auth_tok)->session_key.flags &=
 630                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
 631         list_add(&auth_tok_list_item->list, auth_tok_list);
 632         goto out;
 633 out_free:
 634         (*new_auth_tok) = NULL;
 635         memset(auth_tok_list_item, 0,
 636                sizeof(struct ecryptfs_auth_tok_list_item));
 637         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 638                         auth_tok_list_item);
 639 out:
 640         if (rc)
 641                 (*packet_size) = 0;
 642         return rc;
 643 }
 644
 645 /**
 646  * parse_tag_3_packet
 647  * @crypt_stat: The cryptographic context to modify based on packet
 648  *              contents.
 649  * @data: The raw bytes of the packet.
 650  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
 651  *                 a new authentication token will be placed at the end
 652  *                 of this list for this packet.
 653  * @new_auth_tok: Pointer to a pointer to memory that this function
 654  *                allocates; sets the memory address of the pointer to
 655  *                NULL on error. This object is added to the
 656  *                auth_tok_list.
 657  * @packet_size: This function writes the size of the parsed packet
 658  *               into this memory location; zero on error.
 659  * @max_packet_size: maximum number of bytes to parse
 660  *
 661  * Returns zero on success; non-zero on error.
 662  */
 663 static int
 664 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
 665                    unsigned char *data, struct list_head *auth_tok_list,
 666                    struct ecryptfs_auth_tok **new_auth_tok,
 667                    size_t *packet_size, size_t max_packet_size)
 668 {
 669         size_t body_size;
 670         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
 671         size_t length_size;
 672         int rc = 0;
 673
 674         (*packet_size) = 0;
 675         (*new_auth_tok) = NULL;
 676         /**
 677          *This format is inspired by OpenPGP; see RFC 2440
 678          * packet tag 3
 679          *
 680          * Tag 3 identifier (1 byte)
 681          * Max Tag 3 packet size (max 3 bytes)
 682          * Version (1 byte)
 683          * Cipher code (1 byte)
 684          * S2K specifier (1 byte)
 685          * Hash identifier (1 byte)
 686          * Salt (ECRYPTFS_SALT_SIZE)
 687          * Hash iterations (1 byte)
 688          * Encrypted key (arbitrary)
 689          *
 690          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
 691          */
 692         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
 693                 printk(KERN_ERR "Max packet size too large\n");
 694                 rc = -EINVAL;
 695                 goto out;
 696         }
 697         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
 698                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
 699                        ECRYPTFS_TAG_3_PACKET_TYPE);
 700                 rc = -EINVAL;
 701                 goto out;
 702         }
 703         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
 704          * at end of function upon failure */
 705         auth_tok_list_item =
 706             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
 707         if (!auth_tok_list_item) {
 708                 printk(KERN_ERR "Unable to allocate memory\n");
 709                 rc = -ENOMEM;
 710                 goto out;
 711         }
 712         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
 713         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
 714                                           &length_size);
 715         if (rc) {
 716                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
 717                        rc);
 718                 goto out_free;
 719         }
 720         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
 721                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
 722                 rc = -EINVAL;
 723                 goto out_free;
 724         }
 725         (*packet_size) += length_size;
 726         if (unlikely((*packet_size) + body_size > max_packet_size)) {
 727                 printk(KERN_ERR "Packet size exceeds max\n");
 728                 rc = -EINVAL;
 729                 goto out_free;
 730         }
 731         (*new_auth_tok)->session_key.encrypted_key_size =
 732                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
 733         if (unlikely(data[(*packet_size)++] != 0x04)) {
 734                 printk(KERN_WARNING "Unknown version number [%d]\n",
 735                        data[(*packet_size) - 1]);
 736                 rc = -EINVAL;
 737                 goto out_free;
 738         }
 739         ecryptfs_cipher_code_to_string(crypt_stat->cipher,
 740                                        (u16)data[(*packet_size)]);
 741         /* A little extra work to differentiate among the AES key
 742          * sizes; see RFC2440 */
 743         switch(data[(*packet_size)++]) {
 744         case RFC2440_CIPHER_AES_192:
 745                 crypt_stat->key_size = 24;
 746                 break;
 747         default:
 748                 crypt_stat->key_size =
 749                         (*new_auth_tok)->session_key.encrypted_key_size;
 750         }
 751         ecryptfs_init_crypt_ctx(crypt_stat);
 752         if (unlikely(data[(*packet_size)++] != 0x03)) {
 753                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
 754                 rc = -ENOSYS;
 755                 goto out_free;
 756         }
 757         /* TODO: finish the hash mapping */
 758         switch (data[(*packet_size)++]) {
 759         case 0x01: /* See RFC2440 for these numbers and their mappings */
 760                 /* Choose MD5 */
 761                 memcpy((*new_auth_tok)->token.password.salt,
 762                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
 763                 (*packet_size) += ECRYPTFS_SALT_SIZE;
 764                 /* This conversion was taken straight from RFC2440 */
 765                 (*new_auth_tok)->token.password.hash_iterations =
 766                         ((u32) 16 + (data[(*packet_size)] & 15))
 767                                 << ((data[(*packet_size)] >> 4) + 6);
 768                 (*packet_size)++;
 769                 /* Friendly reminder:
 770                  * (*new_auth_tok)->session_key.encrypted_key_size =
 771                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
 772                 memcpy((*new_auth_tok)->session_key.encrypted_key,
 773                        &data[(*packet_size)],
 774                        (*new_auth_tok)->session_key.encrypted_key_size);
 775                 (*packet_size) +=
 776                         (*new_auth_tok)->session_key.encrypted_key_size;
 777                 (*new_auth_tok)->session_key.flags &=
 778                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
 779                 (*new_auth_tok)->session_key.flags |=
 780                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
 781                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
 782                 break;
 783         default:
 784                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
 785                                 "[%d]\n", data[(*packet_size) - 1]);
 786                 rc = -ENOSYS;
 787                 goto out_free;
 788         }
 789         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
 790         /* TODO: Parametarize; we might actually want userspace to
 791          * decrypt the session key. */
 792         (*new_auth_tok)->session_key.flags &=
 793                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
 794         (*new_auth_tok)->session_key.flags &=
 795                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
 796         list_add(&auth_tok_list_item->list, auth_tok_list);
 797         goto out;
 798 out_free:
 799         (*new_auth_tok) = NULL;
 800         memset(auth_tok_list_item, 0,
 801                sizeof(struct ecryptfs_auth_tok_list_item));
 802         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
 803                         auth_tok_list_item);
 804 out:
 805         if (rc)
 806                 (*packet_size) = 0;
 807         return rc;
 808 }
 809
 810 /**
 811  * parse_tag_11_packet
 812  * @data: The raw bytes of the packet
 813  * @contents: This function writes the data contents of the literal
 814  *            packet into this memory location
 815  * @max_contents_bytes: The maximum number of bytes that this function
 816  *                      is allowed to write into contents
 817  * @tag_11_contents_size: This function writes the size of the parsed
 818  *                        contents into this memory location; zero on
 819  *                        error
 820  * @packet_size: This function writes the size of the parsed packet
 821  *               into this memory location; zero on error
 822  * @max_packet_size: maximum number of bytes to parse
 823  *
 824  * Returns zero on success; non-zero on error.
 825  */
 826 static int
 827 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
 828                     size_t max_contents_bytes, size_t *tag_11_contents_size,
 829                     size_t *packet_size, size_t max_packet_size)
 830 {
 831         size_t body_size;
 832         size_t length_size;
 833         int rc = 0;
 834
 835         (*packet_size) = 0;
 836         (*tag_11_contents_size) = 0;
 837         /* This format is inspired by OpenPGP; see RFC 2440
 838          * packet tag 11
 839          *
 840          * Tag 11 identifier (1 byte)
 841          * Max Tag 11 packet size (max 3 bytes)
 842          * Binary format specifier (1 byte)
 843          * Filename length (1 byte)
 844          * Filename ("_CONSOLE") (8 bytes)
 845          * Modification date (4 bytes)
 846          * Literal data (arbitrary)
 847          *
 848          * We need at least 16 bytes of data for the packet to even be
 849          * valid.
 850          */
 851         if (max_packet_size < 16) {
 852                 printk(KERN_ERR "Maximum packet size too small\n");
 853                 rc = -EINVAL;
 854                 goto out;
 855         }
 856         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
 857                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
 858                 rc = -EINVAL;
 859                 goto out;
 860         }
 861         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
 862                                           &length_size);
 863         if (rc) {
 864                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
 865                 goto out;
 866         }
 867         if (body_size < 14) {
 868                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
 869                 rc = -EINVAL;
 870                 goto out;
 871         }
 872         (*packet_size) += length_size;
 873         (*tag_11_contents_size) = (body_size - 14);
 874         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
 875                 printk(KERN_ERR "Packet size exceeds max\n");
 876                 rc = -EINVAL;
 877                 goto out;
 878         }
 879         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
 880                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
 881                        "expected size\n");
 882                 rc = -EINVAL;
 883                 goto out;
 884         }
 885         if (data[(*packet_size)++] != 0x62) {
 886                 printk(KERN_WARNING "Unrecognizable packet\n");
 887                 rc = -EINVAL;
 888                 goto out;
 889         }
 890         if (data[(*packet_size)++] != 0x08) {
 891                 printk(KERN_WARNING "Unrecognizable packet\n");
 892                 rc = -EINVAL;
 893                 goto out;
 894         }
 895         (*packet_size) += 12; /* Ignore filename and modification date */
 896         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
 897         (*packet_size) += (*tag_11_contents_size);
 898 out:
 899         if (rc) {
 900                 (*packet_size) = 0;
 901                 (*tag_11_contents_size) = 0;
 902         }
 903         return rc;
 904 }
 905
 906 static int
 907 ecryptfs_find_global_auth_tok_for_sig(
 908         struct ecryptfs_global_auth_tok **global_auth_tok,
 909         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 910 {
 911         struct ecryptfs_global_auth_tok *walker;
 912         int rc = 0;
 913
 914         (*global_auth_tok) = NULL;
 915         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 916         list_for_each_entry(walker,
 917                             &mount_crypt_stat->global_auth_tok_list,
 918                             mount_crypt_stat_list) {
 919                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX) == 0) {
 920                         (*global_auth_tok) = walker;
 921                         goto out;
 922                 }
 923         }
 924         rc = -EINVAL;
 925 out:
 926         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 927         return rc;
 928 }
 929
 930 /**
 931  * ecryptfs_verify_version
 932  * @version: The version number to confirm
 933  *
 934  * Returns zero on good version; non-zero otherwise
 935  */
 936 static int ecryptfs_verify_version(u16 version)
 937 {
 938         int rc = 0;
 939         unsigned char major;
 940         unsigned char minor;
 941
 942         major = ((version >> 8) & 0xFF);
 943         minor = (version & 0xFF);
 944         if (major != ECRYPTFS_VERSION_MAJOR) {
 945                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 946                                 "Expected [%d]; got [%d]\n",
 947                                 ECRYPTFS_VERSION_MAJOR, major);
 948                 rc = -EINVAL;
 949                 goto out;
 950         }
 951         if (minor != ECRYPTFS_VERSION_MINOR) {
 952                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 953                                 "Expected [%d]; got [%d]\n",
 954                                 ECRYPTFS_VERSION_MINOR, minor);
 955                 rc = -EINVAL;
 956                 goto out;
 957         }
 958 out:
 959         return rc;
 960 }
 961
 962 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
 963                                       struct ecryptfs_auth_tok **auth_tok,
 964                                       char *sig)
 965 {
 966         int rc = 0;
 967
 968         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
 969         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
 970                 printk(KERN_ERR "Could not find key with description: [%s]\n",
 971                        sig);
 972                 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
 973                 goto out;
 974         }
 975         (*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
 976         if (ecryptfs_verify_version((*auth_tok)->version)) {
 977                 printk(KERN_ERR
 978                        "Data structure version mismatch. "
 979                        "Userspace tools must match eCryptfs "
 980                        "kernel module with major version [%d] "
 981                        "and minor version [%d]\n",
 982                        ECRYPTFS_VERSION_MAJOR,
 983                        ECRYPTFS_VERSION_MINOR);
 984                 rc = -EINVAL;
 985                 goto out;
 986         }
 987         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
 988             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
 989                 printk(KERN_ERR "Invalid auth_tok structure "
 990                        "returned from key query\n");
 991                 rc = -EINVAL;
 992                 goto out;
 993         }
 994 out:
 995         return rc;
 996 }
 997
 998 /**
 999  * ecryptfs_find_auth_tok_for_sig
1000  * @auth_tok: Set to the matching auth_tok; NULL if not found
1001  * @crypt_stat: inode crypt_stat crypto context
1002  * @sig: Sig of auth_tok to find
1003  *
1004  * For now, this function simply looks at the registered auth_tok's
1005  * linked off the mount_crypt_stat, so all the auth_toks that can be
1006  * used must be registered at mount time. This function could
1007  * potentially try a lot harder to find auth_tok's (e.g., by calling
1008  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
1009  * that static registration of auth_tok's will no longer be necessary.
1010  *
1011  * Returns zero on no error; non-zero on error
1012  */
1013 static int
1014 ecryptfs_find_auth_tok_for_sig(
1015         struct ecryptfs_auth_tok **auth_tok,
1016         struct ecryptfs_crypt_stat *crypt_stat, char *sig)
1017 {
1018         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1019                 crypt_stat->mount_crypt_stat;
1020         struct ecryptfs_global_auth_tok *global_auth_tok;
1021         int rc = 0;
1022
1023         (*auth_tok) = NULL;
1024         if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
1025                                                   mount_crypt_stat, sig)) {
1026                 struct key *auth_tok_key;
1027
1028                 rc = ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key, auth_tok,
1029                                                        sig);
1030         } else
1031                 (*auth_tok) = global_auth_tok->global_auth_tok;
1032         return rc;
1033 }
1034
1035 /**
1036  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1037  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1038  * @crypt_stat: The cryptographic context
1039  *
1040  * Returns zero on success; non-zero error otherwise
1041  */
1042 static int
1043 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1044                                          struct ecryptfs_crypt_stat *crypt_stat)
1045 {
1046         struct scatterlist dst_sg[2];
1047         struct scatterlist src_sg[2];
1048         struct mutex *tfm_mutex;
1049         struct blkcipher_desc desc = {
1050                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1051         };
1052         int rc = 0;
1053
1054         if (unlikely(ecryptfs_verbosity > 0)) {
1055                 ecryptfs_printk(
1056                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1057                         auth_tok->token.password.session_key_encryption_key_bytes);
1058                 ecryptfs_dump_hex(
1059                         auth_tok->token.password.session_key_encryption_key,
1060                         auth_tok->token.password.session_key_encryption_key_bytes);
1061         }
1062         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1063                                                         crypt_stat->cipher);
1064         if (unlikely(rc)) {
1065                 printk(KERN_ERR "Internal error whilst attempting to get "
1066                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1067                        crypt_stat->cipher, rc);
1068                 goto out;
1069         }
1070         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1071                                  auth_tok->session_key.encrypted_key_size,
1072                                  src_sg, 2);
1073         if (rc < 1 || rc > 2) {
1074                 printk(KERN_ERR "Internal error whilst attempting to convert "
1075                         "auth_tok->session_key.encrypted_key to scatterlist; "
1076                         "expected rc = 1; got rc = [%d]. "
1077                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1078                         auth_tok->session_key.encrypted_key_size);
1079                 goto out;
1080         }
1081         auth_tok->session_key.decrypted_key_size =
1082                 auth_tok->session_key.encrypted_key_size;
1083         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1084                                  auth_tok->session_key.decrypted_key_size,
1085                                  dst_sg, 2);
1086         if (rc < 1 || rc > 2) {
1087                 printk(KERN_ERR "Internal error whilst attempting to convert "
1088                         "auth_tok->session_key.decrypted_key to scatterlist; "
1089                         "expected rc = 1; got rc = [%d]\n", rc);
1090                 goto out;
1091         }
1092         mutex_lock(tfm_mutex);
1093         rc = crypto_blkcipher_setkey(
1094                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1095                 crypt_stat->key_size);
1096         if (unlikely(rc < 0)) {
1097                 mutex_unlock(tfm_mutex);
1098                 printk(KERN_ERR "Error setting key for crypto context\n");
1099                 rc = -EINVAL;
1100                 goto out;
1101         }
1102         rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1103                                       auth_tok->session_key.encrypted_key_size);
1104         mutex_unlock(tfm_mutex);
1105         if (unlikely(rc)) {
1106                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1107                 goto out;
1108         }
1109         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1110         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1111                auth_tok->session_key.decrypted_key_size);
1112         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1113         if (unlikely(ecryptfs_verbosity > 0)) {
1114                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
1115                                 crypt_stat->key_size);
1116                 ecryptfs_dump_hex(crypt_stat->key,
1117                                   crypt_stat->key_size);
1118         }
1119 out:
1120         return rc;
1121 }
1122
1123 /**
1124  * ecryptfs_parse_packet_set
1125  * @crypt_stat: The cryptographic context
1126  * @src: Virtual address of region of memory containing the packets
1127  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1128  *
1129  * Get crypt_stat to have the file's session key if the requisite key
1130  * is available to decrypt the session key.
1131  *
1132  * Returns Zero if a valid authentication token was retrieved and
1133  * processed; negative value for file not encrypted or for error
1134  * conditions.
1135  */
1136 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1137                               unsigned char *src,
1138                               struct dentry *ecryptfs_dentry)
1139 {
1140         size_t i = 0;
1141         size_t found_auth_tok;
1142         size_t next_packet_is_auth_tok_packet;
1143         struct list_head auth_tok_list;
1144         struct ecryptfs_auth_tok *matching_auth_tok;
1145         struct ecryptfs_auth_tok *candidate_auth_tok;
1146         char *candidate_auth_tok_sig;
1147         size_t packet_size;
1148         struct ecryptfs_auth_tok *new_auth_tok;
1149         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1150         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1151         size_t tag_11_contents_size;
1152         size_t tag_11_packet_size;
1153         int rc = 0;
1154
1155         INIT_LIST_HEAD(&auth_tok_list);
1156         /* Parse the header to find as many packets as we can; these will be
1157          * added the our &auth_tok_list */
1158         next_packet_is_auth_tok_packet = 1;
1159         while (next_packet_is_auth_tok_packet) {
1160                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1161
1162                 switch (src[i]) {
1163                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1164                         rc = parse_tag_3_packet(crypt_stat,
1165                                                 (unsigned char *)&src[i],
1166                                                 &auth_tok_list, &new_auth_tok,
1167                                                 &packet_size, max_packet_size);
1168                         if (rc) {
1169                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1170                                                 "tag 3 packet\n");
1171                                 rc = -EIO;
1172                                 goto out_wipe_list;
1173                         }
1174                         i += packet_size;
1175                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1176                                                  sig_tmp_space,
1177                                                  ECRYPTFS_SIG_SIZE,
1178                                                  &tag_11_contents_size,
1179                                                  &tag_11_packet_size,
1180                                                  max_packet_size);
1181                         if (rc) {
1182                                 ecryptfs_printk(KERN_ERR, "No valid "
1183                                                 "(ecryptfs-specific) literal "
1184                                                 "packet containing "
1185                                                 "authentication token "
1186                                                 "signature found after "
1187                                                 "tag 3 packet\n");
1188                                 rc = -EIO;
1189                                 goto out_wipe_list;
1190                         }
1191                         i += tag_11_packet_size;
1192                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1193                                 ecryptfs_printk(KERN_ERR, "Expected "
1194                                                 "signature of size [%d]; "
1195                                                 "read size [%d]\n",
1196                                                 ECRYPTFS_SIG_SIZE,
1197                                                 tag_11_contents_size);
1198                                 rc = -EIO;
1199                                 goto out_wipe_list;
1200                         }
1201                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1202                                         sig_tmp_space, tag_11_contents_size);
1203                         new_auth_tok->token.password.signature[
1204                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1205                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1206                         break;
1207                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1208                         rc = parse_tag_1_packet(crypt_stat,
1209                                                 (unsigned char *)&src[i],
1210                                                 &auth_tok_list, &new_auth_tok,
1211                                                 &packet_size, max_packet_size);
1212                         if (rc) {
1213                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1214                                                 "tag 1 packet\n");
1215                                 rc = -EIO;
1216                                 goto out_wipe_list;
1217                         }
1218                         i += packet_size;
1219                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1220                         break;
1221                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1222                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1223                                         "(Tag 11 not allowed by itself)\n");
1224                         rc = -EIO;
1225                         goto out_wipe_list;
1226                         break;
1227                 default:
1228                         ecryptfs_printk(KERN_DEBUG, "No packet at offset "
1229                                         "[%d] of the file header; hex value of "
1230                                         "character is [0x%.2x]\n", i, src[i]);
1231                         next_packet_is_auth_tok_packet = 0;
1232                 }
1233         }
1234         if (list_empty(&auth_tok_list)) {
1235                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1236                        "eCryptfs file; this is not supported in this version "
1237                        "of the eCryptfs kernel module\n");
1238                 rc = -EINVAL;
1239                 goto out;
1240         }
1241         /* auth_tok_list contains the set of authentication tokens
1242          * parsed from the metadata. We need to find a matching
1243          * authentication token that has the secret component(s)
1244          * necessary to decrypt the EFEK in the auth_tok parsed from
1245          * the metadata. There may be several potential matches, but
1246          * just one will be sufficient to decrypt to get the FEK. */
1247 find_next_matching_auth_tok:
1248         found_auth_tok = 0;
1249         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1250                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1251                 if (unlikely(ecryptfs_verbosity > 0)) {
1252                         ecryptfs_printk(KERN_DEBUG,
1253                                         "Considering cadidate auth tok:\n");
1254                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1255                 }
1256                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1257                                                candidate_auth_tok);
1258                 if (rc) {
1259                         printk(KERN_ERR
1260                                "Unrecognized candidate auth tok type: [%d]\n",
1261                                candidate_auth_tok->token_type);
1262                         rc = -EINVAL;
1263                         goto out_wipe_list;
1264                 }
1265                 ecryptfs_find_auth_tok_for_sig(&matching_auth_tok, crypt_stat,
1266                                                candidate_auth_tok_sig);
1267                 if (matching_auth_tok) {
1268                         found_auth_tok = 1;
1269                         goto found_matching_auth_tok;
1270                 }
1271         }
1272         if (!found_auth_tok) {
1273                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1274                                 "authentication token\n");
1275                 rc = -EIO;
1276                 goto out_wipe_list;
1277         }
1278 found_matching_auth_tok:
1279         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1280                 memcpy(&(candidate_auth_tok->token.private_key),
1281                        &(matching_auth_tok->token.private_key),
1282                        sizeof(struct ecryptfs_private_key));
1283                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1284                                                        crypt_stat);
1285         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1286                 memcpy(&(candidate_auth_tok->token.password),
1287                        &(matching_auth_tok->token.password),
1288                        sizeof(struct ecryptfs_password));
1289                 rc = decrypt_passphrase_encrypted_session_key(
1290                         candidate_auth_tok, crypt_stat);
1291         }
1292         if (rc) {
1293                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1294
1295                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1296                                 "session key for authentication token with sig "
1297                                 "[%.*s]; rc = [%d]. Removing auth tok "
1298                                 "candidate from the list and searching for "
1299                                 "the next match.\n", candidate_auth_tok_sig,
1300                                 ECRYPTFS_SIG_SIZE_HEX, rc);
1301                 list_for_each_entry_safe(auth_tok_list_item,
1302                                          auth_tok_list_item_tmp,
1303                                          &auth_tok_list, list) {
1304                         if (candidate_auth_tok
1305                             == &auth_tok_list_item->auth_tok) {
1306                                 list_del(&auth_tok_list_item->list);
1307                                 kmem_cache_free(
1308                                         ecryptfs_auth_tok_list_item_cache,
1309                                         auth_tok_list_item);
1310                                 goto find_next_matching_auth_tok;
1311                         }
1312                 }
1313                 BUG();
1314         }
1315         rc = ecryptfs_compute_root_iv(crypt_stat);
1316         if (rc) {
1317                 ecryptfs_printk(KERN_ERR, "Error computing "
1318                                 "the root IV\n");
1319                 goto out_wipe_list;
1320         }
1321         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1322         if (rc) {
1323                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1324                                 "context for cipher [%s]; rc = [%d]\n",
1325                                 crypt_stat->cipher, rc);
1326         }
1327 out_wipe_list:
1328         wipe_auth_tok_list(&auth_tok_list);
1329 out:
1330         return rc;
1331 }
1332
1333 static int
1334 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1335                         struct ecryptfs_crypt_stat *crypt_stat,
1336                         struct ecryptfs_key_record *key_rec)
1337 {
1338         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1339         char *netlink_payload;
1340         size_t netlink_payload_length;
1341         struct ecryptfs_message *msg;
1342         int rc;
1343
1344         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1345                                  ecryptfs_code_for_cipher_string(crypt_stat),
1346                                  crypt_stat, &netlink_payload,
1347                                  &netlink_payload_length);
1348         if (rc) {
1349                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1350                 goto out;
1351         }
1352         rc = ecryptfs_send_message(ecryptfs_transport, netlink_payload,
1353                                    netlink_payload_length, &msg_ctx);
1354         if (rc) {
1355                 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
1356                 goto out;
1357         }
1358         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1359         if (rc) {
1360                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1361                                 "from the user space daemon\n");
1362                 rc = -EIO;
1363                 goto out;
1364         }
1365         rc = parse_tag_67_packet(key_rec, msg);
1366         if (rc)
1367                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1368         kfree(msg);
1369 out:
1370         if (netlink_payload)
1371                 kfree(netlink_payload);
1372         return rc;
1373 }
1374 /**
1375  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1376  * @dest: Buffer into which to write the packet
1377  * @remaining_bytes: Maximum number of bytes that can be writtn
1378  * @auth_tok: The authentication token used for generating the tag 1 packet
1379  * @crypt_stat: The cryptographic context
1380  * @key_rec: The key record struct for the tag 1 packet
1381  * @packet_size: This function will write the number of bytes that end
1382  *               up constituting the packet; set to zero on error
1383  *
1384  * Returns zero on success; non-zero on error.
1385  */
1386 static int
1387 write_tag_1_packet(char *dest, size_t *remaining_bytes,
1388                    struct ecryptfs_auth_tok *auth_tok,
1389                    struct ecryptfs_crypt_stat *crypt_stat,
1390                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1391 {
1392         size_t i;
1393         size_t encrypted_session_key_valid = 0;
1394         size_t packet_size_length;
1395         size_t max_packet_size;
1396         int rc = 0;
1397
1398         (*packet_size) = 0;
1399         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
1400                           ECRYPTFS_SIG_SIZE);
1401         encrypted_session_key_valid = 0;
1402         for (i = 0; i < crypt_stat->key_size; i++)
1403                 encrypted_session_key_valid |=
1404                         auth_tok->session_key.encrypted_key[i];
1405         if (encrypted_session_key_valid) {
1406                 memcpy(key_rec->enc_key,
1407                        auth_tok->session_key.encrypted_key,
1408                        auth_tok->session_key.encrypted_key_size);
1409                 goto encrypted_session_key_set;
1410         }
1411         if (auth_tok->session_key.encrypted_key_size == 0)
1412                 auth_tok->session_key.encrypted_key_size =
1413                         auth_tok->token.private_key.key_size;
1414         rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
1415         if (rc) {
1416                 printk(KERN_ERR "Failed to encrypt session key via a key "
1417                        "module; rc = [%d]\n", rc);
1418                 goto out;
1419         }
1420         if (ecryptfs_verbosity > 0) {
1421                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
1422                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
1423         }
1424 encrypted_session_key_set:
1425         /* This format is inspired by OpenPGP; see RFC 2440
1426          * packet tag 1 */
1427         max_packet_size = (1                         /* Tag 1 identifier */
1428                            + 3                       /* Max Tag 1 packet size */
1429                            + 1                       /* Version */
1430                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
1431                            + 1                       /* Cipher identifier */
1432                            + key_rec->enc_key_size); /* Encrypted key size */
1433         if (max_packet_size > (*remaining_bytes)) {
1434                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1435                        "need up to [%td] bytes, but there are only [%td] "
1436                        "available\n", max_packet_size, (*remaining_bytes));
1437                 rc = -EINVAL;
1438                 goto out;
1439         }
1440         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
1441         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
1442                                           (max_packet_size - 4),
1443                                           &packet_size_length);
1444         if (rc) {
1445                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
1446                                 "header; cannot generate packet length\n");
1447                 goto out;
1448         }
1449         (*packet_size) += packet_size_length;
1450         dest[(*packet_size)++] = 0x03; /* version 3 */
1451         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
1452         (*packet_size) += ECRYPTFS_SIG_SIZE;
1453         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
1454         memcpy(&dest[(*packet_size)], key_rec->enc_key,
1455                key_rec->enc_key_size);
1456         (*packet_size) += key_rec->enc_key_size;
1457 out:
1458         if (rc)
1459                 (*packet_size) = 0;
1460         else
1461                 (*remaining_bytes) -= (*packet_size);
1462         return rc;
1463 }
1464
1465 /**
1466  * write_tag_11_packet
1467  * @dest: Target into which Tag 11 packet is to be written
1468  * @remaining_bytes: Maximum packet length
1469  * @contents: Byte array of contents to copy in
1470  * @contents_length: Number of bytes in contents
1471  * @packet_length: Length of the Tag 11 packet written; zero on error
1472  *
1473  * Returns zero on success; non-zero on error.
1474  */
1475 static int
1476 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
1477                     size_t contents_length, size_t *packet_length)
1478 {
1479         size_t packet_size_length;
1480         size_t max_packet_size;
1481         int rc = 0;
1482
1483         (*packet_length) = 0;
1484         /* This format is inspired by OpenPGP; see RFC 2440
1485          * packet tag 11 */
1486         max_packet_size = (1                   /* Tag 11 identifier */
1487                            + 3                 /* Max Tag 11 packet size */
1488                            + 1                 /* Binary format specifier */
1489                            + 1                 /* Filename length */
1490                            + 8                 /* Filename ("_CONSOLE") */
1491                            + 4                 /* Modification date */
1492                            + contents_length); /* Literal data */
1493         if (max_packet_size > (*remaining_bytes)) {
1494                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1495                        "need up to [%td] bytes, but there are only [%td] "
1496                        "available\n", max_packet_size, (*remaining_bytes));
1497                 rc = -EINVAL;
1498                 goto out;
1499         }
1500         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
1501         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
1502                                           (max_packet_size - 4),
1503                                           &packet_size_length);
1504         if (rc) {
1505                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
1506                        "generate packet length. rc = [%d]\n", rc);
1507                 goto out;
1508         }
1509         (*packet_length) += packet_size_length;
1510         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
1511         dest[(*packet_length)++] = 8;
1512         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
1513         (*packet_length) += 8;
1514         memset(&dest[(*packet_length)], 0x00, 4);
1515         (*packet_length) += 4;
1516         memcpy(&dest[(*packet_length)], contents, contents_length);
1517         (*packet_length) += contents_length;
1518  out:
1519         if (rc)
1520                 (*packet_length) = 0;
1521         else
1522                 (*remaining_bytes) -= (*packet_length);
1523         return rc;
1524 }
1525
1526 /**
1527  * write_tag_3_packet
1528  * @dest: Buffer into which to write the packet
1529  * @remaining_bytes: Maximum number of bytes that can be written
1530  * @auth_tok: Authentication token
1531  * @crypt_stat: The cryptographic context
1532  * @key_rec: encrypted key
1533  * @packet_size: This function will write the number of bytes that end
1534  *               up constituting the packet; set to zero on error
1535  *
1536  * Returns zero on success; non-zero on error.
1537  */
1538 static int
1539 write_tag_3_packet(char *dest, size_t *remaining_bytes,
1540                    struct ecryptfs_auth_tok *auth_tok,
1541                    struct ecryptfs_crypt_stat *crypt_stat,
1542                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1543 {
1544         size_t i;
1545         size_t encrypted_session_key_valid = 0;
1546         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
1547         struct scatterlist dst_sg[2];
1548         struct scatterlist src_sg[2];
1549         struct mutex *tfm_mutex = NULL;
1550         u8 cipher_code;
1551         size_t packet_size_length;
1552         size_t max_packet_size;
1553         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1554                 crypt_stat->mount_crypt_stat;
1555         struct blkcipher_desc desc = {
1556                 .tfm = NULL,
1557                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1558         };
1559         int rc = 0;
1560
1561         (*packet_size) = 0;
1562         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
1563                           ECRYPTFS_SIG_SIZE);
1564         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1565                                                         crypt_stat->cipher);
1566         if (unlikely(rc)) {
1567                 printk(KERN_ERR "Internal error whilst attempting to get "
1568                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1569                        crypt_stat->cipher, rc);
1570                 goto out;
1571         }
1572         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
1573                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
1574
1575                 printk(KERN_WARNING "No key size specified at mount; "
1576                        "defaulting to [%d]\n", alg->max_keysize);
1577                 mount_crypt_stat->global_default_cipher_key_size =
1578                         alg->max_keysize;
1579         }
1580         if (crypt_stat->key_size == 0)
1581                 crypt_stat->key_size =
1582                         mount_crypt_stat->global_default_cipher_key_size;
1583         if (auth_tok->session_key.encrypted_key_size == 0)
1584                 auth_tok->session_key.encrypted_key_size =
1585                         crypt_stat->key_size;
1586         if (crypt_stat->key_size == 24
1587             && strcmp("aes", crypt_stat->cipher) == 0) {
1588                 memset((crypt_stat->key + 24), 0, 8);
1589                 auth_tok->session_key.encrypted_key_size = 32;
1590         } else
1591                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
1592         key_rec->enc_key_size =
1593                 auth_tok->session_key.encrypted_key_size;
1594         encrypted_session_key_valid = 0;
1595         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
1596                 encrypted_session_key_valid |=
1597                         auth_tok->session_key.encrypted_key[i];
1598         if (encrypted_session_key_valid) {
1599                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
1600                                 "using auth_tok->session_key.encrypted_key, "
1601                                 "where key_rec->enc_key_size = [%d]\n",
1602                                 key_rec->enc_key_size);
1603                 memcpy(key_rec->enc_key,
1604                        auth_tok->session_key.encrypted_key,
1605                        key_rec->enc_key_size);
1606                 goto encrypted_session_key_set;
1607         }
1608         if (auth_tok->token.password.flags &
1609             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
1610                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
1611                                 "session key encryption key of size [%d]\n",
1612                                 auth_tok->token.password.
1613                                 session_key_encryption_key_bytes);
1614                 memcpy(session_key_encryption_key,
1615                        auth_tok->token.password.session_key_encryption_key,
1616                        crypt_stat->key_size);
1617                 ecryptfs_printk(KERN_DEBUG,
1618                                 "Cached session key " "encryption key: \n");
1619                 if (ecryptfs_verbosity > 0)
1620                         ecryptfs_dump_hex(session_key_encryption_key, 16);
1621         }
1622         if (unlikely(ecryptfs_verbosity > 0)) {
1623                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
1624                 ecryptfs_dump_hex(session_key_encryption_key, 16);
1625         }
1626         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
1627                                  src_sg, 2);
1628         if (rc < 1 || rc > 2) {
1629                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1630                                 "for crypt_stat session key; expected rc = 1; "
1631                                 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1632                                 rc, key_rec->enc_key_size);
1633                 rc = -ENOMEM;
1634                 goto out;
1635         }
1636         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
1637                                  dst_sg, 2);
1638         if (rc < 1 || rc > 2) {
1639                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1640                                 "for crypt_stat encrypted session key; "
1641                                 "expected rc = 1; got rc = [%d]. "
1642                                 "key_rec->enc_key_size = [%d]\n", rc,
1643                                 key_rec->enc_key_size);
1644                 rc = -ENOMEM;
1645                 goto out;
1646         }
1647         mutex_lock(tfm_mutex);
1648         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
1649                                      crypt_stat->key_size);
1650         if (rc < 0) {
1651                 mutex_unlock(tfm_mutex);
1652                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
1653                                 "context; rc = [%d]\n", rc);
1654                 goto out;
1655         }
1656         rc = 0;
1657         ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
1658                         crypt_stat->key_size);
1659         rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
1660                                       (*key_rec).enc_key_size);
1661         mutex_unlock(tfm_mutex);
1662         if (rc) {
1663                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
1664                 goto out;
1665         }
1666         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
1667         if (ecryptfs_verbosity > 0) {
1668                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
1669                                 key_rec->enc_key_size);
1670                 ecryptfs_dump_hex(key_rec->enc_key,
1671                                   key_rec->enc_key_size);
1672         }
1673 encrypted_session_key_set:
1674         /* This format is inspired by OpenPGP; see RFC 2440
1675          * packet tag 3 */
1676         max_packet_size = (1                         /* Tag 3 identifier */
1677                            + 3                       /* Max Tag 3 packet size */
1678                            + 1                       /* Version */
1679                            + 1                       /* Cipher code */
1680                            + 1                       /* S2K specifier */
1681                            + 1                       /* Hash identifier */
1682                            + ECRYPTFS_SALT_SIZE      /* Salt */
1683                            + 1                       /* Hash iterations */
1684                            + key_rec->enc_key_size); /* Encrypted key size */
1685         if (max_packet_size > (*remaining_bytes)) {
1686                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
1687                        "there are only [%td] available\n", max_packet_size,
1688                        (*remaining_bytes));
1689                 rc = -EINVAL;
1690                 goto out;
1691         }
1692         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
1693         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1694          * to get the number of octets in the actual Tag 3 packet */
1695         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
1696                                           (max_packet_size - 4),
1697                                           &packet_size_length);
1698         if (rc) {
1699                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
1700                        "generate packet length. rc = [%d]\n", rc);
1701                 goto out;
1702         }
1703         (*packet_size) += packet_size_length;
1704         dest[(*packet_size)++] = 0x04; /* version 4 */
1705         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1706          * specified with strings */
1707         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat);
1708         if (cipher_code == 0) {
1709                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
1710                                 "cipher [%s]\n", crypt_stat->cipher);
1711                 rc = -EINVAL;
1712                 goto out;
1713         }
1714         dest[(*packet_size)++] = cipher_code;
1715         dest[(*packet_size)++] = 0x03;  /* S2K */
1716         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
1717         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
1718                ECRYPTFS_SALT_SIZE);
1719         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
1720         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
1721         memcpy(&dest[(*packet_size)], key_rec->enc_key,
1722                key_rec->enc_key_size);
1723         (*packet_size) += key_rec->enc_key_size;
1724 out:
1725         if (rc)
1726                 (*packet_size) = 0;
1727         else
1728                 (*remaining_bytes) -= (*packet_size);
1729         return rc;
1730 }
1731
1732 struct kmem_cache *ecryptfs_key_record_cache;
1733
1734 /**
1735  * ecryptfs_generate_key_packet_set
1736  * @dest_base: Virtual address from which to write the key record set
1737  * @crypt_stat: The cryptographic context from which the
1738  *              authentication tokens will be retrieved
1739  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1740  *                   for the global parameters
1741  * @len: The amount written
1742  * @max: The maximum amount of data allowed to be written
1743  *
1744  * Generates a key packet set and writes it to the virtual address
1745  * passed in.
1746  *
1747  * Returns zero on success; non-zero on error.
1748  */
1749 int
1750 ecryptfs_generate_key_packet_set(char *dest_base,
1751                                  struct ecryptfs_crypt_stat *crypt_stat,
1752                                  struct dentry *ecryptfs_dentry, size_t *len,
1753                                  size_t max)
1754 {
1755         struct ecryptfs_auth_tok *auth_tok;
1756         struct ecryptfs_global_auth_tok *global_auth_tok;
1757         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1758                 &ecryptfs_superblock_to_private(
1759                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
1760         size_t written;
1761         struct ecryptfs_key_record *key_rec;
1762         struct ecryptfs_key_sig *key_sig;
1763         int rc = 0;
1764
1765         (*len) = 0;
1766         mutex_lock(&crypt_stat->keysig_list_mutex);
1767         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
1768         if (!key_rec) {
1769                 rc = -ENOMEM;
1770                 goto out;
1771         }
1772         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
1773                             crypt_stat_list) {
1774                 memset(key_rec, 0, sizeof(*key_rec));
1775                 rc = ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
1776                                                            mount_crypt_stat,
1777                                                            key_sig->keysig);
1778                 if (rc) {
1779                         printk(KERN_ERR "Error attempting to get the global "
1780                                "auth_tok; rc = [%d]\n", rc);
1781                         goto out_free;
1782                 }
1783                 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
1784                         printk(KERN_WARNING
1785                                "Skipping invalid auth tok with sig = [%s]\n",
1786                                global_auth_tok->sig);
1787                         continue;
1788                 }
1789                 auth_tok = global_auth_tok->global_auth_tok;
1790                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
1791                         rc = write_tag_3_packet((dest_base + (*len)),
1792                                                 &max, auth_tok,
1793                                                 crypt_stat, key_rec,
1794                                                 &written);
1795                         if (rc) {
1796                                 ecryptfs_printk(KERN_WARNING, "Error "
1797                                                 "writing tag 3 packet\n");
1798                                 goto out_free;
1799                         }
1800                         (*len) += written;
1801                         /* Write auth tok signature packet */
1802                         rc = write_tag_11_packet((dest_base + (*len)), &max,
1803                                                  key_rec->sig,
1804                                                  ECRYPTFS_SIG_SIZE, &written);
1805                         if (rc) {
1806                                 ecryptfs_printk(KERN_ERR, "Error writing "
1807                                                 "auth tok signature packet\n");
1808                                 goto out_free;
1809                         }
1810                         (*len) += written;
1811                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1812                         rc = write_tag_1_packet(dest_base + (*len),
1813                                                 &max, auth_tok,
1814                                                 crypt_stat, key_rec, &written);
1815                         if (rc) {
1816                                 ecryptfs_printk(KERN_WARNING, "Error "
1817                                                 "writing tag 1 packet\n");
1818                                 goto out_free;
1819                         }
1820                         (*len) += written;
1821                 } else {
1822                         ecryptfs_printk(KERN_WARNING, "Unsupported "
1823                                         "authentication token type\n");
1824                         rc = -EINVAL;
1825                         goto out_free;
1826                 }
1827         }
1828         if (likely(max > 0)) {
1829                 dest_base[(*len)] = 0x00;
1830         } else {
1831                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
1832                 rc = -EIO;
1833         }
1834 out_free:
1835         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
1836 out:
1837         if (rc)
1838                 (*len) = 0;
1839         mutex_unlock(&crypt_stat->keysig_list_mutex);
1840         return rc;
1841 }
1842
1843 struct kmem_cache *ecryptfs_key_sig_cache;
1844
1845 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
1846 {
1847         struct ecryptfs_key_sig *new_key_sig;
1848         int rc = 0;
1849
1850         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
1851         if (!new_key_sig) {
1852                 rc = -ENOMEM;
1853                 printk(KERN_ERR
1854                        "Error allocating from ecryptfs_key_sig_cache\n");
1855                 goto out;
1856         }
1857         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
1858         mutex_lock(&crypt_stat->keysig_list_mutex);
1859         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
1860         mutex_unlock(&crypt_stat->keysig_list_mutex);
1861 out:
1862         return rc;
1863 }
1864
1865 struct kmem_cache *ecryptfs_global_auth_tok_cache;
1866
1867 int
1868 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1869                              char *sig)
1870 {
1871         struct ecryptfs_global_auth_tok *new_auth_tok;
1872         int rc = 0;
1873
1874         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
1875                                         GFP_KERNEL);
1876         if (!new_auth_tok) {
1877                 rc = -ENOMEM;
1878                 printk(KERN_ERR "Error allocating from "
1879                        "ecryptfs_global_auth_tok_cache\n");
1880                 goto out;
1881         }
1882         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
1883         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
1884         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
1885         list_add(&new_auth_tok->mount_crypt_stat_list,
1886                  &mount_crypt_stat->global_auth_tok_list);
1887         mount_crypt_stat->num_global_auth_toks++;
1888         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
1889 out:
1890         return rc;
1891 }
1892